2005-04-16 22:20:36 +00:00
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/*
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* NSA Security-Enhanced Linux (SELinux) security module
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*
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* This file contains the SELinux hook function implementations.
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*
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* Authors: Stephen Smalley, <sds@epoch.ncsc.mil>
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2008-04-17 17:17:49 +00:00
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* Chris Vance, <cvance@nai.com>
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* Wayne Salamon, <wsalamon@nai.com>
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* James Morris <jmorris@redhat.com>
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2005-04-16 22:20:36 +00:00
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*
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* Copyright (C) 2001,2002 Networks Associates Technology, Inc.
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2008-07-03 23:47:13 +00:00
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* Copyright (C) 2003-2008 Red Hat, Inc., James Morris <jmorris@redhat.com>
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* Eric Paris <eparis@redhat.com>
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2005-04-16 22:20:36 +00:00
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* Copyright (C) 2004-2005 Trusted Computer Solutions, Inc.
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2008-04-17 17:17:49 +00:00
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* <dgoeddel@trustedcs.com>
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2009-08-28 22:12:49 +00:00
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* Copyright (C) 2006, 2007, 2009 Hewlett-Packard Development Company, L.P.
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2011-08-01 11:10:33 +00:00
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* Paul Moore <paul@paul-moore.com>
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2007-09-14 00:27:07 +00:00
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* Copyright (C) 2007 Hitachi Software Engineering Co., Ltd.
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2008-04-17 17:17:49 +00:00
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* Yuichi Nakamura <ynakam@hitachisoft.jp>
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2005-04-16 22:20:36 +00:00
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2,
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2008-04-17 17:17:49 +00:00
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* as published by the Free Software Foundation.
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2005-04-16 22:20:36 +00:00
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*/
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#include <linux/init.h>
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2011-02-25 20:39:20 +00:00
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#include <linux/kd.h>
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2005-04-16 22:20:36 +00:00
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#include <linux/kernel.h>
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2008-07-26 02:45:49 +00:00
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#include <linux/tracehook.h>
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2005-04-16 22:20:36 +00:00
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#include <linux/errno.h>
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#include <linux/sched.h>
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#include <linux/security.h>
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#include <linux/xattr.h>
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#include <linux/capability.h>
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#include <linux/unistd.h>
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#include <linux/mm.h>
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#include <linux/mman.h>
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#include <linux/slab.h>
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#include <linux/pagemap.h>
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2011-02-25 20:39:20 +00:00
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#include <linux/proc_fs.h>
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2005-04-16 22:20:36 +00:00
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#include <linux/swap.h>
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#include <linux/spinlock.h>
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#include <linux/syscalls.h>
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2011-02-01 16:05:39 +00:00
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#include <linux/dcache.h>
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2005-04-16 22:20:36 +00:00
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#include <linux/file.h>
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2008-04-24 11:44:08 +00:00
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#include <linux/fdtable.h>
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2005-04-16 22:20:36 +00:00
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#include <linux/namei.h>
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#include <linux/mount.h>
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#include <linux/netfilter_ipv4.h>
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#include <linux/netfilter_ipv6.h>
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#include <linux/tty.h>
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#include <net/icmp.h>
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2007-10-11 00:30:46 +00:00
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#include <net/ip.h> /* for local_port_range[] */
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2013-04-08 17:58:11 +00:00
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#include <net/sock.h>
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2005-04-16 22:20:36 +00:00
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#include <net/tcp.h> /* struct or_callable used in sock_rcv_skb */
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2013-12-04 21:10:45 +00:00
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#include <net/inet_connection_sock.h>
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2008-01-29 13:38:23 +00:00
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#include <net/net_namespace.h>
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2008-01-29 13:43:36 +00:00
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#include <net/netlabel.h>
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2008-05-14 15:27:45 +00:00
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#include <linux/uaccess.h>
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2005-04-16 22:20:36 +00:00
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#include <asm/ioctls.h>
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2011-07-26 23:09:06 +00:00
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#include <linux/atomic.h>
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2005-04-16 22:20:36 +00:00
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#include <linux/bitops.h>
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#include <linux/interrupt.h>
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#include <linux/netdevice.h> /* for network interface checks */
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2013-03-27 06:49:35 +00:00
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#include <net/netlink.h>
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2005-04-16 22:20:36 +00:00
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#include <linux/tcp.h>
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#include <linux/udp.h>
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2006-11-14 00:09:01 +00:00
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#include <linux/dccp.h>
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2005-04-16 22:20:36 +00:00
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#include <linux/quota.h>
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#include <linux/un.h> /* for Unix socket types */
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#include <net/af_unix.h> /* for Unix socket types */
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#include <linux/parser.h>
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#include <linux/nfs_mount.h>
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#include <net/ipv6.h>
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#include <linux/hugetlb.h>
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#include <linux/personality.h>
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#include <linux/audit.h>
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2005-06-30 09:58:51 +00:00
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#include <linux/string.h>
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[AF_UNIX]: Datagram getpeersec
This patch implements an API whereby an application can determine the
label of its peer's Unix datagram sockets via the auxiliary data mechanism of
recvmsg.
Patch purpose:
This patch enables a security-aware application to retrieve the
security context of the peer of a Unix datagram socket. The application
can then use this security context to determine the security context for
processing on behalf of the peer who sent the packet.
Patch design and implementation:
The design and implementation is very similar to the UDP case for INET
sockets. Basically we build upon the existing Unix domain socket API for
retrieving user credentials. Linux offers the API for obtaining user
credentials via ancillary messages (i.e., out of band/control messages
that are bundled together with a normal message). To retrieve the security
context, the application first indicates to the kernel such desire by
setting the SO_PASSSEC option via getsockopt. Then the application
retrieves the security context using the auxiliary data mechanism.
An example server application for Unix datagram socket should look like this:
toggle = 1;
toggle_len = sizeof(toggle);
setsockopt(sockfd, SOL_SOCKET, SO_PASSSEC, &toggle, &toggle_len);
recvmsg(sockfd, &msg_hdr, 0);
if (msg_hdr.msg_controllen > sizeof(struct cmsghdr)) {
cmsg_hdr = CMSG_FIRSTHDR(&msg_hdr);
if (cmsg_hdr->cmsg_len <= CMSG_LEN(sizeof(scontext)) &&
cmsg_hdr->cmsg_level == SOL_SOCKET &&
cmsg_hdr->cmsg_type == SCM_SECURITY) {
memcpy(&scontext, CMSG_DATA(cmsg_hdr), sizeof(scontext));
}
}
sock_setsockopt is enhanced with a new socket option SOCK_PASSSEC to allow
a server socket to receive security context of the peer.
Testing:
We have tested the patch by setting up Unix datagram client and server
applications. We verified that the server can retrieve the security context
using the auxiliary data mechanism of recvmsg.
Signed-off-by: Catherine Zhang <cxzhang@watson.ibm.com>
Acked-by: Acked-by: James Morris <jmorris@namei.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-06-29 19:27:47 +00:00
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#include <linux/selinux.h>
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2006-09-26 06:32:01 +00:00
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#include <linux/mutex.h>
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timers: fix itimer/many thread hang
Overview
This patch reworks the handling of POSIX CPU timers, including the
ITIMER_PROF, ITIMER_VIRT timers and rlimit handling. It was put together
with the help of Roland McGrath, the owner and original writer of this code.
The problem we ran into, and the reason for this rework, has to do with using
a profiling timer in a process with a large number of threads. It appears
that the performance of the old implementation of run_posix_cpu_timers() was
at least O(n*3) (where "n" is the number of threads in a process) or worse.
Everything is fine with an increasing number of threads until the time taken
for that routine to run becomes the same as or greater than the tick time, at
which point things degrade rather quickly.
This patch fixes bug 9906, "Weird hang with NPTL and SIGPROF."
Code Changes
This rework corrects the implementation of run_posix_cpu_timers() to make it
run in constant time for a particular machine. (Performance may vary between
one machine and another depending upon whether the kernel is built as single-
or multiprocessor and, in the latter case, depending upon the number of
running processors.) To do this, at each tick we now update fields in
signal_struct as well as task_struct. The run_posix_cpu_timers() function
uses those fields to make its decisions.
We define a new structure, "task_cputime," to contain user, system and
scheduler times and use these in appropriate places:
struct task_cputime {
cputime_t utime;
cputime_t stime;
unsigned long long sum_exec_runtime;
};
This is included in the structure "thread_group_cputime," which is a new
substructure of signal_struct and which varies for uniprocessor versus
multiprocessor kernels. For uniprocessor kernels, it uses "task_cputime" as
a simple substructure, while for multiprocessor kernels it is a pointer:
struct thread_group_cputime {
struct task_cputime totals;
};
struct thread_group_cputime {
struct task_cputime *totals;
};
We also add a new task_cputime substructure directly to signal_struct, to
cache the earliest expiration of process-wide timers, and task_cputime also
replaces the it_*_expires fields of task_struct (used for earliest expiration
of thread timers). The "thread_group_cputime" structure contains process-wide
timers that are updated via account_user_time() and friends. In the non-SMP
case the structure is a simple aggregator; unfortunately in the SMP case that
simplicity was not achievable due to cache-line contention between CPUs (in
one measured case performance was actually _worse_ on a 16-cpu system than
the same test on a 4-cpu system, due to this contention). For SMP, the
thread_group_cputime counters are maintained as a per-cpu structure allocated
using alloc_percpu(). The timer functions update only the timer field in
the structure corresponding to the running CPU, obtained using per_cpu_ptr().
We define a set of inline functions in sched.h that we use to maintain the
thread_group_cputime structure and hide the differences between UP and SMP
implementations from the rest of the kernel. The thread_group_cputime_init()
function initializes the thread_group_cputime structure for the given task.
The thread_group_cputime_alloc() is a no-op for UP; for SMP it calls the
out-of-line function thread_group_cputime_alloc_smp() to allocate and fill
in the per-cpu structures and fields. The thread_group_cputime_free()
function, also a no-op for UP, in SMP frees the per-cpu structures. The
thread_group_cputime_clone_thread() function (also a UP no-op) for SMP calls
thread_group_cputime_alloc() if the per-cpu structures haven't yet been
allocated. The thread_group_cputime() function fills the task_cputime
structure it is passed with the contents of the thread_group_cputime fields;
in UP it's that simple but in SMP it must also safely check that tsk->signal
is non-NULL (if it is it just uses the appropriate fields of task_struct) and,
if so, sums the per-cpu values for each online CPU. Finally, the three
functions account_group_user_time(), account_group_system_time() and
account_group_exec_runtime() are used by timer functions to update the
respective fields of the thread_group_cputime structure.
Non-SMP operation is trivial and will not be mentioned further.
The per-cpu structure is always allocated when a task creates its first new
thread, via a call to thread_group_cputime_clone_thread() from copy_signal().
It is freed at process exit via a call to thread_group_cputime_free() from
cleanup_signal().
All functions that formerly summed utime/stime/sum_sched_runtime values from
from all threads in the thread group now use thread_group_cputime() to
snapshot the values in the thread_group_cputime structure or the values in
the task structure itself if the per-cpu structure hasn't been allocated.
Finally, the code in kernel/posix-cpu-timers.c has changed quite a bit.
The run_posix_cpu_timers() function has been split into a fast path and a
slow path; the former safely checks whether there are any expired thread
timers and, if not, just returns, while the slow path does the heavy lifting.
With the dedicated thread group fields, timers are no longer "rebalanced" and
the process_timer_rebalance() function and related code has gone away. All
summing loops are gone and all code that used them now uses the
thread_group_cputime() inline. When process-wide timers are set, the new
task_cputime structure in signal_struct is used to cache the earliest
expiration; this is checked in the fast path.
Performance
The fix appears not to add significant overhead to existing operations. It
generally performs the same as the current code except in two cases, one in
which it performs slightly worse (Case 5 below) and one in which it performs
very significantly better (Case 2 below). Overall it's a wash except in those
two cases.
I've since done somewhat more involved testing on a dual-core Opteron system.
Case 1: With no itimer running, for a test with 100,000 threads, the fixed
kernel took 1428.5 seconds, 513 seconds more than the unfixed system,
all of which was spent in the system. There were twice as many
voluntary context switches with the fix as without it.
Case 2: With an itimer running at .01 second ticks and 4000 threads (the most
an unmodified kernel can handle), the fixed kernel ran the test in
eight percent of the time (5.8 seconds as opposed to 70 seconds) and
had better tick accuracy (.012 seconds per tick as opposed to .023
seconds per tick).
Case 3: A 4000-thread test with an initial timer tick of .01 second and an
interval of 10,000 seconds (i.e. a timer that ticks only once) had
very nearly the same performance in both cases: 6.3 seconds elapsed
for the fixed kernel versus 5.5 seconds for the unfixed kernel.
With fewer threads (eight in these tests), the Case 1 test ran in essentially
the same time on both the modified and unmodified kernels (5.2 seconds versus
5.8 seconds). The Case 2 test ran in about the same time as well, 5.9 seconds
versus 5.4 seconds but again with much better tick accuracy, .013 seconds per
tick versus .025 seconds per tick for the unmodified kernel.
Since the fix affected the rlimit code, I also tested soft and hard CPU limits.
Case 4: With a hard CPU limit of 20 seconds and eight threads (and an itimer
running), the modified kernel was very slightly favored in that while
it killed the process in 19.997 seconds of CPU time (5.002 seconds of
wall time), only .003 seconds of that was system time, the rest was
user time. The unmodified kernel killed the process in 20.001 seconds
of CPU (5.014 seconds of wall time) of which .016 seconds was system
time. Really, though, the results were too close to call. The results
were essentially the same with no itimer running.
Case 5: With a soft limit of 20 seconds and a hard limit of 2000 seconds
(where the hard limit would never be reached) and an itimer running,
the modified kernel exhibited worse tick accuracy than the unmodified
kernel: .050 seconds/tick versus .028 seconds/tick. Otherwise,
performance was almost indistinguishable. With no itimer running this
test exhibited virtually identical behavior and times in both cases.
In times past I did some limited performance testing. those results are below.
On a four-cpu Opteron system without this fix, a sixteen-thread test executed
in 3569.991 seconds, of which user was 3568.435s and system was 1.556s. On
the same system with the fix, user and elapsed time were about the same, but
system time dropped to 0.007 seconds. Performance with eight, four and one
thread were comparable. Interestingly, the timer ticks with the fix seemed
more accurate: The sixteen-thread test with the fix received 149543 ticks
for 0.024 seconds per tick, while the same test without the fix received 58720
for 0.061 seconds per tick. Both cases were configured for an interval of
0.01 seconds. Again, the other tests were comparable. Each thread in this
test computed the primes up to 25,000,000.
I also did a test with a large number of threads, 100,000 threads, which is
impossible without the fix. In this case each thread computed the primes only
up to 10,000 (to make the runtime manageable). System time dominated, at
1546.968 seconds out of a total 2176.906 seconds (giving a user time of
629.938s). It received 147651 ticks for 0.015 seconds per tick, still quite
accurate. There is obviously no comparable test without the fix.
Signed-off-by: Frank Mayhar <fmayhar@google.com>
Cc: Roland McGrath <roland@redhat.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-09-12 16:54:39 +00:00
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#include <linux/posix-timers.h>
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2010-02-03 23:36:43 +00:00
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#include <linux/syslog.h>
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userns: security: make capabilities relative to the user namespace
- Introduce ns_capable to test for a capability in a non-default
user namespace.
- Teach cap_capable to handle capabilities in a non-default
user namespace.
The motivation is to get to the unprivileged creation of new
namespaces. It looks like this gets us 90% of the way there, with
only potential uid confusion issues left.
I still need to handle getting all caps after creation but otherwise I
think I have a good starter patch that achieves all of your goals.
Changelog:
11/05/2010: [serge] add apparmor
12/14/2010: [serge] fix capabilities to created user namespaces
Without this, if user serge creates a user_ns, he won't have
capabilities to the user_ns he created. THis is because we
were first checking whether his effective caps had the caps
he needed and returning -EPERM if not, and THEN checking whether
he was the creator. Reverse those checks.
12/16/2010: [serge] security_real_capable needs ns argument in !security case
01/11/2011: [serge] add task_ns_capable helper
01/11/2011: [serge] add nsown_capable() helper per Bastian Blank suggestion
02/16/2011: [serge] fix a logic bug: the root user is always creator of
init_user_ns, but should not always have capabilities to
it! Fix the check in cap_capable().
02/21/2011: Add the required user_ns parameter to security_capable,
fixing a compile failure.
02/23/2011: Convert some macros to functions as per akpm comments. Some
couldn't be converted because we can't easily forward-declare
them (they are inline if !SECURITY, extern if SECURITY). Add
a current_user_ns function so we can use it in capability.h
without #including cred.h. Move all forward declarations
together to the top of the #ifdef __KERNEL__ section, and use
kernel-doc format.
02/23/2011: Per dhowells, clean up comment in cap_capable().
02/23/2011: Per akpm, remove unreachable 'return -EPERM' in cap_capable.
(Original written and signed off by Eric; latest, modified version
acked by him)
[akpm@linux-foundation.org: fix build]
[akpm@linux-foundation.org: export current_user_ns() for ecryptfs]
[serge.hallyn@canonical.com: remove unneeded extra argument in selinux's task_has_capability]
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Serge E. Hallyn <serge.hallyn@canonical.com>
Acked-by: "Eric W. Biederman" <ebiederm@xmission.com>
Acked-by: Daniel Lezcano <daniel.lezcano@free.fr>
Acked-by: David Howells <dhowells@redhat.com>
Cc: James Morris <jmorris@namei.org>
Signed-off-by: Serge E. Hallyn <serge.hallyn@canonical.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-03-23 23:43:17 +00:00
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#include <linux/user_namespace.h>
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2011-05-27 00:52:10 +00:00
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#include <linux/export.h>
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2012-02-13 03:58:52 +00:00
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#include <linux/msg.h>
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#include <linux/shm.h>
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2005-04-16 22:20:36 +00:00
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#include "avc.h"
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#include "objsec.h"
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#include "netif.h"
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2008-01-29 13:38:13 +00:00
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#include "netnode.h"
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2008-04-10 14:48:14 +00:00
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#include "netport.h"
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[LSM-IPSec]: Per-packet access control.
This patch series implements per packet access control via the
extension of the Linux Security Modules (LSM) interface by hooks in
the XFRM and pfkey subsystems that leverage IPSec security
associations to label packets. Extensions to the SELinux LSM are
included that leverage the patch for this purpose.
This patch implements the changes necessary to the SELinux LSM to
create, deallocate, and use security contexts for policies
(xfrm_policy) and security associations (xfrm_state) that enable
control of a socket's ability to send and receive packets.
Patch purpose:
The patch is designed to enable the SELinux LSM to implement access
control on individual packets based on the strongly authenticated
IPSec security association. Such access controls augment the existing
ones in SELinux based on network interface and IP address. The former
are very coarse-grained, and the latter can be spoofed. By using
IPSec, the SELinux can control access to remote hosts based on
cryptographic keys generated using the IPSec mechanism. This enables
access control on a per-machine basis or per-application if the remote
machine is running the same mechanism and trusted to enforce the
access control policy.
Patch design approach:
The patch's main function is to authorize a socket's access to a IPSec
policy based on their security contexts. Since the communication is
implemented by a security association, the patch ensures that the
security association's negotiated and used have the same security
context. The patch enables allocation and deallocation of such
security contexts for policies and security associations. It also
enables copying of the security context when policies are cloned.
Lastly, the patch ensures that packets that are sent without using a
IPSec security assocation with a security context are allowed to be
sent in that manner.
A presentation available at
www.selinux-symposium.org/2005/presentations/session2/2-3-jaeger.pdf
from the SELinux symposium describes the overall approach.
Patch implementation details:
The function which authorizes a socket to perform a requested
operation (send/receive) on a IPSec policy (xfrm_policy) is
selinux_xfrm_policy_lookup. The Netfilter and rcv_skb hooks ensure
that if a IPSec SA with a securit y association has not been used,
then the socket is allowed to send or receive the packet,
respectively.
The patch implements SELinux function for allocating security contexts
when policies (xfrm_policy) are created via the pfkey or xfrm_user
interfaces via selinux_xfrm_policy_alloc. When a security association
is built, SELinux allocates the security context designated by the
XFRM subsystem which is based on that of the authorized policy via
selinux_xfrm_state_alloc.
When a xfrm_policy is cloned, the security context of that policy, if
any, is copied to the clone via selinux_xfrm_policy_clone.
When a xfrm_policy or xfrm_state is freed, its security context, if
any is also freed at selinux_xfrm_policy_free or
selinux_xfrm_state_free.
Testing:
The SELinux authorization function is tested using ipsec-tools. We
created policies and security associations with particular security
contexts and added SELinux access control policy entries to verify the
authorization decision. We also made sure that packets for which no
security context was supplied (which either did or did not use
security associations) were authorized using an unlabelled context.
Signed-off-by: Trent Jaeger <tjaeger@cse.psu.edu>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
2005-12-14 07:12:40 +00:00
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#include "xfrm.h"
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2007-02-28 20:14:23 +00:00
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#include "netlabel.h"
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2008-03-01 20:03:14 +00:00
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#include "audit.h"
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2011-08-30 02:52:32 +00:00
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#include "avc_ss.h"
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2005-04-16 22:20:36 +00:00
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2007-10-17 06:31:32 +00:00
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extern struct security_operations *security_ops;
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2005-04-16 22:20:36 +00:00
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2008-01-29 13:43:36 +00:00
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/* SECMARK reference count */
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2011-08-17 01:08:43 +00:00
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static atomic_t selinux_secmark_refcount = ATOMIC_INIT(0);
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2008-01-29 13:43:36 +00:00
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2005-04-16 22:20:36 +00:00
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#ifdef CONFIG_SECURITY_SELINUX_DEVELOP
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2008-04-17 17:17:49 +00:00
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int selinux_enforcing;
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2005-04-16 22:20:36 +00:00
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static int __init enforcing_setup(char *str)
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{
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2008-05-14 15:27:45 +00:00
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unsigned long enforcing;
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2014-02-05 06:13:14 +00:00
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if (!kstrtoul(str, 0, &enforcing))
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2008-05-14 15:27:45 +00:00
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selinux_enforcing = enforcing ? 1 : 0;
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2005-04-16 22:20:36 +00:00
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return 1;
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}
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__setup("enforcing=", enforcing_setup);
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#endif
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#ifdef CONFIG_SECURITY_SELINUX_BOOTPARAM
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int selinux_enabled = CONFIG_SECURITY_SELINUX_BOOTPARAM_VALUE;
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static int __init selinux_enabled_setup(char *str)
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{
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2008-05-14 15:27:45 +00:00
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unsigned long enabled;
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2014-02-05 06:13:14 +00:00
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if (!kstrtoul(str, 0, &enabled))
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2008-05-14 15:27:45 +00:00
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selinux_enabled = enabled ? 1 : 0;
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2005-04-16 22:20:36 +00:00
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return 1;
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}
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__setup("selinux=", selinux_enabled_setup);
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2006-05-03 14:52:36 +00:00
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#else
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int selinux_enabled = 1;
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2005-04-16 22:20:36 +00:00
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#endif
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2006-12-07 04:33:20 +00:00
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static struct kmem_cache *sel_inode_cache;
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2006-03-22 08:09:22 +00:00
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2008-01-29 13:43:36 +00:00
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/**
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* selinux_secmark_enabled - Check to see if SECMARK is currently enabled
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*
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* Description:
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* This function checks the SECMARK reference counter to see if any SECMARK
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* targets are currently configured, if the reference counter is greater than
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* zero SECMARK is considered to be enabled. Returns true (1) if SECMARK is
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2013-05-03 13:05:39 +00:00
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* enabled, false (0) if SECMARK is disabled. If the always_check_network
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* policy capability is enabled, SECMARK is always considered enabled.
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2008-01-29 13:43:36 +00:00
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*
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*/
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static int selinux_secmark_enabled(void)
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{
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2013-05-03 13:05:39 +00:00
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return (selinux_policycap_alwaysnetwork || atomic_read(&selinux_secmark_refcount));
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}
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/**
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* selinux_peerlbl_enabled - Check to see if peer labeling is currently enabled
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*
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* Description:
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* This function checks if NetLabel or labeled IPSEC is enabled. Returns true
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* (1) if any are enabled or false (0) if neither are enabled. If the
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* always_check_network policy capability is enabled, peer labeling
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* is always considered enabled.
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*
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*/
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static int selinux_peerlbl_enabled(void)
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{
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return (selinux_policycap_alwaysnetwork || netlbl_enabled() || selinux_xfrm_enabled());
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2008-01-29 13:43:36 +00:00
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}
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CRED: Inaugurate COW credentials
Inaugurate copy-on-write credentials management. This uses RCU to manage the
credentials pointer in the task_struct with respect to accesses by other tasks.
A process may only modify its own credentials, and so does not need locking to
access or modify its own credentials.
A mutex (cred_replace_mutex) is added to the task_struct to control the effect
of PTRACE_ATTACHED on credential calculations, particularly with respect to
execve().
With this patch, the contents of an active credentials struct may not be
changed directly; rather a new set of credentials must be prepared, modified
and committed using something like the following sequence of events:
struct cred *new = prepare_creds();
int ret = blah(new);
if (ret < 0) {
abort_creds(new);
return ret;
}
return commit_creds(new);
There are some exceptions to this rule: the keyrings pointed to by the active
credentials may be instantiated - keyrings violate the COW rule as managing
COW keyrings is tricky, given that it is possible for a task to directly alter
the keys in a keyring in use by another task.
To help enforce this, various pointers to sets of credentials, such as those in
the task_struct, are declared const. The purpose of this is compile-time
discouragement of altering credentials through those pointers. Once a set of
credentials has been made public through one of these pointers, it may not be
modified, except under special circumstances:
(1) Its reference count may incremented and decremented.
(2) The keyrings to which it points may be modified, but not replaced.
The only safe way to modify anything else is to create a replacement and commit
using the functions described in Documentation/credentials.txt (which will be
added by a later patch).
This patch and the preceding patches have been tested with the LTP SELinux
testsuite.
This patch makes several logical sets of alteration:
(1) execve().
This now prepares and commits credentials in various places in the
security code rather than altering the current creds directly.
(2) Temporary credential overrides.
do_coredump() and sys_faccessat() now prepare their own credentials and
temporarily override the ones currently on the acting thread, whilst
preventing interference from other threads by holding cred_replace_mutex
on the thread being dumped.
This will be replaced in a future patch by something that hands down the
credentials directly to the functions being called, rather than altering
the task's objective credentials.
(3) LSM interface.
A number of functions have been changed, added or removed:
(*) security_capset_check(), ->capset_check()
(*) security_capset_set(), ->capset_set()
Removed in favour of security_capset().
(*) security_capset(), ->capset()
New. This is passed a pointer to the new creds, a pointer to the old
creds and the proposed capability sets. It should fill in the new
creds or return an error. All pointers, barring the pointer to the
new creds, are now const.
(*) security_bprm_apply_creds(), ->bprm_apply_creds()
Changed; now returns a value, which will cause the process to be
killed if it's an error.
(*) security_task_alloc(), ->task_alloc_security()
Removed in favour of security_prepare_creds().
(*) security_cred_free(), ->cred_free()
New. Free security data attached to cred->security.
(*) security_prepare_creds(), ->cred_prepare()
New. Duplicate any security data attached to cred->security.
(*) security_commit_creds(), ->cred_commit()
New. Apply any security effects for the upcoming installation of new
security by commit_creds().
(*) security_task_post_setuid(), ->task_post_setuid()
Removed in favour of security_task_fix_setuid().
(*) security_task_fix_setuid(), ->task_fix_setuid()
Fix up the proposed new credentials for setuid(). This is used by
cap_set_fix_setuid() to implicitly adjust capabilities in line with
setuid() changes. Changes are made to the new credentials, rather
than the task itself as in security_task_post_setuid().
(*) security_task_reparent_to_init(), ->task_reparent_to_init()
Removed. Instead the task being reparented to init is referred
directly to init's credentials.
NOTE! This results in the loss of some state: SELinux's osid no
longer records the sid of the thread that forked it.
(*) security_key_alloc(), ->key_alloc()
(*) security_key_permission(), ->key_permission()
Changed. These now take cred pointers rather than task pointers to
refer to the security context.
(4) sys_capset().
This has been simplified and uses less locking. The LSM functions it
calls have been merged.
(5) reparent_to_kthreadd().
This gives the current thread the same credentials as init by simply using
commit_thread() to point that way.
(6) __sigqueue_alloc() and switch_uid()
__sigqueue_alloc() can't stop the target task from changing its creds
beneath it, so this function gets a reference to the currently applicable
user_struct which it then passes into the sigqueue struct it returns if
successful.
switch_uid() is now called from commit_creds(), and possibly should be
folded into that. commit_creds() should take care of protecting
__sigqueue_alloc().
(7) [sg]et[ug]id() and co and [sg]et_current_groups.
The set functions now all use prepare_creds(), commit_creds() and
abort_creds() to build and check a new set of credentials before applying
it.
security_task_set[ug]id() is called inside the prepared section. This
guarantees that nothing else will affect the creds until we've finished.
The calling of set_dumpable() has been moved into commit_creds().
Much of the functionality of set_user() has been moved into
commit_creds().
The get functions all simply access the data directly.
(8) security_task_prctl() and cap_task_prctl().
security_task_prctl() has been modified to return -ENOSYS if it doesn't
want to handle a function, or otherwise return the return value directly
rather than through an argument.
Additionally, cap_task_prctl() now prepares a new set of credentials, even
if it doesn't end up using it.
(9) Keyrings.
A number of changes have been made to the keyrings code:
(a) switch_uid_keyring(), copy_keys(), exit_keys() and suid_keys() have
all been dropped and built in to the credentials functions directly.
They may want separating out again later.
(b) key_alloc() and search_process_keyrings() now take a cred pointer
rather than a task pointer to specify the security context.
(c) copy_creds() gives a new thread within the same thread group a new
thread keyring if its parent had one, otherwise it discards the thread
keyring.
(d) The authorisation key now points directly to the credentials to extend
the search into rather pointing to the task that carries them.
(e) Installing thread, process or session keyrings causes a new set of
credentials to be created, even though it's not strictly necessary for
process or session keyrings (they're shared).
(10) Usermode helper.
The usermode helper code now carries a cred struct pointer in its
subprocess_info struct instead of a new session keyring pointer. This set
of credentials is derived from init_cred and installed on the new process
after it has been cloned.
call_usermodehelper_setup() allocates the new credentials and
call_usermodehelper_freeinfo() discards them if they haven't been used. A
special cred function (prepare_usermodeinfo_creds()) is provided
specifically for call_usermodehelper_setup() to call.
call_usermodehelper_setkeys() adjusts the credentials to sport the
supplied keyring as the new session keyring.
(11) SELinux.
SELinux has a number of changes, in addition to those to support the LSM
interface changes mentioned above:
(a) selinux_setprocattr() no longer does its check for whether the
current ptracer can access processes with the new SID inside the lock
that covers getting the ptracer's SID. Whilst this lock ensures that
the check is done with the ptracer pinned, the result is only valid
until the lock is released, so there's no point doing it inside the
lock.
(12) is_single_threaded().
This function has been extracted from selinux_setprocattr() and put into
a file of its own in the lib/ directory as join_session_keyring() now
wants to use it too.
The code in SELinux just checked to see whether a task shared mm_structs
with other tasks (CLONE_VM), but that isn't good enough. We really want
to know if they're part of the same thread group (CLONE_THREAD).
(13) nfsd.
The NFS server daemon now has to use the COW credentials to set the
credentials it is going to use. It really needs to pass the credentials
down to the functions it calls, but it can't do that until other patches
in this series have been applied.
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: James Morris <jmorris@namei.org>
Signed-off-by: James Morris <jmorris@namei.org>
2008-11-13 23:39:23 +00:00
|
|
|
/*
|
|
|
|
* initialise the security for the init task
|
|
|
|
*/
|
|
|
|
static void cred_init_security(void)
|
2005-04-16 22:20:36 +00:00
|
|
|
{
|
2008-11-13 23:39:26 +00:00
|
|
|
struct cred *cred = (struct cred *) current->real_cred;
|
2005-04-16 22:20:36 +00:00
|
|
|
struct task_security_struct *tsec;
|
|
|
|
|
2005-10-30 22:59:21 +00:00
|
|
|
tsec = kzalloc(sizeof(struct task_security_struct), GFP_KERNEL);
|
2005-04-16 22:20:36 +00:00
|
|
|
if (!tsec)
|
CRED: Inaugurate COW credentials
Inaugurate copy-on-write credentials management. This uses RCU to manage the
credentials pointer in the task_struct with respect to accesses by other tasks.
A process may only modify its own credentials, and so does not need locking to
access or modify its own credentials.
A mutex (cred_replace_mutex) is added to the task_struct to control the effect
of PTRACE_ATTACHED on credential calculations, particularly with respect to
execve().
With this patch, the contents of an active credentials struct may not be
changed directly; rather a new set of credentials must be prepared, modified
and committed using something like the following sequence of events:
struct cred *new = prepare_creds();
int ret = blah(new);
if (ret < 0) {
abort_creds(new);
return ret;
}
return commit_creds(new);
There are some exceptions to this rule: the keyrings pointed to by the active
credentials may be instantiated - keyrings violate the COW rule as managing
COW keyrings is tricky, given that it is possible for a task to directly alter
the keys in a keyring in use by another task.
To help enforce this, various pointers to sets of credentials, such as those in
the task_struct, are declared const. The purpose of this is compile-time
discouragement of altering credentials through those pointers. Once a set of
credentials has been made public through one of these pointers, it may not be
modified, except under special circumstances:
(1) Its reference count may incremented and decremented.
(2) The keyrings to which it points may be modified, but not replaced.
The only safe way to modify anything else is to create a replacement and commit
using the functions described in Documentation/credentials.txt (which will be
added by a later patch).
This patch and the preceding patches have been tested with the LTP SELinux
testsuite.
This patch makes several logical sets of alteration:
(1) execve().
This now prepares and commits credentials in various places in the
security code rather than altering the current creds directly.
(2) Temporary credential overrides.
do_coredump() and sys_faccessat() now prepare their own credentials and
temporarily override the ones currently on the acting thread, whilst
preventing interference from other threads by holding cred_replace_mutex
on the thread being dumped.
This will be replaced in a future patch by something that hands down the
credentials directly to the functions being called, rather than altering
the task's objective credentials.
(3) LSM interface.
A number of functions have been changed, added or removed:
(*) security_capset_check(), ->capset_check()
(*) security_capset_set(), ->capset_set()
Removed in favour of security_capset().
(*) security_capset(), ->capset()
New. This is passed a pointer to the new creds, a pointer to the old
creds and the proposed capability sets. It should fill in the new
creds or return an error. All pointers, barring the pointer to the
new creds, are now const.
(*) security_bprm_apply_creds(), ->bprm_apply_creds()
Changed; now returns a value, which will cause the process to be
killed if it's an error.
(*) security_task_alloc(), ->task_alloc_security()
Removed in favour of security_prepare_creds().
(*) security_cred_free(), ->cred_free()
New. Free security data attached to cred->security.
(*) security_prepare_creds(), ->cred_prepare()
New. Duplicate any security data attached to cred->security.
(*) security_commit_creds(), ->cred_commit()
New. Apply any security effects for the upcoming installation of new
security by commit_creds().
(*) security_task_post_setuid(), ->task_post_setuid()
Removed in favour of security_task_fix_setuid().
(*) security_task_fix_setuid(), ->task_fix_setuid()
Fix up the proposed new credentials for setuid(). This is used by
cap_set_fix_setuid() to implicitly adjust capabilities in line with
setuid() changes. Changes are made to the new credentials, rather
than the task itself as in security_task_post_setuid().
(*) security_task_reparent_to_init(), ->task_reparent_to_init()
Removed. Instead the task being reparented to init is referred
directly to init's credentials.
NOTE! This results in the loss of some state: SELinux's osid no
longer records the sid of the thread that forked it.
(*) security_key_alloc(), ->key_alloc()
(*) security_key_permission(), ->key_permission()
Changed. These now take cred pointers rather than task pointers to
refer to the security context.
(4) sys_capset().
This has been simplified and uses less locking. The LSM functions it
calls have been merged.
(5) reparent_to_kthreadd().
This gives the current thread the same credentials as init by simply using
commit_thread() to point that way.
(6) __sigqueue_alloc() and switch_uid()
__sigqueue_alloc() can't stop the target task from changing its creds
beneath it, so this function gets a reference to the currently applicable
user_struct which it then passes into the sigqueue struct it returns if
successful.
switch_uid() is now called from commit_creds(), and possibly should be
folded into that. commit_creds() should take care of protecting
__sigqueue_alloc().
(7) [sg]et[ug]id() and co and [sg]et_current_groups.
The set functions now all use prepare_creds(), commit_creds() and
abort_creds() to build and check a new set of credentials before applying
it.
security_task_set[ug]id() is called inside the prepared section. This
guarantees that nothing else will affect the creds until we've finished.
The calling of set_dumpable() has been moved into commit_creds().
Much of the functionality of set_user() has been moved into
commit_creds().
The get functions all simply access the data directly.
(8) security_task_prctl() and cap_task_prctl().
security_task_prctl() has been modified to return -ENOSYS if it doesn't
want to handle a function, or otherwise return the return value directly
rather than through an argument.
Additionally, cap_task_prctl() now prepares a new set of credentials, even
if it doesn't end up using it.
(9) Keyrings.
A number of changes have been made to the keyrings code:
(a) switch_uid_keyring(), copy_keys(), exit_keys() and suid_keys() have
all been dropped and built in to the credentials functions directly.
They may want separating out again later.
(b) key_alloc() and search_process_keyrings() now take a cred pointer
rather than a task pointer to specify the security context.
(c) copy_creds() gives a new thread within the same thread group a new
thread keyring if its parent had one, otherwise it discards the thread
keyring.
(d) The authorisation key now points directly to the credentials to extend
the search into rather pointing to the task that carries them.
(e) Installing thread, process or session keyrings causes a new set of
credentials to be created, even though it's not strictly necessary for
process or session keyrings (they're shared).
(10) Usermode helper.
The usermode helper code now carries a cred struct pointer in its
subprocess_info struct instead of a new session keyring pointer. This set
of credentials is derived from init_cred and installed on the new process
after it has been cloned.
call_usermodehelper_setup() allocates the new credentials and
call_usermodehelper_freeinfo() discards them if they haven't been used. A
special cred function (prepare_usermodeinfo_creds()) is provided
specifically for call_usermodehelper_setup() to call.
call_usermodehelper_setkeys() adjusts the credentials to sport the
supplied keyring as the new session keyring.
(11) SELinux.
SELinux has a number of changes, in addition to those to support the LSM
interface changes mentioned above:
(a) selinux_setprocattr() no longer does its check for whether the
current ptracer can access processes with the new SID inside the lock
that covers getting the ptracer's SID. Whilst this lock ensures that
the check is done with the ptracer pinned, the result is only valid
until the lock is released, so there's no point doing it inside the
lock.
(12) is_single_threaded().
This function has been extracted from selinux_setprocattr() and put into
a file of its own in the lib/ directory as join_session_keyring() now
wants to use it too.
The code in SELinux just checked to see whether a task shared mm_structs
with other tasks (CLONE_VM), but that isn't good enough. We really want
to know if they're part of the same thread group (CLONE_THREAD).
(13) nfsd.
The NFS server daemon now has to use the COW credentials to set the
credentials it is going to use. It really needs to pass the credentials
down to the functions it calls, but it can't do that until other patches
in this series have been applied.
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: James Morris <jmorris@namei.org>
Signed-off-by: James Morris <jmorris@namei.org>
2008-11-13 23:39:23 +00:00
|
|
|
panic("SELinux: Failed to initialize initial task.\n");
|
2005-04-16 22:20:36 +00:00
|
|
|
|
CRED: Inaugurate COW credentials
Inaugurate copy-on-write credentials management. This uses RCU to manage the
credentials pointer in the task_struct with respect to accesses by other tasks.
A process may only modify its own credentials, and so does not need locking to
access or modify its own credentials.
A mutex (cred_replace_mutex) is added to the task_struct to control the effect
of PTRACE_ATTACHED on credential calculations, particularly with respect to
execve().
With this patch, the contents of an active credentials struct may not be
changed directly; rather a new set of credentials must be prepared, modified
and committed using something like the following sequence of events:
struct cred *new = prepare_creds();
int ret = blah(new);
if (ret < 0) {
abort_creds(new);
return ret;
}
return commit_creds(new);
There are some exceptions to this rule: the keyrings pointed to by the active
credentials may be instantiated - keyrings violate the COW rule as managing
COW keyrings is tricky, given that it is possible for a task to directly alter
the keys in a keyring in use by another task.
To help enforce this, various pointers to sets of credentials, such as those in
the task_struct, are declared const. The purpose of this is compile-time
discouragement of altering credentials through those pointers. Once a set of
credentials has been made public through one of these pointers, it may not be
modified, except under special circumstances:
(1) Its reference count may incremented and decremented.
(2) The keyrings to which it points may be modified, but not replaced.
The only safe way to modify anything else is to create a replacement and commit
using the functions described in Documentation/credentials.txt (which will be
added by a later patch).
This patch and the preceding patches have been tested with the LTP SELinux
testsuite.
This patch makes several logical sets of alteration:
(1) execve().
This now prepares and commits credentials in various places in the
security code rather than altering the current creds directly.
(2) Temporary credential overrides.
do_coredump() and sys_faccessat() now prepare their own credentials and
temporarily override the ones currently on the acting thread, whilst
preventing interference from other threads by holding cred_replace_mutex
on the thread being dumped.
This will be replaced in a future patch by something that hands down the
credentials directly to the functions being called, rather than altering
the task's objective credentials.
(3) LSM interface.
A number of functions have been changed, added or removed:
(*) security_capset_check(), ->capset_check()
(*) security_capset_set(), ->capset_set()
Removed in favour of security_capset().
(*) security_capset(), ->capset()
New. This is passed a pointer to the new creds, a pointer to the old
creds and the proposed capability sets. It should fill in the new
creds or return an error. All pointers, barring the pointer to the
new creds, are now const.
(*) security_bprm_apply_creds(), ->bprm_apply_creds()
Changed; now returns a value, which will cause the process to be
killed if it's an error.
(*) security_task_alloc(), ->task_alloc_security()
Removed in favour of security_prepare_creds().
(*) security_cred_free(), ->cred_free()
New. Free security data attached to cred->security.
(*) security_prepare_creds(), ->cred_prepare()
New. Duplicate any security data attached to cred->security.
(*) security_commit_creds(), ->cred_commit()
New. Apply any security effects for the upcoming installation of new
security by commit_creds().
(*) security_task_post_setuid(), ->task_post_setuid()
Removed in favour of security_task_fix_setuid().
(*) security_task_fix_setuid(), ->task_fix_setuid()
Fix up the proposed new credentials for setuid(). This is used by
cap_set_fix_setuid() to implicitly adjust capabilities in line with
setuid() changes. Changes are made to the new credentials, rather
than the task itself as in security_task_post_setuid().
(*) security_task_reparent_to_init(), ->task_reparent_to_init()
Removed. Instead the task being reparented to init is referred
directly to init's credentials.
NOTE! This results in the loss of some state: SELinux's osid no
longer records the sid of the thread that forked it.
(*) security_key_alloc(), ->key_alloc()
(*) security_key_permission(), ->key_permission()
Changed. These now take cred pointers rather than task pointers to
refer to the security context.
(4) sys_capset().
This has been simplified and uses less locking. The LSM functions it
calls have been merged.
(5) reparent_to_kthreadd().
This gives the current thread the same credentials as init by simply using
commit_thread() to point that way.
(6) __sigqueue_alloc() and switch_uid()
__sigqueue_alloc() can't stop the target task from changing its creds
beneath it, so this function gets a reference to the currently applicable
user_struct which it then passes into the sigqueue struct it returns if
successful.
switch_uid() is now called from commit_creds(), and possibly should be
folded into that. commit_creds() should take care of protecting
__sigqueue_alloc().
(7) [sg]et[ug]id() and co and [sg]et_current_groups.
The set functions now all use prepare_creds(), commit_creds() and
abort_creds() to build and check a new set of credentials before applying
it.
security_task_set[ug]id() is called inside the prepared section. This
guarantees that nothing else will affect the creds until we've finished.
The calling of set_dumpable() has been moved into commit_creds().
Much of the functionality of set_user() has been moved into
commit_creds().
The get functions all simply access the data directly.
(8) security_task_prctl() and cap_task_prctl().
security_task_prctl() has been modified to return -ENOSYS if it doesn't
want to handle a function, or otherwise return the return value directly
rather than through an argument.
Additionally, cap_task_prctl() now prepares a new set of credentials, even
if it doesn't end up using it.
(9) Keyrings.
A number of changes have been made to the keyrings code:
(a) switch_uid_keyring(), copy_keys(), exit_keys() and suid_keys() have
all been dropped and built in to the credentials functions directly.
They may want separating out again later.
(b) key_alloc() and search_process_keyrings() now take a cred pointer
rather than a task pointer to specify the security context.
(c) copy_creds() gives a new thread within the same thread group a new
thread keyring if its parent had one, otherwise it discards the thread
keyring.
(d) The authorisation key now points directly to the credentials to extend
the search into rather pointing to the task that carries them.
(e) Installing thread, process or session keyrings causes a new set of
credentials to be created, even though it's not strictly necessary for
process or session keyrings (they're shared).
(10) Usermode helper.
The usermode helper code now carries a cred struct pointer in its
subprocess_info struct instead of a new session keyring pointer. This set
of credentials is derived from init_cred and installed on the new process
after it has been cloned.
call_usermodehelper_setup() allocates the new credentials and
call_usermodehelper_freeinfo() discards them if they haven't been used. A
special cred function (prepare_usermodeinfo_creds()) is provided
specifically for call_usermodehelper_setup() to call.
call_usermodehelper_setkeys() adjusts the credentials to sport the
supplied keyring as the new session keyring.
(11) SELinux.
SELinux has a number of changes, in addition to those to support the LSM
interface changes mentioned above:
(a) selinux_setprocattr() no longer does its check for whether the
current ptracer can access processes with the new SID inside the lock
that covers getting the ptracer's SID. Whilst this lock ensures that
the check is done with the ptracer pinned, the result is only valid
until the lock is released, so there's no point doing it inside the
lock.
(12) is_single_threaded().
This function has been extracted from selinux_setprocattr() and put into
a file of its own in the lib/ directory as join_session_keyring() now
wants to use it too.
The code in SELinux just checked to see whether a task shared mm_structs
with other tasks (CLONE_VM), but that isn't good enough. We really want
to know if they're part of the same thread group (CLONE_THREAD).
(13) nfsd.
The NFS server daemon now has to use the COW credentials to set the
credentials it is going to use. It really needs to pass the credentials
down to the functions it calls, but it can't do that until other patches
in this series have been applied.
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: James Morris <jmorris@namei.org>
Signed-off-by: James Morris <jmorris@namei.org>
2008-11-13 23:39:23 +00:00
|
|
|
tsec->osid = tsec->sid = SECINITSID_KERNEL;
|
2008-11-13 23:39:17 +00:00
|
|
|
cred->security = tsec;
|
2005-04-16 22:20:36 +00:00
|
|
|
}
|
|
|
|
|
2008-11-13 23:39:21 +00:00
|
|
|
/*
|
|
|
|
* get the security ID of a set of credentials
|
|
|
|
*/
|
|
|
|
static inline u32 cred_sid(const struct cred *cred)
|
|
|
|
{
|
|
|
|
const struct task_security_struct *tsec;
|
|
|
|
|
|
|
|
tsec = cred->security;
|
|
|
|
return tsec->sid;
|
|
|
|
}
|
|
|
|
|
2008-11-13 23:39:19 +00:00
|
|
|
/*
|
2008-11-13 23:39:26 +00:00
|
|
|
* get the objective security ID of a task
|
2008-11-13 23:39:19 +00:00
|
|
|
*/
|
|
|
|
static inline u32 task_sid(const struct task_struct *task)
|
|
|
|
{
|
|
|
|
u32 sid;
|
|
|
|
|
|
|
|
rcu_read_lock();
|
2008-11-13 23:39:21 +00:00
|
|
|
sid = cred_sid(__task_cred(task));
|
2008-11-13 23:39:19 +00:00
|
|
|
rcu_read_unlock();
|
|
|
|
return sid;
|
|
|
|
}
|
|
|
|
|
|
|
|
/*
|
2008-11-13 23:39:26 +00:00
|
|
|
* get the subjective security ID of the current task
|
2008-11-13 23:39:19 +00:00
|
|
|
*/
|
|
|
|
static inline u32 current_sid(void)
|
|
|
|
{
|
2010-04-22 18:46:19 +00:00
|
|
|
const struct task_security_struct *tsec = current_security();
|
2008-11-13 23:39:19 +00:00
|
|
|
|
|
|
|
return tsec->sid;
|
|
|
|
}
|
|
|
|
|
2008-11-13 23:39:21 +00:00
|
|
|
/* Allocate and free functions for each kind of security blob. */
|
|
|
|
|
2005-04-16 22:20:36 +00:00
|
|
|
static int inode_alloc_security(struct inode *inode)
|
|
|
|
{
|
|
|
|
struct inode_security_struct *isec;
|
2008-11-13 23:39:19 +00:00
|
|
|
u32 sid = current_sid();
|
2005-04-16 22:20:36 +00:00
|
|
|
|
2008-04-03 22:35:05 +00:00
|
|
|
isec = kmem_cache_zalloc(sel_inode_cache, GFP_NOFS);
|
2005-04-16 22:20:36 +00:00
|
|
|
if (!isec)
|
|
|
|
return -ENOMEM;
|
|
|
|
|
2006-09-26 06:32:01 +00:00
|
|
|
mutex_init(&isec->lock);
|
2005-04-16 22:20:36 +00:00
|
|
|
INIT_LIST_HEAD(&isec->list);
|
|
|
|
isec->inode = inode;
|
|
|
|
isec->sid = SECINITSID_UNLABELED;
|
|
|
|
isec->sclass = SECCLASS_FILE;
|
2008-11-13 23:39:19 +00:00
|
|
|
isec->task_sid = sid;
|
2005-04-16 22:20:36 +00:00
|
|
|
inode->i_security = isec;
|
|
|
|
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
SELinux: Fix possible NULL pointer dereference in selinux_inode_permission()
While running stress tests on adding and deleting ftrace instances I hit
this bug:
BUG: unable to handle kernel NULL pointer dereference at 0000000000000020
IP: selinux_inode_permission+0x85/0x160
PGD 63681067 PUD 7ddbe067 PMD 0
Oops: 0000 [#1] PREEMPT
CPU: 0 PID: 5634 Comm: ftrace-test-mki Not tainted 3.13.0-rc4-test-00033-gd2a6dde-dirty #20
Hardware name: /DG965MQ, BIOS MQ96510J.86A.0372.2006.0605.1717 06/05/2006
task: ffff880078375800 ti: ffff88007ddb0000 task.ti: ffff88007ddb0000
RIP: 0010:[<ffffffff812d8bc5>] [<ffffffff812d8bc5>] selinux_inode_permission+0x85/0x160
RSP: 0018:ffff88007ddb1c48 EFLAGS: 00010246
RAX: 0000000000000000 RBX: 0000000000800000 RCX: ffff88006dd43840
RDX: 0000000000000001 RSI: 0000000000000081 RDI: ffff88006ee46000
RBP: ffff88007ddb1c88 R08: 0000000000000000 R09: ffff88007ddb1c54
R10: 6e6576652f6f6f66 R11: 0000000000000003 R12: 0000000000000000
R13: 0000000000000081 R14: ffff88006ee46000 R15: 0000000000000000
FS: 00007f217b5b6700(0000) GS:ffffffff81e21000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033^M
CR2: 0000000000000020 CR3: 000000006a0fe000 CR4: 00000000000007f0
Call Trace:
security_inode_permission+0x1c/0x30
__inode_permission+0x41/0xa0
inode_permission+0x18/0x50
link_path_walk+0x66/0x920
path_openat+0xa6/0x6c0
do_filp_open+0x43/0xa0
do_sys_open+0x146/0x240
SyS_open+0x1e/0x20
system_call_fastpath+0x16/0x1b
Code: 84 a1 00 00 00 81 e3 00 20 00 00 89 d8 83 c8 02 40 f6 c6 04 0f 45 d8 40 f6 c6 08 74 71 80 cf 02 49 8b 46 38 4c 8d 4d cc 45 31 c0 <0f> b7 50 20 8b 70 1c 48 8b 41 70 89 d9 8b 78 04 e8 36 cf ff ff
RIP selinux_inode_permission+0x85/0x160
CR2: 0000000000000020
Investigating, I found that the inode->i_security was NULL, and the
dereference of it caused the oops.
in selinux_inode_permission():
isec = inode->i_security;
rc = avc_has_perm_noaudit(sid, isec->sid, isec->sclass, perms, 0, &avd);
Note, the crash came from stressing the deletion and reading of debugfs
files. I was not able to recreate this via normal files. But I'm not
sure they are safe. It may just be that the race window is much harder
to hit.
What seems to have happened (and what I have traced), is the file is
being opened at the same time the file or directory is being deleted.
As the dentry and inode locks are not held during the path walk, nor is
the inodes ref counts being incremented, there is nothing saving these
structures from being discarded except for an rcu_read_lock().
The rcu_read_lock() protects against freeing of the inode, but it does
not protect freeing of the inode_security_struct. Now if the freeing of
the i_security happens with a call_rcu(), and the i_security field of
the inode is not changed (it gets freed as the inode gets freed) then
there will be no issue here. (Linus Torvalds suggested not setting the
field to NULL such that we do not need to check if it is NULL in the
permission check).
Note, this is a hack, but it fixes the problem at hand. A real fix is
to restructure the destroy_inode() to call all the destructor handlers
from the RCU callback. But that is a major job to do, and requires a
lot of work. For now, we just band-aid this bug with this fix (it
works), and work on a more maintainable solution in the future.
Link: http://lkml.kernel.org/r/20140109101932.0508dec7@gandalf.local.home
Link: http://lkml.kernel.org/r/20140109182756.17abaaa8@gandalf.local.home
Cc: stable@vger.kernel.org
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-01-10 02:46:34 +00:00
|
|
|
static void inode_free_rcu(struct rcu_head *head)
|
|
|
|
{
|
|
|
|
struct inode_security_struct *isec;
|
|
|
|
|
|
|
|
isec = container_of(head, struct inode_security_struct, rcu);
|
|
|
|
kmem_cache_free(sel_inode_cache, isec);
|
|
|
|
}
|
|
|
|
|
2005-04-16 22:20:36 +00:00
|
|
|
static void inode_free_security(struct inode *inode)
|
|
|
|
{
|
|
|
|
struct inode_security_struct *isec = inode->i_security;
|
|
|
|
struct superblock_security_struct *sbsec = inode->i_sb->s_security;
|
|
|
|
|
|
|
|
spin_lock(&sbsec->isec_lock);
|
|
|
|
if (!list_empty(&isec->list))
|
|
|
|
list_del_init(&isec->list);
|
|
|
|
spin_unlock(&sbsec->isec_lock);
|
|
|
|
|
SELinux: Fix possible NULL pointer dereference in selinux_inode_permission()
While running stress tests on adding and deleting ftrace instances I hit
this bug:
BUG: unable to handle kernel NULL pointer dereference at 0000000000000020
IP: selinux_inode_permission+0x85/0x160
PGD 63681067 PUD 7ddbe067 PMD 0
Oops: 0000 [#1] PREEMPT
CPU: 0 PID: 5634 Comm: ftrace-test-mki Not tainted 3.13.0-rc4-test-00033-gd2a6dde-dirty #20
Hardware name: /DG965MQ, BIOS MQ96510J.86A.0372.2006.0605.1717 06/05/2006
task: ffff880078375800 ti: ffff88007ddb0000 task.ti: ffff88007ddb0000
RIP: 0010:[<ffffffff812d8bc5>] [<ffffffff812d8bc5>] selinux_inode_permission+0x85/0x160
RSP: 0018:ffff88007ddb1c48 EFLAGS: 00010246
RAX: 0000000000000000 RBX: 0000000000800000 RCX: ffff88006dd43840
RDX: 0000000000000001 RSI: 0000000000000081 RDI: ffff88006ee46000
RBP: ffff88007ddb1c88 R08: 0000000000000000 R09: ffff88007ddb1c54
R10: 6e6576652f6f6f66 R11: 0000000000000003 R12: 0000000000000000
R13: 0000000000000081 R14: ffff88006ee46000 R15: 0000000000000000
FS: 00007f217b5b6700(0000) GS:ffffffff81e21000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033^M
CR2: 0000000000000020 CR3: 000000006a0fe000 CR4: 00000000000007f0
Call Trace:
security_inode_permission+0x1c/0x30
__inode_permission+0x41/0xa0
inode_permission+0x18/0x50
link_path_walk+0x66/0x920
path_openat+0xa6/0x6c0
do_filp_open+0x43/0xa0
do_sys_open+0x146/0x240
SyS_open+0x1e/0x20
system_call_fastpath+0x16/0x1b
Code: 84 a1 00 00 00 81 e3 00 20 00 00 89 d8 83 c8 02 40 f6 c6 04 0f 45 d8 40 f6 c6 08 74 71 80 cf 02 49 8b 46 38 4c 8d 4d cc 45 31 c0 <0f> b7 50 20 8b 70 1c 48 8b 41 70 89 d9 8b 78 04 e8 36 cf ff ff
RIP selinux_inode_permission+0x85/0x160
CR2: 0000000000000020
Investigating, I found that the inode->i_security was NULL, and the
dereference of it caused the oops.
in selinux_inode_permission():
isec = inode->i_security;
rc = avc_has_perm_noaudit(sid, isec->sid, isec->sclass, perms, 0, &avd);
Note, the crash came from stressing the deletion and reading of debugfs
files. I was not able to recreate this via normal files. But I'm not
sure they are safe. It may just be that the race window is much harder
to hit.
What seems to have happened (and what I have traced), is the file is
being opened at the same time the file or directory is being deleted.
As the dentry and inode locks are not held during the path walk, nor is
the inodes ref counts being incremented, there is nothing saving these
structures from being discarded except for an rcu_read_lock().
The rcu_read_lock() protects against freeing of the inode, but it does
not protect freeing of the inode_security_struct. Now if the freeing of
the i_security happens with a call_rcu(), and the i_security field of
the inode is not changed (it gets freed as the inode gets freed) then
there will be no issue here. (Linus Torvalds suggested not setting the
field to NULL such that we do not need to check if it is NULL in the
permission check).
Note, this is a hack, but it fixes the problem at hand. A real fix is
to restructure the destroy_inode() to call all the destructor handlers
from the RCU callback. But that is a major job to do, and requires a
lot of work. For now, we just band-aid this bug with this fix (it
works), and work on a more maintainable solution in the future.
Link: http://lkml.kernel.org/r/20140109101932.0508dec7@gandalf.local.home
Link: http://lkml.kernel.org/r/20140109182756.17abaaa8@gandalf.local.home
Cc: stable@vger.kernel.org
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-01-10 02:46:34 +00:00
|
|
|
/*
|
|
|
|
* The inode may still be referenced in a path walk and
|
|
|
|
* a call to selinux_inode_permission() can be made
|
|
|
|
* after inode_free_security() is called. Ideally, the VFS
|
|
|
|
* wouldn't do this, but fixing that is a much harder
|
|
|
|
* job. For now, simply free the i_security via RCU, and
|
|
|
|
* leave the current inode->i_security pointer intact.
|
|
|
|
* The inode will be freed after the RCU grace period too.
|
|
|
|
*/
|
|
|
|
call_rcu(&isec->rcu, inode_free_rcu);
|
2005-04-16 22:20:36 +00:00
|
|
|
}
|
|
|
|
|
|
|
|
static int file_alloc_security(struct file *file)
|
|
|
|
{
|
|
|
|
struct file_security_struct *fsec;
|
2008-11-13 23:39:19 +00:00
|
|
|
u32 sid = current_sid();
|
2005-04-16 22:20:36 +00:00
|
|
|
|
2006-02-01 11:05:55 +00:00
|
|
|
fsec = kzalloc(sizeof(struct file_security_struct), GFP_KERNEL);
|
2005-04-16 22:20:36 +00:00
|
|
|
if (!fsec)
|
|
|
|
return -ENOMEM;
|
|
|
|
|
2008-11-13 23:39:19 +00:00
|
|
|
fsec->sid = sid;
|
|
|
|
fsec->fown_sid = sid;
|
2005-04-16 22:20:36 +00:00
|
|
|
file->f_security = fsec;
|
|
|
|
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
|
|
|
static void file_free_security(struct file *file)
|
|
|
|
{
|
|
|
|
struct file_security_struct *fsec = file->f_security;
|
|
|
|
file->f_security = NULL;
|
|
|
|
kfree(fsec);
|
|
|
|
}
|
|
|
|
|
|
|
|
static int superblock_alloc_security(struct super_block *sb)
|
|
|
|
{
|
|
|
|
struct superblock_security_struct *sbsec;
|
|
|
|
|
2005-10-30 22:59:21 +00:00
|
|
|
sbsec = kzalloc(sizeof(struct superblock_security_struct), GFP_KERNEL);
|
2005-04-16 22:20:36 +00:00
|
|
|
if (!sbsec)
|
|
|
|
return -ENOMEM;
|
|
|
|
|
2006-09-26 06:32:02 +00:00
|
|
|
mutex_init(&sbsec->lock);
|
2005-04-16 22:20:36 +00:00
|
|
|
INIT_LIST_HEAD(&sbsec->isec_head);
|
|
|
|
spin_lock_init(&sbsec->isec_lock);
|
|
|
|
sbsec->sb = sb;
|
|
|
|
sbsec->sid = SECINITSID_UNLABELED;
|
|
|
|
sbsec->def_sid = SECINITSID_FILE;
|
2006-07-10 11:43:53 +00:00
|
|
|
sbsec->mntpoint_sid = SECINITSID_UNLABELED;
|
2005-04-16 22:20:36 +00:00
|
|
|
sb->s_security = sbsec;
|
|
|
|
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
|
|
|
static void superblock_free_security(struct super_block *sb)
|
|
|
|
{
|
|
|
|
struct superblock_security_struct *sbsec = sb->s_security;
|
|
|
|
sb->s_security = NULL;
|
|
|
|
kfree(sbsec);
|
|
|
|
}
|
|
|
|
|
|
|
|
/* The file system's label must be initialized prior to use. */
|
|
|
|
|
2013-05-22 16:50:37 +00:00
|
|
|
static const char *labeling_behaviors[7] = {
|
2005-04-16 22:20:36 +00:00
|
|
|
"uses xattr",
|
|
|
|
"uses transition SIDs",
|
|
|
|
"uses task SIDs",
|
|
|
|
"uses genfs_contexts",
|
|
|
|
"not configured for labeling",
|
|
|
|
"uses mountpoint labeling",
|
2013-05-22 16:50:37 +00:00
|
|
|
"uses native labeling",
|
2005-04-16 22:20:36 +00:00
|
|
|
};
|
|
|
|
|
|
|
|
static int inode_doinit_with_dentry(struct inode *inode, struct dentry *opt_dentry);
|
|
|
|
|
|
|
|
static inline int inode_doinit(struct inode *inode)
|
|
|
|
{
|
|
|
|
return inode_doinit_with_dentry(inode, NULL);
|
|
|
|
}
|
|
|
|
|
|
|
|
enum {
|
2007-09-19 21:19:12 +00:00
|
|
|
Opt_error = -1,
|
2005-04-16 22:20:36 +00:00
|
|
|
Opt_context = 1,
|
|
|
|
Opt_fscontext = 2,
|
2007-11-30 18:00:35 +00:00
|
|
|
Opt_defcontext = 3,
|
|
|
|
Opt_rootcontext = 4,
|
2009-01-16 14:22:03 +00:00
|
|
|
Opt_labelsupport = 5,
|
2012-08-24 19:58:53 +00:00
|
|
|
Opt_nextmntopt = 6,
|
2005-04-16 22:20:36 +00:00
|
|
|
};
|
|
|
|
|
2012-08-24 19:58:53 +00:00
|
|
|
#define NUM_SEL_MNT_OPTS (Opt_nextmntopt - 1)
|
|
|
|
|
2008-10-13 09:46:57 +00:00
|
|
|
static const match_table_t tokens = {
|
2008-04-01 17:24:09 +00:00
|
|
|
{Opt_context, CONTEXT_STR "%s"},
|
|
|
|
{Opt_fscontext, FSCONTEXT_STR "%s"},
|
|
|
|
{Opt_defcontext, DEFCONTEXT_STR "%s"},
|
|
|
|
{Opt_rootcontext, ROOTCONTEXT_STR "%s"},
|
2009-01-16 14:22:03 +00:00
|
|
|
{Opt_labelsupport, LABELSUPP_STR},
|
2007-09-19 21:19:12 +00:00
|
|
|
{Opt_error, NULL},
|
2005-04-16 22:20:36 +00:00
|
|
|
};
|
|
|
|
|
|
|
|
#define SEL_MOUNT_FAIL_MSG "SELinux: duplicate or incompatible mount options\n"
|
|
|
|
|
2006-07-10 11:43:53 +00:00
|
|
|
static int may_context_mount_sb_relabel(u32 sid,
|
|
|
|
struct superblock_security_struct *sbsec,
|
2008-11-13 23:39:19 +00:00
|
|
|
const struct cred *cred)
|
2006-07-10 11:43:53 +00:00
|
|
|
{
|
2008-11-13 23:39:19 +00:00
|
|
|
const struct task_security_struct *tsec = cred->security;
|
2006-07-10 11:43:53 +00:00
|
|
|
int rc;
|
|
|
|
|
|
|
|
rc = avc_has_perm(tsec->sid, sbsec->sid, SECCLASS_FILESYSTEM,
|
|
|
|
FILESYSTEM__RELABELFROM, NULL);
|
|
|
|
if (rc)
|
|
|
|
return rc;
|
|
|
|
|
|
|
|
rc = avc_has_perm(tsec->sid, sid, SECCLASS_FILESYSTEM,
|
|
|
|
FILESYSTEM__RELABELTO, NULL);
|
|
|
|
return rc;
|
|
|
|
}
|
|
|
|
|
2006-07-10 11:43:55 +00:00
|
|
|
static int may_context_mount_inode_relabel(u32 sid,
|
|
|
|
struct superblock_security_struct *sbsec,
|
2008-11-13 23:39:19 +00:00
|
|
|
const struct cred *cred)
|
2006-07-10 11:43:55 +00:00
|
|
|
{
|
2008-11-13 23:39:19 +00:00
|
|
|
const struct task_security_struct *tsec = cred->security;
|
2006-07-10 11:43:55 +00:00
|
|
|
int rc;
|
|
|
|
rc = avc_has_perm(tsec->sid, sbsec->sid, SECCLASS_FILESYSTEM,
|
|
|
|
FILESYSTEM__RELABELFROM, NULL);
|
|
|
|
if (rc)
|
|
|
|
return rc;
|
|
|
|
|
|
|
|
rc = avc_has_perm(sid, sbsec->sid, SECCLASS_FILESYSTEM,
|
|
|
|
FILESYSTEM__ASSOCIATE, NULL);
|
|
|
|
return rc;
|
|
|
|
}
|
|
|
|
|
2012-10-10 18:27:35 +00:00
|
|
|
static int selinux_is_sblabel_mnt(struct super_block *sb)
|
|
|
|
{
|
|
|
|
struct superblock_security_struct *sbsec = sb->s_security;
|
|
|
|
|
|
|
|
if (sbsec->behavior == SECURITY_FS_USE_XATTR ||
|
|
|
|
sbsec->behavior == SECURITY_FS_USE_TRANS ||
|
|
|
|
sbsec->behavior == SECURITY_FS_USE_TASK)
|
|
|
|
return 1;
|
|
|
|
|
|
|
|
/* Special handling for sysfs. Is genfs but also has setxattr handler*/
|
|
|
|
if (strncmp(sb->s_type->name, "sysfs", sizeof("sysfs")) == 0)
|
|
|
|
return 1;
|
|
|
|
|
|
|
|
/*
|
|
|
|
* Special handling for rootfs. Is genfs but supports
|
|
|
|
* setting SELinux context on in-core inodes.
|
|
|
|
*/
|
|
|
|
if (strncmp(sb->s_type->name, "rootfs", sizeof("rootfs")) == 0)
|
|
|
|
return 1;
|
|
|
|
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
2007-11-30 18:00:35 +00:00
|
|
|
static int sb_finish_set_opts(struct super_block *sb)
|
2005-04-16 22:20:36 +00:00
|
|
|
{
|
|
|
|
struct superblock_security_struct *sbsec = sb->s_security;
|
2007-11-30 18:00:35 +00:00
|
|
|
struct dentry *root = sb->s_root;
|
|
|
|
struct inode *root_inode = root->d_inode;
|
|
|
|
int rc = 0;
|
2005-04-16 22:20:36 +00:00
|
|
|
|
2007-11-30 18:00:35 +00:00
|
|
|
if (sbsec->behavior == SECURITY_FS_USE_XATTR) {
|
|
|
|
/* Make sure that the xattr handler exists and that no
|
|
|
|
error other than -ENODATA is returned by getxattr on
|
|
|
|
the root directory. -ENODATA is ok, as this may be
|
|
|
|
the first boot of the SELinux kernel before we have
|
|
|
|
assigned xattr values to the filesystem. */
|
|
|
|
if (!root_inode->i_op->getxattr) {
|
2013-12-15 19:17:45 +00:00
|
|
|
printk(KERN_WARNING "SELinux: (dev %s, type %s) has no "
|
|
|
|
"xattr support\n", sb->s_id, sb->s_type->name);
|
2007-11-30 18:00:35 +00:00
|
|
|
rc = -EOPNOTSUPP;
|
|
|
|
goto out;
|
|
|
|
}
|
|
|
|
rc = root_inode->i_op->getxattr(root, XATTR_NAME_SELINUX, NULL, 0);
|
|
|
|
if (rc < 0 && rc != -ENODATA) {
|
|
|
|
if (rc == -EOPNOTSUPP)
|
|
|
|
printk(KERN_WARNING "SELinux: (dev %s, type "
|
2013-12-15 19:17:45 +00:00
|
|
|
"%s) has no security xattr handler\n",
|
|
|
|
sb->s_id, sb->s_type->name);
|
2007-11-30 18:00:35 +00:00
|
|
|
else
|
|
|
|
printk(KERN_WARNING "SELinux: (dev %s, type "
|
2013-12-15 19:17:45 +00:00
|
|
|
"%s) getxattr errno %d\n", sb->s_id,
|
|
|
|
sb->s_type->name, -rc);
|
2007-11-30 18:00:35 +00:00
|
|
|
goto out;
|
|
|
|
}
|
|
|
|
}
|
2005-04-16 22:20:36 +00:00
|
|
|
|
2007-11-30 18:00:35 +00:00
|
|
|
if (sbsec->behavior > ARRAY_SIZE(labeling_behaviors))
|
2013-12-15 19:17:45 +00:00
|
|
|
printk(KERN_ERR "SELinux: initialized (dev %s, type %s), unknown behavior\n",
|
|
|
|
sb->s_id, sb->s_type->name);
|
2007-11-30 18:00:35 +00:00
|
|
|
else
|
2013-12-15 19:17:45 +00:00
|
|
|
printk(KERN_DEBUG "SELinux: initialized (dev %s, type %s), %s\n",
|
|
|
|
sb->s_id, sb->s_type->name,
|
2007-11-30 18:00:35 +00:00
|
|
|
labeling_behaviors[sbsec->behavior-1]);
|
2005-04-16 22:20:36 +00:00
|
|
|
|
2012-08-24 19:59:14 +00:00
|
|
|
sbsec->flags |= SE_SBINITIALIZED;
|
2012-10-10 18:27:35 +00:00
|
|
|
if (selinux_is_sblabel_mnt(sb))
|
2012-10-09 14:56:25 +00:00
|
|
|
sbsec->flags |= SBLABEL_MNT;
|
2009-09-09 18:25:37 +00:00
|
|
|
|
2007-11-30 18:00:35 +00:00
|
|
|
/* Initialize the root inode. */
|
|
|
|
rc = inode_doinit_with_dentry(root_inode, root);
|
2005-04-16 22:20:36 +00:00
|
|
|
|
2007-11-30 18:00:35 +00:00
|
|
|
/* Initialize any other inodes associated with the superblock, e.g.
|
|
|
|
inodes created prior to initial policy load or inodes created
|
|
|
|
during get_sb by a pseudo filesystem that directly
|
|
|
|
populates itself. */
|
|
|
|
spin_lock(&sbsec->isec_lock);
|
|
|
|
next_inode:
|
|
|
|
if (!list_empty(&sbsec->isec_head)) {
|
|
|
|
struct inode_security_struct *isec =
|
|
|
|
list_entry(sbsec->isec_head.next,
|
|
|
|
struct inode_security_struct, list);
|
|
|
|
struct inode *inode = isec->inode;
|
|
|
|
spin_unlock(&sbsec->isec_lock);
|
|
|
|
inode = igrab(inode);
|
|
|
|
if (inode) {
|
|
|
|
if (!IS_PRIVATE(inode))
|
|
|
|
inode_doinit(inode);
|
|
|
|
iput(inode);
|
|
|
|
}
|
|
|
|
spin_lock(&sbsec->isec_lock);
|
|
|
|
list_del_init(&isec->list);
|
|
|
|
goto next_inode;
|
|
|
|
}
|
|
|
|
spin_unlock(&sbsec->isec_lock);
|
|
|
|
out:
|
|
|
|
return rc;
|
|
|
|
}
|
2005-04-16 22:20:36 +00:00
|
|
|
|
2007-11-30 18:00:35 +00:00
|
|
|
/*
|
|
|
|
* This function should allow an FS to ask what it's mount security
|
|
|
|
* options were so it can use those later for submounts, displaying
|
|
|
|
* mount options, or whatever.
|
|
|
|
*/
|
|
|
|
static int selinux_get_mnt_opts(const struct super_block *sb,
|
2008-03-05 15:31:54 +00:00
|
|
|
struct security_mnt_opts *opts)
|
2007-11-30 18:00:35 +00:00
|
|
|
{
|
|
|
|
int rc = 0, i;
|
|
|
|
struct superblock_security_struct *sbsec = sb->s_security;
|
|
|
|
char *context = NULL;
|
|
|
|
u32 len;
|
|
|
|
char tmp;
|
2005-04-16 22:20:36 +00:00
|
|
|
|
2008-03-05 15:31:54 +00:00
|
|
|
security_init_mnt_opts(opts);
|
2005-04-16 22:20:36 +00:00
|
|
|
|
2009-01-16 14:22:02 +00:00
|
|
|
if (!(sbsec->flags & SE_SBINITIALIZED))
|
2007-11-30 18:00:35 +00:00
|
|
|
return -EINVAL;
|
2005-04-16 22:20:36 +00:00
|
|
|
|
2007-11-30 18:00:35 +00:00
|
|
|
if (!ss_initialized)
|
|
|
|
return -EINVAL;
|
2005-04-16 22:20:36 +00:00
|
|
|
|
2012-08-24 19:59:00 +00:00
|
|
|
/* make sure we always check enough bits to cover the mask */
|
|
|
|
BUILD_BUG_ON(SE_MNTMASK >= (1 << NUM_SEL_MNT_OPTS));
|
|
|
|
|
2009-01-16 14:22:02 +00:00
|
|
|
tmp = sbsec->flags & SE_MNTMASK;
|
2007-11-30 18:00:35 +00:00
|
|
|
/* count the number of mount options for this sb */
|
2012-08-24 19:59:00 +00:00
|
|
|
for (i = 0; i < NUM_SEL_MNT_OPTS; i++) {
|
2007-11-30 18:00:35 +00:00
|
|
|
if (tmp & 0x01)
|
2008-03-05 15:31:54 +00:00
|
|
|
opts->num_mnt_opts++;
|
2007-11-30 18:00:35 +00:00
|
|
|
tmp >>= 1;
|
|
|
|
}
|
2009-01-16 14:22:03 +00:00
|
|
|
/* Check if the Label support flag is set */
|
2013-08-28 17:32:42 +00:00
|
|
|
if (sbsec->flags & SBLABEL_MNT)
|
2009-01-16 14:22:03 +00:00
|
|
|
opts->num_mnt_opts++;
|
2005-04-16 22:20:36 +00:00
|
|
|
|
2008-03-05 15:31:54 +00:00
|
|
|
opts->mnt_opts = kcalloc(opts->num_mnt_opts, sizeof(char *), GFP_ATOMIC);
|
|
|
|
if (!opts->mnt_opts) {
|
2007-11-30 18:00:35 +00:00
|
|
|
rc = -ENOMEM;
|
|
|
|
goto out_free;
|
|
|
|
}
|
2005-04-16 22:20:36 +00:00
|
|
|
|
2008-03-05 15:31:54 +00:00
|
|
|
opts->mnt_opts_flags = kcalloc(opts->num_mnt_opts, sizeof(int), GFP_ATOMIC);
|
|
|
|
if (!opts->mnt_opts_flags) {
|
2007-11-30 18:00:35 +00:00
|
|
|
rc = -ENOMEM;
|
|
|
|
goto out_free;
|
|
|
|
}
|
2005-04-16 22:20:36 +00:00
|
|
|
|
2007-11-30 18:00:35 +00:00
|
|
|
i = 0;
|
|
|
|
if (sbsec->flags & FSCONTEXT_MNT) {
|
|
|
|
rc = security_sid_to_context(sbsec->sid, &context, &len);
|
|
|
|
if (rc)
|
|
|
|
goto out_free;
|
2008-03-05 15:31:54 +00:00
|
|
|
opts->mnt_opts[i] = context;
|
|
|
|
opts->mnt_opts_flags[i++] = FSCONTEXT_MNT;
|
2007-11-30 18:00:35 +00:00
|
|
|
}
|
|
|
|
if (sbsec->flags & CONTEXT_MNT) {
|
|
|
|
rc = security_sid_to_context(sbsec->mntpoint_sid, &context, &len);
|
|
|
|
if (rc)
|
|
|
|
goto out_free;
|
2008-03-05 15:31:54 +00:00
|
|
|
opts->mnt_opts[i] = context;
|
|
|
|
opts->mnt_opts_flags[i++] = CONTEXT_MNT;
|
2007-11-30 18:00:35 +00:00
|
|
|
}
|
|
|
|
if (sbsec->flags & DEFCONTEXT_MNT) {
|
|
|
|
rc = security_sid_to_context(sbsec->def_sid, &context, &len);
|
|
|
|
if (rc)
|
|
|
|
goto out_free;
|
2008-03-05 15:31:54 +00:00
|
|
|
opts->mnt_opts[i] = context;
|
|
|
|
opts->mnt_opts_flags[i++] = DEFCONTEXT_MNT;
|
2007-11-30 18:00:35 +00:00
|
|
|
}
|
|
|
|
if (sbsec->flags & ROOTCONTEXT_MNT) {
|
|
|
|
struct inode *root = sbsec->sb->s_root->d_inode;
|
|
|
|
struct inode_security_struct *isec = root->i_security;
|
2006-07-10 11:43:55 +00:00
|
|
|
|
2007-11-30 18:00:35 +00:00
|
|
|
rc = security_sid_to_context(isec->sid, &context, &len);
|
|
|
|
if (rc)
|
|
|
|
goto out_free;
|
2008-03-05 15:31:54 +00:00
|
|
|
opts->mnt_opts[i] = context;
|
|
|
|
opts->mnt_opts_flags[i++] = ROOTCONTEXT_MNT;
|
2007-11-30 18:00:35 +00:00
|
|
|
}
|
2012-10-09 14:56:25 +00:00
|
|
|
if (sbsec->flags & SBLABEL_MNT) {
|
2009-01-16 14:22:03 +00:00
|
|
|
opts->mnt_opts[i] = NULL;
|
2012-10-09 14:56:25 +00:00
|
|
|
opts->mnt_opts_flags[i++] = SBLABEL_MNT;
|
2009-01-16 14:22:03 +00:00
|
|
|
}
|
2005-04-16 22:20:36 +00:00
|
|
|
|
2008-03-05 15:31:54 +00:00
|
|
|
BUG_ON(i != opts->num_mnt_opts);
|
2005-04-16 22:20:36 +00:00
|
|
|
|
2007-11-30 18:00:35 +00:00
|
|
|
return 0;
|
|
|
|
|
|
|
|
out_free:
|
2008-03-05 15:31:54 +00:00
|
|
|
security_free_mnt_opts(opts);
|
2007-11-30 18:00:35 +00:00
|
|
|
return rc;
|
|
|
|
}
|
2005-04-16 22:20:36 +00:00
|
|
|
|
2007-11-30 18:00:35 +00:00
|
|
|
static int bad_option(struct superblock_security_struct *sbsec, char flag,
|
|
|
|
u32 old_sid, u32 new_sid)
|
|
|
|
{
|
2009-01-16 14:22:02 +00:00
|
|
|
char mnt_flags = sbsec->flags & SE_MNTMASK;
|
|
|
|
|
2007-11-30 18:00:35 +00:00
|
|
|
/* check if the old mount command had the same options */
|
2009-01-16 14:22:02 +00:00
|
|
|
if (sbsec->flags & SE_SBINITIALIZED)
|
2007-11-30 18:00:35 +00:00
|
|
|
if (!(sbsec->flags & flag) ||
|
|
|
|
(old_sid != new_sid))
|
|
|
|
return 1;
|
|
|
|
|
|
|
|
/* check if we were passed the same options twice,
|
|
|
|
* aka someone passed context=a,context=b
|
|
|
|
*/
|
2009-01-16 14:22:02 +00:00
|
|
|
if (!(sbsec->flags & SE_SBINITIALIZED))
|
|
|
|
if (mnt_flags & flag)
|
2007-11-30 18:00:35 +00:00
|
|
|
return 1;
|
|
|
|
return 0;
|
|
|
|
}
|
2008-03-05 15:31:54 +00:00
|
|
|
|
2007-11-30 18:00:35 +00:00
|
|
|
/*
|
|
|
|
* Allow filesystems with binary mount data to explicitly set mount point
|
|
|
|
* labeling information.
|
|
|
|
*/
|
2008-03-05 15:31:54 +00:00
|
|
|
static int selinux_set_mnt_opts(struct super_block *sb,
|
2013-05-22 16:50:36 +00:00
|
|
|
struct security_mnt_opts *opts,
|
|
|
|
unsigned long kern_flags,
|
|
|
|
unsigned long *set_kern_flags)
|
2007-11-30 18:00:35 +00:00
|
|
|
{
|
2008-11-13 23:39:19 +00:00
|
|
|
const struct cred *cred = current_cred();
|
2007-11-30 18:00:35 +00:00
|
|
|
int rc = 0, i;
|
|
|
|
struct superblock_security_struct *sbsec = sb->s_security;
|
2013-12-15 19:17:45 +00:00
|
|
|
const char *name = sb->s_type->name;
|
2008-07-15 08:32:49 +00:00
|
|
|
struct inode *inode = sbsec->sb->s_root->d_inode;
|
|
|
|
struct inode_security_struct *root_isec = inode->i_security;
|
2007-11-30 18:00:35 +00:00
|
|
|
u32 fscontext_sid = 0, context_sid = 0, rootcontext_sid = 0;
|
|
|
|
u32 defcontext_sid = 0;
|
2008-03-05 15:31:54 +00:00
|
|
|
char **mount_options = opts->mnt_opts;
|
|
|
|
int *flags = opts->mnt_opts_flags;
|
|
|
|
int num_opts = opts->num_mnt_opts;
|
2007-11-30 18:00:35 +00:00
|
|
|
|
|
|
|
mutex_lock(&sbsec->lock);
|
|
|
|
|
|
|
|
if (!ss_initialized) {
|
|
|
|
if (!num_opts) {
|
|
|
|
/* Defer initialization until selinux_complete_init,
|
|
|
|
after the initial policy is loaded and the security
|
|
|
|
server is ready to handle calls. */
|
|
|
|
goto out;
|
|
|
|
}
|
|
|
|
rc = -EINVAL;
|
2008-04-17 15:52:44 +00:00
|
|
|
printk(KERN_WARNING "SELinux: Unable to set superblock options "
|
|
|
|
"before the security server is initialized\n");
|
2005-04-16 22:20:36 +00:00
|
|
|
goto out;
|
2007-11-30 18:00:35 +00:00
|
|
|
}
|
2013-05-22 16:50:36 +00:00
|
|
|
if (kern_flags && !set_kern_flags) {
|
|
|
|
/* Specifying internal flags without providing a place to
|
|
|
|
* place the results is not allowed */
|
|
|
|
rc = -EINVAL;
|
|
|
|
goto out;
|
|
|
|
}
|
2005-04-16 22:20:36 +00:00
|
|
|
|
2008-03-05 15:31:54 +00:00
|
|
|
/*
|
|
|
|
* Binary mount data FS will come through this function twice. Once
|
|
|
|
* from an explicit call and once from the generic calls from the vfs.
|
|
|
|
* Since the generic VFS calls will not contain any security mount data
|
|
|
|
* we need to skip the double mount verification.
|
|
|
|
*
|
|
|
|
* This does open a hole in which we will not notice if the first
|
|
|
|
* mount using this sb set explict options and a second mount using
|
|
|
|
* this sb does not set any security options. (The first options
|
|
|
|
* will be used for both mounts)
|
|
|
|
*/
|
2009-01-16 14:22:02 +00:00
|
|
|
if ((sbsec->flags & SE_SBINITIALIZED) && (sb->s_type->fs_flags & FS_BINARY_MOUNTDATA)
|
2008-03-05 15:31:54 +00:00
|
|
|
&& (num_opts == 0))
|
2008-05-14 15:27:45 +00:00
|
|
|
goto out;
|
2008-03-05 15:31:54 +00:00
|
|
|
|
2007-11-30 18:00:35 +00:00
|
|
|
/*
|
|
|
|
* parse the mount options, check if they are valid sids.
|
|
|
|
* also check if someone is trying to mount the same sb more
|
|
|
|
* than once with different security options.
|
|
|
|
*/
|
|
|
|
for (i = 0; i < num_opts; i++) {
|
|
|
|
u32 sid;
|
2009-01-16 14:22:03 +00:00
|
|
|
|
2012-10-09 14:56:25 +00:00
|
|
|
if (flags[i] == SBLABEL_MNT)
|
2009-01-16 14:22:03 +00:00
|
|
|
continue;
|
2007-11-30 18:00:35 +00:00
|
|
|
rc = security_context_to_sid(mount_options[i],
|
2014-03-07 11:44:19 +00:00
|
|
|
strlen(mount_options[i]), &sid, GFP_KERNEL);
|
2005-04-16 22:20:36 +00:00
|
|
|
if (rc) {
|
|
|
|
printk(KERN_WARNING "SELinux: security_context_to_sid"
|
2013-12-15 19:17:45 +00:00
|
|
|
"(%s) failed for (dev %s, type %s) errno=%d\n",
|
|
|
|
mount_options[i], sb->s_id, name, rc);
|
2007-11-30 18:00:35 +00:00
|
|
|
goto out;
|
|
|
|
}
|
|
|
|
switch (flags[i]) {
|
|
|
|
case FSCONTEXT_MNT:
|
|
|
|
fscontext_sid = sid;
|
|
|
|
|
|
|
|
if (bad_option(sbsec, FSCONTEXT_MNT, sbsec->sid,
|
|
|
|
fscontext_sid))
|
|
|
|
goto out_double_mount;
|
|
|
|
|
|
|
|
sbsec->flags |= FSCONTEXT_MNT;
|
|
|
|
break;
|
|
|
|
case CONTEXT_MNT:
|
|
|
|
context_sid = sid;
|
|
|
|
|
|
|
|
if (bad_option(sbsec, CONTEXT_MNT, sbsec->mntpoint_sid,
|
|
|
|
context_sid))
|
|
|
|
goto out_double_mount;
|
|
|
|
|
|
|
|
sbsec->flags |= CONTEXT_MNT;
|
|
|
|
break;
|
|
|
|
case ROOTCONTEXT_MNT:
|
|
|
|
rootcontext_sid = sid;
|
|
|
|
|
|
|
|
if (bad_option(sbsec, ROOTCONTEXT_MNT, root_isec->sid,
|
|
|
|
rootcontext_sid))
|
|
|
|
goto out_double_mount;
|
|
|
|
|
|
|
|
sbsec->flags |= ROOTCONTEXT_MNT;
|
|
|
|
|
|
|
|
break;
|
|
|
|
case DEFCONTEXT_MNT:
|
|
|
|
defcontext_sid = sid;
|
|
|
|
|
|
|
|
if (bad_option(sbsec, DEFCONTEXT_MNT, sbsec->def_sid,
|
|
|
|
defcontext_sid))
|
|
|
|
goto out_double_mount;
|
|
|
|
|
|
|
|
sbsec->flags |= DEFCONTEXT_MNT;
|
|
|
|
|
|
|
|
break;
|
|
|
|
default:
|
|
|
|
rc = -EINVAL;
|
|
|
|
goto out;
|
2005-04-16 22:20:36 +00:00
|
|
|
}
|
2007-11-30 18:00:35 +00:00
|
|
|
}
|
|
|
|
|
2009-01-16 14:22:02 +00:00
|
|
|
if (sbsec->flags & SE_SBINITIALIZED) {
|
2007-11-30 18:00:35 +00:00
|
|
|
/* previously mounted with options, but not on this attempt? */
|
2009-01-16 14:22:02 +00:00
|
|
|
if ((sbsec->flags & SE_MNTMASK) && !num_opts)
|
2007-11-30 18:00:35 +00:00
|
|
|
goto out_double_mount;
|
|
|
|
rc = 0;
|
|
|
|
goto out;
|
|
|
|
}
|
|
|
|
|
2008-07-15 08:32:49 +00:00
|
|
|
if (strcmp(sb->s_type->name, "proc") == 0)
|
2009-01-16 14:22:02 +00:00
|
|
|
sbsec->flags |= SE_SBPROC;
|
2007-11-30 18:00:35 +00:00
|
|
|
|
2013-05-22 16:50:37 +00:00
|
|
|
if (!sbsec->behavior) {
|
|
|
|
/*
|
|
|
|
* Determine the labeling behavior to use for this
|
|
|
|
* filesystem type.
|
|
|
|
*/
|
2013-09-18 17:52:20 +00:00
|
|
|
rc = security_fs_use(sb);
|
2013-05-22 16:50:37 +00:00
|
|
|
if (rc) {
|
|
|
|
printk(KERN_WARNING
|
|
|
|
"%s: security_fs_use(%s) returned %d\n",
|
|
|
|
__func__, sb->s_type->name, rc);
|
|
|
|
goto out;
|
|
|
|
}
|
2007-11-30 18:00:35 +00:00
|
|
|
}
|
|
|
|
/* sets the context of the superblock for the fs being mounted. */
|
|
|
|
if (fscontext_sid) {
|
2008-11-13 23:39:19 +00:00
|
|
|
rc = may_context_mount_sb_relabel(fscontext_sid, sbsec, cred);
|
2005-04-16 22:20:36 +00:00
|
|
|
if (rc)
|
2007-11-30 18:00:35 +00:00
|
|
|
goto out;
|
2005-04-16 22:20:36 +00:00
|
|
|
|
2007-11-30 18:00:35 +00:00
|
|
|
sbsec->sid = fscontext_sid;
|
2006-07-10 11:43:53 +00:00
|
|
|
}
|
|
|
|
|
|
|
|
/*
|
|
|
|
* Switch to using mount point labeling behavior.
|
|
|
|
* sets the label used on all file below the mountpoint, and will set
|
|
|
|
* the superblock context if not already set.
|
|
|
|
*/
|
2013-05-22 16:50:37 +00:00
|
|
|
if (kern_flags & SECURITY_LSM_NATIVE_LABELS && !context_sid) {
|
|
|
|
sbsec->behavior = SECURITY_FS_USE_NATIVE;
|
|
|
|
*set_kern_flags |= SECURITY_LSM_NATIVE_LABELS;
|
|
|
|
}
|
|
|
|
|
2007-11-30 18:00:35 +00:00
|
|
|
if (context_sid) {
|
|
|
|
if (!fscontext_sid) {
|
2008-11-13 23:39:19 +00:00
|
|
|
rc = may_context_mount_sb_relabel(context_sid, sbsec,
|
|
|
|
cred);
|
2006-07-14 07:24:33 +00:00
|
|
|
if (rc)
|
2007-11-30 18:00:35 +00:00
|
|
|
goto out;
|
|
|
|
sbsec->sid = context_sid;
|
2006-07-14 07:24:33 +00:00
|
|
|
} else {
|
2008-11-13 23:39:19 +00:00
|
|
|
rc = may_context_mount_inode_relabel(context_sid, sbsec,
|
|
|
|
cred);
|
2006-07-14 07:24:33 +00:00
|
|
|
if (rc)
|
2007-11-30 18:00:35 +00:00
|
|
|
goto out;
|
2006-07-14 07:24:33 +00:00
|
|
|
}
|
2007-11-30 18:00:35 +00:00
|
|
|
if (!rootcontext_sid)
|
|
|
|
rootcontext_sid = context_sid;
|
2005-04-16 22:20:36 +00:00
|
|
|
|
2007-11-30 18:00:35 +00:00
|
|
|
sbsec->mntpoint_sid = context_sid;
|
2006-07-10 11:43:53 +00:00
|
|
|
sbsec->behavior = SECURITY_FS_USE_MNTPOINT;
|
2005-04-16 22:20:36 +00:00
|
|
|
}
|
|
|
|
|
2007-11-30 18:00:35 +00:00
|
|
|
if (rootcontext_sid) {
|
2008-11-13 23:39:19 +00:00
|
|
|
rc = may_context_mount_inode_relabel(rootcontext_sid, sbsec,
|
|
|
|
cred);
|
2006-07-10 11:43:55 +00:00
|
|
|
if (rc)
|
2007-11-30 18:00:35 +00:00
|
|
|
goto out;
|
2006-07-10 11:43:55 +00:00
|
|
|
|
2007-11-30 18:00:35 +00:00
|
|
|
root_isec->sid = rootcontext_sid;
|
|
|
|
root_isec->initialized = 1;
|
2006-07-10 11:43:55 +00:00
|
|
|
}
|
|
|
|
|
2007-11-30 18:00:35 +00:00
|
|
|
if (defcontext_sid) {
|
2013-05-22 16:50:37 +00:00
|
|
|
if (sbsec->behavior != SECURITY_FS_USE_XATTR &&
|
|
|
|
sbsec->behavior != SECURITY_FS_USE_NATIVE) {
|
2007-11-30 18:00:35 +00:00
|
|
|
rc = -EINVAL;
|
|
|
|
printk(KERN_WARNING "SELinux: defcontext option is "
|
|
|
|
"invalid for this filesystem type\n");
|
|
|
|
goto out;
|
2005-04-16 22:20:36 +00:00
|
|
|
}
|
|
|
|
|
2007-11-30 18:00:35 +00:00
|
|
|
if (defcontext_sid != sbsec->def_sid) {
|
|
|
|
rc = may_context_mount_inode_relabel(defcontext_sid,
|
2008-11-13 23:39:19 +00:00
|
|
|
sbsec, cred);
|
2007-11-30 18:00:35 +00:00
|
|
|
if (rc)
|
|
|
|
goto out;
|
|
|
|
}
|
2005-04-16 22:20:36 +00:00
|
|
|
|
2007-11-30 18:00:35 +00:00
|
|
|
sbsec->def_sid = defcontext_sid;
|
2005-04-16 22:20:36 +00:00
|
|
|
}
|
|
|
|
|
2007-11-30 18:00:35 +00:00
|
|
|
rc = sb_finish_set_opts(sb);
|
2005-04-16 22:20:36 +00:00
|
|
|
out:
|
2007-11-30 18:00:35 +00:00
|
|
|
mutex_unlock(&sbsec->lock);
|
2005-04-16 22:20:36 +00:00
|
|
|
return rc;
|
2007-11-30 18:00:35 +00:00
|
|
|
out_double_mount:
|
|
|
|
rc = -EINVAL;
|
|
|
|
printk(KERN_WARNING "SELinux: mount invalid. Same superblock, different "
|
2013-12-15 19:17:45 +00:00
|
|
|
"security settings for (dev %s, type %s)\n", sb->s_id, name);
|
2007-11-30 18:00:35 +00:00
|
|
|
goto out;
|
2005-04-16 22:20:36 +00:00
|
|
|
}
|
|
|
|
|
selinux: make security_sb_clone_mnt_opts return an error on context mismatch
I had the following problem reported a while back. If you mount the
same filesystem twice using NFSv4 with different contexts, then the
second context= option is ignored. For instance:
# mount server:/export /mnt/test1
# mount server:/export /mnt/test2 -o context=system_u:object_r:tmp_t:s0
# ls -dZ /mnt/test1
drwxrwxrwt. root root system_u:object_r:nfs_t:s0 /mnt/test1
# ls -dZ /mnt/test2
drwxrwxrwt. root root system_u:object_r:nfs_t:s0 /mnt/test2
When we call into SELinux to set the context of a "cloned" superblock,
it will currently just bail out when it notices that we're reusing an
existing superblock. Since the existing superblock is already set up and
presumably in use, we can't go overwriting its context with the one from
the "original" sb. Because of this, the second context= option in this
case cannot take effect.
This patch fixes this by turning security_sb_clone_mnt_opts into an int
return operation. When it finds that the "new" superblock that it has
been handed is already set up, it checks to see whether the contexts on
the old superblock match it. If it does, then it will just return
success, otherwise it'll return -EBUSY and emit a printk to tell the
admin why the second mount failed.
Note that this patch may cause casualties. The NFSv4 code relies on
being able to walk down to an export from the pseudoroot. If you mount
filesystems that are nested within one another with different contexts,
then this patch will make those mounts fail in new and "exciting" ways.
For instance, suppose that /export is a separate filesystem on the
server:
# mount server:/ /mnt/test1
# mount salusa:/export /mnt/test2 -o context=system_u:object_r:tmp_t:s0
mount.nfs: an incorrect mount option was specified
...with the printk in the ring buffer. Because we *might* eventually
walk down to /mnt/test1/export, the mount is denied due to this patch.
The second mount needs the pseudoroot superblock, but that's already
present with the wrong context.
OTOH, if we mount these in the reverse order, then both mounts work,
because the pseudoroot superblock created when mounting /export is
discarded once that mount is done. If we then however try to walk into
that directory, the automount fails for the similar reasons:
# cd /mnt/test1/scratch/
-bash: cd: /mnt/test1/scratch: Device or resource busy
The story I've gotten from the SELinux folks that I've talked to is that
this is desirable behavior. In SELinux-land, mounting the same data
under different contexts is wrong -- there can be only one.
Cc: Steve Dickson <steved@redhat.com>
Cc: Stephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Acked-by: Eric Paris <eparis@redhat.com>
Signed-off-by: James Morris <james.l.morris@oracle.com>
2013-04-01 12:14:24 +00:00
|
|
|
static int selinux_cmp_sb_context(const struct super_block *oldsb,
|
|
|
|
const struct super_block *newsb)
|
|
|
|
{
|
|
|
|
struct superblock_security_struct *old = oldsb->s_security;
|
|
|
|
struct superblock_security_struct *new = newsb->s_security;
|
|
|
|
char oldflags = old->flags & SE_MNTMASK;
|
|
|
|
char newflags = new->flags & SE_MNTMASK;
|
|
|
|
|
|
|
|
if (oldflags != newflags)
|
|
|
|
goto mismatch;
|
|
|
|
if ((oldflags & FSCONTEXT_MNT) && old->sid != new->sid)
|
|
|
|
goto mismatch;
|
|
|
|
if ((oldflags & CONTEXT_MNT) && old->mntpoint_sid != new->mntpoint_sid)
|
|
|
|
goto mismatch;
|
|
|
|
if ((oldflags & DEFCONTEXT_MNT) && old->def_sid != new->def_sid)
|
|
|
|
goto mismatch;
|
|
|
|
if (oldflags & ROOTCONTEXT_MNT) {
|
|
|
|
struct inode_security_struct *oldroot = oldsb->s_root->d_inode->i_security;
|
|
|
|
struct inode_security_struct *newroot = newsb->s_root->d_inode->i_security;
|
|
|
|
if (oldroot->sid != newroot->sid)
|
|
|
|
goto mismatch;
|
|
|
|
}
|
|
|
|
return 0;
|
|
|
|
mismatch:
|
|
|
|
printk(KERN_WARNING "SELinux: mount invalid. Same superblock, "
|
|
|
|
"different security settings for (dev %s, "
|
|
|
|
"type %s)\n", newsb->s_id, newsb->s_type->name);
|
|
|
|
return -EBUSY;
|
|
|
|
}
|
|
|
|
|
|
|
|
static int selinux_sb_clone_mnt_opts(const struct super_block *oldsb,
|
2007-11-30 18:00:35 +00:00
|
|
|
struct super_block *newsb)
|
2005-04-16 22:20:36 +00:00
|
|
|
{
|
2007-11-30 18:00:35 +00:00
|
|
|
const struct superblock_security_struct *oldsbsec = oldsb->s_security;
|
|
|
|
struct superblock_security_struct *newsbsec = newsb->s_security;
|
2005-04-16 22:20:36 +00:00
|
|
|
|
2007-11-30 18:00:35 +00:00
|
|
|
int set_fscontext = (oldsbsec->flags & FSCONTEXT_MNT);
|
|
|
|
int set_context = (oldsbsec->flags & CONTEXT_MNT);
|
|
|
|
int set_rootcontext = (oldsbsec->flags & ROOTCONTEXT_MNT);
|
2005-04-16 22:20:36 +00:00
|
|
|
|
2008-04-21 20:24:11 +00:00
|
|
|
/*
|
|
|
|
* if the parent was able to be mounted it clearly had no special lsm
|
2010-03-23 10:36:54 +00:00
|
|
|
* mount options. thus we can safely deal with this superblock later
|
2008-04-21 20:24:11 +00:00
|
|
|
*/
|
2010-03-23 10:36:54 +00:00
|
|
|
if (!ss_initialized)
|
selinux: make security_sb_clone_mnt_opts return an error on context mismatch
I had the following problem reported a while back. If you mount the
same filesystem twice using NFSv4 with different contexts, then the
second context= option is ignored. For instance:
# mount server:/export /mnt/test1
# mount server:/export /mnt/test2 -o context=system_u:object_r:tmp_t:s0
# ls -dZ /mnt/test1
drwxrwxrwt. root root system_u:object_r:nfs_t:s0 /mnt/test1
# ls -dZ /mnt/test2
drwxrwxrwt. root root system_u:object_r:nfs_t:s0 /mnt/test2
When we call into SELinux to set the context of a "cloned" superblock,
it will currently just bail out when it notices that we're reusing an
existing superblock. Since the existing superblock is already set up and
presumably in use, we can't go overwriting its context with the one from
the "original" sb. Because of this, the second context= option in this
case cannot take effect.
This patch fixes this by turning security_sb_clone_mnt_opts into an int
return operation. When it finds that the "new" superblock that it has
been handed is already set up, it checks to see whether the contexts on
the old superblock match it. If it does, then it will just return
success, otherwise it'll return -EBUSY and emit a printk to tell the
admin why the second mount failed.
Note that this patch may cause casualties. The NFSv4 code relies on
being able to walk down to an export from the pseudoroot. If you mount
filesystems that are nested within one another with different contexts,
then this patch will make those mounts fail in new and "exciting" ways.
For instance, suppose that /export is a separate filesystem on the
server:
# mount server:/ /mnt/test1
# mount salusa:/export /mnt/test2 -o context=system_u:object_r:tmp_t:s0
mount.nfs: an incorrect mount option was specified
...with the printk in the ring buffer. Because we *might* eventually
walk down to /mnt/test1/export, the mount is denied due to this patch.
The second mount needs the pseudoroot superblock, but that's already
present with the wrong context.
OTOH, if we mount these in the reverse order, then both mounts work,
because the pseudoroot superblock created when mounting /export is
discarded once that mount is done. If we then however try to walk into
that directory, the automount fails for the similar reasons:
# cd /mnt/test1/scratch/
-bash: cd: /mnt/test1/scratch: Device or resource busy
The story I've gotten from the SELinux folks that I've talked to is that
this is desirable behavior. In SELinux-land, mounting the same data
under different contexts is wrong -- there can be only one.
Cc: Steve Dickson <steved@redhat.com>
Cc: Stephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Acked-by: Eric Paris <eparis@redhat.com>
Signed-off-by: James Morris <james.l.morris@oracle.com>
2013-04-01 12:14:24 +00:00
|
|
|
return 0;
|
2007-11-30 18:00:35 +00:00
|
|
|
|
|
|
|
/* how can we clone if the old one wasn't set up?? */
|
2009-01-16 14:22:02 +00:00
|
|
|
BUG_ON(!(oldsbsec->flags & SE_SBINITIALIZED));
|
2007-11-30 18:00:35 +00:00
|
|
|
|
selinux: make security_sb_clone_mnt_opts return an error on context mismatch
I had the following problem reported a while back. If you mount the
same filesystem twice using NFSv4 with different contexts, then the
second context= option is ignored. For instance:
# mount server:/export /mnt/test1
# mount server:/export /mnt/test2 -o context=system_u:object_r:tmp_t:s0
# ls -dZ /mnt/test1
drwxrwxrwt. root root system_u:object_r:nfs_t:s0 /mnt/test1
# ls -dZ /mnt/test2
drwxrwxrwt. root root system_u:object_r:nfs_t:s0 /mnt/test2
When we call into SELinux to set the context of a "cloned" superblock,
it will currently just bail out when it notices that we're reusing an
existing superblock. Since the existing superblock is already set up and
presumably in use, we can't go overwriting its context with the one from
the "original" sb. Because of this, the second context= option in this
case cannot take effect.
This patch fixes this by turning security_sb_clone_mnt_opts into an int
return operation. When it finds that the "new" superblock that it has
been handed is already set up, it checks to see whether the contexts on
the old superblock match it. If it does, then it will just return
success, otherwise it'll return -EBUSY and emit a printk to tell the
admin why the second mount failed.
Note that this patch may cause casualties. The NFSv4 code relies on
being able to walk down to an export from the pseudoroot. If you mount
filesystems that are nested within one another with different contexts,
then this patch will make those mounts fail in new and "exciting" ways.
For instance, suppose that /export is a separate filesystem on the
server:
# mount server:/ /mnt/test1
# mount salusa:/export /mnt/test2 -o context=system_u:object_r:tmp_t:s0
mount.nfs: an incorrect mount option was specified
...with the printk in the ring buffer. Because we *might* eventually
walk down to /mnt/test1/export, the mount is denied due to this patch.
The second mount needs the pseudoroot superblock, but that's already
present with the wrong context.
OTOH, if we mount these in the reverse order, then both mounts work,
because the pseudoroot superblock created when mounting /export is
discarded once that mount is done. If we then however try to walk into
that directory, the automount fails for the similar reasons:
# cd /mnt/test1/scratch/
-bash: cd: /mnt/test1/scratch: Device or resource busy
The story I've gotten from the SELinux folks that I've talked to is that
this is desirable behavior. In SELinux-land, mounting the same data
under different contexts is wrong -- there can be only one.
Cc: Steve Dickson <steved@redhat.com>
Cc: Stephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Acked-by: Eric Paris <eparis@redhat.com>
Signed-off-by: James Morris <james.l.morris@oracle.com>
2013-04-01 12:14:24 +00:00
|
|
|
/* if fs is reusing a sb, make sure that the contexts match */
|
2009-01-16 14:22:02 +00:00
|
|
|
if (newsbsec->flags & SE_SBINITIALIZED)
|
selinux: make security_sb_clone_mnt_opts return an error on context mismatch
I had the following problem reported a while back. If you mount the
same filesystem twice using NFSv4 with different contexts, then the
second context= option is ignored. For instance:
# mount server:/export /mnt/test1
# mount server:/export /mnt/test2 -o context=system_u:object_r:tmp_t:s0
# ls -dZ /mnt/test1
drwxrwxrwt. root root system_u:object_r:nfs_t:s0 /mnt/test1
# ls -dZ /mnt/test2
drwxrwxrwt. root root system_u:object_r:nfs_t:s0 /mnt/test2
When we call into SELinux to set the context of a "cloned" superblock,
it will currently just bail out when it notices that we're reusing an
existing superblock. Since the existing superblock is already set up and
presumably in use, we can't go overwriting its context with the one from
the "original" sb. Because of this, the second context= option in this
case cannot take effect.
This patch fixes this by turning security_sb_clone_mnt_opts into an int
return operation. When it finds that the "new" superblock that it has
been handed is already set up, it checks to see whether the contexts on
the old superblock match it. If it does, then it will just return
success, otherwise it'll return -EBUSY and emit a printk to tell the
admin why the second mount failed.
Note that this patch may cause casualties. The NFSv4 code relies on
being able to walk down to an export from the pseudoroot. If you mount
filesystems that are nested within one another with different contexts,
then this patch will make those mounts fail in new and "exciting" ways.
For instance, suppose that /export is a separate filesystem on the
server:
# mount server:/ /mnt/test1
# mount salusa:/export /mnt/test2 -o context=system_u:object_r:tmp_t:s0
mount.nfs: an incorrect mount option was specified
...with the printk in the ring buffer. Because we *might* eventually
walk down to /mnt/test1/export, the mount is denied due to this patch.
The second mount needs the pseudoroot superblock, but that's already
present with the wrong context.
OTOH, if we mount these in the reverse order, then both mounts work,
because the pseudoroot superblock created when mounting /export is
discarded once that mount is done. If we then however try to walk into
that directory, the automount fails for the similar reasons:
# cd /mnt/test1/scratch/
-bash: cd: /mnt/test1/scratch: Device or resource busy
The story I've gotten from the SELinux folks that I've talked to is that
this is desirable behavior. In SELinux-land, mounting the same data
under different contexts is wrong -- there can be only one.
Cc: Steve Dickson <steved@redhat.com>
Cc: Stephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Acked-by: Eric Paris <eparis@redhat.com>
Signed-off-by: James Morris <james.l.morris@oracle.com>
2013-04-01 12:14:24 +00:00
|
|
|
return selinux_cmp_sb_context(oldsb, newsb);
|
2008-04-09 18:08:35 +00:00
|
|
|
|
2007-11-30 18:00:35 +00:00
|
|
|
mutex_lock(&newsbsec->lock);
|
|
|
|
|
|
|
|
newsbsec->flags = oldsbsec->flags;
|
|
|
|
|
|
|
|
newsbsec->sid = oldsbsec->sid;
|
|
|
|
newsbsec->def_sid = oldsbsec->def_sid;
|
|
|
|
newsbsec->behavior = oldsbsec->behavior;
|
|
|
|
|
|
|
|
if (set_context) {
|
|
|
|
u32 sid = oldsbsec->mntpoint_sid;
|
|
|
|
|
|
|
|
if (!set_fscontext)
|
|
|
|
newsbsec->sid = sid;
|
|
|
|
if (!set_rootcontext) {
|
|
|
|
struct inode *newinode = newsb->s_root->d_inode;
|
|
|
|
struct inode_security_struct *newisec = newinode->i_security;
|
|
|
|
newisec->sid = sid;
|
|
|
|
}
|
|
|
|
newsbsec->mntpoint_sid = sid;
|
2005-04-16 22:20:36 +00:00
|
|
|
}
|
2007-11-30 18:00:35 +00:00
|
|
|
if (set_rootcontext) {
|
|
|
|
const struct inode *oldinode = oldsb->s_root->d_inode;
|
|
|
|
const struct inode_security_struct *oldisec = oldinode->i_security;
|
|
|
|
struct inode *newinode = newsb->s_root->d_inode;
|
|
|
|
struct inode_security_struct *newisec = newinode->i_security;
|
2005-04-16 22:20:36 +00:00
|
|
|
|
2007-11-30 18:00:35 +00:00
|
|
|
newisec->sid = oldisec->sid;
|
2005-04-16 22:20:36 +00:00
|
|
|
}
|
|
|
|
|
2007-11-30 18:00:35 +00:00
|
|
|
sb_finish_set_opts(newsb);
|
|
|
|
mutex_unlock(&newsbsec->lock);
|
selinux: make security_sb_clone_mnt_opts return an error on context mismatch
I had the following problem reported a while back. If you mount the
same filesystem twice using NFSv4 with different contexts, then the
second context= option is ignored. For instance:
# mount server:/export /mnt/test1
# mount server:/export /mnt/test2 -o context=system_u:object_r:tmp_t:s0
# ls -dZ /mnt/test1
drwxrwxrwt. root root system_u:object_r:nfs_t:s0 /mnt/test1
# ls -dZ /mnt/test2
drwxrwxrwt. root root system_u:object_r:nfs_t:s0 /mnt/test2
When we call into SELinux to set the context of a "cloned" superblock,
it will currently just bail out when it notices that we're reusing an
existing superblock. Since the existing superblock is already set up and
presumably in use, we can't go overwriting its context with the one from
the "original" sb. Because of this, the second context= option in this
case cannot take effect.
This patch fixes this by turning security_sb_clone_mnt_opts into an int
return operation. When it finds that the "new" superblock that it has
been handed is already set up, it checks to see whether the contexts on
the old superblock match it. If it does, then it will just return
success, otherwise it'll return -EBUSY and emit a printk to tell the
admin why the second mount failed.
Note that this patch may cause casualties. The NFSv4 code relies on
being able to walk down to an export from the pseudoroot. If you mount
filesystems that are nested within one another with different contexts,
then this patch will make those mounts fail in new and "exciting" ways.
For instance, suppose that /export is a separate filesystem on the
server:
# mount server:/ /mnt/test1
# mount salusa:/export /mnt/test2 -o context=system_u:object_r:tmp_t:s0
mount.nfs: an incorrect mount option was specified
...with the printk in the ring buffer. Because we *might* eventually
walk down to /mnt/test1/export, the mount is denied due to this patch.
The second mount needs the pseudoroot superblock, but that's already
present with the wrong context.
OTOH, if we mount these in the reverse order, then both mounts work,
because the pseudoroot superblock created when mounting /export is
discarded once that mount is done. If we then however try to walk into
that directory, the automount fails for the similar reasons:
# cd /mnt/test1/scratch/
-bash: cd: /mnt/test1/scratch: Device or resource busy
The story I've gotten from the SELinux folks that I've talked to is that
this is desirable behavior. In SELinux-land, mounting the same data
under different contexts is wrong -- there can be only one.
Cc: Steve Dickson <steved@redhat.com>
Cc: Stephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Acked-by: Eric Paris <eparis@redhat.com>
Signed-off-by: James Morris <james.l.morris@oracle.com>
2013-04-01 12:14:24 +00:00
|
|
|
return 0;
|
2007-11-30 18:00:35 +00:00
|
|
|
}
|
|
|
|
|
2008-03-17 20:29:23 +00:00
|
|
|
static int selinux_parse_opts_str(char *options,
|
|
|
|
struct security_mnt_opts *opts)
|
2007-11-30 18:00:35 +00:00
|
|
|
{
|
2008-03-05 15:31:54 +00:00
|
|
|
char *p;
|
2007-11-30 18:00:35 +00:00
|
|
|
char *context = NULL, *defcontext = NULL;
|
|
|
|
char *fscontext = NULL, *rootcontext = NULL;
|
2008-03-05 15:31:54 +00:00
|
|
|
int rc, num_mnt_opts = 0;
|
2005-04-16 22:20:36 +00:00
|
|
|
|
2008-03-05 15:31:54 +00:00
|
|
|
opts->num_mnt_opts = 0;
|
2005-04-16 22:20:36 +00:00
|
|
|
|
2007-11-30 18:00:35 +00:00
|
|
|
/* Standard string-based options. */
|
|
|
|
while ((p = strsep(&options, "|")) != NULL) {
|
|
|
|
int token;
|
|
|
|
substring_t args[MAX_OPT_ARGS];
|
2005-04-16 22:20:36 +00:00
|
|
|
|
2007-11-30 18:00:35 +00:00
|
|
|
if (!*p)
|
|
|
|
continue;
|
2005-04-16 22:20:36 +00:00
|
|
|
|
2007-11-30 18:00:35 +00:00
|
|
|
token = match_token(p, tokens, args);
|
2005-04-16 22:20:36 +00:00
|
|
|
|
2007-11-30 18:00:35 +00:00
|
|
|
switch (token) {
|
|
|
|
case Opt_context:
|
|
|
|
if (context || defcontext) {
|
|
|
|
rc = -EINVAL;
|
|
|
|
printk(KERN_WARNING SEL_MOUNT_FAIL_MSG);
|
|
|
|
goto out_err;
|
|
|
|
}
|
|
|
|
context = match_strdup(&args[0]);
|
|
|
|
if (!context) {
|
|
|
|
rc = -ENOMEM;
|
|
|
|
goto out_err;
|
|
|
|
}
|
|
|
|
break;
|
|
|
|
|
|
|
|
case Opt_fscontext:
|
|
|
|
if (fscontext) {
|
|
|
|
rc = -EINVAL;
|
|
|
|
printk(KERN_WARNING SEL_MOUNT_FAIL_MSG);
|
|
|
|
goto out_err;
|
|
|
|
}
|
|
|
|
fscontext = match_strdup(&args[0]);
|
|
|
|
if (!fscontext) {
|
|
|
|
rc = -ENOMEM;
|
|
|
|
goto out_err;
|
|
|
|
}
|
|
|
|
break;
|
|
|
|
|
|
|
|
case Opt_rootcontext:
|
|
|
|
if (rootcontext) {
|
|
|
|
rc = -EINVAL;
|
|
|
|
printk(KERN_WARNING SEL_MOUNT_FAIL_MSG);
|
|
|
|
goto out_err;
|
|
|
|
}
|
|
|
|
rootcontext = match_strdup(&args[0]);
|
|
|
|
if (!rootcontext) {
|
|
|
|
rc = -ENOMEM;
|
|
|
|
goto out_err;
|
|
|
|
}
|
|
|
|
break;
|
|
|
|
|
|
|
|
case Opt_defcontext:
|
|
|
|
if (context || defcontext) {
|
|
|
|
rc = -EINVAL;
|
|
|
|
printk(KERN_WARNING SEL_MOUNT_FAIL_MSG);
|
|
|
|
goto out_err;
|
|
|
|
}
|
|
|
|
defcontext = match_strdup(&args[0]);
|
|
|
|
if (!defcontext) {
|
|
|
|
rc = -ENOMEM;
|
|
|
|
goto out_err;
|
|
|
|
}
|
|
|
|
break;
|
2009-01-16 14:22:03 +00:00
|
|
|
case Opt_labelsupport:
|
|
|
|
break;
|
2007-11-30 18:00:35 +00:00
|
|
|
default:
|
|
|
|
rc = -EINVAL;
|
|
|
|
printk(KERN_WARNING "SELinux: unknown mount option\n");
|
|
|
|
goto out_err;
|
2005-04-16 22:20:36 +00:00
|
|
|
|
|
|
|
}
|
|
|
|
}
|
2007-11-30 18:00:35 +00:00
|
|
|
|
2008-03-05 15:31:54 +00:00
|
|
|
rc = -ENOMEM;
|
|
|
|
opts->mnt_opts = kcalloc(NUM_SEL_MNT_OPTS, sizeof(char *), GFP_ATOMIC);
|
|
|
|
if (!opts->mnt_opts)
|
|
|
|
goto out_err;
|
|
|
|
|
|
|
|
opts->mnt_opts_flags = kcalloc(NUM_SEL_MNT_OPTS, sizeof(int), GFP_ATOMIC);
|
|
|
|
if (!opts->mnt_opts_flags) {
|
|
|
|
kfree(opts->mnt_opts);
|
|
|
|
goto out_err;
|
|
|
|
}
|
|
|
|
|
2007-11-30 18:00:35 +00:00
|
|
|
if (fscontext) {
|
2008-03-05 15:31:54 +00:00
|
|
|
opts->mnt_opts[num_mnt_opts] = fscontext;
|
|
|
|
opts->mnt_opts_flags[num_mnt_opts++] = FSCONTEXT_MNT;
|
2007-11-30 18:00:35 +00:00
|
|
|
}
|
|
|
|
if (context) {
|
2008-03-05 15:31:54 +00:00
|
|
|
opts->mnt_opts[num_mnt_opts] = context;
|
|
|
|
opts->mnt_opts_flags[num_mnt_opts++] = CONTEXT_MNT;
|
2007-11-30 18:00:35 +00:00
|
|
|
}
|
|
|
|
if (rootcontext) {
|
2008-03-05 15:31:54 +00:00
|
|
|
opts->mnt_opts[num_mnt_opts] = rootcontext;
|
|
|
|
opts->mnt_opts_flags[num_mnt_opts++] = ROOTCONTEXT_MNT;
|
2007-11-30 18:00:35 +00:00
|
|
|
}
|
|
|
|
if (defcontext) {
|
2008-03-05 15:31:54 +00:00
|
|
|
opts->mnt_opts[num_mnt_opts] = defcontext;
|
|
|
|
opts->mnt_opts_flags[num_mnt_opts++] = DEFCONTEXT_MNT;
|
2007-11-30 18:00:35 +00:00
|
|
|
}
|
|
|
|
|
2008-03-05 15:31:54 +00:00
|
|
|
opts->num_mnt_opts = num_mnt_opts;
|
|
|
|
return 0;
|
|
|
|
|
2007-11-30 18:00:35 +00:00
|
|
|
out_err:
|
|
|
|
kfree(context);
|
|
|
|
kfree(defcontext);
|
|
|
|
kfree(fscontext);
|
|
|
|
kfree(rootcontext);
|
2005-04-16 22:20:36 +00:00
|
|
|
return rc;
|
|
|
|
}
|
2008-03-05 15:31:54 +00:00
|
|
|
/*
|
|
|
|
* string mount options parsing and call set the sbsec
|
|
|
|
*/
|
|
|
|
static int superblock_doinit(struct super_block *sb, void *data)
|
|
|
|
{
|
|
|
|
int rc = 0;
|
|
|
|
char *options = data;
|
|
|
|
struct security_mnt_opts opts;
|
|
|
|
|
|
|
|
security_init_mnt_opts(&opts);
|
|
|
|
|
|
|
|
if (!data)
|
|
|
|
goto out;
|
|
|
|
|
|
|
|
BUG_ON(sb->s_type->fs_flags & FS_BINARY_MOUNTDATA);
|
|
|
|
|
|
|
|
rc = selinux_parse_opts_str(options, &opts);
|
|
|
|
if (rc)
|
|
|
|
goto out_err;
|
|
|
|
|
|
|
|
out:
|
2013-05-22 16:50:36 +00:00
|
|
|
rc = selinux_set_mnt_opts(sb, &opts, 0, NULL);
|
2008-03-05 15:31:54 +00:00
|
|
|
|
|
|
|
out_err:
|
|
|
|
security_free_mnt_opts(&opts);
|
|
|
|
return rc;
|
|
|
|
}
|
2005-04-16 22:20:36 +00:00
|
|
|
|
2008-07-22 17:21:23 +00:00
|
|
|
static void selinux_write_opts(struct seq_file *m,
|
|
|
|
struct security_mnt_opts *opts)
|
2008-07-03 23:47:13 +00:00
|
|
|
{
|
|
|
|
int i;
|
|
|
|
char *prefix;
|
|
|
|
|
|
|
|
for (i = 0; i < opts->num_mnt_opts; i++) {
|
2009-01-16 14:22:03 +00:00
|
|
|
char *has_comma;
|
|
|
|
|
|
|
|
if (opts->mnt_opts[i])
|
|
|
|
has_comma = strchr(opts->mnt_opts[i], ',');
|
|
|
|
else
|
|
|
|
has_comma = NULL;
|
2008-07-03 23:47:13 +00:00
|
|
|
|
|
|
|
switch (opts->mnt_opts_flags[i]) {
|
|
|
|
case CONTEXT_MNT:
|
|
|
|
prefix = CONTEXT_STR;
|
|
|
|
break;
|
|
|
|
case FSCONTEXT_MNT:
|
|
|
|
prefix = FSCONTEXT_STR;
|
|
|
|
break;
|
|
|
|
case ROOTCONTEXT_MNT:
|
|
|
|
prefix = ROOTCONTEXT_STR;
|
|
|
|
break;
|
|
|
|
case DEFCONTEXT_MNT:
|
|
|
|
prefix = DEFCONTEXT_STR;
|
|
|
|
break;
|
2012-10-09 14:56:25 +00:00
|
|
|
case SBLABEL_MNT:
|
2009-01-16 14:22:03 +00:00
|
|
|
seq_putc(m, ',');
|
|
|
|
seq_puts(m, LABELSUPP_STR);
|
|
|
|
continue;
|
2008-07-03 23:47:13 +00:00
|
|
|
default:
|
|
|
|
BUG();
|
2011-04-20 14:21:28 +00:00
|
|
|
return;
|
2008-07-03 23:47:13 +00:00
|
|
|
};
|
|
|
|
/* we need a comma before each option */
|
|
|
|
seq_putc(m, ',');
|
|
|
|
seq_puts(m, prefix);
|
|
|
|
if (has_comma)
|
|
|
|
seq_putc(m, '\"');
|
|
|
|
seq_puts(m, opts->mnt_opts[i]);
|
|
|
|
if (has_comma)
|
|
|
|
seq_putc(m, '\"');
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
|
|
|
static int selinux_sb_show_options(struct seq_file *m, struct super_block *sb)
|
|
|
|
{
|
|
|
|
struct security_mnt_opts opts;
|
|
|
|
int rc;
|
|
|
|
|
|
|
|
rc = selinux_get_mnt_opts(sb, &opts);
|
2008-07-29 21:07:26 +00:00
|
|
|
if (rc) {
|
|
|
|
/* before policy load we may get EINVAL, don't show anything */
|
|
|
|
if (rc == -EINVAL)
|
|
|
|
rc = 0;
|
2008-07-03 23:47:13 +00:00
|
|
|
return rc;
|
2008-07-29 21:07:26 +00:00
|
|
|
}
|
2008-07-03 23:47:13 +00:00
|
|
|
|
|
|
|
selinux_write_opts(m, &opts);
|
|
|
|
|
|
|
|
security_free_mnt_opts(&opts);
|
|
|
|
|
|
|
|
return rc;
|
|
|
|
}
|
|
|
|
|
2005-04-16 22:20:36 +00:00
|
|
|
static inline u16 inode_mode_to_security_class(umode_t mode)
|
|
|
|
{
|
|
|
|
switch (mode & S_IFMT) {
|
|
|
|
case S_IFSOCK:
|
|
|
|
return SECCLASS_SOCK_FILE;
|
|
|
|
case S_IFLNK:
|
|
|
|
return SECCLASS_LNK_FILE;
|
|
|
|
case S_IFREG:
|
|
|
|
return SECCLASS_FILE;
|
|
|
|
case S_IFBLK:
|
|
|
|
return SECCLASS_BLK_FILE;
|
|
|
|
case S_IFDIR:
|
|
|
|
return SECCLASS_DIR;
|
|
|
|
case S_IFCHR:
|
|
|
|
return SECCLASS_CHR_FILE;
|
|
|
|
case S_IFIFO:
|
|
|
|
return SECCLASS_FIFO_FILE;
|
|
|
|
|
|
|
|
}
|
|
|
|
|
|
|
|
return SECCLASS_FILE;
|
|
|
|
}
|
|
|
|
|
[PATCH] SELinux - fix SCTP socket bug and general IP protocol handling
The following patch updates the way SELinux classifies and handles IP
based protocols.
Currently, IP sockets are classified by SELinux as being either TCP, UDP
or 'Raw', the latter being a default for IP socket that is not TCP or UDP.
The classification code is out of date and uses only the socket type
parameter to socket(2) to determine the class of IP socket. So, any
socket created with SOCK_STREAM will be classified by SELinux as TCP, and
SOCK_DGRAM as UDP. Also, other socket types such as SOCK_SEQPACKET and
SOCK_DCCP are currently ignored by SELinux, which classifies them as
generic sockets, which means they don't even get basic IP level checking.
This patch changes the SELinux IP socket classification logic, so that
only an IPPROTO_IP protocol value passed to socket(2) classify the socket
as TCP or UDP. The patch also drops the check for SOCK_RAW and converts
it into a default, so that socket types like SOCK_DCCP and SOCK_SEQPACKET
are classified as SECCLASS_RAWIP_SOCKET (instead of generic sockets).
Note that protocol-specific support for SCTP, DCCP etc. is not addressed
here, we're just getting these protocols checked at the IP layer.
This fixes a reported problem where SCTP sockets were being recognized as
generic SELinux sockets yet still being passed in one case to an IP level
check, which then fails for generic sockets.
It will also fix bugs where any SOCK_STREAM socket is classified as TCP or
any SOCK_DGRAM socket is classified as UDP.
This patch also unifies the way IP sockets classes are determined in
selinux_socket_bind(), so we use the already calculated value instead of
trying to recalculate it.
Signed-off-by: James Morris <jmorris@namei.org>
Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-09-30 18:24:34 +00:00
|
|
|
static inline int default_protocol_stream(int protocol)
|
|
|
|
{
|
|
|
|
return (protocol == IPPROTO_IP || protocol == IPPROTO_TCP);
|
|
|
|
}
|
|
|
|
|
|
|
|
static inline int default_protocol_dgram(int protocol)
|
|
|
|
{
|
|
|
|
return (protocol == IPPROTO_IP || protocol == IPPROTO_UDP);
|
|
|
|
}
|
|
|
|
|
2005-04-16 22:20:36 +00:00
|
|
|
static inline u16 socket_type_to_security_class(int family, int type, int protocol)
|
|
|
|
{
|
|
|
|
switch (family) {
|
|
|
|
case PF_UNIX:
|
|
|
|
switch (type) {
|
|
|
|
case SOCK_STREAM:
|
|
|
|
case SOCK_SEQPACKET:
|
|
|
|
return SECCLASS_UNIX_STREAM_SOCKET;
|
|
|
|
case SOCK_DGRAM:
|
|
|
|
return SECCLASS_UNIX_DGRAM_SOCKET;
|
|
|
|
}
|
|
|
|
break;
|
|
|
|
case PF_INET:
|
|
|
|
case PF_INET6:
|
|
|
|
switch (type) {
|
|
|
|
case SOCK_STREAM:
|
[PATCH] SELinux - fix SCTP socket bug and general IP protocol handling
The following patch updates the way SELinux classifies and handles IP
based protocols.
Currently, IP sockets are classified by SELinux as being either TCP, UDP
or 'Raw', the latter being a default for IP socket that is not TCP or UDP.
The classification code is out of date and uses only the socket type
parameter to socket(2) to determine the class of IP socket. So, any
socket created with SOCK_STREAM will be classified by SELinux as TCP, and
SOCK_DGRAM as UDP. Also, other socket types such as SOCK_SEQPACKET and
SOCK_DCCP are currently ignored by SELinux, which classifies them as
generic sockets, which means they don't even get basic IP level checking.
This patch changes the SELinux IP socket classification logic, so that
only an IPPROTO_IP protocol value passed to socket(2) classify the socket
as TCP or UDP. The patch also drops the check for SOCK_RAW and converts
it into a default, so that socket types like SOCK_DCCP and SOCK_SEQPACKET
are classified as SECCLASS_RAWIP_SOCKET (instead of generic sockets).
Note that protocol-specific support for SCTP, DCCP etc. is not addressed
here, we're just getting these protocols checked at the IP layer.
This fixes a reported problem where SCTP sockets were being recognized as
generic SELinux sockets yet still being passed in one case to an IP level
check, which then fails for generic sockets.
It will also fix bugs where any SOCK_STREAM socket is classified as TCP or
any SOCK_DGRAM socket is classified as UDP.
This patch also unifies the way IP sockets classes are determined in
selinux_socket_bind(), so we use the already calculated value instead of
trying to recalculate it.
Signed-off-by: James Morris <jmorris@namei.org>
Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-09-30 18:24:34 +00:00
|
|
|
if (default_protocol_stream(protocol))
|
|
|
|
return SECCLASS_TCP_SOCKET;
|
|
|
|
else
|
|
|
|
return SECCLASS_RAWIP_SOCKET;
|
2005-04-16 22:20:36 +00:00
|
|
|
case SOCK_DGRAM:
|
[PATCH] SELinux - fix SCTP socket bug and general IP protocol handling
The following patch updates the way SELinux classifies and handles IP
based protocols.
Currently, IP sockets are classified by SELinux as being either TCP, UDP
or 'Raw', the latter being a default for IP socket that is not TCP or UDP.
The classification code is out of date and uses only the socket type
parameter to socket(2) to determine the class of IP socket. So, any
socket created with SOCK_STREAM will be classified by SELinux as TCP, and
SOCK_DGRAM as UDP. Also, other socket types such as SOCK_SEQPACKET and
SOCK_DCCP are currently ignored by SELinux, which classifies them as
generic sockets, which means they don't even get basic IP level checking.
This patch changes the SELinux IP socket classification logic, so that
only an IPPROTO_IP protocol value passed to socket(2) classify the socket
as TCP or UDP. The patch also drops the check for SOCK_RAW and converts
it into a default, so that socket types like SOCK_DCCP and SOCK_SEQPACKET
are classified as SECCLASS_RAWIP_SOCKET (instead of generic sockets).
Note that protocol-specific support for SCTP, DCCP etc. is not addressed
here, we're just getting these protocols checked at the IP layer.
This fixes a reported problem where SCTP sockets were being recognized as
generic SELinux sockets yet still being passed in one case to an IP level
check, which then fails for generic sockets.
It will also fix bugs where any SOCK_STREAM socket is classified as TCP or
any SOCK_DGRAM socket is classified as UDP.
This patch also unifies the way IP sockets classes are determined in
selinux_socket_bind(), so we use the already calculated value instead of
trying to recalculate it.
Signed-off-by: James Morris <jmorris@namei.org>
Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-09-30 18:24:34 +00:00
|
|
|
if (default_protocol_dgram(protocol))
|
|
|
|
return SECCLASS_UDP_SOCKET;
|
|
|
|
else
|
|
|
|
return SECCLASS_RAWIP_SOCKET;
|
2006-11-14 00:09:01 +00:00
|
|
|
case SOCK_DCCP:
|
|
|
|
return SECCLASS_DCCP_SOCKET;
|
[PATCH] SELinux - fix SCTP socket bug and general IP protocol handling
The following patch updates the way SELinux classifies and handles IP
based protocols.
Currently, IP sockets are classified by SELinux as being either TCP, UDP
or 'Raw', the latter being a default for IP socket that is not TCP or UDP.
The classification code is out of date and uses only the socket type
parameter to socket(2) to determine the class of IP socket. So, any
socket created with SOCK_STREAM will be classified by SELinux as TCP, and
SOCK_DGRAM as UDP. Also, other socket types such as SOCK_SEQPACKET and
SOCK_DCCP are currently ignored by SELinux, which classifies them as
generic sockets, which means they don't even get basic IP level checking.
This patch changes the SELinux IP socket classification logic, so that
only an IPPROTO_IP protocol value passed to socket(2) classify the socket
as TCP or UDP. The patch also drops the check for SOCK_RAW and converts
it into a default, so that socket types like SOCK_DCCP and SOCK_SEQPACKET
are classified as SECCLASS_RAWIP_SOCKET (instead of generic sockets).
Note that protocol-specific support for SCTP, DCCP etc. is not addressed
here, we're just getting these protocols checked at the IP layer.
This fixes a reported problem where SCTP sockets were being recognized as
generic SELinux sockets yet still being passed in one case to an IP level
check, which then fails for generic sockets.
It will also fix bugs where any SOCK_STREAM socket is classified as TCP or
any SOCK_DGRAM socket is classified as UDP.
This patch also unifies the way IP sockets classes are determined in
selinux_socket_bind(), so we use the already calculated value instead of
trying to recalculate it.
Signed-off-by: James Morris <jmorris@namei.org>
Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-09-30 18:24:34 +00:00
|
|
|
default:
|
2005-04-16 22:20:36 +00:00
|
|
|
return SECCLASS_RAWIP_SOCKET;
|
|
|
|
}
|
|
|
|
break;
|
|
|
|
case PF_NETLINK:
|
|
|
|
switch (protocol) {
|
|
|
|
case NETLINK_ROUTE:
|
|
|
|
return SECCLASS_NETLINK_ROUTE_SOCKET;
|
|
|
|
case NETLINK_FIREWALL:
|
|
|
|
return SECCLASS_NETLINK_FIREWALL_SOCKET;
|
2011-12-06 07:56:43 +00:00
|
|
|
case NETLINK_SOCK_DIAG:
|
2005-04-16 22:20:36 +00:00
|
|
|
return SECCLASS_NETLINK_TCPDIAG_SOCKET;
|
|
|
|
case NETLINK_NFLOG:
|
|
|
|
return SECCLASS_NETLINK_NFLOG_SOCKET;
|
|
|
|
case NETLINK_XFRM:
|
|
|
|
return SECCLASS_NETLINK_XFRM_SOCKET;
|
|
|
|
case NETLINK_SELINUX:
|
|
|
|
return SECCLASS_NETLINK_SELINUX_SOCKET;
|
|
|
|
case NETLINK_AUDIT:
|
|
|
|
return SECCLASS_NETLINK_AUDIT_SOCKET;
|
|
|
|
case NETLINK_IP6_FW:
|
|
|
|
return SECCLASS_NETLINK_IP6FW_SOCKET;
|
|
|
|
case NETLINK_DNRTMSG:
|
|
|
|
return SECCLASS_NETLINK_DNRT_SOCKET;
|
2005-04-16 22:24:13 +00:00
|
|
|
case NETLINK_KOBJECT_UEVENT:
|
|
|
|
return SECCLASS_NETLINK_KOBJECT_UEVENT_SOCKET;
|
2005-04-16 22:20:36 +00:00
|
|
|
default:
|
|
|
|
return SECCLASS_NETLINK_SOCKET;
|
|
|
|
}
|
|
|
|
case PF_PACKET:
|
|
|
|
return SECCLASS_PACKET_SOCKET;
|
|
|
|
case PF_KEY:
|
|
|
|
return SECCLASS_KEY_SOCKET;
|
2006-06-09 07:25:03 +00:00
|
|
|
case PF_APPLETALK:
|
|
|
|
return SECCLASS_APPLETALK_SOCKET;
|
2005-04-16 22:20:36 +00:00
|
|
|
}
|
|
|
|
|
|
|
|
return SECCLASS_SOCKET;
|
|
|
|
}
|
|
|
|
|
|
|
|
#ifdef CONFIG_PROC_FS
|
2011-02-01 16:42:22 +00:00
|
|
|
static int selinux_proc_get_sid(struct dentry *dentry,
|
2005-04-16 22:20:36 +00:00
|
|
|
u16 tclass,
|
|
|
|
u32 *sid)
|
|
|
|
{
|
2011-02-01 16:42:22 +00:00
|
|
|
int rc;
|
|
|
|
char *buffer, *path;
|
2005-04-16 22:20:36 +00:00
|
|
|
|
2008-04-17 17:17:49 +00:00
|
|
|
buffer = (char *)__get_free_page(GFP_KERNEL);
|
2005-04-16 22:20:36 +00:00
|
|
|
if (!buffer)
|
|
|
|
return -ENOMEM;
|
|
|
|
|
2011-02-01 16:42:22 +00:00
|
|
|
path = dentry_path_raw(dentry, buffer, PAGE_SIZE);
|
|
|
|
if (IS_ERR(path))
|
|
|
|
rc = PTR_ERR(path);
|
|
|
|
else {
|
|
|
|
/* each process gets a /proc/PID/ entry. Strip off the
|
|
|
|
* PID part to get a valid selinux labeling.
|
|
|
|
* e.g. /proc/1/net/rpc/nfs -> /net/rpc/nfs */
|
|
|
|
while (path[1] >= '0' && path[1] <= '9') {
|
|
|
|
path[1] = '/';
|
|
|
|
path++;
|
|
|
|
}
|
|
|
|
rc = security_genfs_sid("proc", path, tclass, sid);
|
2005-04-16 22:20:36 +00:00
|
|
|
}
|
|
|
|
free_page((unsigned long)buffer);
|
|
|
|
return rc;
|
|
|
|
}
|
|
|
|
#else
|
2011-02-01 16:42:22 +00:00
|
|
|
static int selinux_proc_get_sid(struct dentry *dentry,
|
2005-04-16 22:20:36 +00:00
|
|
|
u16 tclass,
|
|
|
|
u32 *sid)
|
|
|
|
{
|
|
|
|
return -EINVAL;
|
|
|
|
}
|
|
|
|
#endif
|
|
|
|
|
|
|
|
/* The inode's security attributes must be initialized before first use. */
|
|
|
|
static int inode_doinit_with_dentry(struct inode *inode, struct dentry *opt_dentry)
|
|
|
|
{
|
|
|
|
struct superblock_security_struct *sbsec = NULL;
|
|
|
|
struct inode_security_struct *isec = inode->i_security;
|
|
|
|
u32 sid;
|
|
|
|
struct dentry *dentry;
|
|
|
|
#define INITCONTEXTLEN 255
|
|
|
|
char *context = NULL;
|
|
|
|
unsigned len = 0;
|
|
|
|
int rc = 0;
|
|
|
|
|
|
|
|
if (isec->initialized)
|
|
|
|
goto out;
|
|
|
|
|
2006-09-26 06:32:01 +00:00
|
|
|
mutex_lock(&isec->lock);
|
2005-04-16 22:20:36 +00:00
|
|
|
if (isec->initialized)
|
2006-09-26 06:32:01 +00:00
|
|
|
goto out_unlock;
|
2005-04-16 22:20:36 +00:00
|
|
|
|
|
|
|
sbsec = inode->i_sb->s_security;
|
2009-01-16 14:22:02 +00:00
|
|
|
if (!(sbsec->flags & SE_SBINITIALIZED)) {
|
2005-04-16 22:20:36 +00:00
|
|
|
/* Defer initialization until selinux_complete_init,
|
|
|
|
after the initial policy is loaded and the security
|
|
|
|
server is ready to handle calls. */
|
|
|
|
spin_lock(&sbsec->isec_lock);
|
|
|
|
if (list_empty(&isec->list))
|
|
|
|
list_add(&isec->list, &sbsec->isec_head);
|
|
|
|
spin_unlock(&sbsec->isec_lock);
|
2006-09-26 06:32:01 +00:00
|
|
|
goto out_unlock;
|
2005-04-16 22:20:36 +00:00
|
|
|
}
|
|
|
|
|
|
|
|
switch (sbsec->behavior) {
|
2013-05-22 16:50:37 +00:00
|
|
|
case SECURITY_FS_USE_NATIVE:
|
|
|
|
break;
|
2005-04-16 22:20:36 +00:00
|
|
|
case SECURITY_FS_USE_XATTR:
|
|
|
|
if (!inode->i_op->getxattr) {
|
|
|
|
isec->sid = sbsec->def_sid;
|
|
|
|
break;
|
|
|
|
}
|
|
|
|
|
|
|
|
/* Need a dentry, since the xattr API requires one.
|
|
|
|
Life would be simpler if we could just pass the inode. */
|
|
|
|
if (opt_dentry) {
|
|
|
|
/* Called from d_instantiate or d_splice_alias. */
|
|
|
|
dentry = dget(opt_dentry);
|
|
|
|
} else {
|
|
|
|
/* Called from selinux_complete_init, try to find a dentry. */
|
|
|
|
dentry = d_find_alias(inode);
|
|
|
|
}
|
|
|
|
if (!dentry) {
|
2009-03-09 18:35:58 +00:00
|
|
|
/*
|
|
|
|
* this is can be hit on boot when a file is accessed
|
|
|
|
* before the policy is loaded. When we load policy we
|
|
|
|
* may find inodes that have no dentry on the
|
|
|
|
* sbsec->isec_head list. No reason to complain as these
|
|
|
|
* will get fixed up the next time we go through
|
|
|
|
* inode_doinit with a dentry, before these inodes could
|
|
|
|
* be used again by userspace.
|
|
|
|
*/
|
2006-09-26 06:32:01 +00:00
|
|
|
goto out_unlock;
|
2005-04-16 22:20:36 +00:00
|
|
|
}
|
|
|
|
|
|
|
|
len = INITCONTEXTLEN;
|
2009-02-12 19:50:05 +00:00
|
|
|
context = kmalloc(len+1, GFP_NOFS);
|
2005-04-16 22:20:36 +00:00
|
|
|
if (!context) {
|
|
|
|
rc = -ENOMEM;
|
|
|
|
dput(dentry);
|
2006-09-26 06:32:01 +00:00
|
|
|
goto out_unlock;
|
2005-04-16 22:20:36 +00:00
|
|
|
}
|
2009-02-12 19:50:05 +00:00
|
|
|
context[len] = '\0';
|
2005-04-16 22:20:36 +00:00
|
|
|
rc = inode->i_op->getxattr(dentry, XATTR_NAME_SELINUX,
|
|
|
|
context, len);
|
|
|
|
if (rc == -ERANGE) {
|
2009-08-10 12:00:13 +00:00
|
|
|
kfree(context);
|
|
|
|
|
2005-04-16 22:20:36 +00:00
|
|
|
/* Need a larger buffer. Query for the right size. */
|
|
|
|
rc = inode->i_op->getxattr(dentry, XATTR_NAME_SELINUX,
|
|
|
|
NULL, 0);
|
|
|
|
if (rc < 0) {
|
|
|
|
dput(dentry);
|
2006-09-26 06:32:01 +00:00
|
|
|
goto out_unlock;
|
2005-04-16 22:20:36 +00:00
|
|
|
}
|
|
|
|
len = rc;
|
2009-02-12 19:50:05 +00:00
|
|
|
context = kmalloc(len+1, GFP_NOFS);
|
2005-04-16 22:20:36 +00:00
|
|
|
if (!context) {
|
|
|
|
rc = -ENOMEM;
|
|
|
|
dput(dentry);
|
2006-09-26 06:32:01 +00:00
|
|
|
goto out_unlock;
|
2005-04-16 22:20:36 +00:00
|
|
|
}
|
2009-02-12 19:50:05 +00:00
|
|
|
context[len] = '\0';
|
2005-04-16 22:20:36 +00:00
|
|
|
rc = inode->i_op->getxattr(dentry,
|
|
|
|
XATTR_NAME_SELINUX,
|
|
|
|
context, len);
|
|
|
|
}
|
|
|
|
dput(dentry);
|
|
|
|
if (rc < 0) {
|
|
|
|
if (rc != -ENODATA) {
|
2008-04-17 15:52:44 +00:00
|
|
|
printk(KERN_WARNING "SELinux: %s: getxattr returned "
|
2008-03-05 23:03:59 +00:00
|
|
|
"%d for dev=%s ino=%ld\n", __func__,
|
2005-04-16 22:20:36 +00:00
|
|
|
-rc, inode->i_sb->s_id, inode->i_ino);
|
|
|
|
kfree(context);
|
2006-09-26 06:32:01 +00:00
|
|
|
goto out_unlock;
|
2005-04-16 22:20:36 +00:00
|
|
|
}
|
|
|
|
/* Map ENODATA to the default file SID */
|
|
|
|
sid = sbsec->def_sid;
|
|
|
|
rc = 0;
|
|
|
|
} else {
|
2005-07-28 08:07:37 +00:00
|
|
|
rc = security_context_to_sid_default(context, rc, &sid,
|
2008-04-04 12:46:05 +00:00
|
|
|
sbsec->def_sid,
|
|
|
|
GFP_NOFS);
|
2005-04-16 22:20:36 +00:00
|
|
|
if (rc) {
|
2009-02-12 20:01:10 +00:00
|
|
|
char *dev = inode->i_sb->s_id;
|
|
|
|
unsigned long ino = inode->i_ino;
|
|
|
|
|
|
|
|
if (rc == -EINVAL) {
|
|
|
|
if (printk_ratelimit())
|
|
|
|
printk(KERN_NOTICE "SELinux: inode=%lu on dev=%s was found to have an invalid "
|
|
|
|
"context=%s. This indicates you may need to relabel the inode or the "
|
|
|
|
"filesystem in question.\n", ino, dev, context);
|
|
|
|
} else {
|
|
|
|
printk(KERN_WARNING "SELinux: %s: context_to_sid(%s) "
|
|
|
|
"returned %d for dev=%s ino=%ld\n",
|
|
|
|
__func__, context, -rc, dev, ino);
|
|
|
|
}
|
2005-04-16 22:20:36 +00:00
|
|
|
kfree(context);
|
|
|
|
/* Leave with the unlabeled SID */
|
|
|
|
rc = 0;
|
|
|
|
break;
|
|
|
|
}
|
|
|
|
}
|
|
|
|
kfree(context);
|
|
|
|
isec->sid = sid;
|
|
|
|
break;
|
|
|
|
case SECURITY_FS_USE_TASK:
|
|
|
|
isec->sid = isec->task_sid;
|
|
|
|
break;
|
|
|
|
case SECURITY_FS_USE_TRANS:
|
|
|
|
/* Default to the fs SID. */
|
|
|
|
isec->sid = sbsec->sid;
|
|
|
|
|
|
|
|
/* Try to obtain a transition SID. */
|
|
|
|
isec->sclass = inode_mode_to_security_class(inode->i_mode);
|
SELinux: Use dentry name in new object labeling
Currently SELinux has rules which label new objects according to 3 criteria.
The label of the process creating the object, the label of the parent
directory, and the type of object (reg, dir, char, block, etc.) This patch
adds a 4th criteria, the dentry name, thus we can distinguish between
creating a file in an etc_t directory called shadow and one called motd.
There is no file globbing, regex parsing, or anything mystical. Either the
policy exactly (strcmp) matches the dentry name of the object or it doesn't.
This patch has no changes from today if policy does not implement the new
rules.
Signed-off-by: Eric Paris <eparis@redhat.com>
2011-02-01 16:05:40 +00:00
|
|
|
rc = security_transition_sid(isec->task_sid, sbsec->sid,
|
|
|
|
isec->sclass, NULL, &sid);
|
2005-04-16 22:20:36 +00:00
|
|
|
if (rc)
|
2006-09-26 06:32:01 +00:00
|
|
|
goto out_unlock;
|
2005-04-16 22:20:36 +00:00
|
|
|
isec->sid = sid;
|
|
|
|
break;
|
2006-07-10 11:43:53 +00:00
|
|
|
case SECURITY_FS_USE_MNTPOINT:
|
|
|
|
isec->sid = sbsec->mntpoint_sid;
|
|
|
|
break;
|
2005-04-16 22:20:36 +00:00
|
|
|
default:
|
2006-07-10 11:43:53 +00:00
|
|
|
/* Default to the fs superblock SID. */
|
2005-04-16 22:20:36 +00:00
|
|
|
isec->sid = sbsec->sid;
|
|
|
|
|
2009-01-16 14:22:02 +00:00
|
|
|
if ((sbsec->flags & SE_SBPROC) && !S_ISLNK(inode->i_mode)) {
|
2014-03-19 20:46:18 +00:00
|
|
|
/* We must have a dentry to determine the label on
|
|
|
|
* procfs inodes */
|
|
|
|
if (opt_dentry)
|
|
|
|
/* Called from d_instantiate or
|
|
|
|
* d_splice_alias. */
|
|
|
|
dentry = dget(opt_dentry);
|
|
|
|
else
|
|
|
|
/* Called from selinux_complete_init, try to
|
|
|
|
* find a dentry. */
|
|
|
|
dentry = d_find_alias(inode);
|
|
|
|
/*
|
|
|
|
* This can be hit on boot when a file is accessed
|
|
|
|
* before the policy is loaded. When we load policy we
|
|
|
|
* may find inodes that have no dentry on the
|
|
|
|
* sbsec->isec_head list. No reason to complain as
|
|
|
|
* these will get fixed up the next time we go through
|
|
|
|
* inode_doinit() with a dentry, before these inodes
|
|
|
|
* could be used again by userspace.
|
|
|
|
*/
|
|
|
|
if (!dentry)
|
|
|
|
goto out_unlock;
|
|
|
|
isec->sclass = inode_mode_to_security_class(inode->i_mode);
|
|
|
|
rc = selinux_proc_get_sid(dentry, isec->sclass, &sid);
|
|
|
|
dput(dentry);
|
|
|
|
if (rc)
|
|
|
|
goto out_unlock;
|
|
|
|
isec->sid = sid;
|
2005-04-16 22:20:36 +00:00
|
|
|
}
|
|
|
|
break;
|
|
|
|
}
|
|
|
|
|
|
|
|
isec->initialized = 1;
|
|
|
|
|
2006-09-26 06:32:01 +00:00
|
|
|
out_unlock:
|
|
|
|
mutex_unlock(&isec->lock);
|
2005-04-16 22:20:36 +00:00
|
|
|
out:
|
|
|
|
if (isec->sclass == SECCLASS_FILE)
|
|
|
|
isec->sclass = inode_mode_to_security_class(inode->i_mode);
|
|
|
|
return rc;
|
|
|
|
}
|
|
|
|
|
|
|
|
/* Convert a Linux signal to an access vector. */
|
|
|
|
static inline u32 signal_to_av(int sig)
|
|
|
|
{
|
|
|
|
u32 perm = 0;
|
|
|
|
|
|
|
|
switch (sig) {
|
|
|
|
case SIGCHLD:
|
|
|
|
/* Commonly granted from child to parent. */
|
|
|
|
perm = PROCESS__SIGCHLD;
|
|
|
|
break;
|
|
|
|
case SIGKILL:
|
|
|
|
/* Cannot be caught or ignored */
|
|
|
|
perm = PROCESS__SIGKILL;
|
|
|
|
break;
|
|
|
|
case SIGSTOP:
|
|
|
|
/* Cannot be caught or ignored */
|
|
|
|
perm = PROCESS__SIGSTOP;
|
|
|
|
break;
|
|
|
|
default:
|
|
|
|
/* All other signals. */
|
|
|
|
perm = PROCESS__SIGNAL;
|
|
|
|
break;
|
|
|
|
}
|
|
|
|
|
|
|
|
return perm;
|
|
|
|
}
|
|
|
|
|
CRED: Inaugurate COW credentials
Inaugurate copy-on-write credentials management. This uses RCU to manage the
credentials pointer in the task_struct with respect to accesses by other tasks.
A process may only modify its own credentials, and so does not need locking to
access or modify its own credentials.
A mutex (cred_replace_mutex) is added to the task_struct to control the effect
of PTRACE_ATTACHED on credential calculations, particularly with respect to
execve().
With this patch, the contents of an active credentials struct may not be
changed directly; rather a new set of credentials must be prepared, modified
and committed using something like the following sequence of events:
struct cred *new = prepare_creds();
int ret = blah(new);
if (ret < 0) {
abort_creds(new);
return ret;
}
return commit_creds(new);
There are some exceptions to this rule: the keyrings pointed to by the active
credentials may be instantiated - keyrings violate the COW rule as managing
COW keyrings is tricky, given that it is possible for a task to directly alter
the keys in a keyring in use by another task.
To help enforce this, various pointers to sets of credentials, such as those in
the task_struct, are declared const. The purpose of this is compile-time
discouragement of altering credentials through those pointers. Once a set of
credentials has been made public through one of these pointers, it may not be
modified, except under special circumstances:
(1) Its reference count may incremented and decremented.
(2) The keyrings to which it points may be modified, but not replaced.
The only safe way to modify anything else is to create a replacement and commit
using the functions described in Documentation/credentials.txt (which will be
added by a later patch).
This patch and the preceding patches have been tested with the LTP SELinux
testsuite.
This patch makes several logical sets of alteration:
(1) execve().
This now prepares and commits credentials in various places in the
security code rather than altering the current creds directly.
(2) Temporary credential overrides.
do_coredump() and sys_faccessat() now prepare their own credentials and
temporarily override the ones currently on the acting thread, whilst
preventing interference from other threads by holding cred_replace_mutex
on the thread being dumped.
This will be replaced in a future patch by something that hands down the
credentials directly to the functions being called, rather than altering
the task's objective credentials.
(3) LSM interface.
A number of functions have been changed, added or removed:
(*) security_capset_check(), ->capset_check()
(*) security_capset_set(), ->capset_set()
Removed in favour of security_capset().
(*) security_capset(), ->capset()
New. This is passed a pointer to the new creds, a pointer to the old
creds and the proposed capability sets. It should fill in the new
creds or return an error. All pointers, barring the pointer to the
new creds, are now const.
(*) security_bprm_apply_creds(), ->bprm_apply_creds()
Changed; now returns a value, which will cause the process to be
killed if it's an error.
(*) security_task_alloc(), ->task_alloc_security()
Removed in favour of security_prepare_creds().
(*) security_cred_free(), ->cred_free()
New. Free security data attached to cred->security.
(*) security_prepare_creds(), ->cred_prepare()
New. Duplicate any security data attached to cred->security.
(*) security_commit_creds(), ->cred_commit()
New. Apply any security effects for the upcoming installation of new
security by commit_creds().
(*) security_task_post_setuid(), ->task_post_setuid()
Removed in favour of security_task_fix_setuid().
(*) security_task_fix_setuid(), ->task_fix_setuid()
Fix up the proposed new credentials for setuid(). This is used by
cap_set_fix_setuid() to implicitly adjust capabilities in line with
setuid() changes. Changes are made to the new credentials, rather
than the task itself as in security_task_post_setuid().
(*) security_task_reparent_to_init(), ->task_reparent_to_init()
Removed. Instead the task being reparented to init is referred
directly to init's credentials.
NOTE! This results in the loss of some state: SELinux's osid no
longer records the sid of the thread that forked it.
(*) security_key_alloc(), ->key_alloc()
(*) security_key_permission(), ->key_permission()
Changed. These now take cred pointers rather than task pointers to
refer to the security context.
(4) sys_capset().
This has been simplified and uses less locking. The LSM functions it
calls have been merged.
(5) reparent_to_kthreadd().
This gives the current thread the same credentials as init by simply using
commit_thread() to point that way.
(6) __sigqueue_alloc() and switch_uid()
__sigqueue_alloc() can't stop the target task from changing its creds
beneath it, so this function gets a reference to the currently applicable
user_struct which it then passes into the sigqueue struct it returns if
successful.
switch_uid() is now called from commit_creds(), and possibly should be
folded into that. commit_creds() should take care of protecting
__sigqueue_alloc().
(7) [sg]et[ug]id() and co and [sg]et_current_groups.
The set functions now all use prepare_creds(), commit_creds() and
abort_creds() to build and check a new set of credentials before applying
it.
security_task_set[ug]id() is called inside the prepared section. This
guarantees that nothing else will affect the creds until we've finished.
The calling of set_dumpable() has been moved into commit_creds().
Much of the functionality of set_user() has been moved into
commit_creds().
The get functions all simply access the data directly.
(8) security_task_prctl() and cap_task_prctl().
security_task_prctl() has been modified to return -ENOSYS if it doesn't
want to handle a function, or otherwise return the return value directly
rather than through an argument.
Additionally, cap_task_prctl() now prepares a new set of credentials, even
if it doesn't end up using it.
(9) Keyrings.
A number of changes have been made to the keyrings code:
(a) switch_uid_keyring(), copy_keys(), exit_keys() and suid_keys() have
all been dropped and built in to the credentials functions directly.
They may want separating out again later.
(b) key_alloc() and search_process_keyrings() now take a cred pointer
rather than a task pointer to specify the security context.
(c) copy_creds() gives a new thread within the same thread group a new
thread keyring if its parent had one, otherwise it discards the thread
keyring.
(d) The authorisation key now points directly to the credentials to extend
the search into rather pointing to the task that carries them.
(e) Installing thread, process or session keyrings causes a new set of
credentials to be created, even though it's not strictly necessary for
process or session keyrings (they're shared).
(10) Usermode helper.
The usermode helper code now carries a cred struct pointer in its
subprocess_info struct instead of a new session keyring pointer. This set
of credentials is derived from init_cred and installed on the new process
after it has been cloned.
call_usermodehelper_setup() allocates the new credentials and
call_usermodehelper_freeinfo() discards them if they haven't been used. A
special cred function (prepare_usermodeinfo_creds()) is provided
specifically for call_usermodehelper_setup() to call.
call_usermodehelper_setkeys() adjusts the credentials to sport the
supplied keyring as the new session keyring.
(11) SELinux.
SELinux has a number of changes, in addition to those to support the LSM
interface changes mentioned above:
(a) selinux_setprocattr() no longer does its check for whether the
current ptracer can access processes with the new SID inside the lock
that covers getting the ptracer's SID. Whilst this lock ensures that
the check is done with the ptracer pinned, the result is only valid
until the lock is released, so there's no point doing it inside the
lock.
(12) is_single_threaded().
This function has been extracted from selinux_setprocattr() and put into
a file of its own in the lib/ directory as join_session_keyring() now
wants to use it too.
The code in SELinux just checked to see whether a task shared mm_structs
with other tasks (CLONE_VM), but that isn't good enough. We really want
to know if they're part of the same thread group (CLONE_THREAD).
(13) nfsd.
The NFS server daemon now has to use the COW credentials to set the
credentials it is going to use. It really needs to pass the credentials
down to the functions it calls, but it can't do that until other patches
in this series have been applied.
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: James Morris <jmorris@namei.org>
Signed-off-by: James Morris <jmorris@namei.org>
2008-11-13 23:39:23 +00:00
|
|
|
/*
|
|
|
|
* Check permission between a pair of credentials
|
|
|
|
* fork check, ptrace check, etc.
|
|
|
|
*/
|
|
|
|
static int cred_has_perm(const struct cred *actor,
|
|
|
|
const struct cred *target,
|
|
|
|
u32 perms)
|
|
|
|
{
|
|
|
|
u32 asid = cred_sid(actor), tsid = cred_sid(target);
|
|
|
|
|
|
|
|
return avc_has_perm(asid, tsid, SECCLASS_PROCESS, perms, NULL);
|
|
|
|
}
|
|
|
|
|
2008-11-13 23:39:19 +00:00
|
|
|
/*
|
2008-11-13 23:39:21 +00:00
|
|
|
* Check permission between a pair of tasks, e.g. signal checks,
|
2008-11-13 23:39:19 +00:00
|
|
|
* fork check, ptrace check, etc.
|
|
|
|
* tsk1 is the actor and tsk2 is the target
|
2008-11-13 23:39:26 +00:00
|
|
|
* - this uses the default subjective creds of tsk1
|
2008-11-13 23:39:19 +00:00
|
|
|
*/
|
|
|
|
static int task_has_perm(const struct task_struct *tsk1,
|
|
|
|
const struct task_struct *tsk2,
|
2005-04-16 22:20:36 +00:00
|
|
|
u32 perms)
|
|
|
|
{
|
2008-11-13 23:39:19 +00:00
|
|
|
const struct task_security_struct *__tsec1, *__tsec2;
|
|
|
|
u32 sid1, sid2;
|
2005-04-16 22:20:36 +00:00
|
|
|
|
2008-11-13 23:39:19 +00:00
|
|
|
rcu_read_lock();
|
|
|
|
__tsec1 = __task_cred(tsk1)->security; sid1 = __tsec1->sid;
|
|
|
|
__tsec2 = __task_cred(tsk2)->security; sid2 = __tsec2->sid;
|
|
|
|
rcu_read_unlock();
|
|
|
|
return avc_has_perm(sid1, sid2, SECCLASS_PROCESS, perms, NULL);
|
2005-04-16 22:20:36 +00:00
|
|
|
}
|
|
|
|
|
2008-11-13 23:39:26 +00:00
|
|
|
/*
|
|
|
|
* Check permission between current and another task, e.g. signal checks,
|
|
|
|
* fork check, ptrace check, etc.
|
|
|
|
* current is the actor and tsk2 is the target
|
|
|
|
* - this uses current's subjective creds
|
|
|
|
*/
|
|
|
|
static int current_has_perm(const struct task_struct *tsk,
|
|
|
|
u32 perms)
|
|
|
|
{
|
|
|
|
u32 sid, tsid;
|
|
|
|
|
|
|
|
sid = current_sid();
|
|
|
|
tsid = task_sid(tsk);
|
|
|
|
return avc_has_perm(sid, tsid, SECCLASS_PROCESS, perms, NULL);
|
|
|
|
}
|
|
|
|
|
2008-02-07 16:21:04 +00:00
|
|
|
#if CAP_LAST_CAP > 63
|
|
|
|
#error Fix SELinux to handle capabilities > 63.
|
|
|
|
#endif
|
|
|
|
|
2005-04-16 22:20:36 +00:00
|
|
|
/* Check whether a task is allowed to use a capability. */
|
2012-01-03 17:25:14 +00:00
|
|
|
static int cred_has_capability(const struct cred *cred,
|
2008-11-11 11:02:50 +00:00
|
|
|
int cap, int audit)
|
2005-04-16 22:20:36 +00:00
|
|
|
{
|
2009-07-14 16:14:09 +00:00
|
|
|
struct common_audit_data ad;
|
2008-11-11 11:02:50 +00:00
|
|
|
struct av_decision avd;
|
2008-02-07 16:21:04 +00:00
|
|
|
u16 sclass;
|
CRED: Fix regression in cap_capable() as shown up by sys_faccessat() [ver #3]
Fix a regression in cap_capable() due to:
commit 3b11a1decef07c19443d24ae926982bc8ec9f4c0
Author: David Howells <dhowells@redhat.com>
Date: Fri Nov 14 10:39:26 2008 +1100
CRED: Differentiate objective and effective subjective credentials on a task
The problem is that the above patch allows a process to have two sets of
credentials, and for the most part uses the subjective credentials when
accessing current's creds.
There is, however, one exception: cap_capable(), and thus capable(), uses the
real/objective credentials of the target task, whether or not it is the current
task.
Ordinarily this doesn't matter, since usually the two cred pointers in current
point to the same set of creds. However, sys_faccessat() makes use of this
facility to override the credentials of the calling process to make its test,
without affecting the creds as seen from other processes.
One of the things sys_faccessat() does is to make an adjustment to the
effective capabilities mask, which cap_capable(), as it stands, then ignores.
The affected capability check is in generic_permission():
if (!(mask & MAY_EXEC) || execute_ok(inode))
if (capable(CAP_DAC_OVERRIDE))
return 0;
This change passes the set of credentials to be tested down into the commoncap
and SELinux code. The security functions called by capable() and
has_capability() select the appropriate set of credentials from the process
being checked.
This can be tested by compiling the following program from the XFS testsuite:
/*
* t_access_root.c - trivial test program to show permission bug.
*
* Written by Michael Kerrisk - copyright ownership not pursued.
* Sourced from: http://linux.derkeiler.com/Mailing-Lists/Kernel/2003-10/6030.html
*/
#include <limits.h>
#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>
#include <fcntl.h>
#include <sys/stat.h>
#define UID 500
#define GID 100
#define PERM 0
#define TESTPATH "/tmp/t_access"
static void
errExit(char *msg)
{
perror(msg);
exit(EXIT_FAILURE);
} /* errExit */
static void
accessTest(char *file, int mask, char *mstr)
{
printf("access(%s, %s) returns %d\n", file, mstr, access(file, mask));
} /* accessTest */
int
main(int argc, char *argv[])
{
int fd, perm, uid, gid;
char *testpath;
char cmd[PATH_MAX + 20];
testpath = (argc > 1) ? argv[1] : TESTPATH;
perm = (argc > 2) ? strtoul(argv[2], NULL, 8) : PERM;
uid = (argc > 3) ? atoi(argv[3]) : UID;
gid = (argc > 4) ? atoi(argv[4]) : GID;
unlink(testpath);
fd = open(testpath, O_RDWR | O_CREAT, 0);
if (fd == -1) errExit("open");
if (fchown(fd, uid, gid) == -1) errExit("fchown");
if (fchmod(fd, perm) == -1) errExit("fchmod");
close(fd);
snprintf(cmd, sizeof(cmd), "ls -l %s", testpath);
system(cmd);
if (seteuid(uid) == -1) errExit("seteuid");
accessTest(testpath, 0, "0");
accessTest(testpath, R_OK, "R_OK");
accessTest(testpath, W_OK, "W_OK");
accessTest(testpath, X_OK, "X_OK");
accessTest(testpath, R_OK | W_OK, "R_OK | W_OK");
accessTest(testpath, R_OK | X_OK, "R_OK | X_OK");
accessTest(testpath, W_OK | X_OK, "W_OK | X_OK");
accessTest(testpath, R_OK | W_OK | X_OK, "R_OK | W_OK | X_OK");
exit(EXIT_SUCCESS);
} /* main */
This can be run against an Ext3 filesystem as well as against an XFS
filesystem. If successful, it will show:
[root@andromeda src]# ./t_access_root /tmp/xxx 0 4043 4043
---------- 1 dhowells dhowells 0 2008-12-31 03:00 /tmp/xxx
access(/tmp/xxx, 0) returns 0
access(/tmp/xxx, R_OK) returns 0
access(/tmp/xxx, W_OK) returns 0
access(/tmp/xxx, X_OK) returns -1
access(/tmp/xxx, R_OK | W_OK) returns 0
access(/tmp/xxx, R_OK | X_OK) returns -1
access(/tmp/xxx, W_OK | X_OK) returns -1
access(/tmp/xxx, R_OK | W_OK | X_OK) returns -1
If unsuccessful, it will show:
[root@andromeda src]# ./t_access_root /tmp/xxx 0 4043 4043
---------- 1 dhowells dhowells 0 2008-12-31 02:56 /tmp/xxx
access(/tmp/xxx, 0) returns 0
access(/tmp/xxx, R_OK) returns -1
access(/tmp/xxx, W_OK) returns -1
access(/tmp/xxx, X_OK) returns -1
access(/tmp/xxx, R_OK | W_OK) returns -1
access(/tmp/xxx, R_OK | X_OK) returns -1
access(/tmp/xxx, W_OK | X_OK) returns -1
access(/tmp/xxx, R_OK | W_OK | X_OK) returns -1
I've also tested the fix with the SELinux and syscalls LTP testsuites.
Signed-off-by: David Howells <dhowells@redhat.com>
Tested-by: J. Bruce Fields <bfields@citi.umich.edu>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Signed-off-by: James Morris <jmorris@namei.org>
2009-01-06 22:27:01 +00:00
|
|
|
u32 sid = cred_sid(cred);
|
2008-02-07 16:21:04 +00:00
|
|
|
u32 av = CAP_TO_MASK(cap);
|
2008-11-11 11:02:50 +00:00
|
|
|
int rc;
|
2005-04-16 22:20:36 +00:00
|
|
|
|
2012-04-04 19:01:43 +00:00
|
|
|
ad.type = LSM_AUDIT_DATA_CAP;
|
2005-04-16 22:20:36 +00:00
|
|
|
ad.u.cap = cap;
|
|
|
|
|
2008-02-07 16:21:04 +00:00
|
|
|
switch (CAP_TO_INDEX(cap)) {
|
|
|
|
case 0:
|
|
|
|
sclass = SECCLASS_CAPABILITY;
|
|
|
|
break;
|
|
|
|
case 1:
|
|
|
|
sclass = SECCLASS_CAPABILITY2;
|
|
|
|
break;
|
|
|
|
default:
|
|
|
|
printk(KERN_ERR
|
|
|
|
"SELinux: out of range capability %d\n", cap);
|
|
|
|
BUG();
|
2011-04-20 14:21:28 +00:00
|
|
|
return -EINVAL;
|
2008-02-07 16:21:04 +00:00
|
|
|
}
|
2008-11-11 11:02:50 +00:00
|
|
|
|
2008-11-13 23:39:19 +00:00
|
|
|
rc = avc_has_perm_noaudit(sid, sid, sclass, av, 0, &avd);
|
2011-04-25 20:26:29 +00:00
|
|
|
if (audit == SECURITY_CAP_AUDIT) {
|
2013-10-04 21:05:38 +00:00
|
|
|
int rc2 = avc_audit(sid, sid, sclass, av, &avd, rc, &ad);
|
2011-04-25 20:26:29 +00:00
|
|
|
if (rc2)
|
|
|
|
return rc2;
|
|
|
|
}
|
2008-11-11 11:02:50 +00:00
|
|
|
return rc;
|
2005-04-16 22:20:36 +00:00
|
|
|
}
|
|
|
|
|
|
|
|
/* Check whether a task is allowed to use a system operation. */
|
|
|
|
static int task_has_system(struct task_struct *tsk,
|
|
|
|
u32 perms)
|
|
|
|
{
|
2008-11-13 23:39:19 +00:00
|
|
|
u32 sid = task_sid(tsk);
|
2005-04-16 22:20:36 +00:00
|
|
|
|
2008-11-13 23:39:19 +00:00
|
|
|
return avc_has_perm(sid, SECINITSID_KERNEL,
|
2005-04-16 22:20:36 +00:00
|
|
|
SECCLASS_SYSTEM, perms, NULL);
|
|
|
|
}
|
|
|
|
|
|
|
|
/* Check whether a task has a particular permission to an inode.
|
|
|
|
The 'adp' parameter is optional and allows other audit
|
|
|
|
data to be passed (e.g. the dentry). */
|
2008-11-13 23:39:21 +00:00
|
|
|
static int inode_has_perm(const struct cred *cred,
|
2005-04-16 22:20:36 +00:00
|
|
|
struct inode *inode,
|
|
|
|
u32 perms,
|
2013-10-04 19:54:11 +00:00
|
|
|
struct common_audit_data *adp)
|
2005-04-16 22:20:36 +00:00
|
|
|
{
|
|
|
|
struct inode_security_struct *isec;
|
2008-11-13 23:39:19 +00:00
|
|
|
u32 sid;
|
2005-04-16 22:20:36 +00:00
|
|
|
|
2009-09-02 08:13:40 +00:00
|
|
|
validate_creds(cred);
|
|
|
|
|
2008-04-17 17:17:49 +00:00
|
|
|
if (unlikely(IS_PRIVATE(inode)))
|
2007-02-14 08:34:16 +00:00
|
|
|
return 0;
|
|
|
|
|
2008-11-13 23:39:21 +00:00
|
|
|
sid = cred_sid(cred);
|
2005-04-16 22:20:36 +00:00
|
|
|
isec = inode->i_security;
|
|
|
|
|
2013-10-04 19:54:11 +00:00
|
|
|
return avc_has_perm(sid, isec->sid, isec->sclass, perms, adp);
|
2005-04-16 22:20:36 +00:00
|
|
|
}
|
|
|
|
|
|
|
|
/* Same as inode_has_perm, but pass explicit audit data containing
|
|
|
|
the dentry to help the auditing code to more easily generate the
|
|
|
|
pathname if needed. */
|
2008-11-13 23:39:21 +00:00
|
|
|
static inline int dentry_has_perm(const struct cred *cred,
|
2005-04-16 22:20:36 +00:00
|
|
|
struct dentry *dentry,
|
|
|
|
u32 av)
|
|
|
|
{
|
|
|
|
struct inode *inode = dentry->d_inode;
|
2009-07-14 16:14:09 +00:00
|
|
|
struct common_audit_data ad;
|
2008-11-13 23:39:21 +00:00
|
|
|
|
2012-04-04 19:01:43 +00:00
|
|
|
ad.type = LSM_AUDIT_DATA_DENTRY;
|
2011-04-28 20:04:24 +00:00
|
|
|
ad.u.dentry = dentry;
|
2013-10-04 19:54:11 +00:00
|
|
|
return inode_has_perm(cred, inode, av, &ad);
|
2011-04-28 20:04:24 +00:00
|
|
|
}
|
|
|
|
|
|
|
|
/* Same as inode_has_perm, but pass explicit audit data containing
|
|
|
|
the path to help the auditing code to more easily generate the
|
|
|
|
pathname if needed. */
|
|
|
|
static inline int path_has_perm(const struct cred *cred,
|
|
|
|
struct path *path,
|
|
|
|
u32 av)
|
|
|
|
{
|
|
|
|
struct inode *inode = path->dentry->d_inode;
|
|
|
|
struct common_audit_data ad;
|
|
|
|
|
2012-04-04 19:01:43 +00:00
|
|
|
ad.type = LSM_AUDIT_DATA_PATH;
|
2011-04-28 20:04:24 +00:00
|
|
|
ad.u.path = *path;
|
2013-10-04 19:54:11 +00:00
|
|
|
return inode_has_perm(cred, inode, av, &ad);
|
2005-04-16 22:20:36 +00:00
|
|
|
}
|
|
|
|
|
2013-06-13 22:37:55 +00:00
|
|
|
/* Same as path_has_perm, but uses the inode from the file struct. */
|
|
|
|
static inline int file_path_has_perm(const struct cred *cred,
|
|
|
|
struct file *file,
|
|
|
|
u32 av)
|
|
|
|
{
|
|
|
|
struct common_audit_data ad;
|
|
|
|
|
|
|
|
ad.type = LSM_AUDIT_DATA_PATH;
|
|
|
|
ad.u.path = file->f_path;
|
2013-10-04 19:54:11 +00:00
|
|
|
return inode_has_perm(cred, file_inode(file), av, &ad);
|
2013-06-13 22:37:55 +00:00
|
|
|
}
|
|
|
|
|
2005-04-16 22:20:36 +00:00
|
|
|
/* Check whether a task can use an open file descriptor to
|
|
|
|
access an inode in a given way. Check access to the
|
|
|
|
descriptor itself, and then use dentry_has_perm to
|
|
|
|
check a particular permission to the file.
|
|
|
|
Access to the descriptor is implicitly granted if it
|
|
|
|
has the same SID as the process. If av is zero, then
|
|
|
|
access to the file is not checked, e.g. for cases
|
|
|
|
where only the descriptor is affected like seek. */
|
2008-11-13 23:39:21 +00:00
|
|
|
static int file_has_perm(const struct cred *cred,
|
|
|
|
struct file *file,
|
|
|
|
u32 av)
|
2005-04-16 22:20:36 +00:00
|
|
|
{
|
|
|
|
struct file_security_struct *fsec = file->f_security;
|
2013-01-23 22:07:38 +00:00
|
|
|
struct inode *inode = file_inode(file);
|
2009-07-14 16:14:09 +00:00
|
|
|
struct common_audit_data ad;
|
2008-11-13 23:39:21 +00:00
|
|
|
u32 sid = cred_sid(cred);
|
2005-04-16 22:20:36 +00:00
|
|
|
int rc;
|
|
|
|
|
2012-04-04 19:01:43 +00:00
|
|
|
ad.type = LSM_AUDIT_DATA_PATH;
|
2011-04-25 16:54:27 +00:00
|
|
|
ad.u.path = file->f_path;
|
2005-04-16 22:20:36 +00:00
|
|
|
|
2008-11-13 23:39:19 +00:00
|
|
|
if (sid != fsec->sid) {
|
|
|
|
rc = avc_has_perm(sid, fsec->sid,
|
2005-04-16 22:20:36 +00:00
|
|
|
SECCLASS_FD,
|
|
|
|
FD__USE,
|
|
|
|
&ad);
|
|
|
|
if (rc)
|
2008-11-13 23:39:21 +00:00
|
|
|
goto out;
|
2005-04-16 22:20:36 +00:00
|
|
|
}
|
|
|
|
|
|
|
|
/* av is zero if only checking access to the descriptor. */
|
2008-11-13 23:39:21 +00:00
|
|
|
rc = 0;
|
2005-04-16 22:20:36 +00:00
|
|
|
if (av)
|
2013-10-04 19:54:11 +00:00
|
|
|
rc = inode_has_perm(cred, inode, av, &ad);
|
2005-04-16 22:20:36 +00:00
|
|
|
|
2008-11-13 23:39:21 +00:00
|
|
|
out:
|
|
|
|
return rc;
|
2005-04-16 22:20:36 +00:00
|
|
|
}
|
|
|
|
|
|
|
|
/* Check whether a task can create a file. */
|
|
|
|
static int may_create(struct inode *dir,
|
|
|
|
struct dentry *dentry,
|
|
|
|
u16 tclass)
|
|
|
|
{
|
2010-04-22 18:46:19 +00:00
|
|
|
const struct task_security_struct *tsec = current_security();
|
2005-04-16 22:20:36 +00:00
|
|
|
struct inode_security_struct *dsec;
|
|
|
|
struct superblock_security_struct *sbsec;
|
2008-11-13 23:39:19 +00:00
|
|
|
u32 sid, newsid;
|
2009-07-14 16:14:09 +00:00
|
|
|
struct common_audit_data ad;
|
2005-04-16 22:20:36 +00:00
|
|
|
int rc;
|
|
|
|
|
|
|
|
dsec = dir->i_security;
|
|
|
|
sbsec = dir->i_sb->s_security;
|
|
|
|
|
2008-11-13 23:39:19 +00:00
|
|
|
sid = tsec->sid;
|
|
|
|
newsid = tsec->create_sid;
|
|
|
|
|
2012-04-04 19:01:43 +00:00
|
|
|
ad.type = LSM_AUDIT_DATA_DENTRY;
|
2011-04-25 17:10:27 +00:00
|
|
|
ad.u.dentry = dentry;
|
2005-04-16 22:20:36 +00:00
|
|
|
|
2008-11-13 23:39:19 +00:00
|
|
|
rc = avc_has_perm(sid, dsec->sid, SECCLASS_DIR,
|
2005-04-16 22:20:36 +00:00
|
|
|
DIR__ADD_NAME | DIR__SEARCH,
|
|
|
|
&ad);
|
|
|
|
if (rc)
|
|
|
|
return rc;
|
|
|
|
|
2012-10-09 14:56:25 +00:00
|
|
|
if (!newsid || !(sbsec->flags & SBLABEL_MNT)) {
|
2011-04-28 19:11:21 +00:00
|
|
|
rc = security_transition_sid(sid, dsec->sid, tclass,
|
|
|
|
&dentry->d_name, &newsid);
|
2005-04-16 22:20:36 +00:00
|
|
|
if (rc)
|
|
|
|
return rc;
|
|
|
|
}
|
|
|
|
|
2008-11-13 23:39:19 +00:00
|
|
|
rc = avc_has_perm(sid, newsid, tclass, FILE__CREATE, &ad);
|
2005-04-16 22:20:36 +00:00
|
|
|
if (rc)
|
|
|
|
return rc;
|
|
|
|
|
|
|
|
return avc_has_perm(newsid, sbsec->sid,
|
|
|
|
SECCLASS_FILESYSTEM,
|
|
|
|
FILESYSTEM__ASSOCIATE, &ad);
|
|
|
|
}
|
|
|
|
|
2006-06-26 07:24:57 +00:00
|
|
|
/* Check whether a task can create a key. */
|
|
|
|
static int may_create_key(u32 ksid,
|
|
|
|
struct task_struct *ctx)
|
|
|
|
{
|
2008-11-13 23:39:19 +00:00
|
|
|
u32 sid = task_sid(ctx);
|
2006-06-26 07:24:57 +00:00
|
|
|
|
2008-11-13 23:39:19 +00:00
|
|
|
return avc_has_perm(sid, ksid, SECCLASS_KEY, KEY__CREATE, NULL);
|
2006-06-26 07:24:57 +00:00
|
|
|
}
|
|
|
|
|
2008-04-17 17:17:49 +00:00
|
|
|
#define MAY_LINK 0
|
|
|
|
#define MAY_UNLINK 1
|
|
|
|
#define MAY_RMDIR 2
|
2005-04-16 22:20:36 +00:00
|
|
|
|
|
|
|
/* Check whether a task can link, unlink, or rmdir a file/directory. */
|
|
|
|
static int may_link(struct inode *dir,
|
|
|
|
struct dentry *dentry,
|
|
|
|
int kind)
|
|
|
|
|
|
|
|
{
|
|
|
|
struct inode_security_struct *dsec, *isec;
|
2009-07-14 16:14:09 +00:00
|
|
|
struct common_audit_data ad;
|
2008-11-13 23:39:19 +00:00
|
|
|
u32 sid = current_sid();
|
2005-04-16 22:20:36 +00:00
|
|
|
u32 av;
|
|
|
|
int rc;
|
|
|
|
|
|
|
|
dsec = dir->i_security;
|
|
|
|
isec = dentry->d_inode->i_security;
|
|
|
|
|
2012-04-04 19:01:43 +00:00
|
|
|
ad.type = LSM_AUDIT_DATA_DENTRY;
|
2011-04-25 17:10:27 +00:00
|
|
|
ad.u.dentry = dentry;
|
2005-04-16 22:20:36 +00:00
|
|
|
|
|
|
|
av = DIR__SEARCH;
|
|
|
|
av |= (kind ? DIR__REMOVE_NAME : DIR__ADD_NAME);
|
2008-11-13 23:39:19 +00:00
|
|
|
rc = avc_has_perm(sid, dsec->sid, SECCLASS_DIR, av, &ad);
|
2005-04-16 22:20:36 +00:00
|
|
|
if (rc)
|
|
|
|
return rc;
|
|
|
|
|
|
|
|
switch (kind) {
|
|
|
|
case MAY_LINK:
|
|
|
|
av = FILE__LINK;
|
|
|
|
break;
|
|
|
|
case MAY_UNLINK:
|
|
|
|
av = FILE__UNLINK;
|
|
|
|
break;
|
|
|
|
case MAY_RMDIR:
|
|
|
|
av = DIR__RMDIR;
|
|
|
|
break;
|
|
|
|
default:
|
2008-04-17 15:52:44 +00:00
|
|
|
printk(KERN_WARNING "SELinux: %s: unrecognized kind %d\n",
|
|
|
|
__func__, kind);
|
2005-04-16 22:20:36 +00:00
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
2008-11-13 23:39:19 +00:00
|
|
|
rc = avc_has_perm(sid, isec->sid, isec->sclass, av, &ad);
|
2005-04-16 22:20:36 +00:00
|
|
|
return rc;
|
|
|
|
}
|
|
|
|
|
|
|
|
static inline int may_rename(struct inode *old_dir,
|
|
|
|
struct dentry *old_dentry,
|
|
|
|
struct inode *new_dir,
|
|
|
|
struct dentry *new_dentry)
|
|
|
|
{
|
|
|
|
struct inode_security_struct *old_dsec, *new_dsec, *old_isec, *new_isec;
|
2009-07-14 16:14:09 +00:00
|
|
|
struct common_audit_data ad;
|
2008-11-13 23:39:19 +00:00
|
|
|
u32 sid = current_sid();
|
2005-04-16 22:20:36 +00:00
|
|
|
u32 av;
|
|
|
|
int old_is_dir, new_is_dir;
|
|
|
|
int rc;
|
|
|
|
|
|
|
|
old_dsec = old_dir->i_security;
|
|
|
|
old_isec = old_dentry->d_inode->i_security;
|
|
|
|
old_is_dir = S_ISDIR(old_dentry->d_inode->i_mode);
|
|
|
|
new_dsec = new_dir->i_security;
|
|
|
|
|
2012-04-04 19:01:43 +00:00
|
|
|
ad.type = LSM_AUDIT_DATA_DENTRY;
|
2005-04-16 22:20:36 +00:00
|
|
|
|
2011-04-25 17:10:27 +00:00
|
|
|
ad.u.dentry = old_dentry;
|
2008-11-13 23:39:19 +00:00
|
|
|
rc = avc_has_perm(sid, old_dsec->sid, SECCLASS_DIR,
|
2005-04-16 22:20:36 +00:00
|
|
|
DIR__REMOVE_NAME | DIR__SEARCH, &ad);
|
|
|
|
if (rc)
|
|
|
|
return rc;
|
2008-11-13 23:39:19 +00:00
|
|
|
rc = avc_has_perm(sid, old_isec->sid,
|
2005-04-16 22:20:36 +00:00
|
|
|
old_isec->sclass, FILE__RENAME, &ad);
|
|
|
|
if (rc)
|
|
|
|
return rc;
|
|
|
|
if (old_is_dir && new_dir != old_dir) {
|
2008-11-13 23:39:19 +00:00
|
|
|
rc = avc_has_perm(sid, old_isec->sid,
|
2005-04-16 22:20:36 +00:00
|
|
|
old_isec->sclass, DIR__REPARENT, &ad);
|
|
|
|
if (rc)
|
|
|
|
return rc;
|
|
|
|
}
|
|
|
|
|
2011-04-25 17:10:27 +00:00
|
|
|
ad.u.dentry = new_dentry;
|
2005-04-16 22:20:36 +00:00
|
|
|
av = DIR__ADD_NAME | DIR__SEARCH;
|
|
|
|
if (new_dentry->d_inode)
|
|
|
|
av |= DIR__REMOVE_NAME;
|
2008-11-13 23:39:19 +00:00
|
|
|
rc = avc_has_perm(sid, new_dsec->sid, SECCLASS_DIR, av, &ad);
|
2005-04-16 22:20:36 +00:00
|
|
|
if (rc)
|
|
|
|
return rc;
|
|
|
|
if (new_dentry->d_inode) {
|
|
|
|
new_isec = new_dentry->d_inode->i_security;
|
|
|
|
new_is_dir = S_ISDIR(new_dentry->d_inode->i_mode);
|
2008-11-13 23:39:19 +00:00
|
|
|
rc = avc_has_perm(sid, new_isec->sid,
|
2005-04-16 22:20:36 +00:00
|
|
|
new_isec->sclass,
|
|
|
|
(new_is_dir ? DIR__RMDIR : FILE__UNLINK), &ad);
|
|
|
|
if (rc)
|
|
|
|
return rc;
|
|
|
|
}
|
|
|
|
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
|
|
|
/* Check whether a task can perform a filesystem operation. */
|
2008-11-13 23:39:21 +00:00
|
|
|
static int superblock_has_perm(const struct cred *cred,
|
2005-04-16 22:20:36 +00:00
|
|
|
struct super_block *sb,
|
|
|
|
u32 perms,
|
2009-07-14 16:14:09 +00:00
|
|
|
struct common_audit_data *ad)
|
2005-04-16 22:20:36 +00:00
|
|
|
{
|
|
|
|
struct superblock_security_struct *sbsec;
|
2008-11-13 23:39:21 +00:00
|
|
|
u32 sid = cred_sid(cred);
|
2005-04-16 22:20:36 +00:00
|
|
|
|
|
|
|
sbsec = sb->s_security;
|
2008-11-13 23:39:19 +00:00
|
|
|
return avc_has_perm(sid, sbsec->sid, SECCLASS_FILESYSTEM, perms, ad);
|
2005-04-16 22:20:36 +00:00
|
|
|
}
|
|
|
|
|
|
|
|
/* Convert a Linux mode and permission mask to an access vector. */
|
|
|
|
static inline u32 file_mask_to_av(int mode, int mask)
|
|
|
|
{
|
|
|
|
u32 av = 0;
|
|
|
|
|
2011-07-26 00:49:29 +00:00
|
|
|
if (!S_ISDIR(mode)) {
|
2005-04-16 22:20:36 +00:00
|
|
|
if (mask & MAY_EXEC)
|
|
|
|
av |= FILE__EXECUTE;
|
|
|
|
if (mask & MAY_READ)
|
|
|
|
av |= FILE__READ;
|
|
|
|
|
|
|
|
if (mask & MAY_APPEND)
|
|
|
|
av |= FILE__APPEND;
|
|
|
|
else if (mask & MAY_WRITE)
|
|
|
|
av |= FILE__WRITE;
|
|
|
|
|
|
|
|
} else {
|
|
|
|
if (mask & MAY_EXEC)
|
|
|
|
av |= DIR__SEARCH;
|
|
|
|
if (mask & MAY_WRITE)
|
|
|
|
av |= DIR__WRITE;
|
|
|
|
if (mask & MAY_READ)
|
|
|
|
av |= DIR__READ;
|
|
|
|
}
|
|
|
|
|
|
|
|
return av;
|
|
|
|
}
|
|
|
|
|
2008-10-29 21:06:46 +00:00
|
|
|
/* Convert a Linux file to an access vector. */
|
|
|
|
static inline u32 file_to_av(struct file *file)
|
|
|
|
{
|
|
|
|
u32 av = 0;
|
|
|
|
|
|
|
|
if (file->f_mode & FMODE_READ)
|
|
|
|
av |= FILE__READ;
|
|
|
|
if (file->f_mode & FMODE_WRITE) {
|
|
|
|
if (file->f_flags & O_APPEND)
|
|
|
|
av |= FILE__APPEND;
|
|
|
|
else
|
|
|
|
av |= FILE__WRITE;
|
|
|
|
}
|
|
|
|
if (!av) {
|
|
|
|
/*
|
|
|
|
* Special file opened with flags 3 for ioctl-only use.
|
|
|
|
*/
|
|
|
|
av = FILE__IOCTL;
|
|
|
|
}
|
|
|
|
|
|
|
|
return av;
|
|
|
|
}
|
|
|
|
|
2008-02-28 17:58:40 +00:00
|
|
|
/*
|
2008-10-29 21:06:46 +00:00
|
|
|
* Convert a file to an access vector and include the correct open
|
2008-02-28 17:58:40 +00:00
|
|
|
* open permission.
|
|
|
|
*/
|
2008-10-29 21:06:46 +00:00
|
|
|
static inline u32 open_file_to_av(struct file *file)
|
2008-02-28 17:58:40 +00:00
|
|
|
{
|
2008-10-29 21:06:46 +00:00
|
|
|
u32 av = file_to_av(file);
|
2008-02-28 17:58:40 +00:00
|
|
|
|
2010-07-23 15:44:09 +00:00
|
|
|
if (selinux_policycap_openperm)
|
|
|
|
av |= FILE__OPEN;
|
|
|
|
|
2008-02-28 17:58:40 +00:00
|
|
|
return av;
|
|
|
|
}
|
|
|
|
|
2005-04-16 22:20:36 +00:00
|
|
|
/* Hook functions begin here. */
|
|
|
|
|
2009-05-07 09:26:19 +00:00
|
|
|
static int selinux_ptrace_access_check(struct task_struct *child,
|
security: Fix setting of PF_SUPERPRIV by __capable()
Fix the setting of PF_SUPERPRIV by __capable() as it could corrupt the flags
the target process if that is not the current process and it is trying to
change its own flags in a different way at the same time.
__capable() is using neither atomic ops nor locking to protect t->flags. This
patch removes __capable() and introduces has_capability() that doesn't set
PF_SUPERPRIV on the process being queried.
This patch further splits security_ptrace() in two:
(1) security_ptrace_may_access(). This passes judgement on whether one
process may access another only (PTRACE_MODE_ATTACH for ptrace() and
PTRACE_MODE_READ for /proc), and takes a pointer to the child process.
current is the parent.
(2) security_ptrace_traceme(). This passes judgement on PTRACE_TRACEME only,
and takes only a pointer to the parent process. current is the child.
In Smack and commoncap, this uses has_capability() to determine whether
the parent will be permitted to use PTRACE_ATTACH if normal checks fail.
This does not set PF_SUPERPRIV.
Two of the instances of __capable() actually only act on current, and so have
been changed to calls to capable().
Of the places that were using __capable():
(1) The OOM killer calls __capable() thrice when weighing the killability of a
process. All of these now use has_capability().
(2) cap_ptrace() and smack_ptrace() were using __capable() to check to see
whether the parent was allowed to trace any process. As mentioned above,
these have been split. For PTRACE_ATTACH and /proc, capable() is now
used, and for PTRACE_TRACEME, has_capability() is used.
(3) cap_safe_nice() only ever saw current, so now uses capable().
(4) smack_setprocattr() rejected accesses to tasks other than current just
after calling __capable(), so the order of these two tests have been
switched and capable() is used instead.
(5) In smack_file_send_sigiotask(), we need to allow privileged processes to
receive SIGIO on files they're manipulating.
(6) In smack_task_wait(), we let a process wait for a privileged process,
whether or not the process doing the waiting is privileged.
I've tested this with the LTP SELinux and syscalls testscripts.
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Acked-by: Casey Schaufler <casey@schaufler-ca.com>
Acked-by: Andrew G. Morgan <morgan@kernel.org>
Acked-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: James Morris <jmorris@namei.org>
2008-08-14 10:37:28 +00:00
|
|
|
unsigned int mode)
|
2005-04-16 22:20:36 +00:00
|
|
|
{
|
|
|
|
int rc;
|
|
|
|
|
2009-05-07 09:26:19 +00:00
|
|
|
rc = cap_ptrace_access_check(child, mode);
|
2005-04-16 22:20:36 +00:00
|
|
|
if (rc)
|
|
|
|
return rc;
|
|
|
|
|
2012-01-03 17:25:15 +00:00
|
|
|
if (mode & PTRACE_MODE_READ) {
|
2008-11-13 23:39:19 +00:00
|
|
|
u32 sid = current_sid();
|
|
|
|
u32 csid = task_sid(child);
|
|
|
|
return avc_has_perm(sid, csid, SECCLASS_FILE, FILE__READ, NULL);
|
Security: split proc ptrace checking into read vs. attach
Enable security modules to distinguish reading of process state via
proc from full ptrace access by renaming ptrace_may_attach to
ptrace_may_access and adding a mode argument indicating whether only
read access or full attach access is requested. This allows security
modules to permit access to reading process state without granting
full ptrace access. The base DAC/capability checking remains unchanged.
Read access to /proc/pid/mem continues to apply a full ptrace attach
check since check_mem_permission() already requires the current task
to already be ptracing the target. The other ptrace checks within
proc for elements like environ, maps, and fds are changed to pass the
read mode instead of attach.
In the SELinux case, we model such reading of process state as a
reading of a proc file labeled with the target process' label. This
enables SELinux policy to permit such reading of process state without
permitting control or manipulation of the target process, as there are
a number of cases where programs probe for such information via proc
but do not need to be able to control the target (e.g. procps,
lsof, PolicyKit, ConsoleKit). At present we have to choose between
allowing full ptrace in policy (more permissive than required/desired)
or breaking functionality (or in some cases just silencing the denials
via dontaudit rules but this can hide genuine attacks).
This version of the patch incorporates comments from Casey Schaufler
(change/replace existing ptrace_may_attach interface, pass access
mode), and Chris Wright (provide greater consistency in the checking).
Note that like their predecessors __ptrace_may_attach and
ptrace_may_attach, the __ptrace_may_access and ptrace_may_access
interfaces use different return value conventions from each other (0
or -errno vs. 1 or 0). I retained this difference to avoid any
changes to the caller logic but made the difference clearer by
changing the latter interface to return a bool rather than an int and
by adding a comment about it to ptrace.h for any future callers.
Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov>
Acked-by: Chris Wright <chrisw@sous-sol.org>
Signed-off-by: James Morris <jmorris@namei.org>
2008-05-19 12:32:49 +00:00
|
|
|
}
|
|
|
|
|
2008-11-13 23:39:26 +00:00
|
|
|
return current_has_perm(child, PROCESS__PTRACE);
|
security: Fix setting of PF_SUPERPRIV by __capable()
Fix the setting of PF_SUPERPRIV by __capable() as it could corrupt the flags
the target process if that is not the current process and it is trying to
change its own flags in a different way at the same time.
__capable() is using neither atomic ops nor locking to protect t->flags. This
patch removes __capable() and introduces has_capability() that doesn't set
PF_SUPERPRIV on the process being queried.
This patch further splits security_ptrace() in two:
(1) security_ptrace_may_access(). This passes judgement on whether one
process may access another only (PTRACE_MODE_ATTACH for ptrace() and
PTRACE_MODE_READ for /proc), and takes a pointer to the child process.
current is the parent.
(2) security_ptrace_traceme(). This passes judgement on PTRACE_TRACEME only,
and takes only a pointer to the parent process. current is the child.
In Smack and commoncap, this uses has_capability() to determine whether
the parent will be permitted to use PTRACE_ATTACH if normal checks fail.
This does not set PF_SUPERPRIV.
Two of the instances of __capable() actually only act on current, and so have
been changed to calls to capable().
Of the places that were using __capable():
(1) The OOM killer calls __capable() thrice when weighing the killability of a
process. All of these now use has_capability().
(2) cap_ptrace() and smack_ptrace() were using __capable() to check to see
whether the parent was allowed to trace any process. As mentioned above,
these have been split. For PTRACE_ATTACH and /proc, capable() is now
used, and for PTRACE_TRACEME, has_capability() is used.
(3) cap_safe_nice() only ever saw current, so now uses capable().
(4) smack_setprocattr() rejected accesses to tasks other than current just
after calling __capable(), so the order of these two tests have been
switched and capable() is used instead.
(5) In smack_file_send_sigiotask(), we need to allow privileged processes to
receive SIGIO on files they're manipulating.
(6) In smack_task_wait(), we let a process wait for a privileged process,
whether or not the process doing the waiting is privileged.
I've tested this with the LTP SELinux and syscalls testscripts.
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Acked-by: Casey Schaufler <casey@schaufler-ca.com>
Acked-by: Andrew G. Morgan <morgan@kernel.org>
Acked-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: James Morris <jmorris@namei.org>
2008-08-14 10:37:28 +00:00
|
|
|
}
|
|
|
|
|
|
|
|
static int selinux_ptrace_traceme(struct task_struct *parent)
|
|
|
|
{
|
|
|
|
int rc;
|
|
|
|
|
2009-02-12 20:01:04 +00:00
|
|
|
rc = cap_ptrace_traceme(parent);
|
security: Fix setting of PF_SUPERPRIV by __capable()
Fix the setting of PF_SUPERPRIV by __capable() as it could corrupt the flags
the target process if that is not the current process and it is trying to
change its own flags in a different way at the same time.
__capable() is using neither atomic ops nor locking to protect t->flags. This
patch removes __capable() and introduces has_capability() that doesn't set
PF_SUPERPRIV on the process being queried.
This patch further splits security_ptrace() in two:
(1) security_ptrace_may_access(). This passes judgement on whether one
process may access another only (PTRACE_MODE_ATTACH for ptrace() and
PTRACE_MODE_READ for /proc), and takes a pointer to the child process.
current is the parent.
(2) security_ptrace_traceme(). This passes judgement on PTRACE_TRACEME only,
and takes only a pointer to the parent process. current is the child.
In Smack and commoncap, this uses has_capability() to determine whether
the parent will be permitted to use PTRACE_ATTACH if normal checks fail.
This does not set PF_SUPERPRIV.
Two of the instances of __capable() actually only act on current, and so have
been changed to calls to capable().
Of the places that were using __capable():
(1) The OOM killer calls __capable() thrice when weighing the killability of a
process. All of these now use has_capability().
(2) cap_ptrace() and smack_ptrace() were using __capable() to check to see
whether the parent was allowed to trace any process. As mentioned above,
these have been split. For PTRACE_ATTACH and /proc, capable() is now
used, and for PTRACE_TRACEME, has_capability() is used.
(3) cap_safe_nice() only ever saw current, so now uses capable().
(4) smack_setprocattr() rejected accesses to tasks other than current just
after calling __capable(), so the order of these two tests have been
switched and capable() is used instead.
(5) In smack_file_send_sigiotask(), we need to allow privileged processes to
receive SIGIO on files they're manipulating.
(6) In smack_task_wait(), we let a process wait for a privileged process,
whether or not the process doing the waiting is privileged.
I've tested this with the LTP SELinux and syscalls testscripts.
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Acked-by: Casey Schaufler <casey@schaufler-ca.com>
Acked-by: Andrew G. Morgan <morgan@kernel.org>
Acked-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: James Morris <jmorris@namei.org>
2008-08-14 10:37:28 +00:00
|
|
|
if (rc)
|
|
|
|
return rc;
|
|
|
|
|
|
|
|
return task_has_perm(parent, current, PROCESS__PTRACE);
|
2005-04-16 22:20:36 +00:00
|
|
|
}
|
|
|
|
|
|
|
|
static int selinux_capget(struct task_struct *target, kernel_cap_t *effective,
|
2008-04-17 17:17:49 +00:00
|
|
|
kernel_cap_t *inheritable, kernel_cap_t *permitted)
|
2005-04-16 22:20:36 +00:00
|
|
|
{
|
|
|
|
int error;
|
|
|
|
|
2008-11-13 23:39:26 +00:00
|
|
|
error = current_has_perm(target, PROCESS__GETCAP);
|
2005-04-16 22:20:36 +00:00
|
|
|
if (error)
|
|
|
|
return error;
|
|
|
|
|
2009-02-12 20:01:04 +00:00
|
|
|
return cap_capget(target, effective, inheritable, permitted);
|
2005-04-16 22:20:36 +00:00
|
|
|
}
|
|
|
|
|
CRED: Inaugurate COW credentials
Inaugurate copy-on-write credentials management. This uses RCU to manage the
credentials pointer in the task_struct with respect to accesses by other tasks.
A process may only modify its own credentials, and so does not need locking to
access or modify its own credentials.
A mutex (cred_replace_mutex) is added to the task_struct to control the effect
of PTRACE_ATTACHED on credential calculations, particularly with respect to
execve().
With this patch, the contents of an active credentials struct may not be
changed directly; rather a new set of credentials must be prepared, modified
and committed using something like the following sequence of events:
struct cred *new = prepare_creds();
int ret = blah(new);
if (ret < 0) {
abort_creds(new);
return ret;
}
return commit_creds(new);
There are some exceptions to this rule: the keyrings pointed to by the active
credentials may be instantiated - keyrings violate the COW rule as managing
COW keyrings is tricky, given that it is possible for a task to directly alter
the keys in a keyring in use by another task.
To help enforce this, various pointers to sets of credentials, such as those in
the task_struct, are declared const. The purpose of this is compile-time
discouragement of altering credentials through those pointers. Once a set of
credentials has been made public through one of these pointers, it may not be
modified, except under special circumstances:
(1) Its reference count may incremented and decremented.
(2) The keyrings to which it points may be modified, but not replaced.
The only safe way to modify anything else is to create a replacement and commit
using the functions described in Documentation/credentials.txt (which will be
added by a later patch).
This patch and the preceding patches have been tested with the LTP SELinux
testsuite.
This patch makes several logical sets of alteration:
(1) execve().
This now prepares and commits credentials in various places in the
security code rather than altering the current creds directly.
(2) Temporary credential overrides.
do_coredump() and sys_faccessat() now prepare their own credentials and
temporarily override the ones currently on the acting thread, whilst
preventing interference from other threads by holding cred_replace_mutex
on the thread being dumped.
This will be replaced in a future patch by something that hands down the
credentials directly to the functions being called, rather than altering
the task's objective credentials.
(3) LSM interface.
A number of functions have been changed, added or removed:
(*) security_capset_check(), ->capset_check()
(*) security_capset_set(), ->capset_set()
Removed in favour of security_capset().
(*) security_capset(), ->capset()
New. This is passed a pointer to the new creds, a pointer to the old
creds and the proposed capability sets. It should fill in the new
creds or return an error. All pointers, barring the pointer to the
new creds, are now const.
(*) security_bprm_apply_creds(), ->bprm_apply_creds()
Changed; now returns a value, which will cause the process to be
killed if it's an error.
(*) security_task_alloc(), ->task_alloc_security()
Removed in favour of security_prepare_creds().
(*) security_cred_free(), ->cred_free()
New. Free security data attached to cred->security.
(*) security_prepare_creds(), ->cred_prepare()
New. Duplicate any security data attached to cred->security.
(*) security_commit_creds(), ->cred_commit()
New. Apply any security effects for the upcoming installation of new
security by commit_creds().
(*) security_task_post_setuid(), ->task_post_setuid()
Removed in favour of security_task_fix_setuid().
(*) security_task_fix_setuid(), ->task_fix_setuid()
Fix up the proposed new credentials for setuid(). This is used by
cap_set_fix_setuid() to implicitly adjust capabilities in line with
setuid() changes. Changes are made to the new credentials, rather
than the task itself as in security_task_post_setuid().
(*) security_task_reparent_to_init(), ->task_reparent_to_init()
Removed. Instead the task being reparented to init is referred
directly to init's credentials.
NOTE! This results in the loss of some state: SELinux's osid no
longer records the sid of the thread that forked it.
(*) security_key_alloc(), ->key_alloc()
(*) security_key_permission(), ->key_permission()
Changed. These now take cred pointers rather than task pointers to
refer to the security context.
(4) sys_capset().
This has been simplified and uses less locking. The LSM functions it
calls have been merged.
(5) reparent_to_kthreadd().
This gives the current thread the same credentials as init by simply using
commit_thread() to point that way.
(6) __sigqueue_alloc() and switch_uid()
__sigqueue_alloc() can't stop the target task from changing its creds
beneath it, so this function gets a reference to the currently applicable
user_struct which it then passes into the sigqueue struct it returns if
successful.
switch_uid() is now called from commit_creds(), and possibly should be
folded into that. commit_creds() should take care of protecting
__sigqueue_alloc().
(7) [sg]et[ug]id() and co and [sg]et_current_groups.
The set functions now all use prepare_creds(), commit_creds() and
abort_creds() to build and check a new set of credentials before applying
it.
security_task_set[ug]id() is called inside the prepared section. This
guarantees that nothing else will affect the creds until we've finished.
The calling of set_dumpable() has been moved into commit_creds().
Much of the functionality of set_user() has been moved into
commit_creds().
The get functions all simply access the data directly.
(8) security_task_prctl() and cap_task_prctl().
security_task_prctl() has been modified to return -ENOSYS if it doesn't
want to handle a function, or otherwise return the return value directly
rather than through an argument.
Additionally, cap_task_prctl() now prepares a new set of credentials, even
if it doesn't end up using it.
(9) Keyrings.
A number of changes have been made to the keyrings code:
(a) switch_uid_keyring(), copy_keys(), exit_keys() and suid_keys() have
all been dropped and built in to the credentials functions directly.
They may want separating out again later.
(b) key_alloc() and search_process_keyrings() now take a cred pointer
rather than a task pointer to specify the security context.
(c) copy_creds() gives a new thread within the same thread group a new
thread keyring if its parent had one, otherwise it discards the thread
keyring.
(d) The authorisation key now points directly to the credentials to extend
the search into rather pointing to the task that carries them.
(e) Installing thread, process or session keyrings causes a new set of
credentials to be created, even though it's not strictly necessary for
process or session keyrings (they're shared).
(10) Usermode helper.
The usermode helper code now carries a cred struct pointer in its
subprocess_info struct instead of a new session keyring pointer. This set
of credentials is derived from init_cred and installed on the new process
after it has been cloned.
call_usermodehelper_setup() allocates the new credentials and
call_usermodehelper_freeinfo() discards them if they haven't been used. A
special cred function (prepare_usermodeinfo_creds()) is provided
specifically for call_usermodehelper_setup() to call.
call_usermodehelper_setkeys() adjusts the credentials to sport the
supplied keyring as the new session keyring.
(11) SELinux.
SELinux has a number of changes, in addition to those to support the LSM
interface changes mentioned above:
(a) selinux_setprocattr() no longer does its check for whether the
current ptracer can access processes with the new SID inside the lock
that covers getting the ptracer's SID. Whilst this lock ensures that
the check is done with the ptracer pinned, the result is only valid
until the lock is released, so there's no point doing it inside the
lock.
(12) is_single_threaded().
This function has been extracted from selinux_setprocattr() and put into
a file of its own in the lib/ directory as join_session_keyring() now
wants to use it too.
The code in SELinux just checked to see whether a task shared mm_structs
with other tasks (CLONE_VM), but that isn't good enough. We really want
to know if they're part of the same thread group (CLONE_THREAD).
(13) nfsd.
The NFS server daemon now has to use the COW credentials to set the
credentials it is going to use. It really needs to pass the credentials
down to the functions it calls, but it can't do that until other patches
in this series have been applied.
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: James Morris <jmorris@namei.org>
Signed-off-by: James Morris <jmorris@namei.org>
2008-11-13 23:39:23 +00:00
|
|
|
static int selinux_capset(struct cred *new, const struct cred *old,
|
|
|
|
const kernel_cap_t *effective,
|
|
|
|
const kernel_cap_t *inheritable,
|
|
|
|
const kernel_cap_t *permitted)
|
2005-04-16 22:20:36 +00:00
|
|
|
{
|
|
|
|
int error;
|
|
|
|
|
2009-02-12 20:01:04 +00:00
|
|
|
error = cap_capset(new, old,
|
CRED: Inaugurate COW credentials
Inaugurate copy-on-write credentials management. This uses RCU to manage the
credentials pointer in the task_struct with respect to accesses by other tasks.
A process may only modify its own credentials, and so does not need locking to
access or modify its own credentials.
A mutex (cred_replace_mutex) is added to the task_struct to control the effect
of PTRACE_ATTACHED on credential calculations, particularly with respect to
execve().
With this patch, the contents of an active credentials struct may not be
changed directly; rather a new set of credentials must be prepared, modified
and committed using something like the following sequence of events:
struct cred *new = prepare_creds();
int ret = blah(new);
if (ret < 0) {
abort_creds(new);
return ret;
}
return commit_creds(new);
There are some exceptions to this rule: the keyrings pointed to by the active
credentials may be instantiated - keyrings violate the COW rule as managing
COW keyrings is tricky, given that it is possible for a task to directly alter
the keys in a keyring in use by another task.
To help enforce this, various pointers to sets of credentials, such as those in
the task_struct, are declared const. The purpose of this is compile-time
discouragement of altering credentials through those pointers. Once a set of
credentials has been made public through one of these pointers, it may not be
modified, except under special circumstances:
(1) Its reference count may incremented and decremented.
(2) The keyrings to which it points may be modified, but not replaced.
The only safe way to modify anything else is to create a replacement and commit
using the functions described in Documentation/credentials.txt (which will be
added by a later patch).
This patch and the preceding patches have been tested with the LTP SELinux
testsuite.
This patch makes several logical sets of alteration:
(1) execve().
This now prepares and commits credentials in various places in the
security code rather than altering the current creds directly.
(2) Temporary credential overrides.
do_coredump() and sys_faccessat() now prepare their own credentials and
temporarily override the ones currently on the acting thread, whilst
preventing interference from other threads by holding cred_replace_mutex
on the thread being dumped.
This will be replaced in a future patch by something that hands down the
credentials directly to the functions being called, rather than altering
the task's objective credentials.
(3) LSM interface.
A number of functions have been changed, added or removed:
(*) security_capset_check(), ->capset_check()
(*) security_capset_set(), ->capset_set()
Removed in favour of security_capset().
(*) security_capset(), ->capset()
New. This is passed a pointer to the new creds, a pointer to the old
creds and the proposed capability sets. It should fill in the new
creds or return an error. All pointers, barring the pointer to the
new creds, are now const.
(*) security_bprm_apply_creds(), ->bprm_apply_creds()
Changed; now returns a value, which will cause the process to be
killed if it's an error.
(*) security_task_alloc(), ->task_alloc_security()
Removed in favour of security_prepare_creds().
(*) security_cred_free(), ->cred_free()
New. Free security data attached to cred->security.
(*) security_prepare_creds(), ->cred_prepare()
New. Duplicate any security data attached to cred->security.
(*) security_commit_creds(), ->cred_commit()
New. Apply any security effects for the upcoming installation of new
security by commit_creds().
(*) security_task_post_setuid(), ->task_post_setuid()
Removed in favour of security_task_fix_setuid().
(*) security_task_fix_setuid(), ->task_fix_setuid()
Fix up the proposed new credentials for setuid(). This is used by
cap_set_fix_setuid() to implicitly adjust capabilities in line with
setuid() changes. Changes are made to the new credentials, rather
than the task itself as in security_task_post_setuid().
(*) security_task_reparent_to_init(), ->task_reparent_to_init()
Removed. Instead the task being reparented to init is referred
directly to init's credentials.
NOTE! This results in the loss of some state: SELinux's osid no
longer records the sid of the thread that forked it.
(*) security_key_alloc(), ->key_alloc()
(*) security_key_permission(), ->key_permission()
Changed. These now take cred pointers rather than task pointers to
refer to the security context.
(4) sys_capset().
This has been simplified and uses less locking. The LSM functions it
calls have been merged.
(5) reparent_to_kthreadd().
This gives the current thread the same credentials as init by simply using
commit_thread() to point that way.
(6) __sigqueue_alloc() and switch_uid()
__sigqueue_alloc() can't stop the target task from changing its creds
beneath it, so this function gets a reference to the currently applicable
user_struct which it then passes into the sigqueue struct it returns if
successful.
switch_uid() is now called from commit_creds(), and possibly should be
folded into that. commit_creds() should take care of protecting
__sigqueue_alloc().
(7) [sg]et[ug]id() and co and [sg]et_current_groups.
The set functions now all use prepare_creds(), commit_creds() and
abort_creds() to build and check a new set of credentials before applying
it.
security_task_set[ug]id() is called inside the prepared section. This
guarantees that nothing else will affect the creds until we've finished.
The calling of set_dumpable() has been moved into commit_creds().
Much of the functionality of set_user() has been moved into
commit_creds().
The get functions all simply access the data directly.
(8) security_task_prctl() and cap_task_prctl().
security_task_prctl() has been modified to return -ENOSYS if it doesn't
want to handle a function, or otherwise return the return value directly
rather than through an argument.
Additionally, cap_task_prctl() now prepares a new set of credentials, even
if it doesn't end up using it.
(9) Keyrings.
A number of changes have been made to the keyrings code:
(a) switch_uid_keyring(), copy_keys(), exit_keys() and suid_keys() have
all been dropped and built in to the credentials functions directly.
They may want separating out again later.
(b) key_alloc() and search_process_keyrings() now take a cred pointer
rather than a task pointer to specify the security context.
(c) copy_creds() gives a new thread within the same thread group a new
thread keyring if its parent had one, otherwise it discards the thread
keyring.
(d) The authorisation key now points directly to the credentials to extend
the search into rather pointing to the task that carries them.
(e) Installing thread, process or session keyrings causes a new set of
credentials to be created, even though it's not strictly necessary for
process or session keyrings (they're shared).
(10) Usermode helper.
The usermode helper code now carries a cred struct pointer in its
subprocess_info struct instead of a new session keyring pointer. This set
of credentials is derived from init_cred and installed on the new process
after it has been cloned.
call_usermodehelper_setup() allocates the new credentials and
call_usermodehelper_freeinfo() discards them if they haven't been used. A
special cred function (prepare_usermodeinfo_creds()) is provided
specifically for call_usermodehelper_setup() to call.
call_usermodehelper_setkeys() adjusts the credentials to sport the
supplied keyring as the new session keyring.
(11) SELinux.
SELinux has a number of changes, in addition to those to support the LSM
interface changes mentioned above:
(a) selinux_setprocattr() no longer does its check for whether the
current ptracer can access processes with the new SID inside the lock
that covers getting the ptracer's SID. Whilst this lock ensures that
the check is done with the ptracer pinned, the result is only valid
until the lock is released, so there's no point doing it inside the
lock.
(12) is_single_threaded().
This function has been extracted from selinux_setprocattr() and put into
a file of its own in the lib/ directory as join_session_keyring() now
wants to use it too.
The code in SELinux just checked to see whether a task shared mm_structs
with other tasks (CLONE_VM), but that isn't good enough. We really want
to know if they're part of the same thread group (CLONE_THREAD).
(13) nfsd.
The NFS server daemon now has to use the COW credentials to set the
credentials it is going to use. It really needs to pass the credentials
down to the functions it calls, but it can't do that until other patches
in this series have been applied.
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: James Morris <jmorris@namei.org>
Signed-off-by: James Morris <jmorris@namei.org>
2008-11-13 23:39:23 +00:00
|
|
|
effective, inheritable, permitted);
|
2005-04-16 22:20:36 +00:00
|
|
|
if (error)
|
|
|
|
return error;
|
|
|
|
|
CRED: Inaugurate COW credentials
Inaugurate copy-on-write credentials management. This uses RCU to manage the
credentials pointer in the task_struct with respect to accesses by other tasks.
A process may only modify its own credentials, and so does not need locking to
access or modify its own credentials.
A mutex (cred_replace_mutex) is added to the task_struct to control the effect
of PTRACE_ATTACHED on credential calculations, particularly with respect to
execve().
With this patch, the contents of an active credentials struct may not be
changed directly; rather a new set of credentials must be prepared, modified
and committed using something like the following sequence of events:
struct cred *new = prepare_creds();
int ret = blah(new);
if (ret < 0) {
abort_creds(new);
return ret;
}
return commit_creds(new);
There are some exceptions to this rule: the keyrings pointed to by the active
credentials may be instantiated - keyrings violate the COW rule as managing
COW keyrings is tricky, given that it is possible for a task to directly alter
the keys in a keyring in use by another task.
To help enforce this, various pointers to sets of credentials, such as those in
the task_struct, are declared const. The purpose of this is compile-time
discouragement of altering credentials through those pointers. Once a set of
credentials has been made public through one of these pointers, it may not be
modified, except under special circumstances:
(1) Its reference count may incremented and decremented.
(2) The keyrings to which it points may be modified, but not replaced.
The only safe way to modify anything else is to create a replacement and commit
using the functions described in Documentation/credentials.txt (which will be
added by a later patch).
This patch and the preceding patches have been tested with the LTP SELinux
testsuite.
This patch makes several logical sets of alteration:
(1) execve().
This now prepares and commits credentials in various places in the
security code rather than altering the current creds directly.
(2) Temporary credential overrides.
do_coredump() and sys_faccessat() now prepare their own credentials and
temporarily override the ones currently on the acting thread, whilst
preventing interference from other threads by holding cred_replace_mutex
on the thread being dumped.
This will be replaced in a future patch by something that hands down the
credentials directly to the functions being called, rather than altering
the task's objective credentials.
(3) LSM interface.
A number of functions have been changed, added or removed:
(*) security_capset_check(), ->capset_check()
(*) security_capset_set(), ->capset_set()
Removed in favour of security_capset().
(*) security_capset(), ->capset()
New. This is passed a pointer to the new creds, a pointer to the old
creds and the proposed capability sets. It should fill in the new
creds or return an error. All pointers, barring the pointer to the
new creds, are now const.
(*) security_bprm_apply_creds(), ->bprm_apply_creds()
Changed; now returns a value, which will cause the process to be
killed if it's an error.
(*) security_task_alloc(), ->task_alloc_security()
Removed in favour of security_prepare_creds().
(*) security_cred_free(), ->cred_free()
New. Free security data attached to cred->security.
(*) security_prepare_creds(), ->cred_prepare()
New. Duplicate any security data attached to cred->security.
(*) security_commit_creds(), ->cred_commit()
New. Apply any security effects for the upcoming installation of new
security by commit_creds().
(*) security_task_post_setuid(), ->task_post_setuid()
Removed in favour of security_task_fix_setuid().
(*) security_task_fix_setuid(), ->task_fix_setuid()
Fix up the proposed new credentials for setuid(). This is used by
cap_set_fix_setuid() to implicitly adjust capabilities in line with
setuid() changes. Changes are made to the new credentials, rather
than the task itself as in security_task_post_setuid().
(*) security_task_reparent_to_init(), ->task_reparent_to_init()
Removed. Instead the task being reparented to init is referred
directly to init's credentials.
NOTE! This results in the loss of some state: SELinux's osid no
longer records the sid of the thread that forked it.
(*) security_key_alloc(), ->key_alloc()
(*) security_key_permission(), ->key_permission()
Changed. These now take cred pointers rather than task pointers to
refer to the security context.
(4) sys_capset().
This has been simplified and uses less locking. The LSM functions it
calls have been merged.
(5) reparent_to_kthreadd().
This gives the current thread the same credentials as init by simply using
commit_thread() to point that way.
(6) __sigqueue_alloc() and switch_uid()
__sigqueue_alloc() can't stop the target task from changing its creds
beneath it, so this function gets a reference to the currently applicable
user_struct which it then passes into the sigqueue struct it returns if
successful.
switch_uid() is now called from commit_creds(), and possibly should be
folded into that. commit_creds() should take care of protecting
__sigqueue_alloc().
(7) [sg]et[ug]id() and co and [sg]et_current_groups.
The set functions now all use prepare_creds(), commit_creds() and
abort_creds() to build and check a new set of credentials before applying
it.
security_task_set[ug]id() is called inside the prepared section. This
guarantees that nothing else will affect the creds until we've finished.
The calling of set_dumpable() has been moved into commit_creds().
Much of the functionality of set_user() has been moved into
commit_creds().
The get functions all simply access the data directly.
(8) security_task_prctl() and cap_task_prctl().
security_task_prctl() has been modified to return -ENOSYS if it doesn't
want to handle a function, or otherwise return the return value directly
rather than through an argument.
Additionally, cap_task_prctl() now prepares a new set of credentials, even
if it doesn't end up using it.
(9) Keyrings.
A number of changes have been made to the keyrings code:
(a) switch_uid_keyring(), copy_keys(), exit_keys() and suid_keys() have
all been dropped and built in to the credentials functions directly.
They may want separating out again later.
(b) key_alloc() and search_process_keyrings() now take a cred pointer
rather than a task pointer to specify the security context.
(c) copy_creds() gives a new thread within the same thread group a new
thread keyring if its parent had one, otherwise it discards the thread
keyring.
(d) The authorisation key now points directly to the credentials to extend
the search into rather pointing to the task that carries them.
(e) Installing thread, process or session keyrings causes a new set of
credentials to be created, even though it's not strictly necessary for
process or session keyrings (they're shared).
(10) Usermode helper.
The usermode helper code now carries a cred struct pointer in its
subprocess_info struct instead of a new session keyring pointer. This set
of credentials is derived from init_cred and installed on the new process
after it has been cloned.
call_usermodehelper_setup() allocates the new credentials and
call_usermodehelper_freeinfo() discards them if they haven't been used. A
special cred function (prepare_usermodeinfo_creds()) is provided
specifically for call_usermodehelper_setup() to call.
call_usermodehelper_setkeys() adjusts the credentials to sport the
supplied keyring as the new session keyring.
(11) SELinux.
SELinux has a number of changes, in addition to those to support the LSM
interface changes mentioned above:
(a) selinux_setprocattr() no longer does its check for whether the
current ptracer can access processes with the new SID inside the lock
that covers getting the ptracer's SID. Whilst this lock ensures that
the check is done with the ptracer pinned, the result is only valid
until the lock is released, so there's no point doing it inside the
lock.
(12) is_single_threaded().
This function has been extracted from selinux_setprocattr() and put into
a file of its own in the lib/ directory as join_session_keyring() now
wants to use it too.
The code in SELinux just checked to see whether a task shared mm_structs
with other tasks (CLONE_VM), but that isn't good enough. We really want
to know if they're part of the same thread group (CLONE_THREAD).
(13) nfsd.
The NFS server daemon now has to use the COW credentials to set the
credentials it is going to use. It really needs to pass the credentials
down to the functions it calls, but it can't do that until other patches
in this series have been applied.
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: James Morris <jmorris@namei.org>
Signed-off-by: James Morris <jmorris@namei.org>
2008-11-13 23:39:23 +00:00
|
|
|
return cred_has_perm(old, new, PROCESS__SETCAP);
|
2005-04-16 22:20:36 +00:00
|
|
|
}
|
|
|
|
|
2009-01-29 23:05:06 +00:00
|
|
|
/*
|
|
|
|
* (This comment used to live with the selinux_task_setuid hook,
|
|
|
|
* which was removed).
|
|
|
|
*
|
|
|
|
* Since setuid only affects the current process, and since the SELinux
|
|
|
|
* controls are not based on the Linux identity attributes, SELinux does not
|
|
|
|
* need to control this operation. However, SELinux does control the use of
|
|
|
|
* the CAP_SETUID and CAP_SETGID capabilities using the capable hook.
|
|
|
|
*/
|
|
|
|
|
2012-01-03 17:25:14 +00:00
|
|
|
static int selinux_capable(const struct cred *cred, struct user_namespace *ns,
|
|
|
|
int cap, int audit)
|
2005-04-16 22:20:36 +00:00
|
|
|
{
|
|
|
|
int rc;
|
|
|
|
|
2012-01-03 17:25:14 +00:00
|
|
|
rc = cap_capable(cred, ns, cap, audit);
|
2005-04-16 22:20:36 +00:00
|
|
|
if (rc)
|
|
|
|
return rc;
|
|
|
|
|
2012-01-03 17:25:14 +00:00
|
|
|
return cred_has_capability(cred, cap, audit);
|
2005-04-16 22:20:36 +00:00
|
|
|
}
|
|
|
|
|
|
|
|
static int selinux_quotactl(int cmds, int type, int id, struct super_block *sb)
|
|
|
|
{
|
2008-11-13 23:39:21 +00:00
|
|
|
const struct cred *cred = current_cred();
|
2005-04-16 22:20:36 +00:00
|
|
|
int rc = 0;
|
|
|
|
|
|
|
|
if (!sb)
|
|
|
|
return 0;
|
|
|
|
|
|
|
|
switch (cmds) {
|
2008-04-17 17:17:49 +00:00
|
|
|
case Q_SYNC:
|
|
|
|
case Q_QUOTAON:
|
|
|
|
case Q_QUOTAOFF:
|
|
|
|
case Q_SETINFO:
|
|
|
|
case Q_SETQUOTA:
|
2008-11-13 23:39:21 +00:00
|
|
|
rc = superblock_has_perm(cred, sb, FILESYSTEM__QUOTAMOD, NULL);
|
2008-04-17 17:17:49 +00:00
|
|
|
break;
|
|
|
|
case Q_GETFMT:
|
|
|
|
case Q_GETINFO:
|
|
|
|
case Q_GETQUOTA:
|
2008-11-13 23:39:21 +00:00
|
|
|
rc = superblock_has_perm(cred, sb, FILESYSTEM__QUOTAGET, NULL);
|
2008-04-17 17:17:49 +00:00
|
|
|
break;
|
|
|
|
default:
|
|
|
|
rc = 0; /* let the kernel handle invalid cmds */
|
|
|
|
break;
|
2005-04-16 22:20:36 +00:00
|
|
|
}
|
|
|
|
return rc;
|
|
|
|
}
|
|
|
|
|
|
|
|
static int selinux_quota_on(struct dentry *dentry)
|
|
|
|
{
|
2008-11-13 23:39:21 +00:00
|
|
|
const struct cred *cred = current_cred();
|
|
|
|
|
2011-04-28 20:04:24 +00:00
|
|
|
return dentry_has_perm(cred, dentry, FILE__QUOTAON);
|
2005-04-16 22:20:36 +00:00
|
|
|
}
|
|
|
|
|
2010-11-15 23:36:29 +00:00
|
|
|
static int selinux_syslog(int type)
|
2005-04-16 22:20:36 +00:00
|
|
|
{
|
|
|
|
int rc;
|
|
|
|
|
|
|
|
switch (type) {
|
2010-02-03 23:37:13 +00:00
|
|
|
case SYSLOG_ACTION_READ_ALL: /* Read last kernel messages */
|
|
|
|
case SYSLOG_ACTION_SIZE_BUFFER: /* Return size of the log buffer */
|
2008-04-17 17:17:49 +00:00
|
|
|
rc = task_has_system(current, SYSTEM__SYSLOG_READ);
|
|
|
|
break;
|
2010-02-03 23:37:13 +00:00
|
|
|
case SYSLOG_ACTION_CONSOLE_OFF: /* Disable logging to console */
|
|
|
|
case SYSLOG_ACTION_CONSOLE_ON: /* Enable logging to console */
|
|
|
|
/* Set level of messages printed to console */
|
|
|
|
case SYSLOG_ACTION_CONSOLE_LEVEL:
|
2008-04-17 17:17:49 +00:00
|
|
|
rc = task_has_system(current, SYSTEM__SYSLOG_CONSOLE);
|
|
|
|
break;
|
2010-02-03 23:37:13 +00:00
|
|
|
case SYSLOG_ACTION_CLOSE: /* Close log */
|
|
|
|
case SYSLOG_ACTION_OPEN: /* Open log */
|
|
|
|
case SYSLOG_ACTION_READ: /* Read from log */
|
|
|
|
case SYSLOG_ACTION_READ_CLEAR: /* Read/clear last kernel messages */
|
|
|
|
case SYSLOG_ACTION_CLEAR: /* Clear ring buffer */
|
2008-04-17 17:17:49 +00:00
|
|
|
default:
|
|
|
|
rc = task_has_system(current, SYSTEM__SYSLOG_MOD);
|
|
|
|
break;
|
2005-04-16 22:20:36 +00:00
|
|
|
}
|
|
|
|
return rc;
|
|
|
|
}
|
|
|
|
|
|
|
|
/*
|
|
|
|
* Check that a process has enough memory to allocate a new virtual
|
|
|
|
* mapping. 0 means there is enough memory for the allocation to
|
|
|
|
* succeed and -ENOMEM implies there is not.
|
|
|
|
*
|
|
|
|
* Do not audit the selinux permission check, as this is applied to all
|
|
|
|
* processes that allocate mappings.
|
|
|
|
*/
|
2007-08-22 21:01:28 +00:00
|
|
|
static int selinux_vm_enough_memory(struct mm_struct *mm, long pages)
|
2005-04-16 22:20:36 +00:00
|
|
|
{
|
|
|
|
int rc, cap_sys_admin = 0;
|
|
|
|
|
2012-01-03 17:25:14 +00:00
|
|
|
rc = selinux_capable(current_cred(), &init_user_ns, CAP_SYS_ADMIN,
|
CRED: Fix regression in cap_capable() as shown up by sys_faccessat() [ver #3]
Fix a regression in cap_capable() due to:
commit 3b11a1decef07c19443d24ae926982bc8ec9f4c0
Author: David Howells <dhowells@redhat.com>
Date: Fri Nov 14 10:39:26 2008 +1100
CRED: Differentiate objective and effective subjective credentials on a task
The problem is that the above patch allows a process to have two sets of
credentials, and for the most part uses the subjective credentials when
accessing current's creds.
There is, however, one exception: cap_capable(), and thus capable(), uses the
real/objective credentials of the target task, whether or not it is the current
task.
Ordinarily this doesn't matter, since usually the two cred pointers in current
point to the same set of creds. However, sys_faccessat() makes use of this
facility to override the credentials of the calling process to make its test,
without affecting the creds as seen from other processes.
One of the things sys_faccessat() does is to make an adjustment to the
effective capabilities mask, which cap_capable(), as it stands, then ignores.
The affected capability check is in generic_permission():
if (!(mask & MAY_EXEC) || execute_ok(inode))
if (capable(CAP_DAC_OVERRIDE))
return 0;
This change passes the set of credentials to be tested down into the commoncap
and SELinux code. The security functions called by capable() and
has_capability() select the appropriate set of credentials from the process
being checked.
This can be tested by compiling the following program from the XFS testsuite:
/*
* t_access_root.c - trivial test program to show permission bug.
*
* Written by Michael Kerrisk - copyright ownership not pursued.
* Sourced from: http://linux.derkeiler.com/Mailing-Lists/Kernel/2003-10/6030.html
*/
#include <limits.h>
#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>
#include <fcntl.h>
#include <sys/stat.h>
#define UID 500
#define GID 100
#define PERM 0
#define TESTPATH "/tmp/t_access"
static void
errExit(char *msg)
{
perror(msg);
exit(EXIT_FAILURE);
} /* errExit */
static void
accessTest(char *file, int mask, char *mstr)
{
printf("access(%s, %s) returns %d\n", file, mstr, access(file, mask));
} /* accessTest */
int
main(int argc, char *argv[])
{
int fd, perm, uid, gid;
char *testpath;
char cmd[PATH_MAX + 20];
testpath = (argc > 1) ? argv[1] : TESTPATH;
perm = (argc > 2) ? strtoul(argv[2], NULL, 8) : PERM;
uid = (argc > 3) ? atoi(argv[3]) : UID;
gid = (argc > 4) ? atoi(argv[4]) : GID;
unlink(testpath);
fd = open(testpath, O_RDWR | O_CREAT, 0);
if (fd == -1) errExit("open");
if (fchown(fd, uid, gid) == -1) errExit("fchown");
if (fchmod(fd, perm) == -1) errExit("fchmod");
close(fd);
snprintf(cmd, sizeof(cmd), "ls -l %s", testpath);
system(cmd);
if (seteuid(uid) == -1) errExit("seteuid");
accessTest(testpath, 0, "0");
accessTest(testpath, R_OK, "R_OK");
accessTest(testpath, W_OK, "W_OK");
accessTest(testpath, X_OK, "X_OK");
accessTest(testpath, R_OK | W_OK, "R_OK | W_OK");
accessTest(testpath, R_OK | X_OK, "R_OK | X_OK");
accessTest(testpath, W_OK | X_OK, "W_OK | X_OK");
accessTest(testpath, R_OK | W_OK | X_OK, "R_OK | W_OK | X_OK");
exit(EXIT_SUCCESS);
} /* main */
This can be run against an Ext3 filesystem as well as against an XFS
filesystem. If successful, it will show:
[root@andromeda src]# ./t_access_root /tmp/xxx 0 4043 4043
---------- 1 dhowells dhowells 0 2008-12-31 03:00 /tmp/xxx
access(/tmp/xxx, 0) returns 0
access(/tmp/xxx, R_OK) returns 0
access(/tmp/xxx, W_OK) returns 0
access(/tmp/xxx, X_OK) returns -1
access(/tmp/xxx, R_OK | W_OK) returns 0
access(/tmp/xxx, R_OK | X_OK) returns -1
access(/tmp/xxx, W_OK | X_OK) returns -1
access(/tmp/xxx, R_OK | W_OK | X_OK) returns -1
If unsuccessful, it will show:
[root@andromeda src]# ./t_access_root /tmp/xxx 0 4043 4043
---------- 1 dhowells dhowells 0 2008-12-31 02:56 /tmp/xxx
access(/tmp/xxx, 0) returns 0
access(/tmp/xxx, R_OK) returns -1
access(/tmp/xxx, W_OK) returns -1
access(/tmp/xxx, X_OK) returns -1
access(/tmp/xxx, R_OK | W_OK) returns -1
access(/tmp/xxx, R_OK | X_OK) returns -1
access(/tmp/xxx, W_OK | X_OK) returns -1
access(/tmp/xxx, R_OK | W_OK | X_OK) returns -1
I've also tested the fix with the SELinux and syscalls LTP testsuites.
Signed-off-by: David Howells <dhowells@redhat.com>
Tested-by: J. Bruce Fields <bfields@citi.umich.edu>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Signed-off-by: James Morris <jmorris@namei.org>
2009-01-06 22:27:01 +00:00
|
|
|
SECURITY_CAP_NOAUDIT);
|
2005-04-16 22:20:36 +00:00
|
|
|
if (rc == 0)
|
|
|
|
cap_sys_admin = 1;
|
|
|
|
|
2007-08-22 21:01:28 +00:00
|
|
|
return __vm_enough_memory(mm, pages, cap_sys_admin);
|
2005-04-16 22:20:36 +00:00
|
|
|
}
|
|
|
|
|
|
|
|
/* binprm security operations */
|
|
|
|
|
CRED: Make execve() take advantage of copy-on-write credentials
Make execve() take advantage of copy-on-write credentials, allowing it to set
up the credentials in advance, and then commit the whole lot after the point
of no return.
This patch and the preceding patches have been tested with the LTP SELinux
testsuite.
This patch makes several logical sets of alteration:
(1) execve().
The credential bits from struct linux_binprm are, for the most part,
replaced with a single credentials pointer (bprm->cred). This means that
all the creds can be calculated in advance and then applied at the point
of no return with no possibility of failure.
I would like to replace bprm->cap_effective with:
cap_isclear(bprm->cap_effective)
but this seems impossible due to special behaviour for processes of pid 1
(they always retain their parent's capability masks where normally they'd
be changed - see cap_bprm_set_creds()).
The following sequence of events now happens:
(a) At the start of do_execve, the current task's cred_exec_mutex is
locked to prevent PTRACE_ATTACH from obsoleting the calculation of
creds that we make.
(a) prepare_exec_creds() is then called to make a copy of the current
task's credentials and prepare it. This copy is then assigned to
bprm->cred.
This renders security_bprm_alloc() and security_bprm_free()
unnecessary, and so they've been removed.
(b) The determination of unsafe execution is now performed immediately
after (a) rather than later on in the code. The result is stored in
bprm->unsafe for future reference.
(c) prepare_binprm() is called, possibly multiple times.
(i) This applies the result of set[ug]id binaries to the new creds
attached to bprm->cred. Personality bit clearance is recorded,
but now deferred on the basis that the exec procedure may yet
fail.
(ii) This then calls the new security_bprm_set_creds(). This should
calculate the new LSM and capability credentials into *bprm->cred.
This folds together security_bprm_set() and parts of
security_bprm_apply_creds() (these two have been removed).
Anything that might fail must be done at this point.
(iii) bprm->cred_prepared is set to 1.
bprm->cred_prepared is 0 on the first pass of the security
calculations, and 1 on all subsequent passes. This allows SELinux
in (ii) to base its calculations only on the initial script and
not on the interpreter.
(d) flush_old_exec() is called to commit the task to execution. This
performs the following steps with regard to credentials:
(i) Clear pdeath_signal and set dumpable on certain circumstances that
may not be covered by commit_creds().
(ii) Clear any bits in current->personality that were deferred from
(c.i).
(e) install_exec_creds() [compute_creds() as was] is called to install the
new credentials. This performs the following steps with regard to
credentials:
(i) Calls security_bprm_committing_creds() to apply any security
requirements, such as flushing unauthorised files in SELinux, that
must be done before the credentials are changed.
This is made up of bits of security_bprm_apply_creds() and
security_bprm_post_apply_creds(), both of which have been removed.
This function is not allowed to fail; anything that might fail
must have been done in (c.ii).
(ii) Calls commit_creds() to apply the new credentials in a single
assignment (more or less). Possibly pdeath_signal and dumpable
should be part of struct creds.
(iii) Unlocks the task's cred_replace_mutex, thus allowing
PTRACE_ATTACH to take place.
(iv) Clears The bprm->cred pointer as the credentials it was holding
are now immutable.
(v) Calls security_bprm_committed_creds() to apply any security
alterations that must be done after the creds have been changed.
SELinux uses this to flush signals and signal handlers.
(f) If an error occurs before (d.i), bprm_free() will call abort_creds()
to destroy the proposed new credentials and will then unlock
cred_replace_mutex. No changes to the credentials will have been
made.
(2) LSM interface.
A number of functions have been changed, added or removed:
(*) security_bprm_alloc(), ->bprm_alloc_security()
(*) security_bprm_free(), ->bprm_free_security()
Removed in favour of preparing new credentials and modifying those.
(*) security_bprm_apply_creds(), ->bprm_apply_creds()
(*) security_bprm_post_apply_creds(), ->bprm_post_apply_creds()
Removed; split between security_bprm_set_creds(),
security_bprm_committing_creds() and security_bprm_committed_creds().
(*) security_bprm_set(), ->bprm_set_security()
Removed; folded into security_bprm_set_creds().
(*) security_bprm_set_creds(), ->bprm_set_creds()
New. The new credentials in bprm->creds should be checked and set up
as appropriate. bprm->cred_prepared is 0 on the first call, 1 on the
second and subsequent calls.
(*) security_bprm_committing_creds(), ->bprm_committing_creds()
(*) security_bprm_committed_creds(), ->bprm_committed_creds()
New. Apply the security effects of the new credentials. This
includes closing unauthorised files in SELinux. This function may not
fail. When the former is called, the creds haven't yet been applied
to the process; when the latter is called, they have.
The former may access bprm->cred, the latter may not.
(3) SELinux.
SELinux has a number of changes, in addition to those to support the LSM
interface changes mentioned above:
(a) The bprm_security_struct struct has been removed in favour of using
the credentials-under-construction approach.
(c) flush_unauthorized_files() now takes a cred pointer and passes it on
to inode_has_perm(), file_has_perm() and dentry_open().
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: James Morris <jmorris@namei.org>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Signed-off-by: James Morris <jmorris@namei.org>
2008-11-13 23:39:24 +00:00
|
|
|
static int selinux_bprm_set_creds(struct linux_binprm *bprm)
|
2005-04-16 22:20:36 +00:00
|
|
|
{
|
CRED: Make execve() take advantage of copy-on-write credentials
Make execve() take advantage of copy-on-write credentials, allowing it to set
up the credentials in advance, and then commit the whole lot after the point
of no return.
This patch and the preceding patches have been tested with the LTP SELinux
testsuite.
This patch makes several logical sets of alteration:
(1) execve().
The credential bits from struct linux_binprm are, for the most part,
replaced with a single credentials pointer (bprm->cred). This means that
all the creds can be calculated in advance and then applied at the point
of no return with no possibility of failure.
I would like to replace bprm->cap_effective with:
cap_isclear(bprm->cap_effective)
but this seems impossible due to special behaviour for processes of pid 1
(they always retain their parent's capability masks where normally they'd
be changed - see cap_bprm_set_creds()).
The following sequence of events now happens:
(a) At the start of do_execve, the current task's cred_exec_mutex is
locked to prevent PTRACE_ATTACH from obsoleting the calculation of
creds that we make.
(a) prepare_exec_creds() is then called to make a copy of the current
task's credentials and prepare it. This copy is then assigned to
bprm->cred.
This renders security_bprm_alloc() and security_bprm_free()
unnecessary, and so they've been removed.
(b) The determination of unsafe execution is now performed immediately
after (a) rather than later on in the code. The result is stored in
bprm->unsafe for future reference.
(c) prepare_binprm() is called, possibly multiple times.
(i) This applies the result of set[ug]id binaries to the new creds
attached to bprm->cred. Personality bit clearance is recorded,
but now deferred on the basis that the exec procedure may yet
fail.
(ii) This then calls the new security_bprm_set_creds(). This should
calculate the new LSM and capability credentials into *bprm->cred.
This folds together security_bprm_set() and parts of
security_bprm_apply_creds() (these two have been removed).
Anything that might fail must be done at this point.
(iii) bprm->cred_prepared is set to 1.
bprm->cred_prepared is 0 on the first pass of the security
calculations, and 1 on all subsequent passes. This allows SELinux
in (ii) to base its calculations only on the initial script and
not on the interpreter.
(d) flush_old_exec() is called to commit the task to execution. This
performs the following steps with regard to credentials:
(i) Clear pdeath_signal and set dumpable on certain circumstances that
may not be covered by commit_creds().
(ii) Clear any bits in current->personality that were deferred from
(c.i).
(e) install_exec_creds() [compute_creds() as was] is called to install the
new credentials. This performs the following steps with regard to
credentials:
(i) Calls security_bprm_committing_creds() to apply any security
requirements, such as flushing unauthorised files in SELinux, that
must be done before the credentials are changed.
This is made up of bits of security_bprm_apply_creds() and
security_bprm_post_apply_creds(), both of which have been removed.
This function is not allowed to fail; anything that might fail
must have been done in (c.ii).
(ii) Calls commit_creds() to apply the new credentials in a single
assignment (more or less). Possibly pdeath_signal and dumpable
should be part of struct creds.
(iii) Unlocks the task's cred_replace_mutex, thus allowing
PTRACE_ATTACH to take place.
(iv) Clears The bprm->cred pointer as the credentials it was holding
are now immutable.
(v) Calls security_bprm_committed_creds() to apply any security
alterations that must be done after the creds have been changed.
SELinux uses this to flush signals and signal handlers.
(f) If an error occurs before (d.i), bprm_free() will call abort_creds()
to destroy the proposed new credentials and will then unlock
cred_replace_mutex. No changes to the credentials will have been
made.
(2) LSM interface.
A number of functions have been changed, added or removed:
(*) security_bprm_alloc(), ->bprm_alloc_security()
(*) security_bprm_free(), ->bprm_free_security()
Removed in favour of preparing new credentials and modifying those.
(*) security_bprm_apply_creds(), ->bprm_apply_creds()
(*) security_bprm_post_apply_creds(), ->bprm_post_apply_creds()
Removed; split between security_bprm_set_creds(),
security_bprm_committing_creds() and security_bprm_committed_creds().
(*) security_bprm_set(), ->bprm_set_security()
Removed; folded into security_bprm_set_creds().
(*) security_bprm_set_creds(), ->bprm_set_creds()
New. The new credentials in bprm->creds should be checked and set up
as appropriate. bprm->cred_prepared is 0 on the first call, 1 on the
second and subsequent calls.
(*) security_bprm_committing_creds(), ->bprm_committing_creds()
(*) security_bprm_committed_creds(), ->bprm_committed_creds()
New. Apply the security effects of the new credentials. This
includes closing unauthorised files in SELinux. This function may not
fail. When the former is called, the creds haven't yet been applied
to the process; when the latter is called, they have.
The former may access bprm->cred, the latter may not.
(3) SELinux.
SELinux has a number of changes, in addition to those to support the LSM
interface changes mentioned above:
(a) The bprm_security_struct struct has been removed in favour of using
the credentials-under-construction approach.
(c) flush_unauthorized_files() now takes a cred pointer and passes it on
to inode_has_perm(), file_has_perm() and dentry_open().
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: James Morris <jmorris@namei.org>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Signed-off-by: James Morris <jmorris@namei.org>
2008-11-13 23:39:24 +00:00
|
|
|
const struct task_security_struct *old_tsec;
|
|
|
|
struct task_security_struct *new_tsec;
|
2005-04-16 22:20:36 +00:00
|
|
|
struct inode_security_struct *isec;
|
2009-07-14 16:14:09 +00:00
|
|
|
struct common_audit_data ad;
|
2013-01-23 22:07:38 +00:00
|
|
|
struct inode *inode = file_inode(bprm->file);
|
2005-04-16 22:20:36 +00:00
|
|
|
int rc;
|
|
|
|
|
2009-02-12 20:01:04 +00:00
|
|
|
rc = cap_bprm_set_creds(bprm);
|
2005-04-16 22:20:36 +00:00
|
|
|
if (rc)
|
|
|
|
return rc;
|
|
|
|
|
CRED: Make execve() take advantage of copy-on-write credentials
Make execve() take advantage of copy-on-write credentials, allowing it to set
up the credentials in advance, and then commit the whole lot after the point
of no return.
This patch and the preceding patches have been tested with the LTP SELinux
testsuite.
This patch makes several logical sets of alteration:
(1) execve().
The credential bits from struct linux_binprm are, for the most part,
replaced with a single credentials pointer (bprm->cred). This means that
all the creds can be calculated in advance and then applied at the point
of no return with no possibility of failure.
I would like to replace bprm->cap_effective with:
cap_isclear(bprm->cap_effective)
but this seems impossible due to special behaviour for processes of pid 1
(they always retain their parent's capability masks where normally they'd
be changed - see cap_bprm_set_creds()).
The following sequence of events now happens:
(a) At the start of do_execve, the current task's cred_exec_mutex is
locked to prevent PTRACE_ATTACH from obsoleting the calculation of
creds that we make.
(a) prepare_exec_creds() is then called to make a copy of the current
task's credentials and prepare it. This copy is then assigned to
bprm->cred.
This renders security_bprm_alloc() and security_bprm_free()
unnecessary, and so they've been removed.
(b) The determination of unsafe execution is now performed immediately
after (a) rather than later on in the code. The result is stored in
bprm->unsafe for future reference.
(c) prepare_binprm() is called, possibly multiple times.
(i) This applies the result of set[ug]id binaries to the new creds
attached to bprm->cred. Personality bit clearance is recorded,
but now deferred on the basis that the exec procedure may yet
fail.
(ii) This then calls the new security_bprm_set_creds(). This should
calculate the new LSM and capability credentials into *bprm->cred.
This folds together security_bprm_set() and parts of
security_bprm_apply_creds() (these two have been removed).
Anything that might fail must be done at this point.
(iii) bprm->cred_prepared is set to 1.
bprm->cred_prepared is 0 on the first pass of the security
calculations, and 1 on all subsequent passes. This allows SELinux
in (ii) to base its calculations only on the initial script and
not on the interpreter.
(d) flush_old_exec() is called to commit the task to execution. This
performs the following steps with regard to credentials:
(i) Clear pdeath_signal and set dumpable on certain circumstances that
may not be covered by commit_creds().
(ii) Clear any bits in current->personality that were deferred from
(c.i).
(e) install_exec_creds() [compute_creds() as was] is called to install the
new credentials. This performs the following steps with regard to
credentials:
(i) Calls security_bprm_committing_creds() to apply any security
requirements, such as flushing unauthorised files in SELinux, that
must be done before the credentials are changed.
This is made up of bits of security_bprm_apply_creds() and
security_bprm_post_apply_creds(), both of which have been removed.
This function is not allowed to fail; anything that might fail
must have been done in (c.ii).
(ii) Calls commit_creds() to apply the new credentials in a single
assignment (more or less). Possibly pdeath_signal and dumpable
should be part of struct creds.
(iii) Unlocks the task's cred_replace_mutex, thus allowing
PTRACE_ATTACH to take place.
(iv) Clears The bprm->cred pointer as the credentials it was holding
are now immutable.
(v) Calls security_bprm_committed_creds() to apply any security
alterations that must be done after the creds have been changed.
SELinux uses this to flush signals and signal handlers.
(f) If an error occurs before (d.i), bprm_free() will call abort_creds()
to destroy the proposed new credentials and will then unlock
cred_replace_mutex. No changes to the credentials will have been
made.
(2) LSM interface.
A number of functions have been changed, added or removed:
(*) security_bprm_alloc(), ->bprm_alloc_security()
(*) security_bprm_free(), ->bprm_free_security()
Removed in favour of preparing new credentials and modifying those.
(*) security_bprm_apply_creds(), ->bprm_apply_creds()
(*) security_bprm_post_apply_creds(), ->bprm_post_apply_creds()
Removed; split between security_bprm_set_creds(),
security_bprm_committing_creds() and security_bprm_committed_creds().
(*) security_bprm_set(), ->bprm_set_security()
Removed; folded into security_bprm_set_creds().
(*) security_bprm_set_creds(), ->bprm_set_creds()
New. The new credentials in bprm->creds should be checked and set up
as appropriate. bprm->cred_prepared is 0 on the first call, 1 on the
second and subsequent calls.
(*) security_bprm_committing_creds(), ->bprm_committing_creds()
(*) security_bprm_committed_creds(), ->bprm_committed_creds()
New. Apply the security effects of the new credentials. This
includes closing unauthorised files in SELinux. This function may not
fail. When the former is called, the creds haven't yet been applied
to the process; when the latter is called, they have.
The former may access bprm->cred, the latter may not.
(3) SELinux.
SELinux has a number of changes, in addition to those to support the LSM
interface changes mentioned above:
(a) The bprm_security_struct struct has been removed in favour of using
the credentials-under-construction approach.
(c) flush_unauthorized_files() now takes a cred pointer and passes it on
to inode_has_perm(), file_has_perm() and dentry_open().
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: James Morris <jmorris@namei.org>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Signed-off-by: James Morris <jmorris@namei.org>
2008-11-13 23:39:24 +00:00
|
|
|
/* SELinux context only depends on initial program or script and not
|
|
|
|
* the script interpreter */
|
|
|
|
if (bprm->cred_prepared)
|
2005-04-16 22:20:36 +00:00
|
|
|
return 0;
|
|
|
|
|
CRED: Make execve() take advantage of copy-on-write credentials
Make execve() take advantage of copy-on-write credentials, allowing it to set
up the credentials in advance, and then commit the whole lot after the point
of no return.
This patch and the preceding patches have been tested with the LTP SELinux
testsuite.
This patch makes several logical sets of alteration:
(1) execve().
The credential bits from struct linux_binprm are, for the most part,
replaced with a single credentials pointer (bprm->cred). This means that
all the creds can be calculated in advance and then applied at the point
of no return with no possibility of failure.
I would like to replace bprm->cap_effective with:
cap_isclear(bprm->cap_effective)
but this seems impossible due to special behaviour for processes of pid 1
(they always retain their parent's capability masks where normally they'd
be changed - see cap_bprm_set_creds()).
The following sequence of events now happens:
(a) At the start of do_execve, the current task's cred_exec_mutex is
locked to prevent PTRACE_ATTACH from obsoleting the calculation of
creds that we make.
(a) prepare_exec_creds() is then called to make a copy of the current
task's credentials and prepare it. This copy is then assigned to
bprm->cred.
This renders security_bprm_alloc() and security_bprm_free()
unnecessary, and so they've been removed.
(b) The determination of unsafe execution is now performed immediately
after (a) rather than later on in the code. The result is stored in
bprm->unsafe for future reference.
(c) prepare_binprm() is called, possibly multiple times.
(i) This applies the result of set[ug]id binaries to the new creds
attached to bprm->cred. Personality bit clearance is recorded,
but now deferred on the basis that the exec procedure may yet
fail.
(ii) This then calls the new security_bprm_set_creds(). This should
calculate the new LSM and capability credentials into *bprm->cred.
This folds together security_bprm_set() and parts of
security_bprm_apply_creds() (these two have been removed).
Anything that might fail must be done at this point.
(iii) bprm->cred_prepared is set to 1.
bprm->cred_prepared is 0 on the first pass of the security
calculations, and 1 on all subsequent passes. This allows SELinux
in (ii) to base its calculations only on the initial script and
not on the interpreter.
(d) flush_old_exec() is called to commit the task to execution. This
performs the following steps with regard to credentials:
(i) Clear pdeath_signal and set dumpable on certain circumstances that
may not be covered by commit_creds().
(ii) Clear any bits in current->personality that were deferred from
(c.i).
(e) install_exec_creds() [compute_creds() as was] is called to install the
new credentials. This performs the following steps with regard to
credentials:
(i) Calls security_bprm_committing_creds() to apply any security
requirements, such as flushing unauthorised files in SELinux, that
must be done before the credentials are changed.
This is made up of bits of security_bprm_apply_creds() and
security_bprm_post_apply_creds(), both of which have been removed.
This function is not allowed to fail; anything that might fail
must have been done in (c.ii).
(ii) Calls commit_creds() to apply the new credentials in a single
assignment (more or less). Possibly pdeath_signal and dumpable
should be part of struct creds.
(iii) Unlocks the task's cred_replace_mutex, thus allowing
PTRACE_ATTACH to take place.
(iv) Clears The bprm->cred pointer as the credentials it was holding
are now immutable.
(v) Calls security_bprm_committed_creds() to apply any security
alterations that must be done after the creds have been changed.
SELinux uses this to flush signals and signal handlers.
(f) If an error occurs before (d.i), bprm_free() will call abort_creds()
to destroy the proposed new credentials and will then unlock
cred_replace_mutex. No changes to the credentials will have been
made.
(2) LSM interface.
A number of functions have been changed, added or removed:
(*) security_bprm_alloc(), ->bprm_alloc_security()
(*) security_bprm_free(), ->bprm_free_security()
Removed in favour of preparing new credentials and modifying those.
(*) security_bprm_apply_creds(), ->bprm_apply_creds()
(*) security_bprm_post_apply_creds(), ->bprm_post_apply_creds()
Removed; split between security_bprm_set_creds(),
security_bprm_committing_creds() and security_bprm_committed_creds().
(*) security_bprm_set(), ->bprm_set_security()
Removed; folded into security_bprm_set_creds().
(*) security_bprm_set_creds(), ->bprm_set_creds()
New. The new credentials in bprm->creds should be checked and set up
as appropriate. bprm->cred_prepared is 0 on the first call, 1 on the
second and subsequent calls.
(*) security_bprm_committing_creds(), ->bprm_committing_creds()
(*) security_bprm_committed_creds(), ->bprm_committed_creds()
New. Apply the security effects of the new credentials. This
includes closing unauthorised files in SELinux. This function may not
fail. When the former is called, the creds haven't yet been applied
to the process; when the latter is called, they have.
The former may access bprm->cred, the latter may not.
(3) SELinux.
SELinux has a number of changes, in addition to those to support the LSM
interface changes mentioned above:
(a) The bprm_security_struct struct has been removed in favour of using
the credentials-under-construction approach.
(c) flush_unauthorized_files() now takes a cred pointer and passes it on
to inode_has_perm(), file_has_perm() and dentry_open().
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: James Morris <jmorris@namei.org>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Signed-off-by: James Morris <jmorris@namei.org>
2008-11-13 23:39:24 +00:00
|
|
|
old_tsec = current_security();
|
|
|
|
new_tsec = bprm->cred->security;
|
2005-04-16 22:20:36 +00:00
|
|
|
isec = inode->i_security;
|
|
|
|
|
|
|
|
/* Default to the current task SID. */
|
CRED: Make execve() take advantage of copy-on-write credentials
Make execve() take advantage of copy-on-write credentials, allowing it to set
up the credentials in advance, and then commit the whole lot after the point
of no return.
This patch and the preceding patches have been tested with the LTP SELinux
testsuite.
This patch makes several logical sets of alteration:
(1) execve().
The credential bits from struct linux_binprm are, for the most part,
replaced with a single credentials pointer (bprm->cred). This means that
all the creds can be calculated in advance and then applied at the point
of no return with no possibility of failure.
I would like to replace bprm->cap_effective with:
cap_isclear(bprm->cap_effective)
but this seems impossible due to special behaviour for processes of pid 1
(they always retain their parent's capability masks where normally they'd
be changed - see cap_bprm_set_creds()).
The following sequence of events now happens:
(a) At the start of do_execve, the current task's cred_exec_mutex is
locked to prevent PTRACE_ATTACH from obsoleting the calculation of
creds that we make.
(a) prepare_exec_creds() is then called to make a copy of the current
task's credentials and prepare it. This copy is then assigned to
bprm->cred.
This renders security_bprm_alloc() and security_bprm_free()
unnecessary, and so they've been removed.
(b) The determination of unsafe execution is now performed immediately
after (a) rather than later on in the code. The result is stored in
bprm->unsafe for future reference.
(c) prepare_binprm() is called, possibly multiple times.
(i) This applies the result of set[ug]id binaries to the new creds
attached to bprm->cred. Personality bit clearance is recorded,
but now deferred on the basis that the exec procedure may yet
fail.
(ii) This then calls the new security_bprm_set_creds(). This should
calculate the new LSM and capability credentials into *bprm->cred.
This folds together security_bprm_set() and parts of
security_bprm_apply_creds() (these two have been removed).
Anything that might fail must be done at this point.
(iii) bprm->cred_prepared is set to 1.
bprm->cred_prepared is 0 on the first pass of the security
calculations, and 1 on all subsequent passes. This allows SELinux
in (ii) to base its calculations only on the initial script and
not on the interpreter.
(d) flush_old_exec() is called to commit the task to execution. This
performs the following steps with regard to credentials:
(i) Clear pdeath_signal and set dumpable on certain circumstances that
may not be covered by commit_creds().
(ii) Clear any bits in current->personality that were deferred from
(c.i).
(e) install_exec_creds() [compute_creds() as was] is called to install the
new credentials. This performs the following steps with regard to
credentials:
(i) Calls security_bprm_committing_creds() to apply any security
requirements, such as flushing unauthorised files in SELinux, that
must be done before the credentials are changed.
This is made up of bits of security_bprm_apply_creds() and
security_bprm_post_apply_creds(), both of which have been removed.
This function is not allowed to fail; anything that might fail
must have been done in (c.ii).
(ii) Calls commit_creds() to apply the new credentials in a single
assignment (more or less). Possibly pdeath_signal and dumpable
should be part of struct creds.
(iii) Unlocks the task's cred_replace_mutex, thus allowing
PTRACE_ATTACH to take place.
(iv) Clears The bprm->cred pointer as the credentials it was holding
are now immutable.
(v) Calls security_bprm_committed_creds() to apply any security
alterations that must be done after the creds have been changed.
SELinux uses this to flush signals and signal handlers.
(f) If an error occurs before (d.i), bprm_free() will call abort_creds()
to destroy the proposed new credentials and will then unlock
cred_replace_mutex. No changes to the credentials will have been
made.
(2) LSM interface.
A number of functions have been changed, added or removed:
(*) security_bprm_alloc(), ->bprm_alloc_security()
(*) security_bprm_free(), ->bprm_free_security()
Removed in favour of preparing new credentials and modifying those.
(*) security_bprm_apply_creds(), ->bprm_apply_creds()
(*) security_bprm_post_apply_creds(), ->bprm_post_apply_creds()
Removed; split between security_bprm_set_creds(),
security_bprm_committing_creds() and security_bprm_committed_creds().
(*) security_bprm_set(), ->bprm_set_security()
Removed; folded into security_bprm_set_creds().
(*) security_bprm_set_creds(), ->bprm_set_creds()
New. The new credentials in bprm->creds should be checked and set up
as appropriate. bprm->cred_prepared is 0 on the first call, 1 on the
second and subsequent calls.
(*) security_bprm_committing_creds(), ->bprm_committing_creds()
(*) security_bprm_committed_creds(), ->bprm_committed_creds()
New. Apply the security effects of the new credentials. This
includes closing unauthorised files in SELinux. This function may not
fail. When the former is called, the creds haven't yet been applied
to the process; when the latter is called, they have.
The former may access bprm->cred, the latter may not.
(3) SELinux.
SELinux has a number of changes, in addition to those to support the LSM
interface changes mentioned above:
(a) The bprm_security_struct struct has been removed in favour of using
the credentials-under-construction approach.
(c) flush_unauthorized_files() now takes a cred pointer and passes it on
to inode_has_perm(), file_has_perm() and dentry_open().
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: James Morris <jmorris@namei.org>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Signed-off-by: James Morris <jmorris@namei.org>
2008-11-13 23:39:24 +00:00
|
|
|
new_tsec->sid = old_tsec->sid;
|
|
|
|
new_tsec->osid = old_tsec->sid;
|
2005-04-16 22:20:36 +00:00
|
|
|
|
2006-06-27 09:53:42 +00:00
|
|
|
/* Reset fs, key, and sock SIDs on execve. */
|
CRED: Make execve() take advantage of copy-on-write credentials
Make execve() take advantage of copy-on-write credentials, allowing it to set
up the credentials in advance, and then commit the whole lot after the point
of no return.
This patch and the preceding patches have been tested with the LTP SELinux
testsuite.
This patch makes several logical sets of alteration:
(1) execve().
The credential bits from struct linux_binprm are, for the most part,
replaced with a single credentials pointer (bprm->cred). This means that
all the creds can be calculated in advance and then applied at the point
of no return with no possibility of failure.
I would like to replace bprm->cap_effective with:
cap_isclear(bprm->cap_effective)
but this seems impossible due to special behaviour for processes of pid 1
(they always retain their parent's capability masks where normally they'd
be changed - see cap_bprm_set_creds()).
The following sequence of events now happens:
(a) At the start of do_execve, the current task's cred_exec_mutex is
locked to prevent PTRACE_ATTACH from obsoleting the calculation of
creds that we make.
(a) prepare_exec_creds() is then called to make a copy of the current
task's credentials and prepare it. This copy is then assigned to
bprm->cred.
This renders security_bprm_alloc() and security_bprm_free()
unnecessary, and so they've been removed.
(b) The determination of unsafe execution is now performed immediately
after (a) rather than later on in the code. The result is stored in
bprm->unsafe for future reference.
(c) prepare_binprm() is called, possibly multiple times.
(i) This applies the result of set[ug]id binaries to the new creds
attached to bprm->cred. Personality bit clearance is recorded,
but now deferred on the basis that the exec procedure may yet
fail.
(ii) This then calls the new security_bprm_set_creds(). This should
calculate the new LSM and capability credentials into *bprm->cred.
This folds together security_bprm_set() and parts of
security_bprm_apply_creds() (these two have been removed).
Anything that might fail must be done at this point.
(iii) bprm->cred_prepared is set to 1.
bprm->cred_prepared is 0 on the first pass of the security
calculations, and 1 on all subsequent passes. This allows SELinux
in (ii) to base its calculations only on the initial script and
not on the interpreter.
(d) flush_old_exec() is called to commit the task to execution. This
performs the following steps with regard to credentials:
(i) Clear pdeath_signal and set dumpable on certain circumstances that
may not be covered by commit_creds().
(ii) Clear any bits in current->personality that were deferred from
(c.i).
(e) install_exec_creds() [compute_creds() as was] is called to install the
new credentials. This performs the following steps with regard to
credentials:
(i) Calls security_bprm_committing_creds() to apply any security
requirements, such as flushing unauthorised files in SELinux, that
must be done before the credentials are changed.
This is made up of bits of security_bprm_apply_creds() and
security_bprm_post_apply_creds(), both of which have been removed.
This function is not allowed to fail; anything that might fail
must have been done in (c.ii).
(ii) Calls commit_creds() to apply the new credentials in a single
assignment (more or less). Possibly pdeath_signal and dumpable
should be part of struct creds.
(iii) Unlocks the task's cred_replace_mutex, thus allowing
PTRACE_ATTACH to take place.
(iv) Clears The bprm->cred pointer as the credentials it was holding
are now immutable.
(v) Calls security_bprm_committed_creds() to apply any security
alterations that must be done after the creds have been changed.
SELinux uses this to flush signals and signal handlers.
(f) If an error occurs before (d.i), bprm_free() will call abort_creds()
to destroy the proposed new credentials and will then unlock
cred_replace_mutex. No changes to the credentials will have been
made.
(2) LSM interface.
A number of functions have been changed, added or removed:
(*) security_bprm_alloc(), ->bprm_alloc_security()
(*) security_bprm_free(), ->bprm_free_security()
Removed in favour of preparing new credentials and modifying those.
(*) security_bprm_apply_creds(), ->bprm_apply_creds()
(*) security_bprm_post_apply_creds(), ->bprm_post_apply_creds()
Removed; split between security_bprm_set_creds(),
security_bprm_committing_creds() and security_bprm_committed_creds().
(*) security_bprm_set(), ->bprm_set_security()
Removed; folded into security_bprm_set_creds().
(*) security_bprm_set_creds(), ->bprm_set_creds()
New. The new credentials in bprm->creds should be checked and set up
as appropriate. bprm->cred_prepared is 0 on the first call, 1 on the
second and subsequent calls.
(*) security_bprm_committing_creds(), ->bprm_committing_creds()
(*) security_bprm_committed_creds(), ->bprm_committed_creds()
New. Apply the security effects of the new credentials. This
includes closing unauthorised files in SELinux. This function may not
fail. When the former is called, the creds haven't yet been applied
to the process; when the latter is called, they have.
The former may access bprm->cred, the latter may not.
(3) SELinux.
SELinux has a number of changes, in addition to those to support the LSM
interface changes mentioned above:
(a) The bprm_security_struct struct has been removed in favour of using
the credentials-under-construction approach.
(c) flush_unauthorized_files() now takes a cred pointer and passes it on
to inode_has_perm(), file_has_perm() and dentry_open().
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: James Morris <jmorris@namei.org>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Signed-off-by: James Morris <jmorris@namei.org>
2008-11-13 23:39:24 +00:00
|
|
|
new_tsec->create_sid = 0;
|
|
|
|
new_tsec->keycreate_sid = 0;
|
|
|
|
new_tsec->sockcreate_sid = 0;
|
2005-04-16 22:20:36 +00:00
|
|
|
|
CRED: Make execve() take advantage of copy-on-write credentials
Make execve() take advantage of copy-on-write credentials, allowing it to set
up the credentials in advance, and then commit the whole lot after the point
of no return.
This patch and the preceding patches have been tested with the LTP SELinux
testsuite.
This patch makes several logical sets of alteration:
(1) execve().
The credential bits from struct linux_binprm are, for the most part,
replaced with a single credentials pointer (bprm->cred). This means that
all the creds can be calculated in advance and then applied at the point
of no return with no possibility of failure.
I would like to replace bprm->cap_effective with:
cap_isclear(bprm->cap_effective)
but this seems impossible due to special behaviour for processes of pid 1
(they always retain their parent's capability masks where normally they'd
be changed - see cap_bprm_set_creds()).
The following sequence of events now happens:
(a) At the start of do_execve, the current task's cred_exec_mutex is
locked to prevent PTRACE_ATTACH from obsoleting the calculation of
creds that we make.
(a) prepare_exec_creds() is then called to make a copy of the current
task's credentials and prepare it. This copy is then assigned to
bprm->cred.
This renders security_bprm_alloc() and security_bprm_free()
unnecessary, and so they've been removed.
(b) The determination of unsafe execution is now performed immediately
after (a) rather than later on in the code. The result is stored in
bprm->unsafe for future reference.
(c) prepare_binprm() is called, possibly multiple times.
(i) This applies the result of set[ug]id binaries to the new creds
attached to bprm->cred. Personality bit clearance is recorded,
but now deferred on the basis that the exec procedure may yet
fail.
(ii) This then calls the new security_bprm_set_creds(). This should
calculate the new LSM and capability credentials into *bprm->cred.
This folds together security_bprm_set() and parts of
security_bprm_apply_creds() (these two have been removed).
Anything that might fail must be done at this point.
(iii) bprm->cred_prepared is set to 1.
bprm->cred_prepared is 0 on the first pass of the security
calculations, and 1 on all subsequent passes. This allows SELinux
in (ii) to base its calculations only on the initial script and
not on the interpreter.
(d) flush_old_exec() is called to commit the task to execution. This
performs the following steps with regard to credentials:
(i) Clear pdeath_signal and set dumpable on certain circumstances that
may not be covered by commit_creds().
(ii) Clear any bits in current->personality that were deferred from
(c.i).
(e) install_exec_creds() [compute_creds() as was] is called to install the
new credentials. This performs the following steps with regard to
credentials:
(i) Calls security_bprm_committing_creds() to apply any security
requirements, such as flushing unauthorised files in SELinux, that
must be done before the credentials are changed.
This is made up of bits of security_bprm_apply_creds() and
security_bprm_post_apply_creds(), both of which have been removed.
This function is not allowed to fail; anything that might fail
must have been done in (c.ii).
(ii) Calls commit_creds() to apply the new credentials in a single
assignment (more or less). Possibly pdeath_signal and dumpable
should be part of struct creds.
(iii) Unlocks the task's cred_replace_mutex, thus allowing
PTRACE_ATTACH to take place.
(iv) Clears The bprm->cred pointer as the credentials it was holding
are now immutable.
(v) Calls security_bprm_committed_creds() to apply any security
alterations that must be done after the creds have been changed.
SELinux uses this to flush signals and signal handlers.
(f) If an error occurs before (d.i), bprm_free() will call abort_creds()
to destroy the proposed new credentials and will then unlock
cred_replace_mutex. No changes to the credentials will have been
made.
(2) LSM interface.
A number of functions have been changed, added or removed:
(*) security_bprm_alloc(), ->bprm_alloc_security()
(*) security_bprm_free(), ->bprm_free_security()
Removed in favour of preparing new credentials and modifying those.
(*) security_bprm_apply_creds(), ->bprm_apply_creds()
(*) security_bprm_post_apply_creds(), ->bprm_post_apply_creds()
Removed; split between security_bprm_set_creds(),
security_bprm_committing_creds() and security_bprm_committed_creds().
(*) security_bprm_set(), ->bprm_set_security()
Removed; folded into security_bprm_set_creds().
(*) security_bprm_set_creds(), ->bprm_set_creds()
New. The new credentials in bprm->creds should be checked and set up
as appropriate. bprm->cred_prepared is 0 on the first call, 1 on the
second and subsequent calls.
(*) security_bprm_committing_creds(), ->bprm_committing_creds()
(*) security_bprm_committed_creds(), ->bprm_committed_creds()
New. Apply the security effects of the new credentials. This
includes closing unauthorised files in SELinux. This function may not
fail. When the former is called, the creds haven't yet been applied
to the process; when the latter is called, they have.
The former may access bprm->cred, the latter may not.
(3) SELinux.
SELinux has a number of changes, in addition to those to support the LSM
interface changes mentioned above:
(a) The bprm_security_struct struct has been removed in favour of using
the credentials-under-construction approach.
(c) flush_unauthorized_files() now takes a cred pointer and passes it on
to inode_has_perm(), file_has_perm() and dentry_open().
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: James Morris <jmorris@namei.org>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Signed-off-by: James Morris <jmorris@namei.org>
2008-11-13 23:39:24 +00:00
|
|
|
if (old_tsec->exec_sid) {
|
|
|
|
new_tsec->sid = old_tsec->exec_sid;
|
2005-04-16 22:20:36 +00:00
|
|
|
/* Reset exec SID on execve. */
|
CRED: Make execve() take advantage of copy-on-write credentials
Make execve() take advantage of copy-on-write credentials, allowing it to set
up the credentials in advance, and then commit the whole lot after the point
of no return.
This patch and the preceding patches have been tested with the LTP SELinux
testsuite.
This patch makes several logical sets of alteration:
(1) execve().
The credential bits from struct linux_binprm are, for the most part,
replaced with a single credentials pointer (bprm->cred). This means that
all the creds can be calculated in advance and then applied at the point
of no return with no possibility of failure.
I would like to replace bprm->cap_effective with:
cap_isclear(bprm->cap_effective)
but this seems impossible due to special behaviour for processes of pid 1
(they always retain their parent's capability masks where normally they'd
be changed - see cap_bprm_set_creds()).
The following sequence of events now happens:
(a) At the start of do_execve, the current task's cred_exec_mutex is
locked to prevent PTRACE_ATTACH from obsoleting the calculation of
creds that we make.
(a) prepare_exec_creds() is then called to make a copy of the current
task's credentials and prepare it. This copy is then assigned to
bprm->cred.
This renders security_bprm_alloc() and security_bprm_free()
unnecessary, and so they've been removed.
(b) The determination of unsafe execution is now performed immediately
after (a) rather than later on in the code. The result is stored in
bprm->unsafe for future reference.
(c) prepare_binprm() is called, possibly multiple times.
(i) This applies the result of set[ug]id binaries to the new creds
attached to bprm->cred. Personality bit clearance is recorded,
but now deferred on the basis that the exec procedure may yet
fail.
(ii) This then calls the new security_bprm_set_creds(). This should
calculate the new LSM and capability credentials into *bprm->cred.
This folds together security_bprm_set() and parts of
security_bprm_apply_creds() (these two have been removed).
Anything that might fail must be done at this point.
(iii) bprm->cred_prepared is set to 1.
bprm->cred_prepared is 0 on the first pass of the security
calculations, and 1 on all subsequent passes. This allows SELinux
in (ii) to base its calculations only on the initial script and
not on the interpreter.
(d) flush_old_exec() is called to commit the task to execution. This
performs the following steps with regard to credentials:
(i) Clear pdeath_signal and set dumpable on certain circumstances that
may not be covered by commit_creds().
(ii) Clear any bits in current->personality that were deferred from
(c.i).
(e) install_exec_creds() [compute_creds() as was] is called to install the
new credentials. This performs the following steps with regard to
credentials:
(i) Calls security_bprm_committing_creds() to apply any security
requirements, such as flushing unauthorised files in SELinux, that
must be done before the credentials are changed.
This is made up of bits of security_bprm_apply_creds() and
security_bprm_post_apply_creds(), both of which have been removed.
This function is not allowed to fail; anything that might fail
must have been done in (c.ii).
(ii) Calls commit_creds() to apply the new credentials in a single
assignment (more or less). Possibly pdeath_signal and dumpable
should be part of struct creds.
(iii) Unlocks the task's cred_replace_mutex, thus allowing
PTRACE_ATTACH to take place.
(iv) Clears The bprm->cred pointer as the credentials it was holding
are now immutable.
(v) Calls security_bprm_committed_creds() to apply any security
alterations that must be done after the creds have been changed.
SELinux uses this to flush signals and signal handlers.
(f) If an error occurs before (d.i), bprm_free() will call abort_creds()
to destroy the proposed new credentials and will then unlock
cred_replace_mutex. No changes to the credentials will have been
made.
(2) LSM interface.
A number of functions have been changed, added or removed:
(*) security_bprm_alloc(), ->bprm_alloc_security()
(*) security_bprm_free(), ->bprm_free_security()
Removed in favour of preparing new credentials and modifying those.
(*) security_bprm_apply_creds(), ->bprm_apply_creds()
(*) security_bprm_post_apply_creds(), ->bprm_post_apply_creds()
Removed; split between security_bprm_set_creds(),
security_bprm_committing_creds() and security_bprm_committed_creds().
(*) security_bprm_set(), ->bprm_set_security()
Removed; folded into security_bprm_set_creds().
(*) security_bprm_set_creds(), ->bprm_set_creds()
New. The new credentials in bprm->creds should be checked and set up
as appropriate. bprm->cred_prepared is 0 on the first call, 1 on the
second and subsequent calls.
(*) security_bprm_committing_creds(), ->bprm_committing_creds()
(*) security_bprm_committed_creds(), ->bprm_committed_creds()
New. Apply the security effects of the new credentials. This
includes closing unauthorised files in SELinux. This function may not
fail. When the former is called, the creds haven't yet been applied
to the process; when the latter is called, they have.
The former may access bprm->cred, the latter may not.
(3) SELinux.
SELinux has a number of changes, in addition to those to support the LSM
interface changes mentioned above:
(a) The bprm_security_struct struct has been removed in favour of using
the credentials-under-construction approach.
(c) flush_unauthorized_files() now takes a cred pointer and passes it on
to inode_has_perm(), file_has_perm() and dentry_open().
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: James Morris <jmorris@namei.org>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Signed-off-by: James Morris <jmorris@namei.org>
2008-11-13 23:39:24 +00:00
|
|
|
new_tsec->exec_sid = 0;
|
Add PR_{GET,SET}_NO_NEW_PRIVS to prevent execve from granting privs
With this change, calling
prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0)
disables privilege granting operations at execve-time. For example, a
process will not be able to execute a setuid binary to change their uid
or gid if this bit is set. The same is true for file capabilities.
Additionally, LSM_UNSAFE_NO_NEW_PRIVS is defined to ensure that
LSMs respect the requested behavior.
To determine if the NO_NEW_PRIVS bit is set, a task may call
prctl(PR_GET_NO_NEW_PRIVS, 0, 0, 0, 0);
It returns 1 if set and 0 if it is not set. If any of the arguments are
non-zero, it will return -1 and set errno to -EINVAL.
(PR_SET_NO_NEW_PRIVS behaves similarly.)
This functionality is desired for the proposed seccomp filter patch
series. By using PR_SET_NO_NEW_PRIVS, it allows a task to modify the
system call behavior for itself and its child tasks without being
able to impact the behavior of a more privileged task.
Another potential use is making certain privileged operations
unprivileged. For example, chroot may be considered "safe" if it cannot
affect privileged tasks.
Note, this patch causes execve to fail when PR_SET_NO_NEW_PRIVS is
set and AppArmor is in use. It is fixed in a subsequent patch.
Signed-off-by: Andy Lutomirski <luto@amacapital.net>
Signed-off-by: Will Drewry <wad@chromium.org>
Acked-by: Eric Paris <eparis@redhat.com>
Acked-by: Kees Cook <keescook@chromium.org>
v18: updated change desc
v17: using new define values as per 3.4
Signed-off-by: James Morris <james.l.morris@oracle.com>
2012-04-12 21:47:50 +00:00
|
|
|
|
|
|
|
/*
|
|
|
|
* Minimize confusion: if no_new_privs and a transition is
|
|
|
|
* explicitly requested, then fail the exec.
|
|
|
|
*/
|
|
|
|
if (bprm->unsafe & LSM_UNSAFE_NO_NEW_PRIVS)
|
|
|
|
return -EPERM;
|
2005-04-16 22:20:36 +00:00
|
|
|
} else {
|
|
|
|
/* Check for a default transition on this program. */
|
CRED: Make execve() take advantage of copy-on-write credentials
Make execve() take advantage of copy-on-write credentials, allowing it to set
up the credentials in advance, and then commit the whole lot after the point
of no return.
This patch and the preceding patches have been tested with the LTP SELinux
testsuite.
This patch makes several logical sets of alteration:
(1) execve().
The credential bits from struct linux_binprm are, for the most part,
replaced with a single credentials pointer (bprm->cred). This means that
all the creds can be calculated in advance and then applied at the point
of no return with no possibility of failure.
I would like to replace bprm->cap_effective with:
cap_isclear(bprm->cap_effective)
but this seems impossible due to special behaviour for processes of pid 1
(they always retain their parent's capability masks where normally they'd
be changed - see cap_bprm_set_creds()).
The following sequence of events now happens:
(a) At the start of do_execve, the current task's cred_exec_mutex is
locked to prevent PTRACE_ATTACH from obsoleting the calculation of
creds that we make.
(a) prepare_exec_creds() is then called to make a copy of the current
task's credentials and prepare it. This copy is then assigned to
bprm->cred.
This renders security_bprm_alloc() and security_bprm_free()
unnecessary, and so they've been removed.
(b) The determination of unsafe execution is now performed immediately
after (a) rather than later on in the code. The result is stored in
bprm->unsafe for future reference.
(c) prepare_binprm() is called, possibly multiple times.
(i) This applies the result of set[ug]id binaries to the new creds
attached to bprm->cred. Personality bit clearance is recorded,
but now deferred on the basis that the exec procedure may yet
fail.
(ii) This then calls the new security_bprm_set_creds(). This should
calculate the new LSM and capability credentials into *bprm->cred.
This folds together security_bprm_set() and parts of
security_bprm_apply_creds() (these two have been removed).
Anything that might fail must be done at this point.
(iii) bprm->cred_prepared is set to 1.
bprm->cred_prepared is 0 on the first pass of the security
calculations, and 1 on all subsequent passes. This allows SELinux
in (ii) to base its calculations only on the initial script and
not on the interpreter.
(d) flush_old_exec() is called to commit the task to execution. This
performs the following steps with regard to credentials:
(i) Clear pdeath_signal and set dumpable on certain circumstances that
may not be covered by commit_creds().
(ii) Clear any bits in current->personality that were deferred from
(c.i).
(e) install_exec_creds() [compute_creds() as was] is called to install the
new credentials. This performs the following steps with regard to
credentials:
(i) Calls security_bprm_committing_creds() to apply any security
requirements, such as flushing unauthorised files in SELinux, that
must be done before the credentials are changed.
This is made up of bits of security_bprm_apply_creds() and
security_bprm_post_apply_creds(), both of which have been removed.
This function is not allowed to fail; anything that might fail
must have been done in (c.ii).
(ii) Calls commit_creds() to apply the new credentials in a single
assignment (more or less). Possibly pdeath_signal and dumpable
should be part of struct creds.
(iii) Unlocks the task's cred_replace_mutex, thus allowing
PTRACE_ATTACH to take place.
(iv) Clears The bprm->cred pointer as the credentials it was holding
are now immutable.
(v) Calls security_bprm_committed_creds() to apply any security
alterations that must be done after the creds have been changed.
SELinux uses this to flush signals and signal handlers.
(f) If an error occurs before (d.i), bprm_free() will call abort_creds()
to destroy the proposed new credentials and will then unlock
cred_replace_mutex. No changes to the credentials will have been
made.
(2) LSM interface.
A number of functions have been changed, added or removed:
(*) security_bprm_alloc(), ->bprm_alloc_security()
(*) security_bprm_free(), ->bprm_free_security()
Removed in favour of preparing new credentials and modifying those.
(*) security_bprm_apply_creds(), ->bprm_apply_creds()
(*) security_bprm_post_apply_creds(), ->bprm_post_apply_creds()
Removed; split between security_bprm_set_creds(),
security_bprm_committing_creds() and security_bprm_committed_creds().
(*) security_bprm_set(), ->bprm_set_security()
Removed; folded into security_bprm_set_creds().
(*) security_bprm_set_creds(), ->bprm_set_creds()
New. The new credentials in bprm->creds should be checked and set up
as appropriate. bprm->cred_prepared is 0 on the first call, 1 on the
second and subsequent calls.
(*) security_bprm_committing_creds(), ->bprm_committing_creds()
(*) security_bprm_committed_creds(), ->bprm_committed_creds()
New. Apply the security effects of the new credentials. This
includes closing unauthorised files in SELinux. This function may not
fail. When the former is called, the creds haven't yet been applied
to the process; when the latter is called, they have.
The former may access bprm->cred, the latter may not.
(3) SELinux.
SELinux has a number of changes, in addition to those to support the LSM
interface changes mentioned above:
(a) The bprm_security_struct struct has been removed in favour of using
the credentials-under-construction approach.
(c) flush_unauthorized_files() now takes a cred pointer and passes it on
to inode_has_perm(), file_has_perm() and dentry_open().
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: James Morris <jmorris@namei.org>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Signed-off-by: James Morris <jmorris@namei.org>
2008-11-13 23:39:24 +00:00
|
|
|
rc = security_transition_sid(old_tsec->sid, isec->sid,
|
SELinux: Use dentry name in new object labeling
Currently SELinux has rules which label new objects according to 3 criteria.
The label of the process creating the object, the label of the parent
directory, and the type of object (reg, dir, char, block, etc.) This patch
adds a 4th criteria, the dentry name, thus we can distinguish between
creating a file in an etc_t directory called shadow and one called motd.
There is no file globbing, regex parsing, or anything mystical. Either the
policy exactly (strcmp) matches the dentry name of the object or it doesn't.
This patch has no changes from today if policy does not implement the new
rules.
Signed-off-by: Eric Paris <eparis@redhat.com>
2011-02-01 16:05:40 +00:00
|
|
|
SECCLASS_PROCESS, NULL,
|
|
|
|
&new_tsec->sid);
|
2005-04-16 22:20:36 +00:00
|
|
|
if (rc)
|
|
|
|
return rc;
|
|
|
|
}
|
|
|
|
|
2012-04-04 19:01:43 +00:00
|
|
|
ad.type = LSM_AUDIT_DATA_PATH;
|
2011-04-25 16:54:27 +00:00
|
|
|
ad.u.path = bprm->file->f_path;
|
2005-04-16 22:20:36 +00:00
|
|
|
|
Add PR_{GET,SET}_NO_NEW_PRIVS to prevent execve from granting privs
With this change, calling
prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0)
disables privilege granting operations at execve-time. For example, a
process will not be able to execute a setuid binary to change their uid
or gid if this bit is set. The same is true for file capabilities.
Additionally, LSM_UNSAFE_NO_NEW_PRIVS is defined to ensure that
LSMs respect the requested behavior.
To determine if the NO_NEW_PRIVS bit is set, a task may call
prctl(PR_GET_NO_NEW_PRIVS, 0, 0, 0, 0);
It returns 1 if set and 0 if it is not set. If any of the arguments are
non-zero, it will return -1 and set errno to -EINVAL.
(PR_SET_NO_NEW_PRIVS behaves similarly.)
This functionality is desired for the proposed seccomp filter patch
series. By using PR_SET_NO_NEW_PRIVS, it allows a task to modify the
system call behavior for itself and its child tasks without being
able to impact the behavior of a more privileged task.
Another potential use is making certain privileged operations
unprivileged. For example, chroot may be considered "safe" if it cannot
affect privileged tasks.
Note, this patch causes execve to fail when PR_SET_NO_NEW_PRIVS is
set and AppArmor is in use. It is fixed in a subsequent patch.
Signed-off-by: Andy Lutomirski <luto@amacapital.net>
Signed-off-by: Will Drewry <wad@chromium.org>
Acked-by: Eric Paris <eparis@redhat.com>
Acked-by: Kees Cook <keescook@chromium.org>
v18: updated change desc
v17: using new define values as per 3.4
Signed-off-by: James Morris <james.l.morris@oracle.com>
2012-04-12 21:47:50 +00:00
|
|
|
if ((bprm->file->f_path.mnt->mnt_flags & MNT_NOSUID) ||
|
|
|
|
(bprm->unsafe & LSM_UNSAFE_NO_NEW_PRIVS))
|
CRED: Make execve() take advantage of copy-on-write credentials
Make execve() take advantage of copy-on-write credentials, allowing it to set
up the credentials in advance, and then commit the whole lot after the point
of no return.
This patch and the preceding patches have been tested with the LTP SELinux
testsuite.
This patch makes several logical sets of alteration:
(1) execve().
The credential bits from struct linux_binprm are, for the most part,
replaced with a single credentials pointer (bprm->cred). This means that
all the creds can be calculated in advance and then applied at the point
of no return with no possibility of failure.
I would like to replace bprm->cap_effective with:
cap_isclear(bprm->cap_effective)
but this seems impossible due to special behaviour for processes of pid 1
(they always retain their parent's capability masks where normally they'd
be changed - see cap_bprm_set_creds()).
The following sequence of events now happens:
(a) At the start of do_execve, the current task's cred_exec_mutex is
locked to prevent PTRACE_ATTACH from obsoleting the calculation of
creds that we make.
(a) prepare_exec_creds() is then called to make a copy of the current
task's credentials and prepare it. This copy is then assigned to
bprm->cred.
This renders security_bprm_alloc() and security_bprm_free()
unnecessary, and so they've been removed.
(b) The determination of unsafe execution is now performed immediately
after (a) rather than later on in the code. The result is stored in
bprm->unsafe for future reference.
(c) prepare_binprm() is called, possibly multiple times.
(i) This applies the result of set[ug]id binaries to the new creds
attached to bprm->cred. Personality bit clearance is recorded,
but now deferred on the basis that the exec procedure may yet
fail.
(ii) This then calls the new security_bprm_set_creds(). This should
calculate the new LSM and capability credentials into *bprm->cred.
This folds together security_bprm_set() and parts of
security_bprm_apply_creds() (these two have been removed).
Anything that might fail must be done at this point.
(iii) bprm->cred_prepared is set to 1.
bprm->cred_prepared is 0 on the first pass of the security
calculations, and 1 on all subsequent passes. This allows SELinux
in (ii) to base its calculations only on the initial script and
not on the interpreter.
(d) flush_old_exec() is called to commit the task to execution. This
performs the following steps with regard to credentials:
(i) Clear pdeath_signal and set dumpable on certain circumstances that
may not be covered by commit_creds().
(ii) Clear any bits in current->personality that were deferred from
(c.i).
(e) install_exec_creds() [compute_creds() as was] is called to install the
new credentials. This performs the following steps with regard to
credentials:
(i) Calls security_bprm_committing_creds() to apply any security
requirements, such as flushing unauthorised files in SELinux, that
must be done before the credentials are changed.
This is made up of bits of security_bprm_apply_creds() and
security_bprm_post_apply_creds(), both of which have been removed.
This function is not allowed to fail; anything that might fail
must have been done in (c.ii).
(ii) Calls commit_creds() to apply the new credentials in a single
assignment (more or less). Possibly pdeath_signal and dumpable
should be part of struct creds.
(iii) Unlocks the task's cred_replace_mutex, thus allowing
PTRACE_ATTACH to take place.
(iv) Clears The bprm->cred pointer as the credentials it was holding
are now immutable.
(v) Calls security_bprm_committed_creds() to apply any security
alterations that must be done after the creds have been changed.
SELinux uses this to flush signals and signal handlers.
(f) If an error occurs before (d.i), bprm_free() will call abort_creds()
to destroy the proposed new credentials and will then unlock
cred_replace_mutex. No changes to the credentials will have been
made.
(2) LSM interface.
A number of functions have been changed, added or removed:
(*) security_bprm_alloc(), ->bprm_alloc_security()
(*) security_bprm_free(), ->bprm_free_security()
Removed in favour of preparing new credentials and modifying those.
(*) security_bprm_apply_creds(), ->bprm_apply_creds()
(*) security_bprm_post_apply_creds(), ->bprm_post_apply_creds()
Removed; split between security_bprm_set_creds(),
security_bprm_committing_creds() and security_bprm_committed_creds().
(*) security_bprm_set(), ->bprm_set_security()
Removed; folded into security_bprm_set_creds().
(*) security_bprm_set_creds(), ->bprm_set_creds()
New. The new credentials in bprm->creds should be checked and set up
as appropriate. bprm->cred_prepared is 0 on the first call, 1 on the
second and subsequent calls.
(*) security_bprm_committing_creds(), ->bprm_committing_creds()
(*) security_bprm_committed_creds(), ->bprm_committed_creds()
New. Apply the security effects of the new credentials. This
includes closing unauthorised files in SELinux. This function may not
fail. When the former is called, the creds haven't yet been applied
to the process; when the latter is called, they have.
The former may access bprm->cred, the latter may not.
(3) SELinux.
SELinux has a number of changes, in addition to those to support the LSM
interface changes mentioned above:
(a) The bprm_security_struct struct has been removed in favour of using
the credentials-under-construction approach.
(c) flush_unauthorized_files() now takes a cred pointer and passes it on
to inode_has_perm(), file_has_perm() and dentry_open().
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: James Morris <jmorris@namei.org>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Signed-off-by: James Morris <jmorris@namei.org>
2008-11-13 23:39:24 +00:00
|
|
|
new_tsec->sid = old_tsec->sid;
|
2005-04-16 22:20:36 +00:00
|
|
|
|
CRED: Make execve() take advantage of copy-on-write credentials
Make execve() take advantage of copy-on-write credentials, allowing it to set
up the credentials in advance, and then commit the whole lot after the point
of no return.
This patch and the preceding patches have been tested with the LTP SELinux
testsuite.
This patch makes several logical sets of alteration:
(1) execve().
The credential bits from struct linux_binprm are, for the most part,
replaced with a single credentials pointer (bprm->cred). This means that
all the creds can be calculated in advance and then applied at the point
of no return with no possibility of failure.
I would like to replace bprm->cap_effective with:
cap_isclear(bprm->cap_effective)
but this seems impossible due to special behaviour for processes of pid 1
(they always retain their parent's capability masks where normally they'd
be changed - see cap_bprm_set_creds()).
The following sequence of events now happens:
(a) At the start of do_execve, the current task's cred_exec_mutex is
locked to prevent PTRACE_ATTACH from obsoleting the calculation of
creds that we make.
(a) prepare_exec_creds() is then called to make a copy of the current
task's credentials and prepare it. This copy is then assigned to
bprm->cred.
This renders security_bprm_alloc() and security_bprm_free()
unnecessary, and so they've been removed.
(b) The determination of unsafe execution is now performed immediately
after (a) rather than later on in the code. The result is stored in
bprm->unsafe for future reference.
(c) prepare_binprm() is called, possibly multiple times.
(i) This applies the result of set[ug]id binaries to the new creds
attached to bprm->cred. Personality bit clearance is recorded,
but now deferred on the basis that the exec procedure may yet
fail.
(ii) This then calls the new security_bprm_set_creds(). This should
calculate the new LSM and capability credentials into *bprm->cred.
This folds together security_bprm_set() and parts of
security_bprm_apply_creds() (these two have been removed).
Anything that might fail must be done at this point.
(iii) bprm->cred_prepared is set to 1.
bprm->cred_prepared is 0 on the first pass of the security
calculations, and 1 on all subsequent passes. This allows SELinux
in (ii) to base its calculations only on the initial script and
not on the interpreter.
(d) flush_old_exec() is called to commit the task to execution. This
performs the following steps with regard to credentials:
(i) Clear pdeath_signal and set dumpable on certain circumstances that
may not be covered by commit_creds().
(ii) Clear any bits in current->personality that were deferred from
(c.i).
(e) install_exec_creds() [compute_creds() as was] is called to install the
new credentials. This performs the following steps with regard to
credentials:
(i) Calls security_bprm_committing_creds() to apply any security
requirements, such as flushing unauthorised files in SELinux, that
must be done before the credentials are changed.
This is made up of bits of security_bprm_apply_creds() and
security_bprm_post_apply_creds(), both of which have been removed.
This function is not allowed to fail; anything that might fail
must have been done in (c.ii).
(ii) Calls commit_creds() to apply the new credentials in a single
assignment (more or less). Possibly pdeath_signal and dumpable
should be part of struct creds.
(iii) Unlocks the task's cred_replace_mutex, thus allowing
PTRACE_ATTACH to take place.
(iv) Clears The bprm->cred pointer as the credentials it was holding
are now immutable.
(v) Calls security_bprm_committed_creds() to apply any security
alterations that must be done after the creds have been changed.
SELinux uses this to flush signals and signal handlers.
(f) If an error occurs before (d.i), bprm_free() will call abort_creds()
to destroy the proposed new credentials and will then unlock
cred_replace_mutex. No changes to the credentials will have been
made.
(2) LSM interface.
A number of functions have been changed, added or removed:
(*) security_bprm_alloc(), ->bprm_alloc_security()
(*) security_bprm_free(), ->bprm_free_security()
Removed in favour of preparing new credentials and modifying those.
(*) security_bprm_apply_creds(), ->bprm_apply_creds()
(*) security_bprm_post_apply_creds(), ->bprm_post_apply_creds()
Removed; split between security_bprm_set_creds(),
security_bprm_committing_creds() and security_bprm_committed_creds().
(*) security_bprm_set(), ->bprm_set_security()
Removed; folded into security_bprm_set_creds().
(*) security_bprm_set_creds(), ->bprm_set_creds()
New. The new credentials in bprm->creds should be checked and set up
as appropriate. bprm->cred_prepared is 0 on the first call, 1 on the
second and subsequent calls.
(*) security_bprm_committing_creds(), ->bprm_committing_creds()
(*) security_bprm_committed_creds(), ->bprm_committed_creds()
New. Apply the security effects of the new credentials. This
includes closing unauthorised files in SELinux. This function may not
fail. When the former is called, the creds haven't yet been applied
to the process; when the latter is called, they have.
The former may access bprm->cred, the latter may not.
(3) SELinux.
SELinux has a number of changes, in addition to those to support the LSM
interface changes mentioned above:
(a) The bprm_security_struct struct has been removed in favour of using
the credentials-under-construction approach.
(c) flush_unauthorized_files() now takes a cred pointer and passes it on
to inode_has_perm(), file_has_perm() and dentry_open().
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: James Morris <jmorris@namei.org>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Signed-off-by: James Morris <jmorris@namei.org>
2008-11-13 23:39:24 +00:00
|
|
|
if (new_tsec->sid == old_tsec->sid) {
|
|
|
|
rc = avc_has_perm(old_tsec->sid, isec->sid,
|
2005-04-16 22:20:36 +00:00
|
|
|
SECCLASS_FILE, FILE__EXECUTE_NO_TRANS, &ad);
|
|
|
|
if (rc)
|
|
|
|
return rc;
|
|
|
|
} else {
|
|
|
|
/* Check permissions for the transition. */
|
CRED: Make execve() take advantage of copy-on-write credentials
Make execve() take advantage of copy-on-write credentials, allowing it to set
up the credentials in advance, and then commit the whole lot after the point
of no return.
This patch and the preceding patches have been tested with the LTP SELinux
testsuite.
This patch makes several logical sets of alteration:
(1) execve().
The credential bits from struct linux_binprm are, for the most part,
replaced with a single credentials pointer (bprm->cred). This means that
all the creds can be calculated in advance and then applied at the point
of no return with no possibility of failure.
I would like to replace bprm->cap_effective with:
cap_isclear(bprm->cap_effective)
but this seems impossible due to special behaviour for processes of pid 1
(they always retain their parent's capability masks where normally they'd
be changed - see cap_bprm_set_creds()).
The following sequence of events now happens:
(a) At the start of do_execve, the current task's cred_exec_mutex is
locked to prevent PTRACE_ATTACH from obsoleting the calculation of
creds that we make.
(a) prepare_exec_creds() is then called to make a copy of the current
task's credentials and prepare it. This copy is then assigned to
bprm->cred.
This renders security_bprm_alloc() and security_bprm_free()
unnecessary, and so they've been removed.
(b) The determination of unsafe execution is now performed immediately
after (a) rather than later on in the code. The result is stored in
bprm->unsafe for future reference.
(c) prepare_binprm() is called, possibly multiple times.
(i) This applies the result of set[ug]id binaries to the new creds
attached to bprm->cred. Personality bit clearance is recorded,
but now deferred on the basis that the exec procedure may yet
fail.
(ii) This then calls the new security_bprm_set_creds(). This should
calculate the new LSM and capability credentials into *bprm->cred.
This folds together security_bprm_set() and parts of
security_bprm_apply_creds() (these two have been removed).
Anything that might fail must be done at this point.
(iii) bprm->cred_prepared is set to 1.
bprm->cred_prepared is 0 on the first pass of the security
calculations, and 1 on all subsequent passes. This allows SELinux
in (ii) to base its calculations only on the initial script and
not on the interpreter.
(d) flush_old_exec() is called to commit the task to execution. This
performs the following steps with regard to credentials:
(i) Clear pdeath_signal and set dumpable on certain circumstances that
may not be covered by commit_creds().
(ii) Clear any bits in current->personality that were deferred from
(c.i).
(e) install_exec_creds() [compute_creds() as was] is called to install the
new credentials. This performs the following steps with regard to
credentials:
(i) Calls security_bprm_committing_creds() to apply any security
requirements, such as flushing unauthorised files in SELinux, that
must be done before the credentials are changed.
This is made up of bits of security_bprm_apply_creds() and
security_bprm_post_apply_creds(), both of which have been removed.
This function is not allowed to fail; anything that might fail
must have been done in (c.ii).
(ii) Calls commit_creds() to apply the new credentials in a single
assignment (more or less). Possibly pdeath_signal and dumpable
should be part of struct creds.
(iii) Unlocks the task's cred_replace_mutex, thus allowing
PTRACE_ATTACH to take place.
(iv) Clears The bprm->cred pointer as the credentials it was holding
are now immutable.
(v) Calls security_bprm_committed_creds() to apply any security
alterations that must be done after the creds have been changed.
SELinux uses this to flush signals and signal handlers.
(f) If an error occurs before (d.i), bprm_free() will call abort_creds()
to destroy the proposed new credentials and will then unlock
cred_replace_mutex. No changes to the credentials will have been
made.
(2) LSM interface.
A number of functions have been changed, added or removed:
(*) security_bprm_alloc(), ->bprm_alloc_security()
(*) security_bprm_free(), ->bprm_free_security()
Removed in favour of preparing new credentials and modifying those.
(*) security_bprm_apply_creds(), ->bprm_apply_creds()
(*) security_bprm_post_apply_creds(), ->bprm_post_apply_creds()
Removed; split between security_bprm_set_creds(),
security_bprm_committing_creds() and security_bprm_committed_creds().
(*) security_bprm_set(), ->bprm_set_security()
Removed; folded into security_bprm_set_creds().
(*) security_bprm_set_creds(), ->bprm_set_creds()
New. The new credentials in bprm->creds should be checked and set up
as appropriate. bprm->cred_prepared is 0 on the first call, 1 on the
second and subsequent calls.
(*) security_bprm_committing_creds(), ->bprm_committing_creds()
(*) security_bprm_committed_creds(), ->bprm_committed_creds()
New. Apply the security effects of the new credentials. This
includes closing unauthorised files in SELinux. This function may not
fail. When the former is called, the creds haven't yet been applied
to the process; when the latter is called, they have.
The former may access bprm->cred, the latter may not.
(3) SELinux.
SELinux has a number of changes, in addition to those to support the LSM
interface changes mentioned above:
(a) The bprm_security_struct struct has been removed in favour of using
the credentials-under-construction approach.
(c) flush_unauthorized_files() now takes a cred pointer and passes it on
to inode_has_perm(), file_has_perm() and dentry_open().
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: James Morris <jmorris@namei.org>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Signed-off-by: James Morris <jmorris@namei.org>
2008-11-13 23:39:24 +00:00
|
|
|
rc = avc_has_perm(old_tsec->sid, new_tsec->sid,
|
2005-04-16 22:20:36 +00:00
|
|
|
SECCLASS_PROCESS, PROCESS__TRANSITION, &ad);
|
|
|
|
if (rc)
|
|
|
|
return rc;
|
|
|
|
|
CRED: Make execve() take advantage of copy-on-write credentials
Make execve() take advantage of copy-on-write credentials, allowing it to set
up the credentials in advance, and then commit the whole lot after the point
of no return.
This patch and the preceding patches have been tested with the LTP SELinux
testsuite.
This patch makes several logical sets of alteration:
(1) execve().
The credential bits from struct linux_binprm are, for the most part,
replaced with a single credentials pointer (bprm->cred). This means that
all the creds can be calculated in advance and then applied at the point
of no return with no possibility of failure.
I would like to replace bprm->cap_effective with:
cap_isclear(bprm->cap_effective)
but this seems impossible due to special behaviour for processes of pid 1
(they always retain their parent's capability masks where normally they'd
be changed - see cap_bprm_set_creds()).
The following sequence of events now happens:
(a) At the start of do_execve, the current task's cred_exec_mutex is
locked to prevent PTRACE_ATTACH from obsoleting the calculation of
creds that we make.
(a) prepare_exec_creds() is then called to make a copy of the current
task's credentials and prepare it. This copy is then assigned to
bprm->cred.
This renders security_bprm_alloc() and security_bprm_free()
unnecessary, and so they've been removed.
(b) The determination of unsafe execution is now performed immediately
after (a) rather than later on in the code. The result is stored in
bprm->unsafe for future reference.
(c) prepare_binprm() is called, possibly multiple times.
(i) This applies the result of set[ug]id binaries to the new creds
attached to bprm->cred. Personality bit clearance is recorded,
but now deferred on the basis that the exec procedure may yet
fail.
(ii) This then calls the new security_bprm_set_creds(). This should
calculate the new LSM and capability credentials into *bprm->cred.
This folds together security_bprm_set() and parts of
security_bprm_apply_creds() (these two have been removed).
Anything that might fail must be done at this point.
(iii) bprm->cred_prepared is set to 1.
bprm->cred_prepared is 0 on the first pass of the security
calculations, and 1 on all subsequent passes. This allows SELinux
in (ii) to base its calculations only on the initial script and
not on the interpreter.
(d) flush_old_exec() is called to commit the task to execution. This
performs the following steps with regard to credentials:
(i) Clear pdeath_signal and set dumpable on certain circumstances that
may not be covered by commit_creds().
(ii) Clear any bits in current->personality that were deferred from
(c.i).
(e) install_exec_creds() [compute_creds() as was] is called to install the
new credentials. This performs the following steps with regard to
credentials:
(i) Calls security_bprm_committing_creds() to apply any security
requirements, such as flushing unauthorised files in SELinux, that
must be done before the credentials are changed.
This is made up of bits of security_bprm_apply_creds() and
security_bprm_post_apply_creds(), both of which have been removed.
This function is not allowed to fail; anything that might fail
must have been done in (c.ii).
(ii) Calls commit_creds() to apply the new credentials in a single
assignment (more or less). Possibly pdeath_signal and dumpable
should be part of struct creds.
(iii) Unlocks the task's cred_replace_mutex, thus allowing
PTRACE_ATTACH to take place.
(iv) Clears The bprm->cred pointer as the credentials it was holding
are now immutable.
(v) Calls security_bprm_committed_creds() to apply any security
alterations that must be done after the creds have been changed.
SELinux uses this to flush signals and signal handlers.
(f) If an error occurs before (d.i), bprm_free() will call abort_creds()
to destroy the proposed new credentials and will then unlock
cred_replace_mutex. No changes to the credentials will have been
made.
(2) LSM interface.
A number of functions have been changed, added or removed:
(*) security_bprm_alloc(), ->bprm_alloc_security()
(*) security_bprm_free(), ->bprm_free_security()
Removed in favour of preparing new credentials and modifying those.
(*) security_bprm_apply_creds(), ->bprm_apply_creds()
(*) security_bprm_post_apply_creds(), ->bprm_post_apply_creds()
Removed; split between security_bprm_set_creds(),
security_bprm_committing_creds() and security_bprm_committed_creds().
(*) security_bprm_set(), ->bprm_set_security()
Removed; folded into security_bprm_set_creds().
(*) security_bprm_set_creds(), ->bprm_set_creds()
New. The new credentials in bprm->creds should be checked and set up
as appropriate. bprm->cred_prepared is 0 on the first call, 1 on the
second and subsequent calls.
(*) security_bprm_committing_creds(), ->bprm_committing_creds()
(*) security_bprm_committed_creds(), ->bprm_committed_creds()
New. Apply the security effects of the new credentials. This
includes closing unauthorised files in SELinux. This function may not
fail. When the former is called, the creds haven't yet been applied
to the process; when the latter is called, they have.
The former may access bprm->cred, the latter may not.
(3) SELinux.
SELinux has a number of changes, in addition to those to support the LSM
interface changes mentioned above:
(a) The bprm_security_struct struct has been removed in favour of using
the credentials-under-construction approach.
(c) flush_unauthorized_files() now takes a cred pointer and passes it on
to inode_has_perm(), file_has_perm() and dentry_open().
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: James Morris <jmorris@namei.org>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Signed-off-by: James Morris <jmorris@namei.org>
2008-11-13 23:39:24 +00:00
|
|
|
rc = avc_has_perm(new_tsec->sid, isec->sid,
|
2005-04-16 22:20:36 +00:00
|
|
|
SECCLASS_FILE, FILE__ENTRYPOINT, &ad);
|
|
|
|
if (rc)
|
|
|
|
return rc;
|
|
|
|
|
CRED: Make execve() take advantage of copy-on-write credentials
Make execve() take advantage of copy-on-write credentials, allowing it to set
up the credentials in advance, and then commit the whole lot after the point
of no return.
This patch and the preceding patches have been tested with the LTP SELinux
testsuite.
This patch makes several logical sets of alteration:
(1) execve().
The credential bits from struct linux_binprm are, for the most part,
replaced with a single credentials pointer (bprm->cred). This means that
all the creds can be calculated in advance and then applied at the point
of no return with no possibility of failure.
I would like to replace bprm->cap_effective with:
cap_isclear(bprm->cap_effective)
but this seems impossible due to special behaviour for processes of pid 1
(they always retain their parent's capability masks where normally they'd
be changed - see cap_bprm_set_creds()).
The following sequence of events now happens:
(a) At the start of do_execve, the current task's cred_exec_mutex is
locked to prevent PTRACE_ATTACH from obsoleting the calculation of
creds that we make.
(a) prepare_exec_creds() is then called to make a copy of the current
task's credentials and prepare it. This copy is then assigned to
bprm->cred.
This renders security_bprm_alloc() and security_bprm_free()
unnecessary, and so they've been removed.
(b) The determination of unsafe execution is now performed immediately
after (a) rather than later on in the code. The result is stored in
bprm->unsafe for future reference.
(c) prepare_binprm() is called, possibly multiple times.
(i) This applies the result of set[ug]id binaries to the new creds
attached to bprm->cred. Personality bit clearance is recorded,
but now deferred on the basis that the exec procedure may yet
fail.
(ii) This then calls the new security_bprm_set_creds(). This should
calculate the new LSM and capability credentials into *bprm->cred.
This folds together security_bprm_set() and parts of
security_bprm_apply_creds() (these two have been removed).
Anything that might fail must be done at this point.
(iii) bprm->cred_prepared is set to 1.
bprm->cred_prepared is 0 on the first pass of the security
calculations, and 1 on all subsequent passes. This allows SELinux
in (ii) to base its calculations only on the initial script and
not on the interpreter.
(d) flush_old_exec() is called to commit the task to execution. This
performs the following steps with regard to credentials:
(i) Clear pdeath_signal and set dumpable on certain circumstances that
may not be covered by commit_creds().
(ii) Clear any bits in current->personality that were deferred from
(c.i).
(e) install_exec_creds() [compute_creds() as was] is called to install the
new credentials. This performs the following steps with regard to
credentials:
(i) Calls security_bprm_committing_creds() to apply any security
requirements, such as flushing unauthorised files in SELinux, that
must be done before the credentials are changed.
This is made up of bits of security_bprm_apply_creds() and
security_bprm_post_apply_creds(), both of which have been removed.
This function is not allowed to fail; anything that might fail
must have been done in (c.ii).
(ii) Calls commit_creds() to apply the new credentials in a single
assignment (more or less). Possibly pdeath_signal and dumpable
should be part of struct creds.
(iii) Unlocks the task's cred_replace_mutex, thus allowing
PTRACE_ATTACH to take place.
(iv) Clears The bprm->cred pointer as the credentials it was holding
are now immutable.
(v) Calls security_bprm_committed_creds() to apply any security
alterations that must be done after the creds have been changed.
SELinux uses this to flush signals and signal handlers.
(f) If an error occurs before (d.i), bprm_free() will call abort_creds()
to destroy the proposed new credentials and will then unlock
cred_replace_mutex. No changes to the credentials will have been
made.
(2) LSM interface.
A number of functions have been changed, added or removed:
(*) security_bprm_alloc(), ->bprm_alloc_security()
(*) security_bprm_free(), ->bprm_free_security()
Removed in favour of preparing new credentials and modifying those.
(*) security_bprm_apply_creds(), ->bprm_apply_creds()
(*) security_bprm_post_apply_creds(), ->bprm_post_apply_creds()
Removed; split between security_bprm_set_creds(),
security_bprm_committing_creds() and security_bprm_committed_creds().
(*) security_bprm_set(), ->bprm_set_security()
Removed; folded into security_bprm_set_creds().
(*) security_bprm_set_creds(), ->bprm_set_creds()
New. The new credentials in bprm->creds should be checked and set up
as appropriate. bprm->cred_prepared is 0 on the first call, 1 on the
second and subsequent calls.
(*) security_bprm_committing_creds(), ->bprm_committing_creds()
(*) security_bprm_committed_creds(), ->bprm_committed_creds()
New. Apply the security effects of the new credentials. This
includes closing unauthorised files in SELinux. This function may not
fail. When the former is called, the creds haven't yet been applied
to the process; when the latter is called, they have.
The former may access bprm->cred, the latter may not.
(3) SELinux.
SELinux has a number of changes, in addition to those to support the LSM
interface changes mentioned above:
(a) The bprm_security_struct struct has been removed in favour of using
the credentials-under-construction approach.
(c) flush_unauthorized_files() now takes a cred pointer and passes it on
to inode_has_perm(), file_has_perm() and dentry_open().
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: James Morris <jmorris@namei.org>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Signed-off-by: James Morris <jmorris@namei.org>
2008-11-13 23:39:24 +00:00
|
|
|
/* Check for shared state */
|
|
|
|
if (bprm->unsafe & LSM_UNSAFE_SHARE) {
|
|
|
|
rc = avc_has_perm(old_tsec->sid, new_tsec->sid,
|
|
|
|
SECCLASS_PROCESS, PROCESS__SHARE,
|
|
|
|
NULL);
|
|
|
|
if (rc)
|
|
|
|
return -EPERM;
|
|
|
|
}
|
|
|
|
|
|
|
|
/* Make sure that anyone attempting to ptrace over a task that
|
|
|
|
* changes its SID has the appropriate permit */
|
|
|
|
if (bprm->unsafe &
|
|
|
|
(LSM_UNSAFE_PTRACE | LSM_UNSAFE_PTRACE_CAP)) {
|
|
|
|
struct task_struct *tracer;
|
|
|
|
struct task_security_struct *sec;
|
|
|
|
u32 ptsid = 0;
|
|
|
|
|
|
|
|
rcu_read_lock();
|
2011-06-17 14:50:40 +00:00
|
|
|
tracer = ptrace_parent(current);
|
CRED: Make execve() take advantage of copy-on-write credentials
Make execve() take advantage of copy-on-write credentials, allowing it to set
up the credentials in advance, and then commit the whole lot after the point
of no return.
This patch and the preceding patches have been tested with the LTP SELinux
testsuite.
This patch makes several logical sets of alteration:
(1) execve().
The credential bits from struct linux_binprm are, for the most part,
replaced with a single credentials pointer (bprm->cred). This means that
all the creds can be calculated in advance and then applied at the point
of no return with no possibility of failure.
I would like to replace bprm->cap_effective with:
cap_isclear(bprm->cap_effective)
but this seems impossible due to special behaviour for processes of pid 1
(they always retain their parent's capability masks where normally they'd
be changed - see cap_bprm_set_creds()).
The following sequence of events now happens:
(a) At the start of do_execve, the current task's cred_exec_mutex is
locked to prevent PTRACE_ATTACH from obsoleting the calculation of
creds that we make.
(a) prepare_exec_creds() is then called to make a copy of the current
task's credentials and prepare it. This copy is then assigned to
bprm->cred.
This renders security_bprm_alloc() and security_bprm_free()
unnecessary, and so they've been removed.
(b) The determination of unsafe execution is now performed immediately
after (a) rather than later on in the code. The result is stored in
bprm->unsafe for future reference.
(c) prepare_binprm() is called, possibly multiple times.
(i) This applies the result of set[ug]id binaries to the new creds
attached to bprm->cred. Personality bit clearance is recorded,
but now deferred on the basis that the exec procedure may yet
fail.
(ii) This then calls the new security_bprm_set_creds(). This should
calculate the new LSM and capability credentials into *bprm->cred.
This folds together security_bprm_set() and parts of
security_bprm_apply_creds() (these two have been removed).
Anything that might fail must be done at this point.
(iii) bprm->cred_prepared is set to 1.
bprm->cred_prepared is 0 on the first pass of the security
calculations, and 1 on all subsequent passes. This allows SELinux
in (ii) to base its calculations only on the initial script and
not on the interpreter.
(d) flush_old_exec() is called to commit the task to execution. This
performs the following steps with regard to credentials:
(i) Clear pdeath_signal and set dumpable on certain circumstances that
may not be covered by commit_creds().
(ii) Clear any bits in current->personality that were deferred from
(c.i).
(e) install_exec_creds() [compute_creds() as was] is called to install the
new credentials. This performs the following steps with regard to
credentials:
(i) Calls security_bprm_committing_creds() to apply any security
requirements, such as flushing unauthorised files in SELinux, that
must be done before the credentials are changed.
This is made up of bits of security_bprm_apply_creds() and
security_bprm_post_apply_creds(), both of which have been removed.
This function is not allowed to fail; anything that might fail
must have been done in (c.ii).
(ii) Calls commit_creds() to apply the new credentials in a single
assignment (more or less). Possibly pdeath_signal and dumpable
should be part of struct creds.
(iii) Unlocks the task's cred_replace_mutex, thus allowing
PTRACE_ATTACH to take place.
(iv) Clears The bprm->cred pointer as the credentials it was holding
are now immutable.
(v) Calls security_bprm_committed_creds() to apply any security
alterations that must be done after the creds have been changed.
SELinux uses this to flush signals and signal handlers.
(f) If an error occurs before (d.i), bprm_free() will call abort_creds()
to destroy the proposed new credentials and will then unlock
cred_replace_mutex. No changes to the credentials will have been
made.
(2) LSM interface.
A number of functions have been changed, added or removed:
(*) security_bprm_alloc(), ->bprm_alloc_security()
(*) security_bprm_free(), ->bprm_free_security()
Removed in favour of preparing new credentials and modifying those.
(*) security_bprm_apply_creds(), ->bprm_apply_creds()
(*) security_bprm_post_apply_creds(), ->bprm_post_apply_creds()
Removed; split between security_bprm_set_creds(),
security_bprm_committing_creds() and security_bprm_committed_creds().
(*) security_bprm_set(), ->bprm_set_security()
Removed; folded into security_bprm_set_creds().
(*) security_bprm_set_creds(), ->bprm_set_creds()
New. The new credentials in bprm->creds should be checked and set up
as appropriate. bprm->cred_prepared is 0 on the first call, 1 on the
second and subsequent calls.
(*) security_bprm_committing_creds(), ->bprm_committing_creds()
(*) security_bprm_committed_creds(), ->bprm_committed_creds()
New. Apply the security effects of the new credentials. This
includes closing unauthorised files in SELinux. This function may not
fail. When the former is called, the creds haven't yet been applied
to the process; when the latter is called, they have.
The former may access bprm->cred, the latter may not.
(3) SELinux.
SELinux has a number of changes, in addition to those to support the LSM
interface changes mentioned above:
(a) The bprm_security_struct struct has been removed in favour of using
the credentials-under-construction approach.
(c) flush_unauthorized_files() now takes a cred pointer and passes it on
to inode_has_perm(), file_has_perm() and dentry_open().
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: James Morris <jmorris@namei.org>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Signed-off-by: James Morris <jmorris@namei.org>
2008-11-13 23:39:24 +00:00
|
|
|
if (likely(tracer != NULL)) {
|
|
|
|
sec = __task_cred(tracer)->security;
|
|
|
|
ptsid = sec->sid;
|
|
|
|
}
|
|
|
|
rcu_read_unlock();
|
|
|
|
|
|
|
|
if (ptsid != 0) {
|
|
|
|
rc = avc_has_perm(ptsid, new_tsec->sid,
|
|
|
|
SECCLASS_PROCESS,
|
|
|
|
PROCESS__PTRACE, NULL);
|
|
|
|
if (rc)
|
|
|
|
return -EPERM;
|
|
|
|
}
|
|
|
|
}
|
2005-04-16 22:20:36 +00:00
|
|
|
|
CRED: Make execve() take advantage of copy-on-write credentials
Make execve() take advantage of copy-on-write credentials, allowing it to set
up the credentials in advance, and then commit the whole lot after the point
of no return.
This patch and the preceding patches have been tested with the LTP SELinux
testsuite.
This patch makes several logical sets of alteration:
(1) execve().
The credential bits from struct linux_binprm are, for the most part,
replaced with a single credentials pointer (bprm->cred). This means that
all the creds can be calculated in advance and then applied at the point
of no return with no possibility of failure.
I would like to replace bprm->cap_effective with:
cap_isclear(bprm->cap_effective)
but this seems impossible due to special behaviour for processes of pid 1
(they always retain their parent's capability masks where normally they'd
be changed - see cap_bprm_set_creds()).
The following sequence of events now happens:
(a) At the start of do_execve, the current task's cred_exec_mutex is
locked to prevent PTRACE_ATTACH from obsoleting the calculation of
creds that we make.
(a) prepare_exec_creds() is then called to make a copy of the current
task's credentials and prepare it. This copy is then assigned to
bprm->cred.
This renders security_bprm_alloc() and security_bprm_free()
unnecessary, and so they've been removed.
(b) The determination of unsafe execution is now performed immediately
after (a) rather than later on in the code. The result is stored in
bprm->unsafe for future reference.
(c) prepare_binprm() is called, possibly multiple times.
(i) This applies the result of set[ug]id binaries to the new creds
attached to bprm->cred. Personality bit clearance is recorded,
but now deferred on the basis that the exec procedure may yet
fail.
(ii) This then calls the new security_bprm_set_creds(). This should
calculate the new LSM and capability credentials into *bprm->cred.
This folds together security_bprm_set() and parts of
security_bprm_apply_creds() (these two have been removed).
Anything that might fail must be done at this point.
(iii) bprm->cred_prepared is set to 1.
bprm->cred_prepared is 0 on the first pass of the security
calculations, and 1 on all subsequent passes. This allows SELinux
in (ii) to base its calculations only on the initial script and
not on the interpreter.
(d) flush_old_exec() is called to commit the task to execution. This
performs the following steps with regard to credentials:
(i) Clear pdeath_signal and set dumpable on certain circumstances that
may not be covered by commit_creds().
(ii) Clear any bits in current->personality that were deferred from
(c.i).
(e) install_exec_creds() [compute_creds() as was] is called to install the
new credentials. This performs the following steps with regard to
credentials:
(i) Calls security_bprm_committing_creds() to apply any security
requirements, such as flushing unauthorised files in SELinux, that
must be done before the credentials are changed.
This is made up of bits of security_bprm_apply_creds() and
security_bprm_post_apply_creds(), both of which have been removed.
This function is not allowed to fail; anything that might fail
must have been done in (c.ii).
(ii) Calls commit_creds() to apply the new credentials in a single
assignment (more or less). Possibly pdeath_signal and dumpable
should be part of struct creds.
(iii) Unlocks the task's cred_replace_mutex, thus allowing
PTRACE_ATTACH to take place.
(iv) Clears The bprm->cred pointer as the credentials it was holding
are now immutable.
(v) Calls security_bprm_committed_creds() to apply any security
alterations that must be done after the creds have been changed.
SELinux uses this to flush signals and signal handlers.
(f) If an error occurs before (d.i), bprm_free() will call abort_creds()
to destroy the proposed new credentials and will then unlock
cred_replace_mutex. No changes to the credentials will have been
made.
(2) LSM interface.
A number of functions have been changed, added or removed:
(*) security_bprm_alloc(), ->bprm_alloc_security()
(*) security_bprm_free(), ->bprm_free_security()
Removed in favour of preparing new credentials and modifying those.
(*) security_bprm_apply_creds(), ->bprm_apply_creds()
(*) security_bprm_post_apply_creds(), ->bprm_post_apply_creds()
Removed; split between security_bprm_set_creds(),
security_bprm_committing_creds() and security_bprm_committed_creds().
(*) security_bprm_set(), ->bprm_set_security()
Removed; folded into security_bprm_set_creds().
(*) security_bprm_set_creds(), ->bprm_set_creds()
New. The new credentials in bprm->creds should be checked and set up
as appropriate. bprm->cred_prepared is 0 on the first call, 1 on the
second and subsequent calls.
(*) security_bprm_committing_creds(), ->bprm_committing_creds()
(*) security_bprm_committed_creds(), ->bprm_committed_creds()
New. Apply the security effects of the new credentials. This
includes closing unauthorised files in SELinux. This function may not
fail. When the former is called, the creds haven't yet been applied
to the process; when the latter is called, they have.
The former may access bprm->cred, the latter may not.
(3) SELinux.
SELinux has a number of changes, in addition to those to support the LSM
interface changes mentioned above:
(a) The bprm_security_struct struct has been removed in favour of using
the credentials-under-construction approach.
(c) flush_unauthorized_files() now takes a cred pointer and passes it on
to inode_has_perm(), file_has_perm() and dentry_open().
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: James Morris <jmorris@namei.org>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Signed-off-by: James Morris <jmorris@namei.org>
2008-11-13 23:39:24 +00:00
|
|
|
/* Clear any possibly unsafe personality bits on exec: */
|
|
|
|
bprm->per_clear |= PER_CLEAR_ON_SETID;
|
2005-04-16 22:20:36 +00:00
|
|
|
}
|
|
|
|
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
2008-04-17 17:17:49 +00:00
|
|
|
static int selinux_bprm_secureexec(struct linux_binprm *bprm)
|
2005-04-16 22:20:36 +00:00
|
|
|
{
|
2010-04-22 18:46:19 +00:00
|
|
|
const struct task_security_struct *tsec = current_security();
|
2008-11-13 23:39:19 +00:00
|
|
|
u32 sid, osid;
|
2005-04-16 22:20:36 +00:00
|
|
|
int atsecure = 0;
|
|
|
|
|
2008-11-13 23:39:19 +00:00
|
|
|
sid = tsec->sid;
|
|
|
|
osid = tsec->osid;
|
|
|
|
|
|
|
|
if (osid != sid) {
|
2005-04-16 22:20:36 +00:00
|
|
|
/* Enable secure mode for SIDs transitions unless
|
|
|
|
the noatsecure permission is granted between
|
|
|
|
the two SIDs, i.e. ahp returns 0. */
|
2008-11-13 23:39:19 +00:00
|
|
|
atsecure = avc_has_perm(osid, sid,
|
CRED: Make execve() take advantage of copy-on-write credentials
Make execve() take advantage of copy-on-write credentials, allowing it to set
up the credentials in advance, and then commit the whole lot after the point
of no return.
This patch and the preceding patches have been tested with the LTP SELinux
testsuite.
This patch makes several logical sets of alteration:
(1) execve().
The credential bits from struct linux_binprm are, for the most part,
replaced with a single credentials pointer (bprm->cred). This means that
all the creds can be calculated in advance and then applied at the point
of no return with no possibility of failure.
I would like to replace bprm->cap_effective with:
cap_isclear(bprm->cap_effective)
but this seems impossible due to special behaviour for processes of pid 1
(they always retain their parent's capability masks where normally they'd
be changed - see cap_bprm_set_creds()).
The following sequence of events now happens:
(a) At the start of do_execve, the current task's cred_exec_mutex is
locked to prevent PTRACE_ATTACH from obsoleting the calculation of
creds that we make.
(a) prepare_exec_creds() is then called to make a copy of the current
task's credentials and prepare it. This copy is then assigned to
bprm->cred.
This renders security_bprm_alloc() and security_bprm_free()
unnecessary, and so they've been removed.
(b) The determination of unsafe execution is now performed immediately
after (a) rather than later on in the code. The result is stored in
bprm->unsafe for future reference.
(c) prepare_binprm() is called, possibly multiple times.
(i) This applies the result of set[ug]id binaries to the new creds
attached to bprm->cred. Personality bit clearance is recorded,
but now deferred on the basis that the exec procedure may yet
fail.
(ii) This then calls the new security_bprm_set_creds(). This should
calculate the new LSM and capability credentials into *bprm->cred.
This folds together security_bprm_set() and parts of
security_bprm_apply_creds() (these two have been removed).
Anything that might fail must be done at this point.
(iii) bprm->cred_prepared is set to 1.
bprm->cred_prepared is 0 on the first pass of the security
calculations, and 1 on all subsequent passes. This allows SELinux
in (ii) to base its calculations only on the initial script and
not on the interpreter.
(d) flush_old_exec() is called to commit the task to execution. This
performs the following steps with regard to credentials:
(i) Clear pdeath_signal and set dumpable on certain circumstances that
may not be covered by commit_creds().
(ii) Clear any bits in current->personality that were deferred from
(c.i).
(e) install_exec_creds() [compute_creds() as was] is called to install the
new credentials. This performs the following steps with regard to
credentials:
(i) Calls security_bprm_committing_creds() to apply any security
requirements, such as flushing unauthorised files in SELinux, that
must be done before the credentials are changed.
This is made up of bits of security_bprm_apply_creds() and
security_bprm_post_apply_creds(), both of which have been removed.
This function is not allowed to fail; anything that might fail
must have been done in (c.ii).
(ii) Calls commit_creds() to apply the new credentials in a single
assignment (more or less). Possibly pdeath_signal and dumpable
should be part of struct creds.
(iii) Unlocks the task's cred_replace_mutex, thus allowing
PTRACE_ATTACH to take place.
(iv) Clears The bprm->cred pointer as the credentials it was holding
are now immutable.
(v) Calls security_bprm_committed_creds() to apply any security
alterations that must be done after the creds have been changed.
SELinux uses this to flush signals and signal handlers.
(f) If an error occurs before (d.i), bprm_free() will call abort_creds()
to destroy the proposed new credentials and will then unlock
cred_replace_mutex. No changes to the credentials will have been
made.
(2) LSM interface.
A number of functions have been changed, added or removed:
(*) security_bprm_alloc(), ->bprm_alloc_security()
(*) security_bprm_free(), ->bprm_free_security()
Removed in favour of preparing new credentials and modifying those.
(*) security_bprm_apply_creds(), ->bprm_apply_creds()
(*) security_bprm_post_apply_creds(), ->bprm_post_apply_creds()
Removed; split between security_bprm_set_creds(),
security_bprm_committing_creds() and security_bprm_committed_creds().
(*) security_bprm_set(), ->bprm_set_security()
Removed; folded into security_bprm_set_creds().
(*) security_bprm_set_creds(), ->bprm_set_creds()
New. The new credentials in bprm->creds should be checked and set up
as appropriate. bprm->cred_prepared is 0 on the first call, 1 on the
second and subsequent calls.
(*) security_bprm_committing_creds(), ->bprm_committing_creds()
(*) security_bprm_committed_creds(), ->bprm_committed_creds()
New. Apply the security effects of the new credentials. This
includes closing unauthorised files in SELinux. This function may not
fail. When the former is called, the creds haven't yet been applied
to the process; when the latter is called, they have.
The former may access bprm->cred, the latter may not.
(3) SELinux.
SELinux has a number of changes, in addition to those to support the LSM
interface changes mentioned above:
(a) The bprm_security_struct struct has been removed in favour of using
the credentials-under-construction approach.
(c) flush_unauthorized_files() now takes a cred pointer and passes it on
to inode_has_perm(), file_has_perm() and dentry_open().
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: James Morris <jmorris@namei.org>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Signed-off-by: James Morris <jmorris@namei.org>
2008-11-13 23:39:24 +00:00
|
|
|
SECCLASS_PROCESS,
|
|
|
|
PROCESS__NOATSECURE, NULL);
|
2005-04-16 22:20:36 +00:00
|
|
|
}
|
|
|
|
|
2009-02-12 20:01:04 +00:00
|
|
|
return (atsecure || cap_bprm_secureexec(bprm));
|
2005-04-16 22:20:36 +00:00
|
|
|
}
|
|
|
|
|
2012-08-22 02:32:06 +00:00
|
|
|
static int match_file(const void *p, struct file *file, unsigned fd)
|
|
|
|
{
|
|
|
|
return file_has_perm(p, file, file_to_av(file)) ? fd + 1 : 0;
|
|
|
|
}
|
|
|
|
|
2005-04-16 22:20:36 +00:00
|
|
|
/* Derived from fs/exec.c:flush_old_files. */
|
2008-11-13 23:39:22 +00:00
|
|
|
static inline void flush_unauthorized_files(const struct cred *cred,
|
|
|
|
struct files_struct *files)
|
2005-04-16 22:20:36 +00:00
|
|
|
{
|
|
|
|
struct file *file, *devnull = NULL;
|
2006-09-26 06:32:03 +00:00
|
|
|
struct tty_struct *tty;
|
2006-12-08 10:36:04 +00:00
|
|
|
int drop_tty = 0;
|
2012-08-22 02:32:06 +00:00
|
|
|
unsigned n;
|
2005-04-16 22:20:36 +00:00
|
|
|
|
2006-12-08 10:36:04 +00:00
|
|
|
tty = get_current_tty();
|
2005-04-16 22:20:36 +00:00
|
|
|
if (tty) {
|
2010-08-17 18:37:35 +00:00
|
|
|
spin_lock(&tty_files_lock);
|
2008-10-31 21:40:00 +00:00
|
|
|
if (!list_empty(&tty->tty_files)) {
|
tty: fix fu_list abuse
tty: fix fu_list abuse
tty code abuses fu_list, which causes a bug in remount,ro handling.
If a tty device node is opened on a filesystem, then the last link to the inode
removed, the filesystem will be allowed to be remounted readonly. This is
because fs_may_remount_ro does not find the 0 link tty inode on the file sb
list (because the tty code incorrectly removed it to use for its own purpose).
This can result in a filesystem with errors after it is marked "clean".
Taking idea from Christoph's initial patch, allocate a tty private struct
at file->private_data and put our required list fields in there, linking
file and tty. This makes tty nodes behave the same way as other device nodes
and avoid meddling with the vfs, and avoids this bug.
The error handling is not trivial in the tty code, so for this bugfix, I take
the simple approach of using __GFP_NOFAIL and don't worry about memory errors.
This is not a problem because our allocator doesn't fail small allocs as a rule
anyway. So proper error handling is left as an exercise for tty hackers.
[ Arguably filesystem's device inode would ideally be divorced from the
driver's pseudo inode when it is opened, but in practice it's not clear whether
that will ever be worth implementing. ]
Cc: linux-kernel@vger.kernel.org
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Nick Piggin <npiggin@kernel.dk>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2010-08-17 18:37:36 +00:00
|
|
|
struct tty_file_private *file_priv;
|
2008-10-31 21:40:00 +00:00
|
|
|
|
2005-04-16 22:20:36 +00:00
|
|
|
/* Revalidate access to controlling tty.
|
2013-06-13 22:37:55 +00:00
|
|
|
Use file_path_has_perm on the tty path directly
|
|
|
|
rather than using file_has_perm, as this particular
|
|
|
|
open file may belong to another process and we are
|
|
|
|
only interested in the inode-based check here. */
|
tty: fix fu_list abuse
tty: fix fu_list abuse
tty code abuses fu_list, which causes a bug in remount,ro handling.
If a tty device node is opened on a filesystem, then the last link to the inode
removed, the filesystem will be allowed to be remounted readonly. This is
because fs_may_remount_ro does not find the 0 link tty inode on the file sb
list (because the tty code incorrectly removed it to use for its own purpose).
This can result in a filesystem with errors after it is marked "clean".
Taking idea from Christoph's initial patch, allocate a tty private struct
at file->private_data and put our required list fields in there, linking
file and tty. This makes tty nodes behave the same way as other device nodes
and avoid meddling with the vfs, and avoids this bug.
The error handling is not trivial in the tty code, so for this bugfix, I take
the simple approach of using __GFP_NOFAIL and don't worry about memory errors.
This is not a problem because our allocator doesn't fail small allocs as a rule
anyway. So proper error handling is left as an exercise for tty hackers.
[ Arguably filesystem's device inode would ideally be divorced from the
driver's pseudo inode when it is opened, but in practice it's not clear whether
that will ever be worth implementing. ]
Cc: linux-kernel@vger.kernel.org
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Nick Piggin <npiggin@kernel.dk>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2010-08-17 18:37:36 +00:00
|
|
|
file_priv = list_first_entry(&tty->tty_files,
|
|
|
|
struct tty_file_private, list);
|
|
|
|
file = file_priv->file;
|
2013-06-13 22:37:55 +00:00
|
|
|
if (file_path_has_perm(cred, file, FILE__READ | FILE__WRITE))
|
2006-12-08 10:36:04 +00:00
|
|
|
drop_tty = 1;
|
2005-04-16 22:20:36 +00:00
|
|
|
}
|
2010-08-17 18:37:35 +00:00
|
|
|
spin_unlock(&tty_files_lock);
|
2008-10-13 09:39:13 +00:00
|
|
|
tty_kref_put(tty);
|
2005-04-16 22:20:36 +00:00
|
|
|
}
|
2007-05-08 07:26:56 +00:00
|
|
|
/* Reset controlling tty. */
|
|
|
|
if (drop_tty)
|
|
|
|
no_tty();
|
2005-04-16 22:20:36 +00:00
|
|
|
|
|
|
|
/* Revalidate access to inherited open files. */
|
2012-08-22 02:32:06 +00:00
|
|
|
n = iterate_fd(files, 0, match_file, cred);
|
|
|
|
if (!n) /* none found? */
|
|
|
|
return;
|
2005-04-16 22:20:36 +00:00
|
|
|
|
2012-08-22 02:32:06 +00:00
|
|
|
devnull = dentry_open(&selinux_null, O_RDWR, cred);
|
2012-10-16 17:30:07 +00:00
|
|
|
if (IS_ERR(devnull))
|
|
|
|
devnull = NULL;
|
|
|
|
/* replace all the matching ones with this */
|
|
|
|
do {
|
|
|
|
replace_fd(n - 1, devnull, 0);
|
|
|
|
} while ((n = iterate_fd(files, n, match_file, cred)) != 0);
|
|
|
|
if (devnull)
|
2012-08-22 02:32:06 +00:00
|
|
|
fput(devnull);
|
2005-04-16 22:20:36 +00:00
|
|
|
}
|
|
|
|
|
CRED: Make execve() take advantage of copy-on-write credentials
Make execve() take advantage of copy-on-write credentials, allowing it to set
up the credentials in advance, and then commit the whole lot after the point
of no return.
This patch and the preceding patches have been tested with the LTP SELinux
testsuite.
This patch makes several logical sets of alteration:
(1) execve().
The credential bits from struct linux_binprm are, for the most part,
replaced with a single credentials pointer (bprm->cred). This means that
all the creds can be calculated in advance and then applied at the point
of no return with no possibility of failure.
I would like to replace bprm->cap_effective with:
cap_isclear(bprm->cap_effective)
but this seems impossible due to special behaviour for processes of pid 1
(they always retain their parent's capability masks where normally they'd
be changed - see cap_bprm_set_creds()).
The following sequence of events now happens:
(a) At the start of do_execve, the current task's cred_exec_mutex is
locked to prevent PTRACE_ATTACH from obsoleting the calculation of
creds that we make.
(a) prepare_exec_creds() is then called to make a copy of the current
task's credentials and prepare it. This copy is then assigned to
bprm->cred.
This renders security_bprm_alloc() and security_bprm_free()
unnecessary, and so they've been removed.
(b) The determination of unsafe execution is now performed immediately
after (a) rather than later on in the code. The result is stored in
bprm->unsafe for future reference.
(c) prepare_binprm() is called, possibly multiple times.
(i) This applies the result of set[ug]id binaries to the new creds
attached to bprm->cred. Personality bit clearance is recorded,
but now deferred on the basis that the exec procedure may yet
fail.
(ii) This then calls the new security_bprm_set_creds(). This should
calculate the new LSM and capability credentials into *bprm->cred.
This folds together security_bprm_set() and parts of
security_bprm_apply_creds() (these two have been removed).
Anything that might fail must be done at this point.
(iii) bprm->cred_prepared is set to 1.
bprm->cred_prepared is 0 on the first pass of the security
calculations, and 1 on all subsequent passes. This allows SELinux
in (ii) to base its calculations only on the initial script and
not on the interpreter.
(d) flush_old_exec() is called to commit the task to execution. This
performs the following steps with regard to credentials:
(i) Clear pdeath_signal and set dumpable on certain circumstances that
may not be covered by commit_creds().
(ii) Clear any bits in current->personality that were deferred from
(c.i).
(e) install_exec_creds() [compute_creds() as was] is called to install the
new credentials. This performs the following steps with regard to
credentials:
(i) Calls security_bprm_committing_creds() to apply any security
requirements, such as flushing unauthorised files in SELinux, that
must be done before the credentials are changed.
This is made up of bits of security_bprm_apply_creds() and
security_bprm_post_apply_creds(), both of which have been removed.
This function is not allowed to fail; anything that might fail
must have been done in (c.ii).
(ii) Calls commit_creds() to apply the new credentials in a single
assignment (more or less). Possibly pdeath_signal and dumpable
should be part of struct creds.
(iii) Unlocks the task's cred_replace_mutex, thus allowing
PTRACE_ATTACH to take place.
(iv) Clears The bprm->cred pointer as the credentials it was holding
are now immutable.
(v) Calls security_bprm_committed_creds() to apply any security
alterations that must be done after the creds have been changed.
SELinux uses this to flush signals and signal handlers.
(f) If an error occurs before (d.i), bprm_free() will call abort_creds()
to destroy the proposed new credentials and will then unlock
cred_replace_mutex. No changes to the credentials will have been
made.
(2) LSM interface.
A number of functions have been changed, added or removed:
(*) security_bprm_alloc(), ->bprm_alloc_security()
(*) security_bprm_free(), ->bprm_free_security()
Removed in favour of preparing new credentials and modifying those.
(*) security_bprm_apply_creds(), ->bprm_apply_creds()
(*) security_bprm_post_apply_creds(), ->bprm_post_apply_creds()
Removed; split between security_bprm_set_creds(),
security_bprm_committing_creds() and security_bprm_committed_creds().
(*) security_bprm_set(), ->bprm_set_security()
Removed; folded into security_bprm_set_creds().
(*) security_bprm_set_creds(), ->bprm_set_creds()
New. The new credentials in bprm->creds should be checked and set up
as appropriate. bprm->cred_prepared is 0 on the first call, 1 on the
second and subsequent calls.
(*) security_bprm_committing_creds(), ->bprm_committing_creds()
(*) security_bprm_committed_creds(), ->bprm_committed_creds()
New. Apply the security effects of the new credentials. This
includes closing unauthorised files in SELinux. This function may not
fail. When the former is called, the creds haven't yet been applied
to the process; when the latter is called, they have.
The former may access bprm->cred, the latter may not.
(3) SELinux.
SELinux has a number of changes, in addition to those to support the LSM
interface changes mentioned above:
(a) The bprm_security_struct struct has been removed in favour of using
the credentials-under-construction approach.
(c) flush_unauthorized_files() now takes a cred pointer and passes it on
to inode_has_perm(), file_has_perm() and dentry_open().
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: James Morris <jmorris@namei.org>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Signed-off-by: James Morris <jmorris@namei.org>
2008-11-13 23:39:24 +00:00
|
|
|
/*
|
|
|
|
* Prepare a process for imminent new credential changes due to exec
|
|
|
|
*/
|
|
|
|
static void selinux_bprm_committing_creds(struct linux_binprm *bprm)
|
2005-04-16 22:20:36 +00:00
|
|
|
{
|
CRED: Make execve() take advantage of copy-on-write credentials
Make execve() take advantage of copy-on-write credentials, allowing it to set
up the credentials in advance, and then commit the whole lot after the point
of no return.
This patch and the preceding patches have been tested with the LTP SELinux
testsuite.
This patch makes several logical sets of alteration:
(1) execve().
The credential bits from struct linux_binprm are, for the most part,
replaced with a single credentials pointer (bprm->cred). This means that
all the creds can be calculated in advance and then applied at the point
of no return with no possibility of failure.
I would like to replace bprm->cap_effective with:
cap_isclear(bprm->cap_effective)
but this seems impossible due to special behaviour for processes of pid 1
(they always retain their parent's capability masks where normally they'd
be changed - see cap_bprm_set_creds()).
The following sequence of events now happens:
(a) At the start of do_execve, the current task's cred_exec_mutex is
locked to prevent PTRACE_ATTACH from obsoleting the calculation of
creds that we make.
(a) prepare_exec_creds() is then called to make a copy of the current
task's credentials and prepare it. This copy is then assigned to
bprm->cred.
This renders security_bprm_alloc() and security_bprm_free()
unnecessary, and so they've been removed.
(b) The determination of unsafe execution is now performed immediately
after (a) rather than later on in the code. The result is stored in
bprm->unsafe for future reference.
(c) prepare_binprm() is called, possibly multiple times.
(i) This applies the result of set[ug]id binaries to the new creds
attached to bprm->cred. Personality bit clearance is recorded,
but now deferred on the basis that the exec procedure may yet
fail.
(ii) This then calls the new security_bprm_set_creds(). This should
calculate the new LSM and capability credentials into *bprm->cred.
This folds together security_bprm_set() and parts of
security_bprm_apply_creds() (these two have been removed).
Anything that might fail must be done at this point.
(iii) bprm->cred_prepared is set to 1.
bprm->cred_prepared is 0 on the first pass of the security
calculations, and 1 on all subsequent passes. This allows SELinux
in (ii) to base its calculations only on the initial script and
not on the interpreter.
(d) flush_old_exec() is called to commit the task to execution. This
performs the following steps with regard to credentials:
(i) Clear pdeath_signal and set dumpable on certain circumstances that
may not be covered by commit_creds().
(ii) Clear any bits in current->personality that were deferred from
(c.i).
(e) install_exec_creds() [compute_creds() as was] is called to install the
new credentials. This performs the following steps with regard to
credentials:
(i) Calls security_bprm_committing_creds() to apply any security
requirements, such as flushing unauthorised files in SELinux, that
must be done before the credentials are changed.
This is made up of bits of security_bprm_apply_creds() and
security_bprm_post_apply_creds(), both of which have been removed.
This function is not allowed to fail; anything that might fail
must have been done in (c.ii).
(ii) Calls commit_creds() to apply the new credentials in a single
assignment (more or less). Possibly pdeath_signal and dumpable
should be part of struct creds.
(iii) Unlocks the task's cred_replace_mutex, thus allowing
PTRACE_ATTACH to take place.
(iv) Clears The bprm->cred pointer as the credentials it was holding
are now immutable.
(v) Calls security_bprm_committed_creds() to apply any security
alterations that must be done after the creds have been changed.
SELinux uses this to flush signals and signal handlers.
(f) If an error occurs before (d.i), bprm_free() will call abort_creds()
to destroy the proposed new credentials and will then unlock
cred_replace_mutex. No changes to the credentials will have been
made.
(2) LSM interface.
A number of functions have been changed, added or removed:
(*) security_bprm_alloc(), ->bprm_alloc_security()
(*) security_bprm_free(), ->bprm_free_security()
Removed in favour of preparing new credentials and modifying those.
(*) security_bprm_apply_creds(), ->bprm_apply_creds()
(*) security_bprm_post_apply_creds(), ->bprm_post_apply_creds()
Removed; split between security_bprm_set_creds(),
security_bprm_committing_creds() and security_bprm_committed_creds().
(*) security_bprm_set(), ->bprm_set_security()
Removed; folded into security_bprm_set_creds().
(*) security_bprm_set_creds(), ->bprm_set_creds()
New. The new credentials in bprm->creds should be checked and set up
as appropriate. bprm->cred_prepared is 0 on the first call, 1 on the
second and subsequent calls.
(*) security_bprm_committing_creds(), ->bprm_committing_creds()
(*) security_bprm_committed_creds(), ->bprm_committed_creds()
New. Apply the security effects of the new credentials. This
includes closing unauthorised files in SELinux. This function may not
fail. When the former is called, the creds haven't yet been applied
to the process; when the latter is called, they have.
The former may access bprm->cred, the latter may not.
(3) SELinux.
SELinux has a number of changes, in addition to those to support the LSM
interface changes mentioned above:
(a) The bprm_security_struct struct has been removed in favour of using
the credentials-under-construction approach.
(c) flush_unauthorized_files() now takes a cred pointer and passes it on
to inode_has_perm(), file_has_perm() and dentry_open().
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: James Morris <jmorris@namei.org>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Signed-off-by: James Morris <jmorris@namei.org>
2008-11-13 23:39:24 +00:00
|
|
|
struct task_security_struct *new_tsec;
|
|
|
|
struct rlimit *rlim, *initrlim;
|
|
|
|
int rc, i;
|
CRED: Inaugurate COW credentials
Inaugurate copy-on-write credentials management. This uses RCU to manage the
credentials pointer in the task_struct with respect to accesses by other tasks.
A process may only modify its own credentials, and so does not need locking to
access or modify its own credentials.
A mutex (cred_replace_mutex) is added to the task_struct to control the effect
of PTRACE_ATTACHED on credential calculations, particularly with respect to
execve().
With this patch, the contents of an active credentials struct may not be
changed directly; rather a new set of credentials must be prepared, modified
and committed using something like the following sequence of events:
struct cred *new = prepare_creds();
int ret = blah(new);
if (ret < 0) {
abort_creds(new);
return ret;
}
return commit_creds(new);
There are some exceptions to this rule: the keyrings pointed to by the active
credentials may be instantiated - keyrings violate the COW rule as managing
COW keyrings is tricky, given that it is possible for a task to directly alter
the keys in a keyring in use by another task.
To help enforce this, various pointers to sets of credentials, such as those in
the task_struct, are declared const. The purpose of this is compile-time
discouragement of altering credentials through those pointers. Once a set of
credentials has been made public through one of these pointers, it may not be
modified, except under special circumstances:
(1) Its reference count may incremented and decremented.
(2) The keyrings to which it points may be modified, but not replaced.
The only safe way to modify anything else is to create a replacement and commit
using the functions described in Documentation/credentials.txt (which will be
added by a later patch).
This patch and the preceding patches have been tested with the LTP SELinux
testsuite.
This patch makes several logical sets of alteration:
(1) execve().
This now prepares and commits credentials in various places in the
security code rather than altering the current creds directly.
(2) Temporary credential overrides.
do_coredump() and sys_faccessat() now prepare their own credentials and
temporarily override the ones currently on the acting thread, whilst
preventing interference from other threads by holding cred_replace_mutex
on the thread being dumped.
This will be replaced in a future patch by something that hands down the
credentials directly to the functions being called, rather than altering
the task's objective credentials.
(3) LSM interface.
A number of functions have been changed, added or removed:
(*) security_capset_check(), ->capset_check()
(*) security_capset_set(), ->capset_set()
Removed in favour of security_capset().
(*) security_capset(), ->capset()
New. This is passed a pointer to the new creds, a pointer to the old
creds and the proposed capability sets. It should fill in the new
creds or return an error. All pointers, barring the pointer to the
new creds, are now const.
(*) security_bprm_apply_creds(), ->bprm_apply_creds()
Changed; now returns a value, which will cause the process to be
killed if it's an error.
(*) security_task_alloc(), ->task_alloc_security()
Removed in favour of security_prepare_creds().
(*) security_cred_free(), ->cred_free()
New. Free security data attached to cred->security.
(*) security_prepare_creds(), ->cred_prepare()
New. Duplicate any security data attached to cred->security.
(*) security_commit_creds(), ->cred_commit()
New. Apply any security effects for the upcoming installation of new
security by commit_creds().
(*) security_task_post_setuid(), ->task_post_setuid()
Removed in favour of security_task_fix_setuid().
(*) security_task_fix_setuid(), ->task_fix_setuid()
Fix up the proposed new credentials for setuid(). This is used by
cap_set_fix_setuid() to implicitly adjust capabilities in line with
setuid() changes. Changes are made to the new credentials, rather
than the task itself as in security_task_post_setuid().
(*) security_task_reparent_to_init(), ->task_reparent_to_init()
Removed. Instead the task being reparented to init is referred
directly to init's credentials.
NOTE! This results in the loss of some state: SELinux's osid no
longer records the sid of the thread that forked it.
(*) security_key_alloc(), ->key_alloc()
(*) security_key_permission(), ->key_permission()
Changed. These now take cred pointers rather than task pointers to
refer to the security context.
(4) sys_capset().
This has been simplified and uses less locking. The LSM functions it
calls have been merged.
(5) reparent_to_kthreadd().
This gives the current thread the same credentials as init by simply using
commit_thread() to point that way.
(6) __sigqueue_alloc() and switch_uid()
__sigqueue_alloc() can't stop the target task from changing its creds
beneath it, so this function gets a reference to the currently applicable
user_struct which it then passes into the sigqueue struct it returns if
successful.
switch_uid() is now called from commit_creds(), and possibly should be
folded into that. commit_creds() should take care of protecting
__sigqueue_alloc().
(7) [sg]et[ug]id() and co and [sg]et_current_groups.
The set functions now all use prepare_creds(), commit_creds() and
abort_creds() to build and check a new set of credentials before applying
it.
security_task_set[ug]id() is called inside the prepared section. This
guarantees that nothing else will affect the creds until we've finished.
The calling of set_dumpable() has been moved into commit_creds().
Much of the functionality of set_user() has been moved into
commit_creds().
The get functions all simply access the data directly.
(8) security_task_prctl() and cap_task_prctl().
security_task_prctl() has been modified to return -ENOSYS if it doesn't
want to handle a function, or otherwise return the return value directly
rather than through an argument.
Additionally, cap_task_prctl() now prepares a new set of credentials, even
if it doesn't end up using it.
(9) Keyrings.
A number of changes have been made to the keyrings code:
(a) switch_uid_keyring(), copy_keys(), exit_keys() and suid_keys() have
all been dropped and built in to the credentials functions directly.
They may want separating out again later.
(b) key_alloc() and search_process_keyrings() now take a cred pointer
rather than a task pointer to specify the security context.
(c) copy_creds() gives a new thread within the same thread group a new
thread keyring if its parent had one, otherwise it discards the thread
keyring.
(d) The authorisation key now points directly to the credentials to extend
the search into rather pointing to the task that carries them.
(e) Installing thread, process or session keyrings causes a new set of
credentials to be created, even though it's not strictly necessary for
process or session keyrings (they're shared).
(10) Usermode helper.
The usermode helper code now carries a cred struct pointer in its
subprocess_info struct instead of a new session keyring pointer. This set
of credentials is derived from init_cred and installed on the new process
after it has been cloned.
call_usermodehelper_setup() allocates the new credentials and
call_usermodehelper_freeinfo() discards them if they haven't been used. A
special cred function (prepare_usermodeinfo_creds()) is provided
specifically for call_usermodehelper_setup() to call.
call_usermodehelper_setkeys() adjusts the credentials to sport the
supplied keyring as the new session keyring.
(11) SELinux.
SELinux has a number of changes, in addition to those to support the LSM
interface changes mentioned above:
(a) selinux_setprocattr() no longer does its check for whether the
current ptracer can access processes with the new SID inside the lock
that covers getting the ptracer's SID. Whilst this lock ensures that
the check is done with the ptracer pinned, the result is only valid
until the lock is released, so there's no point doing it inside the
lock.
(12) is_single_threaded().
This function has been extracted from selinux_setprocattr() and put into
a file of its own in the lib/ directory as join_session_keyring() now
wants to use it too.
The code in SELinux just checked to see whether a task shared mm_structs
with other tasks (CLONE_VM), but that isn't good enough. We really want
to know if they're part of the same thread group (CLONE_THREAD).
(13) nfsd.
The NFS server daemon now has to use the COW credentials to set the
credentials it is going to use. It really needs to pass the credentials
down to the functions it calls, but it can't do that until other patches
in this series have been applied.
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: James Morris <jmorris@namei.org>
Signed-off-by: James Morris <jmorris@namei.org>
2008-11-13 23:39:23 +00:00
|
|
|
|
CRED: Make execve() take advantage of copy-on-write credentials
Make execve() take advantage of copy-on-write credentials, allowing it to set
up the credentials in advance, and then commit the whole lot after the point
of no return.
This patch and the preceding patches have been tested with the LTP SELinux
testsuite.
This patch makes several logical sets of alteration:
(1) execve().
The credential bits from struct linux_binprm are, for the most part,
replaced with a single credentials pointer (bprm->cred). This means that
all the creds can be calculated in advance and then applied at the point
of no return with no possibility of failure.
I would like to replace bprm->cap_effective with:
cap_isclear(bprm->cap_effective)
but this seems impossible due to special behaviour for processes of pid 1
(they always retain their parent's capability masks where normally they'd
be changed - see cap_bprm_set_creds()).
The following sequence of events now happens:
(a) At the start of do_execve, the current task's cred_exec_mutex is
locked to prevent PTRACE_ATTACH from obsoleting the calculation of
creds that we make.
(a) prepare_exec_creds() is then called to make a copy of the current
task's credentials and prepare it. This copy is then assigned to
bprm->cred.
This renders security_bprm_alloc() and security_bprm_free()
unnecessary, and so they've been removed.
(b) The determination of unsafe execution is now performed immediately
after (a) rather than later on in the code. The result is stored in
bprm->unsafe for future reference.
(c) prepare_binprm() is called, possibly multiple times.
(i) This applies the result of set[ug]id binaries to the new creds
attached to bprm->cred. Personality bit clearance is recorded,
but now deferred on the basis that the exec procedure may yet
fail.
(ii) This then calls the new security_bprm_set_creds(). This should
calculate the new LSM and capability credentials into *bprm->cred.
This folds together security_bprm_set() and parts of
security_bprm_apply_creds() (these two have been removed).
Anything that might fail must be done at this point.
(iii) bprm->cred_prepared is set to 1.
bprm->cred_prepared is 0 on the first pass of the security
calculations, and 1 on all subsequent passes. This allows SELinux
in (ii) to base its calculations only on the initial script and
not on the interpreter.
(d) flush_old_exec() is called to commit the task to execution. This
performs the following steps with regard to credentials:
(i) Clear pdeath_signal and set dumpable on certain circumstances that
may not be covered by commit_creds().
(ii) Clear any bits in current->personality that were deferred from
(c.i).
(e) install_exec_creds() [compute_creds() as was] is called to install the
new credentials. This performs the following steps with regard to
credentials:
(i) Calls security_bprm_committing_creds() to apply any security
requirements, such as flushing unauthorised files in SELinux, that
must be done before the credentials are changed.
This is made up of bits of security_bprm_apply_creds() and
security_bprm_post_apply_creds(), both of which have been removed.
This function is not allowed to fail; anything that might fail
must have been done in (c.ii).
(ii) Calls commit_creds() to apply the new credentials in a single
assignment (more or less). Possibly pdeath_signal and dumpable
should be part of struct creds.
(iii) Unlocks the task's cred_replace_mutex, thus allowing
PTRACE_ATTACH to take place.
(iv) Clears The bprm->cred pointer as the credentials it was holding
are now immutable.
(v) Calls security_bprm_committed_creds() to apply any security
alterations that must be done after the creds have been changed.
SELinux uses this to flush signals and signal handlers.
(f) If an error occurs before (d.i), bprm_free() will call abort_creds()
to destroy the proposed new credentials and will then unlock
cred_replace_mutex. No changes to the credentials will have been
made.
(2) LSM interface.
A number of functions have been changed, added or removed:
(*) security_bprm_alloc(), ->bprm_alloc_security()
(*) security_bprm_free(), ->bprm_free_security()
Removed in favour of preparing new credentials and modifying those.
(*) security_bprm_apply_creds(), ->bprm_apply_creds()
(*) security_bprm_post_apply_creds(), ->bprm_post_apply_creds()
Removed; split between security_bprm_set_creds(),
security_bprm_committing_creds() and security_bprm_committed_creds().
(*) security_bprm_set(), ->bprm_set_security()
Removed; folded into security_bprm_set_creds().
(*) security_bprm_set_creds(), ->bprm_set_creds()
New. The new credentials in bprm->creds should be checked and set up
as appropriate. bprm->cred_prepared is 0 on the first call, 1 on the
second and subsequent calls.
(*) security_bprm_committing_creds(), ->bprm_committing_creds()
(*) security_bprm_committed_creds(), ->bprm_committed_creds()
New. Apply the security effects of the new credentials. This
includes closing unauthorised files in SELinux. This function may not
fail. When the former is called, the creds haven't yet been applied
to the process; when the latter is called, they have.
The former may access bprm->cred, the latter may not.
(3) SELinux.
SELinux has a number of changes, in addition to those to support the LSM
interface changes mentioned above:
(a) The bprm_security_struct struct has been removed in favour of using
the credentials-under-construction approach.
(c) flush_unauthorized_files() now takes a cred pointer and passes it on
to inode_has_perm(), file_has_perm() and dentry_open().
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: James Morris <jmorris@namei.org>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Signed-off-by: James Morris <jmorris@namei.org>
2008-11-13 23:39:24 +00:00
|
|
|
new_tsec = bprm->cred->security;
|
|
|
|
if (new_tsec->sid == new_tsec->osid)
|
|
|
|
return;
|
2005-04-16 22:20:36 +00:00
|
|
|
|
CRED: Make execve() take advantage of copy-on-write credentials
Make execve() take advantage of copy-on-write credentials, allowing it to set
up the credentials in advance, and then commit the whole lot after the point
of no return.
This patch and the preceding patches have been tested with the LTP SELinux
testsuite.
This patch makes several logical sets of alteration:
(1) execve().
The credential bits from struct linux_binprm are, for the most part,
replaced with a single credentials pointer (bprm->cred). This means that
all the creds can be calculated in advance and then applied at the point
of no return with no possibility of failure.
I would like to replace bprm->cap_effective with:
cap_isclear(bprm->cap_effective)
but this seems impossible due to special behaviour for processes of pid 1
(they always retain their parent's capability masks where normally they'd
be changed - see cap_bprm_set_creds()).
The following sequence of events now happens:
(a) At the start of do_execve, the current task's cred_exec_mutex is
locked to prevent PTRACE_ATTACH from obsoleting the calculation of
creds that we make.
(a) prepare_exec_creds() is then called to make a copy of the current
task's credentials and prepare it. This copy is then assigned to
bprm->cred.
This renders security_bprm_alloc() and security_bprm_free()
unnecessary, and so they've been removed.
(b) The determination of unsafe execution is now performed immediately
after (a) rather than later on in the code. The result is stored in
bprm->unsafe for future reference.
(c) prepare_binprm() is called, possibly multiple times.
(i) This applies the result of set[ug]id binaries to the new creds
attached to bprm->cred. Personality bit clearance is recorded,
but now deferred on the basis that the exec procedure may yet
fail.
(ii) This then calls the new security_bprm_set_creds(). This should
calculate the new LSM and capability credentials into *bprm->cred.
This folds together security_bprm_set() and parts of
security_bprm_apply_creds() (these two have been removed).
Anything that might fail must be done at this point.
(iii) bprm->cred_prepared is set to 1.
bprm->cred_prepared is 0 on the first pass of the security
calculations, and 1 on all subsequent passes. This allows SELinux
in (ii) to base its calculations only on the initial script and
not on the interpreter.
(d) flush_old_exec() is called to commit the task to execution. This
performs the following steps with regard to credentials:
(i) Clear pdeath_signal and set dumpable on certain circumstances that
may not be covered by commit_creds().
(ii) Clear any bits in current->personality that were deferred from
(c.i).
(e) install_exec_creds() [compute_creds() as was] is called to install the
new credentials. This performs the following steps with regard to
credentials:
(i) Calls security_bprm_committing_creds() to apply any security
requirements, such as flushing unauthorised files in SELinux, that
must be done before the credentials are changed.
This is made up of bits of security_bprm_apply_creds() and
security_bprm_post_apply_creds(), both of which have been removed.
This function is not allowed to fail; anything that might fail
must have been done in (c.ii).
(ii) Calls commit_creds() to apply the new credentials in a single
assignment (more or less). Possibly pdeath_signal and dumpable
should be part of struct creds.
(iii) Unlocks the task's cred_replace_mutex, thus allowing
PTRACE_ATTACH to take place.
(iv) Clears The bprm->cred pointer as the credentials it was holding
are now immutable.
(v) Calls security_bprm_committed_creds() to apply any security
alterations that must be done after the creds have been changed.
SELinux uses this to flush signals and signal handlers.
(f) If an error occurs before (d.i), bprm_free() will call abort_creds()
to destroy the proposed new credentials and will then unlock
cred_replace_mutex. No changes to the credentials will have been
made.
(2) LSM interface.
A number of functions have been changed, added or removed:
(*) security_bprm_alloc(), ->bprm_alloc_security()
(*) security_bprm_free(), ->bprm_free_security()
Removed in favour of preparing new credentials and modifying those.
(*) security_bprm_apply_creds(), ->bprm_apply_creds()
(*) security_bprm_post_apply_creds(), ->bprm_post_apply_creds()
Removed; split between security_bprm_set_creds(),
security_bprm_committing_creds() and security_bprm_committed_creds().
(*) security_bprm_set(), ->bprm_set_security()
Removed; folded into security_bprm_set_creds().
(*) security_bprm_set_creds(), ->bprm_set_creds()
New. The new credentials in bprm->creds should be checked and set up
as appropriate. bprm->cred_prepared is 0 on the first call, 1 on the
second and subsequent calls.
(*) security_bprm_committing_creds(), ->bprm_committing_creds()
(*) security_bprm_committed_creds(), ->bprm_committed_creds()
New. Apply the security effects of the new credentials. This
includes closing unauthorised files in SELinux. This function may not
fail. When the former is called, the creds haven't yet been applied
to the process; when the latter is called, they have.
The former may access bprm->cred, the latter may not.
(3) SELinux.
SELinux has a number of changes, in addition to those to support the LSM
interface changes mentioned above:
(a) The bprm_security_struct struct has been removed in favour of using
the credentials-under-construction approach.
(c) flush_unauthorized_files() now takes a cred pointer and passes it on
to inode_has_perm(), file_has_perm() and dentry_open().
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: James Morris <jmorris@namei.org>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Signed-off-by: James Morris <jmorris@namei.org>
2008-11-13 23:39:24 +00:00
|
|
|
/* Close files for which the new task SID is not authorized. */
|
|
|
|
flush_unauthorized_files(bprm->cred, current->files);
|
2008-03-26 22:46:39 +00:00
|
|
|
|
CRED: Make execve() take advantage of copy-on-write credentials
Make execve() take advantage of copy-on-write credentials, allowing it to set
up the credentials in advance, and then commit the whole lot after the point
of no return.
This patch and the preceding patches have been tested with the LTP SELinux
testsuite.
This patch makes several logical sets of alteration:
(1) execve().
The credential bits from struct linux_binprm are, for the most part,
replaced with a single credentials pointer (bprm->cred). This means that
all the creds can be calculated in advance and then applied at the point
of no return with no possibility of failure.
I would like to replace bprm->cap_effective with:
cap_isclear(bprm->cap_effective)
but this seems impossible due to special behaviour for processes of pid 1
(they always retain their parent's capability masks where normally they'd
be changed - see cap_bprm_set_creds()).
The following sequence of events now happens:
(a) At the start of do_execve, the current task's cred_exec_mutex is
locked to prevent PTRACE_ATTACH from obsoleting the calculation of
creds that we make.
(a) prepare_exec_creds() is then called to make a copy of the current
task's credentials and prepare it. This copy is then assigned to
bprm->cred.
This renders security_bprm_alloc() and security_bprm_free()
unnecessary, and so they've been removed.
(b) The determination of unsafe execution is now performed immediately
after (a) rather than later on in the code. The result is stored in
bprm->unsafe for future reference.
(c) prepare_binprm() is called, possibly multiple times.
(i) This applies the result of set[ug]id binaries to the new creds
attached to bprm->cred. Personality bit clearance is recorded,
but now deferred on the basis that the exec procedure may yet
fail.
(ii) This then calls the new security_bprm_set_creds(). This should
calculate the new LSM and capability credentials into *bprm->cred.
This folds together security_bprm_set() and parts of
security_bprm_apply_creds() (these two have been removed).
Anything that might fail must be done at this point.
(iii) bprm->cred_prepared is set to 1.
bprm->cred_prepared is 0 on the first pass of the security
calculations, and 1 on all subsequent passes. This allows SELinux
in (ii) to base its calculations only on the initial script and
not on the interpreter.
(d) flush_old_exec() is called to commit the task to execution. This
performs the following steps with regard to credentials:
(i) Clear pdeath_signal and set dumpable on certain circumstances that
may not be covered by commit_creds().
(ii) Clear any bits in current->personality that were deferred from
(c.i).
(e) install_exec_creds() [compute_creds() as was] is called to install the
new credentials. This performs the following steps with regard to
credentials:
(i) Calls security_bprm_committing_creds() to apply any security
requirements, such as flushing unauthorised files in SELinux, that
must be done before the credentials are changed.
This is made up of bits of security_bprm_apply_creds() and
security_bprm_post_apply_creds(), both of which have been removed.
This function is not allowed to fail; anything that might fail
must have been done in (c.ii).
(ii) Calls commit_creds() to apply the new credentials in a single
assignment (more or less). Possibly pdeath_signal and dumpable
should be part of struct creds.
(iii) Unlocks the task's cred_replace_mutex, thus allowing
PTRACE_ATTACH to take place.
(iv) Clears The bprm->cred pointer as the credentials it was holding
are now immutable.
(v) Calls security_bprm_committed_creds() to apply any security
alterations that must be done after the creds have been changed.
SELinux uses this to flush signals and signal handlers.
(f) If an error occurs before (d.i), bprm_free() will call abort_creds()
to destroy the proposed new credentials and will then unlock
cred_replace_mutex. No changes to the credentials will have been
made.
(2) LSM interface.
A number of functions have been changed, added or removed:
(*) security_bprm_alloc(), ->bprm_alloc_security()
(*) security_bprm_free(), ->bprm_free_security()
Removed in favour of preparing new credentials and modifying those.
(*) security_bprm_apply_creds(), ->bprm_apply_creds()
(*) security_bprm_post_apply_creds(), ->bprm_post_apply_creds()
Removed; split between security_bprm_set_creds(),
security_bprm_committing_creds() and security_bprm_committed_creds().
(*) security_bprm_set(), ->bprm_set_security()
Removed; folded into security_bprm_set_creds().
(*) security_bprm_set_creds(), ->bprm_set_creds()
New. The new credentials in bprm->creds should be checked and set up
as appropriate. bprm->cred_prepared is 0 on the first call, 1 on the
second and subsequent calls.
(*) security_bprm_committing_creds(), ->bprm_committing_creds()
(*) security_bprm_committed_creds(), ->bprm_committed_creds()
New. Apply the security effects of the new credentials. This
includes closing unauthorised files in SELinux. This function may not
fail. When the former is called, the creds haven't yet been applied
to the process; when the latter is called, they have.
The former may access bprm->cred, the latter may not.
(3) SELinux.
SELinux has a number of changes, in addition to those to support the LSM
interface changes mentioned above:
(a) The bprm_security_struct struct has been removed in favour of using
the credentials-under-construction approach.
(c) flush_unauthorized_files() now takes a cred pointer and passes it on
to inode_has_perm(), file_has_perm() and dentry_open().
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: James Morris <jmorris@namei.org>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Signed-off-by: James Morris <jmorris@namei.org>
2008-11-13 23:39:24 +00:00
|
|
|
/* Always clear parent death signal on SID transitions. */
|
|
|
|
current->pdeath_signal = 0;
|
2008-03-26 22:46:39 +00:00
|
|
|
|
CRED: Make execve() take advantage of copy-on-write credentials
Make execve() take advantage of copy-on-write credentials, allowing it to set
up the credentials in advance, and then commit the whole lot after the point
of no return.
This patch and the preceding patches have been tested with the LTP SELinux
testsuite.
This patch makes several logical sets of alteration:
(1) execve().
The credential bits from struct linux_binprm are, for the most part,
replaced with a single credentials pointer (bprm->cred). This means that
all the creds can be calculated in advance and then applied at the point
of no return with no possibility of failure.
I would like to replace bprm->cap_effective with:
cap_isclear(bprm->cap_effective)
but this seems impossible due to special behaviour for processes of pid 1
(they always retain their parent's capability masks where normally they'd
be changed - see cap_bprm_set_creds()).
The following sequence of events now happens:
(a) At the start of do_execve, the current task's cred_exec_mutex is
locked to prevent PTRACE_ATTACH from obsoleting the calculation of
creds that we make.
(a) prepare_exec_creds() is then called to make a copy of the current
task's credentials and prepare it. This copy is then assigned to
bprm->cred.
This renders security_bprm_alloc() and security_bprm_free()
unnecessary, and so they've been removed.
(b) The determination of unsafe execution is now performed immediately
after (a) rather than later on in the code. The result is stored in
bprm->unsafe for future reference.
(c) prepare_binprm() is called, possibly multiple times.
(i) This applies the result of set[ug]id binaries to the new creds
attached to bprm->cred. Personality bit clearance is recorded,
but now deferred on the basis that the exec procedure may yet
fail.
(ii) This then calls the new security_bprm_set_creds(). This should
calculate the new LSM and capability credentials into *bprm->cred.
This folds together security_bprm_set() and parts of
security_bprm_apply_creds() (these two have been removed).
Anything that might fail must be done at this point.
(iii) bprm->cred_prepared is set to 1.
bprm->cred_prepared is 0 on the first pass of the security
calculations, and 1 on all subsequent passes. This allows SELinux
in (ii) to base its calculations only on the initial script and
not on the interpreter.
(d) flush_old_exec() is called to commit the task to execution. This
performs the following steps with regard to credentials:
(i) Clear pdeath_signal and set dumpable on certain circumstances that
may not be covered by commit_creds().
(ii) Clear any bits in current->personality that were deferred from
(c.i).
(e) install_exec_creds() [compute_creds() as was] is called to install the
new credentials. This performs the following steps with regard to
credentials:
(i) Calls security_bprm_committing_creds() to apply any security
requirements, such as flushing unauthorised files in SELinux, that
must be done before the credentials are changed.
This is made up of bits of security_bprm_apply_creds() and
security_bprm_post_apply_creds(), both of which have been removed.
This function is not allowed to fail; anything that might fail
must have been done in (c.ii).
(ii) Calls commit_creds() to apply the new credentials in a single
assignment (more or less). Possibly pdeath_signal and dumpable
should be part of struct creds.
(iii) Unlocks the task's cred_replace_mutex, thus allowing
PTRACE_ATTACH to take place.
(iv) Clears The bprm->cred pointer as the credentials it was holding
are now immutable.
(v) Calls security_bprm_committed_creds() to apply any security
alterations that must be done after the creds have been changed.
SELinux uses this to flush signals and signal handlers.
(f) If an error occurs before (d.i), bprm_free() will call abort_creds()
to destroy the proposed new credentials and will then unlock
cred_replace_mutex. No changes to the credentials will have been
made.
(2) LSM interface.
A number of functions have been changed, added or removed:
(*) security_bprm_alloc(), ->bprm_alloc_security()
(*) security_bprm_free(), ->bprm_free_security()
Removed in favour of preparing new credentials and modifying those.
(*) security_bprm_apply_creds(), ->bprm_apply_creds()
(*) security_bprm_post_apply_creds(), ->bprm_post_apply_creds()
Removed; split between security_bprm_set_creds(),
security_bprm_committing_creds() and security_bprm_committed_creds().
(*) security_bprm_set(), ->bprm_set_security()
Removed; folded into security_bprm_set_creds().
(*) security_bprm_set_creds(), ->bprm_set_creds()
New. The new credentials in bprm->creds should be checked and set up
as appropriate. bprm->cred_prepared is 0 on the first call, 1 on the
second and subsequent calls.
(*) security_bprm_committing_creds(), ->bprm_committing_creds()
(*) security_bprm_committed_creds(), ->bprm_committed_creds()
New. Apply the security effects of the new credentials. This
includes closing unauthorised files in SELinux. This function may not
fail. When the former is called, the creds haven't yet been applied
to the process; when the latter is called, they have.
The former may access bprm->cred, the latter may not.
(3) SELinux.
SELinux has a number of changes, in addition to those to support the LSM
interface changes mentioned above:
(a) The bprm_security_struct struct has been removed in favour of using
the credentials-under-construction approach.
(c) flush_unauthorized_files() now takes a cred pointer and passes it on
to inode_has_perm(), file_has_perm() and dentry_open().
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: James Morris <jmorris@namei.org>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Signed-off-by: James Morris <jmorris@namei.org>
2008-11-13 23:39:24 +00:00
|
|
|
/* Check whether the new SID can inherit resource limits from the old
|
|
|
|
* SID. If not, reset all soft limits to the lower of the current
|
|
|
|
* task's hard limit and the init task's soft limit.
|
|
|
|
*
|
|
|
|
* Note that the setting of hard limits (even to lower them) can be
|
|
|
|
* controlled by the setrlimit check. The inclusion of the init task's
|
|
|
|
* soft limit into the computation is to avoid resetting soft limits
|
|
|
|
* higher than the default soft limit for cases where the default is
|
|
|
|
* lower than the hard limit, e.g. RLIMIT_CORE or RLIMIT_STACK.
|
|
|
|
*/
|
|
|
|
rc = avc_has_perm(new_tsec->osid, new_tsec->sid, SECCLASS_PROCESS,
|
|
|
|
PROCESS__RLIMITINH, NULL);
|
|
|
|
if (rc) {
|
2010-06-23 20:43:32 +00:00
|
|
|
/* protect against do_prlimit() */
|
|
|
|
task_lock(current);
|
CRED: Make execve() take advantage of copy-on-write credentials
Make execve() take advantage of copy-on-write credentials, allowing it to set
up the credentials in advance, and then commit the whole lot after the point
of no return.
This patch and the preceding patches have been tested with the LTP SELinux
testsuite.
This patch makes several logical sets of alteration:
(1) execve().
The credential bits from struct linux_binprm are, for the most part,
replaced with a single credentials pointer (bprm->cred). This means that
all the creds can be calculated in advance and then applied at the point
of no return with no possibility of failure.
I would like to replace bprm->cap_effective with:
cap_isclear(bprm->cap_effective)
but this seems impossible due to special behaviour for processes of pid 1
(they always retain their parent's capability masks where normally they'd
be changed - see cap_bprm_set_creds()).
The following sequence of events now happens:
(a) At the start of do_execve, the current task's cred_exec_mutex is
locked to prevent PTRACE_ATTACH from obsoleting the calculation of
creds that we make.
(a) prepare_exec_creds() is then called to make a copy of the current
task's credentials and prepare it. This copy is then assigned to
bprm->cred.
This renders security_bprm_alloc() and security_bprm_free()
unnecessary, and so they've been removed.
(b) The determination of unsafe execution is now performed immediately
after (a) rather than later on in the code. The result is stored in
bprm->unsafe for future reference.
(c) prepare_binprm() is called, possibly multiple times.
(i) This applies the result of set[ug]id binaries to the new creds
attached to bprm->cred. Personality bit clearance is recorded,
but now deferred on the basis that the exec procedure may yet
fail.
(ii) This then calls the new security_bprm_set_creds(). This should
calculate the new LSM and capability credentials into *bprm->cred.
This folds together security_bprm_set() and parts of
security_bprm_apply_creds() (these two have been removed).
Anything that might fail must be done at this point.
(iii) bprm->cred_prepared is set to 1.
bprm->cred_prepared is 0 on the first pass of the security
calculations, and 1 on all subsequent passes. This allows SELinux
in (ii) to base its calculations only on the initial script and
not on the interpreter.
(d) flush_old_exec() is called to commit the task to execution. This
performs the following steps with regard to credentials:
(i) Clear pdeath_signal and set dumpable on certain circumstances that
may not be covered by commit_creds().
(ii) Clear any bits in current->personality that were deferred from
(c.i).
(e) install_exec_creds() [compute_creds() as was] is called to install the
new credentials. This performs the following steps with regard to
credentials:
(i) Calls security_bprm_committing_creds() to apply any security
requirements, such as flushing unauthorised files in SELinux, that
must be done before the credentials are changed.
This is made up of bits of security_bprm_apply_creds() and
security_bprm_post_apply_creds(), both of which have been removed.
This function is not allowed to fail; anything that might fail
must have been done in (c.ii).
(ii) Calls commit_creds() to apply the new credentials in a single
assignment (more or less). Possibly pdeath_signal and dumpable
should be part of struct creds.
(iii) Unlocks the task's cred_replace_mutex, thus allowing
PTRACE_ATTACH to take place.
(iv) Clears The bprm->cred pointer as the credentials it was holding
are now immutable.
(v) Calls security_bprm_committed_creds() to apply any security
alterations that must be done after the creds have been changed.
SELinux uses this to flush signals and signal handlers.
(f) If an error occurs before (d.i), bprm_free() will call abort_creds()
to destroy the proposed new credentials and will then unlock
cred_replace_mutex. No changes to the credentials will have been
made.
(2) LSM interface.
A number of functions have been changed, added or removed:
(*) security_bprm_alloc(), ->bprm_alloc_security()
(*) security_bprm_free(), ->bprm_free_security()
Removed in favour of preparing new credentials and modifying those.
(*) security_bprm_apply_creds(), ->bprm_apply_creds()
(*) security_bprm_post_apply_creds(), ->bprm_post_apply_creds()
Removed; split between security_bprm_set_creds(),
security_bprm_committing_creds() and security_bprm_committed_creds().
(*) security_bprm_set(), ->bprm_set_security()
Removed; folded into security_bprm_set_creds().
(*) security_bprm_set_creds(), ->bprm_set_creds()
New. The new credentials in bprm->creds should be checked and set up
as appropriate. bprm->cred_prepared is 0 on the first call, 1 on the
second and subsequent calls.
(*) security_bprm_committing_creds(), ->bprm_committing_creds()
(*) security_bprm_committed_creds(), ->bprm_committed_creds()
New. Apply the security effects of the new credentials. This
includes closing unauthorised files in SELinux. This function may not
fail. When the former is called, the creds haven't yet been applied
to the process; when the latter is called, they have.
The former may access bprm->cred, the latter may not.
(3) SELinux.
SELinux has a number of changes, in addition to those to support the LSM
interface changes mentioned above:
(a) The bprm_security_struct struct has been removed in favour of using
the credentials-under-construction approach.
(c) flush_unauthorized_files() now takes a cred pointer and passes it on
to inode_has_perm(), file_has_perm() and dentry_open().
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: James Morris <jmorris@namei.org>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Signed-off-by: James Morris <jmorris@namei.org>
2008-11-13 23:39:24 +00:00
|
|
|
for (i = 0; i < RLIM_NLIMITS; i++) {
|
|
|
|
rlim = current->signal->rlim + i;
|
|
|
|
initrlim = init_task.signal->rlim + i;
|
|
|
|
rlim->rlim_cur = min(rlim->rlim_max, initrlim->rlim_cur);
|
2005-04-16 22:20:36 +00:00
|
|
|
}
|
2010-06-23 20:43:32 +00:00
|
|
|
task_unlock(current);
|
|
|
|
update_rlimit_cpu(current, rlimit(RLIMIT_CPU));
|
2005-04-16 22:20:36 +00:00
|
|
|
}
|
|
|
|
}
|
|
|
|
|
|
|
|
/*
|
CRED: Make execve() take advantage of copy-on-write credentials
Make execve() take advantage of copy-on-write credentials, allowing it to set
up the credentials in advance, and then commit the whole lot after the point
of no return.
This patch and the preceding patches have been tested with the LTP SELinux
testsuite.
This patch makes several logical sets of alteration:
(1) execve().
The credential bits from struct linux_binprm are, for the most part,
replaced with a single credentials pointer (bprm->cred). This means that
all the creds can be calculated in advance and then applied at the point
of no return with no possibility of failure.
I would like to replace bprm->cap_effective with:
cap_isclear(bprm->cap_effective)
but this seems impossible due to special behaviour for processes of pid 1
(they always retain their parent's capability masks where normally they'd
be changed - see cap_bprm_set_creds()).
The following sequence of events now happens:
(a) At the start of do_execve, the current task's cred_exec_mutex is
locked to prevent PTRACE_ATTACH from obsoleting the calculation of
creds that we make.
(a) prepare_exec_creds() is then called to make a copy of the current
task's credentials and prepare it. This copy is then assigned to
bprm->cred.
This renders security_bprm_alloc() and security_bprm_free()
unnecessary, and so they've been removed.
(b) The determination of unsafe execution is now performed immediately
after (a) rather than later on in the code. The result is stored in
bprm->unsafe for future reference.
(c) prepare_binprm() is called, possibly multiple times.
(i) This applies the result of set[ug]id binaries to the new creds
attached to bprm->cred. Personality bit clearance is recorded,
but now deferred on the basis that the exec procedure may yet
fail.
(ii) This then calls the new security_bprm_set_creds(). This should
calculate the new LSM and capability credentials into *bprm->cred.
This folds together security_bprm_set() and parts of
security_bprm_apply_creds() (these two have been removed).
Anything that might fail must be done at this point.
(iii) bprm->cred_prepared is set to 1.
bprm->cred_prepared is 0 on the first pass of the security
calculations, and 1 on all subsequent passes. This allows SELinux
in (ii) to base its calculations only on the initial script and
not on the interpreter.
(d) flush_old_exec() is called to commit the task to execution. This
performs the following steps with regard to credentials:
(i) Clear pdeath_signal and set dumpable on certain circumstances that
may not be covered by commit_creds().
(ii) Clear any bits in current->personality that were deferred from
(c.i).
(e) install_exec_creds() [compute_creds() as was] is called to install the
new credentials. This performs the following steps with regard to
credentials:
(i) Calls security_bprm_committing_creds() to apply any security
requirements, such as flushing unauthorised files in SELinux, that
must be done before the credentials are changed.
This is made up of bits of security_bprm_apply_creds() and
security_bprm_post_apply_creds(), both of which have been removed.
This function is not allowed to fail; anything that might fail
must have been done in (c.ii).
(ii) Calls commit_creds() to apply the new credentials in a single
assignment (more or less). Possibly pdeath_signal and dumpable
should be part of struct creds.
(iii) Unlocks the task's cred_replace_mutex, thus allowing
PTRACE_ATTACH to take place.
(iv) Clears The bprm->cred pointer as the credentials it was holding
are now immutable.
(v) Calls security_bprm_committed_creds() to apply any security
alterations that must be done after the creds have been changed.
SELinux uses this to flush signals and signal handlers.
(f) If an error occurs before (d.i), bprm_free() will call abort_creds()
to destroy the proposed new credentials and will then unlock
cred_replace_mutex. No changes to the credentials will have been
made.
(2) LSM interface.
A number of functions have been changed, added or removed:
(*) security_bprm_alloc(), ->bprm_alloc_security()
(*) security_bprm_free(), ->bprm_free_security()
Removed in favour of preparing new credentials and modifying those.
(*) security_bprm_apply_creds(), ->bprm_apply_creds()
(*) security_bprm_post_apply_creds(), ->bprm_post_apply_creds()
Removed; split between security_bprm_set_creds(),
security_bprm_committing_creds() and security_bprm_committed_creds().
(*) security_bprm_set(), ->bprm_set_security()
Removed; folded into security_bprm_set_creds().
(*) security_bprm_set_creds(), ->bprm_set_creds()
New. The new credentials in bprm->creds should be checked and set up
as appropriate. bprm->cred_prepared is 0 on the first call, 1 on the
second and subsequent calls.
(*) security_bprm_committing_creds(), ->bprm_committing_creds()
(*) security_bprm_committed_creds(), ->bprm_committed_creds()
New. Apply the security effects of the new credentials. This
includes closing unauthorised files in SELinux. This function may not
fail. When the former is called, the creds haven't yet been applied
to the process; when the latter is called, they have.
The former may access bprm->cred, the latter may not.
(3) SELinux.
SELinux has a number of changes, in addition to those to support the LSM
interface changes mentioned above:
(a) The bprm_security_struct struct has been removed in favour of using
the credentials-under-construction approach.
(c) flush_unauthorized_files() now takes a cred pointer and passes it on
to inode_has_perm(), file_has_perm() and dentry_open().
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: James Morris <jmorris@namei.org>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Signed-off-by: James Morris <jmorris@namei.org>
2008-11-13 23:39:24 +00:00
|
|
|
* Clean up the process immediately after the installation of new credentials
|
|
|
|
* due to exec
|
2005-04-16 22:20:36 +00:00
|
|
|
*/
|
CRED: Make execve() take advantage of copy-on-write credentials
Make execve() take advantage of copy-on-write credentials, allowing it to set
up the credentials in advance, and then commit the whole lot after the point
of no return.
This patch and the preceding patches have been tested with the LTP SELinux
testsuite.
This patch makes several logical sets of alteration:
(1) execve().
The credential bits from struct linux_binprm are, for the most part,
replaced with a single credentials pointer (bprm->cred). This means that
all the creds can be calculated in advance and then applied at the point
of no return with no possibility of failure.
I would like to replace bprm->cap_effective with:
cap_isclear(bprm->cap_effective)
but this seems impossible due to special behaviour for processes of pid 1
(they always retain their parent's capability masks where normally they'd
be changed - see cap_bprm_set_creds()).
The following sequence of events now happens:
(a) At the start of do_execve, the current task's cred_exec_mutex is
locked to prevent PTRACE_ATTACH from obsoleting the calculation of
creds that we make.
(a) prepare_exec_creds() is then called to make a copy of the current
task's credentials and prepare it. This copy is then assigned to
bprm->cred.
This renders security_bprm_alloc() and security_bprm_free()
unnecessary, and so they've been removed.
(b) The determination of unsafe execution is now performed immediately
after (a) rather than later on in the code. The result is stored in
bprm->unsafe for future reference.
(c) prepare_binprm() is called, possibly multiple times.
(i) This applies the result of set[ug]id binaries to the new creds
attached to bprm->cred. Personality bit clearance is recorded,
but now deferred on the basis that the exec procedure may yet
fail.
(ii) This then calls the new security_bprm_set_creds(). This should
calculate the new LSM and capability credentials into *bprm->cred.
This folds together security_bprm_set() and parts of
security_bprm_apply_creds() (these two have been removed).
Anything that might fail must be done at this point.
(iii) bprm->cred_prepared is set to 1.
bprm->cred_prepared is 0 on the first pass of the security
calculations, and 1 on all subsequent passes. This allows SELinux
in (ii) to base its calculations only on the initial script and
not on the interpreter.
(d) flush_old_exec() is called to commit the task to execution. This
performs the following steps with regard to credentials:
(i) Clear pdeath_signal and set dumpable on certain circumstances that
may not be covered by commit_creds().
(ii) Clear any bits in current->personality that were deferred from
(c.i).
(e) install_exec_creds() [compute_creds() as was] is called to install the
new credentials. This performs the following steps with regard to
credentials:
(i) Calls security_bprm_committing_creds() to apply any security
requirements, such as flushing unauthorised files in SELinux, that
must be done before the credentials are changed.
This is made up of bits of security_bprm_apply_creds() and
security_bprm_post_apply_creds(), both of which have been removed.
This function is not allowed to fail; anything that might fail
must have been done in (c.ii).
(ii) Calls commit_creds() to apply the new credentials in a single
assignment (more or less). Possibly pdeath_signal and dumpable
should be part of struct creds.
(iii) Unlocks the task's cred_replace_mutex, thus allowing
PTRACE_ATTACH to take place.
(iv) Clears The bprm->cred pointer as the credentials it was holding
are now immutable.
(v) Calls security_bprm_committed_creds() to apply any security
alterations that must be done after the creds have been changed.
SELinux uses this to flush signals and signal handlers.
(f) If an error occurs before (d.i), bprm_free() will call abort_creds()
to destroy the proposed new credentials and will then unlock
cred_replace_mutex. No changes to the credentials will have been
made.
(2) LSM interface.
A number of functions have been changed, added or removed:
(*) security_bprm_alloc(), ->bprm_alloc_security()
(*) security_bprm_free(), ->bprm_free_security()
Removed in favour of preparing new credentials and modifying those.
(*) security_bprm_apply_creds(), ->bprm_apply_creds()
(*) security_bprm_post_apply_creds(), ->bprm_post_apply_creds()
Removed; split between security_bprm_set_creds(),
security_bprm_committing_creds() and security_bprm_committed_creds().
(*) security_bprm_set(), ->bprm_set_security()
Removed; folded into security_bprm_set_creds().
(*) security_bprm_set_creds(), ->bprm_set_creds()
New. The new credentials in bprm->creds should be checked and set up
as appropriate. bprm->cred_prepared is 0 on the first call, 1 on the
second and subsequent calls.
(*) security_bprm_committing_creds(), ->bprm_committing_creds()
(*) security_bprm_committed_creds(), ->bprm_committed_creds()
New. Apply the security effects of the new credentials. This
includes closing unauthorised files in SELinux. This function may not
fail. When the former is called, the creds haven't yet been applied
to the process; when the latter is called, they have.
The former may access bprm->cred, the latter may not.
(3) SELinux.
SELinux has a number of changes, in addition to those to support the LSM
interface changes mentioned above:
(a) The bprm_security_struct struct has been removed in favour of using
the credentials-under-construction approach.
(c) flush_unauthorized_files() now takes a cred pointer and passes it on
to inode_has_perm(), file_has_perm() and dentry_open().
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: James Morris <jmorris@namei.org>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Signed-off-by: James Morris <jmorris@namei.org>
2008-11-13 23:39:24 +00:00
|
|
|
static void selinux_bprm_committed_creds(struct linux_binprm *bprm)
|
2005-04-16 22:20:36 +00:00
|
|
|
{
|
CRED: Make execve() take advantage of copy-on-write credentials
Make execve() take advantage of copy-on-write credentials, allowing it to set
up the credentials in advance, and then commit the whole lot after the point
of no return.
This patch and the preceding patches have been tested with the LTP SELinux
testsuite.
This patch makes several logical sets of alteration:
(1) execve().
The credential bits from struct linux_binprm are, for the most part,
replaced with a single credentials pointer (bprm->cred). This means that
all the creds can be calculated in advance and then applied at the point
of no return with no possibility of failure.
I would like to replace bprm->cap_effective with:
cap_isclear(bprm->cap_effective)
but this seems impossible due to special behaviour for processes of pid 1
(they always retain their parent's capability masks where normally they'd
be changed - see cap_bprm_set_creds()).
The following sequence of events now happens:
(a) At the start of do_execve, the current task's cred_exec_mutex is
locked to prevent PTRACE_ATTACH from obsoleting the calculation of
creds that we make.
(a) prepare_exec_creds() is then called to make a copy of the current
task's credentials and prepare it. This copy is then assigned to
bprm->cred.
This renders security_bprm_alloc() and security_bprm_free()
unnecessary, and so they've been removed.
(b) The determination of unsafe execution is now performed immediately
after (a) rather than later on in the code. The result is stored in
bprm->unsafe for future reference.
(c) prepare_binprm() is called, possibly multiple times.
(i) This applies the result of set[ug]id binaries to the new creds
attached to bprm->cred. Personality bit clearance is recorded,
but now deferred on the basis that the exec procedure may yet
fail.
(ii) This then calls the new security_bprm_set_creds(). This should
calculate the new LSM and capability credentials into *bprm->cred.
This folds together security_bprm_set() and parts of
security_bprm_apply_creds() (these two have been removed).
Anything that might fail must be done at this point.
(iii) bprm->cred_prepared is set to 1.
bprm->cred_prepared is 0 on the first pass of the security
calculations, and 1 on all subsequent passes. This allows SELinux
in (ii) to base its calculations only on the initial script and
not on the interpreter.
(d) flush_old_exec() is called to commit the task to execution. This
performs the following steps with regard to credentials:
(i) Clear pdeath_signal and set dumpable on certain circumstances that
may not be covered by commit_creds().
(ii) Clear any bits in current->personality that were deferred from
(c.i).
(e) install_exec_creds() [compute_creds() as was] is called to install the
new credentials. This performs the following steps with regard to
credentials:
(i) Calls security_bprm_committing_creds() to apply any security
requirements, such as flushing unauthorised files in SELinux, that
must be done before the credentials are changed.
This is made up of bits of security_bprm_apply_creds() and
security_bprm_post_apply_creds(), both of which have been removed.
This function is not allowed to fail; anything that might fail
must have been done in (c.ii).
(ii) Calls commit_creds() to apply the new credentials in a single
assignment (more or less). Possibly pdeath_signal and dumpable
should be part of struct creds.
(iii) Unlocks the task's cred_replace_mutex, thus allowing
PTRACE_ATTACH to take place.
(iv) Clears The bprm->cred pointer as the credentials it was holding
are now immutable.
(v) Calls security_bprm_committed_creds() to apply any security
alterations that must be done after the creds have been changed.
SELinux uses this to flush signals and signal handlers.
(f) If an error occurs before (d.i), bprm_free() will call abort_creds()
to destroy the proposed new credentials and will then unlock
cred_replace_mutex. No changes to the credentials will have been
made.
(2) LSM interface.
A number of functions have been changed, added or removed:
(*) security_bprm_alloc(), ->bprm_alloc_security()
(*) security_bprm_free(), ->bprm_free_security()
Removed in favour of preparing new credentials and modifying those.
(*) security_bprm_apply_creds(), ->bprm_apply_creds()
(*) security_bprm_post_apply_creds(), ->bprm_post_apply_creds()
Removed; split between security_bprm_set_creds(),
security_bprm_committing_creds() and security_bprm_committed_creds().
(*) security_bprm_set(), ->bprm_set_security()
Removed; folded into security_bprm_set_creds().
(*) security_bprm_set_creds(), ->bprm_set_creds()
New. The new credentials in bprm->creds should be checked and set up
as appropriate. bprm->cred_prepared is 0 on the first call, 1 on the
second and subsequent calls.
(*) security_bprm_committing_creds(), ->bprm_committing_creds()
(*) security_bprm_committed_creds(), ->bprm_committed_creds()
New. Apply the security effects of the new credentials. This
includes closing unauthorised files in SELinux. This function may not
fail. When the former is called, the creds haven't yet been applied
to the process; when the latter is called, they have.
The former may access bprm->cred, the latter may not.
(3) SELinux.
SELinux has a number of changes, in addition to those to support the LSM
interface changes mentioned above:
(a) The bprm_security_struct struct has been removed in favour of using
the credentials-under-construction approach.
(c) flush_unauthorized_files() now takes a cred pointer and passes it on
to inode_has_perm(), file_has_perm() and dentry_open().
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: James Morris <jmorris@namei.org>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Signed-off-by: James Morris <jmorris@namei.org>
2008-11-13 23:39:24 +00:00
|
|
|
const struct task_security_struct *tsec = current_security();
|
2005-04-16 22:20:36 +00:00
|
|
|
struct itimerval itimer;
|
CRED: Make execve() take advantage of copy-on-write credentials
Make execve() take advantage of copy-on-write credentials, allowing it to set
up the credentials in advance, and then commit the whole lot after the point
of no return.
This patch and the preceding patches have been tested with the LTP SELinux
testsuite.
This patch makes several logical sets of alteration:
(1) execve().
The credential bits from struct linux_binprm are, for the most part,
replaced with a single credentials pointer (bprm->cred). This means that
all the creds can be calculated in advance and then applied at the point
of no return with no possibility of failure.
I would like to replace bprm->cap_effective with:
cap_isclear(bprm->cap_effective)
but this seems impossible due to special behaviour for processes of pid 1
(they always retain their parent's capability masks where normally they'd
be changed - see cap_bprm_set_creds()).
The following sequence of events now happens:
(a) At the start of do_execve, the current task's cred_exec_mutex is
locked to prevent PTRACE_ATTACH from obsoleting the calculation of
creds that we make.
(a) prepare_exec_creds() is then called to make a copy of the current
task's credentials and prepare it. This copy is then assigned to
bprm->cred.
This renders security_bprm_alloc() and security_bprm_free()
unnecessary, and so they've been removed.
(b) The determination of unsafe execution is now performed immediately
after (a) rather than later on in the code. The result is stored in
bprm->unsafe for future reference.
(c) prepare_binprm() is called, possibly multiple times.
(i) This applies the result of set[ug]id binaries to the new creds
attached to bprm->cred. Personality bit clearance is recorded,
but now deferred on the basis that the exec procedure may yet
fail.
(ii) This then calls the new security_bprm_set_creds(). This should
calculate the new LSM and capability credentials into *bprm->cred.
This folds together security_bprm_set() and parts of
security_bprm_apply_creds() (these two have been removed).
Anything that might fail must be done at this point.
(iii) bprm->cred_prepared is set to 1.
bprm->cred_prepared is 0 on the first pass of the security
calculations, and 1 on all subsequent passes. This allows SELinux
in (ii) to base its calculations only on the initial script and
not on the interpreter.
(d) flush_old_exec() is called to commit the task to execution. This
performs the following steps with regard to credentials:
(i) Clear pdeath_signal and set dumpable on certain circumstances that
may not be covered by commit_creds().
(ii) Clear any bits in current->personality that were deferred from
(c.i).
(e) install_exec_creds() [compute_creds() as was] is called to install the
new credentials. This performs the following steps with regard to
credentials:
(i) Calls security_bprm_committing_creds() to apply any security
requirements, such as flushing unauthorised files in SELinux, that
must be done before the credentials are changed.
This is made up of bits of security_bprm_apply_creds() and
security_bprm_post_apply_creds(), both of which have been removed.
This function is not allowed to fail; anything that might fail
must have been done in (c.ii).
(ii) Calls commit_creds() to apply the new credentials in a single
assignment (more or less). Possibly pdeath_signal and dumpable
should be part of struct creds.
(iii) Unlocks the task's cred_replace_mutex, thus allowing
PTRACE_ATTACH to take place.
(iv) Clears The bprm->cred pointer as the credentials it was holding
are now immutable.
(v) Calls security_bprm_committed_creds() to apply any security
alterations that must be done after the creds have been changed.
SELinux uses this to flush signals and signal handlers.
(f) If an error occurs before (d.i), bprm_free() will call abort_creds()
to destroy the proposed new credentials and will then unlock
cred_replace_mutex. No changes to the credentials will have been
made.
(2) LSM interface.
A number of functions have been changed, added or removed:
(*) security_bprm_alloc(), ->bprm_alloc_security()
(*) security_bprm_free(), ->bprm_free_security()
Removed in favour of preparing new credentials and modifying those.
(*) security_bprm_apply_creds(), ->bprm_apply_creds()
(*) security_bprm_post_apply_creds(), ->bprm_post_apply_creds()
Removed; split between security_bprm_set_creds(),
security_bprm_committing_creds() and security_bprm_committed_creds().
(*) security_bprm_set(), ->bprm_set_security()
Removed; folded into security_bprm_set_creds().
(*) security_bprm_set_creds(), ->bprm_set_creds()
New. The new credentials in bprm->creds should be checked and set up
as appropriate. bprm->cred_prepared is 0 on the first call, 1 on the
second and subsequent calls.
(*) security_bprm_committing_creds(), ->bprm_committing_creds()
(*) security_bprm_committed_creds(), ->bprm_committed_creds()
New. Apply the security effects of the new credentials. This
includes closing unauthorised files in SELinux. This function may not
fail. When the former is called, the creds haven't yet been applied
to the process; when the latter is called, they have.
The former may access bprm->cred, the latter may not.
(3) SELinux.
SELinux has a number of changes, in addition to those to support the LSM
interface changes mentioned above:
(a) The bprm_security_struct struct has been removed in favour of using
the credentials-under-construction approach.
(c) flush_unauthorized_files() now takes a cred pointer and passes it on
to inode_has_perm(), file_has_perm() and dentry_open().
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: James Morris <jmorris@namei.org>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Signed-off-by: James Morris <jmorris@namei.org>
2008-11-13 23:39:24 +00:00
|
|
|
u32 osid, sid;
|
2005-04-16 22:20:36 +00:00
|
|
|
int rc, i;
|
|
|
|
|
CRED: Make execve() take advantage of copy-on-write credentials
Make execve() take advantage of copy-on-write credentials, allowing it to set
up the credentials in advance, and then commit the whole lot after the point
of no return.
This patch and the preceding patches have been tested with the LTP SELinux
testsuite.
This patch makes several logical sets of alteration:
(1) execve().
The credential bits from struct linux_binprm are, for the most part,
replaced with a single credentials pointer (bprm->cred). This means that
all the creds can be calculated in advance and then applied at the point
of no return with no possibility of failure.
I would like to replace bprm->cap_effective with:
cap_isclear(bprm->cap_effective)
but this seems impossible due to special behaviour for processes of pid 1
(they always retain their parent's capability masks where normally they'd
be changed - see cap_bprm_set_creds()).
The following sequence of events now happens:
(a) At the start of do_execve, the current task's cred_exec_mutex is
locked to prevent PTRACE_ATTACH from obsoleting the calculation of
creds that we make.
(a) prepare_exec_creds() is then called to make a copy of the current
task's credentials and prepare it. This copy is then assigned to
bprm->cred.
This renders security_bprm_alloc() and security_bprm_free()
unnecessary, and so they've been removed.
(b) The determination of unsafe execution is now performed immediately
after (a) rather than later on in the code. The result is stored in
bprm->unsafe for future reference.
(c) prepare_binprm() is called, possibly multiple times.
(i) This applies the result of set[ug]id binaries to the new creds
attached to bprm->cred. Personality bit clearance is recorded,
but now deferred on the basis that the exec procedure may yet
fail.
(ii) This then calls the new security_bprm_set_creds(). This should
calculate the new LSM and capability credentials into *bprm->cred.
This folds together security_bprm_set() and parts of
security_bprm_apply_creds() (these two have been removed).
Anything that might fail must be done at this point.
(iii) bprm->cred_prepared is set to 1.
bprm->cred_prepared is 0 on the first pass of the security
calculations, and 1 on all subsequent passes. This allows SELinux
in (ii) to base its calculations only on the initial script and
not on the interpreter.
(d) flush_old_exec() is called to commit the task to execution. This
performs the following steps with regard to credentials:
(i) Clear pdeath_signal and set dumpable on certain circumstances that
may not be covered by commit_creds().
(ii) Clear any bits in current->personality that were deferred from
(c.i).
(e) install_exec_creds() [compute_creds() as was] is called to install the
new credentials. This performs the following steps with regard to
credentials:
(i) Calls security_bprm_committing_creds() to apply any security
requirements, such as flushing unauthorised files in SELinux, that
must be done before the credentials are changed.
This is made up of bits of security_bprm_apply_creds() and
security_bprm_post_apply_creds(), both of which have been removed.
This function is not allowed to fail; anything that might fail
must have been done in (c.ii).
(ii) Calls commit_creds() to apply the new credentials in a single
assignment (more or less). Possibly pdeath_signal and dumpable
should be part of struct creds.
(iii) Unlocks the task's cred_replace_mutex, thus allowing
PTRACE_ATTACH to take place.
(iv) Clears The bprm->cred pointer as the credentials it was holding
are now immutable.
(v) Calls security_bprm_committed_creds() to apply any security
alterations that must be done after the creds have been changed.
SELinux uses this to flush signals and signal handlers.
(f) If an error occurs before (d.i), bprm_free() will call abort_creds()
to destroy the proposed new credentials and will then unlock
cred_replace_mutex. No changes to the credentials will have been
made.
(2) LSM interface.
A number of functions have been changed, added or removed:
(*) security_bprm_alloc(), ->bprm_alloc_security()
(*) security_bprm_free(), ->bprm_free_security()
Removed in favour of preparing new credentials and modifying those.
(*) security_bprm_apply_creds(), ->bprm_apply_creds()
(*) security_bprm_post_apply_creds(), ->bprm_post_apply_creds()
Removed; split between security_bprm_set_creds(),
security_bprm_committing_creds() and security_bprm_committed_creds().
(*) security_bprm_set(), ->bprm_set_security()
Removed; folded into security_bprm_set_creds().
(*) security_bprm_set_creds(), ->bprm_set_creds()
New. The new credentials in bprm->creds should be checked and set up
as appropriate. bprm->cred_prepared is 0 on the first call, 1 on the
second and subsequent calls.
(*) security_bprm_committing_creds(), ->bprm_committing_creds()
(*) security_bprm_committed_creds(), ->bprm_committed_creds()
New. Apply the security effects of the new credentials. This
includes closing unauthorised files in SELinux. This function may not
fail. When the former is called, the creds haven't yet been applied
to the process; when the latter is called, they have.
The former may access bprm->cred, the latter may not.
(3) SELinux.
SELinux has a number of changes, in addition to those to support the LSM
interface changes mentioned above:
(a) The bprm_security_struct struct has been removed in favour of using
the credentials-under-construction approach.
(c) flush_unauthorized_files() now takes a cred pointer and passes it on
to inode_has_perm(), file_has_perm() and dentry_open().
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: James Morris <jmorris@namei.org>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Signed-off-by: James Morris <jmorris@namei.org>
2008-11-13 23:39:24 +00:00
|
|
|
osid = tsec->osid;
|
|
|
|
sid = tsec->sid;
|
|
|
|
|
|
|
|
if (sid == osid)
|
2005-04-16 22:20:36 +00:00
|
|
|
return;
|
|
|
|
|
CRED: Make execve() take advantage of copy-on-write credentials
Make execve() take advantage of copy-on-write credentials, allowing it to set
up the credentials in advance, and then commit the whole lot after the point
of no return.
This patch and the preceding patches have been tested with the LTP SELinux
testsuite.
This patch makes several logical sets of alteration:
(1) execve().
The credential bits from struct linux_binprm are, for the most part,
replaced with a single credentials pointer (bprm->cred). This means that
all the creds can be calculated in advance and then applied at the point
of no return with no possibility of failure.
I would like to replace bprm->cap_effective with:
cap_isclear(bprm->cap_effective)
but this seems impossible due to special behaviour for processes of pid 1
(they always retain their parent's capability masks where normally they'd
be changed - see cap_bprm_set_creds()).
The following sequence of events now happens:
(a) At the start of do_execve, the current task's cred_exec_mutex is
locked to prevent PTRACE_ATTACH from obsoleting the calculation of
creds that we make.
(a) prepare_exec_creds() is then called to make a copy of the current
task's credentials and prepare it. This copy is then assigned to
bprm->cred.
This renders security_bprm_alloc() and security_bprm_free()
unnecessary, and so they've been removed.
(b) The determination of unsafe execution is now performed immediately
after (a) rather than later on in the code. The result is stored in
bprm->unsafe for future reference.
(c) prepare_binprm() is called, possibly multiple times.
(i) This applies the result of set[ug]id binaries to the new creds
attached to bprm->cred. Personality bit clearance is recorded,
but now deferred on the basis that the exec procedure may yet
fail.
(ii) This then calls the new security_bprm_set_creds(). This should
calculate the new LSM and capability credentials into *bprm->cred.
This folds together security_bprm_set() and parts of
security_bprm_apply_creds() (these two have been removed).
Anything that might fail must be done at this point.
(iii) bprm->cred_prepared is set to 1.
bprm->cred_prepared is 0 on the first pass of the security
calculations, and 1 on all subsequent passes. This allows SELinux
in (ii) to base its calculations only on the initial script and
not on the interpreter.
(d) flush_old_exec() is called to commit the task to execution. This
performs the following steps with regard to credentials:
(i) Clear pdeath_signal and set dumpable on certain circumstances that
may not be covered by commit_creds().
(ii) Clear any bits in current->personality that were deferred from
(c.i).
(e) install_exec_creds() [compute_creds() as was] is called to install the
new credentials. This performs the following steps with regard to
credentials:
(i) Calls security_bprm_committing_creds() to apply any security
requirements, such as flushing unauthorised files in SELinux, that
must be done before the credentials are changed.
This is made up of bits of security_bprm_apply_creds() and
security_bprm_post_apply_creds(), both of which have been removed.
This function is not allowed to fail; anything that might fail
must have been done in (c.ii).
(ii) Calls commit_creds() to apply the new credentials in a single
assignment (more or less). Possibly pdeath_signal and dumpable
should be part of struct creds.
(iii) Unlocks the task's cred_replace_mutex, thus allowing
PTRACE_ATTACH to take place.
(iv) Clears The bprm->cred pointer as the credentials it was holding
are now immutable.
(v) Calls security_bprm_committed_creds() to apply any security
alterations that must be done after the creds have been changed.
SELinux uses this to flush signals and signal handlers.
(f) If an error occurs before (d.i), bprm_free() will call abort_creds()
to destroy the proposed new credentials and will then unlock
cred_replace_mutex. No changes to the credentials will have been
made.
(2) LSM interface.
A number of functions have been changed, added or removed:
(*) security_bprm_alloc(), ->bprm_alloc_security()
(*) security_bprm_free(), ->bprm_free_security()
Removed in favour of preparing new credentials and modifying those.
(*) security_bprm_apply_creds(), ->bprm_apply_creds()
(*) security_bprm_post_apply_creds(), ->bprm_post_apply_creds()
Removed; split between security_bprm_set_creds(),
security_bprm_committing_creds() and security_bprm_committed_creds().
(*) security_bprm_set(), ->bprm_set_security()
Removed; folded into security_bprm_set_creds().
(*) security_bprm_set_creds(), ->bprm_set_creds()
New. The new credentials in bprm->creds should be checked and set up
as appropriate. bprm->cred_prepared is 0 on the first call, 1 on the
second and subsequent calls.
(*) security_bprm_committing_creds(), ->bprm_committing_creds()
(*) security_bprm_committed_creds(), ->bprm_committed_creds()
New. Apply the security effects of the new credentials. This
includes closing unauthorised files in SELinux. This function may not
fail. When the former is called, the creds haven't yet been applied
to the process; when the latter is called, they have.
The former may access bprm->cred, the latter may not.
(3) SELinux.
SELinux has a number of changes, in addition to those to support the LSM
interface changes mentioned above:
(a) The bprm_security_struct struct has been removed in favour of using
the credentials-under-construction approach.
(c) flush_unauthorized_files() now takes a cred pointer and passes it on
to inode_has_perm(), file_has_perm() and dentry_open().
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: James Morris <jmorris@namei.org>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Signed-off-by: James Morris <jmorris@namei.org>
2008-11-13 23:39:24 +00:00
|
|
|
/* Check whether the new SID can inherit signal state from the old SID.
|
|
|
|
* If not, clear itimers to avoid subsequent signal generation and
|
|
|
|
* flush and unblock signals.
|
|
|
|
*
|
|
|
|
* This must occur _after_ the task SID has been updated so that any
|
|
|
|
* kill done after the flush will be checked against the new SID.
|
|
|
|
*/
|
|
|
|
rc = avc_has_perm(osid, sid, SECCLASS_PROCESS, PROCESS__SIGINH, NULL);
|
2005-04-16 22:20:36 +00:00
|
|
|
if (rc) {
|
|
|
|
memset(&itimer, 0, sizeof itimer);
|
|
|
|
for (i = 0; i < 3; i++)
|
|
|
|
do_setitimer(i, &itimer, NULL);
|
|
|
|
spin_lock_irq(¤t->sighand->siglock);
|
2009-04-29 12:45:05 +00:00
|
|
|
if (!(current->signal->flags & SIGNAL_GROUP_EXIT)) {
|
|
|
|
__flush_signals(current);
|
|
|
|
flush_signal_handlers(current, 1);
|
|
|
|
sigemptyset(¤t->blocked);
|
|
|
|
}
|
2005-04-16 22:20:36 +00:00
|
|
|
spin_unlock_irq(¤t->sighand->siglock);
|
|
|
|
}
|
|
|
|
|
CRED: Make execve() take advantage of copy-on-write credentials
Make execve() take advantage of copy-on-write credentials, allowing it to set
up the credentials in advance, and then commit the whole lot after the point
of no return.
This patch and the preceding patches have been tested with the LTP SELinux
testsuite.
This patch makes several logical sets of alteration:
(1) execve().
The credential bits from struct linux_binprm are, for the most part,
replaced with a single credentials pointer (bprm->cred). This means that
all the creds can be calculated in advance and then applied at the point
of no return with no possibility of failure.
I would like to replace bprm->cap_effective with:
cap_isclear(bprm->cap_effective)
but this seems impossible due to special behaviour for processes of pid 1
(they always retain their parent's capability masks where normally they'd
be changed - see cap_bprm_set_creds()).
The following sequence of events now happens:
(a) At the start of do_execve, the current task's cred_exec_mutex is
locked to prevent PTRACE_ATTACH from obsoleting the calculation of
creds that we make.
(a) prepare_exec_creds() is then called to make a copy of the current
task's credentials and prepare it. This copy is then assigned to
bprm->cred.
This renders security_bprm_alloc() and security_bprm_free()
unnecessary, and so they've been removed.
(b) The determination of unsafe execution is now performed immediately
after (a) rather than later on in the code. The result is stored in
bprm->unsafe for future reference.
(c) prepare_binprm() is called, possibly multiple times.
(i) This applies the result of set[ug]id binaries to the new creds
attached to bprm->cred. Personality bit clearance is recorded,
but now deferred on the basis that the exec procedure may yet
fail.
(ii) This then calls the new security_bprm_set_creds(). This should
calculate the new LSM and capability credentials into *bprm->cred.
This folds together security_bprm_set() and parts of
security_bprm_apply_creds() (these two have been removed).
Anything that might fail must be done at this point.
(iii) bprm->cred_prepared is set to 1.
bprm->cred_prepared is 0 on the first pass of the security
calculations, and 1 on all subsequent passes. This allows SELinux
in (ii) to base its calculations only on the initial script and
not on the interpreter.
(d) flush_old_exec() is called to commit the task to execution. This
performs the following steps with regard to credentials:
(i) Clear pdeath_signal and set dumpable on certain circumstances that
may not be covered by commit_creds().
(ii) Clear any bits in current->personality that were deferred from
(c.i).
(e) install_exec_creds() [compute_creds() as was] is called to install the
new credentials. This performs the following steps with regard to
credentials:
(i) Calls security_bprm_committing_creds() to apply any security
requirements, such as flushing unauthorised files in SELinux, that
must be done before the credentials are changed.
This is made up of bits of security_bprm_apply_creds() and
security_bprm_post_apply_creds(), both of which have been removed.
This function is not allowed to fail; anything that might fail
must have been done in (c.ii).
(ii) Calls commit_creds() to apply the new credentials in a single
assignment (more or less). Possibly pdeath_signal and dumpable
should be part of struct creds.
(iii) Unlocks the task's cred_replace_mutex, thus allowing
PTRACE_ATTACH to take place.
(iv) Clears The bprm->cred pointer as the credentials it was holding
are now immutable.
(v) Calls security_bprm_committed_creds() to apply any security
alterations that must be done after the creds have been changed.
SELinux uses this to flush signals and signal handlers.
(f) If an error occurs before (d.i), bprm_free() will call abort_creds()
to destroy the proposed new credentials and will then unlock
cred_replace_mutex. No changes to the credentials will have been
made.
(2) LSM interface.
A number of functions have been changed, added or removed:
(*) security_bprm_alloc(), ->bprm_alloc_security()
(*) security_bprm_free(), ->bprm_free_security()
Removed in favour of preparing new credentials and modifying those.
(*) security_bprm_apply_creds(), ->bprm_apply_creds()
(*) security_bprm_post_apply_creds(), ->bprm_post_apply_creds()
Removed; split between security_bprm_set_creds(),
security_bprm_committing_creds() and security_bprm_committed_creds().
(*) security_bprm_set(), ->bprm_set_security()
Removed; folded into security_bprm_set_creds().
(*) security_bprm_set_creds(), ->bprm_set_creds()
New. The new credentials in bprm->creds should be checked and set up
as appropriate. bprm->cred_prepared is 0 on the first call, 1 on the
second and subsequent calls.
(*) security_bprm_committing_creds(), ->bprm_committing_creds()
(*) security_bprm_committed_creds(), ->bprm_committed_creds()
New. Apply the security effects of the new credentials. This
includes closing unauthorised files in SELinux. This function may not
fail. When the former is called, the creds haven't yet been applied
to the process; when the latter is called, they have.
The former may access bprm->cred, the latter may not.
(3) SELinux.
SELinux has a number of changes, in addition to those to support the LSM
interface changes mentioned above:
(a) The bprm_security_struct struct has been removed in favour of using
the credentials-under-construction approach.
(c) flush_unauthorized_files() now takes a cred pointer and passes it on
to inode_has_perm(), file_has_perm() and dentry_open().
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: James Morris <jmorris@namei.org>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Signed-off-by: James Morris <jmorris@namei.org>
2008-11-13 23:39:24 +00:00
|
|
|
/* Wake up the parent if it is waiting so that it can recheck
|
|
|
|
* wait permission to the new task SID. */
|
2009-04-29 14:02:24 +00:00
|
|
|
read_lock(&tasklist_lock);
|
2009-09-23 22:56:46 +00:00
|
|
|
__wake_up_parent(current, current->real_parent);
|
2009-04-29 14:02:24 +00:00
|
|
|
read_unlock(&tasklist_lock);
|
2005-04-16 22:20:36 +00:00
|
|
|
}
|
|
|
|
|
|
|
|
/* superblock security operations */
|
|
|
|
|
|
|
|
static int selinux_sb_alloc_security(struct super_block *sb)
|
|
|
|
{
|
|
|
|
return superblock_alloc_security(sb);
|
|
|
|
}
|
|
|
|
|
|
|
|
static void selinux_sb_free_security(struct super_block *sb)
|
|
|
|
{
|
|
|
|
superblock_free_security(sb);
|
|
|
|
}
|
|
|
|
|
|
|
|
static inline int match_prefix(char *prefix, int plen, char *option, int olen)
|
|
|
|
{
|
|
|
|
if (plen > olen)
|
|
|
|
return 0;
|
|
|
|
|
|
|
|
return !memcmp(prefix, option, plen);
|
|
|
|
}
|
|
|
|
|
|
|
|
static inline int selinux_option(char *option, int len)
|
|
|
|
{
|
2008-04-01 17:24:09 +00:00
|
|
|
return (match_prefix(CONTEXT_STR, sizeof(CONTEXT_STR)-1, option, len) ||
|
|
|
|
match_prefix(FSCONTEXT_STR, sizeof(FSCONTEXT_STR)-1, option, len) ||
|
|
|
|
match_prefix(DEFCONTEXT_STR, sizeof(DEFCONTEXT_STR)-1, option, len) ||
|
2009-01-16 14:22:03 +00:00
|
|
|
match_prefix(ROOTCONTEXT_STR, sizeof(ROOTCONTEXT_STR)-1, option, len) ||
|
|
|
|
match_prefix(LABELSUPP_STR, sizeof(LABELSUPP_STR)-1, option, len));
|
2005-04-16 22:20:36 +00:00
|
|
|
}
|
|
|
|
|
|
|
|
static inline void take_option(char **to, char *from, int *first, int len)
|
|
|
|
{
|
|
|
|
if (!*first) {
|
|
|
|
**to = ',';
|
|
|
|
*to += 1;
|
[PATCH] SELinux: support mls categories for context mounts
Allows commas to be embedded into context mount options (i.e. "-o
context=some_selinux_context_t"), to better support multiple categories,
which are separated by commas and confuse mount.
For example, with the current code:
mount -t iso9660 /dev/cdrom /media/cdrom -o \
ro,context=system_u:object_r:iso9660_t:s0:c1,c3,c4,exec
The context option that will be interpreted by SELinux is
context=system_u:object_r:iso9660_t:s0:c1
instead of
context=system_u:object_r:iso9660_t:s0:c1,c3,c4
The options that will be passed on to the file system will be
ro,c3,c4,exec.
The proposed solution is to allow/require the SELinux context option
specified to mount to use quotes when the context contains a comma.
This patch modifies the option parsing in parse_opts(), contained in
mount.c, to take options after finding a comma only if it hasn't seen a
quote or if the quotes are matched. It also introduces a new function that
will strip the quotes from the context option prior to translation. The
quotes are replaced after the translation is completed to insure that in
the event the raw context contains commas the kernel will be able to
interpret the correct context.
Signed-off-by: Cory Olmo <colmo@TrustedCS.com>
Signed-off-by: James Morris <jmorris@namei.org>
Acked-by: Stephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-09-29 08:58:44 +00:00
|
|
|
} else
|
2005-04-16 22:20:36 +00:00
|
|
|
*first = 0;
|
|
|
|
memcpy(*to, from, len);
|
|
|
|
*to += len;
|
|
|
|
}
|
|
|
|
|
2008-04-17 17:17:49 +00:00
|
|
|
static inline void take_selinux_option(char **to, char *from, int *first,
|
|
|
|
int len)
|
[PATCH] SELinux: support mls categories for context mounts
Allows commas to be embedded into context mount options (i.e. "-o
context=some_selinux_context_t"), to better support multiple categories,
which are separated by commas and confuse mount.
For example, with the current code:
mount -t iso9660 /dev/cdrom /media/cdrom -o \
ro,context=system_u:object_r:iso9660_t:s0:c1,c3,c4,exec
The context option that will be interpreted by SELinux is
context=system_u:object_r:iso9660_t:s0:c1
instead of
context=system_u:object_r:iso9660_t:s0:c1,c3,c4
The options that will be passed on to the file system will be
ro,c3,c4,exec.
The proposed solution is to allow/require the SELinux context option
specified to mount to use quotes when the context contains a comma.
This patch modifies the option parsing in parse_opts(), contained in
mount.c, to take options after finding a comma only if it hasn't seen a
quote or if the quotes are matched. It also introduces a new function that
will strip the quotes from the context option prior to translation. The
quotes are replaced after the translation is completed to insure that in
the event the raw context contains commas the kernel will be able to
interpret the correct context.
Signed-off-by: Cory Olmo <colmo@TrustedCS.com>
Signed-off-by: James Morris <jmorris@namei.org>
Acked-by: Stephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-09-29 08:58:44 +00:00
|
|
|
{
|
|
|
|
int current_size = 0;
|
|
|
|
|
|
|
|
if (!*first) {
|
|
|
|
**to = '|';
|
|
|
|
*to += 1;
|
2008-04-17 17:17:49 +00:00
|
|
|
} else
|
[PATCH] SELinux: support mls categories for context mounts
Allows commas to be embedded into context mount options (i.e. "-o
context=some_selinux_context_t"), to better support multiple categories,
which are separated by commas and confuse mount.
For example, with the current code:
mount -t iso9660 /dev/cdrom /media/cdrom -o \
ro,context=system_u:object_r:iso9660_t:s0:c1,c3,c4,exec
The context option that will be interpreted by SELinux is
context=system_u:object_r:iso9660_t:s0:c1
instead of
context=system_u:object_r:iso9660_t:s0:c1,c3,c4
The options that will be passed on to the file system will be
ro,c3,c4,exec.
The proposed solution is to allow/require the SELinux context option
specified to mount to use quotes when the context contains a comma.
This patch modifies the option parsing in parse_opts(), contained in
mount.c, to take options after finding a comma only if it hasn't seen a
quote or if the quotes are matched. It also introduces a new function that
will strip the quotes from the context option prior to translation. The
quotes are replaced after the translation is completed to insure that in
the event the raw context contains commas the kernel will be able to
interpret the correct context.
Signed-off-by: Cory Olmo <colmo@TrustedCS.com>
Signed-off-by: James Morris <jmorris@namei.org>
Acked-by: Stephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-09-29 08:58:44 +00:00
|
|
|
*first = 0;
|
|
|
|
|
|
|
|
while (current_size < len) {
|
|
|
|
if (*from != '"') {
|
|
|
|
**to = *from;
|
|
|
|
*to += 1;
|
|
|
|
}
|
|
|
|
from += 1;
|
|
|
|
current_size += 1;
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
2008-03-05 15:31:54 +00:00
|
|
|
static int selinux_sb_copy_data(char *orig, char *copy)
|
2005-04-16 22:20:36 +00:00
|
|
|
{
|
|
|
|
int fnosec, fsec, rc = 0;
|
|
|
|
char *in_save, *in_curr, *in_end;
|
|
|
|
char *sec_curr, *nosec_save, *nosec;
|
[PATCH] SELinux: support mls categories for context mounts
Allows commas to be embedded into context mount options (i.e. "-o
context=some_selinux_context_t"), to better support multiple categories,
which are separated by commas and confuse mount.
For example, with the current code:
mount -t iso9660 /dev/cdrom /media/cdrom -o \
ro,context=system_u:object_r:iso9660_t:s0:c1,c3,c4,exec
The context option that will be interpreted by SELinux is
context=system_u:object_r:iso9660_t:s0:c1
instead of
context=system_u:object_r:iso9660_t:s0:c1,c3,c4
The options that will be passed on to the file system will be
ro,c3,c4,exec.
The proposed solution is to allow/require the SELinux context option
specified to mount to use quotes when the context contains a comma.
This patch modifies the option parsing in parse_opts(), contained in
mount.c, to take options after finding a comma only if it hasn't seen a
quote or if the quotes are matched. It also introduces a new function that
will strip the quotes from the context option prior to translation. The
quotes are replaced after the translation is completed to insure that in
the event the raw context contains commas the kernel will be able to
interpret the correct context.
Signed-off-by: Cory Olmo <colmo@TrustedCS.com>
Signed-off-by: James Morris <jmorris@namei.org>
Acked-by: Stephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-09-29 08:58:44 +00:00
|
|
|
int open_quote = 0;
|
2005-04-16 22:20:36 +00:00
|
|
|
|
|
|
|
in_curr = orig;
|
|
|
|
sec_curr = copy;
|
|
|
|
|
|
|
|
nosec = (char *)get_zeroed_page(GFP_KERNEL);
|
|
|
|
if (!nosec) {
|
|
|
|
rc = -ENOMEM;
|
|
|
|
goto out;
|
|
|
|
}
|
|
|
|
|
|
|
|
nosec_save = nosec;
|
|
|
|
fnosec = fsec = 1;
|
|
|
|
in_save = in_end = orig;
|
|
|
|
|
|
|
|
do {
|
[PATCH] SELinux: support mls categories for context mounts
Allows commas to be embedded into context mount options (i.e. "-o
context=some_selinux_context_t"), to better support multiple categories,
which are separated by commas and confuse mount.
For example, with the current code:
mount -t iso9660 /dev/cdrom /media/cdrom -o \
ro,context=system_u:object_r:iso9660_t:s0:c1,c3,c4,exec
The context option that will be interpreted by SELinux is
context=system_u:object_r:iso9660_t:s0:c1
instead of
context=system_u:object_r:iso9660_t:s0:c1,c3,c4
The options that will be passed on to the file system will be
ro,c3,c4,exec.
The proposed solution is to allow/require the SELinux context option
specified to mount to use quotes when the context contains a comma.
This patch modifies the option parsing in parse_opts(), contained in
mount.c, to take options after finding a comma only if it hasn't seen a
quote or if the quotes are matched. It also introduces a new function that
will strip the quotes from the context option prior to translation. The
quotes are replaced after the translation is completed to insure that in
the event the raw context contains commas the kernel will be able to
interpret the correct context.
Signed-off-by: Cory Olmo <colmo@TrustedCS.com>
Signed-off-by: James Morris <jmorris@namei.org>
Acked-by: Stephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-09-29 08:58:44 +00:00
|
|
|
if (*in_end == '"')
|
|
|
|
open_quote = !open_quote;
|
|
|
|
if ((*in_end == ',' && open_quote == 0) ||
|
|
|
|
*in_end == '\0') {
|
2005-04-16 22:20:36 +00:00
|
|
|
int len = in_end - in_curr;
|
|
|
|
|
|
|
|
if (selinux_option(in_curr, len))
|
[PATCH] SELinux: support mls categories for context mounts
Allows commas to be embedded into context mount options (i.e. "-o
context=some_selinux_context_t"), to better support multiple categories,
which are separated by commas and confuse mount.
For example, with the current code:
mount -t iso9660 /dev/cdrom /media/cdrom -o \
ro,context=system_u:object_r:iso9660_t:s0:c1,c3,c4,exec
The context option that will be interpreted by SELinux is
context=system_u:object_r:iso9660_t:s0:c1
instead of
context=system_u:object_r:iso9660_t:s0:c1,c3,c4
The options that will be passed on to the file system will be
ro,c3,c4,exec.
The proposed solution is to allow/require the SELinux context option
specified to mount to use quotes when the context contains a comma.
This patch modifies the option parsing in parse_opts(), contained in
mount.c, to take options after finding a comma only if it hasn't seen a
quote or if the quotes are matched. It also introduces a new function that
will strip the quotes from the context option prior to translation. The
quotes are replaced after the translation is completed to insure that in
the event the raw context contains commas the kernel will be able to
interpret the correct context.
Signed-off-by: Cory Olmo <colmo@TrustedCS.com>
Signed-off-by: James Morris <jmorris@namei.org>
Acked-by: Stephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-09-29 08:58:44 +00:00
|
|
|
take_selinux_option(&sec_curr, in_curr, &fsec, len);
|
2005-04-16 22:20:36 +00:00
|
|
|
else
|
|
|
|
take_option(&nosec, in_curr, &fnosec, len);
|
|
|
|
|
|
|
|
in_curr = in_end + 1;
|
|
|
|
}
|
|
|
|
} while (*in_end++);
|
|
|
|
|
2005-06-30 09:58:51 +00:00
|
|
|
strcpy(in_save, nosec_save);
|
2005-06-22 00:15:18 +00:00
|
|
|
free_page((unsigned long)nosec_save);
|
2005-04-16 22:20:36 +00:00
|
|
|
out:
|
|
|
|
return rc;
|
|
|
|
}
|
|
|
|
|
2011-03-03 21:09:14 +00:00
|
|
|
static int selinux_sb_remount(struct super_block *sb, void *data)
|
|
|
|
{
|
|
|
|
int rc, i, *flags;
|
|
|
|
struct security_mnt_opts opts;
|
|
|
|
char *secdata, **mount_options;
|
|
|
|
struct superblock_security_struct *sbsec = sb->s_security;
|
|
|
|
|
|
|
|
if (!(sbsec->flags & SE_SBINITIALIZED))
|
|
|
|
return 0;
|
|
|
|
|
|
|
|
if (!data)
|
|
|
|
return 0;
|
|
|
|
|
|
|
|
if (sb->s_type->fs_flags & FS_BINARY_MOUNTDATA)
|
|
|
|
return 0;
|
|
|
|
|
|
|
|
security_init_mnt_opts(&opts);
|
|
|
|
secdata = alloc_secdata();
|
|
|
|
if (!secdata)
|
|
|
|
return -ENOMEM;
|
|
|
|
rc = selinux_sb_copy_data(data, secdata);
|
|
|
|
if (rc)
|
|
|
|
goto out_free_secdata;
|
|
|
|
|
|
|
|
rc = selinux_parse_opts_str(secdata, &opts);
|
|
|
|
if (rc)
|
|
|
|
goto out_free_secdata;
|
|
|
|
|
|
|
|
mount_options = opts.mnt_opts;
|
|
|
|
flags = opts.mnt_opts_flags;
|
|
|
|
|
|
|
|
for (i = 0; i < opts.num_mnt_opts; i++) {
|
|
|
|
u32 sid;
|
|
|
|
size_t len;
|
|
|
|
|
2012-10-09 14:56:25 +00:00
|
|
|
if (flags[i] == SBLABEL_MNT)
|
2011-03-03 21:09:14 +00:00
|
|
|
continue;
|
|
|
|
len = strlen(mount_options[i]);
|
2014-03-07 11:44:19 +00:00
|
|
|
rc = security_context_to_sid(mount_options[i], len, &sid,
|
|
|
|
GFP_KERNEL);
|
2011-03-03 21:09:14 +00:00
|
|
|
if (rc) {
|
|
|
|
printk(KERN_WARNING "SELinux: security_context_to_sid"
|
2013-12-15 19:17:45 +00:00
|
|
|
"(%s) failed for (dev %s, type %s) errno=%d\n",
|
|
|
|
mount_options[i], sb->s_id, sb->s_type->name, rc);
|
2011-03-03 21:09:14 +00:00
|
|
|
goto out_free_opts;
|
|
|
|
}
|
|
|
|
rc = -EINVAL;
|
|
|
|
switch (flags[i]) {
|
|
|
|
case FSCONTEXT_MNT:
|
|
|
|
if (bad_option(sbsec, FSCONTEXT_MNT, sbsec->sid, sid))
|
|
|
|
goto out_bad_option;
|
|
|
|
break;
|
|
|
|
case CONTEXT_MNT:
|
|
|
|
if (bad_option(sbsec, CONTEXT_MNT, sbsec->mntpoint_sid, sid))
|
|
|
|
goto out_bad_option;
|
|
|
|
break;
|
|
|
|
case ROOTCONTEXT_MNT: {
|
|
|
|
struct inode_security_struct *root_isec;
|
|
|
|
root_isec = sb->s_root->d_inode->i_security;
|
|
|
|
|
|
|
|
if (bad_option(sbsec, ROOTCONTEXT_MNT, root_isec->sid, sid))
|
|
|
|
goto out_bad_option;
|
|
|
|
break;
|
|
|
|
}
|
|
|
|
case DEFCONTEXT_MNT:
|
|
|
|
if (bad_option(sbsec, DEFCONTEXT_MNT, sbsec->def_sid, sid))
|
|
|
|
goto out_bad_option;
|
|
|
|
break;
|
|
|
|
default:
|
|
|
|
goto out_free_opts;
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
|
|
|
rc = 0;
|
|
|
|
out_free_opts:
|
|
|
|
security_free_mnt_opts(&opts);
|
|
|
|
out_free_secdata:
|
|
|
|
free_secdata(secdata);
|
|
|
|
return rc;
|
|
|
|
out_bad_option:
|
|
|
|
printk(KERN_WARNING "SELinux: unable to change security options "
|
2013-12-15 19:17:45 +00:00
|
|
|
"during remount (dev %s, type=%s)\n", sb->s_id,
|
|
|
|
sb->s_type->name);
|
2011-03-03 21:09:14 +00:00
|
|
|
goto out_free_opts;
|
|
|
|
}
|
|
|
|
|
2008-12-18 23:44:42 +00:00
|
|
|
static int selinux_sb_kern_mount(struct super_block *sb, int flags, void *data)
|
2005-04-16 22:20:36 +00:00
|
|
|
{
|
2008-11-13 23:39:21 +00:00
|
|
|
const struct cred *cred = current_cred();
|
2009-07-14 16:14:09 +00:00
|
|
|
struct common_audit_data ad;
|
2005-04-16 22:20:36 +00:00
|
|
|
int rc;
|
|
|
|
|
|
|
|
rc = superblock_doinit(sb, data);
|
|
|
|
if (rc)
|
|
|
|
return rc;
|
|
|
|
|
2008-12-19 00:41:10 +00:00
|
|
|
/* Allow all mounts performed by the kernel */
|
|
|
|
if (flags & MS_KERNMOUNT)
|
|
|
|
return 0;
|
|
|
|
|
2012-04-04 19:01:43 +00:00
|
|
|
ad.type = LSM_AUDIT_DATA_DENTRY;
|
2011-04-25 17:10:27 +00:00
|
|
|
ad.u.dentry = sb->s_root;
|
2008-11-13 23:39:21 +00:00
|
|
|
return superblock_has_perm(cred, sb, FILESYSTEM__MOUNT, &ad);
|
2005-04-16 22:20:36 +00:00
|
|
|
}
|
|
|
|
|
2006-06-23 09:02:58 +00:00
|
|
|
static int selinux_sb_statfs(struct dentry *dentry)
|
2005-04-16 22:20:36 +00:00
|
|
|
{
|
2008-11-13 23:39:21 +00:00
|
|
|
const struct cred *cred = current_cred();
|
2009-07-14 16:14:09 +00:00
|
|
|
struct common_audit_data ad;
|
2005-04-16 22:20:36 +00:00
|
|
|
|
2012-04-04 19:01:43 +00:00
|
|
|
ad.type = LSM_AUDIT_DATA_DENTRY;
|
2011-04-25 17:10:27 +00:00
|
|
|
ad.u.dentry = dentry->d_sb->s_root;
|
2008-11-13 23:39:21 +00:00
|
|
|
return superblock_has_perm(cred, dentry->d_sb, FILESYSTEM__GETATTR, &ad);
|
2005-04-16 22:20:36 +00:00
|
|
|
}
|
|
|
|
|
2012-10-11 15:42:01 +00:00
|
|
|
static int selinux_mount(const char *dev_name,
|
2008-03-22 21:48:24 +00:00
|
|
|
struct path *path,
|
2012-10-11 15:42:01 +00:00
|
|
|
const char *type,
|
2008-04-17 17:17:49 +00:00
|
|
|
unsigned long flags,
|
|
|
|
void *data)
|
2005-04-16 22:20:36 +00:00
|
|
|
{
|
2008-11-13 23:39:21 +00:00
|
|
|
const struct cred *cred = current_cred();
|
2005-04-16 22:20:36 +00:00
|
|
|
|
|
|
|
if (flags & MS_REMOUNT)
|
2011-12-07 23:16:57 +00:00
|
|
|
return superblock_has_perm(cred, path->dentry->d_sb,
|
2008-04-17 17:17:49 +00:00
|
|
|
FILESYSTEM__REMOUNT, NULL);
|
2005-04-16 22:20:36 +00:00
|
|
|
else
|
2011-04-28 20:04:24 +00:00
|
|
|
return path_has_perm(cred, path, FILE__MOUNTON);
|
2005-04-16 22:20:36 +00:00
|
|
|
}
|
|
|
|
|
|
|
|
static int selinux_umount(struct vfsmount *mnt, int flags)
|
|
|
|
{
|
2008-11-13 23:39:21 +00:00
|
|
|
const struct cred *cred = current_cred();
|
2005-04-16 22:20:36 +00:00
|
|
|
|
2008-11-13 23:39:21 +00:00
|
|
|
return superblock_has_perm(cred, mnt->mnt_sb,
|
2008-04-17 17:17:49 +00:00
|
|
|
FILESYSTEM__UNMOUNT, NULL);
|
2005-04-16 22:20:36 +00:00
|
|
|
}
|
|
|
|
|
|
|
|
/* inode security operations */
|
|
|
|
|
|
|
|
static int selinux_inode_alloc_security(struct inode *inode)
|
|
|
|
{
|
|
|
|
return inode_alloc_security(inode);
|
|
|
|
}
|
|
|
|
|
|
|
|
static void selinux_inode_free_security(struct inode *inode)
|
|
|
|
{
|
|
|
|
inode_free_security(inode);
|
|
|
|
}
|
|
|
|
|
2013-05-22 16:50:34 +00:00
|
|
|
static int selinux_dentry_init_security(struct dentry *dentry, int mode,
|
|
|
|
struct qstr *name, void **ctx,
|
|
|
|
u32 *ctxlen)
|
|
|
|
{
|
|
|
|
const struct cred *cred = current_cred();
|
|
|
|
struct task_security_struct *tsec;
|
|
|
|
struct inode_security_struct *dsec;
|
|
|
|
struct superblock_security_struct *sbsec;
|
|
|
|
struct inode *dir = dentry->d_parent->d_inode;
|
|
|
|
u32 newsid;
|
|
|
|
int rc;
|
|
|
|
|
|
|
|
tsec = cred->security;
|
|
|
|
dsec = dir->i_security;
|
|
|
|
sbsec = dir->i_sb->s_security;
|
|
|
|
|
|
|
|
if (tsec->create_sid && sbsec->behavior != SECURITY_FS_USE_MNTPOINT) {
|
|
|
|
newsid = tsec->create_sid;
|
|
|
|
} else {
|
|
|
|
rc = security_transition_sid(tsec->sid, dsec->sid,
|
|
|
|
inode_mode_to_security_class(mode),
|
|
|
|
name,
|
|
|
|
&newsid);
|
|
|
|
if (rc) {
|
|
|
|
printk(KERN_WARNING
|
|
|
|
"%s: security_transition_sid failed, rc=%d\n",
|
|
|
|
__func__, -rc);
|
|
|
|
return rc;
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
|
|
|
return security_sid_to_context(newsid, (char **)ctx, ctxlen);
|
|
|
|
}
|
|
|
|
|
2005-09-09 20:01:35 +00:00
|
|
|
static int selinux_inode_init_security(struct inode *inode, struct inode *dir,
|
2013-07-24 20:44:02 +00:00
|
|
|
const struct qstr *qstr,
|
|
|
|
const char **name,
|
2011-02-01 16:05:39 +00:00
|
|
|
void **value, size_t *len)
|
2005-09-09 20:01:35 +00:00
|
|
|
{
|
2010-04-22 18:46:19 +00:00
|
|
|
const struct task_security_struct *tsec = current_security();
|
2005-09-09 20:01:35 +00:00
|
|
|
struct inode_security_struct *dsec;
|
|
|
|
struct superblock_security_struct *sbsec;
|
2008-11-13 23:39:19 +00:00
|
|
|
u32 sid, newsid, clen;
|
2005-09-09 20:01:35 +00:00
|
|
|
int rc;
|
2013-07-24 20:44:02 +00:00
|
|
|
char *context;
|
2005-09-09 20:01:35 +00:00
|
|
|
|
|
|
|
dsec = dir->i_security;
|
|
|
|
sbsec = dir->i_sb->s_security;
|
|
|
|
|
2008-11-13 23:39:19 +00:00
|
|
|
sid = tsec->sid;
|
|
|
|
newsid = tsec->create_sid;
|
|
|
|
|
2010-12-02 21:13:40 +00:00
|
|
|
if ((sbsec->flags & SE_SBINITIALIZED) &&
|
|
|
|
(sbsec->behavior == SECURITY_FS_USE_MNTPOINT))
|
|
|
|
newsid = sbsec->mntpoint_sid;
|
2012-10-09 14:56:25 +00:00
|
|
|
else if (!newsid || !(sbsec->flags & SBLABEL_MNT)) {
|
2008-11-13 23:39:19 +00:00
|
|
|
rc = security_transition_sid(sid, dsec->sid,
|
2005-09-09 20:01:35 +00:00
|
|
|
inode_mode_to_security_class(inode->i_mode),
|
SELinux: Use dentry name in new object labeling
Currently SELinux has rules which label new objects according to 3 criteria.
The label of the process creating the object, the label of the parent
directory, and the type of object (reg, dir, char, block, etc.) This patch
adds a 4th criteria, the dentry name, thus we can distinguish between
creating a file in an etc_t directory called shadow and one called motd.
There is no file globbing, regex parsing, or anything mystical. Either the
policy exactly (strcmp) matches the dentry name of the object or it doesn't.
This patch has no changes from today if policy does not implement the new
rules.
Signed-off-by: Eric Paris <eparis@redhat.com>
2011-02-01 16:05:40 +00:00
|
|
|
qstr, &newsid);
|
2005-09-09 20:01:35 +00:00
|
|
|
if (rc) {
|
|
|
|
printk(KERN_WARNING "%s: "
|
|
|
|
"security_transition_sid failed, rc=%d (dev=%s "
|
|
|
|
"ino=%ld)\n",
|
2008-03-05 23:03:59 +00:00
|
|
|
__func__,
|
2005-09-09 20:01:35 +00:00
|
|
|
-rc, inode->i_sb->s_id, inode->i_ino);
|
|
|
|
return rc;
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
2006-09-26 06:32:00 +00:00
|
|
|
/* Possibly defer initialization to selinux_complete_init. */
|
2009-01-16 14:22:02 +00:00
|
|
|
if (sbsec->flags & SE_SBINITIALIZED) {
|
2006-09-26 06:32:00 +00:00
|
|
|
struct inode_security_struct *isec = inode->i_security;
|
|
|
|
isec->sclass = inode_mode_to_security_class(inode->i_mode);
|
|
|
|
isec->sid = newsid;
|
|
|
|
isec->initialized = 1;
|
|
|
|
}
|
2005-09-09 20:01:35 +00:00
|
|
|
|
2012-10-09 14:56:25 +00:00
|
|
|
if (!ss_initialized || !(sbsec->flags & SBLABEL_MNT))
|
2005-11-09 05:34:33 +00:00
|
|
|
return -EOPNOTSUPP;
|
|
|
|
|
2013-07-24 20:44:02 +00:00
|
|
|
if (name)
|
|
|
|
*name = XATTR_SELINUX_SUFFIX;
|
2005-09-09 20:01:35 +00:00
|
|
|
|
2005-09-09 20:01:43 +00:00
|
|
|
if (value && len) {
|
2008-05-07 17:03:20 +00:00
|
|
|
rc = security_sid_to_context_force(newsid, &context, &clen);
|
2013-07-24 20:44:02 +00:00
|
|
|
if (rc)
|
2005-09-09 20:01:43 +00:00
|
|
|
return rc;
|
|
|
|
*value = context;
|
|
|
|
*len = clen;
|
2005-09-09 20:01:35 +00:00
|
|
|
}
|
|
|
|
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
2011-07-26 05:42:34 +00:00
|
|
|
static int selinux_inode_create(struct inode *dir, struct dentry *dentry, umode_t mode)
|
2005-04-16 22:20:36 +00:00
|
|
|
{
|
|
|
|
return may_create(dir, dentry, SECCLASS_FILE);
|
|
|
|
}
|
|
|
|
|
|
|
|
static int selinux_inode_link(struct dentry *old_dentry, struct inode *dir, struct dentry *new_dentry)
|
|
|
|
{
|
|
|
|
return may_link(dir, old_dentry, MAY_LINK);
|
|
|
|
}
|
|
|
|
|
|
|
|
static int selinux_inode_unlink(struct inode *dir, struct dentry *dentry)
|
|
|
|
{
|
|
|
|
return may_link(dir, dentry, MAY_UNLINK);
|
|
|
|
}
|
|
|
|
|
|
|
|
static int selinux_inode_symlink(struct inode *dir, struct dentry *dentry, const char *name)
|
|
|
|
{
|
|
|
|
return may_create(dir, dentry, SECCLASS_LNK_FILE);
|
|
|
|
}
|
|
|
|
|
2011-07-26 05:41:39 +00:00
|
|
|
static int selinux_inode_mkdir(struct inode *dir, struct dentry *dentry, umode_t mask)
|
2005-04-16 22:20:36 +00:00
|
|
|
{
|
|
|
|
return may_create(dir, dentry, SECCLASS_DIR);
|
|
|
|
}
|
|
|
|
|
|
|
|
static int selinux_inode_rmdir(struct inode *dir, struct dentry *dentry)
|
|
|
|
{
|
|
|
|
return may_link(dir, dentry, MAY_RMDIR);
|
|
|
|
}
|
|
|
|
|
2011-07-26 05:52:52 +00:00
|
|
|
static int selinux_inode_mknod(struct inode *dir, struct dentry *dentry, umode_t mode, dev_t dev)
|
2005-04-16 22:20:36 +00:00
|
|
|
{
|
|
|
|
return may_create(dir, dentry, inode_mode_to_security_class(mode));
|
|
|
|
}
|
|
|
|
|
|
|
|
static int selinux_inode_rename(struct inode *old_inode, struct dentry *old_dentry,
|
2008-04-17 17:17:49 +00:00
|
|
|
struct inode *new_inode, struct dentry *new_dentry)
|
2005-04-16 22:20:36 +00:00
|
|
|
{
|
|
|
|
return may_rename(old_inode, old_dentry, new_inode, new_dentry);
|
|
|
|
}
|
|
|
|
|
|
|
|
static int selinux_inode_readlink(struct dentry *dentry)
|
|
|
|
{
|
2008-11-13 23:39:21 +00:00
|
|
|
const struct cred *cred = current_cred();
|
|
|
|
|
2011-04-28 20:04:24 +00:00
|
|
|
return dentry_has_perm(cred, dentry, FILE__READ);
|
2005-04-16 22:20:36 +00:00
|
|
|
}
|
|
|
|
|
|
|
|
static int selinux_inode_follow_link(struct dentry *dentry, struct nameidata *nameidata)
|
|
|
|
{
|
2008-11-13 23:39:21 +00:00
|
|
|
const struct cred *cred = current_cred();
|
2005-04-16 22:20:36 +00:00
|
|
|
|
2011-04-28 20:04:24 +00:00
|
|
|
return dentry_has_perm(cred, dentry, FILE__READ);
|
2005-04-16 22:20:36 +00:00
|
|
|
}
|
|
|
|
|
2012-04-04 19:01:42 +00:00
|
|
|
static noinline int audit_inode_permission(struct inode *inode,
|
|
|
|
u32 perms, u32 audited, u32 denied,
|
|
|
|
unsigned flags)
|
2005-04-16 22:20:36 +00:00
|
|
|
{
|
2010-07-23 15:44:03 +00:00
|
|
|
struct common_audit_data ad;
|
2012-04-04 19:01:42 +00:00
|
|
|
struct inode_security_struct *isec = inode->i_security;
|
|
|
|
int rc;
|
|
|
|
|
2012-04-04 19:01:43 +00:00
|
|
|
ad.type = LSM_AUDIT_DATA_INODE;
|
2012-04-04 19:01:42 +00:00
|
|
|
ad.u.inode = inode;
|
|
|
|
|
|
|
|
rc = slow_avc_audit(current_sid(), isec->sid, isec->sclass, perms,
|
|
|
|
audited, denied, &ad, flags);
|
|
|
|
if (rc)
|
|
|
|
return rc;
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
2011-06-20 23:38:15 +00:00
|
|
|
static int selinux_inode_permission(struct inode *inode, int mask)
|
2005-04-16 22:20:36 +00:00
|
|
|
{
|
2008-11-13 23:39:21 +00:00
|
|
|
const struct cred *cred = current_cred();
|
2010-07-23 15:44:03 +00:00
|
|
|
u32 perms;
|
|
|
|
bool from_access;
|
2011-06-20 23:44:08 +00:00
|
|
|
unsigned flags = mask & MAY_NOT_BLOCK;
|
2012-04-04 19:01:42 +00:00
|
|
|
struct inode_security_struct *isec;
|
|
|
|
u32 sid;
|
|
|
|
struct av_decision avd;
|
|
|
|
int rc, rc2;
|
|
|
|
u32 audited, denied;
|
2005-04-16 22:20:36 +00:00
|
|
|
|
2010-07-23 15:44:03 +00:00
|
|
|
from_access = mask & MAY_ACCESS;
|
2010-07-23 15:43:57 +00:00
|
|
|
mask &= (MAY_READ|MAY_WRITE|MAY_EXEC|MAY_APPEND);
|
|
|
|
|
2010-07-23 15:44:03 +00:00
|
|
|
/* No permission to check. Existence test. */
|
|
|
|
if (!mask)
|
2005-04-16 22:20:36 +00:00
|
|
|
return 0;
|
|
|
|
|
2012-04-04 19:01:42 +00:00
|
|
|
validate_creds(cred);
|
2010-07-23 15:44:03 +00:00
|
|
|
|
2012-04-04 19:01:42 +00:00
|
|
|
if (unlikely(IS_PRIVATE(inode)))
|
|
|
|
return 0;
|
2010-07-23 15:44:03 +00:00
|
|
|
|
|
|
|
perms = file_mask_to_av(inode->i_mode, mask);
|
|
|
|
|
2012-04-04 19:01:42 +00:00
|
|
|
sid = cred_sid(cred);
|
|
|
|
isec = inode->i_security;
|
|
|
|
|
|
|
|
rc = avc_has_perm_noaudit(sid, isec->sid, isec->sclass, perms, 0, &avd);
|
|
|
|
audited = avc_audit_required(perms, &avd, rc,
|
|
|
|
from_access ? FILE__AUDIT_ACCESS : 0,
|
|
|
|
&denied);
|
|
|
|
if (likely(!audited))
|
|
|
|
return rc;
|
|
|
|
|
2012-04-04 19:01:42 +00:00
|
|
|
rc2 = audit_inode_permission(inode, perms, audited, denied, flags);
|
2012-04-04 19:01:42 +00:00
|
|
|
if (rc2)
|
|
|
|
return rc2;
|
|
|
|
return rc;
|
2005-04-16 22:20:36 +00:00
|
|
|
}
|
|
|
|
|
|
|
|
static int selinux_inode_setattr(struct dentry *dentry, struct iattr *iattr)
|
|
|
|
{
|
2008-11-13 23:39:21 +00:00
|
|
|
const struct cred *cred = current_cred();
|
2009-08-21 02:29:02 +00:00
|
|
|
unsigned int ia_valid = iattr->ia_valid;
|
2012-04-04 17:45:34 +00:00
|
|
|
__u32 av = FILE__WRITE;
|
2005-04-16 22:20:36 +00:00
|
|
|
|
2009-08-21 02:29:02 +00:00
|
|
|
/* ATTR_FORCE is just used for ATTR_KILL_S[UG]ID. */
|
|
|
|
if (ia_valid & ATTR_FORCE) {
|
|
|
|
ia_valid &= ~(ATTR_KILL_SUID | ATTR_KILL_SGID | ATTR_MODE |
|
|
|
|
ATTR_FORCE);
|
|
|
|
if (!ia_valid)
|
|
|
|
return 0;
|
|
|
|
}
|
2005-04-16 22:20:36 +00:00
|
|
|
|
2009-08-21 02:29:02 +00:00
|
|
|
if (ia_valid & (ATTR_MODE | ATTR_UID | ATTR_GID |
|
|
|
|
ATTR_ATIME_SET | ATTR_MTIME_SET | ATTR_TIMES_SET))
|
2011-04-28 20:04:24 +00:00
|
|
|
return dentry_has_perm(cred, dentry, FILE__SETATTR);
|
2005-04-16 22:20:36 +00:00
|
|
|
|
2012-07-06 18:13:30 +00:00
|
|
|
if (selinux_policycap_openperm && (ia_valid & ATTR_SIZE))
|
2012-04-04 17:45:34 +00:00
|
|
|
av |= FILE__OPEN;
|
|
|
|
|
|
|
|
return dentry_has_perm(cred, dentry, av);
|
2005-04-16 22:20:36 +00:00
|
|
|
}
|
|
|
|
|
|
|
|
static int selinux_inode_getattr(struct vfsmount *mnt, struct dentry *dentry)
|
|
|
|
{
|
2008-11-13 23:39:21 +00:00
|
|
|
const struct cred *cred = current_cred();
|
2011-04-28 20:04:24 +00:00
|
|
|
struct path path;
|
|
|
|
|
|
|
|
path.dentry = dentry;
|
|
|
|
path.mnt = mnt;
|
2008-11-13 23:39:21 +00:00
|
|
|
|
2011-04-28 20:04:24 +00:00
|
|
|
return path_has_perm(cred, &path, FILE__GETATTR);
|
2005-04-16 22:20:36 +00:00
|
|
|
}
|
|
|
|
|
2008-04-29 07:59:41 +00:00
|
|
|
static int selinux_inode_setotherxattr(struct dentry *dentry, const char *name)
|
Implement file posix capabilities
Implement file posix capabilities. This allows programs to be given a
subset of root's powers regardless of who runs them, without having to use
setuid and giving the binary all of root's powers.
This version works with Kaigai Kohei's userspace tools, found at
http://www.kaigai.gr.jp/index.php. For more information on how to use this
patch, Chris Friedhoff has posted a nice page at
http://www.friedhoff.org/fscaps.html.
Changelog:
Nov 27:
Incorporate fixes from Andrew Morton
(security-introduce-file-caps-tweaks and
security-introduce-file-caps-warning-fix)
Fix Kconfig dependency.
Fix change signaling behavior when file caps are not compiled in.
Nov 13:
Integrate comments from Alexey: Remove CONFIG_ ifdef from
capability.h, and use %zd for printing a size_t.
Nov 13:
Fix endianness warnings by sparse as suggested by Alexey
Dobriyan.
Nov 09:
Address warnings of unused variables at cap_bprm_set_security
when file capabilities are disabled, and simultaneously clean
up the code a little, by pulling the new code into a helper
function.
Nov 08:
For pointers to required userspace tools and how to use
them, see http://www.friedhoff.org/fscaps.html.
Nov 07:
Fix the calculation of the highest bit checked in
check_cap_sanity().
Nov 07:
Allow file caps to be enabled without CONFIG_SECURITY, since
capabilities are the default.
Hook cap_task_setscheduler when !CONFIG_SECURITY.
Move capable(TASK_KILL) to end of cap_task_kill to reduce
audit messages.
Nov 05:
Add secondary calls in selinux/hooks.c to task_setioprio and
task_setscheduler so that selinux and capabilities with file
cap support can be stacked.
Sep 05:
As Seth Arnold points out, uid checks are out of place
for capability code.
Sep 01:
Define task_setscheduler, task_setioprio, cap_task_kill, and
task_setnice to make sure a user cannot affect a process in which
they called a program with some fscaps.
One remaining question is the note under task_setscheduler: are we
ok with CAP_SYS_NICE being sufficient to confine a process to a
cpuset?
It is a semantic change, as without fsccaps, attach_task doesn't
allow CAP_SYS_NICE to override the uid equivalence check. But since
it uses security_task_setscheduler, which elsewhere is used where
CAP_SYS_NICE can be used to override the uid equivalence check,
fixing it might be tough.
task_setscheduler
note: this also controls cpuset:attach_task. Are we ok with
CAP_SYS_NICE being used to confine to a cpuset?
task_setioprio
task_setnice
sys_setpriority uses this (through set_one_prio) for another
process. Need same checks as setrlimit
Aug 21:
Updated secureexec implementation to reflect the fact that
euid and uid might be the same and nonzero, but the process
might still have elevated caps.
Aug 15:
Handle endianness of xattrs.
Enforce capability version match between kernel and disk.
Enforce that no bits beyond the known max capability are
set, else return -EPERM.
With this extra processing, it may be worth reconsidering
doing all the work at bprm_set_security rather than
d_instantiate.
Aug 10:
Always call getxattr at bprm_set_security, rather than
caching it at d_instantiate.
[morgan@kernel.org: file-caps clean up for linux/capability.h]
[bunk@kernel.org: unexport cap_inode_killpriv]
Signed-off-by: Serge E. Hallyn <serue@us.ibm.com>
Cc: Stephen Smalley <sds@tycho.nsa.gov>
Cc: James Morris <jmorris@namei.org>
Cc: Chris Wright <chrisw@sous-sol.org>
Cc: Andrew Morgan <morgan@kernel.org>
Signed-off-by: Andrew Morgan <morgan@kernel.org>
Signed-off-by: Adrian Bunk <bunk@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-17 06:31:36 +00:00
|
|
|
{
|
2008-11-13 23:39:21 +00:00
|
|
|
const struct cred *cred = current_cred();
|
|
|
|
|
Implement file posix capabilities
Implement file posix capabilities. This allows programs to be given a
subset of root's powers regardless of who runs them, without having to use
setuid and giving the binary all of root's powers.
This version works with Kaigai Kohei's userspace tools, found at
http://www.kaigai.gr.jp/index.php. For more information on how to use this
patch, Chris Friedhoff has posted a nice page at
http://www.friedhoff.org/fscaps.html.
Changelog:
Nov 27:
Incorporate fixes from Andrew Morton
(security-introduce-file-caps-tweaks and
security-introduce-file-caps-warning-fix)
Fix Kconfig dependency.
Fix change signaling behavior when file caps are not compiled in.
Nov 13:
Integrate comments from Alexey: Remove CONFIG_ ifdef from
capability.h, and use %zd for printing a size_t.
Nov 13:
Fix endianness warnings by sparse as suggested by Alexey
Dobriyan.
Nov 09:
Address warnings of unused variables at cap_bprm_set_security
when file capabilities are disabled, and simultaneously clean
up the code a little, by pulling the new code into a helper
function.
Nov 08:
For pointers to required userspace tools and how to use
them, see http://www.friedhoff.org/fscaps.html.
Nov 07:
Fix the calculation of the highest bit checked in
check_cap_sanity().
Nov 07:
Allow file caps to be enabled without CONFIG_SECURITY, since
capabilities are the default.
Hook cap_task_setscheduler when !CONFIG_SECURITY.
Move capable(TASK_KILL) to end of cap_task_kill to reduce
audit messages.
Nov 05:
Add secondary calls in selinux/hooks.c to task_setioprio and
task_setscheduler so that selinux and capabilities with file
cap support can be stacked.
Sep 05:
As Seth Arnold points out, uid checks are out of place
for capability code.
Sep 01:
Define task_setscheduler, task_setioprio, cap_task_kill, and
task_setnice to make sure a user cannot affect a process in which
they called a program with some fscaps.
One remaining question is the note under task_setscheduler: are we
ok with CAP_SYS_NICE being sufficient to confine a process to a
cpuset?
It is a semantic change, as without fsccaps, attach_task doesn't
allow CAP_SYS_NICE to override the uid equivalence check. But since
it uses security_task_setscheduler, which elsewhere is used where
CAP_SYS_NICE can be used to override the uid equivalence check,
fixing it might be tough.
task_setscheduler
note: this also controls cpuset:attach_task. Are we ok with
CAP_SYS_NICE being used to confine to a cpuset?
task_setioprio
task_setnice
sys_setpriority uses this (through set_one_prio) for another
process. Need same checks as setrlimit
Aug 21:
Updated secureexec implementation to reflect the fact that
euid and uid might be the same and nonzero, but the process
might still have elevated caps.
Aug 15:
Handle endianness of xattrs.
Enforce capability version match between kernel and disk.
Enforce that no bits beyond the known max capability are
set, else return -EPERM.
With this extra processing, it may be worth reconsidering
doing all the work at bprm_set_security rather than
d_instantiate.
Aug 10:
Always call getxattr at bprm_set_security, rather than
caching it at d_instantiate.
[morgan@kernel.org: file-caps clean up for linux/capability.h]
[bunk@kernel.org: unexport cap_inode_killpriv]
Signed-off-by: Serge E. Hallyn <serue@us.ibm.com>
Cc: Stephen Smalley <sds@tycho.nsa.gov>
Cc: James Morris <jmorris@namei.org>
Cc: Chris Wright <chrisw@sous-sol.org>
Cc: Andrew Morgan <morgan@kernel.org>
Signed-off-by: Andrew Morgan <morgan@kernel.org>
Signed-off-by: Adrian Bunk <bunk@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-17 06:31:36 +00:00
|
|
|
if (!strncmp(name, XATTR_SECURITY_PREFIX,
|
|
|
|
sizeof XATTR_SECURITY_PREFIX - 1)) {
|
|
|
|
if (!strcmp(name, XATTR_NAME_CAPS)) {
|
|
|
|
if (!capable(CAP_SETFCAP))
|
|
|
|
return -EPERM;
|
|
|
|
} else if (!capable(CAP_SYS_ADMIN)) {
|
|
|
|
/* A different attribute in the security namespace.
|
|
|
|
Restrict to administrator. */
|
|
|
|
return -EPERM;
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
|
|
|
/* Not an attribute we recognize, so just check the
|
|
|
|
ordinary setattr permission. */
|
2011-04-28 20:04:24 +00:00
|
|
|
return dentry_has_perm(cred, dentry, FILE__SETATTR);
|
Implement file posix capabilities
Implement file posix capabilities. This allows programs to be given a
subset of root's powers regardless of who runs them, without having to use
setuid and giving the binary all of root's powers.
This version works with Kaigai Kohei's userspace tools, found at
http://www.kaigai.gr.jp/index.php. For more information on how to use this
patch, Chris Friedhoff has posted a nice page at
http://www.friedhoff.org/fscaps.html.
Changelog:
Nov 27:
Incorporate fixes from Andrew Morton
(security-introduce-file-caps-tweaks and
security-introduce-file-caps-warning-fix)
Fix Kconfig dependency.
Fix change signaling behavior when file caps are not compiled in.
Nov 13:
Integrate comments from Alexey: Remove CONFIG_ ifdef from
capability.h, and use %zd for printing a size_t.
Nov 13:
Fix endianness warnings by sparse as suggested by Alexey
Dobriyan.
Nov 09:
Address warnings of unused variables at cap_bprm_set_security
when file capabilities are disabled, and simultaneously clean
up the code a little, by pulling the new code into a helper
function.
Nov 08:
For pointers to required userspace tools and how to use
them, see http://www.friedhoff.org/fscaps.html.
Nov 07:
Fix the calculation of the highest bit checked in
check_cap_sanity().
Nov 07:
Allow file caps to be enabled without CONFIG_SECURITY, since
capabilities are the default.
Hook cap_task_setscheduler when !CONFIG_SECURITY.
Move capable(TASK_KILL) to end of cap_task_kill to reduce
audit messages.
Nov 05:
Add secondary calls in selinux/hooks.c to task_setioprio and
task_setscheduler so that selinux and capabilities with file
cap support can be stacked.
Sep 05:
As Seth Arnold points out, uid checks are out of place
for capability code.
Sep 01:
Define task_setscheduler, task_setioprio, cap_task_kill, and
task_setnice to make sure a user cannot affect a process in which
they called a program with some fscaps.
One remaining question is the note under task_setscheduler: are we
ok with CAP_SYS_NICE being sufficient to confine a process to a
cpuset?
It is a semantic change, as without fsccaps, attach_task doesn't
allow CAP_SYS_NICE to override the uid equivalence check. But since
it uses security_task_setscheduler, which elsewhere is used where
CAP_SYS_NICE can be used to override the uid equivalence check,
fixing it might be tough.
task_setscheduler
note: this also controls cpuset:attach_task. Are we ok with
CAP_SYS_NICE being used to confine to a cpuset?
task_setioprio
task_setnice
sys_setpriority uses this (through set_one_prio) for another
process. Need same checks as setrlimit
Aug 21:
Updated secureexec implementation to reflect the fact that
euid and uid might be the same and nonzero, but the process
might still have elevated caps.
Aug 15:
Handle endianness of xattrs.
Enforce capability version match between kernel and disk.
Enforce that no bits beyond the known max capability are
set, else return -EPERM.
With this extra processing, it may be worth reconsidering
doing all the work at bprm_set_security rather than
d_instantiate.
Aug 10:
Always call getxattr at bprm_set_security, rather than
caching it at d_instantiate.
[morgan@kernel.org: file-caps clean up for linux/capability.h]
[bunk@kernel.org: unexport cap_inode_killpriv]
Signed-off-by: Serge E. Hallyn <serue@us.ibm.com>
Cc: Stephen Smalley <sds@tycho.nsa.gov>
Cc: James Morris <jmorris@namei.org>
Cc: Chris Wright <chrisw@sous-sol.org>
Cc: Andrew Morgan <morgan@kernel.org>
Signed-off-by: Andrew Morgan <morgan@kernel.org>
Signed-off-by: Adrian Bunk <bunk@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-17 06:31:36 +00:00
|
|
|
}
|
|
|
|
|
2008-04-29 07:59:41 +00:00
|
|
|
static int selinux_inode_setxattr(struct dentry *dentry, const char *name,
|
|
|
|
const void *value, size_t size, int flags)
|
2005-04-16 22:20:36 +00:00
|
|
|
{
|
|
|
|
struct inode *inode = dentry->d_inode;
|
|
|
|
struct inode_security_struct *isec = inode->i_security;
|
|
|
|
struct superblock_security_struct *sbsec;
|
2009-07-14 16:14:09 +00:00
|
|
|
struct common_audit_data ad;
|
2008-11-13 23:39:19 +00:00
|
|
|
u32 newsid, sid = current_sid();
|
2005-04-16 22:20:36 +00:00
|
|
|
int rc = 0;
|
|
|
|
|
Implement file posix capabilities
Implement file posix capabilities. This allows programs to be given a
subset of root's powers regardless of who runs them, without having to use
setuid and giving the binary all of root's powers.
This version works with Kaigai Kohei's userspace tools, found at
http://www.kaigai.gr.jp/index.php. For more information on how to use this
patch, Chris Friedhoff has posted a nice page at
http://www.friedhoff.org/fscaps.html.
Changelog:
Nov 27:
Incorporate fixes from Andrew Morton
(security-introduce-file-caps-tweaks and
security-introduce-file-caps-warning-fix)
Fix Kconfig dependency.
Fix change signaling behavior when file caps are not compiled in.
Nov 13:
Integrate comments from Alexey: Remove CONFIG_ ifdef from
capability.h, and use %zd for printing a size_t.
Nov 13:
Fix endianness warnings by sparse as suggested by Alexey
Dobriyan.
Nov 09:
Address warnings of unused variables at cap_bprm_set_security
when file capabilities are disabled, and simultaneously clean
up the code a little, by pulling the new code into a helper
function.
Nov 08:
For pointers to required userspace tools and how to use
them, see http://www.friedhoff.org/fscaps.html.
Nov 07:
Fix the calculation of the highest bit checked in
check_cap_sanity().
Nov 07:
Allow file caps to be enabled without CONFIG_SECURITY, since
capabilities are the default.
Hook cap_task_setscheduler when !CONFIG_SECURITY.
Move capable(TASK_KILL) to end of cap_task_kill to reduce
audit messages.
Nov 05:
Add secondary calls in selinux/hooks.c to task_setioprio and
task_setscheduler so that selinux and capabilities with file
cap support can be stacked.
Sep 05:
As Seth Arnold points out, uid checks are out of place
for capability code.
Sep 01:
Define task_setscheduler, task_setioprio, cap_task_kill, and
task_setnice to make sure a user cannot affect a process in which
they called a program with some fscaps.
One remaining question is the note under task_setscheduler: are we
ok with CAP_SYS_NICE being sufficient to confine a process to a
cpuset?
It is a semantic change, as without fsccaps, attach_task doesn't
allow CAP_SYS_NICE to override the uid equivalence check. But since
it uses security_task_setscheduler, which elsewhere is used where
CAP_SYS_NICE can be used to override the uid equivalence check,
fixing it might be tough.
task_setscheduler
note: this also controls cpuset:attach_task. Are we ok with
CAP_SYS_NICE being used to confine to a cpuset?
task_setioprio
task_setnice
sys_setpriority uses this (through set_one_prio) for another
process. Need same checks as setrlimit
Aug 21:
Updated secureexec implementation to reflect the fact that
euid and uid might be the same and nonzero, but the process
might still have elevated caps.
Aug 15:
Handle endianness of xattrs.
Enforce capability version match between kernel and disk.
Enforce that no bits beyond the known max capability are
set, else return -EPERM.
With this extra processing, it may be worth reconsidering
doing all the work at bprm_set_security rather than
d_instantiate.
Aug 10:
Always call getxattr at bprm_set_security, rather than
caching it at d_instantiate.
[morgan@kernel.org: file-caps clean up for linux/capability.h]
[bunk@kernel.org: unexport cap_inode_killpriv]
Signed-off-by: Serge E. Hallyn <serue@us.ibm.com>
Cc: Stephen Smalley <sds@tycho.nsa.gov>
Cc: James Morris <jmorris@namei.org>
Cc: Chris Wright <chrisw@sous-sol.org>
Cc: Andrew Morgan <morgan@kernel.org>
Signed-off-by: Andrew Morgan <morgan@kernel.org>
Signed-off-by: Adrian Bunk <bunk@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-17 06:31:36 +00:00
|
|
|
if (strcmp(name, XATTR_NAME_SELINUX))
|
|
|
|
return selinux_inode_setotherxattr(dentry, name);
|
2005-04-16 22:20:36 +00:00
|
|
|
|
|
|
|
sbsec = inode->i_sb->s_security;
|
2012-10-09 14:56:25 +00:00
|
|
|
if (!(sbsec->flags & SBLABEL_MNT))
|
2005-04-16 22:20:36 +00:00
|
|
|
return -EOPNOTSUPP;
|
|
|
|
|
2011-03-23 23:43:26 +00:00
|
|
|
if (!inode_owner_or_capable(inode))
|
2005-04-16 22:20:36 +00:00
|
|
|
return -EPERM;
|
|
|
|
|
2012-04-04 19:01:43 +00:00
|
|
|
ad.type = LSM_AUDIT_DATA_DENTRY;
|
2011-04-25 17:10:27 +00:00
|
|
|
ad.u.dentry = dentry;
|
2005-04-16 22:20:36 +00:00
|
|
|
|
2008-11-13 23:39:19 +00:00
|
|
|
rc = avc_has_perm(sid, isec->sid, isec->sclass,
|
2005-04-16 22:20:36 +00:00
|
|
|
FILE__RELABELFROM, &ad);
|
|
|
|
if (rc)
|
|
|
|
return rc;
|
|
|
|
|
2014-03-07 11:44:19 +00:00
|
|
|
rc = security_context_to_sid(value, size, &newsid, GFP_KERNEL);
|
2008-05-07 17:03:20 +00:00
|
|
|
if (rc == -EINVAL) {
|
2012-04-04 17:45:49 +00:00
|
|
|
if (!capable(CAP_MAC_ADMIN)) {
|
|
|
|
struct audit_buffer *ab;
|
|
|
|
size_t audit_size;
|
|
|
|
const char *str;
|
|
|
|
|
|
|
|
/* We strip a nul only if it is at the end, otherwise the
|
|
|
|
* context contains a nul and we should audit that */
|
selinux: fix selinux_inode_setxattr oops
OK, what we have so far is e.g.
setxattr(path, name, whatever, 0, XATTR_REPLACE)
with name being good enough to get through xattr_permission().
Then we reach security_inode_setxattr() with the desired value and size.
Aha. name should begin with "security.selinux", or we won't get that
far in selinux_inode_setxattr(). Suppose we got there and have enough
permissions to relabel that sucker. We call security_context_to_sid()
with value == NULL, size == 0. OK, we want ss_initialized to be non-zero.
I.e. after everything had been set up and running. No problem...
We do 1-byte kmalloc(), zero-length memcpy() (which doesn't oops, even
thought the source is NULL) and put a NUL there. I.e. form an empty
string. string_to_context_struct() is called and looks for the first
':' in there. Not found, -EINVAL we get. OK, security_context_to_sid_core()
has rc == -EINVAL, force == 0, so it silently returns -EINVAL.
All it takes now is not having CAP_MAC_ADMIN and we are fucked.
All right, it might be a different bug (modulo strange code quoted in the
report), but it's real. Easily fixed, AFAICS:
Deal with size == 0, value == NULL case in selinux_inode_setxattr()
Cc: stable@vger.kernel.org
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Tested-by: Dave Jones <davej@redhat.com>
Reported-by: Dave Jones <davej@redhat.com>
Signed-off-by: James Morris <james.l.morris@oracle.com>
2012-06-09 07:15:16 +00:00
|
|
|
if (value) {
|
|
|
|
str = value;
|
|
|
|
if (str[size - 1] == '\0')
|
|
|
|
audit_size = size - 1;
|
|
|
|
else
|
|
|
|
audit_size = size;
|
|
|
|
} else {
|
|
|
|
str = "";
|
|
|
|
audit_size = 0;
|
|
|
|
}
|
2012-04-04 17:45:49 +00:00
|
|
|
ab = audit_log_start(current->audit_context, GFP_ATOMIC, AUDIT_SELINUX_ERR);
|
|
|
|
audit_log_format(ab, "op=setxattr invalid_context=");
|
|
|
|
audit_log_n_untrustedstring(ab, value, audit_size);
|
|
|
|
audit_log_end(ab);
|
|
|
|
|
2008-05-07 17:03:20 +00:00
|
|
|
return rc;
|
2012-04-04 17:45:49 +00:00
|
|
|
}
|
2008-05-07 17:03:20 +00:00
|
|
|
rc = security_context_to_sid_force(value, size, &newsid);
|
|
|
|
}
|
2005-04-16 22:20:36 +00:00
|
|
|
if (rc)
|
|
|
|
return rc;
|
|
|
|
|
2008-11-13 23:39:19 +00:00
|
|
|
rc = avc_has_perm(sid, newsid, isec->sclass,
|
2005-04-16 22:20:36 +00:00
|
|
|
FILE__RELABELTO, &ad);
|
|
|
|
if (rc)
|
|
|
|
return rc;
|
|
|
|
|
2008-11-13 23:39:19 +00:00
|
|
|
rc = security_validate_transition(isec->sid, newsid, sid,
|
2008-04-17 17:17:49 +00:00
|
|
|
isec->sclass);
|
2005-04-16 22:20:36 +00:00
|
|
|
if (rc)
|
|
|
|
return rc;
|
|
|
|
|
|
|
|
return avc_has_perm(newsid,
|
|
|
|
sbsec->sid,
|
|
|
|
SECCLASS_FILESYSTEM,
|
|
|
|
FILESYSTEM__ASSOCIATE,
|
|
|
|
&ad);
|
|
|
|
}
|
|
|
|
|
2008-04-29 07:59:41 +00:00
|
|
|
static void selinux_inode_post_setxattr(struct dentry *dentry, const char *name,
|
2008-05-14 15:27:45 +00:00
|
|
|
const void *value, size_t size,
|
2008-04-29 07:59:41 +00:00
|
|
|
int flags)
|
2005-04-16 22:20:36 +00:00
|
|
|
{
|
|
|
|
struct inode *inode = dentry->d_inode;
|
|
|
|
struct inode_security_struct *isec = inode->i_security;
|
|
|
|
u32 newsid;
|
|
|
|
int rc;
|
|
|
|
|
|
|
|
if (strcmp(name, XATTR_NAME_SELINUX)) {
|
|
|
|
/* Not an attribute we recognize, so nothing to do. */
|
|
|
|
return;
|
|
|
|
}
|
|
|
|
|
2008-05-07 17:03:20 +00:00
|
|
|
rc = security_context_to_sid_force(value, size, &newsid);
|
2005-04-16 22:20:36 +00:00
|
|
|
if (rc) {
|
2008-05-07 17:03:20 +00:00
|
|
|
printk(KERN_ERR "SELinux: unable to map context to SID"
|
|
|
|
"for (%s, %lu), rc=%d\n",
|
|
|
|
inode->i_sb->s_id, inode->i_ino, -rc);
|
2005-04-16 22:20:36 +00:00
|
|
|
return;
|
|
|
|
}
|
|
|
|
|
2013-05-22 16:50:44 +00:00
|
|
|
isec->sclass = inode_mode_to_security_class(inode->i_mode);
|
2005-04-16 22:20:36 +00:00
|
|
|
isec->sid = newsid;
|
2013-05-22 16:50:44 +00:00
|
|
|
isec->initialized = 1;
|
|
|
|
|
2005-04-16 22:20:36 +00:00
|
|
|
return;
|
|
|
|
}
|
|
|
|
|
2008-04-29 07:59:41 +00:00
|
|
|
static int selinux_inode_getxattr(struct dentry *dentry, const char *name)
|
2005-04-16 22:20:36 +00:00
|
|
|
{
|
2008-11-13 23:39:21 +00:00
|
|
|
const struct cred *cred = current_cred();
|
|
|
|
|
2011-04-28 20:04:24 +00:00
|
|
|
return dentry_has_perm(cred, dentry, FILE__GETATTR);
|
2005-04-16 22:20:36 +00:00
|
|
|
}
|
|
|
|
|
2008-04-17 17:17:49 +00:00
|
|
|
static int selinux_inode_listxattr(struct dentry *dentry)
|
2005-04-16 22:20:36 +00:00
|
|
|
{
|
2008-11-13 23:39:21 +00:00
|
|
|
const struct cred *cred = current_cred();
|
|
|
|
|
2011-04-28 20:04:24 +00:00
|
|
|
return dentry_has_perm(cred, dentry, FILE__GETATTR);
|
2005-04-16 22:20:36 +00:00
|
|
|
}
|
|
|
|
|
2008-04-29 07:59:41 +00:00
|
|
|
static int selinux_inode_removexattr(struct dentry *dentry, const char *name)
|
2005-04-16 22:20:36 +00:00
|
|
|
{
|
Implement file posix capabilities
Implement file posix capabilities. This allows programs to be given a
subset of root's powers regardless of who runs them, without having to use
setuid and giving the binary all of root's powers.
This version works with Kaigai Kohei's userspace tools, found at
http://www.kaigai.gr.jp/index.php. For more information on how to use this
patch, Chris Friedhoff has posted a nice page at
http://www.friedhoff.org/fscaps.html.
Changelog:
Nov 27:
Incorporate fixes from Andrew Morton
(security-introduce-file-caps-tweaks and
security-introduce-file-caps-warning-fix)
Fix Kconfig dependency.
Fix change signaling behavior when file caps are not compiled in.
Nov 13:
Integrate comments from Alexey: Remove CONFIG_ ifdef from
capability.h, and use %zd for printing a size_t.
Nov 13:
Fix endianness warnings by sparse as suggested by Alexey
Dobriyan.
Nov 09:
Address warnings of unused variables at cap_bprm_set_security
when file capabilities are disabled, and simultaneously clean
up the code a little, by pulling the new code into a helper
function.
Nov 08:
For pointers to required userspace tools and how to use
them, see http://www.friedhoff.org/fscaps.html.
Nov 07:
Fix the calculation of the highest bit checked in
check_cap_sanity().
Nov 07:
Allow file caps to be enabled without CONFIG_SECURITY, since
capabilities are the default.
Hook cap_task_setscheduler when !CONFIG_SECURITY.
Move capable(TASK_KILL) to end of cap_task_kill to reduce
audit messages.
Nov 05:
Add secondary calls in selinux/hooks.c to task_setioprio and
task_setscheduler so that selinux and capabilities with file
cap support can be stacked.
Sep 05:
As Seth Arnold points out, uid checks are out of place
for capability code.
Sep 01:
Define task_setscheduler, task_setioprio, cap_task_kill, and
task_setnice to make sure a user cannot affect a process in which
they called a program with some fscaps.
One remaining question is the note under task_setscheduler: are we
ok with CAP_SYS_NICE being sufficient to confine a process to a
cpuset?
It is a semantic change, as without fsccaps, attach_task doesn't
allow CAP_SYS_NICE to override the uid equivalence check. But since
it uses security_task_setscheduler, which elsewhere is used where
CAP_SYS_NICE can be used to override the uid equivalence check,
fixing it might be tough.
task_setscheduler
note: this also controls cpuset:attach_task. Are we ok with
CAP_SYS_NICE being used to confine to a cpuset?
task_setioprio
task_setnice
sys_setpriority uses this (through set_one_prio) for another
process. Need same checks as setrlimit
Aug 21:
Updated secureexec implementation to reflect the fact that
euid and uid might be the same and nonzero, but the process
might still have elevated caps.
Aug 15:
Handle endianness of xattrs.
Enforce capability version match between kernel and disk.
Enforce that no bits beyond the known max capability are
set, else return -EPERM.
With this extra processing, it may be worth reconsidering
doing all the work at bprm_set_security rather than
d_instantiate.
Aug 10:
Always call getxattr at bprm_set_security, rather than
caching it at d_instantiate.
[morgan@kernel.org: file-caps clean up for linux/capability.h]
[bunk@kernel.org: unexport cap_inode_killpriv]
Signed-off-by: Serge E. Hallyn <serue@us.ibm.com>
Cc: Stephen Smalley <sds@tycho.nsa.gov>
Cc: James Morris <jmorris@namei.org>
Cc: Chris Wright <chrisw@sous-sol.org>
Cc: Andrew Morgan <morgan@kernel.org>
Signed-off-by: Andrew Morgan <morgan@kernel.org>
Signed-off-by: Adrian Bunk <bunk@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-17 06:31:36 +00:00
|
|
|
if (strcmp(name, XATTR_NAME_SELINUX))
|
|
|
|
return selinux_inode_setotherxattr(dentry, name);
|
2005-04-16 22:20:36 +00:00
|
|
|
|
|
|
|
/* No one is allowed to remove a SELinux security label.
|
|
|
|
You can change the label, but all data must be labeled. */
|
|
|
|
return -EACCES;
|
|
|
|
}
|
|
|
|
|
2005-10-30 22:59:22 +00:00
|
|
|
/*
|
2008-05-21 18:16:12 +00:00
|
|
|
* Copy the inode security context value to the user.
|
2005-10-30 22:59:22 +00:00
|
|
|
*
|
|
|
|
* Permission check is handled by selinux_inode_getxattr hook.
|
|
|
|
*/
|
2008-02-05 06:29:39 +00:00
|
|
|
static int selinux_inode_getsecurity(const struct inode *inode, const char *name, void **buffer, bool alloc)
|
2005-04-16 22:20:36 +00:00
|
|
|
{
|
2008-02-05 06:29:39 +00:00
|
|
|
u32 size;
|
|
|
|
int error;
|
|
|
|
char *context = NULL;
|
2005-04-16 22:20:36 +00:00
|
|
|
struct inode_security_struct *isec = inode->i_security;
|
2005-10-30 22:59:22 +00:00
|
|
|
|
2005-11-03 17:15:16 +00:00
|
|
|
if (strcmp(name, XATTR_SELINUX_SUFFIX))
|
|
|
|
return -EOPNOTSUPP;
|
2005-10-30 22:59:22 +00:00
|
|
|
|
2008-05-21 18:16:12 +00:00
|
|
|
/*
|
|
|
|
* If the caller has CAP_MAC_ADMIN, then get the raw context
|
|
|
|
* value even if it is not defined by current policy; otherwise,
|
|
|
|
* use the in-core value under current policy.
|
|
|
|
* Use the non-auditing forms of the permission checks since
|
|
|
|
* getxattr may be called by unprivileged processes commonly
|
|
|
|
* and lack of permission just means that we fall back to the
|
|
|
|
* in-core context value, not a denial.
|
|
|
|
*/
|
2012-01-03 17:25:14 +00:00
|
|
|
error = selinux_capable(current_cred(), &init_user_ns, CAP_MAC_ADMIN,
|
CRED: Fix regression in cap_capable() as shown up by sys_faccessat() [ver #3]
Fix a regression in cap_capable() due to:
commit 3b11a1decef07c19443d24ae926982bc8ec9f4c0
Author: David Howells <dhowells@redhat.com>
Date: Fri Nov 14 10:39:26 2008 +1100
CRED: Differentiate objective and effective subjective credentials on a task
The problem is that the above patch allows a process to have two sets of
credentials, and for the most part uses the subjective credentials when
accessing current's creds.
There is, however, one exception: cap_capable(), and thus capable(), uses the
real/objective credentials of the target task, whether or not it is the current
task.
Ordinarily this doesn't matter, since usually the two cred pointers in current
point to the same set of creds. However, sys_faccessat() makes use of this
facility to override the credentials of the calling process to make its test,
without affecting the creds as seen from other processes.
One of the things sys_faccessat() does is to make an adjustment to the
effective capabilities mask, which cap_capable(), as it stands, then ignores.
The affected capability check is in generic_permission():
if (!(mask & MAY_EXEC) || execute_ok(inode))
if (capable(CAP_DAC_OVERRIDE))
return 0;
This change passes the set of credentials to be tested down into the commoncap
and SELinux code. The security functions called by capable() and
has_capability() select the appropriate set of credentials from the process
being checked.
This can be tested by compiling the following program from the XFS testsuite:
/*
* t_access_root.c - trivial test program to show permission bug.
*
* Written by Michael Kerrisk - copyright ownership not pursued.
* Sourced from: http://linux.derkeiler.com/Mailing-Lists/Kernel/2003-10/6030.html
*/
#include <limits.h>
#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>
#include <fcntl.h>
#include <sys/stat.h>
#define UID 500
#define GID 100
#define PERM 0
#define TESTPATH "/tmp/t_access"
static void
errExit(char *msg)
{
perror(msg);
exit(EXIT_FAILURE);
} /* errExit */
static void
accessTest(char *file, int mask, char *mstr)
{
printf("access(%s, %s) returns %d\n", file, mstr, access(file, mask));
} /* accessTest */
int
main(int argc, char *argv[])
{
int fd, perm, uid, gid;
char *testpath;
char cmd[PATH_MAX + 20];
testpath = (argc > 1) ? argv[1] : TESTPATH;
perm = (argc > 2) ? strtoul(argv[2], NULL, 8) : PERM;
uid = (argc > 3) ? atoi(argv[3]) : UID;
gid = (argc > 4) ? atoi(argv[4]) : GID;
unlink(testpath);
fd = open(testpath, O_RDWR | O_CREAT, 0);
if (fd == -1) errExit("open");
if (fchown(fd, uid, gid) == -1) errExit("fchown");
if (fchmod(fd, perm) == -1) errExit("fchmod");
close(fd);
snprintf(cmd, sizeof(cmd), "ls -l %s", testpath);
system(cmd);
if (seteuid(uid) == -1) errExit("seteuid");
accessTest(testpath, 0, "0");
accessTest(testpath, R_OK, "R_OK");
accessTest(testpath, W_OK, "W_OK");
accessTest(testpath, X_OK, "X_OK");
accessTest(testpath, R_OK | W_OK, "R_OK | W_OK");
accessTest(testpath, R_OK | X_OK, "R_OK | X_OK");
accessTest(testpath, W_OK | X_OK, "W_OK | X_OK");
accessTest(testpath, R_OK | W_OK | X_OK, "R_OK | W_OK | X_OK");
exit(EXIT_SUCCESS);
} /* main */
This can be run against an Ext3 filesystem as well as against an XFS
filesystem. If successful, it will show:
[root@andromeda src]# ./t_access_root /tmp/xxx 0 4043 4043
---------- 1 dhowells dhowells 0 2008-12-31 03:00 /tmp/xxx
access(/tmp/xxx, 0) returns 0
access(/tmp/xxx, R_OK) returns 0
access(/tmp/xxx, W_OK) returns 0
access(/tmp/xxx, X_OK) returns -1
access(/tmp/xxx, R_OK | W_OK) returns 0
access(/tmp/xxx, R_OK | X_OK) returns -1
access(/tmp/xxx, W_OK | X_OK) returns -1
access(/tmp/xxx, R_OK | W_OK | X_OK) returns -1
If unsuccessful, it will show:
[root@andromeda src]# ./t_access_root /tmp/xxx 0 4043 4043
---------- 1 dhowells dhowells 0 2008-12-31 02:56 /tmp/xxx
access(/tmp/xxx, 0) returns 0
access(/tmp/xxx, R_OK) returns -1
access(/tmp/xxx, W_OK) returns -1
access(/tmp/xxx, X_OK) returns -1
access(/tmp/xxx, R_OK | W_OK) returns -1
access(/tmp/xxx, R_OK | X_OK) returns -1
access(/tmp/xxx, W_OK | X_OK) returns -1
access(/tmp/xxx, R_OK | W_OK | X_OK) returns -1
I've also tested the fix with the SELinux and syscalls LTP testsuites.
Signed-off-by: David Howells <dhowells@redhat.com>
Tested-by: J. Bruce Fields <bfields@citi.umich.edu>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Signed-off-by: James Morris <jmorris@namei.org>
2009-01-06 22:27:01 +00:00
|
|
|
SECURITY_CAP_NOAUDIT);
|
2008-05-21 18:16:12 +00:00
|
|
|
if (!error)
|
|
|
|
error = security_sid_to_context_force(isec->sid, &context,
|
|
|
|
&size);
|
|
|
|
else
|
|
|
|
error = security_sid_to_context(isec->sid, &context, &size);
|
2008-02-05 06:29:39 +00:00
|
|
|
if (error)
|
|
|
|
return error;
|
|
|
|
error = size;
|
|
|
|
if (alloc) {
|
|
|
|
*buffer = context;
|
|
|
|
goto out_nofree;
|
|
|
|
}
|
|
|
|
kfree(context);
|
|
|
|
out_nofree:
|
|
|
|
return error;
|
2005-04-16 22:20:36 +00:00
|
|
|
}
|
|
|
|
|
|
|
|
static int selinux_inode_setsecurity(struct inode *inode, const char *name,
|
2008-04-17 17:17:49 +00:00
|
|
|
const void *value, size_t size, int flags)
|
2005-04-16 22:20:36 +00:00
|
|
|
{
|
|
|
|
struct inode_security_struct *isec = inode->i_security;
|
|
|
|
u32 newsid;
|
|
|
|
int rc;
|
|
|
|
|
|
|
|
if (strcmp(name, XATTR_SELINUX_SUFFIX))
|
|
|
|
return -EOPNOTSUPP;
|
|
|
|
|
|
|
|
if (!value || !size)
|
|
|
|
return -EACCES;
|
|
|
|
|
2014-03-07 11:44:19 +00:00
|
|
|
rc = security_context_to_sid((void *)value, size, &newsid, GFP_KERNEL);
|
2005-04-16 22:20:36 +00:00
|
|
|
if (rc)
|
|
|
|
return rc;
|
|
|
|
|
2013-05-22 16:50:44 +00:00
|
|
|
isec->sclass = inode_mode_to_security_class(inode->i_mode);
|
2005-04-16 22:20:36 +00:00
|
|
|
isec->sid = newsid;
|
2009-09-09 18:25:37 +00:00
|
|
|
isec->initialized = 1;
|
2005-04-16 22:20:36 +00:00
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
|
|
|
static int selinux_inode_listsecurity(struct inode *inode, char *buffer, size_t buffer_size)
|
|
|
|
{
|
|
|
|
const int len = sizeof(XATTR_NAME_SELINUX);
|
|
|
|
if (buffer && len <= buffer_size)
|
|
|
|
memcpy(buffer, XATTR_NAME_SELINUX, len);
|
|
|
|
return len;
|
|
|
|
}
|
|
|
|
|
2008-03-01 19:52:30 +00:00
|
|
|
static void selinux_inode_getsecid(const struct inode *inode, u32 *secid)
|
|
|
|
{
|
|
|
|
struct inode_security_struct *isec = inode->i_security;
|
|
|
|
*secid = isec->sid;
|
|
|
|
}
|
|
|
|
|
2005-04-16 22:20:36 +00:00
|
|
|
/* file security operations */
|
|
|
|
|
2007-09-14 00:27:07 +00:00
|
|
|
static int selinux_revalidate_file_permission(struct file *file, int mask)
|
2005-04-16 22:20:36 +00:00
|
|
|
{
|
2008-11-13 23:39:21 +00:00
|
|
|
const struct cred *cred = current_cred();
|
2013-01-23 22:07:38 +00:00
|
|
|
struct inode *inode = file_inode(file);
|
2005-04-16 22:20:36 +00:00
|
|
|
|
|
|
|
/* file_mask_to_av won't add FILE__WRITE if MAY_APPEND is set */
|
|
|
|
if ((file->f_flags & O_APPEND) && (mask & MAY_WRITE))
|
|
|
|
mask |= MAY_APPEND;
|
|
|
|
|
2009-03-27 21:10:34 +00:00
|
|
|
return file_has_perm(cred, file,
|
|
|
|
file_mask_to_av(inode->i_mode, mask));
|
2005-04-16 22:20:36 +00:00
|
|
|
}
|
|
|
|
|
2007-09-14 00:27:07 +00:00
|
|
|
static int selinux_file_permission(struct file *file, int mask)
|
|
|
|
{
|
2013-01-23 22:07:38 +00:00
|
|
|
struct inode *inode = file_inode(file);
|
2009-06-22 18:54:53 +00:00
|
|
|
struct file_security_struct *fsec = file->f_security;
|
|
|
|
struct inode_security_struct *isec = inode->i_security;
|
|
|
|
u32 sid = current_sid();
|
|
|
|
|
2009-03-27 21:10:34 +00:00
|
|
|
if (!mask)
|
2007-09-14 00:27:07 +00:00
|
|
|
/* No permission to check. Existence test. */
|
|
|
|
return 0;
|
|
|
|
|
2009-06-22 18:54:53 +00:00
|
|
|
if (sid == fsec->sid && fsec->isid == isec->sid &&
|
|
|
|
fsec->pseqno == avc_policy_seqno())
|
2012-04-04 17:45:40 +00:00
|
|
|
/* No change since file_open check. */
|
2009-06-22 18:54:53 +00:00
|
|
|
return 0;
|
|
|
|
|
2007-09-14 00:27:07 +00:00
|
|
|
return selinux_revalidate_file_permission(file, mask);
|
|
|
|
}
|
|
|
|
|
2005-04-16 22:20:36 +00:00
|
|
|
static int selinux_file_alloc_security(struct file *file)
|
|
|
|
{
|
|
|
|
return file_alloc_security(file);
|
|
|
|
}
|
|
|
|
|
|
|
|
static void selinux_file_free_security(struct file *file)
|
|
|
|
{
|
|
|
|
file_free_security(file);
|
|
|
|
}
|
|
|
|
|
|
|
|
static int selinux_file_ioctl(struct file *file, unsigned int cmd,
|
|
|
|
unsigned long arg)
|
|
|
|
{
|
2008-11-13 23:39:21 +00:00
|
|
|
const struct cred *cred = current_cred();
|
2011-02-25 20:39:20 +00:00
|
|
|
int error = 0;
|
2005-04-16 22:20:36 +00:00
|
|
|
|
2011-02-25 20:39:20 +00:00
|
|
|
switch (cmd) {
|
|
|
|
case FIONREAD:
|
|
|
|
/* fall through */
|
|
|
|
case FIBMAP:
|
|
|
|
/* fall through */
|
|
|
|
case FIGETBSZ:
|
|
|
|
/* fall through */
|
2012-03-23 20:04:05 +00:00
|
|
|
case FS_IOC_GETFLAGS:
|
2011-02-25 20:39:20 +00:00
|
|
|
/* fall through */
|
2012-03-23 20:04:05 +00:00
|
|
|
case FS_IOC_GETVERSION:
|
2011-02-25 20:39:20 +00:00
|
|
|
error = file_has_perm(cred, file, FILE__GETATTR);
|
|
|
|
break;
|
2005-04-16 22:20:36 +00:00
|
|
|
|
2012-03-23 20:04:05 +00:00
|
|
|
case FS_IOC_SETFLAGS:
|
2011-02-25 20:39:20 +00:00
|
|
|
/* fall through */
|
2012-03-23 20:04:05 +00:00
|
|
|
case FS_IOC_SETVERSION:
|
2011-02-25 20:39:20 +00:00
|
|
|
error = file_has_perm(cred, file, FILE__SETATTR);
|
|
|
|
break;
|
|
|
|
|
|
|
|
/* sys_ioctl() checks */
|
|
|
|
case FIONBIO:
|
|
|
|
/* fall through */
|
|
|
|
case FIOASYNC:
|
|
|
|
error = file_has_perm(cred, file, 0);
|
|
|
|
break;
|
2005-04-16 22:20:36 +00:00
|
|
|
|
2011-02-25 20:39:20 +00:00
|
|
|
case KDSKBENT:
|
|
|
|
case KDSKBSENT:
|
2012-01-03 17:25:14 +00:00
|
|
|
error = cred_has_capability(cred, CAP_SYS_TTY_CONFIG,
|
|
|
|
SECURITY_CAP_AUDIT);
|
2011-02-25 20:39:20 +00:00
|
|
|
break;
|
|
|
|
|
|
|
|
/* default case assumes that the command will go
|
|
|
|
* to the file's ioctl() function.
|
|
|
|
*/
|
|
|
|
default:
|
|
|
|
error = file_has_perm(cred, file, FILE__IOCTL);
|
|
|
|
}
|
|
|
|
return error;
|
2005-04-16 22:20:36 +00:00
|
|
|
}
|
|
|
|
|
selinux: generalize disabling of execmem for plt-in-heap archs
On Tue, 2010-04-27 at 11:47 -0700, David Miller wrote:
> From: "Tom \"spot\" Callaway" <tcallawa@redhat.com>
> Date: Tue, 27 Apr 2010 14:20:21 -0400
>
> > [root@apollo ~]$ cat /proc/2174/maps
> > 00010000-00014000 r-xp 00000000 fd:00 15466577
> > /sbin/mingetty
> > 00022000-00024000 rwxp 00002000 fd:00 15466577
> > /sbin/mingetty
> > 00024000-00046000 rwxp 00000000 00:00 0
> > [heap]
>
> SELINUX probably barfs on the executable heap, the PLT is in the HEAP
> just like powerpc32 and that's why VM_DATA_DEFAULT_FLAGS has to set
> both executable and writable.
>
> You also can't remove the CONFIG_PPC32 ifdefs in selinux, since
> because of the VM_DATA_DEFAULT_FLAGS setting used still in that arch,
> the heap will always have executable permission, just like sparc does.
> You have to support those binaries forever, whether you like it or not.
>
> Let's just replace the CONFIG_PPC32 ifdef in SELINUX with CONFIG_PPC32
> || CONFIG_SPARC as in Tom's original patch and let's be done with
> this.
>
> In fact I would go through all the arch/ header files and check the
> VM_DATA_DEFAULT_FLAGS settings and add the necessary new ifdefs to the
> SELINUX code so that other platforms don't have the pain of having to
> go through this process too.
To avoid maintaining per-arch ifdefs, it seems that we could just
directly use (VM_DATA_DEFAULT_FLAGS & VM_EXEC) as the basis for deciding
whether to enable or disable these checks. VM_DATA_DEFAULT_FLAGS isn't
constant on some architectures but instead depends on
current->personality, but we want this applied uniformly. So we'll just
use the initial task state to determine whether or not to enable these
checks.
Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov>
Acked-by: David S. Miller <davem@davemloft.net>
Signed-off-by: James Morris <jmorris@namei.org>
2010-04-28 19:57:57 +00:00
|
|
|
static int default_noexec;
|
|
|
|
|
2005-04-16 22:20:36 +00:00
|
|
|
static int file_map_prot_check(struct file *file, unsigned long prot, int shared)
|
|
|
|
{
|
2008-11-13 23:39:21 +00:00
|
|
|
const struct cred *cred = current_cred();
|
CRED: Inaugurate COW credentials
Inaugurate copy-on-write credentials management. This uses RCU to manage the
credentials pointer in the task_struct with respect to accesses by other tasks.
A process may only modify its own credentials, and so does not need locking to
access or modify its own credentials.
A mutex (cred_replace_mutex) is added to the task_struct to control the effect
of PTRACE_ATTACHED on credential calculations, particularly with respect to
execve().
With this patch, the contents of an active credentials struct may not be
changed directly; rather a new set of credentials must be prepared, modified
and committed using something like the following sequence of events:
struct cred *new = prepare_creds();
int ret = blah(new);
if (ret < 0) {
abort_creds(new);
return ret;
}
return commit_creds(new);
There are some exceptions to this rule: the keyrings pointed to by the active
credentials may be instantiated - keyrings violate the COW rule as managing
COW keyrings is tricky, given that it is possible for a task to directly alter
the keys in a keyring in use by another task.
To help enforce this, various pointers to sets of credentials, such as those in
the task_struct, are declared const. The purpose of this is compile-time
discouragement of altering credentials through those pointers. Once a set of
credentials has been made public through one of these pointers, it may not be
modified, except under special circumstances:
(1) Its reference count may incremented and decremented.
(2) The keyrings to which it points may be modified, but not replaced.
The only safe way to modify anything else is to create a replacement and commit
using the functions described in Documentation/credentials.txt (which will be
added by a later patch).
This patch and the preceding patches have been tested with the LTP SELinux
testsuite.
This patch makes several logical sets of alteration:
(1) execve().
This now prepares and commits credentials in various places in the
security code rather than altering the current creds directly.
(2) Temporary credential overrides.
do_coredump() and sys_faccessat() now prepare their own credentials and
temporarily override the ones currently on the acting thread, whilst
preventing interference from other threads by holding cred_replace_mutex
on the thread being dumped.
This will be replaced in a future patch by something that hands down the
credentials directly to the functions being called, rather than altering
the task's objective credentials.
(3) LSM interface.
A number of functions have been changed, added or removed:
(*) security_capset_check(), ->capset_check()
(*) security_capset_set(), ->capset_set()
Removed in favour of security_capset().
(*) security_capset(), ->capset()
New. This is passed a pointer to the new creds, a pointer to the old
creds and the proposed capability sets. It should fill in the new
creds or return an error. All pointers, barring the pointer to the
new creds, are now const.
(*) security_bprm_apply_creds(), ->bprm_apply_creds()
Changed; now returns a value, which will cause the process to be
killed if it's an error.
(*) security_task_alloc(), ->task_alloc_security()
Removed in favour of security_prepare_creds().
(*) security_cred_free(), ->cred_free()
New. Free security data attached to cred->security.
(*) security_prepare_creds(), ->cred_prepare()
New. Duplicate any security data attached to cred->security.
(*) security_commit_creds(), ->cred_commit()
New. Apply any security effects for the upcoming installation of new
security by commit_creds().
(*) security_task_post_setuid(), ->task_post_setuid()
Removed in favour of security_task_fix_setuid().
(*) security_task_fix_setuid(), ->task_fix_setuid()
Fix up the proposed new credentials for setuid(). This is used by
cap_set_fix_setuid() to implicitly adjust capabilities in line with
setuid() changes. Changes are made to the new credentials, rather
than the task itself as in security_task_post_setuid().
(*) security_task_reparent_to_init(), ->task_reparent_to_init()
Removed. Instead the task being reparented to init is referred
directly to init's credentials.
NOTE! This results in the loss of some state: SELinux's osid no
longer records the sid of the thread that forked it.
(*) security_key_alloc(), ->key_alloc()
(*) security_key_permission(), ->key_permission()
Changed. These now take cred pointers rather than task pointers to
refer to the security context.
(4) sys_capset().
This has been simplified and uses less locking. The LSM functions it
calls have been merged.
(5) reparent_to_kthreadd().
This gives the current thread the same credentials as init by simply using
commit_thread() to point that way.
(6) __sigqueue_alloc() and switch_uid()
__sigqueue_alloc() can't stop the target task from changing its creds
beneath it, so this function gets a reference to the currently applicable
user_struct which it then passes into the sigqueue struct it returns if
successful.
switch_uid() is now called from commit_creds(), and possibly should be
folded into that. commit_creds() should take care of protecting
__sigqueue_alloc().
(7) [sg]et[ug]id() and co and [sg]et_current_groups.
The set functions now all use prepare_creds(), commit_creds() and
abort_creds() to build and check a new set of credentials before applying
it.
security_task_set[ug]id() is called inside the prepared section. This
guarantees that nothing else will affect the creds until we've finished.
The calling of set_dumpable() has been moved into commit_creds().
Much of the functionality of set_user() has been moved into
commit_creds().
The get functions all simply access the data directly.
(8) security_task_prctl() and cap_task_prctl().
security_task_prctl() has been modified to return -ENOSYS if it doesn't
want to handle a function, or otherwise return the return value directly
rather than through an argument.
Additionally, cap_task_prctl() now prepares a new set of credentials, even
if it doesn't end up using it.
(9) Keyrings.
A number of changes have been made to the keyrings code:
(a) switch_uid_keyring(), copy_keys(), exit_keys() and suid_keys() have
all been dropped and built in to the credentials functions directly.
They may want separating out again later.
(b) key_alloc() and search_process_keyrings() now take a cred pointer
rather than a task pointer to specify the security context.
(c) copy_creds() gives a new thread within the same thread group a new
thread keyring if its parent had one, otherwise it discards the thread
keyring.
(d) The authorisation key now points directly to the credentials to extend
the search into rather pointing to the task that carries them.
(e) Installing thread, process or session keyrings causes a new set of
credentials to be created, even though it's not strictly necessary for
process or session keyrings (they're shared).
(10) Usermode helper.
The usermode helper code now carries a cred struct pointer in its
subprocess_info struct instead of a new session keyring pointer. This set
of credentials is derived from init_cred and installed on the new process
after it has been cloned.
call_usermodehelper_setup() allocates the new credentials and
call_usermodehelper_freeinfo() discards them if they haven't been used. A
special cred function (prepare_usermodeinfo_creds()) is provided
specifically for call_usermodehelper_setup() to call.
call_usermodehelper_setkeys() adjusts the credentials to sport the
supplied keyring as the new session keyring.
(11) SELinux.
SELinux has a number of changes, in addition to those to support the LSM
interface changes mentioned above:
(a) selinux_setprocattr() no longer does its check for whether the
current ptracer can access processes with the new SID inside the lock
that covers getting the ptracer's SID. Whilst this lock ensures that
the check is done with the ptracer pinned, the result is only valid
until the lock is released, so there's no point doing it inside the
lock.
(12) is_single_threaded().
This function has been extracted from selinux_setprocattr() and put into
a file of its own in the lib/ directory as join_session_keyring() now
wants to use it too.
The code in SELinux just checked to see whether a task shared mm_structs
with other tasks (CLONE_VM), but that isn't good enough. We really want
to know if they're part of the same thread group (CLONE_THREAD).
(13) nfsd.
The NFS server daemon now has to use the COW credentials to set the
credentials it is going to use. It really needs to pass the credentials
down to the functions it calls, but it can't do that until other patches
in this series have been applied.
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: James Morris <jmorris@namei.org>
Signed-off-by: James Morris <jmorris@namei.org>
2008-11-13 23:39:23 +00:00
|
|
|
int rc = 0;
|
2008-11-13 23:39:21 +00:00
|
|
|
|
selinux: generalize disabling of execmem for plt-in-heap archs
On Tue, 2010-04-27 at 11:47 -0700, David Miller wrote:
> From: "Tom \"spot\" Callaway" <tcallawa@redhat.com>
> Date: Tue, 27 Apr 2010 14:20:21 -0400
>
> > [root@apollo ~]$ cat /proc/2174/maps
> > 00010000-00014000 r-xp 00000000 fd:00 15466577
> > /sbin/mingetty
> > 00022000-00024000 rwxp 00002000 fd:00 15466577
> > /sbin/mingetty
> > 00024000-00046000 rwxp 00000000 00:00 0
> > [heap]
>
> SELINUX probably barfs on the executable heap, the PLT is in the HEAP
> just like powerpc32 and that's why VM_DATA_DEFAULT_FLAGS has to set
> both executable and writable.
>
> You also can't remove the CONFIG_PPC32 ifdefs in selinux, since
> because of the VM_DATA_DEFAULT_FLAGS setting used still in that arch,
> the heap will always have executable permission, just like sparc does.
> You have to support those binaries forever, whether you like it or not.
>
> Let's just replace the CONFIG_PPC32 ifdef in SELINUX with CONFIG_PPC32
> || CONFIG_SPARC as in Tom's original patch and let's be done with
> this.
>
> In fact I would go through all the arch/ header files and check the
> VM_DATA_DEFAULT_FLAGS settings and add the necessary new ifdefs to the
> SELINUX code so that other platforms don't have the pain of having to
> go through this process too.
To avoid maintaining per-arch ifdefs, it seems that we could just
directly use (VM_DATA_DEFAULT_FLAGS & VM_EXEC) as the basis for deciding
whether to enable or disable these checks. VM_DATA_DEFAULT_FLAGS isn't
constant on some architectures but instead depends on
current->personality, but we want this applied uniformly. So we'll just
use the initial task state to determine whether or not to enable these
checks.
Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov>
Acked-by: David S. Miller <davem@davemloft.net>
Signed-off-by: James Morris <jmorris@namei.org>
2010-04-28 19:57:57 +00:00
|
|
|
if (default_noexec &&
|
|
|
|
(prot & PROT_EXEC) && (!file || (!shared && (prot & PROT_WRITE)))) {
|
2005-04-16 22:20:36 +00:00
|
|
|
/*
|
|
|
|
* We are making executable an anonymous mapping or a
|
|
|
|
* private file mapping that will also be writable.
|
|
|
|
* This has an additional check.
|
|
|
|
*/
|
CRED: Inaugurate COW credentials
Inaugurate copy-on-write credentials management. This uses RCU to manage the
credentials pointer in the task_struct with respect to accesses by other tasks.
A process may only modify its own credentials, and so does not need locking to
access or modify its own credentials.
A mutex (cred_replace_mutex) is added to the task_struct to control the effect
of PTRACE_ATTACHED on credential calculations, particularly with respect to
execve().
With this patch, the contents of an active credentials struct may not be
changed directly; rather a new set of credentials must be prepared, modified
and committed using something like the following sequence of events:
struct cred *new = prepare_creds();
int ret = blah(new);
if (ret < 0) {
abort_creds(new);
return ret;
}
return commit_creds(new);
There are some exceptions to this rule: the keyrings pointed to by the active
credentials may be instantiated - keyrings violate the COW rule as managing
COW keyrings is tricky, given that it is possible for a task to directly alter
the keys in a keyring in use by another task.
To help enforce this, various pointers to sets of credentials, such as those in
the task_struct, are declared const. The purpose of this is compile-time
discouragement of altering credentials through those pointers. Once a set of
credentials has been made public through one of these pointers, it may not be
modified, except under special circumstances:
(1) Its reference count may incremented and decremented.
(2) The keyrings to which it points may be modified, but not replaced.
The only safe way to modify anything else is to create a replacement and commit
using the functions described in Documentation/credentials.txt (which will be
added by a later patch).
This patch and the preceding patches have been tested with the LTP SELinux
testsuite.
This patch makes several logical sets of alteration:
(1) execve().
This now prepares and commits credentials in various places in the
security code rather than altering the current creds directly.
(2) Temporary credential overrides.
do_coredump() and sys_faccessat() now prepare their own credentials and
temporarily override the ones currently on the acting thread, whilst
preventing interference from other threads by holding cred_replace_mutex
on the thread being dumped.
This will be replaced in a future patch by something that hands down the
credentials directly to the functions being called, rather than altering
the task's objective credentials.
(3) LSM interface.
A number of functions have been changed, added or removed:
(*) security_capset_check(), ->capset_check()
(*) security_capset_set(), ->capset_set()
Removed in favour of security_capset().
(*) security_capset(), ->capset()
New. This is passed a pointer to the new creds, a pointer to the old
creds and the proposed capability sets. It should fill in the new
creds or return an error. All pointers, barring the pointer to the
new creds, are now const.
(*) security_bprm_apply_creds(), ->bprm_apply_creds()
Changed; now returns a value, which will cause the process to be
killed if it's an error.
(*) security_task_alloc(), ->task_alloc_security()
Removed in favour of security_prepare_creds().
(*) security_cred_free(), ->cred_free()
New. Free security data attached to cred->security.
(*) security_prepare_creds(), ->cred_prepare()
New. Duplicate any security data attached to cred->security.
(*) security_commit_creds(), ->cred_commit()
New. Apply any security effects for the upcoming installation of new
security by commit_creds().
(*) security_task_post_setuid(), ->task_post_setuid()
Removed in favour of security_task_fix_setuid().
(*) security_task_fix_setuid(), ->task_fix_setuid()
Fix up the proposed new credentials for setuid(). This is used by
cap_set_fix_setuid() to implicitly adjust capabilities in line with
setuid() changes. Changes are made to the new credentials, rather
than the task itself as in security_task_post_setuid().
(*) security_task_reparent_to_init(), ->task_reparent_to_init()
Removed. Instead the task being reparented to init is referred
directly to init's credentials.
NOTE! This results in the loss of some state: SELinux's osid no
longer records the sid of the thread that forked it.
(*) security_key_alloc(), ->key_alloc()
(*) security_key_permission(), ->key_permission()
Changed. These now take cred pointers rather than task pointers to
refer to the security context.
(4) sys_capset().
This has been simplified and uses less locking. The LSM functions it
calls have been merged.
(5) reparent_to_kthreadd().
This gives the current thread the same credentials as init by simply using
commit_thread() to point that way.
(6) __sigqueue_alloc() and switch_uid()
__sigqueue_alloc() can't stop the target task from changing its creds
beneath it, so this function gets a reference to the currently applicable
user_struct which it then passes into the sigqueue struct it returns if
successful.
switch_uid() is now called from commit_creds(), and possibly should be
folded into that. commit_creds() should take care of protecting
__sigqueue_alloc().
(7) [sg]et[ug]id() and co and [sg]et_current_groups.
The set functions now all use prepare_creds(), commit_creds() and
abort_creds() to build and check a new set of credentials before applying
it.
security_task_set[ug]id() is called inside the prepared section. This
guarantees that nothing else will affect the creds until we've finished.
The calling of set_dumpable() has been moved into commit_creds().
Much of the functionality of set_user() has been moved into
commit_creds().
The get functions all simply access the data directly.
(8) security_task_prctl() and cap_task_prctl().
security_task_prctl() has been modified to return -ENOSYS if it doesn't
want to handle a function, or otherwise return the return value directly
rather than through an argument.
Additionally, cap_task_prctl() now prepares a new set of credentials, even
if it doesn't end up using it.
(9) Keyrings.
A number of changes have been made to the keyrings code:
(a) switch_uid_keyring(), copy_keys(), exit_keys() and suid_keys() have
all been dropped and built in to the credentials functions directly.
They may want separating out again later.
(b) key_alloc() and search_process_keyrings() now take a cred pointer
rather than a task pointer to specify the security context.
(c) copy_creds() gives a new thread within the same thread group a new
thread keyring if its parent had one, otherwise it discards the thread
keyring.
(d) The authorisation key now points directly to the credentials to extend
the search into rather pointing to the task that carries them.
(e) Installing thread, process or session keyrings causes a new set of
credentials to be created, even though it's not strictly necessary for
process or session keyrings (they're shared).
(10) Usermode helper.
The usermode helper code now carries a cred struct pointer in its
subprocess_info struct instead of a new session keyring pointer. This set
of credentials is derived from init_cred and installed on the new process
after it has been cloned.
call_usermodehelper_setup() allocates the new credentials and
call_usermodehelper_freeinfo() discards them if they haven't been used. A
special cred function (prepare_usermodeinfo_creds()) is provided
specifically for call_usermodehelper_setup() to call.
call_usermodehelper_setkeys() adjusts the credentials to sport the
supplied keyring as the new session keyring.
(11) SELinux.
SELinux has a number of changes, in addition to those to support the LSM
interface changes mentioned above:
(a) selinux_setprocattr() no longer does its check for whether the
current ptracer can access processes with the new SID inside the lock
that covers getting the ptracer's SID. Whilst this lock ensures that
the check is done with the ptracer pinned, the result is only valid
until the lock is released, so there's no point doing it inside the
lock.
(12) is_single_threaded().
This function has been extracted from selinux_setprocattr() and put into
a file of its own in the lib/ directory as join_session_keyring() now
wants to use it too.
The code in SELinux just checked to see whether a task shared mm_structs
with other tasks (CLONE_VM), but that isn't good enough. We really want
to know if they're part of the same thread group (CLONE_THREAD).
(13) nfsd.
The NFS server daemon now has to use the COW credentials to set the
credentials it is going to use. It really needs to pass the credentials
down to the functions it calls, but it can't do that until other patches
in this series have been applied.
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: James Morris <jmorris@namei.org>
Signed-off-by: James Morris <jmorris@namei.org>
2008-11-13 23:39:23 +00:00
|
|
|
rc = cred_has_perm(cred, cred, PROCESS__EXECMEM);
|
2005-04-16 22:20:36 +00:00
|
|
|
if (rc)
|
CRED: Inaugurate COW credentials
Inaugurate copy-on-write credentials management. This uses RCU to manage the
credentials pointer in the task_struct with respect to accesses by other tasks.
A process may only modify its own credentials, and so does not need locking to
access or modify its own credentials.
A mutex (cred_replace_mutex) is added to the task_struct to control the effect
of PTRACE_ATTACHED on credential calculations, particularly with respect to
execve().
With this patch, the contents of an active credentials struct may not be
changed directly; rather a new set of credentials must be prepared, modified
and committed using something like the following sequence of events:
struct cred *new = prepare_creds();
int ret = blah(new);
if (ret < 0) {
abort_creds(new);
return ret;
}
return commit_creds(new);
There are some exceptions to this rule: the keyrings pointed to by the active
credentials may be instantiated - keyrings violate the COW rule as managing
COW keyrings is tricky, given that it is possible for a task to directly alter
the keys in a keyring in use by another task.
To help enforce this, various pointers to sets of credentials, such as those in
the task_struct, are declared const. The purpose of this is compile-time
discouragement of altering credentials through those pointers. Once a set of
credentials has been made public through one of these pointers, it may not be
modified, except under special circumstances:
(1) Its reference count may incremented and decremented.
(2) The keyrings to which it points may be modified, but not replaced.
The only safe way to modify anything else is to create a replacement and commit
using the functions described in Documentation/credentials.txt (which will be
added by a later patch).
This patch and the preceding patches have been tested with the LTP SELinux
testsuite.
This patch makes several logical sets of alteration:
(1) execve().
This now prepares and commits credentials in various places in the
security code rather than altering the current creds directly.
(2) Temporary credential overrides.
do_coredump() and sys_faccessat() now prepare their own credentials and
temporarily override the ones currently on the acting thread, whilst
preventing interference from other threads by holding cred_replace_mutex
on the thread being dumped.
This will be replaced in a future patch by something that hands down the
credentials directly to the functions being called, rather than altering
the task's objective credentials.
(3) LSM interface.
A number of functions have been changed, added or removed:
(*) security_capset_check(), ->capset_check()
(*) security_capset_set(), ->capset_set()
Removed in favour of security_capset().
(*) security_capset(), ->capset()
New. This is passed a pointer to the new creds, a pointer to the old
creds and the proposed capability sets. It should fill in the new
creds or return an error. All pointers, barring the pointer to the
new creds, are now const.
(*) security_bprm_apply_creds(), ->bprm_apply_creds()
Changed; now returns a value, which will cause the process to be
killed if it's an error.
(*) security_task_alloc(), ->task_alloc_security()
Removed in favour of security_prepare_creds().
(*) security_cred_free(), ->cred_free()
New. Free security data attached to cred->security.
(*) security_prepare_creds(), ->cred_prepare()
New. Duplicate any security data attached to cred->security.
(*) security_commit_creds(), ->cred_commit()
New. Apply any security effects for the upcoming installation of new
security by commit_creds().
(*) security_task_post_setuid(), ->task_post_setuid()
Removed in favour of security_task_fix_setuid().
(*) security_task_fix_setuid(), ->task_fix_setuid()
Fix up the proposed new credentials for setuid(). This is used by
cap_set_fix_setuid() to implicitly adjust capabilities in line with
setuid() changes. Changes are made to the new credentials, rather
than the task itself as in security_task_post_setuid().
(*) security_task_reparent_to_init(), ->task_reparent_to_init()
Removed. Instead the task being reparented to init is referred
directly to init's credentials.
NOTE! This results in the loss of some state: SELinux's osid no
longer records the sid of the thread that forked it.
(*) security_key_alloc(), ->key_alloc()
(*) security_key_permission(), ->key_permission()
Changed. These now take cred pointers rather than task pointers to
refer to the security context.
(4) sys_capset().
This has been simplified and uses less locking. The LSM functions it
calls have been merged.
(5) reparent_to_kthreadd().
This gives the current thread the same credentials as init by simply using
commit_thread() to point that way.
(6) __sigqueue_alloc() and switch_uid()
__sigqueue_alloc() can't stop the target task from changing its creds
beneath it, so this function gets a reference to the currently applicable
user_struct which it then passes into the sigqueue struct it returns if
successful.
switch_uid() is now called from commit_creds(), and possibly should be
folded into that. commit_creds() should take care of protecting
__sigqueue_alloc().
(7) [sg]et[ug]id() and co and [sg]et_current_groups.
The set functions now all use prepare_creds(), commit_creds() and
abort_creds() to build and check a new set of credentials before applying
it.
security_task_set[ug]id() is called inside the prepared section. This
guarantees that nothing else will affect the creds until we've finished.
The calling of set_dumpable() has been moved into commit_creds().
Much of the functionality of set_user() has been moved into
commit_creds().
The get functions all simply access the data directly.
(8) security_task_prctl() and cap_task_prctl().
security_task_prctl() has been modified to return -ENOSYS if it doesn't
want to handle a function, or otherwise return the return value directly
rather than through an argument.
Additionally, cap_task_prctl() now prepares a new set of credentials, even
if it doesn't end up using it.
(9) Keyrings.
A number of changes have been made to the keyrings code:
(a) switch_uid_keyring(), copy_keys(), exit_keys() and suid_keys() have
all been dropped and built in to the credentials functions directly.
They may want separating out again later.
(b) key_alloc() and search_process_keyrings() now take a cred pointer
rather than a task pointer to specify the security context.
(c) copy_creds() gives a new thread within the same thread group a new
thread keyring if its parent had one, otherwise it discards the thread
keyring.
(d) The authorisation key now points directly to the credentials to extend
the search into rather pointing to the task that carries them.
(e) Installing thread, process or session keyrings causes a new set of
credentials to be created, even though it's not strictly necessary for
process or session keyrings (they're shared).
(10) Usermode helper.
The usermode helper code now carries a cred struct pointer in its
subprocess_info struct instead of a new session keyring pointer. This set
of credentials is derived from init_cred and installed on the new process
after it has been cloned.
call_usermodehelper_setup() allocates the new credentials and
call_usermodehelper_freeinfo() discards them if they haven't been used. A
special cred function (prepare_usermodeinfo_creds()) is provided
specifically for call_usermodehelper_setup() to call.
call_usermodehelper_setkeys() adjusts the credentials to sport the
supplied keyring as the new session keyring.
(11) SELinux.
SELinux has a number of changes, in addition to those to support the LSM
interface changes mentioned above:
(a) selinux_setprocattr() no longer does its check for whether the
current ptracer can access processes with the new SID inside the lock
that covers getting the ptracer's SID. Whilst this lock ensures that
the check is done with the ptracer pinned, the result is only valid
until the lock is released, so there's no point doing it inside the
lock.
(12) is_single_threaded().
This function has been extracted from selinux_setprocattr() and put into
a file of its own in the lib/ directory as join_session_keyring() now
wants to use it too.
The code in SELinux just checked to see whether a task shared mm_structs
with other tasks (CLONE_VM), but that isn't good enough. We really want
to know if they're part of the same thread group (CLONE_THREAD).
(13) nfsd.
The NFS server daemon now has to use the COW credentials to set the
credentials it is going to use. It really needs to pass the credentials
down to the functions it calls, but it can't do that until other patches
in this series have been applied.
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: James Morris <jmorris@namei.org>
Signed-off-by: James Morris <jmorris@namei.org>
2008-11-13 23:39:23 +00:00
|
|
|
goto error;
|
2005-04-16 22:20:36 +00:00
|
|
|
}
|
|
|
|
|
|
|
|
if (file) {
|
|
|
|
/* read access is always possible with a mapping */
|
|
|
|
u32 av = FILE__READ;
|
|
|
|
|
|
|
|
/* write access only matters if the mapping is shared */
|
|
|
|
if (shared && (prot & PROT_WRITE))
|
|
|
|
av |= FILE__WRITE;
|
|
|
|
|
|
|
|
if (prot & PROT_EXEC)
|
|
|
|
av |= FILE__EXECUTE;
|
|
|
|
|
2008-11-13 23:39:21 +00:00
|
|
|
return file_has_perm(cred, file, av);
|
2005-04-16 22:20:36 +00:00
|
|
|
}
|
CRED: Inaugurate COW credentials
Inaugurate copy-on-write credentials management. This uses RCU to manage the
credentials pointer in the task_struct with respect to accesses by other tasks.
A process may only modify its own credentials, and so does not need locking to
access or modify its own credentials.
A mutex (cred_replace_mutex) is added to the task_struct to control the effect
of PTRACE_ATTACHED on credential calculations, particularly with respect to
execve().
With this patch, the contents of an active credentials struct may not be
changed directly; rather a new set of credentials must be prepared, modified
and committed using something like the following sequence of events:
struct cred *new = prepare_creds();
int ret = blah(new);
if (ret < 0) {
abort_creds(new);
return ret;
}
return commit_creds(new);
There are some exceptions to this rule: the keyrings pointed to by the active
credentials may be instantiated - keyrings violate the COW rule as managing
COW keyrings is tricky, given that it is possible for a task to directly alter
the keys in a keyring in use by another task.
To help enforce this, various pointers to sets of credentials, such as those in
the task_struct, are declared const. The purpose of this is compile-time
discouragement of altering credentials through those pointers. Once a set of
credentials has been made public through one of these pointers, it may not be
modified, except under special circumstances:
(1) Its reference count may incremented and decremented.
(2) The keyrings to which it points may be modified, but not replaced.
The only safe way to modify anything else is to create a replacement and commit
using the functions described in Documentation/credentials.txt (which will be
added by a later patch).
This patch and the preceding patches have been tested with the LTP SELinux
testsuite.
This patch makes several logical sets of alteration:
(1) execve().
This now prepares and commits credentials in various places in the
security code rather than altering the current creds directly.
(2) Temporary credential overrides.
do_coredump() and sys_faccessat() now prepare their own credentials and
temporarily override the ones currently on the acting thread, whilst
preventing interference from other threads by holding cred_replace_mutex
on the thread being dumped.
This will be replaced in a future patch by something that hands down the
credentials directly to the functions being called, rather than altering
the task's objective credentials.
(3) LSM interface.
A number of functions have been changed, added or removed:
(*) security_capset_check(), ->capset_check()
(*) security_capset_set(), ->capset_set()
Removed in favour of security_capset().
(*) security_capset(), ->capset()
New. This is passed a pointer to the new creds, a pointer to the old
creds and the proposed capability sets. It should fill in the new
creds or return an error. All pointers, barring the pointer to the
new creds, are now const.
(*) security_bprm_apply_creds(), ->bprm_apply_creds()
Changed; now returns a value, which will cause the process to be
killed if it's an error.
(*) security_task_alloc(), ->task_alloc_security()
Removed in favour of security_prepare_creds().
(*) security_cred_free(), ->cred_free()
New. Free security data attached to cred->security.
(*) security_prepare_creds(), ->cred_prepare()
New. Duplicate any security data attached to cred->security.
(*) security_commit_creds(), ->cred_commit()
New. Apply any security effects for the upcoming installation of new
security by commit_creds().
(*) security_task_post_setuid(), ->task_post_setuid()
Removed in favour of security_task_fix_setuid().
(*) security_task_fix_setuid(), ->task_fix_setuid()
Fix up the proposed new credentials for setuid(). This is used by
cap_set_fix_setuid() to implicitly adjust capabilities in line with
setuid() changes. Changes are made to the new credentials, rather
than the task itself as in security_task_post_setuid().
(*) security_task_reparent_to_init(), ->task_reparent_to_init()
Removed. Instead the task being reparented to init is referred
directly to init's credentials.
NOTE! This results in the loss of some state: SELinux's osid no
longer records the sid of the thread that forked it.
(*) security_key_alloc(), ->key_alloc()
(*) security_key_permission(), ->key_permission()
Changed. These now take cred pointers rather than task pointers to
refer to the security context.
(4) sys_capset().
This has been simplified and uses less locking. The LSM functions it
calls have been merged.
(5) reparent_to_kthreadd().
This gives the current thread the same credentials as init by simply using
commit_thread() to point that way.
(6) __sigqueue_alloc() and switch_uid()
__sigqueue_alloc() can't stop the target task from changing its creds
beneath it, so this function gets a reference to the currently applicable
user_struct which it then passes into the sigqueue struct it returns if
successful.
switch_uid() is now called from commit_creds(), and possibly should be
folded into that. commit_creds() should take care of protecting
__sigqueue_alloc().
(7) [sg]et[ug]id() and co and [sg]et_current_groups.
The set functions now all use prepare_creds(), commit_creds() and
abort_creds() to build and check a new set of credentials before applying
it.
security_task_set[ug]id() is called inside the prepared section. This
guarantees that nothing else will affect the creds until we've finished.
The calling of set_dumpable() has been moved into commit_creds().
Much of the functionality of set_user() has been moved into
commit_creds().
The get functions all simply access the data directly.
(8) security_task_prctl() and cap_task_prctl().
security_task_prctl() has been modified to return -ENOSYS if it doesn't
want to handle a function, or otherwise return the return value directly
rather than through an argument.
Additionally, cap_task_prctl() now prepares a new set of credentials, even
if it doesn't end up using it.
(9) Keyrings.
A number of changes have been made to the keyrings code:
(a) switch_uid_keyring(), copy_keys(), exit_keys() and suid_keys() have
all been dropped and built in to the credentials functions directly.
They may want separating out again later.
(b) key_alloc() and search_process_keyrings() now take a cred pointer
rather than a task pointer to specify the security context.
(c) copy_creds() gives a new thread within the same thread group a new
thread keyring if its parent had one, otherwise it discards the thread
keyring.
(d) The authorisation key now points directly to the credentials to extend
the search into rather pointing to the task that carries them.
(e) Installing thread, process or session keyrings causes a new set of
credentials to be created, even though it's not strictly necessary for
process or session keyrings (they're shared).
(10) Usermode helper.
The usermode helper code now carries a cred struct pointer in its
subprocess_info struct instead of a new session keyring pointer. This set
of credentials is derived from init_cred and installed on the new process
after it has been cloned.
call_usermodehelper_setup() allocates the new credentials and
call_usermodehelper_freeinfo() discards them if they haven't been used. A
special cred function (prepare_usermodeinfo_creds()) is provided
specifically for call_usermodehelper_setup() to call.
call_usermodehelper_setkeys() adjusts the credentials to sport the
supplied keyring as the new session keyring.
(11) SELinux.
SELinux has a number of changes, in addition to those to support the LSM
interface changes mentioned above:
(a) selinux_setprocattr() no longer does its check for whether the
current ptracer can access processes with the new SID inside the lock
that covers getting the ptracer's SID. Whilst this lock ensures that
the check is done with the ptracer pinned, the result is only valid
until the lock is released, so there's no point doing it inside the
lock.
(12) is_single_threaded().
This function has been extracted from selinux_setprocattr() and put into
a file of its own in the lib/ directory as join_session_keyring() now
wants to use it too.
The code in SELinux just checked to see whether a task shared mm_structs
with other tasks (CLONE_VM), but that isn't good enough. We really want
to know if they're part of the same thread group (CLONE_THREAD).
(13) nfsd.
The NFS server daemon now has to use the COW credentials to set the
credentials it is going to use. It really needs to pass the credentials
down to the functions it calls, but it can't do that until other patches
in this series have been applied.
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: James Morris <jmorris@namei.org>
Signed-off-by: James Morris <jmorris@namei.org>
2008-11-13 23:39:23 +00:00
|
|
|
|
|
|
|
error:
|
|
|
|
return rc;
|
2005-04-16 22:20:36 +00:00
|
|
|
}
|
|
|
|
|
2012-05-30 17:30:51 +00:00
|
|
|
static int selinux_mmap_addr(unsigned long addr)
|
2005-04-16 22:20:36 +00:00
|
|
|
{
|
2014-03-19 20:46:11 +00:00
|
|
|
int rc;
|
|
|
|
|
|
|
|
/* do DAC check on address space usage */
|
|
|
|
rc = cap_mmap_addr(addr);
|
|
|
|
if (rc)
|
|
|
|
return rc;
|
2005-04-16 22:20:36 +00:00
|
|
|
|
2009-07-31 16:54:11 +00:00
|
|
|
if (addr < CONFIG_LSM_MMAP_MIN_ADDR) {
|
2014-03-19 20:46:11 +00:00
|
|
|
u32 sid = current_sid();
|
2007-06-28 19:55:21 +00:00
|
|
|
rc = avc_has_perm(sid, sid, SECCLASS_MEMPROTECT,
|
|
|
|
MEMPROTECT__MMAP_ZERO, NULL);
|
2009-07-31 16:54:05 +00:00
|
|
|
}
|
|
|
|
|
2014-03-19 20:46:11 +00:00
|
|
|
return rc;
|
2012-05-30 17:30:51 +00:00
|
|
|
}
|
2005-04-16 22:20:36 +00:00
|
|
|
|
2012-05-30 17:30:51 +00:00
|
|
|
static int selinux_mmap_file(struct file *file, unsigned long reqprot,
|
|
|
|
unsigned long prot, unsigned long flags)
|
|
|
|
{
|
2005-04-16 22:20:36 +00:00
|
|
|
if (selinux_checkreqprot)
|
|
|
|
prot = reqprot;
|
|
|
|
|
|
|
|
return file_map_prot_check(file, prot,
|
|
|
|
(flags & MAP_TYPE) == MAP_SHARED);
|
|
|
|
}
|
|
|
|
|
|
|
|
static int selinux_file_mprotect(struct vm_area_struct *vma,
|
|
|
|
unsigned long reqprot,
|
|
|
|
unsigned long prot)
|
|
|
|
{
|
2008-11-13 23:39:21 +00:00
|
|
|
const struct cred *cred = current_cred();
|
2005-04-16 22:20:36 +00:00
|
|
|
|
|
|
|
if (selinux_checkreqprot)
|
|
|
|
prot = reqprot;
|
|
|
|
|
selinux: generalize disabling of execmem for plt-in-heap archs
On Tue, 2010-04-27 at 11:47 -0700, David Miller wrote:
> From: "Tom \"spot\" Callaway" <tcallawa@redhat.com>
> Date: Tue, 27 Apr 2010 14:20:21 -0400
>
> > [root@apollo ~]$ cat /proc/2174/maps
> > 00010000-00014000 r-xp 00000000 fd:00 15466577
> > /sbin/mingetty
> > 00022000-00024000 rwxp 00002000 fd:00 15466577
> > /sbin/mingetty
> > 00024000-00046000 rwxp 00000000 00:00 0
> > [heap]
>
> SELINUX probably barfs on the executable heap, the PLT is in the HEAP
> just like powerpc32 and that's why VM_DATA_DEFAULT_FLAGS has to set
> both executable and writable.
>
> You also can't remove the CONFIG_PPC32 ifdefs in selinux, since
> because of the VM_DATA_DEFAULT_FLAGS setting used still in that arch,
> the heap will always have executable permission, just like sparc does.
> You have to support those binaries forever, whether you like it or not.
>
> Let's just replace the CONFIG_PPC32 ifdef in SELINUX with CONFIG_PPC32
> || CONFIG_SPARC as in Tom's original patch and let's be done with
> this.
>
> In fact I would go through all the arch/ header files and check the
> VM_DATA_DEFAULT_FLAGS settings and add the necessary new ifdefs to the
> SELINUX code so that other platforms don't have the pain of having to
> go through this process too.
To avoid maintaining per-arch ifdefs, it seems that we could just
directly use (VM_DATA_DEFAULT_FLAGS & VM_EXEC) as the basis for deciding
whether to enable or disable these checks. VM_DATA_DEFAULT_FLAGS isn't
constant on some architectures but instead depends on
current->personality, but we want this applied uniformly. So we'll just
use the initial task state to determine whether or not to enable these
checks.
Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov>
Acked-by: David S. Miller <davem@davemloft.net>
Signed-off-by: James Morris <jmorris@namei.org>
2010-04-28 19:57:57 +00:00
|
|
|
if (default_noexec &&
|
|
|
|
(prot & PROT_EXEC) && !(vma->vm_flags & VM_EXEC)) {
|
2009-01-29 01:19:51 +00:00
|
|
|
int rc = 0;
|
2006-02-01 11:05:54 +00:00
|
|
|
if (vma->vm_start >= vma->vm_mm->start_brk &&
|
|
|
|
vma->vm_end <= vma->vm_mm->brk) {
|
CRED: Inaugurate COW credentials
Inaugurate copy-on-write credentials management. This uses RCU to manage the
credentials pointer in the task_struct with respect to accesses by other tasks.
A process may only modify its own credentials, and so does not need locking to
access or modify its own credentials.
A mutex (cred_replace_mutex) is added to the task_struct to control the effect
of PTRACE_ATTACHED on credential calculations, particularly with respect to
execve().
With this patch, the contents of an active credentials struct may not be
changed directly; rather a new set of credentials must be prepared, modified
and committed using something like the following sequence of events:
struct cred *new = prepare_creds();
int ret = blah(new);
if (ret < 0) {
abort_creds(new);
return ret;
}
return commit_creds(new);
There are some exceptions to this rule: the keyrings pointed to by the active
credentials may be instantiated - keyrings violate the COW rule as managing
COW keyrings is tricky, given that it is possible for a task to directly alter
the keys in a keyring in use by another task.
To help enforce this, various pointers to sets of credentials, such as those in
the task_struct, are declared const. The purpose of this is compile-time
discouragement of altering credentials through those pointers. Once a set of
credentials has been made public through one of these pointers, it may not be
modified, except under special circumstances:
(1) Its reference count may incremented and decremented.
(2) The keyrings to which it points may be modified, but not replaced.
The only safe way to modify anything else is to create a replacement and commit
using the functions described in Documentation/credentials.txt (which will be
added by a later patch).
This patch and the preceding patches have been tested with the LTP SELinux
testsuite.
This patch makes several logical sets of alteration:
(1) execve().
This now prepares and commits credentials in various places in the
security code rather than altering the current creds directly.
(2) Temporary credential overrides.
do_coredump() and sys_faccessat() now prepare their own credentials and
temporarily override the ones currently on the acting thread, whilst
preventing interference from other threads by holding cred_replace_mutex
on the thread being dumped.
This will be replaced in a future patch by something that hands down the
credentials directly to the functions being called, rather than altering
the task's objective credentials.
(3) LSM interface.
A number of functions have been changed, added or removed:
(*) security_capset_check(), ->capset_check()
(*) security_capset_set(), ->capset_set()
Removed in favour of security_capset().
(*) security_capset(), ->capset()
New. This is passed a pointer to the new creds, a pointer to the old
creds and the proposed capability sets. It should fill in the new
creds or return an error. All pointers, barring the pointer to the
new creds, are now const.
(*) security_bprm_apply_creds(), ->bprm_apply_creds()
Changed; now returns a value, which will cause the process to be
killed if it's an error.
(*) security_task_alloc(), ->task_alloc_security()
Removed in favour of security_prepare_creds().
(*) security_cred_free(), ->cred_free()
New. Free security data attached to cred->security.
(*) security_prepare_creds(), ->cred_prepare()
New. Duplicate any security data attached to cred->security.
(*) security_commit_creds(), ->cred_commit()
New. Apply any security effects for the upcoming installation of new
security by commit_creds().
(*) security_task_post_setuid(), ->task_post_setuid()
Removed in favour of security_task_fix_setuid().
(*) security_task_fix_setuid(), ->task_fix_setuid()
Fix up the proposed new credentials for setuid(). This is used by
cap_set_fix_setuid() to implicitly adjust capabilities in line with
setuid() changes. Changes are made to the new credentials, rather
than the task itself as in security_task_post_setuid().
(*) security_task_reparent_to_init(), ->task_reparent_to_init()
Removed. Instead the task being reparented to init is referred
directly to init's credentials.
NOTE! This results in the loss of some state: SELinux's osid no
longer records the sid of the thread that forked it.
(*) security_key_alloc(), ->key_alloc()
(*) security_key_permission(), ->key_permission()
Changed. These now take cred pointers rather than task pointers to
refer to the security context.
(4) sys_capset().
This has been simplified and uses less locking. The LSM functions it
calls have been merged.
(5) reparent_to_kthreadd().
This gives the current thread the same credentials as init by simply using
commit_thread() to point that way.
(6) __sigqueue_alloc() and switch_uid()
__sigqueue_alloc() can't stop the target task from changing its creds
beneath it, so this function gets a reference to the currently applicable
user_struct which it then passes into the sigqueue struct it returns if
successful.
switch_uid() is now called from commit_creds(), and possibly should be
folded into that. commit_creds() should take care of protecting
__sigqueue_alloc().
(7) [sg]et[ug]id() and co and [sg]et_current_groups.
The set functions now all use prepare_creds(), commit_creds() and
abort_creds() to build and check a new set of credentials before applying
it.
security_task_set[ug]id() is called inside the prepared section. This
guarantees that nothing else will affect the creds until we've finished.
The calling of set_dumpable() has been moved into commit_creds().
Much of the functionality of set_user() has been moved into
commit_creds().
The get functions all simply access the data directly.
(8) security_task_prctl() and cap_task_prctl().
security_task_prctl() has been modified to return -ENOSYS if it doesn't
want to handle a function, or otherwise return the return value directly
rather than through an argument.
Additionally, cap_task_prctl() now prepares a new set of credentials, even
if it doesn't end up using it.
(9) Keyrings.
A number of changes have been made to the keyrings code:
(a) switch_uid_keyring(), copy_keys(), exit_keys() and suid_keys() have
all been dropped and built in to the credentials functions directly.
They may want separating out again later.
(b) key_alloc() and search_process_keyrings() now take a cred pointer
rather than a task pointer to specify the security context.
(c) copy_creds() gives a new thread within the same thread group a new
thread keyring if its parent had one, otherwise it discards the thread
keyring.
(d) The authorisation key now points directly to the credentials to extend
the search into rather pointing to the task that carries them.
(e) Installing thread, process or session keyrings causes a new set of
credentials to be created, even though it's not strictly necessary for
process or session keyrings (they're shared).
(10) Usermode helper.
The usermode helper code now carries a cred struct pointer in its
subprocess_info struct instead of a new session keyring pointer. This set
of credentials is derived from init_cred and installed on the new process
after it has been cloned.
call_usermodehelper_setup() allocates the new credentials and
call_usermodehelper_freeinfo() discards them if they haven't been used. A
special cred function (prepare_usermodeinfo_creds()) is provided
specifically for call_usermodehelper_setup() to call.
call_usermodehelper_setkeys() adjusts the credentials to sport the
supplied keyring as the new session keyring.
(11) SELinux.
SELinux has a number of changes, in addition to those to support the LSM
interface changes mentioned above:
(a) selinux_setprocattr() no longer does its check for whether the
current ptracer can access processes with the new SID inside the lock
that covers getting the ptracer's SID. Whilst this lock ensures that
the check is done with the ptracer pinned, the result is only valid
until the lock is released, so there's no point doing it inside the
lock.
(12) is_single_threaded().
This function has been extracted from selinux_setprocattr() and put into
a file of its own in the lib/ directory as join_session_keyring() now
wants to use it too.
The code in SELinux just checked to see whether a task shared mm_structs
with other tasks (CLONE_VM), but that isn't good enough. We really want
to know if they're part of the same thread group (CLONE_THREAD).
(13) nfsd.
The NFS server daemon now has to use the COW credentials to set the
credentials it is going to use. It really needs to pass the credentials
down to the functions it calls, but it can't do that until other patches
in this series have been applied.
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: James Morris <jmorris@namei.org>
Signed-off-by: James Morris <jmorris@namei.org>
2008-11-13 23:39:23 +00:00
|
|
|
rc = cred_has_perm(cred, cred, PROCESS__EXECHEAP);
|
2006-02-01 11:05:54 +00:00
|
|
|
} else if (!vma->vm_file &&
|
|
|
|
vma->vm_start <= vma->vm_mm->start_stack &&
|
|
|
|
vma->vm_end >= vma->vm_mm->start_stack) {
|
2008-11-13 23:39:26 +00:00
|
|
|
rc = current_has_perm(current, PROCESS__EXECSTACK);
|
2006-02-01 11:05:54 +00:00
|
|
|
} else if (vma->vm_file && vma->anon_vma) {
|
|
|
|
/*
|
|
|
|
* We are making executable a file mapping that has
|
|
|
|
* had some COW done. Since pages might have been
|
|
|
|
* written, check ability to execute the possibly
|
|
|
|
* modified content. This typically should only
|
|
|
|
* occur for text relocations.
|
|
|
|
*/
|
CRED: Inaugurate COW credentials
Inaugurate copy-on-write credentials management. This uses RCU to manage the
credentials pointer in the task_struct with respect to accesses by other tasks.
A process may only modify its own credentials, and so does not need locking to
access or modify its own credentials.
A mutex (cred_replace_mutex) is added to the task_struct to control the effect
of PTRACE_ATTACHED on credential calculations, particularly with respect to
execve().
With this patch, the contents of an active credentials struct may not be
changed directly; rather a new set of credentials must be prepared, modified
and committed using something like the following sequence of events:
struct cred *new = prepare_creds();
int ret = blah(new);
if (ret < 0) {
abort_creds(new);
return ret;
}
return commit_creds(new);
There are some exceptions to this rule: the keyrings pointed to by the active
credentials may be instantiated - keyrings violate the COW rule as managing
COW keyrings is tricky, given that it is possible for a task to directly alter
the keys in a keyring in use by another task.
To help enforce this, various pointers to sets of credentials, such as those in
the task_struct, are declared const. The purpose of this is compile-time
discouragement of altering credentials through those pointers. Once a set of
credentials has been made public through one of these pointers, it may not be
modified, except under special circumstances:
(1) Its reference count may incremented and decremented.
(2) The keyrings to which it points may be modified, but not replaced.
The only safe way to modify anything else is to create a replacement and commit
using the functions described in Documentation/credentials.txt (which will be
added by a later patch).
This patch and the preceding patches have been tested with the LTP SELinux
testsuite.
This patch makes several logical sets of alteration:
(1) execve().
This now prepares and commits credentials in various places in the
security code rather than altering the current creds directly.
(2) Temporary credential overrides.
do_coredump() and sys_faccessat() now prepare their own credentials and
temporarily override the ones currently on the acting thread, whilst
preventing interference from other threads by holding cred_replace_mutex
on the thread being dumped.
This will be replaced in a future patch by something that hands down the
credentials directly to the functions being called, rather than altering
the task's objective credentials.
(3) LSM interface.
A number of functions have been changed, added or removed:
(*) security_capset_check(), ->capset_check()
(*) security_capset_set(), ->capset_set()
Removed in favour of security_capset().
(*) security_capset(), ->capset()
New. This is passed a pointer to the new creds, a pointer to the old
creds and the proposed capability sets. It should fill in the new
creds or return an error. All pointers, barring the pointer to the
new creds, are now const.
(*) security_bprm_apply_creds(), ->bprm_apply_creds()
Changed; now returns a value, which will cause the process to be
killed if it's an error.
(*) security_task_alloc(), ->task_alloc_security()
Removed in favour of security_prepare_creds().
(*) security_cred_free(), ->cred_free()
New. Free security data attached to cred->security.
(*) security_prepare_creds(), ->cred_prepare()
New. Duplicate any security data attached to cred->security.
(*) security_commit_creds(), ->cred_commit()
New. Apply any security effects for the upcoming installation of new
security by commit_creds().
(*) security_task_post_setuid(), ->task_post_setuid()
Removed in favour of security_task_fix_setuid().
(*) security_task_fix_setuid(), ->task_fix_setuid()
Fix up the proposed new credentials for setuid(). This is used by
cap_set_fix_setuid() to implicitly adjust capabilities in line with
setuid() changes. Changes are made to the new credentials, rather
than the task itself as in security_task_post_setuid().
(*) security_task_reparent_to_init(), ->task_reparent_to_init()
Removed. Instead the task being reparented to init is referred
directly to init's credentials.
NOTE! This results in the loss of some state: SELinux's osid no
longer records the sid of the thread that forked it.
(*) security_key_alloc(), ->key_alloc()
(*) security_key_permission(), ->key_permission()
Changed. These now take cred pointers rather than task pointers to
refer to the security context.
(4) sys_capset().
This has been simplified and uses less locking. The LSM functions it
calls have been merged.
(5) reparent_to_kthreadd().
This gives the current thread the same credentials as init by simply using
commit_thread() to point that way.
(6) __sigqueue_alloc() and switch_uid()
__sigqueue_alloc() can't stop the target task from changing its creds
beneath it, so this function gets a reference to the currently applicable
user_struct which it then passes into the sigqueue struct it returns if
successful.
switch_uid() is now called from commit_creds(), and possibly should be
folded into that. commit_creds() should take care of protecting
__sigqueue_alloc().
(7) [sg]et[ug]id() and co and [sg]et_current_groups.
The set functions now all use prepare_creds(), commit_creds() and
abort_creds() to build and check a new set of credentials before applying
it.
security_task_set[ug]id() is called inside the prepared section. This
guarantees that nothing else will affect the creds until we've finished.
The calling of set_dumpable() has been moved into commit_creds().
Much of the functionality of set_user() has been moved into
commit_creds().
The get functions all simply access the data directly.
(8) security_task_prctl() and cap_task_prctl().
security_task_prctl() has been modified to return -ENOSYS if it doesn't
want to handle a function, or otherwise return the return value directly
rather than through an argument.
Additionally, cap_task_prctl() now prepares a new set of credentials, even
if it doesn't end up using it.
(9) Keyrings.
A number of changes have been made to the keyrings code:
(a) switch_uid_keyring(), copy_keys(), exit_keys() and suid_keys() have
all been dropped and built in to the credentials functions directly.
They may want separating out again later.
(b) key_alloc() and search_process_keyrings() now take a cred pointer
rather than a task pointer to specify the security context.
(c) copy_creds() gives a new thread within the same thread group a new
thread keyring if its parent had one, otherwise it discards the thread
keyring.
(d) The authorisation key now points directly to the credentials to extend
the search into rather pointing to the task that carries them.
(e) Installing thread, process or session keyrings causes a new set of
credentials to be created, even though it's not strictly necessary for
process or session keyrings (they're shared).
(10) Usermode helper.
The usermode helper code now carries a cred struct pointer in its
subprocess_info struct instead of a new session keyring pointer. This set
of credentials is derived from init_cred and installed on the new process
after it has been cloned.
call_usermodehelper_setup() allocates the new credentials and
call_usermodehelper_freeinfo() discards them if they haven't been used. A
special cred function (prepare_usermodeinfo_creds()) is provided
specifically for call_usermodehelper_setup() to call.
call_usermodehelper_setkeys() adjusts the credentials to sport the
supplied keyring as the new session keyring.
(11) SELinux.
SELinux has a number of changes, in addition to those to support the LSM
interface changes mentioned above:
(a) selinux_setprocattr() no longer does its check for whether the
current ptracer can access processes with the new SID inside the lock
that covers getting the ptracer's SID. Whilst this lock ensures that
the check is done with the ptracer pinned, the result is only valid
until the lock is released, so there's no point doing it inside the
lock.
(12) is_single_threaded().
This function has been extracted from selinux_setprocattr() and put into
a file of its own in the lib/ directory as join_session_keyring() now
wants to use it too.
The code in SELinux just checked to see whether a task shared mm_structs
with other tasks (CLONE_VM), but that isn't good enough. We really want
to know if they're part of the same thread group (CLONE_THREAD).
(13) nfsd.
The NFS server daemon now has to use the COW credentials to set the
credentials it is going to use. It really needs to pass the credentials
down to the functions it calls, but it can't do that until other patches
in this series have been applied.
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: James Morris <jmorris@namei.org>
Signed-off-by: James Morris <jmorris@namei.org>
2008-11-13 23:39:23 +00:00
|
|
|
rc = file_has_perm(cred, vma->vm_file, FILE__EXECMOD);
|
2006-02-01 11:05:54 +00:00
|
|
|
}
|
2005-06-25 21:54:34 +00:00
|
|
|
if (rc)
|
|
|
|
return rc;
|
|
|
|
}
|
2005-04-16 22:20:36 +00:00
|
|
|
|
|
|
|
return file_map_prot_check(vma->vm_file, prot, vma->vm_flags&VM_SHARED);
|
|
|
|
}
|
|
|
|
|
|
|
|
static int selinux_file_lock(struct file *file, unsigned int cmd)
|
|
|
|
{
|
2008-11-13 23:39:21 +00:00
|
|
|
const struct cred *cred = current_cred();
|
|
|
|
|
|
|
|
return file_has_perm(cred, file, FILE__LOCK);
|
2005-04-16 22:20:36 +00:00
|
|
|
}
|
|
|
|
|
|
|
|
static int selinux_file_fcntl(struct file *file, unsigned int cmd,
|
|
|
|
unsigned long arg)
|
|
|
|
{
|
2008-11-13 23:39:21 +00:00
|
|
|
const struct cred *cred = current_cred();
|
2005-04-16 22:20:36 +00:00
|
|
|
int err = 0;
|
|
|
|
|
|
|
|
switch (cmd) {
|
2008-04-17 17:17:49 +00:00
|
|
|
case F_SETFL:
|
|
|
|
if ((file->f_flags & O_APPEND) && !(arg & O_APPEND)) {
|
2008-11-13 23:39:21 +00:00
|
|
|
err = file_has_perm(cred, file, FILE__WRITE);
|
2005-04-16 22:20:36 +00:00
|
|
|
break;
|
2008-04-17 17:17:49 +00:00
|
|
|
}
|
|
|
|
/* fall through */
|
|
|
|
case F_SETOWN:
|
|
|
|
case F_SETSIG:
|
|
|
|
case F_GETFL:
|
|
|
|
case F_GETOWN:
|
|
|
|
case F_GETSIG:
|
2012-07-30 21:43:00 +00:00
|
|
|
case F_GETOWNER_UIDS:
|
2008-04-17 17:17:49 +00:00
|
|
|
/* Just check FD__USE permission */
|
2008-11-13 23:39:21 +00:00
|
|
|
err = file_has_perm(cred, file, 0);
|
2008-04-17 17:17:49 +00:00
|
|
|
break;
|
|
|
|
case F_GETLK:
|
|
|
|
case F_SETLK:
|
|
|
|
case F_SETLKW:
|
2014-04-22 12:23:58 +00:00
|
|
|
case F_OFD_GETLK:
|
|
|
|
case F_OFD_SETLK:
|
|
|
|
case F_OFD_SETLKW:
|
2005-04-16 22:20:36 +00:00
|
|
|
#if BITS_PER_LONG == 32
|
2008-04-17 17:17:49 +00:00
|
|
|
case F_GETLK64:
|
|
|
|
case F_SETLK64:
|
|
|
|
case F_SETLKW64:
|
2005-04-16 22:20:36 +00:00
|
|
|
#endif
|
2008-11-13 23:39:21 +00:00
|
|
|
err = file_has_perm(cred, file, FILE__LOCK);
|
2008-04-17 17:17:49 +00:00
|
|
|
break;
|
2005-04-16 22:20:36 +00:00
|
|
|
}
|
|
|
|
|
|
|
|
return err;
|
|
|
|
}
|
|
|
|
|
|
|
|
static int selinux_file_set_fowner(struct file *file)
|
|
|
|
{
|
|
|
|
struct file_security_struct *fsec;
|
|
|
|
|
|
|
|
fsec = file->f_security;
|
2008-11-13 23:39:19 +00:00
|
|
|
fsec->fown_sid = current_sid();
|
2005-04-16 22:20:36 +00:00
|
|
|
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
|
|
|
static int selinux_file_send_sigiotask(struct task_struct *tsk,
|
|
|
|
struct fown_struct *fown, int signum)
|
|
|
|
{
|
2008-04-17 17:17:49 +00:00
|
|
|
struct file *file;
|
2009-05-04 19:43:18 +00:00
|
|
|
u32 sid = task_sid(tsk);
|
2005-04-16 22:20:36 +00:00
|
|
|
u32 perm;
|
|
|
|
struct file_security_struct *fsec;
|
|
|
|
|
|
|
|
/* struct fown_struct is never outside the context of a struct file */
|
2008-04-17 17:17:49 +00:00
|
|
|
file = container_of(fown, struct file, f_owner);
|
2005-04-16 22:20:36 +00:00
|
|
|
|
|
|
|
fsec = file->f_security;
|
|
|
|
|
|
|
|
if (!signum)
|
|
|
|
perm = signal_to_av(SIGIO); /* as per send_sigio_to_task */
|
|
|
|
else
|
|
|
|
perm = signal_to_av(signum);
|
|
|
|
|
2008-11-13 23:39:19 +00:00
|
|
|
return avc_has_perm(fsec->fown_sid, sid,
|
2005-04-16 22:20:36 +00:00
|
|
|
SECCLASS_PROCESS, perm, NULL);
|
|
|
|
}
|
|
|
|
|
|
|
|
static int selinux_file_receive(struct file *file)
|
|
|
|
{
|
2008-11-13 23:39:21 +00:00
|
|
|
const struct cred *cred = current_cred();
|
|
|
|
|
|
|
|
return file_has_perm(cred, file, file_to_av(file));
|
2005-04-16 22:20:36 +00:00
|
|
|
}
|
|
|
|
|
2012-04-04 17:45:40 +00:00
|
|
|
static int selinux_file_open(struct file *file, const struct cred *cred)
|
2007-09-14 00:27:07 +00:00
|
|
|
{
|
|
|
|
struct file_security_struct *fsec;
|
|
|
|
struct inode_security_struct *isec;
|
CRED: Inaugurate COW credentials
Inaugurate copy-on-write credentials management. This uses RCU to manage the
credentials pointer in the task_struct with respect to accesses by other tasks.
A process may only modify its own credentials, and so does not need locking to
access or modify its own credentials.
A mutex (cred_replace_mutex) is added to the task_struct to control the effect
of PTRACE_ATTACHED on credential calculations, particularly with respect to
execve().
With this patch, the contents of an active credentials struct may not be
changed directly; rather a new set of credentials must be prepared, modified
and committed using something like the following sequence of events:
struct cred *new = prepare_creds();
int ret = blah(new);
if (ret < 0) {
abort_creds(new);
return ret;
}
return commit_creds(new);
There are some exceptions to this rule: the keyrings pointed to by the active
credentials may be instantiated - keyrings violate the COW rule as managing
COW keyrings is tricky, given that it is possible for a task to directly alter
the keys in a keyring in use by another task.
To help enforce this, various pointers to sets of credentials, such as those in
the task_struct, are declared const. The purpose of this is compile-time
discouragement of altering credentials through those pointers. Once a set of
credentials has been made public through one of these pointers, it may not be
modified, except under special circumstances:
(1) Its reference count may incremented and decremented.
(2) The keyrings to which it points may be modified, but not replaced.
The only safe way to modify anything else is to create a replacement and commit
using the functions described in Documentation/credentials.txt (which will be
added by a later patch).
This patch and the preceding patches have been tested with the LTP SELinux
testsuite.
This patch makes several logical sets of alteration:
(1) execve().
This now prepares and commits credentials in various places in the
security code rather than altering the current creds directly.
(2) Temporary credential overrides.
do_coredump() and sys_faccessat() now prepare their own credentials and
temporarily override the ones currently on the acting thread, whilst
preventing interference from other threads by holding cred_replace_mutex
on the thread being dumped.
This will be replaced in a future patch by something that hands down the
credentials directly to the functions being called, rather than altering
the task's objective credentials.
(3) LSM interface.
A number of functions have been changed, added or removed:
(*) security_capset_check(), ->capset_check()
(*) security_capset_set(), ->capset_set()
Removed in favour of security_capset().
(*) security_capset(), ->capset()
New. This is passed a pointer to the new creds, a pointer to the old
creds and the proposed capability sets. It should fill in the new
creds or return an error. All pointers, barring the pointer to the
new creds, are now const.
(*) security_bprm_apply_creds(), ->bprm_apply_creds()
Changed; now returns a value, which will cause the process to be
killed if it's an error.
(*) security_task_alloc(), ->task_alloc_security()
Removed in favour of security_prepare_creds().
(*) security_cred_free(), ->cred_free()
New. Free security data attached to cred->security.
(*) security_prepare_creds(), ->cred_prepare()
New. Duplicate any security data attached to cred->security.
(*) security_commit_creds(), ->cred_commit()
New. Apply any security effects for the upcoming installation of new
security by commit_creds().
(*) security_task_post_setuid(), ->task_post_setuid()
Removed in favour of security_task_fix_setuid().
(*) security_task_fix_setuid(), ->task_fix_setuid()
Fix up the proposed new credentials for setuid(). This is used by
cap_set_fix_setuid() to implicitly adjust capabilities in line with
setuid() changes. Changes are made to the new credentials, rather
than the task itself as in security_task_post_setuid().
(*) security_task_reparent_to_init(), ->task_reparent_to_init()
Removed. Instead the task being reparented to init is referred
directly to init's credentials.
NOTE! This results in the loss of some state: SELinux's osid no
longer records the sid of the thread that forked it.
(*) security_key_alloc(), ->key_alloc()
(*) security_key_permission(), ->key_permission()
Changed. These now take cred pointers rather than task pointers to
refer to the security context.
(4) sys_capset().
This has been simplified and uses less locking. The LSM functions it
calls have been merged.
(5) reparent_to_kthreadd().
This gives the current thread the same credentials as init by simply using
commit_thread() to point that way.
(6) __sigqueue_alloc() and switch_uid()
__sigqueue_alloc() can't stop the target task from changing its creds
beneath it, so this function gets a reference to the currently applicable
user_struct which it then passes into the sigqueue struct it returns if
successful.
switch_uid() is now called from commit_creds(), and possibly should be
folded into that. commit_creds() should take care of protecting
__sigqueue_alloc().
(7) [sg]et[ug]id() and co and [sg]et_current_groups.
The set functions now all use prepare_creds(), commit_creds() and
abort_creds() to build and check a new set of credentials before applying
it.
security_task_set[ug]id() is called inside the prepared section. This
guarantees that nothing else will affect the creds until we've finished.
The calling of set_dumpable() has been moved into commit_creds().
Much of the functionality of set_user() has been moved into
commit_creds().
The get functions all simply access the data directly.
(8) security_task_prctl() and cap_task_prctl().
security_task_prctl() has been modified to return -ENOSYS if it doesn't
want to handle a function, or otherwise return the return value directly
rather than through an argument.
Additionally, cap_task_prctl() now prepares a new set of credentials, even
if it doesn't end up using it.
(9) Keyrings.
A number of changes have been made to the keyrings code:
(a) switch_uid_keyring(), copy_keys(), exit_keys() and suid_keys() have
all been dropped and built in to the credentials functions directly.
They may want separating out again later.
(b) key_alloc() and search_process_keyrings() now take a cred pointer
rather than a task pointer to specify the security context.
(c) copy_creds() gives a new thread within the same thread group a new
thread keyring if its parent had one, otherwise it discards the thread
keyring.
(d) The authorisation key now points directly to the credentials to extend
the search into rather pointing to the task that carries them.
(e) Installing thread, process or session keyrings causes a new set of
credentials to be created, even though it's not strictly necessary for
process or session keyrings (they're shared).
(10) Usermode helper.
The usermode helper code now carries a cred struct pointer in its
subprocess_info struct instead of a new session keyring pointer. This set
of credentials is derived from init_cred and installed on the new process
after it has been cloned.
call_usermodehelper_setup() allocates the new credentials and
call_usermodehelper_freeinfo() discards them if they haven't been used. A
special cred function (prepare_usermodeinfo_creds()) is provided
specifically for call_usermodehelper_setup() to call.
call_usermodehelper_setkeys() adjusts the credentials to sport the
supplied keyring as the new session keyring.
(11) SELinux.
SELinux has a number of changes, in addition to those to support the LSM
interface changes mentioned above:
(a) selinux_setprocattr() no longer does its check for whether the
current ptracer can access processes with the new SID inside the lock
that covers getting the ptracer's SID. Whilst this lock ensures that
the check is done with the ptracer pinned, the result is only valid
until the lock is released, so there's no point doing it inside the
lock.
(12) is_single_threaded().
This function has been extracted from selinux_setprocattr() and put into
a file of its own in the lib/ directory as join_session_keyring() now
wants to use it too.
The code in SELinux just checked to see whether a task shared mm_structs
with other tasks (CLONE_VM), but that isn't good enough. We really want
to know if they're part of the same thread group (CLONE_THREAD).
(13) nfsd.
The NFS server daemon now has to use the COW credentials to set the
credentials it is going to use. It really needs to pass the credentials
down to the functions it calls, but it can't do that until other patches
in this series have been applied.
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: James Morris <jmorris@namei.org>
Signed-off-by: James Morris <jmorris@namei.org>
2008-11-13 23:39:23 +00:00
|
|
|
|
2007-09-14 00:27:07 +00:00
|
|
|
fsec = file->f_security;
|
2013-01-23 22:07:38 +00:00
|
|
|
isec = file_inode(file)->i_security;
|
2007-09-14 00:27:07 +00:00
|
|
|
/*
|
|
|
|
* Save inode label and policy sequence number
|
|
|
|
* at open-time so that selinux_file_permission
|
|
|
|
* can determine whether revalidation is necessary.
|
|
|
|
* Task label is already saved in the file security
|
|
|
|
* struct as its SID.
|
|
|
|
*/
|
|
|
|
fsec->isid = isec->sid;
|
|
|
|
fsec->pseqno = avc_policy_seqno();
|
|
|
|
/*
|
|
|
|
* Since the inode label or policy seqno may have changed
|
|
|
|
* between the selinux_inode_permission check and the saving
|
|
|
|
* of state above, recheck that access is still permitted.
|
|
|
|
* Otherwise, access might never be revalidated against the
|
|
|
|
* new inode label or new policy.
|
|
|
|
* This check is not redundant - do not remove.
|
|
|
|
*/
|
2013-06-13 22:37:55 +00:00
|
|
|
return file_path_has_perm(cred, file, open_file_to_av(file));
|
2007-09-14 00:27:07 +00:00
|
|
|
}
|
|
|
|
|
2005-04-16 22:20:36 +00:00
|
|
|
/* task security operations */
|
|
|
|
|
|
|
|
static int selinux_task_create(unsigned long clone_flags)
|
|
|
|
{
|
2008-11-13 23:39:26 +00:00
|
|
|
return current_has_perm(current, PROCESS__FORK);
|
2005-04-16 22:20:36 +00:00
|
|
|
}
|
|
|
|
|
KEYS: Add a keyctl to install a process's session keyring on its parent [try #6]
Add a keyctl to install a process's session keyring onto its parent. This
replaces the parent's session keyring. Because the COW credential code does
not permit one process to change another process's credentials directly, the
change is deferred until userspace next starts executing again. Normally this
will be after a wait*() syscall.
To support this, three new security hooks have been provided:
cred_alloc_blank() to allocate unset security creds, cred_transfer() to fill in
the blank security creds and key_session_to_parent() - which asks the LSM if
the process may replace its parent's session keyring.
The replacement may only happen if the process has the same ownership details
as its parent, and the process has LINK permission on the session keyring, and
the session keyring is owned by the process, and the LSM permits it.
Note that this requires alteration to each architecture's notify_resume path.
This has been done for all arches barring blackfin, m68k* and xtensa, all of
which need assembly alteration to support TIF_NOTIFY_RESUME. This allows the
replacement to be performed at the point the parent process resumes userspace
execution.
This allows the userspace AFS pioctl emulation to fully emulate newpag() and
the VIOCSETTOK and VIOCSETTOK2 pioctls, all of which require the ability to
alter the parent process's PAG membership. However, since kAFS doesn't use
PAGs per se, but rather dumps the keys into the session keyring, the session
keyring of the parent must be replaced if, for example, VIOCSETTOK is passed
the newpag flag.
This can be tested with the following program:
#include <stdio.h>
#include <stdlib.h>
#include <keyutils.h>
#define KEYCTL_SESSION_TO_PARENT 18
#define OSERROR(X, S) do { if ((long)(X) == -1) { perror(S); exit(1); } } while(0)
int main(int argc, char **argv)
{
key_serial_t keyring, key;
long ret;
keyring = keyctl_join_session_keyring(argv[1]);
OSERROR(keyring, "keyctl_join_session_keyring");
key = add_key("user", "a", "b", 1, keyring);
OSERROR(key, "add_key");
ret = keyctl(KEYCTL_SESSION_TO_PARENT);
OSERROR(ret, "KEYCTL_SESSION_TO_PARENT");
return 0;
}
Compiled and linked with -lkeyutils, you should see something like:
[dhowells@andromeda ~]$ keyctl show
Session Keyring
-3 --alswrv 4043 4043 keyring: _ses
355907932 --alswrv 4043 -1 \_ keyring: _uid.4043
[dhowells@andromeda ~]$ /tmp/newpag
[dhowells@andromeda ~]$ keyctl show
Session Keyring
-3 --alswrv 4043 4043 keyring: _ses
1055658746 --alswrv 4043 4043 \_ user: a
[dhowells@andromeda ~]$ /tmp/newpag hello
[dhowells@andromeda ~]$ keyctl show
Session Keyring
-3 --alswrv 4043 4043 keyring: hello
340417692 --alswrv 4043 4043 \_ user: a
Where the test program creates a new session keyring, sticks a user key named
'a' into it and then installs it on its parent.
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: James Morris <jmorris@namei.org>
2009-09-02 08:14:21 +00:00
|
|
|
/*
|
|
|
|
* allocate the SELinux part of blank credentials
|
|
|
|
*/
|
|
|
|
static int selinux_cred_alloc_blank(struct cred *cred, gfp_t gfp)
|
|
|
|
{
|
|
|
|
struct task_security_struct *tsec;
|
|
|
|
|
|
|
|
tsec = kzalloc(sizeof(struct task_security_struct), gfp);
|
|
|
|
if (!tsec)
|
|
|
|
return -ENOMEM;
|
|
|
|
|
|
|
|
cred->security = tsec;
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
CRED: Inaugurate COW credentials
Inaugurate copy-on-write credentials management. This uses RCU to manage the
credentials pointer in the task_struct with respect to accesses by other tasks.
A process may only modify its own credentials, and so does not need locking to
access or modify its own credentials.
A mutex (cred_replace_mutex) is added to the task_struct to control the effect
of PTRACE_ATTACHED on credential calculations, particularly with respect to
execve().
With this patch, the contents of an active credentials struct may not be
changed directly; rather a new set of credentials must be prepared, modified
and committed using something like the following sequence of events:
struct cred *new = prepare_creds();
int ret = blah(new);
if (ret < 0) {
abort_creds(new);
return ret;
}
return commit_creds(new);
There are some exceptions to this rule: the keyrings pointed to by the active
credentials may be instantiated - keyrings violate the COW rule as managing
COW keyrings is tricky, given that it is possible for a task to directly alter
the keys in a keyring in use by another task.
To help enforce this, various pointers to sets of credentials, such as those in
the task_struct, are declared const. The purpose of this is compile-time
discouragement of altering credentials through those pointers. Once a set of
credentials has been made public through one of these pointers, it may not be
modified, except under special circumstances:
(1) Its reference count may incremented and decremented.
(2) The keyrings to which it points may be modified, but not replaced.
The only safe way to modify anything else is to create a replacement and commit
using the functions described in Documentation/credentials.txt (which will be
added by a later patch).
This patch and the preceding patches have been tested with the LTP SELinux
testsuite.
This patch makes several logical sets of alteration:
(1) execve().
This now prepares and commits credentials in various places in the
security code rather than altering the current creds directly.
(2) Temporary credential overrides.
do_coredump() and sys_faccessat() now prepare their own credentials and
temporarily override the ones currently on the acting thread, whilst
preventing interference from other threads by holding cred_replace_mutex
on the thread being dumped.
This will be replaced in a future patch by something that hands down the
credentials directly to the functions being called, rather than altering
the task's objective credentials.
(3) LSM interface.
A number of functions have been changed, added or removed:
(*) security_capset_check(), ->capset_check()
(*) security_capset_set(), ->capset_set()
Removed in favour of security_capset().
(*) security_capset(), ->capset()
New. This is passed a pointer to the new creds, a pointer to the old
creds and the proposed capability sets. It should fill in the new
creds or return an error. All pointers, barring the pointer to the
new creds, are now const.
(*) security_bprm_apply_creds(), ->bprm_apply_creds()
Changed; now returns a value, which will cause the process to be
killed if it's an error.
(*) security_task_alloc(), ->task_alloc_security()
Removed in favour of security_prepare_creds().
(*) security_cred_free(), ->cred_free()
New. Free security data attached to cred->security.
(*) security_prepare_creds(), ->cred_prepare()
New. Duplicate any security data attached to cred->security.
(*) security_commit_creds(), ->cred_commit()
New. Apply any security effects for the upcoming installation of new
security by commit_creds().
(*) security_task_post_setuid(), ->task_post_setuid()
Removed in favour of security_task_fix_setuid().
(*) security_task_fix_setuid(), ->task_fix_setuid()
Fix up the proposed new credentials for setuid(). This is used by
cap_set_fix_setuid() to implicitly adjust capabilities in line with
setuid() changes. Changes are made to the new credentials, rather
than the task itself as in security_task_post_setuid().
(*) security_task_reparent_to_init(), ->task_reparent_to_init()
Removed. Instead the task being reparented to init is referred
directly to init's credentials.
NOTE! This results in the loss of some state: SELinux's osid no
longer records the sid of the thread that forked it.
(*) security_key_alloc(), ->key_alloc()
(*) security_key_permission(), ->key_permission()
Changed. These now take cred pointers rather than task pointers to
refer to the security context.
(4) sys_capset().
This has been simplified and uses less locking. The LSM functions it
calls have been merged.
(5) reparent_to_kthreadd().
This gives the current thread the same credentials as init by simply using
commit_thread() to point that way.
(6) __sigqueue_alloc() and switch_uid()
__sigqueue_alloc() can't stop the target task from changing its creds
beneath it, so this function gets a reference to the currently applicable
user_struct which it then passes into the sigqueue struct it returns if
successful.
switch_uid() is now called from commit_creds(), and possibly should be
folded into that. commit_creds() should take care of protecting
__sigqueue_alloc().
(7) [sg]et[ug]id() and co and [sg]et_current_groups.
The set functions now all use prepare_creds(), commit_creds() and
abort_creds() to build and check a new set of credentials before applying
it.
security_task_set[ug]id() is called inside the prepared section. This
guarantees that nothing else will affect the creds until we've finished.
The calling of set_dumpable() has been moved into commit_creds().
Much of the functionality of set_user() has been moved into
commit_creds().
The get functions all simply access the data directly.
(8) security_task_prctl() and cap_task_prctl().
security_task_prctl() has been modified to return -ENOSYS if it doesn't
want to handle a function, or otherwise return the return value directly
rather than through an argument.
Additionally, cap_task_prctl() now prepares a new set of credentials, even
if it doesn't end up using it.
(9) Keyrings.
A number of changes have been made to the keyrings code:
(a) switch_uid_keyring(), copy_keys(), exit_keys() and suid_keys() have
all been dropped and built in to the credentials functions directly.
They may want separating out again later.
(b) key_alloc() and search_process_keyrings() now take a cred pointer
rather than a task pointer to specify the security context.
(c) copy_creds() gives a new thread within the same thread group a new
thread keyring if its parent had one, otherwise it discards the thread
keyring.
(d) The authorisation key now points directly to the credentials to extend
the search into rather pointing to the task that carries them.
(e) Installing thread, process or session keyrings causes a new set of
credentials to be created, even though it's not strictly necessary for
process or session keyrings (they're shared).
(10) Usermode helper.
The usermode helper code now carries a cred struct pointer in its
subprocess_info struct instead of a new session keyring pointer. This set
of credentials is derived from init_cred and installed on the new process
after it has been cloned.
call_usermodehelper_setup() allocates the new credentials and
call_usermodehelper_freeinfo() discards them if they haven't been used. A
special cred function (prepare_usermodeinfo_creds()) is provided
specifically for call_usermodehelper_setup() to call.
call_usermodehelper_setkeys() adjusts the credentials to sport the
supplied keyring as the new session keyring.
(11) SELinux.
SELinux has a number of changes, in addition to those to support the LSM
interface changes mentioned above:
(a) selinux_setprocattr() no longer does its check for whether the
current ptracer can access processes with the new SID inside the lock
that covers getting the ptracer's SID. Whilst this lock ensures that
the check is done with the ptracer pinned, the result is only valid
until the lock is released, so there's no point doing it inside the
lock.
(12) is_single_threaded().
This function has been extracted from selinux_setprocattr() and put into
a file of its own in the lib/ directory as join_session_keyring() now
wants to use it too.
The code in SELinux just checked to see whether a task shared mm_structs
with other tasks (CLONE_VM), but that isn't good enough. We really want
to know if they're part of the same thread group (CLONE_THREAD).
(13) nfsd.
The NFS server daemon now has to use the COW credentials to set the
credentials it is going to use. It really needs to pass the credentials
down to the functions it calls, but it can't do that until other patches
in this series have been applied.
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: James Morris <jmorris@namei.org>
Signed-off-by: James Morris <jmorris@namei.org>
2008-11-13 23:39:23 +00:00
|
|
|
/*
|
|
|
|
* detach and free the LSM part of a set of credentials
|
|
|
|
*/
|
|
|
|
static void selinux_cred_free(struct cred *cred)
|
2005-04-16 22:20:36 +00:00
|
|
|
{
|
CRED: Inaugurate COW credentials
Inaugurate copy-on-write credentials management. This uses RCU to manage the
credentials pointer in the task_struct with respect to accesses by other tasks.
A process may only modify its own credentials, and so does not need locking to
access or modify its own credentials.
A mutex (cred_replace_mutex) is added to the task_struct to control the effect
of PTRACE_ATTACHED on credential calculations, particularly with respect to
execve().
With this patch, the contents of an active credentials struct may not be
changed directly; rather a new set of credentials must be prepared, modified
and committed using something like the following sequence of events:
struct cred *new = prepare_creds();
int ret = blah(new);
if (ret < 0) {
abort_creds(new);
return ret;
}
return commit_creds(new);
There are some exceptions to this rule: the keyrings pointed to by the active
credentials may be instantiated - keyrings violate the COW rule as managing
COW keyrings is tricky, given that it is possible for a task to directly alter
the keys in a keyring in use by another task.
To help enforce this, various pointers to sets of credentials, such as those in
the task_struct, are declared const. The purpose of this is compile-time
discouragement of altering credentials through those pointers. Once a set of
credentials has been made public through one of these pointers, it may not be
modified, except under special circumstances:
(1) Its reference count may incremented and decremented.
(2) The keyrings to which it points may be modified, but not replaced.
The only safe way to modify anything else is to create a replacement and commit
using the functions described in Documentation/credentials.txt (which will be
added by a later patch).
This patch and the preceding patches have been tested with the LTP SELinux
testsuite.
This patch makes several logical sets of alteration:
(1) execve().
This now prepares and commits credentials in various places in the
security code rather than altering the current creds directly.
(2) Temporary credential overrides.
do_coredump() and sys_faccessat() now prepare their own credentials and
temporarily override the ones currently on the acting thread, whilst
preventing interference from other threads by holding cred_replace_mutex
on the thread being dumped.
This will be replaced in a future patch by something that hands down the
credentials directly to the functions being called, rather than altering
the task's objective credentials.
(3) LSM interface.
A number of functions have been changed, added or removed:
(*) security_capset_check(), ->capset_check()
(*) security_capset_set(), ->capset_set()
Removed in favour of security_capset().
(*) security_capset(), ->capset()
New. This is passed a pointer to the new creds, a pointer to the old
creds and the proposed capability sets. It should fill in the new
creds or return an error. All pointers, barring the pointer to the
new creds, are now const.
(*) security_bprm_apply_creds(), ->bprm_apply_creds()
Changed; now returns a value, which will cause the process to be
killed if it's an error.
(*) security_task_alloc(), ->task_alloc_security()
Removed in favour of security_prepare_creds().
(*) security_cred_free(), ->cred_free()
New. Free security data attached to cred->security.
(*) security_prepare_creds(), ->cred_prepare()
New. Duplicate any security data attached to cred->security.
(*) security_commit_creds(), ->cred_commit()
New. Apply any security effects for the upcoming installation of new
security by commit_creds().
(*) security_task_post_setuid(), ->task_post_setuid()
Removed in favour of security_task_fix_setuid().
(*) security_task_fix_setuid(), ->task_fix_setuid()
Fix up the proposed new credentials for setuid(). This is used by
cap_set_fix_setuid() to implicitly adjust capabilities in line with
setuid() changes. Changes are made to the new credentials, rather
than the task itself as in security_task_post_setuid().
(*) security_task_reparent_to_init(), ->task_reparent_to_init()
Removed. Instead the task being reparented to init is referred
directly to init's credentials.
NOTE! This results in the loss of some state: SELinux's osid no
longer records the sid of the thread that forked it.
(*) security_key_alloc(), ->key_alloc()
(*) security_key_permission(), ->key_permission()
Changed. These now take cred pointers rather than task pointers to
refer to the security context.
(4) sys_capset().
This has been simplified and uses less locking. The LSM functions it
calls have been merged.
(5) reparent_to_kthreadd().
This gives the current thread the same credentials as init by simply using
commit_thread() to point that way.
(6) __sigqueue_alloc() and switch_uid()
__sigqueue_alloc() can't stop the target task from changing its creds
beneath it, so this function gets a reference to the currently applicable
user_struct which it then passes into the sigqueue struct it returns if
successful.
switch_uid() is now called from commit_creds(), and possibly should be
folded into that. commit_creds() should take care of protecting
__sigqueue_alloc().
(7) [sg]et[ug]id() and co and [sg]et_current_groups.
The set functions now all use prepare_creds(), commit_creds() and
abort_creds() to build and check a new set of credentials before applying
it.
security_task_set[ug]id() is called inside the prepared section. This
guarantees that nothing else will affect the creds until we've finished.
The calling of set_dumpable() has been moved into commit_creds().
Much of the functionality of set_user() has been moved into
commit_creds().
The get functions all simply access the data directly.
(8) security_task_prctl() and cap_task_prctl().
security_task_prctl() has been modified to return -ENOSYS if it doesn't
want to handle a function, or otherwise return the return value directly
rather than through an argument.
Additionally, cap_task_prctl() now prepares a new set of credentials, even
if it doesn't end up using it.
(9) Keyrings.
A number of changes have been made to the keyrings code:
(a) switch_uid_keyring(), copy_keys(), exit_keys() and suid_keys() have
all been dropped and built in to the credentials functions directly.
They may want separating out again later.
(b) key_alloc() and search_process_keyrings() now take a cred pointer
rather than a task pointer to specify the security context.
(c) copy_creds() gives a new thread within the same thread group a new
thread keyring if its parent had one, otherwise it discards the thread
keyring.
(d) The authorisation key now points directly to the credentials to extend
the search into rather pointing to the task that carries them.
(e) Installing thread, process or session keyrings causes a new set of
credentials to be created, even though it's not strictly necessary for
process or session keyrings (they're shared).
(10) Usermode helper.
The usermode helper code now carries a cred struct pointer in its
subprocess_info struct instead of a new session keyring pointer. This set
of credentials is derived from init_cred and installed on the new process
after it has been cloned.
call_usermodehelper_setup() allocates the new credentials and
call_usermodehelper_freeinfo() discards them if they haven't been used. A
special cred function (prepare_usermodeinfo_creds()) is provided
specifically for call_usermodehelper_setup() to call.
call_usermodehelper_setkeys() adjusts the credentials to sport the
supplied keyring as the new session keyring.
(11) SELinux.
SELinux has a number of changes, in addition to those to support the LSM
interface changes mentioned above:
(a) selinux_setprocattr() no longer does its check for whether the
current ptracer can access processes with the new SID inside the lock
that covers getting the ptracer's SID. Whilst this lock ensures that
the check is done with the ptracer pinned, the result is only valid
until the lock is released, so there's no point doing it inside the
lock.
(12) is_single_threaded().
This function has been extracted from selinux_setprocattr() and put into
a file of its own in the lib/ directory as join_session_keyring() now
wants to use it too.
The code in SELinux just checked to see whether a task shared mm_structs
with other tasks (CLONE_VM), but that isn't good enough. We really want
to know if they're part of the same thread group (CLONE_THREAD).
(13) nfsd.
The NFS server daemon now has to use the COW credentials to set the
credentials it is going to use. It really needs to pass the credentials
down to the functions it calls, but it can't do that until other patches
in this series have been applied.
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: James Morris <jmorris@namei.org>
Signed-off-by: James Morris <jmorris@namei.org>
2008-11-13 23:39:23 +00:00
|
|
|
struct task_security_struct *tsec = cred->security;
|
2009-09-02 08:13:40 +00:00
|
|
|
|
2011-02-07 13:36:10 +00:00
|
|
|
/*
|
|
|
|
* cred->security == NULL if security_cred_alloc_blank() or
|
|
|
|
* security_prepare_creds() returned an error.
|
|
|
|
*/
|
|
|
|
BUG_ON(cred->security && (unsigned long) cred->security < PAGE_SIZE);
|
2009-09-02 08:13:40 +00:00
|
|
|
cred->security = (void *) 0x7UL;
|
CRED: Inaugurate COW credentials
Inaugurate copy-on-write credentials management. This uses RCU to manage the
credentials pointer in the task_struct with respect to accesses by other tasks.
A process may only modify its own credentials, and so does not need locking to
access or modify its own credentials.
A mutex (cred_replace_mutex) is added to the task_struct to control the effect
of PTRACE_ATTACHED on credential calculations, particularly with respect to
execve().
With this patch, the contents of an active credentials struct may not be
changed directly; rather a new set of credentials must be prepared, modified
and committed using something like the following sequence of events:
struct cred *new = prepare_creds();
int ret = blah(new);
if (ret < 0) {
abort_creds(new);
return ret;
}
return commit_creds(new);
There are some exceptions to this rule: the keyrings pointed to by the active
credentials may be instantiated - keyrings violate the COW rule as managing
COW keyrings is tricky, given that it is possible for a task to directly alter
the keys in a keyring in use by another task.
To help enforce this, various pointers to sets of credentials, such as those in
the task_struct, are declared const. The purpose of this is compile-time
discouragement of altering credentials through those pointers. Once a set of
credentials has been made public through one of these pointers, it may not be
modified, except under special circumstances:
(1) Its reference count may incremented and decremented.
(2) The keyrings to which it points may be modified, but not replaced.
The only safe way to modify anything else is to create a replacement and commit
using the functions described in Documentation/credentials.txt (which will be
added by a later patch).
This patch and the preceding patches have been tested with the LTP SELinux
testsuite.
This patch makes several logical sets of alteration:
(1) execve().
This now prepares and commits credentials in various places in the
security code rather than altering the current creds directly.
(2) Temporary credential overrides.
do_coredump() and sys_faccessat() now prepare their own credentials and
temporarily override the ones currently on the acting thread, whilst
preventing interference from other threads by holding cred_replace_mutex
on the thread being dumped.
This will be replaced in a future patch by something that hands down the
credentials directly to the functions being called, rather than altering
the task's objective credentials.
(3) LSM interface.
A number of functions have been changed, added or removed:
(*) security_capset_check(), ->capset_check()
(*) security_capset_set(), ->capset_set()
Removed in favour of security_capset().
(*) security_capset(), ->capset()
New. This is passed a pointer to the new creds, a pointer to the old
creds and the proposed capability sets. It should fill in the new
creds or return an error. All pointers, barring the pointer to the
new creds, are now const.
(*) security_bprm_apply_creds(), ->bprm_apply_creds()
Changed; now returns a value, which will cause the process to be
killed if it's an error.
(*) security_task_alloc(), ->task_alloc_security()
Removed in favour of security_prepare_creds().
(*) security_cred_free(), ->cred_free()
New. Free security data attached to cred->security.
(*) security_prepare_creds(), ->cred_prepare()
New. Duplicate any security data attached to cred->security.
(*) security_commit_creds(), ->cred_commit()
New. Apply any security effects for the upcoming installation of new
security by commit_creds().
(*) security_task_post_setuid(), ->task_post_setuid()
Removed in favour of security_task_fix_setuid().
(*) security_task_fix_setuid(), ->task_fix_setuid()
Fix up the proposed new credentials for setuid(). This is used by
cap_set_fix_setuid() to implicitly adjust capabilities in line with
setuid() changes. Changes are made to the new credentials, rather
than the task itself as in security_task_post_setuid().
(*) security_task_reparent_to_init(), ->task_reparent_to_init()
Removed. Instead the task being reparented to init is referred
directly to init's credentials.
NOTE! This results in the loss of some state: SELinux's osid no
longer records the sid of the thread that forked it.
(*) security_key_alloc(), ->key_alloc()
(*) security_key_permission(), ->key_permission()
Changed. These now take cred pointers rather than task pointers to
refer to the security context.
(4) sys_capset().
This has been simplified and uses less locking. The LSM functions it
calls have been merged.
(5) reparent_to_kthreadd().
This gives the current thread the same credentials as init by simply using
commit_thread() to point that way.
(6) __sigqueue_alloc() and switch_uid()
__sigqueue_alloc() can't stop the target task from changing its creds
beneath it, so this function gets a reference to the currently applicable
user_struct which it then passes into the sigqueue struct it returns if
successful.
switch_uid() is now called from commit_creds(), and possibly should be
folded into that. commit_creds() should take care of protecting
__sigqueue_alloc().
(7) [sg]et[ug]id() and co and [sg]et_current_groups.
The set functions now all use prepare_creds(), commit_creds() and
abort_creds() to build and check a new set of credentials before applying
it.
security_task_set[ug]id() is called inside the prepared section. This
guarantees that nothing else will affect the creds until we've finished.
The calling of set_dumpable() has been moved into commit_creds().
Much of the functionality of set_user() has been moved into
commit_creds().
The get functions all simply access the data directly.
(8) security_task_prctl() and cap_task_prctl().
security_task_prctl() has been modified to return -ENOSYS if it doesn't
want to handle a function, or otherwise return the return value directly
rather than through an argument.
Additionally, cap_task_prctl() now prepares a new set of credentials, even
if it doesn't end up using it.
(9) Keyrings.
A number of changes have been made to the keyrings code:
(a) switch_uid_keyring(), copy_keys(), exit_keys() and suid_keys() have
all been dropped and built in to the credentials functions directly.
They may want separating out again later.
(b) key_alloc() and search_process_keyrings() now take a cred pointer
rather than a task pointer to specify the security context.
(c) copy_creds() gives a new thread within the same thread group a new
thread keyring if its parent had one, otherwise it discards the thread
keyring.
(d) The authorisation key now points directly to the credentials to extend
the search into rather pointing to the task that carries them.
(e) Installing thread, process or session keyrings causes a new set of
credentials to be created, even though it's not strictly necessary for
process or session keyrings (they're shared).
(10) Usermode helper.
The usermode helper code now carries a cred struct pointer in its
subprocess_info struct instead of a new session keyring pointer. This set
of credentials is derived from init_cred and installed on the new process
after it has been cloned.
call_usermodehelper_setup() allocates the new credentials and
call_usermodehelper_freeinfo() discards them if they haven't been used. A
special cred function (prepare_usermodeinfo_creds()) is provided
specifically for call_usermodehelper_setup() to call.
call_usermodehelper_setkeys() adjusts the credentials to sport the
supplied keyring as the new session keyring.
(11) SELinux.
SELinux has a number of changes, in addition to those to support the LSM
interface changes mentioned above:
(a) selinux_setprocattr() no longer does its check for whether the
current ptracer can access processes with the new SID inside the lock
that covers getting the ptracer's SID. Whilst this lock ensures that
the check is done with the ptracer pinned, the result is only valid
until the lock is released, so there's no point doing it inside the
lock.
(12) is_single_threaded().
This function has been extracted from selinux_setprocattr() and put into
a file of its own in the lib/ directory as join_session_keyring() now
wants to use it too.
The code in SELinux just checked to see whether a task shared mm_structs
with other tasks (CLONE_VM), but that isn't good enough. We really want
to know if they're part of the same thread group (CLONE_THREAD).
(13) nfsd.
The NFS server daemon now has to use the COW credentials to set the
credentials it is going to use. It really needs to pass the credentials
down to the functions it calls, but it can't do that until other patches
in this series have been applied.
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: James Morris <jmorris@namei.org>
Signed-off-by: James Morris <jmorris@namei.org>
2008-11-13 23:39:23 +00:00
|
|
|
kfree(tsec);
|
|
|
|
}
|
2005-04-16 22:20:36 +00:00
|
|
|
|
CRED: Inaugurate COW credentials
Inaugurate copy-on-write credentials management. This uses RCU to manage the
credentials pointer in the task_struct with respect to accesses by other tasks.
A process may only modify its own credentials, and so does not need locking to
access or modify its own credentials.
A mutex (cred_replace_mutex) is added to the task_struct to control the effect
of PTRACE_ATTACHED on credential calculations, particularly with respect to
execve().
With this patch, the contents of an active credentials struct may not be
changed directly; rather a new set of credentials must be prepared, modified
and committed using something like the following sequence of events:
struct cred *new = prepare_creds();
int ret = blah(new);
if (ret < 0) {
abort_creds(new);
return ret;
}
return commit_creds(new);
There are some exceptions to this rule: the keyrings pointed to by the active
credentials may be instantiated - keyrings violate the COW rule as managing
COW keyrings is tricky, given that it is possible for a task to directly alter
the keys in a keyring in use by another task.
To help enforce this, various pointers to sets of credentials, such as those in
the task_struct, are declared const. The purpose of this is compile-time
discouragement of altering credentials through those pointers. Once a set of
credentials has been made public through one of these pointers, it may not be
modified, except under special circumstances:
(1) Its reference count may incremented and decremented.
(2) The keyrings to which it points may be modified, but not replaced.
The only safe way to modify anything else is to create a replacement and commit
using the functions described in Documentation/credentials.txt (which will be
added by a later patch).
This patch and the preceding patches have been tested with the LTP SELinux
testsuite.
This patch makes several logical sets of alteration:
(1) execve().
This now prepares and commits credentials in various places in the
security code rather than altering the current creds directly.
(2) Temporary credential overrides.
do_coredump() and sys_faccessat() now prepare their own credentials and
temporarily override the ones currently on the acting thread, whilst
preventing interference from other threads by holding cred_replace_mutex
on the thread being dumped.
This will be replaced in a future patch by something that hands down the
credentials directly to the functions being called, rather than altering
the task's objective credentials.
(3) LSM interface.
A number of functions have been changed, added or removed:
(*) security_capset_check(), ->capset_check()
(*) security_capset_set(), ->capset_set()
Removed in favour of security_capset().
(*) security_capset(), ->capset()
New. This is passed a pointer to the new creds, a pointer to the old
creds and the proposed capability sets. It should fill in the new
creds or return an error. All pointers, barring the pointer to the
new creds, are now const.
(*) security_bprm_apply_creds(), ->bprm_apply_creds()
Changed; now returns a value, which will cause the process to be
killed if it's an error.
(*) security_task_alloc(), ->task_alloc_security()
Removed in favour of security_prepare_creds().
(*) security_cred_free(), ->cred_free()
New. Free security data attached to cred->security.
(*) security_prepare_creds(), ->cred_prepare()
New. Duplicate any security data attached to cred->security.
(*) security_commit_creds(), ->cred_commit()
New. Apply any security effects for the upcoming installation of new
security by commit_creds().
(*) security_task_post_setuid(), ->task_post_setuid()
Removed in favour of security_task_fix_setuid().
(*) security_task_fix_setuid(), ->task_fix_setuid()
Fix up the proposed new credentials for setuid(). This is used by
cap_set_fix_setuid() to implicitly adjust capabilities in line with
setuid() changes. Changes are made to the new credentials, rather
than the task itself as in security_task_post_setuid().
(*) security_task_reparent_to_init(), ->task_reparent_to_init()
Removed. Instead the task being reparented to init is referred
directly to init's credentials.
NOTE! This results in the loss of some state: SELinux's osid no
longer records the sid of the thread that forked it.
(*) security_key_alloc(), ->key_alloc()
(*) security_key_permission(), ->key_permission()
Changed. These now take cred pointers rather than task pointers to
refer to the security context.
(4) sys_capset().
This has been simplified and uses less locking. The LSM functions it
calls have been merged.
(5) reparent_to_kthreadd().
This gives the current thread the same credentials as init by simply using
commit_thread() to point that way.
(6) __sigqueue_alloc() and switch_uid()
__sigqueue_alloc() can't stop the target task from changing its creds
beneath it, so this function gets a reference to the currently applicable
user_struct which it then passes into the sigqueue struct it returns if
successful.
switch_uid() is now called from commit_creds(), and possibly should be
folded into that. commit_creds() should take care of protecting
__sigqueue_alloc().
(7) [sg]et[ug]id() and co and [sg]et_current_groups.
The set functions now all use prepare_creds(), commit_creds() and
abort_creds() to build and check a new set of credentials before applying
it.
security_task_set[ug]id() is called inside the prepared section. This
guarantees that nothing else will affect the creds until we've finished.
The calling of set_dumpable() has been moved into commit_creds().
Much of the functionality of set_user() has been moved into
commit_creds().
The get functions all simply access the data directly.
(8) security_task_prctl() and cap_task_prctl().
security_task_prctl() has been modified to return -ENOSYS if it doesn't
want to handle a function, or otherwise return the return value directly
rather than through an argument.
Additionally, cap_task_prctl() now prepares a new set of credentials, even
if it doesn't end up using it.
(9) Keyrings.
A number of changes have been made to the keyrings code:
(a) switch_uid_keyring(), copy_keys(), exit_keys() and suid_keys() have
all been dropped and built in to the credentials functions directly.
They may want separating out again later.
(b) key_alloc() and search_process_keyrings() now take a cred pointer
rather than a task pointer to specify the security context.
(c) copy_creds() gives a new thread within the same thread group a new
thread keyring if its parent had one, otherwise it discards the thread
keyring.
(d) The authorisation key now points directly to the credentials to extend
the search into rather pointing to the task that carries them.
(e) Installing thread, process or session keyrings causes a new set of
credentials to be created, even though it's not strictly necessary for
process or session keyrings (they're shared).
(10) Usermode helper.
The usermode helper code now carries a cred struct pointer in its
subprocess_info struct instead of a new session keyring pointer. This set
of credentials is derived from init_cred and installed on the new process
after it has been cloned.
call_usermodehelper_setup() allocates the new credentials and
call_usermodehelper_freeinfo() discards them if they haven't been used. A
special cred function (prepare_usermodeinfo_creds()) is provided
specifically for call_usermodehelper_setup() to call.
call_usermodehelper_setkeys() adjusts the credentials to sport the
supplied keyring as the new session keyring.
(11) SELinux.
SELinux has a number of changes, in addition to those to support the LSM
interface changes mentioned above:
(a) selinux_setprocattr() no longer does its check for whether the
current ptracer can access processes with the new SID inside the lock
that covers getting the ptracer's SID. Whilst this lock ensures that
the check is done with the ptracer pinned, the result is only valid
until the lock is released, so there's no point doing it inside the
lock.
(12) is_single_threaded().
This function has been extracted from selinux_setprocattr() and put into
a file of its own in the lib/ directory as join_session_keyring() now
wants to use it too.
The code in SELinux just checked to see whether a task shared mm_structs
with other tasks (CLONE_VM), but that isn't good enough. We really want
to know if they're part of the same thread group (CLONE_THREAD).
(13) nfsd.
The NFS server daemon now has to use the COW credentials to set the
credentials it is going to use. It really needs to pass the credentials
down to the functions it calls, but it can't do that until other patches
in this series have been applied.
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: James Morris <jmorris@namei.org>
Signed-off-by: James Morris <jmorris@namei.org>
2008-11-13 23:39:23 +00:00
|
|
|
/*
|
|
|
|
* prepare a new set of credentials for modification
|
|
|
|
*/
|
|
|
|
static int selinux_cred_prepare(struct cred *new, const struct cred *old,
|
|
|
|
gfp_t gfp)
|
|
|
|
{
|
|
|
|
const struct task_security_struct *old_tsec;
|
|
|
|
struct task_security_struct *tsec;
|
2005-04-16 22:20:36 +00:00
|
|
|
|
CRED: Inaugurate COW credentials
Inaugurate copy-on-write credentials management. This uses RCU to manage the
credentials pointer in the task_struct with respect to accesses by other tasks.
A process may only modify its own credentials, and so does not need locking to
access or modify its own credentials.
A mutex (cred_replace_mutex) is added to the task_struct to control the effect
of PTRACE_ATTACHED on credential calculations, particularly with respect to
execve().
With this patch, the contents of an active credentials struct may not be
changed directly; rather a new set of credentials must be prepared, modified
and committed using something like the following sequence of events:
struct cred *new = prepare_creds();
int ret = blah(new);
if (ret < 0) {
abort_creds(new);
return ret;
}
return commit_creds(new);
There are some exceptions to this rule: the keyrings pointed to by the active
credentials may be instantiated - keyrings violate the COW rule as managing
COW keyrings is tricky, given that it is possible for a task to directly alter
the keys in a keyring in use by another task.
To help enforce this, various pointers to sets of credentials, such as those in
the task_struct, are declared const. The purpose of this is compile-time
discouragement of altering credentials through those pointers. Once a set of
credentials has been made public through one of these pointers, it may not be
modified, except under special circumstances:
(1) Its reference count may incremented and decremented.
(2) The keyrings to which it points may be modified, but not replaced.
The only safe way to modify anything else is to create a replacement and commit
using the functions described in Documentation/credentials.txt (which will be
added by a later patch).
This patch and the preceding patches have been tested with the LTP SELinux
testsuite.
This patch makes several logical sets of alteration:
(1) execve().
This now prepares and commits credentials in various places in the
security code rather than altering the current creds directly.
(2) Temporary credential overrides.
do_coredump() and sys_faccessat() now prepare their own credentials and
temporarily override the ones currently on the acting thread, whilst
preventing interference from other threads by holding cred_replace_mutex
on the thread being dumped.
This will be replaced in a future patch by something that hands down the
credentials directly to the functions being called, rather than altering
the task's objective credentials.
(3) LSM interface.
A number of functions have been changed, added or removed:
(*) security_capset_check(), ->capset_check()
(*) security_capset_set(), ->capset_set()
Removed in favour of security_capset().
(*) security_capset(), ->capset()
New. This is passed a pointer to the new creds, a pointer to the old
creds and the proposed capability sets. It should fill in the new
creds or return an error. All pointers, barring the pointer to the
new creds, are now const.
(*) security_bprm_apply_creds(), ->bprm_apply_creds()
Changed; now returns a value, which will cause the process to be
killed if it's an error.
(*) security_task_alloc(), ->task_alloc_security()
Removed in favour of security_prepare_creds().
(*) security_cred_free(), ->cred_free()
New. Free security data attached to cred->security.
(*) security_prepare_creds(), ->cred_prepare()
New. Duplicate any security data attached to cred->security.
(*) security_commit_creds(), ->cred_commit()
New. Apply any security effects for the upcoming installation of new
security by commit_creds().
(*) security_task_post_setuid(), ->task_post_setuid()
Removed in favour of security_task_fix_setuid().
(*) security_task_fix_setuid(), ->task_fix_setuid()
Fix up the proposed new credentials for setuid(). This is used by
cap_set_fix_setuid() to implicitly adjust capabilities in line with
setuid() changes. Changes are made to the new credentials, rather
than the task itself as in security_task_post_setuid().
(*) security_task_reparent_to_init(), ->task_reparent_to_init()
Removed. Instead the task being reparented to init is referred
directly to init's credentials.
NOTE! This results in the loss of some state: SELinux's osid no
longer records the sid of the thread that forked it.
(*) security_key_alloc(), ->key_alloc()
(*) security_key_permission(), ->key_permission()
Changed. These now take cred pointers rather than task pointers to
refer to the security context.
(4) sys_capset().
This has been simplified and uses less locking. The LSM functions it
calls have been merged.
(5) reparent_to_kthreadd().
This gives the current thread the same credentials as init by simply using
commit_thread() to point that way.
(6) __sigqueue_alloc() and switch_uid()
__sigqueue_alloc() can't stop the target task from changing its creds
beneath it, so this function gets a reference to the currently applicable
user_struct which it then passes into the sigqueue struct it returns if
successful.
switch_uid() is now called from commit_creds(), and possibly should be
folded into that. commit_creds() should take care of protecting
__sigqueue_alloc().
(7) [sg]et[ug]id() and co and [sg]et_current_groups.
The set functions now all use prepare_creds(), commit_creds() and
abort_creds() to build and check a new set of credentials before applying
it.
security_task_set[ug]id() is called inside the prepared section. This
guarantees that nothing else will affect the creds until we've finished.
The calling of set_dumpable() has been moved into commit_creds().
Much of the functionality of set_user() has been moved into
commit_creds().
The get functions all simply access the data directly.
(8) security_task_prctl() and cap_task_prctl().
security_task_prctl() has been modified to return -ENOSYS if it doesn't
want to handle a function, or otherwise return the return value directly
rather than through an argument.
Additionally, cap_task_prctl() now prepares a new set of credentials, even
if it doesn't end up using it.
(9) Keyrings.
A number of changes have been made to the keyrings code:
(a) switch_uid_keyring(), copy_keys(), exit_keys() and suid_keys() have
all been dropped and built in to the credentials functions directly.
They may want separating out again later.
(b) key_alloc() and search_process_keyrings() now take a cred pointer
rather than a task pointer to specify the security context.
(c) copy_creds() gives a new thread within the same thread group a new
thread keyring if its parent had one, otherwise it discards the thread
keyring.
(d) The authorisation key now points directly to the credentials to extend
the search into rather pointing to the task that carries them.
(e) Installing thread, process or session keyrings causes a new set of
credentials to be created, even though it's not strictly necessary for
process or session keyrings (they're shared).
(10) Usermode helper.
The usermode helper code now carries a cred struct pointer in its
subprocess_info struct instead of a new session keyring pointer. This set
of credentials is derived from init_cred and installed on the new process
after it has been cloned.
call_usermodehelper_setup() allocates the new credentials and
call_usermodehelper_freeinfo() discards them if they haven't been used. A
special cred function (prepare_usermodeinfo_creds()) is provided
specifically for call_usermodehelper_setup() to call.
call_usermodehelper_setkeys() adjusts the credentials to sport the
supplied keyring as the new session keyring.
(11) SELinux.
SELinux has a number of changes, in addition to those to support the LSM
interface changes mentioned above:
(a) selinux_setprocattr() no longer does its check for whether the
current ptracer can access processes with the new SID inside the lock
that covers getting the ptracer's SID. Whilst this lock ensures that
the check is done with the ptracer pinned, the result is only valid
until the lock is released, so there's no point doing it inside the
lock.
(12) is_single_threaded().
This function has been extracted from selinux_setprocattr() and put into
a file of its own in the lib/ directory as join_session_keyring() now
wants to use it too.
The code in SELinux just checked to see whether a task shared mm_structs
with other tasks (CLONE_VM), but that isn't good enough. We really want
to know if they're part of the same thread group (CLONE_THREAD).
(13) nfsd.
The NFS server daemon now has to use the COW credentials to set the
credentials it is going to use. It really needs to pass the credentials
down to the functions it calls, but it can't do that until other patches
in this series have been applied.
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: James Morris <jmorris@namei.org>
Signed-off-by: James Morris <jmorris@namei.org>
2008-11-13 23:39:23 +00:00
|
|
|
old_tsec = old->security;
|
2005-04-16 22:20:36 +00:00
|
|
|
|
CRED: Inaugurate COW credentials
Inaugurate copy-on-write credentials management. This uses RCU to manage the
credentials pointer in the task_struct with respect to accesses by other tasks.
A process may only modify its own credentials, and so does not need locking to
access or modify its own credentials.
A mutex (cred_replace_mutex) is added to the task_struct to control the effect
of PTRACE_ATTACHED on credential calculations, particularly with respect to
execve().
With this patch, the contents of an active credentials struct may not be
changed directly; rather a new set of credentials must be prepared, modified
and committed using something like the following sequence of events:
struct cred *new = prepare_creds();
int ret = blah(new);
if (ret < 0) {
abort_creds(new);
return ret;
}
return commit_creds(new);
There are some exceptions to this rule: the keyrings pointed to by the active
credentials may be instantiated - keyrings violate the COW rule as managing
COW keyrings is tricky, given that it is possible for a task to directly alter
the keys in a keyring in use by another task.
To help enforce this, various pointers to sets of credentials, such as those in
the task_struct, are declared const. The purpose of this is compile-time
discouragement of altering credentials through those pointers. Once a set of
credentials has been made public through one of these pointers, it may not be
modified, except under special circumstances:
(1) Its reference count may incremented and decremented.
(2) The keyrings to which it points may be modified, but not replaced.
The only safe way to modify anything else is to create a replacement and commit
using the functions described in Documentation/credentials.txt (which will be
added by a later patch).
This patch and the preceding patches have been tested with the LTP SELinux
testsuite.
This patch makes several logical sets of alteration:
(1) execve().
This now prepares and commits credentials in various places in the
security code rather than altering the current creds directly.
(2) Temporary credential overrides.
do_coredump() and sys_faccessat() now prepare their own credentials and
temporarily override the ones currently on the acting thread, whilst
preventing interference from other threads by holding cred_replace_mutex
on the thread being dumped.
This will be replaced in a future patch by something that hands down the
credentials directly to the functions being called, rather than altering
the task's objective credentials.
(3) LSM interface.
A number of functions have been changed, added or removed:
(*) security_capset_check(), ->capset_check()
(*) security_capset_set(), ->capset_set()
Removed in favour of security_capset().
(*) security_capset(), ->capset()
New. This is passed a pointer to the new creds, a pointer to the old
creds and the proposed capability sets. It should fill in the new
creds or return an error. All pointers, barring the pointer to the
new creds, are now const.
(*) security_bprm_apply_creds(), ->bprm_apply_creds()
Changed; now returns a value, which will cause the process to be
killed if it's an error.
(*) security_task_alloc(), ->task_alloc_security()
Removed in favour of security_prepare_creds().
(*) security_cred_free(), ->cred_free()
New. Free security data attached to cred->security.
(*) security_prepare_creds(), ->cred_prepare()
New. Duplicate any security data attached to cred->security.
(*) security_commit_creds(), ->cred_commit()
New. Apply any security effects for the upcoming installation of new
security by commit_creds().
(*) security_task_post_setuid(), ->task_post_setuid()
Removed in favour of security_task_fix_setuid().
(*) security_task_fix_setuid(), ->task_fix_setuid()
Fix up the proposed new credentials for setuid(). This is used by
cap_set_fix_setuid() to implicitly adjust capabilities in line with
setuid() changes. Changes are made to the new credentials, rather
than the task itself as in security_task_post_setuid().
(*) security_task_reparent_to_init(), ->task_reparent_to_init()
Removed. Instead the task being reparented to init is referred
directly to init's credentials.
NOTE! This results in the loss of some state: SELinux's osid no
longer records the sid of the thread that forked it.
(*) security_key_alloc(), ->key_alloc()
(*) security_key_permission(), ->key_permission()
Changed. These now take cred pointers rather than task pointers to
refer to the security context.
(4) sys_capset().
This has been simplified and uses less locking. The LSM functions it
calls have been merged.
(5) reparent_to_kthreadd().
This gives the current thread the same credentials as init by simply using
commit_thread() to point that way.
(6) __sigqueue_alloc() and switch_uid()
__sigqueue_alloc() can't stop the target task from changing its creds
beneath it, so this function gets a reference to the currently applicable
user_struct which it then passes into the sigqueue struct it returns if
successful.
switch_uid() is now called from commit_creds(), and possibly should be
folded into that. commit_creds() should take care of protecting
__sigqueue_alloc().
(7) [sg]et[ug]id() and co and [sg]et_current_groups.
The set functions now all use prepare_creds(), commit_creds() and
abort_creds() to build and check a new set of credentials before applying
it.
security_task_set[ug]id() is called inside the prepared section. This
guarantees that nothing else will affect the creds until we've finished.
The calling of set_dumpable() has been moved into commit_creds().
Much of the functionality of set_user() has been moved into
commit_creds().
The get functions all simply access the data directly.
(8) security_task_prctl() and cap_task_prctl().
security_task_prctl() has been modified to return -ENOSYS if it doesn't
want to handle a function, or otherwise return the return value directly
rather than through an argument.
Additionally, cap_task_prctl() now prepares a new set of credentials, even
if it doesn't end up using it.
(9) Keyrings.
A number of changes have been made to the keyrings code:
(a) switch_uid_keyring(), copy_keys(), exit_keys() and suid_keys() have
all been dropped and built in to the credentials functions directly.
They may want separating out again later.
(b) key_alloc() and search_process_keyrings() now take a cred pointer
rather than a task pointer to specify the security context.
(c) copy_creds() gives a new thread within the same thread group a new
thread keyring if its parent had one, otherwise it discards the thread
keyring.
(d) The authorisation key now points directly to the credentials to extend
the search into rather pointing to the task that carries them.
(e) Installing thread, process or session keyrings causes a new set of
credentials to be created, even though it's not strictly necessary for
process or session keyrings (they're shared).
(10) Usermode helper.
The usermode helper code now carries a cred struct pointer in its
subprocess_info struct instead of a new session keyring pointer. This set
of credentials is derived from init_cred and installed on the new process
after it has been cloned.
call_usermodehelper_setup() allocates the new credentials and
call_usermodehelper_freeinfo() discards them if they haven't been used. A
special cred function (prepare_usermodeinfo_creds()) is provided
specifically for call_usermodehelper_setup() to call.
call_usermodehelper_setkeys() adjusts the credentials to sport the
supplied keyring as the new session keyring.
(11) SELinux.
SELinux has a number of changes, in addition to those to support the LSM
interface changes mentioned above:
(a) selinux_setprocattr() no longer does its check for whether the
current ptracer can access processes with the new SID inside the lock
that covers getting the ptracer's SID. Whilst this lock ensures that
the check is done with the ptracer pinned, the result is only valid
until the lock is released, so there's no point doing it inside the
lock.
(12) is_single_threaded().
This function has been extracted from selinux_setprocattr() and put into
a file of its own in the lib/ directory as join_session_keyring() now
wants to use it too.
The code in SELinux just checked to see whether a task shared mm_structs
with other tasks (CLONE_VM), but that isn't good enough. We really want
to know if they're part of the same thread group (CLONE_THREAD).
(13) nfsd.
The NFS server daemon now has to use the COW credentials to set the
credentials it is going to use. It really needs to pass the credentials
down to the functions it calls, but it can't do that until other patches
in this series have been applied.
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: James Morris <jmorris@namei.org>
Signed-off-by: James Morris <jmorris@namei.org>
2008-11-13 23:39:23 +00:00
|
|
|
tsec = kmemdup(old_tsec, sizeof(struct task_security_struct), gfp);
|
|
|
|
if (!tsec)
|
|
|
|
return -ENOMEM;
|
2005-04-16 22:20:36 +00:00
|
|
|
|
CRED: Inaugurate COW credentials
Inaugurate copy-on-write credentials management. This uses RCU to manage the
credentials pointer in the task_struct with respect to accesses by other tasks.
A process may only modify its own credentials, and so does not need locking to
access or modify its own credentials.
A mutex (cred_replace_mutex) is added to the task_struct to control the effect
of PTRACE_ATTACHED on credential calculations, particularly with respect to
execve().
With this patch, the contents of an active credentials struct may not be
changed directly; rather a new set of credentials must be prepared, modified
and committed using something like the following sequence of events:
struct cred *new = prepare_creds();
int ret = blah(new);
if (ret < 0) {
abort_creds(new);
return ret;
}
return commit_creds(new);
There are some exceptions to this rule: the keyrings pointed to by the active
credentials may be instantiated - keyrings violate the COW rule as managing
COW keyrings is tricky, given that it is possible for a task to directly alter
the keys in a keyring in use by another task.
To help enforce this, various pointers to sets of credentials, such as those in
the task_struct, are declared const. The purpose of this is compile-time
discouragement of altering credentials through those pointers. Once a set of
credentials has been made public through one of these pointers, it may not be
modified, except under special circumstances:
(1) Its reference count may incremented and decremented.
(2) The keyrings to which it points may be modified, but not replaced.
The only safe way to modify anything else is to create a replacement and commit
using the functions described in Documentation/credentials.txt (which will be
added by a later patch).
This patch and the preceding patches have been tested with the LTP SELinux
testsuite.
This patch makes several logical sets of alteration:
(1) execve().
This now prepares and commits credentials in various places in the
security code rather than altering the current creds directly.
(2) Temporary credential overrides.
do_coredump() and sys_faccessat() now prepare their own credentials and
temporarily override the ones currently on the acting thread, whilst
preventing interference from other threads by holding cred_replace_mutex
on the thread being dumped.
This will be replaced in a future patch by something that hands down the
credentials directly to the functions being called, rather than altering
the task's objective credentials.
(3) LSM interface.
A number of functions have been changed, added or removed:
(*) security_capset_check(), ->capset_check()
(*) security_capset_set(), ->capset_set()
Removed in favour of security_capset().
(*) security_capset(), ->capset()
New. This is passed a pointer to the new creds, a pointer to the old
creds and the proposed capability sets. It should fill in the new
creds or return an error. All pointers, barring the pointer to the
new creds, are now const.
(*) security_bprm_apply_creds(), ->bprm_apply_creds()
Changed; now returns a value, which will cause the process to be
killed if it's an error.
(*) security_task_alloc(), ->task_alloc_security()
Removed in favour of security_prepare_creds().
(*) security_cred_free(), ->cred_free()
New. Free security data attached to cred->security.
(*) security_prepare_creds(), ->cred_prepare()
New. Duplicate any security data attached to cred->security.
(*) security_commit_creds(), ->cred_commit()
New. Apply any security effects for the upcoming installation of new
security by commit_creds().
(*) security_task_post_setuid(), ->task_post_setuid()
Removed in favour of security_task_fix_setuid().
(*) security_task_fix_setuid(), ->task_fix_setuid()
Fix up the proposed new credentials for setuid(). This is used by
cap_set_fix_setuid() to implicitly adjust capabilities in line with
setuid() changes. Changes are made to the new credentials, rather
than the task itself as in security_task_post_setuid().
(*) security_task_reparent_to_init(), ->task_reparent_to_init()
Removed. Instead the task being reparented to init is referred
directly to init's credentials.
NOTE! This results in the loss of some state: SELinux's osid no
longer records the sid of the thread that forked it.
(*) security_key_alloc(), ->key_alloc()
(*) security_key_permission(), ->key_permission()
Changed. These now take cred pointers rather than task pointers to
refer to the security context.
(4) sys_capset().
This has been simplified and uses less locking. The LSM functions it
calls have been merged.
(5) reparent_to_kthreadd().
This gives the current thread the same credentials as init by simply using
commit_thread() to point that way.
(6) __sigqueue_alloc() and switch_uid()
__sigqueue_alloc() can't stop the target task from changing its creds
beneath it, so this function gets a reference to the currently applicable
user_struct which it then passes into the sigqueue struct it returns if
successful.
switch_uid() is now called from commit_creds(), and possibly should be
folded into that. commit_creds() should take care of protecting
__sigqueue_alloc().
(7) [sg]et[ug]id() and co and [sg]et_current_groups.
The set functions now all use prepare_creds(), commit_creds() and
abort_creds() to build and check a new set of credentials before applying
it.
security_task_set[ug]id() is called inside the prepared section. This
guarantees that nothing else will affect the creds until we've finished.
The calling of set_dumpable() has been moved into commit_creds().
Much of the functionality of set_user() has been moved into
commit_creds().
The get functions all simply access the data directly.
(8) security_task_prctl() and cap_task_prctl().
security_task_prctl() has been modified to return -ENOSYS if it doesn't
want to handle a function, or otherwise return the return value directly
rather than through an argument.
Additionally, cap_task_prctl() now prepares a new set of credentials, even
if it doesn't end up using it.
(9) Keyrings.
A number of changes have been made to the keyrings code:
(a) switch_uid_keyring(), copy_keys(), exit_keys() and suid_keys() have
all been dropped and built in to the credentials functions directly.
They may want separating out again later.
(b) key_alloc() and search_process_keyrings() now take a cred pointer
rather than a task pointer to specify the security context.
(c) copy_creds() gives a new thread within the same thread group a new
thread keyring if its parent had one, otherwise it discards the thread
keyring.
(d) The authorisation key now points directly to the credentials to extend
the search into rather pointing to the task that carries them.
(e) Installing thread, process or session keyrings causes a new set of
credentials to be created, even though it's not strictly necessary for
process or session keyrings (they're shared).
(10) Usermode helper.
The usermode helper code now carries a cred struct pointer in its
subprocess_info struct instead of a new session keyring pointer. This set
of credentials is derived from init_cred and installed on the new process
after it has been cloned.
call_usermodehelper_setup() allocates the new credentials and
call_usermodehelper_freeinfo() discards them if they haven't been used. A
special cred function (prepare_usermodeinfo_creds()) is provided
specifically for call_usermodehelper_setup() to call.
call_usermodehelper_setkeys() adjusts the credentials to sport the
supplied keyring as the new session keyring.
(11) SELinux.
SELinux has a number of changes, in addition to those to support the LSM
interface changes mentioned above:
(a) selinux_setprocattr() no longer does its check for whether the
current ptracer can access processes with the new SID inside the lock
that covers getting the ptracer's SID. Whilst this lock ensures that
the check is done with the ptracer pinned, the result is only valid
until the lock is released, so there's no point doing it inside the
lock.
(12) is_single_threaded().
This function has been extracted from selinux_setprocattr() and put into
a file of its own in the lib/ directory as join_session_keyring() now
wants to use it too.
The code in SELinux just checked to see whether a task shared mm_structs
with other tasks (CLONE_VM), but that isn't good enough. We really want
to know if they're part of the same thread group (CLONE_THREAD).
(13) nfsd.
The NFS server daemon now has to use the COW credentials to set the
credentials it is going to use. It really needs to pass the credentials
down to the functions it calls, but it can't do that until other patches
in this series have been applied.
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: James Morris <jmorris@namei.org>
Signed-off-by: James Morris <jmorris@namei.org>
2008-11-13 23:39:23 +00:00
|
|
|
new->security = tsec;
|
2005-04-16 22:20:36 +00:00
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
KEYS: Add a keyctl to install a process's session keyring on its parent [try #6]
Add a keyctl to install a process's session keyring onto its parent. This
replaces the parent's session keyring. Because the COW credential code does
not permit one process to change another process's credentials directly, the
change is deferred until userspace next starts executing again. Normally this
will be after a wait*() syscall.
To support this, three new security hooks have been provided:
cred_alloc_blank() to allocate unset security creds, cred_transfer() to fill in
the blank security creds and key_session_to_parent() - which asks the LSM if
the process may replace its parent's session keyring.
The replacement may only happen if the process has the same ownership details
as its parent, and the process has LINK permission on the session keyring, and
the session keyring is owned by the process, and the LSM permits it.
Note that this requires alteration to each architecture's notify_resume path.
This has been done for all arches barring blackfin, m68k* and xtensa, all of
which need assembly alteration to support TIF_NOTIFY_RESUME. This allows the
replacement to be performed at the point the parent process resumes userspace
execution.
This allows the userspace AFS pioctl emulation to fully emulate newpag() and
the VIOCSETTOK and VIOCSETTOK2 pioctls, all of which require the ability to
alter the parent process's PAG membership. However, since kAFS doesn't use
PAGs per se, but rather dumps the keys into the session keyring, the session
keyring of the parent must be replaced if, for example, VIOCSETTOK is passed
the newpag flag.
This can be tested with the following program:
#include <stdio.h>
#include <stdlib.h>
#include <keyutils.h>
#define KEYCTL_SESSION_TO_PARENT 18
#define OSERROR(X, S) do { if ((long)(X) == -1) { perror(S); exit(1); } } while(0)
int main(int argc, char **argv)
{
key_serial_t keyring, key;
long ret;
keyring = keyctl_join_session_keyring(argv[1]);
OSERROR(keyring, "keyctl_join_session_keyring");
key = add_key("user", "a", "b", 1, keyring);
OSERROR(key, "add_key");
ret = keyctl(KEYCTL_SESSION_TO_PARENT);
OSERROR(ret, "KEYCTL_SESSION_TO_PARENT");
return 0;
}
Compiled and linked with -lkeyutils, you should see something like:
[dhowells@andromeda ~]$ keyctl show
Session Keyring
-3 --alswrv 4043 4043 keyring: _ses
355907932 --alswrv 4043 -1 \_ keyring: _uid.4043
[dhowells@andromeda ~]$ /tmp/newpag
[dhowells@andromeda ~]$ keyctl show
Session Keyring
-3 --alswrv 4043 4043 keyring: _ses
1055658746 --alswrv 4043 4043 \_ user: a
[dhowells@andromeda ~]$ /tmp/newpag hello
[dhowells@andromeda ~]$ keyctl show
Session Keyring
-3 --alswrv 4043 4043 keyring: hello
340417692 --alswrv 4043 4043 \_ user: a
Where the test program creates a new session keyring, sticks a user key named
'a' into it and then installs it on its parent.
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: James Morris <jmorris@namei.org>
2009-09-02 08:14:21 +00:00
|
|
|
/*
|
|
|
|
* transfer the SELinux data to a blank set of creds
|
|
|
|
*/
|
|
|
|
static void selinux_cred_transfer(struct cred *new, const struct cred *old)
|
|
|
|
{
|
|
|
|
const struct task_security_struct *old_tsec = old->security;
|
|
|
|
struct task_security_struct *tsec = new->security;
|
|
|
|
|
|
|
|
*tsec = *old_tsec;
|
|
|
|
}
|
|
|
|
|
2008-11-13 23:39:28 +00:00
|
|
|
/*
|
|
|
|
* set the security data for a kernel service
|
|
|
|
* - all the creation contexts are set to unlabelled
|
|
|
|
*/
|
|
|
|
static int selinux_kernel_act_as(struct cred *new, u32 secid)
|
|
|
|
{
|
|
|
|
struct task_security_struct *tsec = new->security;
|
|
|
|
u32 sid = current_sid();
|
|
|
|
int ret;
|
|
|
|
|
|
|
|
ret = avc_has_perm(sid, secid,
|
|
|
|
SECCLASS_KERNEL_SERVICE,
|
|
|
|
KERNEL_SERVICE__USE_AS_OVERRIDE,
|
|
|
|
NULL);
|
|
|
|
if (ret == 0) {
|
|
|
|
tsec->sid = secid;
|
|
|
|
tsec->create_sid = 0;
|
|
|
|
tsec->keycreate_sid = 0;
|
|
|
|
tsec->sockcreate_sid = 0;
|
|
|
|
}
|
|
|
|
return ret;
|
|
|
|
}
|
|
|
|
|
|
|
|
/*
|
|
|
|
* set the file creation context in a security record to the same as the
|
|
|
|
* objective context of the specified inode
|
|
|
|
*/
|
|
|
|
static int selinux_kernel_create_files_as(struct cred *new, struct inode *inode)
|
|
|
|
{
|
|
|
|
struct inode_security_struct *isec = inode->i_security;
|
|
|
|
struct task_security_struct *tsec = new->security;
|
|
|
|
u32 sid = current_sid();
|
|
|
|
int ret;
|
|
|
|
|
|
|
|
ret = avc_has_perm(sid, isec->sid,
|
|
|
|
SECCLASS_KERNEL_SERVICE,
|
|
|
|
KERNEL_SERVICE__CREATE_FILES_AS,
|
|
|
|
NULL);
|
|
|
|
|
|
|
|
if (ret == 0)
|
|
|
|
tsec->create_sid = isec->sid;
|
2010-02-26 01:56:16 +00:00
|
|
|
return ret;
|
2008-11-13 23:39:28 +00:00
|
|
|
}
|
|
|
|
|
2009-11-03 05:35:32 +00:00
|
|
|
static int selinux_kernel_module_request(char *kmod_name)
|
2009-08-13 13:45:03 +00:00
|
|
|
{
|
2009-11-03 05:35:32 +00:00
|
|
|
u32 sid;
|
|
|
|
struct common_audit_data ad;
|
|
|
|
|
|
|
|
sid = task_sid(current);
|
|
|
|
|
2012-04-04 19:01:43 +00:00
|
|
|
ad.type = LSM_AUDIT_DATA_KMOD;
|
2009-11-03 05:35:32 +00:00
|
|
|
ad.u.kmod_name = kmod_name;
|
|
|
|
|
|
|
|
return avc_has_perm(sid, SECINITSID_KERNEL, SECCLASS_SYSTEM,
|
|
|
|
SYSTEM__MODULE_REQUEST, &ad);
|
2009-08-13 13:45:03 +00:00
|
|
|
}
|
|
|
|
|
2005-04-16 22:20:36 +00:00
|
|
|
static int selinux_task_setpgid(struct task_struct *p, pid_t pgid)
|
|
|
|
{
|
2008-11-13 23:39:26 +00:00
|
|
|
return current_has_perm(p, PROCESS__SETPGID);
|
2005-04-16 22:20:36 +00:00
|
|
|
}
|
|
|
|
|
|
|
|
static int selinux_task_getpgid(struct task_struct *p)
|
|
|
|
{
|
2008-11-13 23:39:26 +00:00
|
|
|
return current_has_perm(p, PROCESS__GETPGID);
|
2005-04-16 22:20:36 +00:00
|
|
|
}
|
|
|
|
|
|
|
|
static int selinux_task_getsid(struct task_struct *p)
|
|
|
|
{
|
2008-11-13 23:39:26 +00:00
|
|
|
return current_has_perm(p, PROCESS__GETSESSION);
|
2005-04-16 22:20:36 +00:00
|
|
|
}
|
|
|
|
|
2006-06-30 08:55:46 +00:00
|
|
|
static void selinux_task_getsecid(struct task_struct *p, u32 *secid)
|
|
|
|
{
|
2008-11-13 23:39:19 +00:00
|
|
|
*secid = task_sid(p);
|
2006-06-30 08:55:46 +00:00
|
|
|
}
|
|
|
|
|
2005-04-16 22:20:36 +00:00
|
|
|
static int selinux_task_setnice(struct task_struct *p, int nice)
|
|
|
|
{
|
|
|
|
int rc;
|
|
|
|
|
2009-02-12 20:01:04 +00:00
|
|
|
rc = cap_task_setnice(p, nice);
|
2005-04-16 22:20:36 +00:00
|
|
|
if (rc)
|
|
|
|
return rc;
|
|
|
|
|
2008-11-13 23:39:26 +00:00
|
|
|
return current_has_perm(p, PROCESS__SETSCHED);
|
2005-04-16 22:20:36 +00:00
|
|
|
}
|
|
|
|
|
2006-06-23 09:03:58 +00:00
|
|
|
static int selinux_task_setioprio(struct task_struct *p, int ioprio)
|
|
|
|
{
|
Implement file posix capabilities
Implement file posix capabilities. This allows programs to be given a
subset of root's powers regardless of who runs them, without having to use
setuid and giving the binary all of root's powers.
This version works with Kaigai Kohei's userspace tools, found at
http://www.kaigai.gr.jp/index.php. For more information on how to use this
patch, Chris Friedhoff has posted a nice page at
http://www.friedhoff.org/fscaps.html.
Changelog:
Nov 27:
Incorporate fixes from Andrew Morton
(security-introduce-file-caps-tweaks and
security-introduce-file-caps-warning-fix)
Fix Kconfig dependency.
Fix change signaling behavior when file caps are not compiled in.
Nov 13:
Integrate comments from Alexey: Remove CONFIG_ ifdef from
capability.h, and use %zd for printing a size_t.
Nov 13:
Fix endianness warnings by sparse as suggested by Alexey
Dobriyan.
Nov 09:
Address warnings of unused variables at cap_bprm_set_security
when file capabilities are disabled, and simultaneously clean
up the code a little, by pulling the new code into a helper
function.
Nov 08:
For pointers to required userspace tools and how to use
them, see http://www.friedhoff.org/fscaps.html.
Nov 07:
Fix the calculation of the highest bit checked in
check_cap_sanity().
Nov 07:
Allow file caps to be enabled without CONFIG_SECURITY, since
capabilities are the default.
Hook cap_task_setscheduler when !CONFIG_SECURITY.
Move capable(TASK_KILL) to end of cap_task_kill to reduce
audit messages.
Nov 05:
Add secondary calls in selinux/hooks.c to task_setioprio and
task_setscheduler so that selinux and capabilities with file
cap support can be stacked.
Sep 05:
As Seth Arnold points out, uid checks are out of place
for capability code.
Sep 01:
Define task_setscheduler, task_setioprio, cap_task_kill, and
task_setnice to make sure a user cannot affect a process in which
they called a program with some fscaps.
One remaining question is the note under task_setscheduler: are we
ok with CAP_SYS_NICE being sufficient to confine a process to a
cpuset?
It is a semantic change, as without fsccaps, attach_task doesn't
allow CAP_SYS_NICE to override the uid equivalence check. But since
it uses security_task_setscheduler, which elsewhere is used where
CAP_SYS_NICE can be used to override the uid equivalence check,
fixing it might be tough.
task_setscheduler
note: this also controls cpuset:attach_task. Are we ok with
CAP_SYS_NICE being used to confine to a cpuset?
task_setioprio
task_setnice
sys_setpriority uses this (through set_one_prio) for another
process. Need same checks as setrlimit
Aug 21:
Updated secureexec implementation to reflect the fact that
euid and uid might be the same and nonzero, but the process
might still have elevated caps.
Aug 15:
Handle endianness of xattrs.
Enforce capability version match between kernel and disk.
Enforce that no bits beyond the known max capability are
set, else return -EPERM.
With this extra processing, it may be worth reconsidering
doing all the work at bprm_set_security rather than
d_instantiate.
Aug 10:
Always call getxattr at bprm_set_security, rather than
caching it at d_instantiate.
[morgan@kernel.org: file-caps clean up for linux/capability.h]
[bunk@kernel.org: unexport cap_inode_killpriv]
Signed-off-by: Serge E. Hallyn <serue@us.ibm.com>
Cc: Stephen Smalley <sds@tycho.nsa.gov>
Cc: James Morris <jmorris@namei.org>
Cc: Chris Wright <chrisw@sous-sol.org>
Cc: Andrew Morgan <morgan@kernel.org>
Signed-off-by: Andrew Morgan <morgan@kernel.org>
Signed-off-by: Adrian Bunk <bunk@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-17 06:31:36 +00:00
|
|
|
int rc;
|
|
|
|
|
2009-02-12 20:01:04 +00:00
|
|
|
rc = cap_task_setioprio(p, ioprio);
|
Implement file posix capabilities
Implement file posix capabilities. This allows programs to be given a
subset of root's powers regardless of who runs them, without having to use
setuid and giving the binary all of root's powers.
This version works with Kaigai Kohei's userspace tools, found at
http://www.kaigai.gr.jp/index.php. For more information on how to use this
patch, Chris Friedhoff has posted a nice page at
http://www.friedhoff.org/fscaps.html.
Changelog:
Nov 27:
Incorporate fixes from Andrew Morton
(security-introduce-file-caps-tweaks and
security-introduce-file-caps-warning-fix)
Fix Kconfig dependency.
Fix change signaling behavior when file caps are not compiled in.
Nov 13:
Integrate comments from Alexey: Remove CONFIG_ ifdef from
capability.h, and use %zd for printing a size_t.
Nov 13:
Fix endianness warnings by sparse as suggested by Alexey
Dobriyan.
Nov 09:
Address warnings of unused variables at cap_bprm_set_security
when file capabilities are disabled, and simultaneously clean
up the code a little, by pulling the new code into a helper
function.
Nov 08:
For pointers to required userspace tools and how to use
them, see http://www.friedhoff.org/fscaps.html.
Nov 07:
Fix the calculation of the highest bit checked in
check_cap_sanity().
Nov 07:
Allow file caps to be enabled without CONFIG_SECURITY, since
capabilities are the default.
Hook cap_task_setscheduler when !CONFIG_SECURITY.
Move capable(TASK_KILL) to end of cap_task_kill to reduce
audit messages.
Nov 05:
Add secondary calls in selinux/hooks.c to task_setioprio and
task_setscheduler so that selinux and capabilities with file
cap support can be stacked.
Sep 05:
As Seth Arnold points out, uid checks are out of place
for capability code.
Sep 01:
Define task_setscheduler, task_setioprio, cap_task_kill, and
task_setnice to make sure a user cannot affect a process in which
they called a program with some fscaps.
One remaining question is the note under task_setscheduler: are we
ok with CAP_SYS_NICE being sufficient to confine a process to a
cpuset?
It is a semantic change, as without fsccaps, attach_task doesn't
allow CAP_SYS_NICE to override the uid equivalence check. But since
it uses security_task_setscheduler, which elsewhere is used where
CAP_SYS_NICE can be used to override the uid equivalence check,
fixing it might be tough.
task_setscheduler
note: this also controls cpuset:attach_task. Are we ok with
CAP_SYS_NICE being used to confine to a cpuset?
task_setioprio
task_setnice
sys_setpriority uses this (through set_one_prio) for another
process. Need same checks as setrlimit
Aug 21:
Updated secureexec implementation to reflect the fact that
euid and uid might be the same and nonzero, but the process
might still have elevated caps.
Aug 15:
Handle endianness of xattrs.
Enforce capability version match between kernel and disk.
Enforce that no bits beyond the known max capability are
set, else return -EPERM.
With this extra processing, it may be worth reconsidering
doing all the work at bprm_set_security rather than
d_instantiate.
Aug 10:
Always call getxattr at bprm_set_security, rather than
caching it at d_instantiate.
[morgan@kernel.org: file-caps clean up for linux/capability.h]
[bunk@kernel.org: unexport cap_inode_killpriv]
Signed-off-by: Serge E. Hallyn <serue@us.ibm.com>
Cc: Stephen Smalley <sds@tycho.nsa.gov>
Cc: James Morris <jmorris@namei.org>
Cc: Chris Wright <chrisw@sous-sol.org>
Cc: Andrew Morgan <morgan@kernel.org>
Signed-off-by: Andrew Morgan <morgan@kernel.org>
Signed-off-by: Adrian Bunk <bunk@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-17 06:31:36 +00:00
|
|
|
if (rc)
|
|
|
|
return rc;
|
|
|
|
|
2008-11-13 23:39:26 +00:00
|
|
|
return current_has_perm(p, PROCESS__SETSCHED);
|
2006-06-23 09:03:58 +00:00
|
|
|
}
|
|
|
|
|
2006-06-30 08:55:49 +00:00
|
|
|
static int selinux_task_getioprio(struct task_struct *p)
|
|
|
|
{
|
2008-11-13 23:39:26 +00:00
|
|
|
return current_has_perm(p, PROCESS__GETSCHED);
|
2006-06-30 08:55:49 +00:00
|
|
|
}
|
|
|
|
|
2009-08-26 16:41:16 +00:00
|
|
|
static int selinux_task_setrlimit(struct task_struct *p, unsigned int resource,
|
|
|
|
struct rlimit *new_rlim)
|
2005-04-16 22:20:36 +00:00
|
|
|
{
|
2009-08-26 16:41:16 +00:00
|
|
|
struct rlimit *old_rlim = p->signal->rlim + resource;
|
2005-04-16 22:20:36 +00:00
|
|
|
|
|
|
|
/* Control the ability to change the hard limit (whether
|
|
|
|
lowering or raising it), so that the hard limit can
|
|
|
|
later be used as a safe reset point for the soft limit
|
CRED: Inaugurate COW credentials
Inaugurate copy-on-write credentials management. This uses RCU to manage the
credentials pointer in the task_struct with respect to accesses by other tasks.
A process may only modify its own credentials, and so does not need locking to
access or modify its own credentials.
A mutex (cred_replace_mutex) is added to the task_struct to control the effect
of PTRACE_ATTACHED on credential calculations, particularly with respect to
execve().
With this patch, the contents of an active credentials struct may not be
changed directly; rather a new set of credentials must be prepared, modified
and committed using something like the following sequence of events:
struct cred *new = prepare_creds();
int ret = blah(new);
if (ret < 0) {
abort_creds(new);
return ret;
}
return commit_creds(new);
There are some exceptions to this rule: the keyrings pointed to by the active
credentials may be instantiated - keyrings violate the COW rule as managing
COW keyrings is tricky, given that it is possible for a task to directly alter
the keys in a keyring in use by another task.
To help enforce this, various pointers to sets of credentials, such as those in
the task_struct, are declared const. The purpose of this is compile-time
discouragement of altering credentials through those pointers. Once a set of
credentials has been made public through one of these pointers, it may not be
modified, except under special circumstances:
(1) Its reference count may incremented and decremented.
(2) The keyrings to which it points may be modified, but not replaced.
The only safe way to modify anything else is to create a replacement and commit
using the functions described in Documentation/credentials.txt (which will be
added by a later patch).
This patch and the preceding patches have been tested with the LTP SELinux
testsuite.
This patch makes several logical sets of alteration:
(1) execve().
This now prepares and commits credentials in various places in the
security code rather than altering the current creds directly.
(2) Temporary credential overrides.
do_coredump() and sys_faccessat() now prepare their own credentials and
temporarily override the ones currently on the acting thread, whilst
preventing interference from other threads by holding cred_replace_mutex
on the thread being dumped.
This will be replaced in a future patch by something that hands down the
credentials directly to the functions being called, rather than altering
the task's objective credentials.
(3) LSM interface.
A number of functions have been changed, added or removed:
(*) security_capset_check(), ->capset_check()
(*) security_capset_set(), ->capset_set()
Removed in favour of security_capset().
(*) security_capset(), ->capset()
New. This is passed a pointer to the new creds, a pointer to the old
creds and the proposed capability sets. It should fill in the new
creds or return an error. All pointers, barring the pointer to the
new creds, are now const.
(*) security_bprm_apply_creds(), ->bprm_apply_creds()
Changed; now returns a value, which will cause the process to be
killed if it's an error.
(*) security_task_alloc(), ->task_alloc_security()
Removed in favour of security_prepare_creds().
(*) security_cred_free(), ->cred_free()
New. Free security data attached to cred->security.
(*) security_prepare_creds(), ->cred_prepare()
New. Duplicate any security data attached to cred->security.
(*) security_commit_creds(), ->cred_commit()
New. Apply any security effects for the upcoming installation of new
security by commit_creds().
(*) security_task_post_setuid(), ->task_post_setuid()
Removed in favour of security_task_fix_setuid().
(*) security_task_fix_setuid(), ->task_fix_setuid()
Fix up the proposed new credentials for setuid(). This is used by
cap_set_fix_setuid() to implicitly adjust capabilities in line with
setuid() changes. Changes are made to the new credentials, rather
than the task itself as in security_task_post_setuid().
(*) security_task_reparent_to_init(), ->task_reparent_to_init()
Removed. Instead the task being reparented to init is referred
directly to init's credentials.
NOTE! This results in the loss of some state: SELinux's osid no
longer records the sid of the thread that forked it.
(*) security_key_alloc(), ->key_alloc()
(*) security_key_permission(), ->key_permission()
Changed. These now take cred pointers rather than task pointers to
refer to the security context.
(4) sys_capset().
This has been simplified and uses less locking. The LSM functions it
calls have been merged.
(5) reparent_to_kthreadd().
This gives the current thread the same credentials as init by simply using
commit_thread() to point that way.
(6) __sigqueue_alloc() and switch_uid()
__sigqueue_alloc() can't stop the target task from changing its creds
beneath it, so this function gets a reference to the currently applicable
user_struct which it then passes into the sigqueue struct it returns if
successful.
switch_uid() is now called from commit_creds(), and possibly should be
folded into that. commit_creds() should take care of protecting
__sigqueue_alloc().
(7) [sg]et[ug]id() and co and [sg]et_current_groups.
The set functions now all use prepare_creds(), commit_creds() and
abort_creds() to build and check a new set of credentials before applying
it.
security_task_set[ug]id() is called inside the prepared section. This
guarantees that nothing else will affect the creds until we've finished.
The calling of set_dumpable() has been moved into commit_creds().
Much of the functionality of set_user() has been moved into
commit_creds().
The get functions all simply access the data directly.
(8) security_task_prctl() and cap_task_prctl().
security_task_prctl() has been modified to return -ENOSYS if it doesn't
want to handle a function, or otherwise return the return value directly
rather than through an argument.
Additionally, cap_task_prctl() now prepares a new set of credentials, even
if it doesn't end up using it.
(9) Keyrings.
A number of changes have been made to the keyrings code:
(a) switch_uid_keyring(), copy_keys(), exit_keys() and suid_keys() have
all been dropped and built in to the credentials functions directly.
They may want separating out again later.
(b) key_alloc() and search_process_keyrings() now take a cred pointer
rather than a task pointer to specify the security context.
(c) copy_creds() gives a new thread within the same thread group a new
thread keyring if its parent had one, otherwise it discards the thread
keyring.
(d) The authorisation key now points directly to the credentials to extend
the search into rather pointing to the task that carries them.
(e) Installing thread, process or session keyrings causes a new set of
credentials to be created, even though it's not strictly necessary for
process or session keyrings (they're shared).
(10) Usermode helper.
The usermode helper code now carries a cred struct pointer in its
subprocess_info struct instead of a new session keyring pointer. This set
of credentials is derived from init_cred and installed on the new process
after it has been cloned.
call_usermodehelper_setup() allocates the new credentials and
call_usermodehelper_freeinfo() discards them if they haven't been used. A
special cred function (prepare_usermodeinfo_creds()) is provided
specifically for call_usermodehelper_setup() to call.
call_usermodehelper_setkeys() adjusts the credentials to sport the
supplied keyring as the new session keyring.
(11) SELinux.
SELinux has a number of changes, in addition to those to support the LSM
interface changes mentioned above:
(a) selinux_setprocattr() no longer does its check for whether the
current ptracer can access processes with the new SID inside the lock
that covers getting the ptracer's SID. Whilst this lock ensures that
the check is done with the ptracer pinned, the result is only valid
until the lock is released, so there's no point doing it inside the
lock.
(12) is_single_threaded().
This function has been extracted from selinux_setprocattr() and put into
a file of its own in the lib/ directory as join_session_keyring() now
wants to use it too.
The code in SELinux just checked to see whether a task shared mm_structs
with other tasks (CLONE_VM), but that isn't good enough. We really want
to know if they're part of the same thread group (CLONE_THREAD).
(13) nfsd.
The NFS server daemon now has to use the COW credentials to set the
credentials it is going to use. It really needs to pass the credentials
down to the functions it calls, but it can't do that until other patches
in this series have been applied.
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: James Morris <jmorris@namei.org>
Signed-off-by: James Morris <jmorris@namei.org>
2008-11-13 23:39:23 +00:00
|
|
|
upon context transitions. See selinux_bprm_committing_creds. */
|
2005-04-16 22:20:36 +00:00
|
|
|
if (old_rlim->rlim_max != new_rlim->rlim_max)
|
2009-08-26 16:41:16 +00:00
|
|
|
return current_has_perm(p, PROCESS__SETRLIMIT);
|
2005-04-16 22:20:36 +00:00
|
|
|
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
2010-10-14 19:21:18 +00:00
|
|
|
static int selinux_task_setscheduler(struct task_struct *p)
|
2005-04-16 22:20:36 +00:00
|
|
|
{
|
Implement file posix capabilities
Implement file posix capabilities. This allows programs to be given a
subset of root's powers regardless of who runs them, without having to use
setuid and giving the binary all of root's powers.
This version works with Kaigai Kohei's userspace tools, found at
http://www.kaigai.gr.jp/index.php. For more information on how to use this
patch, Chris Friedhoff has posted a nice page at
http://www.friedhoff.org/fscaps.html.
Changelog:
Nov 27:
Incorporate fixes from Andrew Morton
(security-introduce-file-caps-tweaks and
security-introduce-file-caps-warning-fix)
Fix Kconfig dependency.
Fix change signaling behavior when file caps are not compiled in.
Nov 13:
Integrate comments from Alexey: Remove CONFIG_ ifdef from
capability.h, and use %zd for printing a size_t.
Nov 13:
Fix endianness warnings by sparse as suggested by Alexey
Dobriyan.
Nov 09:
Address warnings of unused variables at cap_bprm_set_security
when file capabilities are disabled, and simultaneously clean
up the code a little, by pulling the new code into a helper
function.
Nov 08:
For pointers to required userspace tools and how to use
them, see http://www.friedhoff.org/fscaps.html.
Nov 07:
Fix the calculation of the highest bit checked in
check_cap_sanity().
Nov 07:
Allow file caps to be enabled without CONFIG_SECURITY, since
capabilities are the default.
Hook cap_task_setscheduler when !CONFIG_SECURITY.
Move capable(TASK_KILL) to end of cap_task_kill to reduce
audit messages.
Nov 05:
Add secondary calls in selinux/hooks.c to task_setioprio and
task_setscheduler so that selinux and capabilities with file
cap support can be stacked.
Sep 05:
As Seth Arnold points out, uid checks are out of place
for capability code.
Sep 01:
Define task_setscheduler, task_setioprio, cap_task_kill, and
task_setnice to make sure a user cannot affect a process in which
they called a program with some fscaps.
One remaining question is the note under task_setscheduler: are we
ok with CAP_SYS_NICE being sufficient to confine a process to a
cpuset?
It is a semantic change, as without fsccaps, attach_task doesn't
allow CAP_SYS_NICE to override the uid equivalence check. But since
it uses security_task_setscheduler, which elsewhere is used where
CAP_SYS_NICE can be used to override the uid equivalence check,
fixing it might be tough.
task_setscheduler
note: this also controls cpuset:attach_task. Are we ok with
CAP_SYS_NICE being used to confine to a cpuset?
task_setioprio
task_setnice
sys_setpriority uses this (through set_one_prio) for another
process. Need same checks as setrlimit
Aug 21:
Updated secureexec implementation to reflect the fact that
euid and uid might be the same and nonzero, but the process
might still have elevated caps.
Aug 15:
Handle endianness of xattrs.
Enforce capability version match between kernel and disk.
Enforce that no bits beyond the known max capability are
set, else return -EPERM.
With this extra processing, it may be worth reconsidering
doing all the work at bprm_set_security rather than
d_instantiate.
Aug 10:
Always call getxattr at bprm_set_security, rather than
caching it at d_instantiate.
[morgan@kernel.org: file-caps clean up for linux/capability.h]
[bunk@kernel.org: unexport cap_inode_killpriv]
Signed-off-by: Serge E. Hallyn <serue@us.ibm.com>
Cc: Stephen Smalley <sds@tycho.nsa.gov>
Cc: James Morris <jmorris@namei.org>
Cc: Chris Wright <chrisw@sous-sol.org>
Cc: Andrew Morgan <morgan@kernel.org>
Signed-off-by: Andrew Morgan <morgan@kernel.org>
Signed-off-by: Adrian Bunk <bunk@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-17 06:31:36 +00:00
|
|
|
int rc;
|
|
|
|
|
2010-10-14 19:21:18 +00:00
|
|
|
rc = cap_task_setscheduler(p);
|
Implement file posix capabilities
Implement file posix capabilities. This allows programs to be given a
subset of root's powers regardless of who runs them, without having to use
setuid and giving the binary all of root's powers.
This version works with Kaigai Kohei's userspace tools, found at
http://www.kaigai.gr.jp/index.php. For more information on how to use this
patch, Chris Friedhoff has posted a nice page at
http://www.friedhoff.org/fscaps.html.
Changelog:
Nov 27:
Incorporate fixes from Andrew Morton
(security-introduce-file-caps-tweaks and
security-introduce-file-caps-warning-fix)
Fix Kconfig dependency.
Fix change signaling behavior when file caps are not compiled in.
Nov 13:
Integrate comments from Alexey: Remove CONFIG_ ifdef from
capability.h, and use %zd for printing a size_t.
Nov 13:
Fix endianness warnings by sparse as suggested by Alexey
Dobriyan.
Nov 09:
Address warnings of unused variables at cap_bprm_set_security
when file capabilities are disabled, and simultaneously clean
up the code a little, by pulling the new code into a helper
function.
Nov 08:
For pointers to required userspace tools and how to use
them, see http://www.friedhoff.org/fscaps.html.
Nov 07:
Fix the calculation of the highest bit checked in
check_cap_sanity().
Nov 07:
Allow file caps to be enabled without CONFIG_SECURITY, since
capabilities are the default.
Hook cap_task_setscheduler when !CONFIG_SECURITY.
Move capable(TASK_KILL) to end of cap_task_kill to reduce
audit messages.
Nov 05:
Add secondary calls in selinux/hooks.c to task_setioprio and
task_setscheduler so that selinux and capabilities with file
cap support can be stacked.
Sep 05:
As Seth Arnold points out, uid checks are out of place
for capability code.
Sep 01:
Define task_setscheduler, task_setioprio, cap_task_kill, and
task_setnice to make sure a user cannot affect a process in which
they called a program with some fscaps.
One remaining question is the note under task_setscheduler: are we
ok with CAP_SYS_NICE being sufficient to confine a process to a
cpuset?
It is a semantic change, as without fsccaps, attach_task doesn't
allow CAP_SYS_NICE to override the uid equivalence check. But since
it uses security_task_setscheduler, which elsewhere is used where
CAP_SYS_NICE can be used to override the uid equivalence check,
fixing it might be tough.
task_setscheduler
note: this also controls cpuset:attach_task. Are we ok with
CAP_SYS_NICE being used to confine to a cpuset?
task_setioprio
task_setnice
sys_setpriority uses this (through set_one_prio) for another
process. Need same checks as setrlimit
Aug 21:
Updated secureexec implementation to reflect the fact that
euid and uid might be the same and nonzero, but the process
might still have elevated caps.
Aug 15:
Handle endianness of xattrs.
Enforce capability version match between kernel and disk.
Enforce that no bits beyond the known max capability are
set, else return -EPERM.
With this extra processing, it may be worth reconsidering
doing all the work at bprm_set_security rather than
d_instantiate.
Aug 10:
Always call getxattr at bprm_set_security, rather than
caching it at d_instantiate.
[morgan@kernel.org: file-caps clean up for linux/capability.h]
[bunk@kernel.org: unexport cap_inode_killpriv]
Signed-off-by: Serge E. Hallyn <serue@us.ibm.com>
Cc: Stephen Smalley <sds@tycho.nsa.gov>
Cc: James Morris <jmorris@namei.org>
Cc: Chris Wright <chrisw@sous-sol.org>
Cc: Andrew Morgan <morgan@kernel.org>
Signed-off-by: Andrew Morgan <morgan@kernel.org>
Signed-off-by: Adrian Bunk <bunk@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-17 06:31:36 +00:00
|
|
|
if (rc)
|
|
|
|
return rc;
|
|
|
|
|
2008-11-13 23:39:26 +00:00
|
|
|
return current_has_perm(p, PROCESS__SETSCHED);
|
2005-04-16 22:20:36 +00:00
|
|
|
}
|
|
|
|
|
|
|
|
static int selinux_task_getscheduler(struct task_struct *p)
|
|
|
|
{
|
2008-11-13 23:39:26 +00:00
|
|
|
return current_has_perm(p, PROCESS__GETSCHED);
|
2005-04-16 22:20:36 +00:00
|
|
|
}
|
|
|
|
|
2006-06-23 09:04:01 +00:00
|
|
|
static int selinux_task_movememory(struct task_struct *p)
|
|
|
|
{
|
2008-11-13 23:39:26 +00:00
|
|
|
return current_has_perm(p, PROCESS__SETSCHED);
|
2006-06-23 09:04:01 +00:00
|
|
|
}
|
|
|
|
|
2006-06-30 08:55:46 +00:00
|
|
|
static int selinux_task_kill(struct task_struct *p, struct siginfo *info,
|
|
|
|
int sig, u32 secid)
|
2005-04-16 22:20:36 +00:00
|
|
|
{
|
|
|
|
u32 perm;
|
|
|
|
int rc;
|
|
|
|
|
|
|
|
if (!sig)
|
|
|
|
perm = PROCESS__SIGNULL; /* null signal; existence test */
|
|
|
|
else
|
|
|
|
perm = signal_to_av(sig);
|
2006-06-30 08:55:46 +00:00
|
|
|
if (secid)
|
2008-11-13 23:39:19 +00:00
|
|
|
rc = avc_has_perm(secid, task_sid(p),
|
|
|
|
SECCLASS_PROCESS, perm, NULL);
|
2006-06-30 08:55:46 +00:00
|
|
|
else
|
2008-11-13 23:39:26 +00:00
|
|
|
rc = current_has_perm(p, perm);
|
2006-06-30 08:55:46 +00:00
|
|
|
return rc;
|
2005-04-16 22:20:36 +00:00
|
|
|
}
|
|
|
|
|
|
|
|
static int selinux_task_wait(struct task_struct *p)
|
|
|
|
{
|
2007-10-22 20:10:31 +00:00
|
|
|
return task_has_perm(p, current, PROCESS__SIGCHLD);
|
2005-04-16 22:20:36 +00:00
|
|
|
}
|
|
|
|
|
|
|
|
static void selinux_task_to_inode(struct task_struct *p,
|
|
|
|
struct inode *inode)
|
|
|
|
{
|
|
|
|
struct inode_security_struct *isec = inode->i_security;
|
2008-11-13 23:39:19 +00:00
|
|
|
u32 sid = task_sid(p);
|
2005-04-16 22:20:36 +00:00
|
|
|
|
2008-11-13 23:39:19 +00:00
|
|
|
isec->sid = sid;
|
2005-04-16 22:20:36 +00:00
|
|
|
isec->initialized = 1;
|
|
|
|
}
|
|
|
|
|
|
|
|
/* Returns error only if unable to parse addresses */
|
2006-11-08 23:04:26 +00:00
|
|
|
static int selinux_parse_skb_ipv4(struct sk_buff *skb,
|
2009-07-14 16:14:09 +00:00
|
|
|
struct common_audit_data *ad, u8 *proto)
|
2005-04-16 22:20:36 +00:00
|
|
|
{
|
|
|
|
int offset, ihlen, ret = -EINVAL;
|
|
|
|
struct iphdr _iph, *ih;
|
|
|
|
|
2007-03-11 01:16:10 +00:00
|
|
|
offset = skb_network_offset(skb);
|
2005-04-16 22:20:36 +00:00
|
|
|
ih = skb_header_pointer(skb, offset, sizeof(_iph), &_iph);
|
|
|
|
if (ih == NULL)
|
|
|
|
goto out;
|
|
|
|
|
|
|
|
ihlen = ih->ihl * 4;
|
|
|
|
if (ihlen < sizeof(_iph))
|
|
|
|
goto out;
|
|
|
|
|
2012-04-02 17:15:44 +00:00
|
|
|
ad->u.net->v4info.saddr = ih->saddr;
|
|
|
|
ad->u.net->v4info.daddr = ih->daddr;
|
2005-04-16 22:20:36 +00:00
|
|
|
ret = 0;
|
|
|
|
|
2006-11-08 23:04:26 +00:00
|
|
|
if (proto)
|
|
|
|
*proto = ih->protocol;
|
|
|
|
|
2005-04-16 22:20:36 +00:00
|
|
|
switch (ih->protocol) {
|
2008-04-17 17:17:49 +00:00
|
|
|
case IPPROTO_TCP: {
|
|
|
|
struct tcphdr _tcph, *th;
|
2005-04-16 22:20:36 +00:00
|
|
|
|
2008-04-17 17:17:49 +00:00
|
|
|
if (ntohs(ih->frag_off) & IP_OFFSET)
|
|
|
|
break;
|
2005-04-16 22:20:36 +00:00
|
|
|
|
|
|
|
offset += ihlen;
|
|
|
|
th = skb_header_pointer(skb, offset, sizeof(_tcph), &_tcph);
|
|
|
|
if (th == NULL)
|
|
|
|
break;
|
|
|
|
|
2012-04-02 17:15:44 +00:00
|
|
|
ad->u.net->sport = th->source;
|
|
|
|
ad->u.net->dport = th->dest;
|
2005-04-16 22:20:36 +00:00
|
|
|
break;
|
2008-04-17 17:17:49 +00:00
|
|
|
}
|
|
|
|
|
|
|
|
case IPPROTO_UDP: {
|
|
|
|
struct udphdr _udph, *uh;
|
|
|
|
|
|
|
|
if (ntohs(ih->frag_off) & IP_OFFSET)
|
|
|
|
break;
|
|
|
|
|
2005-04-16 22:20:36 +00:00
|
|
|
offset += ihlen;
|
2008-04-17 17:17:49 +00:00
|
|
|
uh = skb_header_pointer(skb, offset, sizeof(_udph), &_udph);
|
2005-04-16 22:20:36 +00:00
|
|
|
if (uh == NULL)
|
2008-04-17 17:17:49 +00:00
|
|
|
break;
|
2005-04-16 22:20:36 +00:00
|
|
|
|
2012-04-02 17:15:44 +00:00
|
|
|
ad->u.net->sport = uh->source;
|
|
|
|
ad->u.net->dport = uh->dest;
|
2008-04-17 17:17:49 +00:00
|
|
|
break;
|
|
|
|
}
|
2005-04-16 22:20:36 +00:00
|
|
|
|
2006-11-14 00:09:01 +00:00
|
|
|
case IPPROTO_DCCP: {
|
|
|
|
struct dccp_hdr _dccph, *dh;
|
|
|
|
|
|
|
|
if (ntohs(ih->frag_off) & IP_OFFSET)
|
|
|
|
break;
|
|
|
|
|
|
|
|
offset += ihlen;
|
|
|
|
dh = skb_header_pointer(skb, offset, sizeof(_dccph), &_dccph);
|
|
|
|
if (dh == NULL)
|
|
|
|
break;
|
|
|
|
|
2012-04-02 17:15:44 +00:00
|
|
|
ad->u.net->sport = dh->dccph_sport;
|
|
|
|
ad->u.net->dport = dh->dccph_dport;
|
2006-11-14 00:09:01 +00:00
|
|
|
break;
|
2008-04-17 17:17:49 +00:00
|
|
|
}
|
2006-11-14 00:09:01 +00:00
|
|
|
|
2008-04-17 17:17:49 +00:00
|
|
|
default:
|
|
|
|
break;
|
|
|
|
}
|
2005-04-16 22:20:36 +00:00
|
|
|
out:
|
|
|
|
return ret;
|
|
|
|
}
|
|
|
|
|
|
|
|
#if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
|
|
|
|
|
|
|
|
/* Returns error only if unable to parse addresses */
|
2006-11-08 23:04:26 +00:00
|
|
|
static int selinux_parse_skb_ipv6(struct sk_buff *skb,
|
2009-07-14 16:14:09 +00:00
|
|
|
struct common_audit_data *ad, u8 *proto)
|
2005-04-16 22:20:36 +00:00
|
|
|
{
|
|
|
|
u8 nexthdr;
|
|
|
|
int ret = -EINVAL, offset;
|
|
|
|
struct ipv6hdr _ipv6h, *ip6;
|
2011-12-01 01:05:51 +00:00
|
|
|
__be16 frag_off;
|
2005-04-16 22:20:36 +00:00
|
|
|
|
2007-03-11 01:16:10 +00:00
|
|
|
offset = skb_network_offset(skb);
|
2005-04-16 22:20:36 +00:00
|
|
|
ip6 = skb_header_pointer(skb, offset, sizeof(_ipv6h), &_ipv6h);
|
|
|
|
if (ip6 == NULL)
|
|
|
|
goto out;
|
|
|
|
|
2012-04-02 17:15:44 +00:00
|
|
|
ad->u.net->v6info.saddr = ip6->saddr;
|
|
|
|
ad->u.net->v6info.daddr = ip6->daddr;
|
2005-04-16 22:20:36 +00:00
|
|
|
ret = 0;
|
|
|
|
|
|
|
|
nexthdr = ip6->nexthdr;
|
|
|
|
offset += sizeof(_ipv6h);
|
2011-12-01 01:05:51 +00:00
|
|
|
offset = ipv6_skip_exthdr(skb, offset, &nexthdr, &frag_off);
|
2005-04-16 22:20:36 +00:00
|
|
|
if (offset < 0)
|
|
|
|
goto out;
|
|
|
|
|
2006-11-08 23:04:26 +00:00
|
|
|
if (proto)
|
|
|
|
*proto = nexthdr;
|
|
|
|
|
2005-04-16 22:20:36 +00:00
|
|
|
switch (nexthdr) {
|
|
|
|
case IPPROTO_TCP: {
|
2008-04-17 17:17:49 +00:00
|
|
|
struct tcphdr _tcph, *th;
|
2005-04-16 22:20:36 +00:00
|
|
|
|
|
|
|
th = skb_header_pointer(skb, offset, sizeof(_tcph), &_tcph);
|
|
|
|
if (th == NULL)
|
|
|
|
break;
|
|
|
|
|
2012-04-02 17:15:44 +00:00
|
|
|
ad->u.net->sport = th->source;
|
|
|
|
ad->u.net->dport = th->dest;
|
2005-04-16 22:20:36 +00:00
|
|
|
break;
|
|
|
|
}
|
|
|
|
|
|
|
|
case IPPROTO_UDP: {
|
|
|
|
struct udphdr _udph, *uh;
|
|
|
|
|
|
|
|
uh = skb_header_pointer(skb, offset, sizeof(_udph), &_udph);
|
|
|
|
if (uh == NULL)
|
|
|
|
break;
|
|
|
|
|
2012-04-02 17:15:44 +00:00
|
|
|
ad->u.net->sport = uh->source;
|
|
|
|
ad->u.net->dport = uh->dest;
|
2005-04-16 22:20:36 +00:00
|
|
|
break;
|
|
|
|
}
|
|
|
|
|
2006-11-14 00:09:01 +00:00
|
|
|
case IPPROTO_DCCP: {
|
|
|
|
struct dccp_hdr _dccph, *dh;
|
|
|
|
|
|
|
|
dh = skb_header_pointer(skb, offset, sizeof(_dccph), &_dccph);
|
|
|
|
if (dh == NULL)
|
|
|
|
break;
|
|
|
|
|
2012-04-02 17:15:44 +00:00
|
|
|
ad->u.net->sport = dh->dccph_sport;
|
|
|
|
ad->u.net->dport = dh->dccph_dport;
|
2006-11-14 00:09:01 +00:00
|
|
|
break;
|
2008-04-17 17:17:49 +00:00
|
|
|
}
|
2006-11-14 00:09:01 +00:00
|
|
|
|
2005-04-16 22:20:36 +00:00
|
|
|
/* includes fragments */
|
|
|
|
default:
|
|
|
|
break;
|
|
|
|
}
|
|
|
|
out:
|
|
|
|
return ret;
|
|
|
|
}
|
|
|
|
|
|
|
|
#endif /* IPV6 */
|
|
|
|
|
2009-07-14 16:14:09 +00:00
|
|
|
static int selinux_parse_skb(struct sk_buff *skb, struct common_audit_data *ad,
|
2008-07-27 11:31:07 +00:00
|
|
|
char **_addrp, int src, u8 *proto)
|
2005-04-16 22:20:36 +00:00
|
|
|
{
|
2008-07-27 11:31:07 +00:00
|
|
|
char *addrp;
|
|
|
|
int ret;
|
2005-04-16 22:20:36 +00:00
|
|
|
|
2012-04-02 17:15:44 +00:00
|
|
|
switch (ad->u.net->family) {
|
2005-04-16 22:20:36 +00:00
|
|
|
case PF_INET:
|
2006-11-08 23:04:26 +00:00
|
|
|
ret = selinux_parse_skb_ipv4(skb, ad, proto);
|
2008-07-27 11:31:07 +00:00
|
|
|
if (ret)
|
|
|
|
goto parse_error;
|
2012-04-02 17:15:44 +00:00
|
|
|
addrp = (char *)(src ? &ad->u.net->v4info.saddr :
|
|
|
|
&ad->u.net->v4info.daddr);
|
2008-07-27 11:31:07 +00:00
|
|
|
goto okay;
|
2005-04-16 22:20:36 +00:00
|
|
|
|
|
|
|
#if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
|
|
|
|
case PF_INET6:
|
2006-11-08 23:04:26 +00:00
|
|
|
ret = selinux_parse_skb_ipv6(skb, ad, proto);
|
2008-07-27 11:31:07 +00:00
|
|
|
if (ret)
|
|
|
|
goto parse_error;
|
2012-04-02 17:15:44 +00:00
|
|
|
addrp = (char *)(src ? &ad->u.net->v6info.saddr :
|
|
|
|
&ad->u.net->v6info.daddr);
|
2008-07-27 11:31:07 +00:00
|
|
|
goto okay;
|
2005-04-16 22:20:36 +00:00
|
|
|
#endif /* IPV6 */
|
|
|
|
default:
|
2008-07-27 11:31:07 +00:00
|
|
|
addrp = NULL;
|
|
|
|
goto okay;
|
2005-04-16 22:20:36 +00:00
|
|
|
}
|
|
|
|
|
2008-07-27 11:31:07 +00:00
|
|
|
parse_error:
|
|
|
|
printk(KERN_WARNING
|
|
|
|
"SELinux: failure in selinux_parse_skb(),"
|
|
|
|
" unable to parse packet\n");
|
2005-04-16 22:20:36 +00:00
|
|
|
return ret;
|
2008-07-27 11:31:07 +00:00
|
|
|
|
|
|
|
okay:
|
|
|
|
if (_addrp)
|
|
|
|
*_addrp = addrp;
|
|
|
|
return 0;
|
2005-04-16 22:20:36 +00:00
|
|
|
}
|
|
|
|
|
2007-03-01 19:35:22 +00:00
|
|
|
/**
|
2008-01-29 13:38:23 +00:00
|
|
|
* selinux_skb_peerlbl_sid - Determine the peer label of a packet
|
2007-03-01 19:35:22 +00:00
|
|
|
* @skb: the packet
|
2008-01-29 13:38:04 +00:00
|
|
|
* @family: protocol family
|
2008-01-29 13:38:23 +00:00
|
|
|
* @sid: the packet's peer label SID
|
2007-03-01 19:35:22 +00:00
|
|
|
*
|
|
|
|
* Description:
|
2008-01-29 13:38:23 +00:00
|
|
|
* Check the various different forms of network peer labeling and determine
|
|
|
|
* the peer label/SID for the packet; most of the magic actually occurs in
|
|
|
|
* the security server function security_net_peersid_cmp(). The function
|
|
|
|
* returns zero if the value in @sid is valid (although it may be SECSID_NULL)
|
|
|
|
* or -EACCES if @sid is invalid due to inconsistencies with the different
|
|
|
|
* peer labels.
|
2007-03-01 19:35:22 +00:00
|
|
|
*
|
|
|
|
*/
|
2008-01-29 13:38:23 +00:00
|
|
|
static int selinux_skb_peerlbl_sid(struct sk_buff *skb, u16 family, u32 *sid)
|
2007-03-01 19:35:22 +00:00
|
|
|
{
|
2008-01-29 13:51:16 +00:00
|
|
|
int err;
|
2007-03-01 19:35:22 +00:00
|
|
|
u32 xfrm_sid;
|
|
|
|
u32 nlbl_sid;
|
2008-01-29 13:38:23 +00:00
|
|
|
u32 nlbl_type;
|
2007-03-01 19:35:22 +00:00
|
|
|
|
2013-12-10 19:57:54 +00:00
|
|
|
err = selinux_xfrm_skb_sid(skb, &xfrm_sid);
|
2013-07-23 21:38:40 +00:00
|
|
|
if (unlikely(err))
|
|
|
|
return -EACCES;
|
|
|
|
err = selinux_netlbl_skbuff_getsid(skb, family, &nlbl_type, &nlbl_sid);
|
|
|
|
if (unlikely(err))
|
|
|
|
return -EACCES;
|
2008-01-29 13:38:23 +00:00
|
|
|
|
2008-01-29 13:51:16 +00:00
|
|
|
err = security_net_peersid_resolve(nlbl_sid, nlbl_type, xfrm_sid, sid);
|
|
|
|
if (unlikely(err)) {
|
|
|
|
printk(KERN_WARNING
|
|
|
|
"SELinux: failure in selinux_skb_peerlbl_sid(),"
|
|
|
|
" unable to determine packet's peer label\n");
|
2008-01-29 13:38:23 +00:00
|
|
|
return -EACCES;
|
2008-01-29 13:51:16 +00:00
|
|
|
}
|
2008-01-29 13:38:23 +00:00
|
|
|
|
|
|
|
return 0;
|
2007-03-01 19:35:22 +00:00
|
|
|
}
|
|
|
|
|
2013-12-04 21:10:51 +00:00
|
|
|
/**
|
|
|
|
* selinux_conn_sid - Determine the child socket label for a connection
|
|
|
|
* @sk_sid: the parent socket's SID
|
|
|
|
* @skb_sid: the packet's SID
|
|
|
|
* @conn_sid: the resulting connection SID
|
|
|
|
*
|
|
|
|
* If @skb_sid is valid then the user:role:type information from @sk_sid is
|
|
|
|
* combined with the MLS information from @skb_sid in order to create
|
|
|
|
* @conn_sid. If @skb_sid is not valid then then @conn_sid is simply a copy
|
|
|
|
* of @sk_sid. Returns zero on success, negative values on failure.
|
|
|
|
*
|
|
|
|
*/
|
|
|
|
static int selinux_conn_sid(u32 sk_sid, u32 skb_sid, u32 *conn_sid)
|
|
|
|
{
|
|
|
|
int err = 0;
|
|
|
|
|
|
|
|
if (skb_sid != SECSID_NULL)
|
|
|
|
err = security_sid_mls_copy(sk_sid, skb_sid, conn_sid);
|
|
|
|
else
|
|
|
|
*conn_sid = sk_sid;
|
|
|
|
|
|
|
|
return err;
|
|
|
|
}
|
|
|
|
|
2005-04-16 22:20:36 +00:00
|
|
|
/* socket security operations */
|
2010-04-22 18:46:18 +00:00
|
|
|
|
2011-03-02 05:32:34 +00:00
|
|
|
static int socket_sockcreate_sid(const struct task_security_struct *tsec,
|
|
|
|
u16 secclass, u32 *socksid)
|
2010-04-22 18:46:18 +00:00
|
|
|
{
|
2011-03-02 05:32:34 +00:00
|
|
|
if (tsec->sockcreate_sid > SECSID_NULL) {
|
|
|
|
*socksid = tsec->sockcreate_sid;
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
|
|
|
return security_transition_sid(tsec->sid, tsec->sid, secclass, NULL,
|
|
|
|
socksid);
|
2010-04-22 18:46:18 +00:00
|
|
|
}
|
|
|
|
|
2010-04-22 18:46:19 +00:00
|
|
|
static int sock_has_perm(struct task_struct *task, struct sock *sk, u32 perms)
|
2005-04-16 22:20:36 +00:00
|
|
|
{
|
2010-04-22 18:46:19 +00:00
|
|
|
struct sk_security_struct *sksec = sk->sk_security;
|
2009-07-14 16:14:09 +00:00
|
|
|
struct common_audit_data ad;
|
2012-04-02 17:15:44 +00:00
|
|
|
struct lsm_network_audit net = {0,};
|
2010-04-22 18:46:19 +00:00
|
|
|
u32 tsid = task_sid(task);
|
2005-04-16 22:20:36 +00:00
|
|
|
|
2010-04-22 18:46:19 +00:00
|
|
|
if (sksec->sid == SECINITSID_KERNEL)
|
|
|
|
return 0;
|
2005-04-16 22:20:36 +00:00
|
|
|
|
2012-04-04 19:01:43 +00:00
|
|
|
ad.type = LSM_AUDIT_DATA_NET;
|
2012-04-02 17:15:44 +00:00
|
|
|
ad.u.net = &net;
|
|
|
|
ad.u.net->sk = sk;
|
2005-04-16 22:20:36 +00:00
|
|
|
|
2010-04-22 18:46:19 +00:00
|
|
|
return avc_has_perm(tsid, sksec->sid, sksec->sclass, perms, &ad);
|
2005-04-16 22:20:36 +00:00
|
|
|
}
|
|
|
|
|
|
|
|
static int selinux_socket_create(int family, int type,
|
|
|
|
int protocol, int kern)
|
|
|
|
{
|
2010-04-22 18:46:19 +00:00
|
|
|
const struct task_security_struct *tsec = current_security();
|
2010-04-22 18:46:18 +00:00
|
|
|
u32 newsid;
|
2008-11-13 23:39:19 +00:00
|
|
|
u16 secclass;
|
2011-03-02 05:32:34 +00:00
|
|
|
int rc;
|
2005-04-16 22:20:36 +00:00
|
|
|
|
|
|
|
if (kern)
|
2010-04-22 18:46:18 +00:00
|
|
|
return 0;
|
2008-11-13 23:39:19 +00:00
|
|
|
|
|
|
|
secclass = socket_type_to_security_class(family, type, protocol);
|
2011-03-02 05:32:34 +00:00
|
|
|
rc = socket_sockcreate_sid(tsec, secclass, &newsid);
|
|
|
|
if (rc)
|
|
|
|
return rc;
|
|
|
|
|
2010-04-22 18:46:18 +00:00
|
|
|
return avc_has_perm(tsec->sid, newsid, secclass, SOCKET__CREATE, NULL);
|
2005-04-16 22:20:36 +00:00
|
|
|
}
|
|
|
|
|
2006-08-05 06:17:57 +00:00
|
|
|
static int selinux_socket_post_create(struct socket *sock, int family,
|
|
|
|
int type, int protocol, int kern)
|
2005-04-16 22:20:36 +00:00
|
|
|
{
|
2010-04-22 18:46:19 +00:00
|
|
|
const struct task_security_struct *tsec = current_security();
|
2010-04-22 18:46:18 +00:00
|
|
|
struct inode_security_struct *isec = SOCK_INODE(sock)->i_security;
|
2006-08-05 06:08:56 +00:00
|
|
|
struct sk_security_struct *sksec;
|
2008-11-13 23:39:19 +00:00
|
|
|
int err = 0;
|
|
|
|
|
2011-03-02 05:32:34 +00:00
|
|
|
isec->sclass = socket_type_to_security_class(family, type, protocol);
|
|
|
|
|
2008-11-13 23:39:19 +00:00
|
|
|
if (kern)
|
|
|
|
isec->sid = SECINITSID_KERNEL;
|
2011-03-02 05:32:34 +00:00
|
|
|
else {
|
|
|
|
err = socket_sockcreate_sid(tsec, isec->sclass, &(isec->sid));
|
|
|
|
if (err)
|
|
|
|
return err;
|
|
|
|
}
|
2008-11-13 23:39:19 +00:00
|
|
|
|
2005-04-16 22:20:36 +00:00
|
|
|
isec->initialized = 1;
|
|
|
|
|
2006-08-05 06:08:56 +00:00
|
|
|
if (sock->sk) {
|
|
|
|
sksec = sock->sk->sk_security;
|
|
|
|
sksec->sid = isec->sid;
|
2008-01-29 13:38:23 +00:00
|
|
|
sksec->sclass = isec->sclass;
|
2009-03-27 21:10:34 +00:00
|
|
|
err = selinux_netlbl_socket_post_create(sock->sk, family);
|
2006-08-05 06:08:56 +00:00
|
|
|
}
|
|
|
|
|
2006-08-05 06:17:57 +00:00
|
|
|
return err;
|
2005-04-16 22:20:36 +00:00
|
|
|
}
|
|
|
|
|
|
|
|
/* Range of port numbers used to automatically bind.
|
|
|
|
Need to determine whether we should perform a name_bind
|
|
|
|
permission check between the socket and the port number. */
|
|
|
|
|
|
|
|
static int selinux_socket_bind(struct socket *sock, struct sockaddr *address, int addrlen)
|
|
|
|
{
|
2010-04-22 18:46:19 +00:00
|
|
|
struct sock *sk = sock->sk;
|
2005-04-16 22:20:36 +00:00
|
|
|
u16 family;
|
|
|
|
int err;
|
|
|
|
|
2010-04-22 18:46:19 +00:00
|
|
|
err = sock_has_perm(current, sk, SOCKET__BIND);
|
2005-04-16 22:20:36 +00:00
|
|
|
if (err)
|
|
|
|
goto out;
|
|
|
|
|
|
|
|
/*
|
|
|
|
* If PF_INET or PF_INET6, check name_bind permission for the port.
|
[PATCH] SELinux - fix SCTP socket bug and general IP protocol handling
The following patch updates the way SELinux classifies and handles IP
based protocols.
Currently, IP sockets are classified by SELinux as being either TCP, UDP
or 'Raw', the latter being a default for IP socket that is not TCP or UDP.
The classification code is out of date and uses only the socket type
parameter to socket(2) to determine the class of IP socket. So, any
socket created with SOCK_STREAM will be classified by SELinux as TCP, and
SOCK_DGRAM as UDP. Also, other socket types such as SOCK_SEQPACKET and
SOCK_DCCP are currently ignored by SELinux, which classifies them as
generic sockets, which means they don't even get basic IP level checking.
This patch changes the SELinux IP socket classification logic, so that
only an IPPROTO_IP protocol value passed to socket(2) classify the socket
as TCP or UDP. The patch also drops the check for SOCK_RAW and converts
it into a default, so that socket types like SOCK_DCCP and SOCK_SEQPACKET
are classified as SECCLASS_RAWIP_SOCKET (instead of generic sockets).
Note that protocol-specific support for SCTP, DCCP etc. is not addressed
here, we're just getting these protocols checked at the IP layer.
This fixes a reported problem where SCTP sockets were being recognized as
generic SELinux sockets yet still being passed in one case to an IP level
check, which then fails for generic sockets.
It will also fix bugs where any SOCK_STREAM socket is classified as TCP or
any SOCK_DGRAM socket is classified as UDP.
This patch also unifies the way IP sockets classes are determined in
selinux_socket_bind(), so we use the already calculated value instead of
trying to recalculate it.
Signed-off-by: James Morris <jmorris@namei.org>
Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-09-30 18:24:34 +00:00
|
|
|
* Multiple address binding for SCTP is not supported yet: we just
|
|
|
|
* check the first address now.
|
2005-04-16 22:20:36 +00:00
|
|
|
*/
|
2010-04-22 18:46:19 +00:00
|
|
|
family = sk->sk_family;
|
2005-04-16 22:20:36 +00:00
|
|
|
if (family == PF_INET || family == PF_INET6) {
|
|
|
|
char *addrp;
|
2010-04-22 18:46:19 +00:00
|
|
|
struct sk_security_struct *sksec = sk->sk_security;
|
2009-07-14 16:14:09 +00:00
|
|
|
struct common_audit_data ad;
|
2012-04-02 17:15:44 +00:00
|
|
|
struct lsm_network_audit net = {0,};
|
2005-04-16 22:20:36 +00:00
|
|
|
struct sockaddr_in *addr4 = NULL;
|
|
|
|
struct sockaddr_in6 *addr6 = NULL;
|
|
|
|
unsigned short snum;
|
2008-06-11 15:39:58 +00:00
|
|
|
u32 sid, node_perm;
|
2005-04-16 22:20:36 +00:00
|
|
|
|
|
|
|
if (family == PF_INET) {
|
|
|
|
addr4 = (struct sockaddr_in *)address;
|
|
|
|
snum = ntohs(addr4->sin_port);
|
|
|
|
addrp = (char *)&addr4->sin_addr.s_addr;
|
|
|
|
} else {
|
|
|
|
addr6 = (struct sockaddr_in6 *)address;
|
|
|
|
snum = ntohs(addr6->sin6_port);
|
|
|
|
addrp = (char *)&addr6->sin6_addr.s6_addr;
|
|
|
|
}
|
|
|
|
|
2007-10-11 00:30:46 +00:00
|
|
|
if (snum) {
|
|
|
|
int low, high;
|
|
|
|
|
2013-09-28 21:10:59 +00:00
|
|
|
inet_get_local_port_range(sock_net(sk), &low, &high);
|
2007-10-11 00:30:46 +00:00
|
|
|
|
|
|
|
if (snum < max(PROT_SOCK, low) || snum > high) {
|
2008-04-10 14:48:14 +00:00
|
|
|
err = sel_netport_sid(sk->sk_protocol,
|
|
|
|
snum, &sid);
|
2007-10-11 00:30:46 +00:00
|
|
|
if (err)
|
|
|
|
goto out;
|
2012-04-04 19:01:43 +00:00
|
|
|
ad.type = LSM_AUDIT_DATA_NET;
|
2012-04-02 17:15:44 +00:00
|
|
|
ad.u.net = &net;
|
|
|
|
ad.u.net->sport = htons(snum);
|
|
|
|
ad.u.net->family = family;
|
2010-04-22 18:46:19 +00:00
|
|
|
err = avc_has_perm(sksec->sid, sid,
|
|
|
|
sksec->sclass,
|
2007-10-11 00:30:46 +00:00
|
|
|
SOCKET__NAME_BIND, &ad);
|
|
|
|
if (err)
|
|
|
|
goto out;
|
|
|
|
}
|
2005-04-16 22:20:36 +00:00
|
|
|
}
|
2008-04-17 17:17:49 +00:00
|
|
|
|
2010-04-22 18:46:19 +00:00
|
|
|
switch (sksec->sclass) {
|
[PATCH] SELinux - fix SCTP socket bug and general IP protocol handling
The following patch updates the way SELinux classifies and handles IP
based protocols.
Currently, IP sockets are classified by SELinux as being either TCP, UDP
or 'Raw', the latter being a default for IP socket that is not TCP or UDP.
The classification code is out of date and uses only the socket type
parameter to socket(2) to determine the class of IP socket. So, any
socket created with SOCK_STREAM will be classified by SELinux as TCP, and
SOCK_DGRAM as UDP. Also, other socket types such as SOCK_SEQPACKET and
SOCK_DCCP are currently ignored by SELinux, which classifies them as
generic sockets, which means they don't even get basic IP level checking.
This patch changes the SELinux IP socket classification logic, so that
only an IPPROTO_IP protocol value passed to socket(2) classify the socket
as TCP or UDP. The patch also drops the check for SOCK_RAW and converts
it into a default, so that socket types like SOCK_DCCP and SOCK_SEQPACKET
are classified as SECCLASS_RAWIP_SOCKET (instead of generic sockets).
Note that protocol-specific support for SCTP, DCCP etc. is not addressed
here, we're just getting these protocols checked at the IP layer.
This fixes a reported problem where SCTP sockets were being recognized as
generic SELinux sockets yet still being passed in one case to an IP level
check, which then fails for generic sockets.
It will also fix bugs where any SOCK_STREAM socket is classified as TCP or
any SOCK_DGRAM socket is classified as UDP.
This patch also unifies the way IP sockets classes are determined in
selinux_socket_bind(), so we use the already calculated value instead of
trying to recalculate it.
Signed-off-by: James Morris <jmorris@namei.org>
Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-09-30 18:24:34 +00:00
|
|
|
case SECCLASS_TCP_SOCKET:
|
2005-04-16 22:20:36 +00:00
|
|
|
node_perm = TCP_SOCKET__NODE_BIND;
|
|
|
|
break;
|
2008-04-17 17:17:49 +00:00
|
|
|
|
[PATCH] SELinux - fix SCTP socket bug and general IP protocol handling
The following patch updates the way SELinux classifies and handles IP
based protocols.
Currently, IP sockets are classified by SELinux as being either TCP, UDP
or 'Raw', the latter being a default for IP socket that is not TCP or UDP.
The classification code is out of date and uses only the socket type
parameter to socket(2) to determine the class of IP socket. So, any
socket created with SOCK_STREAM will be classified by SELinux as TCP, and
SOCK_DGRAM as UDP. Also, other socket types such as SOCK_SEQPACKET and
SOCK_DCCP are currently ignored by SELinux, which classifies them as
generic sockets, which means they don't even get basic IP level checking.
This patch changes the SELinux IP socket classification logic, so that
only an IPPROTO_IP protocol value passed to socket(2) classify the socket
as TCP or UDP. The patch also drops the check for SOCK_RAW and converts
it into a default, so that socket types like SOCK_DCCP and SOCK_SEQPACKET
are classified as SECCLASS_RAWIP_SOCKET (instead of generic sockets).
Note that protocol-specific support for SCTP, DCCP etc. is not addressed
here, we're just getting these protocols checked at the IP layer.
This fixes a reported problem where SCTP sockets were being recognized as
generic SELinux sockets yet still being passed in one case to an IP level
check, which then fails for generic sockets.
It will also fix bugs where any SOCK_STREAM socket is classified as TCP or
any SOCK_DGRAM socket is classified as UDP.
This patch also unifies the way IP sockets classes are determined in
selinux_socket_bind(), so we use the already calculated value instead of
trying to recalculate it.
Signed-off-by: James Morris <jmorris@namei.org>
Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-09-30 18:24:34 +00:00
|
|
|
case SECCLASS_UDP_SOCKET:
|
2005-04-16 22:20:36 +00:00
|
|
|
node_perm = UDP_SOCKET__NODE_BIND;
|
|
|
|
break;
|
2006-11-14 00:09:01 +00:00
|
|
|
|
|
|
|
case SECCLASS_DCCP_SOCKET:
|
|
|
|
node_perm = DCCP_SOCKET__NODE_BIND;
|
|
|
|
break;
|
|
|
|
|
2005-04-16 22:20:36 +00:00
|
|
|
default:
|
|
|
|
node_perm = RAWIP_SOCKET__NODE_BIND;
|
|
|
|
break;
|
|
|
|
}
|
2008-04-17 17:17:49 +00:00
|
|
|
|
2008-01-29 13:38:13 +00:00
|
|
|
err = sel_netnode_sid(addrp, family, &sid);
|
2005-04-16 22:20:36 +00:00
|
|
|
if (err)
|
|
|
|
goto out;
|
2008-04-17 17:17:49 +00:00
|
|
|
|
2012-04-04 19:01:43 +00:00
|
|
|
ad.type = LSM_AUDIT_DATA_NET;
|
2012-04-02 17:15:44 +00:00
|
|
|
ad.u.net = &net;
|
|
|
|
ad.u.net->sport = htons(snum);
|
|
|
|
ad.u.net->family = family;
|
2005-04-16 22:20:36 +00:00
|
|
|
|
|
|
|
if (family == PF_INET)
|
2012-04-02 17:15:44 +00:00
|
|
|
ad.u.net->v4info.saddr = addr4->sin_addr.s_addr;
|
2005-04-16 22:20:36 +00:00
|
|
|
else
|
2012-04-02 17:15:44 +00:00
|
|
|
ad.u.net->v6info.saddr = addr6->sin6_addr;
|
2005-04-16 22:20:36 +00:00
|
|
|
|
2010-04-22 18:46:19 +00:00
|
|
|
err = avc_has_perm(sksec->sid, sid,
|
|
|
|
sksec->sclass, node_perm, &ad);
|
2005-04-16 22:20:36 +00:00
|
|
|
if (err)
|
|
|
|
goto out;
|
|
|
|
}
|
|
|
|
out:
|
|
|
|
return err;
|
|
|
|
}
|
|
|
|
|
|
|
|
static int selinux_socket_connect(struct socket *sock, struct sockaddr *address, int addrlen)
|
|
|
|
{
|
2008-10-10 14:16:33 +00:00
|
|
|
struct sock *sk = sock->sk;
|
2010-04-22 18:46:19 +00:00
|
|
|
struct sk_security_struct *sksec = sk->sk_security;
|
2005-04-16 22:20:36 +00:00
|
|
|
int err;
|
|
|
|
|
2010-04-22 18:46:19 +00:00
|
|
|
err = sock_has_perm(current, sk, SOCKET__CONNECT);
|
2005-04-16 22:20:36 +00:00
|
|
|
if (err)
|
|
|
|
return err;
|
|
|
|
|
|
|
|
/*
|
2006-11-14 00:09:01 +00:00
|
|
|
* If a TCP or DCCP socket, check name_connect permission for the port.
|
2005-04-16 22:20:36 +00:00
|
|
|
*/
|
2010-04-22 18:46:19 +00:00
|
|
|
if (sksec->sclass == SECCLASS_TCP_SOCKET ||
|
|
|
|
sksec->sclass == SECCLASS_DCCP_SOCKET) {
|
2009-07-14 16:14:09 +00:00
|
|
|
struct common_audit_data ad;
|
2012-04-02 17:15:44 +00:00
|
|
|
struct lsm_network_audit net = {0,};
|
2005-04-16 22:20:36 +00:00
|
|
|
struct sockaddr_in *addr4 = NULL;
|
|
|
|
struct sockaddr_in6 *addr6 = NULL;
|
|
|
|
unsigned short snum;
|
2006-11-14 00:09:01 +00:00
|
|
|
u32 sid, perm;
|
2005-04-16 22:20:36 +00:00
|
|
|
|
|
|
|
if (sk->sk_family == PF_INET) {
|
|
|
|
addr4 = (struct sockaddr_in *)address;
|
2005-07-29 04:16:21 +00:00
|
|
|
if (addrlen < sizeof(struct sockaddr_in))
|
2005-04-16 22:20:36 +00:00
|
|
|
return -EINVAL;
|
|
|
|
snum = ntohs(addr4->sin_port);
|
|
|
|
} else {
|
|
|
|
addr6 = (struct sockaddr_in6 *)address;
|
2005-07-29 04:16:21 +00:00
|
|
|
if (addrlen < SIN6_LEN_RFC2133)
|
2005-04-16 22:20:36 +00:00
|
|
|
return -EINVAL;
|
|
|
|
snum = ntohs(addr6->sin6_port);
|
|
|
|
}
|
|
|
|
|
2008-04-10 14:48:14 +00:00
|
|
|
err = sel_netport_sid(sk->sk_protocol, snum, &sid);
|
2005-04-16 22:20:36 +00:00
|
|
|
if (err)
|
|
|
|
goto out;
|
|
|
|
|
2010-04-22 18:46:19 +00:00
|
|
|
perm = (sksec->sclass == SECCLASS_TCP_SOCKET) ?
|
2006-11-14 00:09:01 +00:00
|
|
|
TCP_SOCKET__NAME_CONNECT : DCCP_SOCKET__NAME_CONNECT;
|
|
|
|
|
2012-04-04 19:01:43 +00:00
|
|
|
ad.type = LSM_AUDIT_DATA_NET;
|
2012-04-02 17:15:44 +00:00
|
|
|
ad.u.net = &net;
|
|
|
|
ad.u.net->dport = htons(snum);
|
|
|
|
ad.u.net->family = sk->sk_family;
|
2010-04-22 18:46:19 +00:00
|
|
|
err = avc_has_perm(sksec->sid, sid, sksec->sclass, perm, &ad);
|
2005-04-16 22:20:36 +00:00
|
|
|
if (err)
|
|
|
|
goto out;
|
|
|
|
}
|
|
|
|
|
2008-10-10 14:16:33 +00:00
|
|
|
err = selinux_netlbl_socket_connect(sk, address);
|
|
|
|
|
2005-04-16 22:20:36 +00:00
|
|
|
out:
|
|
|
|
return err;
|
|
|
|
}
|
|
|
|
|
|
|
|
static int selinux_socket_listen(struct socket *sock, int backlog)
|
|
|
|
{
|
2010-04-22 18:46:19 +00:00
|
|
|
return sock_has_perm(current, sock->sk, SOCKET__LISTEN);
|
2005-04-16 22:20:36 +00:00
|
|
|
}
|
|
|
|
|
|
|
|
static int selinux_socket_accept(struct socket *sock, struct socket *newsock)
|
|
|
|
{
|
|
|
|
int err;
|
|
|
|
struct inode_security_struct *isec;
|
|
|
|
struct inode_security_struct *newisec;
|
|
|
|
|
2010-04-22 18:46:19 +00:00
|
|
|
err = sock_has_perm(current, sock->sk, SOCKET__ACCEPT);
|
2005-04-16 22:20:36 +00:00
|
|
|
if (err)
|
|
|
|
return err;
|
|
|
|
|
|
|
|
newisec = SOCK_INODE(newsock)->i_security;
|
|
|
|
|
|
|
|
isec = SOCK_INODE(sock)->i_security;
|
|
|
|
newisec->sclass = isec->sclass;
|
|
|
|
newisec->sid = isec->sid;
|
|
|
|
newisec->initialized = 1;
|
|
|
|
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
|
|
|
static int selinux_socket_sendmsg(struct socket *sock, struct msghdr *msg,
|
2008-04-17 17:17:49 +00:00
|
|
|
int size)
|
2005-04-16 22:20:36 +00:00
|
|
|
{
|
2010-04-22 18:46:19 +00:00
|
|
|
return sock_has_perm(current, sock->sk, SOCKET__WRITE);
|
2005-04-16 22:20:36 +00:00
|
|
|
}
|
|
|
|
|
|
|
|
static int selinux_socket_recvmsg(struct socket *sock, struct msghdr *msg,
|
|
|
|
int size, int flags)
|
|
|
|
{
|
2010-04-22 18:46:19 +00:00
|
|
|
return sock_has_perm(current, sock->sk, SOCKET__READ);
|
2005-04-16 22:20:36 +00:00
|
|
|
}
|
|
|
|
|
|
|
|
static int selinux_socket_getsockname(struct socket *sock)
|
|
|
|
{
|
2010-04-22 18:46:19 +00:00
|
|
|
return sock_has_perm(current, sock->sk, SOCKET__GETATTR);
|
2005-04-16 22:20:36 +00:00
|
|
|
}
|
|
|
|
|
|
|
|
static int selinux_socket_getpeername(struct socket *sock)
|
|
|
|
{
|
2010-04-22 18:46:19 +00:00
|
|
|
return sock_has_perm(current, sock->sk, SOCKET__GETATTR);
|
2005-04-16 22:20:36 +00:00
|
|
|
}
|
|
|
|
|
2008-04-17 17:17:49 +00:00
|
|
|
static int selinux_socket_setsockopt(struct socket *sock, int level, int optname)
|
2005-04-16 22:20:36 +00:00
|
|
|
{
|
2006-10-30 23:22:15 +00:00
|
|
|
int err;
|
|
|
|
|
2010-04-22 18:46:19 +00:00
|
|
|
err = sock_has_perm(current, sock->sk, SOCKET__SETOPT);
|
2006-10-30 23:22:15 +00:00
|
|
|
if (err)
|
|
|
|
return err;
|
|
|
|
|
|
|
|
return selinux_netlbl_socket_setsockopt(sock, level, optname);
|
2005-04-16 22:20:36 +00:00
|
|
|
}
|
|
|
|
|
|
|
|
static int selinux_socket_getsockopt(struct socket *sock, int level,
|
|
|
|
int optname)
|
|
|
|
{
|
2010-04-22 18:46:19 +00:00
|
|
|
return sock_has_perm(current, sock->sk, SOCKET__GETOPT);
|
2005-04-16 22:20:36 +00:00
|
|
|
}
|
|
|
|
|
|
|
|
static int selinux_socket_shutdown(struct socket *sock, int how)
|
|
|
|
{
|
2010-04-22 18:46:19 +00:00
|
|
|
return sock_has_perm(current, sock->sk, SOCKET__SHUTDOWN);
|
2005-04-16 22:20:36 +00:00
|
|
|
}
|
|
|
|
|
2011-01-05 23:38:53 +00:00
|
|
|
static int selinux_socket_unix_stream_connect(struct sock *sock,
|
|
|
|
struct sock *other,
|
2005-04-16 22:20:36 +00:00
|
|
|
struct sock *newsk)
|
|
|
|
{
|
2011-01-05 23:38:53 +00:00
|
|
|
struct sk_security_struct *sksec_sock = sock->sk_security;
|
|
|
|
struct sk_security_struct *sksec_other = other->sk_security;
|
2010-04-22 18:46:18 +00:00
|
|
|
struct sk_security_struct *sksec_new = newsk->sk_security;
|
2009-07-14 16:14:09 +00:00
|
|
|
struct common_audit_data ad;
|
2012-04-02 17:15:44 +00:00
|
|
|
struct lsm_network_audit net = {0,};
|
2005-04-16 22:20:36 +00:00
|
|
|
int err;
|
|
|
|
|
2012-04-04 19:01:43 +00:00
|
|
|
ad.type = LSM_AUDIT_DATA_NET;
|
2012-04-02 17:15:44 +00:00
|
|
|
ad.u.net = &net;
|
|
|
|
ad.u.net->sk = other;
|
2005-04-16 22:20:36 +00:00
|
|
|
|
2010-04-22 18:46:18 +00:00
|
|
|
err = avc_has_perm(sksec_sock->sid, sksec_other->sid,
|
|
|
|
sksec_other->sclass,
|
2005-04-16 22:20:36 +00:00
|
|
|
UNIX_STREAM_SOCKET__CONNECTTO, &ad);
|
|
|
|
if (err)
|
|
|
|
return err;
|
|
|
|
|
|
|
|
/* server child socket */
|
2010-04-22 18:46:18 +00:00
|
|
|
sksec_new->peer_sid = sksec_sock->sid;
|
|
|
|
err = security_sid_mls_copy(sksec_other->sid, sksec_sock->sid,
|
|
|
|
&sksec_new->sid);
|
|
|
|
if (err)
|
|
|
|
return err;
|
2006-07-25 06:32:50 +00:00
|
|
|
|
2010-04-22 18:46:18 +00:00
|
|
|
/* connecting socket */
|
|
|
|
sksec_sock->peer_sid = sksec_new->sid;
|
|
|
|
|
|
|
|
return 0;
|
2005-04-16 22:20:36 +00:00
|
|
|
}
|
|
|
|
|
|
|
|
static int selinux_socket_unix_may_send(struct socket *sock,
|
|
|
|
struct socket *other)
|
|
|
|
{
|
2010-04-22 18:46:19 +00:00
|
|
|
struct sk_security_struct *ssec = sock->sk->sk_security;
|
|
|
|
struct sk_security_struct *osec = other->sk->sk_security;
|
2009-07-14 16:14:09 +00:00
|
|
|
struct common_audit_data ad;
|
2012-04-02 17:15:44 +00:00
|
|
|
struct lsm_network_audit net = {0,};
|
2005-04-16 22:20:36 +00:00
|
|
|
|
2012-04-04 19:01:43 +00:00
|
|
|
ad.type = LSM_AUDIT_DATA_NET;
|
2012-04-02 17:15:44 +00:00
|
|
|
ad.u.net = &net;
|
|
|
|
ad.u.net->sk = other->sk;
|
2005-04-16 22:20:36 +00:00
|
|
|
|
2010-04-22 18:46:19 +00:00
|
|
|
return avc_has_perm(ssec->sid, osec->sid, osec->sclass, SOCKET__SENDTO,
|
|
|
|
&ad);
|
2005-04-16 22:20:36 +00:00
|
|
|
}
|
|
|
|
|
2008-01-29 13:49:27 +00:00
|
|
|
static int selinux_inet_sys_rcv_skb(int ifindex, char *addrp, u16 family,
|
|
|
|
u32 peer_sid,
|
2009-07-14 16:14:09 +00:00
|
|
|
struct common_audit_data *ad)
|
2008-01-29 13:49:27 +00:00
|
|
|
{
|
|
|
|
int err;
|
|
|
|
u32 if_sid;
|
|
|
|
u32 node_sid;
|
|
|
|
|
|
|
|
err = sel_netif_sid(ifindex, &if_sid);
|
|
|
|
if (err)
|
|
|
|
return err;
|
|
|
|
err = avc_has_perm(peer_sid, if_sid,
|
|
|
|
SECCLASS_NETIF, NETIF__INGRESS, ad);
|
|
|
|
if (err)
|
|
|
|
return err;
|
|
|
|
|
|
|
|
err = sel_netnode_sid(addrp, family, &node_sid);
|
|
|
|
if (err)
|
|
|
|
return err;
|
|
|
|
return avc_has_perm(peer_sid, node_sid,
|
|
|
|
SECCLASS_NODE, NODE__RECVFROM, ad);
|
|
|
|
}
|
|
|
|
|
2008-01-29 13:38:23 +00:00
|
|
|
static int selinux_sock_rcv_skb_compat(struct sock *sk, struct sk_buff *skb,
|
2008-10-10 14:16:30 +00:00
|
|
|
u16 family)
|
2008-01-29 13:38:23 +00:00
|
|
|
{
|
2008-12-31 17:54:11 +00:00
|
|
|
int err = 0;
|
2008-01-29 13:38:23 +00:00
|
|
|
struct sk_security_struct *sksec = sk->sk_security;
|
|
|
|
u32 sk_sid = sksec->sid;
|
2009-07-14 16:14:09 +00:00
|
|
|
struct common_audit_data ad;
|
2012-04-02 17:15:44 +00:00
|
|
|
struct lsm_network_audit net = {0,};
|
2008-10-10 14:16:30 +00:00
|
|
|
char *addrp;
|
|
|
|
|
2012-04-04 19:01:43 +00:00
|
|
|
ad.type = LSM_AUDIT_DATA_NET;
|
2012-04-02 17:15:44 +00:00
|
|
|
ad.u.net = &net;
|
|
|
|
ad.u.net->netif = skb->skb_iif;
|
|
|
|
ad.u.net->family = family;
|
2008-10-10 14:16:30 +00:00
|
|
|
err = selinux_parse_skb(skb, &ad, &addrp, 1, NULL);
|
|
|
|
if (err)
|
|
|
|
return err;
|
2005-04-16 22:20:36 +00:00
|
|
|
|
2009-03-27 21:10:41 +00:00
|
|
|
if (selinux_secmark_enabled()) {
|
2008-01-29 13:38:23 +00:00
|
|
|
err = avc_has_perm(sk_sid, skb->secmark, SECCLASS_PACKET,
|
2008-10-10 14:16:30 +00:00
|
|
|
PACKET__RECV, &ad);
|
2009-03-27 21:10:41 +00:00
|
|
|
if (err)
|
|
|
|
return err;
|
|
|
|
}
|
2008-01-29 13:38:23 +00:00
|
|
|
|
2011-02-23 11:55:21 +00:00
|
|
|
err = selinux_netlbl_sock_rcv_skb(sksec, skb, family, &ad);
|
|
|
|
if (err)
|
|
|
|
return err;
|
|
|
|
err = selinux_xfrm_sock_rcv_skb(sksec->sid, skb, &ad);
|
[LSM-IPSec]: Per-packet access control.
This patch series implements per packet access control via the
extension of the Linux Security Modules (LSM) interface by hooks in
the XFRM and pfkey subsystems that leverage IPSec security
associations to label packets. Extensions to the SELinux LSM are
included that leverage the patch for this purpose.
This patch implements the changes necessary to the SELinux LSM to
create, deallocate, and use security contexts for policies
(xfrm_policy) and security associations (xfrm_state) that enable
control of a socket's ability to send and receive packets.
Patch purpose:
The patch is designed to enable the SELinux LSM to implement access
control on individual packets based on the strongly authenticated
IPSec security association. Such access controls augment the existing
ones in SELinux based on network interface and IP address. The former
are very coarse-grained, and the latter can be spoofed. By using
IPSec, the SELinux can control access to remote hosts based on
cryptographic keys generated using the IPSec mechanism. This enables
access control on a per-machine basis or per-application if the remote
machine is running the same mechanism and trusted to enforce the
access control policy.
Patch design approach:
The patch's main function is to authorize a socket's access to a IPSec
policy based on their security contexts. Since the communication is
implemented by a security association, the patch ensures that the
security association's negotiated and used have the same security
context. The patch enables allocation and deallocation of such
security contexts for policies and security associations. It also
enables copying of the security context when policies are cloned.
Lastly, the patch ensures that packets that are sent without using a
IPSec security assocation with a security context are allowed to be
sent in that manner.
A presentation available at
www.selinux-symposium.org/2005/presentations/session2/2-3-jaeger.pdf
from the SELinux symposium describes the overall approach.
Patch implementation details:
The function which authorizes a socket to perform a requested
operation (send/receive) on a IPSec policy (xfrm_policy) is
selinux_xfrm_policy_lookup. The Netfilter and rcv_skb hooks ensure
that if a IPSec SA with a securit y association has not been used,
then the socket is allowed to send or receive the packet,
respectively.
The patch implements SELinux function for allocating security contexts
when policies (xfrm_policy) are created via the pfkey or xfrm_user
interfaces via selinux_xfrm_policy_alloc. When a security association
is built, SELinux allocates the security context designated by the
XFRM subsystem which is based on that of the authorized policy via
selinux_xfrm_state_alloc.
When a xfrm_policy is cloned, the security context of that policy, if
any, is copied to the clone via selinux_xfrm_policy_clone.
When a xfrm_policy or xfrm_state is freed, its security context, if
any is also freed at selinux_xfrm_policy_free or
selinux_xfrm_state_free.
Testing:
The SELinux authorization function is tested using ipsec-tools. We
created policies and security associations with particular security
contexts and added SELinux access control policy entries to verify the
authorization decision. We also made sure that packets for which no
security context was supplied (which either did or did not use
security associations) were authorized using an unlabelled context.
Signed-off-by: Trent Jaeger <tjaeger@cse.psu.edu>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
2005-12-14 07:12:40 +00:00
|
|
|
|
[SECMARK]: Add new packet controls to SELinux
Add new per-packet access controls to SELinux, replacing the old
packet controls.
Packets are labeled with the iptables SECMARK and CONNSECMARK targets,
then security policy for the packets is enforced with these controls.
To allow for a smooth transition to the new controls, the old code is
still present, but not active by default. To restore previous
behavior, the old controls may be activated at runtime by writing a
'1' to /selinux/compat_net, and also via the kernel boot parameter
selinux_compat_net. Switching between the network control models
requires the security load_policy permission. The old controls will
probably eventually be removed and any continued use is discouraged.
With this patch, the new secmark controls for SElinux are disabled by
default, so existing behavior is entirely preserved, and the user is
not affected at all.
It also provides a config option to enable the secmark controls by
default (which can always be overridden at boot and runtime). It is
also noted in the kconfig help that the user will need updated
userspace if enabling secmark controls for SELinux and that they'll
probably need the SECMARK and CONNMARK targets, and conntrack protocol
helpers, although such decisions are beyond the scope of kernel
configuration.
Signed-off-by: James Morris <jmorris@namei.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-06-09 07:33:33 +00:00
|
|
|
return err;
|
|
|
|
}
|
|
|
|
|
|
|
|
static int selinux_socket_sock_rcv_skb(struct sock *sk, struct sk_buff *skb)
|
|
|
|
{
|
2008-01-29 13:38:23 +00:00
|
|
|
int err;
|
2006-07-25 06:32:50 +00:00
|
|
|
struct sk_security_struct *sksec = sk->sk_security;
|
2008-01-29 13:38:23 +00:00
|
|
|
u16 family = sk->sk_family;
|
|
|
|
u32 sk_sid = sksec->sid;
|
2009-07-14 16:14:09 +00:00
|
|
|
struct common_audit_data ad;
|
2012-04-02 17:15:44 +00:00
|
|
|
struct lsm_network_audit net = {0,};
|
2008-01-29 13:38:23 +00:00
|
|
|
char *addrp;
|
2008-10-10 14:16:30 +00:00
|
|
|
u8 secmark_active;
|
|
|
|
u8 peerlbl_active;
|
[SECMARK]: Add new packet controls to SELinux
Add new per-packet access controls to SELinux, replacing the old
packet controls.
Packets are labeled with the iptables SECMARK and CONNSECMARK targets,
then security policy for the packets is enforced with these controls.
To allow for a smooth transition to the new controls, the old code is
still present, but not active by default. To restore previous
behavior, the old controls may be activated at runtime by writing a
'1' to /selinux/compat_net, and also via the kernel boot parameter
selinux_compat_net. Switching between the network control models
requires the security load_policy permission. The old controls will
probably eventually be removed and any continued use is discouraged.
With this patch, the new secmark controls for SElinux are disabled by
default, so existing behavior is entirely preserved, and the user is
not affected at all.
It also provides a config option to enable the secmark controls by
default (which can always be overridden at boot and runtime). It is
also noted in the kconfig help that the user will need updated
userspace if enabling secmark controls for SELinux and that they'll
probably need the SECMARK and CONNMARK targets, and conntrack protocol
helpers, although such decisions are beyond the scope of kernel
configuration.
Signed-off-by: James Morris <jmorris@namei.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-06-09 07:33:33 +00:00
|
|
|
|
|
|
|
if (family != PF_INET && family != PF_INET6)
|
2008-01-29 13:38:23 +00:00
|
|
|
return 0;
|
[SECMARK]: Add new packet controls to SELinux
Add new per-packet access controls to SELinux, replacing the old
packet controls.
Packets are labeled with the iptables SECMARK and CONNSECMARK targets,
then security policy for the packets is enforced with these controls.
To allow for a smooth transition to the new controls, the old code is
still present, but not active by default. To restore previous
behavior, the old controls may be activated at runtime by writing a
'1' to /selinux/compat_net, and also via the kernel boot parameter
selinux_compat_net. Switching between the network control models
requires the security load_policy permission. The old controls will
probably eventually be removed and any continued use is discouraged.
With this patch, the new secmark controls for SElinux are disabled by
default, so existing behavior is entirely preserved, and the user is
not affected at all.
It also provides a config option to enable the secmark controls by
default (which can always be overridden at boot and runtime). It is
also noted in the kconfig help that the user will need updated
userspace if enabling secmark controls for SELinux and that they'll
probably need the SECMARK and CONNMARK targets, and conntrack protocol
helpers, although such decisions are beyond the scope of kernel
configuration.
Signed-off-by: James Morris <jmorris@namei.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-06-09 07:33:33 +00:00
|
|
|
|
|
|
|
/* Handle mapped IPv4 packets arriving via IPv6 sockets */
|
2006-12-04 22:00:55 +00:00
|
|
|
if (family == PF_INET6 && skb->protocol == htons(ETH_P_IP))
|
[SECMARK]: Add new packet controls to SELinux
Add new per-packet access controls to SELinux, replacing the old
packet controls.
Packets are labeled with the iptables SECMARK and CONNSECMARK targets,
then security policy for the packets is enforced with these controls.
To allow for a smooth transition to the new controls, the old code is
still present, but not active by default. To restore previous
behavior, the old controls may be activated at runtime by writing a
'1' to /selinux/compat_net, and also via the kernel boot parameter
selinux_compat_net. Switching between the network control models
requires the security load_policy permission. The old controls will
probably eventually be removed and any continued use is discouraged.
With this patch, the new secmark controls for SElinux are disabled by
default, so existing behavior is entirely preserved, and the user is
not affected at all.
It also provides a config option to enable the secmark controls by
default (which can always be overridden at boot and runtime). It is
also noted in the kconfig help that the user will need updated
userspace if enabling secmark controls for SELinux and that they'll
probably need the SECMARK and CONNMARK targets, and conntrack protocol
helpers, although such decisions are beyond the scope of kernel
configuration.
Signed-off-by: James Morris <jmorris@namei.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-06-09 07:33:33 +00:00
|
|
|
family = PF_INET;
|
|
|
|
|
2008-10-10 14:16:30 +00:00
|
|
|
/* If any sort of compatibility mode is enabled then handoff processing
|
|
|
|
* to the selinux_sock_rcv_skb_compat() function to deal with the
|
|
|
|
* special handling. We do this in an attempt to keep this function
|
|
|
|
* as fast and as clean as possible. */
|
2009-03-27 21:10:41 +00:00
|
|
|
if (!selinux_policycap_netpeer)
|
2008-10-10 14:16:30 +00:00
|
|
|
return selinux_sock_rcv_skb_compat(sk, skb, family);
|
|
|
|
|
|
|
|
secmark_active = selinux_secmark_enabled();
|
2013-05-03 13:05:39 +00:00
|
|
|
peerlbl_active = selinux_peerlbl_enabled();
|
2008-10-10 14:16:30 +00:00
|
|
|
if (!secmark_active && !peerlbl_active)
|
|
|
|
return 0;
|
|
|
|
|
2012-04-04 19:01:43 +00:00
|
|
|
ad.type = LSM_AUDIT_DATA_NET;
|
2012-04-02 17:15:44 +00:00
|
|
|
ad.u.net = &net;
|
|
|
|
ad.u.net->netif = skb->skb_iif;
|
|
|
|
ad.u.net->family = family;
|
2008-01-29 13:38:13 +00:00
|
|
|
err = selinux_parse_skb(skb, &ad, &addrp, 1, NULL);
|
[SECMARK]: Add new packet controls to SELinux
Add new per-packet access controls to SELinux, replacing the old
packet controls.
Packets are labeled with the iptables SECMARK and CONNSECMARK targets,
then security policy for the packets is enforced with these controls.
To allow for a smooth transition to the new controls, the old code is
still present, but not active by default. To restore previous
behavior, the old controls may be activated at runtime by writing a
'1' to /selinux/compat_net, and also via the kernel boot parameter
selinux_compat_net. Switching between the network control models
requires the security load_policy permission. The old controls will
probably eventually be removed and any continued use is discouraged.
With this patch, the new secmark controls for SElinux are disabled by
default, so existing behavior is entirely preserved, and the user is
not affected at all.
It also provides a config option to enable the secmark controls by
default (which can always be overridden at boot and runtime). It is
also noted in the kconfig help that the user will need updated
userspace if enabling secmark controls for SELinux and that they'll
probably need the SECMARK and CONNMARK targets, and conntrack protocol
helpers, although such decisions are beyond the scope of kernel
configuration.
Signed-off-by: James Morris <jmorris@namei.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-06-09 07:33:33 +00:00
|
|
|
if (err)
|
2008-01-29 13:38:23 +00:00
|
|
|
return err;
|
[SECMARK]: Add new packet controls to SELinux
Add new per-packet access controls to SELinux, replacing the old
packet controls.
Packets are labeled with the iptables SECMARK and CONNSECMARK targets,
then security policy for the packets is enforced with these controls.
To allow for a smooth transition to the new controls, the old code is
still present, but not active by default. To restore previous
behavior, the old controls may be activated at runtime by writing a
'1' to /selinux/compat_net, and also via the kernel boot parameter
selinux_compat_net. Switching between the network control models
requires the security load_policy permission. The old controls will
probably eventually be removed and any continued use is discouraged.
With this patch, the new secmark controls for SElinux are disabled by
default, so existing behavior is entirely preserved, and the user is
not affected at all.
It also provides a config option to enable the secmark controls by
default (which can always be overridden at boot and runtime). It is
also noted in the kconfig help that the user will need updated
userspace if enabling secmark controls for SELinux and that they'll
probably need the SECMARK and CONNMARK targets, and conntrack protocol
helpers, although such decisions are beyond the scope of kernel
configuration.
Signed-off-by: James Morris <jmorris@namei.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-06-09 07:33:33 +00:00
|
|
|
|
2008-10-10 14:16:30 +00:00
|
|
|
if (peerlbl_active) {
|
2008-01-29 13:43:36 +00:00
|
|
|
u32 peer_sid;
|
|
|
|
|
|
|
|
err = selinux_skb_peerlbl_sid(skb, family, &peer_sid);
|
2008-01-29 13:49:27 +00:00
|
|
|
if (err)
|
|
|
|
return err;
|
2009-11-20 23:35:04 +00:00
|
|
|
err = selinux_inet_sys_rcv_skb(skb->skb_iif, addrp, family,
|
2008-01-29 13:49:27 +00:00
|
|
|
peer_sid, &ad);
|
2008-10-10 14:16:31 +00:00
|
|
|
if (err) {
|
|
|
|
selinux_netlbl_err(skb, err, 0);
|
2008-01-29 13:43:36 +00:00
|
|
|
return err;
|
2008-10-10 14:16:31 +00:00
|
|
|
}
|
2008-01-29 13:43:36 +00:00
|
|
|
err = avc_has_perm(sk_sid, peer_sid, SECCLASS_PEER,
|
|
|
|
PEER__RECV, &ad);
|
2013-12-23 22:45:01 +00:00
|
|
|
if (err) {
|
2008-10-10 14:16:31 +00:00
|
|
|
selinux_netlbl_err(skb, err, 0);
|
2013-12-23 22:45:01 +00:00
|
|
|
return err;
|
|
|
|
}
|
2008-01-29 13:43:36 +00:00
|
|
|
}
|
|
|
|
|
2008-10-10 14:16:30 +00:00
|
|
|
if (secmark_active) {
|
2008-01-29 13:49:27 +00:00
|
|
|
err = avc_has_perm(sk_sid, skb->secmark, SECCLASS_PACKET,
|
|
|
|
PACKET__RECV, &ad);
|
|
|
|
if (err)
|
|
|
|
return err;
|
|
|
|
}
|
|
|
|
|
2008-01-29 13:43:36 +00:00
|
|
|
return err;
|
2005-04-16 22:20:36 +00:00
|
|
|
}
|
|
|
|
|
[SECURITY]: TCP/UDP getpeersec
This patch implements an application of the LSM-IPSec networking
controls whereby an application can determine the label of the
security association its TCP or UDP sockets are currently connected to
via getsockopt and the auxiliary data mechanism of recvmsg.
Patch purpose:
This patch enables a security-aware application to retrieve the
security context of an IPSec security association a particular TCP or
UDP socket is using. The application can then use this security
context to determine the security context for processing on behalf of
the peer at the other end of this connection. In the case of UDP, the
security context is for each individual packet. An example
application is the inetd daemon, which could be modified to start
daemons running at security contexts dependent on the remote client.
Patch design approach:
- Design for TCP
The patch enables the SELinux LSM to set the peer security context for
a socket based on the security context of the IPSec security
association. The application may retrieve this context using
getsockopt. When called, the kernel determines if the socket is a
connected (TCP_ESTABLISHED) TCP socket and, if so, uses the dst_entry
cache on the socket to retrieve the security associations. If a
security association has a security context, the context string is
returned, as for UNIX domain sockets.
- Design for UDP
Unlike TCP, UDP is connectionless. This requires a somewhat different
API to retrieve the peer security context. With TCP, the peer
security context stays the same throughout the connection, thus it can
be retrieved at any time between when the connection is established
and when it is torn down. With UDP, each read/write can have
different peer and thus the security context might change every time.
As a result the security context retrieval must be done TOGETHER with
the packet retrieval.
The solution is to build upon the existing Unix domain socket API for
retrieving user credentials. Linux offers the API for obtaining user
credentials via ancillary messages (i.e., out of band/control messages
that are bundled together with a normal message).
Patch implementation details:
- Implementation for TCP
The security context can be retrieved by applications using getsockopt
with the existing SO_PEERSEC flag. As an example (ignoring error
checking):
getsockopt(sockfd, SOL_SOCKET, SO_PEERSEC, optbuf, &optlen);
printf("Socket peer context is: %s\n", optbuf);
The SELinux function, selinux_socket_getpeersec, is extended to check
for labeled security associations for connected (TCP_ESTABLISHED ==
sk->sk_state) TCP sockets only. If so, the socket has a dst_cache of
struct dst_entry values that may refer to security associations. If
these have security associations with security contexts, the security
context is returned.
getsockopt returns a buffer that contains a security context string or
the buffer is unmodified.
- Implementation for UDP
To retrieve the security context, the application first indicates to
the kernel such desire by setting the IP_PASSSEC option via
getsockopt. Then the application retrieves the security context using
the auxiliary data mechanism.
An example server application for UDP should look like this:
toggle = 1;
toggle_len = sizeof(toggle);
setsockopt(sockfd, SOL_IP, IP_PASSSEC, &toggle, &toggle_len);
recvmsg(sockfd, &msg_hdr, 0);
if (msg_hdr.msg_controllen > sizeof(struct cmsghdr)) {
cmsg_hdr = CMSG_FIRSTHDR(&msg_hdr);
if (cmsg_hdr->cmsg_len <= CMSG_LEN(sizeof(scontext)) &&
cmsg_hdr->cmsg_level == SOL_IP &&
cmsg_hdr->cmsg_type == SCM_SECURITY) {
memcpy(&scontext, CMSG_DATA(cmsg_hdr), sizeof(scontext));
}
}
ip_setsockopt is enhanced with a new socket option IP_PASSSEC to allow
a server socket to receive security context of the peer. A new
ancillary message type SCM_SECURITY.
When the packet is received we get the security context from the
sec_path pointer which is contained in the sk_buff, and copy it to the
ancillary message space. An additional LSM hook,
selinux_socket_getpeersec_udp, is defined to retrieve the security
context from the SELinux space. The existing function,
selinux_socket_getpeersec does not suit our purpose, because the
security context is copied directly to user space, rather than to
kernel space.
Testing:
We have tested the patch by setting up TCP and UDP connections between
applications on two machines using the IPSec policies that result in
labeled security associations being built. For TCP, we can then
extract the peer security context using getsockopt on either end. For
UDP, the receiving end can retrieve the security context using the
auxiliary data mechanism of recvmsg.
Signed-off-by: Catherine Zhang <cxzhang@watson.ibm.com>
Acked-by: James Morris <jmorris@namei.org>
Acked-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-03-21 06:41:23 +00:00
|
|
|
static int selinux_socket_getpeersec_stream(struct socket *sock, char __user *optval,
|
|
|
|
int __user *optlen, unsigned len)
|
2005-04-16 22:20:36 +00:00
|
|
|
{
|
|
|
|
int err = 0;
|
|
|
|
char *scontext;
|
|
|
|
u32 scontext_len;
|
2010-04-22 18:46:19 +00:00
|
|
|
struct sk_security_struct *sksec = sock->sk->sk_security;
|
2006-11-17 22:38:54 +00:00
|
|
|
u32 peer_sid = SECSID_NULL;
|
2005-04-16 22:20:36 +00:00
|
|
|
|
2010-04-22 18:46:19 +00:00
|
|
|
if (sksec->sclass == SECCLASS_UNIX_STREAM_SOCKET ||
|
|
|
|
sksec->sclass == SECCLASS_TCP_SOCKET)
|
2010-04-07 19:08:46 +00:00
|
|
|
peer_sid = sksec->peer_sid;
|
2010-04-22 18:46:19 +00:00
|
|
|
if (peer_sid == SECSID_NULL)
|
|
|
|
return -ENOPROTOOPT;
|
2005-04-16 22:20:36 +00:00
|
|
|
|
[SECURITY]: TCP/UDP getpeersec
This patch implements an application of the LSM-IPSec networking
controls whereby an application can determine the label of the
security association its TCP or UDP sockets are currently connected to
via getsockopt and the auxiliary data mechanism of recvmsg.
Patch purpose:
This patch enables a security-aware application to retrieve the
security context of an IPSec security association a particular TCP or
UDP socket is using. The application can then use this security
context to determine the security context for processing on behalf of
the peer at the other end of this connection. In the case of UDP, the
security context is for each individual packet. An example
application is the inetd daemon, which could be modified to start
daemons running at security contexts dependent on the remote client.
Patch design approach:
- Design for TCP
The patch enables the SELinux LSM to set the peer security context for
a socket based on the security context of the IPSec security
association. The application may retrieve this context using
getsockopt. When called, the kernel determines if the socket is a
connected (TCP_ESTABLISHED) TCP socket and, if so, uses the dst_entry
cache on the socket to retrieve the security associations. If a
security association has a security context, the context string is
returned, as for UNIX domain sockets.
- Design for UDP
Unlike TCP, UDP is connectionless. This requires a somewhat different
API to retrieve the peer security context. With TCP, the peer
security context stays the same throughout the connection, thus it can
be retrieved at any time between when the connection is established
and when it is torn down. With UDP, each read/write can have
different peer and thus the security context might change every time.
As a result the security context retrieval must be done TOGETHER with
the packet retrieval.
The solution is to build upon the existing Unix domain socket API for
retrieving user credentials. Linux offers the API for obtaining user
credentials via ancillary messages (i.e., out of band/control messages
that are bundled together with a normal message).
Patch implementation details:
- Implementation for TCP
The security context can be retrieved by applications using getsockopt
with the existing SO_PEERSEC flag. As an example (ignoring error
checking):
getsockopt(sockfd, SOL_SOCKET, SO_PEERSEC, optbuf, &optlen);
printf("Socket peer context is: %s\n", optbuf);
The SELinux function, selinux_socket_getpeersec, is extended to check
for labeled security associations for connected (TCP_ESTABLISHED ==
sk->sk_state) TCP sockets only. If so, the socket has a dst_cache of
struct dst_entry values that may refer to security associations. If
these have security associations with security contexts, the security
context is returned.
getsockopt returns a buffer that contains a security context string or
the buffer is unmodified.
- Implementation for UDP
To retrieve the security context, the application first indicates to
the kernel such desire by setting the IP_PASSSEC option via
getsockopt. Then the application retrieves the security context using
the auxiliary data mechanism.
An example server application for UDP should look like this:
toggle = 1;
toggle_len = sizeof(toggle);
setsockopt(sockfd, SOL_IP, IP_PASSSEC, &toggle, &toggle_len);
recvmsg(sockfd, &msg_hdr, 0);
if (msg_hdr.msg_controllen > sizeof(struct cmsghdr)) {
cmsg_hdr = CMSG_FIRSTHDR(&msg_hdr);
if (cmsg_hdr->cmsg_len <= CMSG_LEN(sizeof(scontext)) &&
cmsg_hdr->cmsg_level == SOL_IP &&
cmsg_hdr->cmsg_type == SCM_SECURITY) {
memcpy(&scontext, CMSG_DATA(cmsg_hdr), sizeof(scontext));
}
}
ip_setsockopt is enhanced with a new socket option IP_PASSSEC to allow
a server socket to receive security context of the peer. A new
ancillary message type SCM_SECURITY.
When the packet is received we get the security context from the
sec_path pointer which is contained in the sk_buff, and copy it to the
ancillary message space. An additional LSM hook,
selinux_socket_getpeersec_udp, is defined to retrieve the security
context from the SELinux space. The existing function,
selinux_socket_getpeersec does not suit our purpose, because the
security context is copied directly to user space, rather than to
kernel space.
Testing:
We have tested the patch by setting up TCP and UDP connections between
applications on two machines using the IPSec policies that result in
labeled security associations being built. For TCP, we can then
extract the peer security context using getsockopt on either end. For
UDP, the receiving end can retrieve the security context using the
auxiliary data mechanism of recvmsg.
Signed-off-by: Catherine Zhang <cxzhang@watson.ibm.com>
Acked-by: James Morris <jmorris@namei.org>
Acked-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-03-21 06:41:23 +00:00
|
|
|
err = security_sid_to_context(peer_sid, &scontext, &scontext_len);
|
2005-04-16 22:20:36 +00:00
|
|
|
if (err)
|
2010-04-22 18:46:19 +00:00
|
|
|
return err;
|
2005-04-16 22:20:36 +00:00
|
|
|
|
|
|
|
if (scontext_len > len) {
|
|
|
|
err = -ERANGE;
|
|
|
|
goto out_len;
|
|
|
|
}
|
|
|
|
|
|
|
|
if (copy_to_user(optval, scontext, scontext_len))
|
|
|
|
err = -EFAULT;
|
|
|
|
|
|
|
|
out_len:
|
|
|
|
if (put_user(scontext_len, optlen))
|
|
|
|
err = -EFAULT;
|
|
|
|
kfree(scontext);
|
|
|
|
return err;
|
|
|
|
}
|
|
|
|
|
2006-08-02 21:12:06 +00:00
|
|
|
static int selinux_socket_getpeersec_dgram(struct socket *sock, struct sk_buff *skb, u32 *secid)
|
[SECURITY]: TCP/UDP getpeersec
This patch implements an application of the LSM-IPSec networking
controls whereby an application can determine the label of the
security association its TCP or UDP sockets are currently connected to
via getsockopt and the auxiliary data mechanism of recvmsg.
Patch purpose:
This patch enables a security-aware application to retrieve the
security context of an IPSec security association a particular TCP or
UDP socket is using. The application can then use this security
context to determine the security context for processing on behalf of
the peer at the other end of this connection. In the case of UDP, the
security context is for each individual packet. An example
application is the inetd daemon, which could be modified to start
daemons running at security contexts dependent on the remote client.
Patch design approach:
- Design for TCP
The patch enables the SELinux LSM to set the peer security context for
a socket based on the security context of the IPSec security
association. The application may retrieve this context using
getsockopt. When called, the kernel determines if the socket is a
connected (TCP_ESTABLISHED) TCP socket and, if so, uses the dst_entry
cache on the socket to retrieve the security associations. If a
security association has a security context, the context string is
returned, as for UNIX domain sockets.
- Design for UDP
Unlike TCP, UDP is connectionless. This requires a somewhat different
API to retrieve the peer security context. With TCP, the peer
security context stays the same throughout the connection, thus it can
be retrieved at any time between when the connection is established
and when it is torn down. With UDP, each read/write can have
different peer and thus the security context might change every time.
As a result the security context retrieval must be done TOGETHER with
the packet retrieval.
The solution is to build upon the existing Unix domain socket API for
retrieving user credentials. Linux offers the API for obtaining user
credentials via ancillary messages (i.e., out of band/control messages
that are bundled together with a normal message).
Patch implementation details:
- Implementation for TCP
The security context can be retrieved by applications using getsockopt
with the existing SO_PEERSEC flag. As an example (ignoring error
checking):
getsockopt(sockfd, SOL_SOCKET, SO_PEERSEC, optbuf, &optlen);
printf("Socket peer context is: %s\n", optbuf);
The SELinux function, selinux_socket_getpeersec, is extended to check
for labeled security associations for connected (TCP_ESTABLISHED ==
sk->sk_state) TCP sockets only. If so, the socket has a dst_cache of
struct dst_entry values that may refer to security associations. If
these have security associations with security contexts, the security
context is returned.
getsockopt returns a buffer that contains a security context string or
the buffer is unmodified.
- Implementation for UDP
To retrieve the security context, the application first indicates to
the kernel such desire by setting the IP_PASSSEC option via
getsockopt. Then the application retrieves the security context using
the auxiliary data mechanism.
An example server application for UDP should look like this:
toggle = 1;
toggle_len = sizeof(toggle);
setsockopt(sockfd, SOL_IP, IP_PASSSEC, &toggle, &toggle_len);
recvmsg(sockfd, &msg_hdr, 0);
if (msg_hdr.msg_controllen > sizeof(struct cmsghdr)) {
cmsg_hdr = CMSG_FIRSTHDR(&msg_hdr);
if (cmsg_hdr->cmsg_len <= CMSG_LEN(sizeof(scontext)) &&
cmsg_hdr->cmsg_level == SOL_IP &&
cmsg_hdr->cmsg_type == SCM_SECURITY) {
memcpy(&scontext, CMSG_DATA(cmsg_hdr), sizeof(scontext));
}
}
ip_setsockopt is enhanced with a new socket option IP_PASSSEC to allow
a server socket to receive security context of the peer. A new
ancillary message type SCM_SECURITY.
When the packet is received we get the security context from the
sec_path pointer which is contained in the sk_buff, and copy it to the
ancillary message space. An additional LSM hook,
selinux_socket_getpeersec_udp, is defined to retrieve the security
context from the SELinux space. The existing function,
selinux_socket_getpeersec does not suit our purpose, because the
security context is copied directly to user space, rather than to
kernel space.
Testing:
We have tested the patch by setting up TCP and UDP connections between
applications on two machines using the IPSec policies that result in
labeled security associations being built. For TCP, we can then
extract the peer security context using getsockopt on either end. For
UDP, the receiving end can retrieve the security context using the
auxiliary data mechanism of recvmsg.
Signed-off-by: Catherine Zhang <cxzhang@watson.ibm.com>
Acked-by: James Morris <jmorris@namei.org>
Acked-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-03-21 06:41:23 +00:00
|
|
|
{
|
2006-08-02 21:12:06 +00:00
|
|
|
u32 peer_secid = SECSID_NULL;
|
2008-01-29 13:38:04 +00:00
|
|
|
u16 family;
|
[AF_UNIX]: Datagram getpeersec
This patch implements an API whereby an application can determine the
label of its peer's Unix datagram sockets via the auxiliary data mechanism of
recvmsg.
Patch purpose:
This patch enables a security-aware application to retrieve the
security context of the peer of a Unix datagram socket. The application
can then use this security context to determine the security context for
processing on behalf of the peer who sent the packet.
Patch design and implementation:
The design and implementation is very similar to the UDP case for INET
sockets. Basically we build upon the existing Unix domain socket API for
retrieving user credentials. Linux offers the API for obtaining user
credentials via ancillary messages (i.e., out of band/control messages
that are bundled together with a normal message). To retrieve the security
context, the application first indicates to the kernel such desire by
setting the SO_PASSSEC option via getsockopt. Then the application
retrieves the security context using the auxiliary data mechanism.
An example server application for Unix datagram socket should look like this:
toggle = 1;
toggle_len = sizeof(toggle);
setsockopt(sockfd, SOL_SOCKET, SO_PASSSEC, &toggle, &toggle_len);
recvmsg(sockfd, &msg_hdr, 0);
if (msg_hdr.msg_controllen > sizeof(struct cmsghdr)) {
cmsg_hdr = CMSG_FIRSTHDR(&msg_hdr);
if (cmsg_hdr->cmsg_len <= CMSG_LEN(sizeof(scontext)) &&
cmsg_hdr->cmsg_level == SOL_SOCKET &&
cmsg_hdr->cmsg_type == SCM_SECURITY) {
memcpy(&scontext, CMSG_DATA(cmsg_hdr), sizeof(scontext));
}
}
sock_setsockopt is enhanced with a new socket option SOCK_PASSSEC to allow
a server socket to receive security context of the peer.
Testing:
We have tested the patch by setting up Unix datagram client and server
applications. We verified that the server can retrieve the security context
using the auxiliary data mechanism of recvmsg.
Signed-off-by: Catherine Zhang <cxzhang@watson.ibm.com>
Acked-by: Acked-by: James Morris <jmorris@namei.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-06-29 19:27:47 +00:00
|
|
|
|
2008-10-10 14:16:29 +00:00
|
|
|
if (skb && skb->protocol == htons(ETH_P_IP))
|
|
|
|
family = PF_INET;
|
|
|
|
else if (skb && skb->protocol == htons(ETH_P_IPV6))
|
|
|
|
family = PF_INET6;
|
|
|
|
else if (sock)
|
2008-01-29 13:38:04 +00:00
|
|
|
family = sock->sk->sk_family;
|
|
|
|
else
|
|
|
|
goto out;
|
|
|
|
|
|
|
|
if (sock && family == PF_UNIX)
|
2008-03-01 19:52:30 +00:00
|
|
|
selinux_inode_getsecid(SOCK_INODE(sock), &peer_secid);
|
2006-11-17 22:38:54 +00:00
|
|
|
else if (skb)
|
2008-01-29 13:38:23 +00:00
|
|
|
selinux_skb_peerlbl_sid(skb, family, &peer_secid);
|
[SECURITY]: TCP/UDP getpeersec
This patch implements an application of the LSM-IPSec networking
controls whereby an application can determine the label of the
security association its TCP or UDP sockets are currently connected to
via getsockopt and the auxiliary data mechanism of recvmsg.
Patch purpose:
This patch enables a security-aware application to retrieve the
security context of an IPSec security association a particular TCP or
UDP socket is using. The application can then use this security
context to determine the security context for processing on behalf of
the peer at the other end of this connection. In the case of UDP, the
security context is for each individual packet. An example
application is the inetd daemon, which could be modified to start
daemons running at security contexts dependent on the remote client.
Patch design approach:
- Design for TCP
The patch enables the SELinux LSM to set the peer security context for
a socket based on the security context of the IPSec security
association. The application may retrieve this context using
getsockopt. When called, the kernel determines if the socket is a
connected (TCP_ESTABLISHED) TCP socket and, if so, uses the dst_entry
cache on the socket to retrieve the security associations. If a
security association has a security context, the context string is
returned, as for UNIX domain sockets.
- Design for UDP
Unlike TCP, UDP is connectionless. This requires a somewhat different
API to retrieve the peer security context. With TCP, the peer
security context stays the same throughout the connection, thus it can
be retrieved at any time between when the connection is established
and when it is torn down. With UDP, each read/write can have
different peer and thus the security context might change every time.
As a result the security context retrieval must be done TOGETHER with
the packet retrieval.
The solution is to build upon the existing Unix domain socket API for
retrieving user credentials. Linux offers the API for obtaining user
credentials via ancillary messages (i.e., out of band/control messages
that are bundled together with a normal message).
Patch implementation details:
- Implementation for TCP
The security context can be retrieved by applications using getsockopt
with the existing SO_PEERSEC flag. As an example (ignoring error
checking):
getsockopt(sockfd, SOL_SOCKET, SO_PEERSEC, optbuf, &optlen);
printf("Socket peer context is: %s\n", optbuf);
The SELinux function, selinux_socket_getpeersec, is extended to check
for labeled security associations for connected (TCP_ESTABLISHED ==
sk->sk_state) TCP sockets only. If so, the socket has a dst_cache of
struct dst_entry values that may refer to security associations. If
these have security associations with security contexts, the security
context is returned.
getsockopt returns a buffer that contains a security context string or
the buffer is unmodified.
- Implementation for UDP
To retrieve the security context, the application first indicates to
the kernel such desire by setting the IP_PASSSEC option via
getsockopt. Then the application retrieves the security context using
the auxiliary data mechanism.
An example server application for UDP should look like this:
toggle = 1;
toggle_len = sizeof(toggle);
setsockopt(sockfd, SOL_IP, IP_PASSSEC, &toggle, &toggle_len);
recvmsg(sockfd, &msg_hdr, 0);
if (msg_hdr.msg_controllen > sizeof(struct cmsghdr)) {
cmsg_hdr = CMSG_FIRSTHDR(&msg_hdr);
if (cmsg_hdr->cmsg_len <= CMSG_LEN(sizeof(scontext)) &&
cmsg_hdr->cmsg_level == SOL_IP &&
cmsg_hdr->cmsg_type == SCM_SECURITY) {
memcpy(&scontext, CMSG_DATA(cmsg_hdr), sizeof(scontext));
}
}
ip_setsockopt is enhanced with a new socket option IP_PASSSEC to allow
a server socket to receive security context of the peer. A new
ancillary message type SCM_SECURITY.
When the packet is received we get the security context from the
sec_path pointer which is contained in the sk_buff, and copy it to the
ancillary message space. An additional LSM hook,
selinux_socket_getpeersec_udp, is defined to retrieve the security
context from the SELinux space. The existing function,
selinux_socket_getpeersec does not suit our purpose, because the
security context is copied directly to user space, rather than to
kernel space.
Testing:
We have tested the patch by setting up TCP and UDP connections between
applications on two machines using the IPSec policies that result in
labeled security associations being built. For TCP, we can then
extract the peer security context using getsockopt on either end. For
UDP, the receiving end can retrieve the security context using the
auxiliary data mechanism of recvmsg.
Signed-off-by: Catherine Zhang <cxzhang@watson.ibm.com>
Acked-by: James Morris <jmorris@namei.org>
Acked-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-03-21 06:41:23 +00:00
|
|
|
|
2008-01-29 13:38:04 +00:00
|
|
|
out:
|
2006-08-02 21:12:06 +00:00
|
|
|
*secid = peer_secid;
|
2008-01-29 13:38:04 +00:00
|
|
|
if (peer_secid == SECSID_NULL)
|
|
|
|
return -EINVAL;
|
|
|
|
return 0;
|
[SECURITY]: TCP/UDP getpeersec
This patch implements an application of the LSM-IPSec networking
controls whereby an application can determine the label of the
security association its TCP or UDP sockets are currently connected to
via getsockopt and the auxiliary data mechanism of recvmsg.
Patch purpose:
This patch enables a security-aware application to retrieve the
security context of an IPSec security association a particular TCP or
UDP socket is using. The application can then use this security
context to determine the security context for processing on behalf of
the peer at the other end of this connection. In the case of UDP, the
security context is for each individual packet. An example
application is the inetd daemon, which could be modified to start
daemons running at security contexts dependent on the remote client.
Patch design approach:
- Design for TCP
The patch enables the SELinux LSM to set the peer security context for
a socket based on the security context of the IPSec security
association. The application may retrieve this context using
getsockopt. When called, the kernel determines if the socket is a
connected (TCP_ESTABLISHED) TCP socket and, if so, uses the dst_entry
cache on the socket to retrieve the security associations. If a
security association has a security context, the context string is
returned, as for UNIX domain sockets.
- Design for UDP
Unlike TCP, UDP is connectionless. This requires a somewhat different
API to retrieve the peer security context. With TCP, the peer
security context stays the same throughout the connection, thus it can
be retrieved at any time between when the connection is established
and when it is torn down. With UDP, each read/write can have
different peer and thus the security context might change every time.
As a result the security context retrieval must be done TOGETHER with
the packet retrieval.
The solution is to build upon the existing Unix domain socket API for
retrieving user credentials. Linux offers the API for obtaining user
credentials via ancillary messages (i.e., out of band/control messages
that are bundled together with a normal message).
Patch implementation details:
- Implementation for TCP
The security context can be retrieved by applications using getsockopt
with the existing SO_PEERSEC flag. As an example (ignoring error
checking):
getsockopt(sockfd, SOL_SOCKET, SO_PEERSEC, optbuf, &optlen);
printf("Socket peer context is: %s\n", optbuf);
The SELinux function, selinux_socket_getpeersec, is extended to check
for labeled security associations for connected (TCP_ESTABLISHED ==
sk->sk_state) TCP sockets only. If so, the socket has a dst_cache of
struct dst_entry values that may refer to security associations. If
these have security associations with security contexts, the security
context is returned.
getsockopt returns a buffer that contains a security context string or
the buffer is unmodified.
- Implementation for UDP
To retrieve the security context, the application first indicates to
the kernel such desire by setting the IP_PASSSEC option via
getsockopt. Then the application retrieves the security context using
the auxiliary data mechanism.
An example server application for UDP should look like this:
toggle = 1;
toggle_len = sizeof(toggle);
setsockopt(sockfd, SOL_IP, IP_PASSSEC, &toggle, &toggle_len);
recvmsg(sockfd, &msg_hdr, 0);
if (msg_hdr.msg_controllen > sizeof(struct cmsghdr)) {
cmsg_hdr = CMSG_FIRSTHDR(&msg_hdr);
if (cmsg_hdr->cmsg_len <= CMSG_LEN(sizeof(scontext)) &&
cmsg_hdr->cmsg_level == SOL_IP &&
cmsg_hdr->cmsg_type == SCM_SECURITY) {
memcpy(&scontext, CMSG_DATA(cmsg_hdr), sizeof(scontext));
}
}
ip_setsockopt is enhanced with a new socket option IP_PASSSEC to allow
a server socket to receive security context of the peer. A new
ancillary message type SCM_SECURITY.
When the packet is received we get the security context from the
sec_path pointer which is contained in the sk_buff, and copy it to the
ancillary message space. An additional LSM hook,
selinux_socket_getpeersec_udp, is defined to retrieve the security
context from the SELinux space. The existing function,
selinux_socket_getpeersec does not suit our purpose, because the
security context is copied directly to user space, rather than to
kernel space.
Testing:
We have tested the patch by setting up TCP and UDP connections between
applications on two machines using the IPSec policies that result in
labeled security associations being built. For TCP, we can then
extract the peer security context using getsockopt on either end. For
UDP, the receiving end can retrieve the security context using the
auxiliary data mechanism of recvmsg.
Signed-off-by: Catherine Zhang <cxzhang@watson.ibm.com>
Acked-by: James Morris <jmorris@namei.org>
Acked-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-03-21 06:41:23 +00:00
|
|
|
}
|
|
|
|
|
2005-10-21 07:20:43 +00:00
|
|
|
static int selinux_sk_alloc_security(struct sock *sk, int family, gfp_t priority)
|
2005-04-16 22:20:36 +00:00
|
|
|
{
|
2010-04-22 18:46:18 +00:00
|
|
|
struct sk_security_struct *sksec;
|
|
|
|
|
|
|
|
sksec = kzalloc(sizeof(*sksec), priority);
|
|
|
|
if (!sksec)
|
|
|
|
return -ENOMEM;
|
|
|
|
|
|
|
|
sksec->peer_sid = SECINITSID_UNLABELED;
|
|
|
|
sksec->sid = SECINITSID_UNLABELED;
|
|
|
|
selinux_netlbl_sk_security_reset(sksec);
|
|
|
|
sk->sk_security = sksec;
|
|
|
|
|
|
|
|
return 0;
|
2005-04-16 22:20:36 +00:00
|
|
|
}
|
|
|
|
|
|
|
|
static void selinux_sk_free_security(struct sock *sk)
|
|
|
|
{
|
2010-04-22 18:46:18 +00:00
|
|
|
struct sk_security_struct *sksec = sk->sk_security;
|
|
|
|
|
|
|
|
sk->sk_security = NULL;
|
|
|
|
selinux_netlbl_sk_security_free(sksec);
|
|
|
|
kfree(sksec);
|
2005-04-16 22:20:36 +00:00
|
|
|
}
|
|
|
|
|
2006-08-05 06:08:56 +00:00
|
|
|
static void selinux_sk_clone_security(const struct sock *sk, struct sock *newsk)
|
[LSM-IPSec]: Per-packet access control.
This patch series implements per packet access control via the
extension of the Linux Security Modules (LSM) interface by hooks in
the XFRM and pfkey subsystems that leverage IPSec security
associations to label packets. Extensions to the SELinux LSM are
included that leverage the patch for this purpose.
This patch implements the changes necessary to the SELinux LSM to
create, deallocate, and use security contexts for policies
(xfrm_policy) and security associations (xfrm_state) that enable
control of a socket's ability to send and receive packets.
Patch purpose:
The patch is designed to enable the SELinux LSM to implement access
control on individual packets based on the strongly authenticated
IPSec security association. Such access controls augment the existing
ones in SELinux based on network interface and IP address. The former
are very coarse-grained, and the latter can be spoofed. By using
IPSec, the SELinux can control access to remote hosts based on
cryptographic keys generated using the IPSec mechanism. This enables
access control on a per-machine basis or per-application if the remote
machine is running the same mechanism and trusted to enforce the
access control policy.
Patch design approach:
The patch's main function is to authorize a socket's access to a IPSec
policy based on their security contexts. Since the communication is
implemented by a security association, the patch ensures that the
security association's negotiated and used have the same security
context. The patch enables allocation and deallocation of such
security contexts for policies and security associations. It also
enables copying of the security context when policies are cloned.
Lastly, the patch ensures that packets that are sent without using a
IPSec security assocation with a security context are allowed to be
sent in that manner.
A presentation available at
www.selinux-symposium.org/2005/presentations/session2/2-3-jaeger.pdf
from the SELinux symposium describes the overall approach.
Patch implementation details:
The function which authorizes a socket to perform a requested
operation (send/receive) on a IPSec policy (xfrm_policy) is
selinux_xfrm_policy_lookup. The Netfilter and rcv_skb hooks ensure
that if a IPSec SA with a securit y association has not been used,
then the socket is allowed to send or receive the packet,
respectively.
The patch implements SELinux function for allocating security contexts
when policies (xfrm_policy) are created via the pfkey or xfrm_user
interfaces via selinux_xfrm_policy_alloc. When a security association
is built, SELinux allocates the security context designated by the
XFRM subsystem which is based on that of the authorized policy via
selinux_xfrm_state_alloc.
When a xfrm_policy is cloned, the security context of that policy, if
any, is copied to the clone via selinux_xfrm_policy_clone.
When a xfrm_policy or xfrm_state is freed, its security context, if
any is also freed at selinux_xfrm_policy_free or
selinux_xfrm_state_free.
Testing:
The SELinux authorization function is tested using ipsec-tools. We
created policies and security associations with particular security
contexts and added SELinux access control policy entries to verify the
authorization decision. We also made sure that packets for which no
security context was supplied (which either did or did not use
security associations) were authorized using an unlabelled context.
Signed-off-by: Trent Jaeger <tjaeger@cse.psu.edu>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
2005-12-14 07:12:40 +00:00
|
|
|
{
|
2010-04-07 19:08:46 +00:00
|
|
|
struct sk_security_struct *sksec = sk->sk_security;
|
|
|
|
struct sk_security_struct *newsksec = newsk->sk_security;
|
[LSM-IPSec]: Per-packet access control.
This patch series implements per packet access control via the
extension of the Linux Security Modules (LSM) interface by hooks in
the XFRM and pfkey subsystems that leverage IPSec security
associations to label packets. Extensions to the SELinux LSM are
included that leverage the patch for this purpose.
This patch implements the changes necessary to the SELinux LSM to
create, deallocate, and use security contexts for policies
(xfrm_policy) and security associations (xfrm_state) that enable
control of a socket's ability to send and receive packets.
Patch purpose:
The patch is designed to enable the SELinux LSM to implement access
control on individual packets based on the strongly authenticated
IPSec security association. Such access controls augment the existing
ones in SELinux based on network interface and IP address. The former
are very coarse-grained, and the latter can be spoofed. By using
IPSec, the SELinux can control access to remote hosts based on
cryptographic keys generated using the IPSec mechanism. This enables
access control on a per-machine basis or per-application if the remote
machine is running the same mechanism and trusted to enforce the
access control policy.
Patch design approach:
The patch's main function is to authorize a socket's access to a IPSec
policy based on their security contexts. Since the communication is
implemented by a security association, the patch ensures that the
security association's negotiated and used have the same security
context. The patch enables allocation and deallocation of such
security contexts for policies and security associations. It also
enables copying of the security context when policies are cloned.
Lastly, the patch ensures that packets that are sent without using a
IPSec security assocation with a security context are allowed to be
sent in that manner.
A presentation available at
www.selinux-symposium.org/2005/presentations/session2/2-3-jaeger.pdf
from the SELinux symposium describes the overall approach.
Patch implementation details:
The function which authorizes a socket to perform a requested
operation (send/receive) on a IPSec policy (xfrm_policy) is
selinux_xfrm_policy_lookup. The Netfilter and rcv_skb hooks ensure
that if a IPSec SA with a securit y association has not been used,
then the socket is allowed to send or receive the packet,
respectively.
The patch implements SELinux function for allocating security contexts
when policies (xfrm_policy) are created via the pfkey or xfrm_user
interfaces via selinux_xfrm_policy_alloc. When a security association
is built, SELinux allocates the security context designated by the
XFRM subsystem which is based on that of the authorized policy via
selinux_xfrm_state_alloc.
When a xfrm_policy is cloned, the security context of that policy, if
any, is copied to the clone via selinux_xfrm_policy_clone.
When a xfrm_policy or xfrm_state is freed, its security context, if
any is also freed at selinux_xfrm_policy_free or
selinux_xfrm_state_free.
Testing:
The SELinux authorization function is tested using ipsec-tools. We
created policies and security associations with particular security
contexts and added SELinux access control policy entries to verify the
authorization decision. We also made sure that packets for which no
security context was supplied (which either did or did not use
security associations) were authorized using an unlabelled context.
Signed-off-by: Trent Jaeger <tjaeger@cse.psu.edu>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
2005-12-14 07:12:40 +00:00
|
|
|
|
2010-04-07 19:08:46 +00:00
|
|
|
newsksec->sid = sksec->sid;
|
|
|
|
newsksec->peer_sid = sksec->peer_sid;
|
|
|
|
newsksec->sclass = sksec->sclass;
|
2006-08-30 00:53:48 +00:00
|
|
|
|
2010-04-07 19:08:46 +00:00
|
|
|
selinux_netlbl_sk_security_reset(newsksec);
|
2006-08-05 06:08:56 +00:00
|
|
|
}
|
|
|
|
|
2006-08-05 06:12:42 +00:00
|
|
|
static void selinux_sk_getsecid(struct sock *sk, u32 *secid)
|
2006-08-05 06:08:56 +00:00
|
|
|
{
|
[LSM-IPSec]: Per-packet access control.
This patch series implements per packet access control via the
extension of the Linux Security Modules (LSM) interface by hooks in
the XFRM and pfkey subsystems that leverage IPSec security
associations to label packets. Extensions to the SELinux LSM are
included that leverage the patch for this purpose.
This patch implements the changes necessary to the SELinux LSM to
create, deallocate, and use security contexts for policies
(xfrm_policy) and security associations (xfrm_state) that enable
control of a socket's ability to send and receive packets.
Patch purpose:
The patch is designed to enable the SELinux LSM to implement access
control on individual packets based on the strongly authenticated
IPSec security association. Such access controls augment the existing
ones in SELinux based on network interface and IP address. The former
are very coarse-grained, and the latter can be spoofed. By using
IPSec, the SELinux can control access to remote hosts based on
cryptographic keys generated using the IPSec mechanism. This enables
access control on a per-machine basis or per-application if the remote
machine is running the same mechanism and trusted to enforce the
access control policy.
Patch design approach:
The patch's main function is to authorize a socket's access to a IPSec
policy based on their security contexts. Since the communication is
implemented by a security association, the patch ensures that the
security association's negotiated and used have the same security
context. The patch enables allocation and deallocation of such
security contexts for policies and security associations. It also
enables copying of the security context when policies are cloned.
Lastly, the patch ensures that packets that are sent without using a
IPSec security assocation with a security context are allowed to be
sent in that manner.
A presentation available at
www.selinux-symposium.org/2005/presentations/session2/2-3-jaeger.pdf
from the SELinux symposium describes the overall approach.
Patch implementation details:
The function which authorizes a socket to perform a requested
operation (send/receive) on a IPSec policy (xfrm_policy) is
selinux_xfrm_policy_lookup. The Netfilter and rcv_skb hooks ensure
that if a IPSec SA with a securit y association has not been used,
then the socket is allowed to send or receive the packet,
respectively.
The patch implements SELinux function for allocating security contexts
when policies (xfrm_policy) are created via the pfkey or xfrm_user
interfaces via selinux_xfrm_policy_alloc. When a security association
is built, SELinux allocates the security context designated by the
XFRM subsystem which is based on that of the authorized policy via
selinux_xfrm_state_alloc.
When a xfrm_policy is cloned, the security context of that policy, if
any, is copied to the clone via selinux_xfrm_policy_clone.
When a xfrm_policy or xfrm_state is freed, its security context, if
any is also freed at selinux_xfrm_policy_free or
selinux_xfrm_state_free.
Testing:
The SELinux authorization function is tested using ipsec-tools. We
created policies and security associations with particular security
contexts and added SELinux access control policy entries to verify the
authorization decision. We also made sure that packets for which no
security context was supplied (which either did or did not use
security associations) were authorized using an unlabelled context.
Signed-off-by: Trent Jaeger <tjaeger@cse.psu.edu>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
2005-12-14 07:12:40 +00:00
|
|
|
if (!sk)
|
2006-08-05 06:12:42 +00:00
|
|
|
*secid = SECINITSID_ANY_SOCKET;
|
2006-08-05 06:08:56 +00:00
|
|
|
else {
|
|
|
|
struct sk_security_struct *sksec = sk->sk_security;
|
[LSM-IPSec]: Per-packet access control.
This patch series implements per packet access control via the
extension of the Linux Security Modules (LSM) interface by hooks in
the XFRM and pfkey subsystems that leverage IPSec security
associations to label packets. Extensions to the SELinux LSM are
included that leverage the patch for this purpose.
This patch implements the changes necessary to the SELinux LSM to
create, deallocate, and use security contexts for policies
(xfrm_policy) and security associations (xfrm_state) that enable
control of a socket's ability to send and receive packets.
Patch purpose:
The patch is designed to enable the SELinux LSM to implement access
control on individual packets based on the strongly authenticated
IPSec security association. Such access controls augment the existing
ones in SELinux based on network interface and IP address. The former
are very coarse-grained, and the latter can be spoofed. By using
IPSec, the SELinux can control access to remote hosts based on
cryptographic keys generated using the IPSec mechanism. This enables
access control on a per-machine basis or per-application if the remote
machine is running the same mechanism and trusted to enforce the
access control policy.
Patch design approach:
The patch's main function is to authorize a socket's access to a IPSec
policy based on their security contexts. Since the communication is
implemented by a security association, the patch ensures that the
security association's negotiated and used have the same security
context. The patch enables allocation and deallocation of such
security contexts for policies and security associations. It also
enables copying of the security context when policies are cloned.
Lastly, the patch ensures that packets that are sent without using a
IPSec security assocation with a security context are allowed to be
sent in that manner.
A presentation available at
www.selinux-symposium.org/2005/presentations/session2/2-3-jaeger.pdf
from the SELinux symposium describes the overall approach.
Patch implementation details:
The function which authorizes a socket to perform a requested
operation (send/receive) on a IPSec policy (xfrm_policy) is
selinux_xfrm_policy_lookup. The Netfilter and rcv_skb hooks ensure
that if a IPSec SA with a securit y association has not been used,
then the socket is allowed to send or receive the packet,
respectively.
The patch implements SELinux function for allocating security contexts
when policies (xfrm_policy) are created via the pfkey or xfrm_user
interfaces via selinux_xfrm_policy_alloc. When a security association
is built, SELinux allocates the security context designated by the
XFRM subsystem which is based on that of the authorized policy via
selinux_xfrm_state_alloc.
When a xfrm_policy is cloned, the security context of that policy, if
any, is copied to the clone via selinux_xfrm_policy_clone.
When a xfrm_policy or xfrm_state is freed, its security context, if
any is also freed at selinux_xfrm_policy_free or
selinux_xfrm_state_free.
Testing:
The SELinux authorization function is tested using ipsec-tools. We
created policies and security associations with particular security
contexts and added SELinux access control policy entries to verify the
authorization decision. We also made sure that packets for which no
security context was supplied (which either did or did not use
security associations) were authorized using an unlabelled context.
Signed-off-by: Trent Jaeger <tjaeger@cse.psu.edu>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
2005-12-14 07:12:40 +00:00
|
|
|
|
2006-08-05 06:12:42 +00:00
|
|
|
*secid = sksec->sid;
|
2006-08-05 06:08:56 +00:00
|
|
|
}
|
[LSM-IPSec]: Per-packet access control.
This patch series implements per packet access control via the
extension of the Linux Security Modules (LSM) interface by hooks in
the XFRM and pfkey subsystems that leverage IPSec security
associations to label packets. Extensions to the SELinux LSM are
included that leverage the patch for this purpose.
This patch implements the changes necessary to the SELinux LSM to
create, deallocate, and use security contexts for policies
(xfrm_policy) and security associations (xfrm_state) that enable
control of a socket's ability to send and receive packets.
Patch purpose:
The patch is designed to enable the SELinux LSM to implement access
control on individual packets based on the strongly authenticated
IPSec security association. Such access controls augment the existing
ones in SELinux based on network interface and IP address. The former
are very coarse-grained, and the latter can be spoofed. By using
IPSec, the SELinux can control access to remote hosts based on
cryptographic keys generated using the IPSec mechanism. This enables
access control on a per-machine basis or per-application if the remote
machine is running the same mechanism and trusted to enforce the
access control policy.
Patch design approach:
The patch's main function is to authorize a socket's access to a IPSec
policy based on their security contexts. Since the communication is
implemented by a security association, the patch ensures that the
security association's negotiated and used have the same security
context. The patch enables allocation and deallocation of such
security contexts for policies and security associations. It also
enables copying of the security context when policies are cloned.
Lastly, the patch ensures that packets that are sent without using a
IPSec security assocation with a security context are allowed to be
sent in that manner.
A presentation available at
www.selinux-symposium.org/2005/presentations/session2/2-3-jaeger.pdf
from the SELinux symposium describes the overall approach.
Patch implementation details:
The function which authorizes a socket to perform a requested
operation (send/receive) on a IPSec policy (xfrm_policy) is
selinux_xfrm_policy_lookup. The Netfilter and rcv_skb hooks ensure
that if a IPSec SA with a securit y association has not been used,
then the socket is allowed to send or receive the packet,
respectively.
The patch implements SELinux function for allocating security contexts
when policies (xfrm_policy) are created via the pfkey or xfrm_user
interfaces via selinux_xfrm_policy_alloc. When a security association
is built, SELinux allocates the security context designated by the
XFRM subsystem which is based on that of the authorized policy via
selinux_xfrm_state_alloc.
When a xfrm_policy is cloned, the security context of that policy, if
any, is copied to the clone via selinux_xfrm_policy_clone.
When a xfrm_policy or xfrm_state is freed, its security context, if
any is also freed at selinux_xfrm_policy_free or
selinux_xfrm_state_free.
Testing:
The SELinux authorization function is tested using ipsec-tools. We
created policies and security associations with particular security
contexts and added SELinux access control policy entries to verify the
authorization decision. We also made sure that packets for which no
security context was supplied (which either did or did not use
security associations) were authorized using an unlabelled context.
Signed-off-by: Trent Jaeger <tjaeger@cse.psu.edu>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
2005-12-14 07:12:40 +00:00
|
|
|
}
|
|
|
|
|
2008-04-17 17:17:49 +00:00
|
|
|
static void selinux_sock_graft(struct sock *sk, struct socket *parent)
|
2006-07-25 06:32:50 +00:00
|
|
|
{
|
|
|
|
struct inode_security_struct *isec = SOCK_INODE(parent)->i_security;
|
|
|
|
struct sk_security_struct *sksec = sk->sk_security;
|
|
|
|
|
2006-09-29 22:50:25 +00:00
|
|
|
if (sk->sk_family == PF_INET || sk->sk_family == PF_INET6 ||
|
|
|
|
sk->sk_family == PF_UNIX)
|
|
|
|
isec->sid = sksec->sid;
|
2008-01-29 13:38:23 +00:00
|
|
|
sksec->sclass = isec->sclass;
|
2006-07-25 06:32:50 +00:00
|
|
|
}
|
|
|
|
|
2006-08-15 07:03:53 +00:00
|
|
|
static int selinux_inet_conn_request(struct sock *sk, struct sk_buff *skb,
|
|
|
|
struct request_sock *req)
|
2006-07-25 06:32:50 +00:00
|
|
|
{
|
|
|
|
struct sk_security_struct *sksec = sk->sk_security;
|
|
|
|
int err;
|
2013-12-03 16:39:13 +00:00
|
|
|
u16 family = req->rsk_ops->family;
|
2013-12-04 21:10:51 +00:00
|
|
|
u32 connsid;
|
2006-07-25 06:32:50 +00:00
|
|
|
u32 peersid;
|
|
|
|
|
2008-10-10 14:16:29 +00:00
|
|
|
err = selinux_skb_peerlbl_sid(skb, family, &peersid);
|
2008-01-29 13:38:23 +00:00
|
|
|
if (err)
|
|
|
|
return err;
|
2013-12-04 21:10:51 +00:00
|
|
|
err = selinux_conn_sid(sksec->sid, peersid, &connsid);
|
|
|
|
if (err)
|
|
|
|
return err;
|
|
|
|
req->secid = connsid;
|
|
|
|
req->peer_secid = peersid;
|
2006-07-28 05:01:34 +00:00
|
|
|
|
2009-03-27 21:10:34 +00:00
|
|
|
return selinux_netlbl_inet_conn_request(req, family);
|
2006-07-25 06:32:50 +00:00
|
|
|
}
|
|
|
|
|
2006-08-15 07:03:53 +00:00
|
|
|
static void selinux_inet_csk_clone(struct sock *newsk,
|
|
|
|
const struct request_sock *req)
|
2006-07-25 06:32:50 +00:00
|
|
|
{
|
|
|
|
struct sk_security_struct *newsksec = newsk->sk_security;
|
|
|
|
|
|
|
|
newsksec->sid = req->secid;
|
2006-11-08 23:04:09 +00:00
|
|
|
newsksec->peer_sid = req->peer_secid;
|
2006-07-25 06:32:50 +00:00
|
|
|
/* NOTE: Ideally, we should also get the isec->sid for the
|
|
|
|
new socket in sync, but we don't have the isec available yet.
|
|
|
|
So we will wait until sock_graft to do it, by which
|
|
|
|
time it will have been created and available. */
|
2006-08-30 00:53:48 +00:00
|
|
|
|
2006-11-17 22:38:53 +00:00
|
|
|
/* We don't need to take any sort of lock here as we are the only
|
|
|
|
* thread with access to newsksec */
|
2009-03-27 21:10:34 +00:00
|
|
|
selinux_netlbl_inet_csk_clone(newsk, req->rsk_ops->family);
|
2006-07-25 06:32:50 +00:00
|
|
|
}
|
|
|
|
|
2008-10-10 14:16:33 +00:00
|
|
|
static void selinux_inet_conn_established(struct sock *sk, struct sk_buff *skb)
|
2006-11-08 23:04:09 +00:00
|
|
|
{
|
2008-10-10 14:16:29 +00:00
|
|
|
u16 family = sk->sk_family;
|
2006-11-08 23:04:09 +00:00
|
|
|
struct sk_security_struct *sksec = sk->sk_security;
|
|
|
|
|
2008-10-10 14:16:29 +00:00
|
|
|
/* handle mapped IPv4 packets arriving via IPv6 sockets */
|
|
|
|
if (family == PF_INET6 && skb->protocol == htons(ETH_P_IP))
|
|
|
|
family = PF_INET;
|
|
|
|
|
|
|
|
selinux_skb_peerlbl_sid(skb, family, &sksec->peer_sid);
|
2006-11-08 23:04:09 +00:00
|
|
|
}
|
|
|
|
|
2013-04-08 17:58:11 +00:00
|
|
|
static void selinux_skb_owned_by(struct sk_buff *skb, struct sock *sk)
|
|
|
|
{
|
|
|
|
skb_set_owner_w(skb, sk);
|
|
|
|
}
|
|
|
|
|
2010-10-13 20:24:41 +00:00
|
|
|
static int selinux_secmark_relabel_packet(u32 sid)
|
|
|
|
{
|
|
|
|
const struct task_security_struct *__tsec;
|
|
|
|
u32 tsid;
|
|
|
|
|
|
|
|
__tsec = current_security();
|
|
|
|
tsid = __tsec->sid;
|
|
|
|
|
|
|
|
return avc_has_perm(tsid, sid, SECCLASS_PACKET, PACKET__RELABELTO, NULL);
|
|
|
|
}
|
|
|
|
|
|
|
|
static void selinux_secmark_refcount_inc(void)
|
|
|
|
{
|
|
|
|
atomic_inc(&selinux_secmark_refcount);
|
|
|
|
}
|
|
|
|
|
|
|
|
static void selinux_secmark_refcount_dec(void)
|
|
|
|
{
|
|
|
|
atomic_dec(&selinux_secmark_refcount);
|
|
|
|
}
|
|
|
|
|
2006-08-15 07:03:53 +00:00
|
|
|
static void selinux_req_classify_flow(const struct request_sock *req,
|
|
|
|
struct flowi *fl)
|
2006-07-25 06:32:50 +00:00
|
|
|
{
|
2011-03-12 05:29:39 +00:00
|
|
|
fl->flowi_secid = req->secid;
|
2006-07-25 06:32:50 +00:00
|
|
|
}
|
|
|
|
|
2013-01-14 07:12:19 +00:00
|
|
|
static int selinux_tun_dev_alloc_security(void **security)
|
|
|
|
{
|
|
|
|
struct tun_security_struct *tunsec;
|
|
|
|
|
|
|
|
tunsec = kzalloc(sizeof(*tunsec), GFP_KERNEL);
|
|
|
|
if (!tunsec)
|
|
|
|
return -ENOMEM;
|
|
|
|
tunsec->sid = current_sid();
|
|
|
|
|
|
|
|
*security = tunsec;
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
|
|
|
static void selinux_tun_dev_free_security(void *security)
|
|
|
|
{
|
|
|
|
kfree(security);
|
|
|
|
}
|
|
|
|
|
2009-08-28 22:12:49 +00:00
|
|
|
static int selinux_tun_dev_create(void)
|
|
|
|
{
|
|
|
|
u32 sid = current_sid();
|
|
|
|
|
|
|
|
/* we aren't taking into account the "sockcreate" SID since the socket
|
|
|
|
* that is being created here is not a socket in the traditional sense,
|
|
|
|
* instead it is a private sock, accessible only to the kernel, and
|
|
|
|
* representing a wide range of network traffic spanning multiple
|
|
|
|
* connections unlike traditional sockets - check the TUN driver to
|
|
|
|
* get a better understanding of why this socket is special */
|
|
|
|
|
|
|
|
return avc_has_perm(sid, sid, SECCLASS_TUN_SOCKET, TUN_SOCKET__CREATE,
|
|
|
|
NULL);
|
|
|
|
}
|
|
|
|
|
2013-01-14 07:12:19 +00:00
|
|
|
static int selinux_tun_dev_attach_queue(void *security)
|
2009-08-28 22:12:49 +00:00
|
|
|
{
|
2013-01-14 07:12:19 +00:00
|
|
|
struct tun_security_struct *tunsec = security;
|
|
|
|
|
|
|
|
return avc_has_perm(current_sid(), tunsec->sid, SECCLASS_TUN_SOCKET,
|
|
|
|
TUN_SOCKET__ATTACH_QUEUE, NULL);
|
|
|
|
}
|
|
|
|
|
|
|
|
static int selinux_tun_dev_attach(struct sock *sk, void *security)
|
|
|
|
{
|
|
|
|
struct tun_security_struct *tunsec = security;
|
2009-08-28 22:12:49 +00:00
|
|
|
struct sk_security_struct *sksec = sk->sk_security;
|
|
|
|
|
|
|
|
/* we don't currently perform any NetLabel based labeling here and it
|
|
|
|
* isn't clear that we would want to do so anyway; while we could apply
|
|
|
|
* labeling without the support of the TUN user the resulting labeled
|
|
|
|
* traffic from the other end of the connection would almost certainly
|
|
|
|
* cause confusion to the TUN user that had no idea network labeling
|
|
|
|
* protocols were being used */
|
|
|
|
|
2013-01-14 07:12:19 +00:00
|
|
|
sksec->sid = tunsec->sid;
|
2009-08-28 22:12:49 +00:00
|
|
|
sksec->sclass = SECCLASS_TUN_SOCKET;
|
2013-01-14 07:12:19 +00:00
|
|
|
|
|
|
|
return 0;
|
2009-08-28 22:12:49 +00:00
|
|
|
}
|
|
|
|
|
2013-01-14 07:12:19 +00:00
|
|
|
static int selinux_tun_dev_open(void *security)
|
2009-08-28 22:12:49 +00:00
|
|
|
{
|
2013-01-14 07:12:19 +00:00
|
|
|
struct tun_security_struct *tunsec = security;
|
2009-08-28 22:12:49 +00:00
|
|
|
u32 sid = current_sid();
|
|
|
|
int err;
|
|
|
|
|
2013-01-14 07:12:19 +00:00
|
|
|
err = avc_has_perm(sid, tunsec->sid, SECCLASS_TUN_SOCKET,
|
2009-08-28 22:12:49 +00:00
|
|
|
TUN_SOCKET__RELABELFROM, NULL);
|
|
|
|
if (err)
|
|
|
|
return err;
|
|
|
|
err = avc_has_perm(sid, sid, SECCLASS_TUN_SOCKET,
|
|
|
|
TUN_SOCKET__RELABELTO, NULL);
|
|
|
|
if (err)
|
|
|
|
return err;
|
2013-01-14 07:12:19 +00:00
|
|
|
tunsec->sid = sid;
|
2009-08-28 22:12:49 +00:00
|
|
|
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
2005-04-16 22:20:36 +00:00
|
|
|
static int selinux_nlmsg_perm(struct sock *sk, struct sk_buff *skb)
|
|
|
|
{
|
|
|
|
int err = 0;
|
|
|
|
u32 perm;
|
|
|
|
struct nlmsghdr *nlh;
|
2010-04-22 18:46:19 +00:00
|
|
|
struct sk_security_struct *sksec = sk->sk_security;
|
2008-04-17 17:17:49 +00:00
|
|
|
|
2013-03-27 06:49:35 +00:00
|
|
|
if (skb->len < NLMSG_HDRLEN) {
|
2005-04-16 22:20:36 +00:00
|
|
|
err = -EINVAL;
|
|
|
|
goto out;
|
|
|
|
}
|
2007-04-26 02:08:35 +00:00
|
|
|
nlh = nlmsg_hdr(skb);
|
2008-04-17 17:17:49 +00:00
|
|
|
|
2010-04-22 18:46:19 +00:00
|
|
|
err = selinux_nlmsg_lookup(sksec->sclass, nlh->nlmsg_type, &perm);
|
2005-04-16 22:20:36 +00:00
|
|
|
if (err) {
|
|
|
|
if (err == -EINVAL) {
|
2005-06-22 14:04:33 +00:00
|
|
|
audit_log(current->audit_context, GFP_KERNEL, AUDIT_SELINUX_ERR,
|
2005-04-16 22:20:36 +00:00
|
|
|
"SELinux: unrecognized netlink message"
|
|
|
|
" type=%hu for sclass=%hu\n",
|
2010-04-22 18:46:19 +00:00
|
|
|
nlh->nlmsg_type, sksec->sclass);
|
2008-11-05 14:34:42 +00:00
|
|
|
if (!selinux_enforcing || security_get_allow_unknown())
|
2005-04-16 22:20:36 +00:00
|
|
|
err = 0;
|
|
|
|
}
|
|
|
|
|
|
|
|
/* Ignore */
|
|
|
|
if (err == -ENOENT)
|
|
|
|
err = 0;
|
|
|
|
goto out;
|
|
|
|
}
|
|
|
|
|
2010-04-22 18:46:19 +00:00
|
|
|
err = sock_has_perm(current, sk, perm);
|
2005-04-16 22:20:36 +00:00
|
|
|
out:
|
|
|
|
return err;
|
|
|
|
}
|
|
|
|
|
|
|
|
#ifdef CONFIG_NETFILTER
|
|
|
|
|
2008-01-29 13:49:27 +00:00
|
|
|
static unsigned int selinux_ip_forward(struct sk_buff *skb, int ifindex,
|
|
|
|
u16 family)
|
2005-04-16 22:20:36 +00:00
|
|
|
{
|
2008-10-10 14:16:31 +00:00
|
|
|
int err;
|
2008-01-29 13:49:27 +00:00
|
|
|
char *addrp;
|
|
|
|
u32 peer_sid;
|
2009-07-14 16:14:09 +00:00
|
|
|
struct common_audit_data ad;
|
2012-04-02 17:15:44 +00:00
|
|
|
struct lsm_network_audit net = {0,};
|
2008-01-29 13:49:27 +00:00
|
|
|
u8 secmark_active;
|
2008-10-10 14:16:32 +00:00
|
|
|
u8 netlbl_active;
|
2008-01-29 13:49:27 +00:00
|
|
|
u8 peerlbl_active;
|
2006-07-25 06:32:50 +00:00
|
|
|
|
2008-01-29 13:49:27 +00:00
|
|
|
if (!selinux_policycap_netpeer)
|
|
|
|
return NF_ACCEPT;
|
2006-07-25 06:32:50 +00:00
|
|
|
|
2008-01-29 13:49:27 +00:00
|
|
|
secmark_active = selinux_secmark_enabled();
|
2008-10-10 14:16:32 +00:00
|
|
|
netlbl_active = netlbl_enabled();
|
2013-05-03 13:05:39 +00:00
|
|
|
peerlbl_active = selinux_peerlbl_enabled();
|
2008-01-29 13:49:27 +00:00
|
|
|
if (!secmark_active && !peerlbl_active)
|
|
|
|
return NF_ACCEPT;
|
2006-07-25 06:32:50 +00:00
|
|
|
|
2008-10-10 14:16:30 +00:00
|
|
|
if (selinux_skb_peerlbl_sid(skb, family, &peer_sid) != 0)
|
|
|
|
return NF_DROP;
|
|
|
|
|
2012-04-04 19:01:43 +00:00
|
|
|
ad.type = LSM_AUDIT_DATA_NET;
|
2012-04-02 17:15:44 +00:00
|
|
|
ad.u.net = &net;
|
|
|
|
ad.u.net->netif = ifindex;
|
|
|
|
ad.u.net->family = family;
|
2008-01-29 13:49:27 +00:00
|
|
|
if (selinux_parse_skb(skb, &ad, &addrp, 1, NULL) != 0)
|
|
|
|
return NF_DROP;
|
|
|
|
|
2008-10-10 14:16:31 +00:00
|
|
|
if (peerlbl_active) {
|
|
|
|
err = selinux_inet_sys_rcv_skb(ifindex, addrp, family,
|
|
|
|
peer_sid, &ad);
|
|
|
|
if (err) {
|
|
|
|
selinux_netlbl_err(skb, err, 1);
|
2008-01-29 13:49:27 +00:00
|
|
|
return NF_DROP;
|
2008-10-10 14:16:31 +00:00
|
|
|
}
|
|
|
|
}
|
2008-01-29 13:49:27 +00:00
|
|
|
|
|
|
|
if (secmark_active)
|
|
|
|
if (avc_has_perm(peer_sid, skb->secmark,
|
|
|
|
SECCLASS_PACKET, PACKET__FORWARD_IN, &ad))
|
|
|
|
return NF_DROP;
|
|
|
|
|
2008-10-10 14:16:32 +00:00
|
|
|
if (netlbl_active)
|
|
|
|
/* we do this in the FORWARD path and not the POST_ROUTING
|
|
|
|
* path because we want to make sure we apply the necessary
|
|
|
|
* labeling before IPsec is applied so we can leverage AH
|
|
|
|
* protection */
|
|
|
|
if (selinux_netlbl_skbuff_setsid(skb, family, peer_sid) != 0)
|
|
|
|
return NF_DROP;
|
|
|
|
|
2008-01-29 13:49:27 +00:00
|
|
|
return NF_ACCEPT;
|
|
|
|
}
|
|
|
|
|
2013-10-10 07:21:55 +00:00
|
|
|
static unsigned int selinux_ipv4_forward(const struct nf_hook_ops *ops,
|
2008-01-29 13:49:27 +00:00
|
|
|
struct sk_buff *skb,
|
|
|
|
const struct net_device *in,
|
|
|
|
const struct net_device *out,
|
|
|
|
int (*okfn)(struct sk_buff *))
|
|
|
|
{
|
|
|
|
return selinux_ip_forward(skb, in->ifindex, PF_INET);
|
|
|
|
}
|
|
|
|
|
|
|
|
#if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
|
2013-10-10 07:21:55 +00:00
|
|
|
static unsigned int selinux_ipv6_forward(const struct nf_hook_ops *ops,
|
2008-01-29 13:49:27 +00:00
|
|
|
struct sk_buff *skb,
|
|
|
|
const struct net_device *in,
|
|
|
|
const struct net_device *out,
|
|
|
|
int (*okfn)(struct sk_buff *))
|
|
|
|
{
|
|
|
|
return selinux_ip_forward(skb, in->ifindex, PF_INET6);
|
|
|
|
}
|
|
|
|
#endif /* IPV6 */
|
|
|
|
|
2008-10-10 14:16:32 +00:00
|
|
|
static unsigned int selinux_ip_output(struct sk_buff *skb,
|
|
|
|
u16 family)
|
|
|
|
{
|
2013-12-04 21:10:45 +00:00
|
|
|
struct sock *sk;
|
2008-10-10 14:16:32 +00:00
|
|
|
u32 sid;
|
|
|
|
|
|
|
|
if (!netlbl_enabled())
|
|
|
|
return NF_ACCEPT;
|
|
|
|
|
|
|
|
/* we do this in the LOCAL_OUT path and not the POST_ROUTING path
|
|
|
|
* because we want to make sure we apply the necessary labeling
|
|
|
|
* before IPsec is applied so we can leverage AH protection */
|
2013-12-04 21:10:45 +00:00
|
|
|
sk = skb->sk;
|
|
|
|
if (sk) {
|
|
|
|
struct sk_security_struct *sksec;
|
|
|
|
|
|
|
|
if (sk->sk_state == TCP_LISTEN)
|
|
|
|
/* if the socket is the listening state then this
|
|
|
|
* packet is a SYN-ACK packet which means it needs to
|
|
|
|
* be labeled based on the connection/request_sock and
|
|
|
|
* not the parent socket. unfortunately, we can't
|
|
|
|
* lookup the request_sock yet as it isn't queued on
|
|
|
|
* the parent socket until after the SYN-ACK is sent.
|
|
|
|
* the "solution" is to simply pass the packet as-is
|
|
|
|
* as any IP option based labeling should be copied
|
|
|
|
* from the initial connection request (in the IP
|
|
|
|
* layer). it is far from ideal, but until we get a
|
|
|
|
* security label in the packet itself this is the
|
|
|
|
* best we can do. */
|
|
|
|
return NF_ACCEPT;
|
|
|
|
|
|
|
|
/* standard practice, label using the parent socket */
|
|
|
|
sksec = sk->sk_security;
|
2008-10-10 14:16:32 +00:00
|
|
|
sid = sksec->sid;
|
|
|
|
} else
|
|
|
|
sid = SECINITSID_KERNEL;
|
|
|
|
if (selinux_netlbl_skbuff_setsid(skb, family, sid) != 0)
|
|
|
|
return NF_DROP;
|
|
|
|
|
|
|
|
return NF_ACCEPT;
|
|
|
|
}
|
|
|
|
|
2013-10-10 07:21:55 +00:00
|
|
|
static unsigned int selinux_ipv4_output(const struct nf_hook_ops *ops,
|
2008-10-10 14:16:32 +00:00
|
|
|
struct sk_buff *skb,
|
|
|
|
const struct net_device *in,
|
|
|
|
const struct net_device *out,
|
|
|
|
int (*okfn)(struct sk_buff *))
|
|
|
|
{
|
|
|
|
return selinux_ip_output(skb, PF_INET);
|
|
|
|
}
|
|
|
|
|
2008-01-29 13:49:27 +00:00
|
|
|
static unsigned int selinux_ip_postroute_compat(struct sk_buff *skb,
|
|
|
|
int ifindex,
|
2008-10-10 14:16:30 +00:00
|
|
|
u16 family)
|
2008-01-29 13:49:27 +00:00
|
|
|
{
|
|
|
|
struct sock *sk = skb->sk;
|
|
|
|
struct sk_security_struct *sksec;
|
2009-07-14 16:14:09 +00:00
|
|
|
struct common_audit_data ad;
|
2012-04-02 17:15:44 +00:00
|
|
|
struct lsm_network_audit net = {0,};
|
2008-10-10 14:16:30 +00:00
|
|
|
char *addrp;
|
|
|
|
u8 proto;
|
2005-04-16 22:20:36 +00:00
|
|
|
|
2008-01-29 13:49:27 +00:00
|
|
|
if (sk == NULL)
|
|
|
|
return NF_ACCEPT;
|
|
|
|
sksec = sk->sk_security;
|
|
|
|
|
2012-04-04 19:01:43 +00:00
|
|
|
ad.type = LSM_AUDIT_DATA_NET;
|
2012-04-02 17:15:44 +00:00
|
|
|
ad.u.net = &net;
|
|
|
|
ad.u.net->netif = ifindex;
|
|
|
|
ad.u.net->family = family;
|
2008-10-10 14:16:30 +00:00
|
|
|
if (selinux_parse_skb(skb, &ad, &addrp, 0, &proto))
|
|
|
|
return NF_DROP;
|
|
|
|
|
2009-03-27 21:10:41 +00:00
|
|
|
if (selinux_secmark_enabled())
|
2008-01-29 13:49:27 +00:00
|
|
|
if (avc_has_perm(sksec->sid, skb->secmark,
|
2008-10-10 14:16:30 +00:00
|
|
|
SECCLASS_PACKET, PACKET__SEND, &ad))
|
2010-11-23 06:28:08 +00:00
|
|
|
return NF_DROP_ERR(-ECONNREFUSED);
|
2008-01-29 13:49:27 +00:00
|
|
|
|
2011-02-23 11:55:21 +00:00
|
|
|
if (selinux_xfrm_postroute_last(sksec->sid, skb, &ad, proto))
|
|
|
|
return NF_DROP_ERR(-ECONNREFUSED);
|
2008-01-29 13:49:27 +00:00
|
|
|
|
|
|
|
return NF_ACCEPT;
|
[SECMARK]: Add new packet controls to SELinux
Add new per-packet access controls to SELinux, replacing the old
packet controls.
Packets are labeled with the iptables SECMARK and CONNSECMARK targets,
then security policy for the packets is enforced with these controls.
To allow for a smooth transition to the new controls, the old code is
still present, but not active by default. To restore previous
behavior, the old controls may be activated at runtime by writing a
'1' to /selinux/compat_net, and also via the kernel boot parameter
selinux_compat_net. Switching between the network control models
requires the security load_policy permission. The old controls will
probably eventually be removed and any continued use is discouraged.
With this patch, the new secmark controls for SElinux are disabled by
default, so existing behavior is entirely preserved, and the user is
not affected at all.
It also provides a config option to enable the secmark controls by
default (which can always be overridden at boot and runtime). It is
also noted in the kconfig help that the user will need updated
userspace if enabling secmark controls for SELinux and that they'll
probably need the SECMARK and CONNMARK targets, and conntrack protocol
helpers, although such decisions are beyond the scope of kernel
configuration.
Signed-off-by: James Morris <jmorris@namei.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-06-09 07:33:33 +00:00
|
|
|
}
|
|
|
|
|
2008-01-29 13:49:27 +00:00
|
|
|
static unsigned int selinux_ip_postroute(struct sk_buff *skb, int ifindex,
|
|
|
|
u16 family)
|
[SECMARK]: Add new packet controls to SELinux
Add new per-packet access controls to SELinux, replacing the old
packet controls.
Packets are labeled with the iptables SECMARK and CONNSECMARK targets,
then security policy for the packets is enforced with these controls.
To allow for a smooth transition to the new controls, the old code is
still present, but not active by default. To restore previous
behavior, the old controls may be activated at runtime by writing a
'1' to /selinux/compat_net, and also via the kernel boot parameter
selinux_compat_net. Switching between the network control models
requires the security load_policy permission. The old controls will
probably eventually be removed and any continued use is discouraged.
With this patch, the new secmark controls for SElinux are disabled by
default, so existing behavior is entirely preserved, and the user is
not affected at all.
It also provides a config option to enable the secmark controls by
default (which can always be overridden at boot and runtime). It is
also noted in the kconfig help that the user will need updated
userspace if enabling secmark controls for SELinux and that they'll
probably need the SECMARK and CONNMARK targets, and conntrack protocol
helpers, although such decisions are beyond the scope of kernel
configuration.
Signed-off-by: James Morris <jmorris@namei.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-06-09 07:33:33 +00:00
|
|
|
{
|
2008-01-29 13:49:27 +00:00
|
|
|
u32 secmark_perm;
|
|
|
|
u32 peer_sid;
|
[SECMARK]: Add new packet controls to SELinux
Add new per-packet access controls to SELinux, replacing the old
packet controls.
Packets are labeled with the iptables SECMARK and CONNSECMARK targets,
then security policy for the packets is enforced with these controls.
To allow for a smooth transition to the new controls, the old code is
still present, but not active by default. To restore previous
behavior, the old controls may be activated at runtime by writing a
'1' to /selinux/compat_net, and also via the kernel boot parameter
selinux_compat_net. Switching between the network control models
requires the security load_policy permission. The old controls will
probably eventually be removed and any continued use is discouraged.
With this patch, the new secmark controls for SElinux are disabled by
default, so existing behavior is entirely preserved, and the user is
not affected at all.
It also provides a config option to enable the secmark controls by
default (which can always be overridden at boot and runtime). It is
also noted in the kconfig help that the user will need updated
userspace if enabling secmark controls for SELinux and that they'll
probably need the SECMARK and CONNMARK targets, and conntrack protocol
helpers, although such decisions are beyond the scope of kernel
configuration.
Signed-off-by: James Morris <jmorris@namei.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-06-09 07:33:33 +00:00
|
|
|
struct sock *sk;
|
2009-07-14 16:14:09 +00:00
|
|
|
struct common_audit_data ad;
|
2012-04-02 17:15:44 +00:00
|
|
|
struct lsm_network_audit net = {0,};
|
2008-01-29 13:49:27 +00:00
|
|
|
char *addrp;
|
|
|
|
u8 secmark_active;
|
|
|
|
u8 peerlbl_active;
|
[SECMARK]: Add new packet controls to SELinux
Add new per-packet access controls to SELinux, replacing the old
packet controls.
Packets are labeled with the iptables SECMARK and CONNSECMARK targets,
then security policy for the packets is enforced with these controls.
To allow for a smooth transition to the new controls, the old code is
still present, but not active by default. To restore previous
behavior, the old controls may be activated at runtime by writing a
'1' to /selinux/compat_net, and also via the kernel boot parameter
selinux_compat_net. Switching between the network control models
requires the security load_policy permission. The old controls will
probably eventually be removed and any continued use is discouraged.
With this patch, the new secmark controls for SElinux are disabled by
default, so existing behavior is entirely preserved, and the user is
not affected at all.
It also provides a config option to enable the secmark controls by
default (which can always be overridden at boot and runtime). It is
also noted in the kconfig help that the user will need updated
userspace if enabling secmark controls for SELinux and that they'll
probably need the SECMARK and CONNMARK targets, and conntrack protocol
helpers, although such decisions are beyond the scope of kernel
configuration.
Signed-off-by: James Morris <jmorris@namei.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-06-09 07:33:33 +00:00
|
|
|
|
2008-01-29 13:49:27 +00:00
|
|
|
/* If any sort of compatibility mode is enabled then handoff processing
|
|
|
|
* to the selinux_ip_postroute_compat() function to deal with the
|
|
|
|
* special handling. We do this in an attempt to keep this function
|
|
|
|
* as fast and as clean as possible. */
|
2009-03-27 21:10:41 +00:00
|
|
|
if (!selinux_policycap_netpeer)
|
2008-10-10 14:16:30 +00:00
|
|
|
return selinux_ip_postroute_compat(skb, ifindex, family);
|
2013-12-10 19:58:01 +00:00
|
|
|
|
|
|
|
secmark_active = selinux_secmark_enabled();
|
|
|
|
peerlbl_active = selinux_peerlbl_enabled();
|
|
|
|
if (!secmark_active && !peerlbl_active)
|
|
|
|
return NF_ACCEPT;
|
|
|
|
|
|
|
|
sk = skb->sk;
|
|
|
|
|
2008-10-28 20:24:06 +00:00
|
|
|
#ifdef CONFIG_XFRM
|
2008-01-29 13:49:27 +00:00
|
|
|
/* If skb->dst->xfrm is non-NULL then the packet is undergoing an IPsec
|
|
|
|
* packet transformation so allow the packet to pass without any checks
|
|
|
|
* since we'll have another chance to perform access control checks
|
|
|
|
* when the packet is on it's final way out.
|
|
|
|
* NOTE: there appear to be some IPv6 multicast cases where skb->dst
|
2013-12-10 19:58:01 +00:00
|
|
|
* is NULL, in this case go ahead and apply access control.
|
|
|
|
* NOTE: if this is a local socket (skb->sk != NULL) that is in the
|
|
|
|
* TCP listening state we cannot wait until the XFRM processing
|
|
|
|
* is done as we will miss out on the SA label if we do;
|
|
|
|
* unfortunately, this means more work, but it is only once per
|
|
|
|
* connection. */
|
|
|
|
if (skb_dst(skb) != NULL && skb_dst(skb)->xfrm != NULL &&
|
|
|
|
!(sk != NULL && sk->sk_state == TCP_LISTEN))
|
2008-01-29 13:49:27 +00:00
|
|
|
return NF_ACCEPT;
|
2008-10-28 20:24:06 +00:00
|
|
|
#endif
|
2008-01-29 13:49:27 +00:00
|
|
|
|
2008-10-10 14:16:30 +00:00
|
|
|
if (sk == NULL) {
|
2013-12-04 21:10:51 +00:00
|
|
|
/* Without an associated socket the packet is either coming
|
|
|
|
* from the kernel or it is being forwarded; check the packet
|
|
|
|
* to determine which and if the packet is being forwarded
|
|
|
|
* query the packet directly to determine the security label. */
|
2011-02-23 11:56:23 +00:00
|
|
|
if (skb->skb_iif) {
|
|
|
|
secmark_perm = PACKET__FORWARD_OUT;
|
2008-10-10 14:16:30 +00:00
|
|
|
if (selinux_skb_peerlbl_sid(skb, family, &peer_sid))
|
2010-11-23 06:28:02 +00:00
|
|
|
return NF_DROP;
|
2011-02-23 11:56:23 +00:00
|
|
|
} else {
|
|
|
|
secmark_perm = PACKET__SEND;
|
2008-10-10 14:16:30 +00:00
|
|
|
peer_sid = SECINITSID_KERNEL;
|
2011-02-23 11:56:23 +00:00
|
|
|
}
|
2013-12-04 21:10:51 +00:00
|
|
|
} else if (sk->sk_state == TCP_LISTEN) {
|
|
|
|
/* Locally generated packet but the associated socket is in the
|
|
|
|
* listening state which means this is a SYN-ACK packet. In
|
|
|
|
* this particular case the correct security label is assigned
|
|
|
|
* to the connection/request_sock but unfortunately we can't
|
|
|
|
* query the request_sock as it isn't queued on the parent
|
|
|
|
* socket until after the SYN-ACK packet is sent; the only
|
|
|
|
* viable choice is to regenerate the label like we do in
|
|
|
|
* selinux_inet_conn_request(). See also selinux_ip_output()
|
|
|
|
* for similar problems. */
|
|
|
|
u32 skb_sid;
|
|
|
|
struct sk_security_struct *sksec = sk->sk_security;
|
|
|
|
if (selinux_skb_peerlbl_sid(skb, family, &skb_sid))
|
|
|
|
return NF_DROP;
|
2013-12-10 19:58:01 +00:00
|
|
|
/* At this point, if the returned skb peerlbl is SECSID_NULL
|
|
|
|
* and the packet has been through at least one XFRM
|
|
|
|
* transformation then we must be dealing with the "final"
|
|
|
|
* form of labeled IPsec packet; since we've already applied
|
|
|
|
* all of our access controls on this packet we can safely
|
|
|
|
* pass the packet. */
|
|
|
|
if (skb_sid == SECSID_NULL) {
|
|
|
|
switch (family) {
|
|
|
|
case PF_INET:
|
|
|
|
if (IPCB(skb)->flags & IPSKB_XFRM_TRANSFORMED)
|
|
|
|
return NF_ACCEPT;
|
|
|
|
break;
|
|
|
|
case PF_INET6:
|
|
|
|
if (IP6CB(skb)->flags & IP6SKB_XFRM_TRANSFORMED)
|
|
|
|
return NF_ACCEPT;
|
|
|
|
default:
|
|
|
|
return NF_DROP_ERR(-ECONNREFUSED);
|
|
|
|
}
|
|
|
|
}
|
2013-12-04 21:10:51 +00:00
|
|
|
if (selinux_conn_sid(sksec->sid, skb_sid, &peer_sid))
|
|
|
|
return NF_DROP;
|
|
|
|
secmark_perm = PACKET__SEND;
|
2008-10-10 14:16:30 +00:00
|
|
|
} else {
|
2013-12-04 21:10:51 +00:00
|
|
|
/* Locally generated packet, fetch the security label from the
|
|
|
|
* associated socket. */
|
2008-01-29 13:49:27 +00:00
|
|
|
struct sk_security_struct *sksec = sk->sk_security;
|
|
|
|
peer_sid = sksec->sid;
|
|
|
|
secmark_perm = PACKET__SEND;
|
|
|
|
}
|
[LSM-IPSec]: Per-packet access control.
This patch series implements per packet access control via the
extension of the Linux Security Modules (LSM) interface by hooks in
the XFRM and pfkey subsystems that leverage IPSec security
associations to label packets. Extensions to the SELinux LSM are
included that leverage the patch for this purpose.
This patch implements the changes necessary to the SELinux LSM to
create, deallocate, and use security contexts for policies
(xfrm_policy) and security associations (xfrm_state) that enable
control of a socket's ability to send and receive packets.
Patch purpose:
The patch is designed to enable the SELinux LSM to implement access
control on individual packets based on the strongly authenticated
IPSec security association. Such access controls augment the existing
ones in SELinux based on network interface and IP address. The former
are very coarse-grained, and the latter can be spoofed. By using
IPSec, the SELinux can control access to remote hosts based on
cryptographic keys generated using the IPSec mechanism. This enables
access control on a per-machine basis or per-application if the remote
machine is running the same mechanism and trusted to enforce the
access control policy.
Patch design approach:
The patch's main function is to authorize a socket's access to a IPSec
policy based on their security contexts. Since the communication is
implemented by a security association, the patch ensures that the
security association's negotiated and used have the same security
context. The patch enables allocation and deallocation of such
security contexts for policies and security associations. It also
enables copying of the security context when policies are cloned.
Lastly, the patch ensures that packets that are sent without using a
IPSec security assocation with a security context are allowed to be
sent in that manner.
A presentation available at
www.selinux-symposium.org/2005/presentations/session2/2-3-jaeger.pdf
from the SELinux symposium describes the overall approach.
Patch implementation details:
The function which authorizes a socket to perform a requested
operation (send/receive) on a IPSec policy (xfrm_policy) is
selinux_xfrm_policy_lookup. The Netfilter and rcv_skb hooks ensure
that if a IPSec SA with a securit y association has not been used,
then the socket is allowed to send or receive the packet,
respectively.
The patch implements SELinux function for allocating security contexts
when policies (xfrm_policy) are created via the pfkey or xfrm_user
interfaces via selinux_xfrm_policy_alloc. When a security association
is built, SELinux allocates the security context designated by the
XFRM subsystem which is based on that of the authorized policy via
selinux_xfrm_state_alloc.
When a xfrm_policy is cloned, the security context of that policy, if
any, is copied to the clone via selinux_xfrm_policy_clone.
When a xfrm_policy or xfrm_state is freed, its security context, if
any is also freed at selinux_xfrm_policy_free or
selinux_xfrm_state_free.
Testing:
The SELinux authorization function is tested using ipsec-tools. We
created policies and security associations with particular security
contexts and added SELinux access control policy entries to verify the
authorization decision. We also made sure that packets for which no
security context was supplied (which either did or did not use
security associations) were authorized using an unlabelled context.
Signed-off-by: Trent Jaeger <tjaeger@cse.psu.edu>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
2005-12-14 07:12:40 +00:00
|
|
|
|
2012-04-04 19:01:43 +00:00
|
|
|
ad.type = LSM_AUDIT_DATA_NET;
|
2012-04-02 17:15:44 +00:00
|
|
|
ad.u.net = &net;
|
|
|
|
ad.u.net->netif = ifindex;
|
|
|
|
ad.u.net->family = family;
|
2008-10-10 14:16:30 +00:00
|
|
|
if (selinux_parse_skb(skb, &ad, &addrp, 0, NULL))
|
2010-11-23 06:28:02 +00:00
|
|
|
return NF_DROP;
|
2008-10-10 14:16:30 +00:00
|
|
|
|
2008-01-29 13:49:27 +00:00
|
|
|
if (secmark_active)
|
|
|
|
if (avc_has_perm(peer_sid, skb->secmark,
|
|
|
|
SECCLASS_PACKET, secmark_perm, &ad))
|
2010-11-16 11:52:57 +00:00
|
|
|
return NF_DROP_ERR(-ECONNREFUSED);
|
2008-01-29 13:49:27 +00:00
|
|
|
|
|
|
|
if (peerlbl_active) {
|
|
|
|
u32 if_sid;
|
|
|
|
u32 node_sid;
|
|
|
|
|
|
|
|
if (sel_netif_sid(ifindex, &if_sid))
|
2010-11-23 06:28:02 +00:00
|
|
|
return NF_DROP;
|
2008-01-29 13:49:27 +00:00
|
|
|
if (avc_has_perm(peer_sid, if_sid,
|
|
|
|
SECCLASS_NETIF, NETIF__EGRESS, &ad))
|
2010-11-16 11:52:57 +00:00
|
|
|
return NF_DROP_ERR(-ECONNREFUSED);
|
2008-01-29 13:49:27 +00:00
|
|
|
|
|
|
|
if (sel_netnode_sid(addrp, family, &node_sid))
|
2010-11-23 06:28:02 +00:00
|
|
|
return NF_DROP;
|
2008-01-29 13:49:27 +00:00
|
|
|
if (avc_has_perm(peer_sid, node_sid,
|
|
|
|
SECCLASS_NODE, NODE__SENDTO, &ad))
|
2010-11-16 11:52:57 +00:00
|
|
|
return NF_DROP_ERR(-ECONNREFUSED);
|
2008-01-29 13:49:27 +00:00
|
|
|
}
|
[SECMARK]: Add new packet controls to SELinux
Add new per-packet access controls to SELinux, replacing the old
packet controls.
Packets are labeled with the iptables SECMARK and CONNSECMARK targets,
then security policy for the packets is enforced with these controls.
To allow for a smooth transition to the new controls, the old code is
still present, but not active by default. To restore previous
behavior, the old controls may be activated at runtime by writing a
'1' to /selinux/compat_net, and also via the kernel boot parameter
selinux_compat_net. Switching between the network control models
requires the security load_policy permission. The old controls will
probably eventually be removed and any continued use is discouraged.
With this patch, the new secmark controls for SElinux are disabled by
default, so existing behavior is entirely preserved, and the user is
not affected at all.
It also provides a config option to enable the secmark controls by
default (which can always be overridden at boot and runtime). It is
also noted in the kconfig help that the user will need updated
userspace if enabling secmark controls for SELinux and that they'll
probably need the SECMARK and CONNMARK targets, and conntrack protocol
helpers, although such decisions are beyond the scope of kernel
configuration.
Signed-off-by: James Morris <jmorris@namei.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-06-09 07:33:33 +00:00
|
|
|
|
2008-01-29 13:49:27 +00:00
|
|
|
return NF_ACCEPT;
|
2005-04-16 22:20:36 +00:00
|
|
|
}
|
|
|
|
|
2013-10-10 07:21:55 +00:00
|
|
|
static unsigned int selinux_ipv4_postroute(const struct nf_hook_ops *ops,
|
2008-01-29 13:49:27 +00:00
|
|
|
struct sk_buff *skb,
|
|
|
|
const struct net_device *in,
|
|
|
|
const struct net_device *out,
|
|
|
|
int (*okfn)(struct sk_buff *))
|
2005-04-16 22:20:36 +00:00
|
|
|
{
|
2008-01-29 13:49:27 +00:00
|
|
|
return selinux_ip_postroute(skb, out->ifindex, PF_INET);
|
2005-04-16 22:20:36 +00:00
|
|
|
}
|
|
|
|
|
|
|
|
#if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
|
2013-10-10 07:21:55 +00:00
|
|
|
static unsigned int selinux_ipv6_postroute(const struct nf_hook_ops *ops,
|
2008-01-29 13:49:27 +00:00
|
|
|
struct sk_buff *skb,
|
|
|
|
const struct net_device *in,
|
|
|
|
const struct net_device *out,
|
|
|
|
int (*okfn)(struct sk_buff *))
|
2005-04-16 22:20:36 +00:00
|
|
|
{
|
2008-01-29 13:49:27 +00:00
|
|
|
return selinux_ip_postroute(skb, out->ifindex, PF_INET6);
|
2005-04-16 22:20:36 +00:00
|
|
|
}
|
|
|
|
#endif /* IPV6 */
|
|
|
|
|
|
|
|
#endif /* CONFIG_NETFILTER */
|
|
|
|
|
|
|
|
static int selinux_netlink_send(struct sock *sk, struct sk_buff *skb)
|
|
|
|
{
|
|
|
|
int err;
|
|
|
|
|
2009-02-12 20:01:04 +00:00
|
|
|
err = cap_netlink_send(sk, skb);
|
2005-04-16 22:20:36 +00:00
|
|
|
if (err)
|
|
|
|
return err;
|
|
|
|
|
2009-10-01 18:48:23 +00:00
|
|
|
return selinux_nlmsg_perm(sk, skb);
|
2005-04-16 22:20:36 +00:00
|
|
|
}
|
|
|
|
|
|
|
|
static int ipc_alloc_security(struct task_struct *task,
|
|
|
|
struct kern_ipc_perm *perm,
|
|
|
|
u16 sclass)
|
|
|
|
{
|
|
|
|
struct ipc_security_struct *isec;
|
2008-11-13 23:39:19 +00:00
|
|
|
u32 sid;
|
2005-04-16 22:20:36 +00:00
|
|
|
|
2005-10-30 22:59:21 +00:00
|
|
|
isec = kzalloc(sizeof(struct ipc_security_struct), GFP_KERNEL);
|
2005-04-16 22:20:36 +00:00
|
|
|
if (!isec)
|
|
|
|
return -ENOMEM;
|
|
|
|
|
2008-11-13 23:39:19 +00:00
|
|
|
sid = task_sid(task);
|
2005-04-16 22:20:36 +00:00
|
|
|
isec->sclass = sclass;
|
2008-11-13 23:39:19 +00:00
|
|
|
isec->sid = sid;
|
2005-04-16 22:20:36 +00:00
|
|
|
perm->security = isec;
|
|
|
|
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
|
|
|
static void ipc_free_security(struct kern_ipc_perm *perm)
|
|
|
|
{
|
|
|
|
struct ipc_security_struct *isec = perm->security;
|
|
|
|
perm->security = NULL;
|
|
|
|
kfree(isec);
|
|
|
|
}
|
|
|
|
|
|
|
|
static int msg_msg_alloc_security(struct msg_msg *msg)
|
|
|
|
{
|
|
|
|
struct msg_security_struct *msec;
|
|
|
|
|
2005-10-30 22:59:21 +00:00
|
|
|
msec = kzalloc(sizeof(struct msg_security_struct), GFP_KERNEL);
|
2005-04-16 22:20:36 +00:00
|
|
|
if (!msec)
|
|
|
|
return -ENOMEM;
|
|
|
|
|
|
|
|
msec->sid = SECINITSID_UNLABELED;
|
|
|
|
msg->security = msec;
|
|
|
|
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
|
|
|
static void msg_msg_free_security(struct msg_msg *msg)
|
|
|
|
{
|
|
|
|
struct msg_security_struct *msec = msg->security;
|
|
|
|
|
|
|
|
msg->security = NULL;
|
|
|
|
kfree(msec);
|
|
|
|
}
|
|
|
|
|
|
|
|
static int ipc_has_perm(struct kern_ipc_perm *ipc_perms,
|
2005-05-01 15:58:39 +00:00
|
|
|
u32 perms)
|
2005-04-16 22:20:36 +00:00
|
|
|
{
|
|
|
|
struct ipc_security_struct *isec;
|
2009-07-14 16:14:09 +00:00
|
|
|
struct common_audit_data ad;
|
2008-11-13 23:39:19 +00:00
|
|
|
u32 sid = current_sid();
|
2005-04-16 22:20:36 +00:00
|
|
|
|
|
|
|
isec = ipc_perms->security;
|
|
|
|
|
2012-04-04 19:01:43 +00:00
|
|
|
ad.type = LSM_AUDIT_DATA_IPC;
|
2005-04-16 22:20:36 +00:00
|
|
|
ad.u.ipc_id = ipc_perms->key;
|
|
|
|
|
2008-11-13 23:39:19 +00:00
|
|
|
return avc_has_perm(sid, isec->sid, isec->sclass, perms, &ad);
|
2005-04-16 22:20:36 +00:00
|
|
|
}
|
|
|
|
|
|
|
|
static int selinux_msg_msg_alloc_security(struct msg_msg *msg)
|
|
|
|
{
|
|
|
|
return msg_msg_alloc_security(msg);
|
|
|
|
}
|
|
|
|
|
|
|
|
static void selinux_msg_msg_free_security(struct msg_msg *msg)
|
|
|
|
{
|
|
|
|
msg_msg_free_security(msg);
|
|
|
|
}
|
|
|
|
|
|
|
|
/* message queue security operations */
|
|
|
|
static int selinux_msg_queue_alloc_security(struct msg_queue *msq)
|
|
|
|
{
|
|
|
|
struct ipc_security_struct *isec;
|
2009-07-14 16:14:09 +00:00
|
|
|
struct common_audit_data ad;
|
2008-11-13 23:39:19 +00:00
|
|
|
u32 sid = current_sid();
|
2005-04-16 22:20:36 +00:00
|
|
|
int rc;
|
|
|
|
|
|
|
|
rc = ipc_alloc_security(current, &msq->q_perm, SECCLASS_MSGQ);
|
|
|
|
if (rc)
|
|
|
|
return rc;
|
|
|
|
|
|
|
|
isec = msq->q_perm.security;
|
|
|
|
|
2012-04-04 19:01:43 +00:00
|
|
|
ad.type = LSM_AUDIT_DATA_IPC;
|
2008-04-17 17:17:49 +00:00
|
|
|
ad.u.ipc_id = msq->q_perm.key;
|
2005-04-16 22:20:36 +00:00
|
|
|
|
2008-11-13 23:39:19 +00:00
|
|
|
rc = avc_has_perm(sid, isec->sid, SECCLASS_MSGQ,
|
2005-04-16 22:20:36 +00:00
|
|
|
MSGQ__CREATE, &ad);
|
|
|
|
if (rc) {
|
|
|
|
ipc_free_security(&msq->q_perm);
|
|
|
|
return rc;
|
|
|
|
}
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
|
|
|
static void selinux_msg_queue_free_security(struct msg_queue *msq)
|
|
|
|
{
|
|
|
|
ipc_free_security(&msq->q_perm);
|
|
|
|
}
|
|
|
|
|
|
|
|
static int selinux_msg_queue_associate(struct msg_queue *msq, int msqflg)
|
|
|
|
{
|
|
|
|
struct ipc_security_struct *isec;
|
2009-07-14 16:14:09 +00:00
|
|
|
struct common_audit_data ad;
|
2008-11-13 23:39:19 +00:00
|
|
|
u32 sid = current_sid();
|
2005-04-16 22:20:36 +00:00
|
|
|
|
|
|
|
isec = msq->q_perm.security;
|
|
|
|
|
2012-04-04 19:01:43 +00:00
|
|
|
ad.type = LSM_AUDIT_DATA_IPC;
|
2005-04-16 22:20:36 +00:00
|
|
|
ad.u.ipc_id = msq->q_perm.key;
|
|
|
|
|
2008-11-13 23:39:19 +00:00
|
|
|
return avc_has_perm(sid, isec->sid, SECCLASS_MSGQ,
|
2005-04-16 22:20:36 +00:00
|
|
|
MSGQ__ASSOCIATE, &ad);
|
|
|
|
}
|
|
|
|
|
|
|
|
static int selinux_msg_queue_msgctl(struct msg_queue *msq, int cmd)
|
|
|
|
{
|
|
|
|
int err;
|
|
|
|
int perms;
|
|
|
|
|
2008-04-17 17:17:49 +00:00
|
|
|
switch (cmd) {
|
2005-04-16 22:20:36 +00:00
|
|
|
case IPC_INFO:
|
|
|
|
case MSG_INFO:
|
|
|
|
/* No specific object, just general system-wide information. */
|
|
|
|
return task_has_system(current, SYSTEM__IPC_INFO);
|
|
|
|
case IPC_STAT:
|
|
|
|
case MSG_STAT:
|
|
|
|
perms = MSGQ__GETATTR | MSGQ__ASSOCIATE;
|
|
|
|
break;
|
|
|
|
case IPC_SET:
|
|
|
|
perms = MSGQ__SETATTR;
|
|
|
|
break;
|
|
|
|
case IPC_RMID:
|
|
|
|
perms = MSGQ__DESTROY;
|
|
|
|
break;
|
|
|
|
default:
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
2005-05-01 15:58:39 +00:00
|
|
|
err = ipc_has_perm(&msq->q_perm, perms);
|
2005-04-16 22:20:36 +00:00
|
|
|
return err;
|
|
|
|
}
|
|
|
|
|
|
|
|
static int selinux_msg_queue_msgsnd(struct msg_queue *msq, struct msg_msg *msg, int msqflg)
|
|
|
|
{
|
|
|
|
struct ipc_security_struct *isec;
|
|
|
|
struct msg_security_struct *msec;
|
2009-07-14 16:14:09 +00:00
|
|
|
struct common_audit_data ad;
|
2008-11-13 23:39:19 +00:00
|
|
|
u32 sid = current_sid();
|
2005-04-16 22:20:36 +00:00
|
|
|
int rc;
|
|
|
|
|
|
|
|
isec = msq->q_perm.security;
|
|
|
|
msec = msg->security;
|
|
|
|
|
|
|
|
/*
|
|
|
|
* First time through, need to assign label to the message
|
|
|
|
*/
|
|
|
|
if (msec->sid == SECINITSID_UNLABELED) {
|
|
|
|
/*
|
|
|
|
* Compute new sid based on current process and
|
|
|
|
* message queue this message will be stored in
|
|
|
|
*/
|
2008-11-13 23:39:19 +00:00
|
|
|
rc = security_transition_sid(sid, isec->sid, SECCLASS_MSG,
|
SELinux: Use dentry name in new object labeling
Currently SELinux has rules which label new objects according to 3 criteria.
The label of the process creating the object, the label of the parent
directory, and the type of object (reg, dir, char, block, etc.) This patch
adds a 4th criteria, the dentry name, thus we can distinguish between
creating a file in an etc_t directory called shadow and one called motd.
There is no file globbing, regex parsing, or anything mystical. Either the
policy exactly (strcmp) matches the dentry name of the object or it doesn't.
This patch has no changes from today if policy does not implement the new
rules.
Signed-off-by: Eric Paris <eparis@redhat.com>
2011-02-01 16:05:40 +00:00
|
|
|
NULL, &msec->sid);
|
2005-04-16 22:20:36 +00:00
|
|
|
if (rc)
|
|
|
|
return rc;
|
|
|
|
}
|
|
|
|
|
2012-04-04 19:01:43 +00:00
|
|
|
ad.type = LSM_AUDIT_DATA_IPC;
|
2005-04-16 22:20:36 +00:00
|
|
|
ad.u.ipc_id = msq->q_perm.key;
|
|
|
|
|
|
|
|
/* Can this process write to the queue? */
|
2008-11-13 23:39:19 +00:00
|
|
|
rc = avc_has_perm(sid, isec->sid, SECCLASS_MSGQ,
|
2005-04-16 22:20:36 +00:00
|
|
|
MSGQ__WRITE, &ad);
|
|
|
|
if (!rc)
|
|
|
|
/* Can this process send the message */
|
2008-11-13 23:39:19 +00:00
|
|
|
rc = avc_has_perm(sid, msec->sid, SECCLASS_MSG,
|
|
|
|
MSG__SEND, &ad);
|
2005-04-16 22:20:36 +00:00
|
|
|
if (!rc)
|
|
|
|
/* Can the message be put in the queue? */
|
2008-11-13 23:39:19 +00:00
|
|
|
rc = avc_has_perm(msec->sid, isec->sid, SECCLASS_MSGQ,
|
|
|
|
MSGQ__ENQUEUE, &ad);
|
2005-04-16 22:20:36 +00:00
|
|
|
|
|
|
|
return rc;
|
|
|
|
}
|
|
|
|
|
|
|
|
static int selinux_msg_queue_msgrcv(struct msg_queue *msq, struct msg_msg *msg,
|
|
|
|
struct task_struct *target,
|
|
|
|
long type, int mode)
|
|
|
|
{
|
|
|
|
struct ipc_security_struct *isec;
|
|
|
|
struct msg_security_struct *msec;
|
2009-07-14 16:14:09 +00:00
|
|
|
struct common_audit_data ad;
|
2008-11-13 23:39:19 +00:00
|
|
|
u32 sid = task_sid(target);
|
2005-04-16 22:20:36 +00:00
|
|
|
int rc;
|
|
|
|
|
|
|
|
isec = msq->q_perm.security;
|
|
|
|
msec = msg->security;
|
|
|
|
|
2012-04-04 19:01:43 +00:00
|
|
|
ad.type = LSM_AUDIT_DATA_IPC;
|
2008-04-17 17:17:49 +00:00
|
|
|
ad.u.ipc_id = msq->q_perm.key;
|
2005-04-16 22:20:36 +00:00
|
|
|
|
2008-11-13 23:39:19 +00:00
|
|
|
rc = avc_has_perm(sid, isec->sid,
|
2005-04-16 22:20:36 +00:00
|
|
|
SECCLASS_MSGQ, MSGQ__READ, &ad);
|
|
|
|
if (!rc)
|
2008-11-13 23:39:19 +00:00
|
|
|
rc = avc_has_perm(sid, msec->sid,
|
2005-04-16 22:20:36 +00:00
|
|
|
SECCLASS_MSG, MSG__RECEIVE, &ad);
|
|
|
|
return rc;
|
|
|
|
}
|
|
|
|
|
|
|
|
/* Shared Memory security operations */
|
|
|
|
static int selinux_shm_alloc_security(struct shmid_kernel *shp)
|
|
|
|
{
|
|
|
|
struct ipc_security_struct *isec;
|
2009-07-14 16:14:09 +00:00
|
|
|
struct common_audit_data ad;
|
2008-11-13 23:39:19 +00:00
|
|
|
u32 sid = current_sid();
|
2005-04-16 22:20:36 +00:00
|
|
|
int rc;
|
|
|
|
|
|
|
|
rc = ipc_alloc_security(current, &shp->shm_perm, SECCLASS_SHM);
|
|
|
|
if (rc)
|
|
|
|
return rc;
|
|
|
|
|
|
|
|
isec = shp->shm_perm.security;
|
|
|
|
|
2012-04-04 19:01:43 +00:00
|
|
|
ad.type = LSM_AUDIT_DATA_IPC;
|
2008-04-17 17:17:49 +00:00
|
|
|
ad.u.ipc_id = shp->shm_perm.key;
|
2005-04-16 22:20:36 +00:00
|
|
|
|
2008-11-13 23:39:19 +00:00
|
|
|
rc = avc_has_perm(sid, isec->sid, SECCLASS_SHM,
|
2005-04-16 22:20:36 +00:00
|
|
|
SHM__CREATE, &ad);
|
|
|
|
if (rc) {
|
|
|
|
ipc_free_security(&shp->shm_perm);
|
|
|
|
return rc;
|
|
|
|
}
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
|
|
|
static void selinux_shm_free_security(struct shmid_kernel *shp)
|
|
|
|
{
|
|
|
|
ipc_free_security(&shp->shm_perm);
|
|
|
|
}
|
|
|
|
|
|
|
|
static int selinux_shm_associate(struct shmid_kernel *shp, int shmflg)
|
|
|
|
{
|
|
|
|
struct ipc_security_struct *isec;
|
2009-07-14 16:14:09 +00:00
|
|
|
struct common_audit_data ad;
|
2008-11-13 23:39:19 +00:00
|
|
|
u32 sid = current_sid();
|
2005-04-16 22:20:36 +00:00
|
|
|
|
|
|
|
isec = shp->shm_perm.security;
|
|
|
|
|
2012-04-04 19:01:43 +00:00
|
|
|
ad.type = LSM_AUDIT_DATA_IPC;
|
2005-04-16 22:20:36 +00:00
|
|
|
ad.u.ipc_id = shp->shm_perm.key;
|
|
|
|
|
2008-11-13 23:39:19 +00:00
|
|
|
return avc_has_perm(sid, isec->sid, SECCLASS_SHM,
|
2005-04-16 22:20:36 +00:00
|
|
|
SHM__ASSOCIATE, &ad);
|
|
|
|
}
|
|
|
|
|
|
|
|
/* Note, at this point, shp is locked down */
|
|
|
|
static int selinux_shm_shmctl(struct shmid_kernel *shp, int cmd)
|
|
|
|
{
|
|
|
|
int perms;
|
|
|
|
int err;
|
|
|
|
|
2008-04-17 17:17:49 +00:00
|
|
|
switch (cmd) {
|
2005-04-16 22:20:36 +00:00
|
|
|
case IPC_INFO:
|
|
|
|
case SHM_INFO:
|
|
|
|
/* No specific object, just general system-wide information. */
|
|
|
|
return task_has_system(current, SYSTEM__IPC_INFO);
|
|
|
|
case IPC_STAT:
|
|
|
|
case SHM_STAT:
|
|
|
|
perms = SHM__GETATTR | SHM__ASSOCIATE;
|
|
|
|
break;
|
|
|
|
case IPC_SET:
|
|
|
|
perms = SHM__SETATTR;
|
|
|
|
break;
|
|
|
|
case SHM_LOCK:
|
|
|
|
case SHM_UNLOCK:
|
|
|
|
perms = SHM__LOCK;
|
|
|
|
break;
|
|
|
|
case IPC_RMID:
|
|
|
|
perms = SHM__DESTROY;
|
|
|
|
break;
|
|
|
|
default:
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
2005-05-01 15:58:39 +00:00
|
|
|
err = ipc_has_perm(&shp->shm_perm, perms);
|
2005-04-16 22:20:36 +00:00
|
|
|
return err;
|
|
|
|
}
|
|
|
|
|
|
|
|
static int selinux_shm_shmat(struct shmid_kernel *shp,
|
|
|
|
char __user *shmaddr, int shmflg)
|
|
|
|
{
|
|
|
|
u32 perms;
|
|
|
|
|
|
|
|
if (shmflg & SHM_RDONLY)
|
|
|
|
perms = SHM__READ;
|
|
|
|
else
|
|
|
|
perms = SHM__READ | SHM__WRITE;
|
|
|
|
|
2005-05-01 15:58:39 +00:00
|
|
|
return ipc_has_perm(&shp->shm_perm, perms);
|
2005-04-16 22:20:36 +00:00
|
|
|
}
|
|
|
|
|
|
|
|
/* Semaphore security operations */
|
|
|
|
static int selinux_sem_alloc_security(struct sem_array *sma)
|
|
|
|
{
|
|
|
|
struct ipc_security_struct *isec;
|
2009-07-14 16:14:09 +00:00
|
|
|
struct common_audit_data ad;
|
2008-11-13 23:39:19 +00:00
|
|
|
u32 sid = current_sid();
|
2005-04-16 22:20:36 +00:00
|
|
|
int rc;
|
|
|
|
|
|
|
|
rc = ipc_alloc_security(current, &sma->sem_perm, SECCLASS_SEM);
|
|
|
|
if (rc)
|
|
|
|
return rc;
|
|
|
|
|
|
|
|
isec = sma->sem_perm.security;
|
|
|
|
|
2012-04-04 19:01:43 +00:00
|
|
|
ad.type = LSM_AUDIT_DATA_IPC;
|
2008-04-17 17:17:49 +00:00
|
|
|
ad.u.ipc_id = sma->sem_perm.key;
|
2005-04-16 22:20:36 +00:00
|
|
|
|
2008-11-13 23:39:19 +00:00
|
|
|
rc = avc_has_perm(sid, isec->sid, SECCLASS_SEM,
|
2005-04-16 22:20:36 +00:00
|
|
|
SEM__CREATE, &ad);
|
|
|
|
if (rc) {
|
|
|
|
ipc_free_security(&sma->sem_perm);
|
|
|
|
return rc;
|
|
|
|
}
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
|
|
|
static void selinux_sem_free_security(struct sem_array *sma)
|
|
|
|
{
|
|
|
|
ipc_free_security(&sma->sem_perm);
|
|
|
|
}
|
|
|
|
|
|
|
|
static int selinux_sem_associate(struct sem_array *sma, int semflg)
|
|
|
|
{
|
|
|
|
struct ipc_security_struct *isec;
|
2009-07-14 16:14:09 +00:00
|
|
|
struct common_audit_data ad;
|
2008-11-13 23:39:19 +00:00
|
|
|
u32 sid = current_sid();
|
2005-04-16 22:20:36 +00:00
|
|
|
|
|
|
|
isec = sma->sem_perm.security;
|
|
|
|
|
2012-04-04 19:01:43 +00:00
|
|
|
ad.type = LSM_AUDIT_DATA_IPC;
|
2005-04-16 22:20:36 +00:00
|
|
|
ad.u.ipc_id = sma->sem_perm.key;
|
|
|
|
|
2008-11-13 23:39:19 +00:00
|
|
|
return avc_has_perm(sid, isec->sid, SECCLASS_SEM,
|
2005-04-16 22:20:36 +00:00
|
|
|
SEM__ASSOCIATE, &ad);
|
|
|
|
}
|
|
|
|
|
|
|
|
/* Note, at this point, sma is locked down */
|
|
|
|
static int selinux_sem_semctl(struct sem_array *sma, int cmd)
|
|
|
|
{
|
|
|
|
int err;
|
|
|
|
u32 perms;
|
|
|
|
|
2008-04-17 17:17:49 +00:00
|
|
|
switch (cmd) {
|
2005-04-16 22:20:36 +00:00
|
|
|
case IPC_INFO:
|
|
|
|
case SEM_INFO:
|
|
|
|
/* No specific object, just general system-wide information. */
|
|
|
|
return task_has_system(current, SYSTEM__IPC_INFO);
|
|
|
|
case GETPID:
|
|
|
|
case GETNCNT:
|
|
|
|
case GETZCNT:
|
|
|
|
perms = SEM__GETATTR;
|
|
|
|
break;
|
|
|
|
case GETVAL:
|
|
|
|
case GETALL:
|
|
|
|
perms = SEM__READ;
|
|
|
|
break;
|
|
|
|
case SETVAL:
|
|
|
|
case SETALL:
|
|
|
|
perms = SEM__WRITE;
|
|
|
|
break;
|
|
|
|
case IPC_RMID:
|
|
|
|
perms = SEM__DESTROY;
|
|
|
|
break;
|
|
|
|
case IPC_SET:
|
|
|
|
perms = SEM__SETATTR;
|
|
|
|
break;
|
|
|
|
case IPC_STAT:
|
|
|
|
case SEM_STAT:
|
|
|
|
perms = SEM__GETATTR | SEM__ASSOCIATE;
|
|
|
|
break;
|
|
|
|
default:
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
2005-05-01 15:58:39 +00:00
|
|
|
err = ipc_has_perm(&sma->sem_perm, perms);
|
2005-04-16 22:20:36 +00:00
|
|
|
return err;
|
|
|
|
}
|
|
|
|
|
|
|
|
static int selinux_sem_semop(struct sem_array *sma,
|
|
|
|
struct sembuf *sops, unsigned nsops, int alter)
|
|
|
|
{
|
|
|
|
u32 perms;
|
|
|
|
|
|
|
|
if (alter)
|
|
|
|
perms = SEM__READ | SEM__WRITE;
|
|
|
|
else
|
|
|
|
perms = SEM__READ;
|
|
|
|
|
2005-05-01 15:58:39 +00:00
|
|
|
return ipc_has_perm(&sma->sem_perm, perms);
|
2005-04-16 22:20:36 +00:00
|
|
|
}
|
|
|
|
|
|
|
|
static int selinux_ipc_permission(struct kern_ipc_perm *ipcp, short flag)
|
|
|
|
{
|
|
|
|
u32 av = 0;
|
|
|
|
|
|
|
|
av = 0;
|
|
|
|
if (flag & S_IRUGO)
|
|
|
|
av |= IPC__UNIX_READ;
|
|
|
|
if (flag & S_IWUGO)
|
|
|
|
av |= IPC__UNIX_WRITE;
|
|
|
|
|
|
|
|
if (av == 0)
|
|
|
|
return 0;
|
|
|
|
|
2005-05-01 15:58:39 +00:00
|
|
|
return ipc_has_perm(ipcp, av);
|
2005-04-16 22:20:36 +00:00
|
|
|
}
|
|
|
|
|
2008-03-01 19:52:30 +00:00
|
|
|
static void selinux_ipc_getsecid(struct kern_ipc_perm *ipcp, u32 *secid)
|
|
|
|
{
|
|
|
|
struct ipc_security_struct *isec = ipcp->security;
|
|
|
|
*secid = isec->sid;
|
|
|
|
}
|
|
|
|
|
2008-04-17 17:17:49 +00:00
|
|
|
static void selinux_d_instantiate(struct dentry *dentry, struct inode *inode)
|
2005-04-16 22:20:36 +00:00
|
|
|
{
|
|
|
|
if (inode)
|
|
|
|
inode_doinit_with_dentry(inode, dentry);
|
|
|
|
}
|
|
|
|
|
|
|
|
static int selinux_getprocattr(struct task_struct *p,
|
2007-03-12 16:17:58 +00:00
|
|
|
char *name, char **value)
|
2005-04-16 22:20:36 +00:00
|
|
|
{
|
2008-11-13 23:39:19 +00:00
|
|
|
const struct task_security_struct *__tsec;
|
2005-11-03 17:15:16 +00:00
|
|
|
u32 sid;
|
2005-04-16 22:20:36 +00:00
|
|
|
int error;
|
2007-03-12 16:17:58 +00:00
|
|
|
unsigned len;
|
2005-04-16 22:20:36 +00:00
|
|
|
|
|
|
|
if (current != p) {
|
2008-11-13 23:39:26 +00:00
|
|
|
error = current_has_perm(p, PROCESS__GETATTR);
|
2005-04-16 22:20:36 +00:00
|
|
|
if (error)
|
|
|
|
return error;
|
|
|
|
}
|
|
|
|
|
2008-11-13 23:39:19 +00:00
|
|
|
rcu_read_lock();
|
|
|
|
__tsec = __task_cred(p)->security;
|
2005-04-16 22:20:36 +00:00
|
|
|
|
|
|
|
if (!strcmp(name, "current"))
|
2008-11-13 23:39:19 +00:00
|
|
|
sid = __tsec->sid;
|
2005-04-16 22:20:36 +00:00
|
|
|
else if (!strcmp(name, "prev"))
|
2008-11-13 23:39:19 +00:00
|
|
|
sid = __tsec->osid;
|
2005-04-16 22:20:36 +00:00
|
|
|
else if (!strcmp(name, "exec"))
|
2008-11-13 23:39:19 +00:00
|
|
|
sid = __tsec->exec_sid;
|
2005-04-16 22:20:36 +00:00
|
|
|
else if (!strcmp(name, "fscreate"))
|
2008-11-13 23:39:19 +00:00
|
|
|
sid = __tsec->create_sid;
|
2006-06-26 07:24:57 +00:00
|
|
|
else if (!strcmp(name, "keycreate"))
|
2008-11-13 23:39:19 +00:00
|
|
|
sid = __tsec->keycreate_sid;
|
2006-06-26 07:26:03 +00:00
|
|
|
else if (!strcmp(name, "sockcreate"))
|
2008-11-13 23:39:19 +00:00
|
|
|
sid = __tsec->sockcreate_sid;
|
2005-04-16 22:20:36 +00:00
|
|
|
else
|
2008-11-13 23:39:19 +00:00
|
|
|
goto invalid;
|
|
|
|
rcu_read_unlock();
|
2005-04-16 22:20:36 +00:00
|
|
|
|
|
|
|
if (!sid)
|
|
|
|
return 0;
|
|
|
|
|
2007-03-12 16:17:58 +00:00
|
|
|
error = security_sid_to_context(sid, value, &len);
|
|
|
|
if (error)
|
|
|
|
return error;
|
|
|
|
return len;
|
2008-11-13 23:39:19 +00:00
|
|
|
|
|
|
|
invalid:
|
|
|
|
rcu_read_unlock();
|
|
|
|
return -EINVAL;
|
2005-04-16 22:20:36 +00:00
|
|
|
}
|
|
|
|
|
|
|
|
static int selinux_setprocattr(struct task_struct *p,
|
|
|
|
char *name, void *value, size_t size)
|
|
|
|
{
|
|
|
|
struct task_security_struct *tsec;
|
2008-03-26 22:46:39 +00:00
|
|
|
struct task_struct *tracer;
|
CRED: Inaugurate COW credentials
Inaugurate copy-on-write credentials management. This uses RCU to manage the
credentials pointer in the task_struct with respect to accesses by other tasks.
A process may only modify its own credentials, and so does not need locking to
access or modify its own credentials.
A mutex (cred_replace_mutex) is added to the task_struct to control the effect
of PTRACE_ATTACHED on credential calculations, particularly with respect to
execve().
With this patch, the contents of an active credentials struct may not be
changed directly; rather a new set of credentials must be prepared, modified
and committed using something like the following sequence of events:
struct cred *new = prepare_creds();
int ret = blah(new);
if (ret < 0) {
abort_creds(new);
return ret;
}
return commit_creds(new);
There are some exceptions to this rule: the keyrings pointed to by the active
credentials may be instantiated - keyrings violate the COW rule as managing
COW keyrings is tricky, given that it is possible for a task to directly alter
the keys in a keyring in use by another task.
To help enforce this, various pointers to sets of credentials, such as those in
the task_struct, are declared const. The purpose of this is compile-time
discouragement of altering credentials through those pointers. Once a set of
credentials has been made public through one of these pointers, it may not be
modified, except under special circumstances:
(1) Its reference count may incremented and decremented.
(2) The keyrings to which it points may be modified, but not replaced.
The only safe way to modify anything else is to create a replacement and commit
using the functions described in Documentation/credentials.txt (which will be
added by a later patch).
This patch and the preceding patches have been tested with the LTP SELinux
testsuite.
This patch makes several logical sets of alteration:
(1) execve().
This now prepares and commits credentials in various places in the
security code rather than altering the current creds directly.
(2) Temporary credential overrides.
do_coredump() and sys_faccessat() now prepare their own credentials and
temporarily override the ones currently on the acting thread, whilst
preventing interference from other threads by holding cred_replace_mutex
on the thread being dumped.
This will be replaced in a future patch by something that hands down the
credentials directly to the functions being called, rather than altering
the task's objective credentials.
(3) LSM interface.
A number of functions have been changed, added or removed:
(*) security_capset_check(), ->capset_check()
(*) security_capset_set(), ->capset_set()
Removed in favour of security_capset().
(*) security_capset(), ->capset()
New. This is passed a pointer to the new creds, a pointer to the old
creds and the proposed capability sets. It should fill in the new
creds or return an error. All pointers, barring the pointer to the
new creds, are now const.
(*) security_bprm_apply_creds(), ->bprm_apply_creds()
Changed; now returns a value, which will cause the process to be
killed if it's an error.
(*) security_task_alloc(), ->task_alloc_security()
Removed in favour of security_prepare_creds().
(*) security_cred_free(), ->cred_free()
New. Free security data attached to cred->security.
(*) security_prepare_creds(), ->cred_prepare()
New. Duplicate any security data attached to cred->security.
(*) security_commit_creds(), ->cred_commit()
New. Apply any security effects for the upcoming installation of new
security by commit_creds().
(*) security_task_post_setuid(), ->task_post_setuid()
Removed in favour of security_task_fix_setuid().
(*) security_task_fix_setuid(), ->task_fix_setuid()
Fix up the proposed new credentials for setuid(). This is used by
cap_set_fix_setuid() to implicitly adjust capabilities in line with
setuid() changes. Changes are made to the new credentials, rather
than the task itself as in security_task_post_setuid().
(*) security_task_reparent_to_init(), ->task_reparent_to_init()
Removed. Instead the task being reparented to init is referred
directly to init's credentials.
NOTE! This results in the loss of some state: SELinux's osid no
longer records the sid of the thread that forked it.
(*) security_key_alloc(), ->key_alloc()
(*) security_key_permission(), ->key_permission()
Changed. These now take cred pointers rather than task pointers to
refer to the security context.
(4) sys_capset().
This has been simplified and uses less locking. The LSM functions it
calls have been merged.
(5) reparent_to_kthreadd().
This gives the current thread the same credentials as init by simply using
commit_thread() to point that way.
(6) __sigqueue_alloc() and switch_uid()
__sigqueue_alloc() can't stop the target task from changing its creds
beneath it, so this function gets a reference to the currently applicable
user_struct which it then passes into the sigqueue struct it returns if
successful.
switch_uid() is now called from commit_creds(), and possibly should be
folded into that. commit_creds() should take care of protecting
__sigqueue_alloc().
(7) [sg]et[ug]id() and co and [sg]et_current_groups.
The set functions now all use prepare_creds(), commit_creds() and
abort_creds() to build and check a new set of credentials before applying
it.
security_task_set[ug]id() is called inside the prepared section. This
guarantees that nothing else will affect the creds until we've finished.
The calling of set_dumpable() has been moved into commit_creds().
Much of the functionality of set_user() has been moved into
commit_creds().
The get functions all simply access the data directly.
(8) security_task_prctl() and cap_task_prctl().
security_task_prctl() has been modified to return -ENOSYS if it doesn't
want to handle a function, or otherwise return the return value directly
rather than through an argument.
Additionally, cap_task_prctl() now prepares a new set of credentials, even
if it doesn't end up using it.
(9) Keyrings.
A number of changes have been made to the keyrings code:
(a) switch_uid_keyring(), copy_keys(), exit_keys() and suid_keys() have
all been dropped and built in to the credentials functions directly.
They may want separating out again later.
(b) key_alloc() and search_process_keyrings() now take a cred pointer
rather than a task pointer to specify the security context.
(c) copy_creds() gives a new thread within the same thread group a new
thread keyring if its parent had one, otherwise it discards the thread
keyring.
(d) The authorisation key now points directly to the credentials to extend
the search into rather pointing to the task that carries them.
(e) Installing thread, process or session keyrings causes a new set of
credentials to be created, even though it's not strictly necessary for
process or session keyrings (they're shared).
(10) Usermode helper.
The usermode helper code now carries a cred struct pointer in its
subprocess_info struct instead of a new session keyring pointer. This set
of credentials is derived from init_cred and installed on the new process
after it has been cloned.
call_usermodehelper_setup() allocates the new credentials and
call_usermodehelper_freeinfo() discards them if they haven't been used. A
special cred function (prepare_usermodeinfo_creds()) is provided
specifically for call_usermodehelper_setup() to call.
call_usermodehelper_setkeys() adjusts the credentials to sport the
supplied keyring as the new session keyring.
(11) SELinux.
SELinux has a number of changes, in addition to those to support the LSM
interface changes mentioned above:
(a) selinux_setprocattr() no longer does its check for whether the
current ptracer can access processes with the new SID inside the lock
that covers getting the ptracer's SID. Whilst this lock ensures that
the check is done with the ptracer pinned, the result is only valid
until the lock is released, so there's no point doing it inside the
lock.
(12) is_single_threaded().
This function has been extracted from selinux_setprocattr() and put into
a file of its own in the lib/ directory as join_session_keyring() now
wants to use it too.
The code in SELinux just checked to see whether a task shared mm_structs
with other tasks (CLONE_VM), but that isn't good enough. We really want
to know if they're part of the same thread group (CLONE_THREAD).
(13) nfsd.
The NFS server daemon now has to use the COW credentials to set the
credentials it is going to use. It really needs to pass the credentials
down to the functions it calls, but it can't do that until other patches
in this series have been applied.
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: James Morris <jmorris@namei.org>
Signed-off-by: James Morris <jmorris@namei.org>
2008-11-13 23:39:23 +00:00
|
|
|
struct cred *new;
|
|
|
|
u32 sid = 0, ptsid;
|
2005-04-16 22:20:36 +00:00
|
|
|
int error;
|
|
|
|
char *str = value;
|
|
|
|
|
|
|
|
if (current != p) {
|
|
|
|
/* SELinux only allows a process to change its own
|
|
|
|
security attributes. */
|
|
|
|
return -EACCES;
|
|
|
|
}
|
|
|
|
|
|
|
|
/*
|
|
|
|
* Basic control over ability to set these attributes at all.
|
|
|
|
* current == p, but we'll pass them separately in case the
|
|
|
|
* above restriction is ever removed.
|
|
|
|
*/
|
|
|
|
if (!strcmp(name, "exec"))
|
2008-11-13 23:39:26 +00:00
|
|
|
error = current_has_perm(p, PROCESS__SETEXEC);
|
2005-04-16 22:20:36 +00:00
|
|
|
else if (!strcmp(name, "fscreate"))
|
2008-11-13 23:39:26 +00:00
|
|
|
error = current_has_perm(p, PROCESS__SETFSCREATE);
|
2006-06-26 07:24:57 +00:00
|
|
|
else if (!strcmp(name, "keycreate"))
|
2008-11-13 23:39:26 +00:00
|
|
|
error = current_has_perm(p, PROCESS__SETKEYCREATE);
|
2006-06-26 07:26:03 +00:00
|
|
|
else if (!strcmp(name, "sockcreate"))
|
2008-11-13 23:39:26 +00:00
|
|
|
error = current_has_perm(p, PROCESS__SETSOCKCREATE);
|
2005-04-16 22:20:36 +00:00
|
|
|
else if (!strcmp(name, "current"))
|
2008-11-13 23:39:26 +00:00
|
|
|
error = current_has_perm(p, PROCESS__SETCURRENT);
|
2005-04-16 22:20:36 +00:00
|
|
|
else
|
|
|
|
error = -EINVAL;
|
|
|
|
if (error)
|
|
|
|
return error;
|
|
|
|
|
|
|
|
/* Obtain a SID for the context, if one was specified. */
|
|
|
|
if (size && str[1] && str[1] != '\n') {
|
|
|
|
if (str[size-1] == '\n') {
|
|
|
|
str[size-1] = 0;
|
|
|
|
size--;
|
|
|
|
}
|
2014-03-07 11:44:19 +00:00
|
|
|
error = security_context_to_sid(value, size, &sid, GFP_KERNEL);
|
2008-05-07 17:03:20 +00:00
|
|
|
if (error == -EINVAL && !strcmp(name, "fscreate")) {
|
2012-04-04 17:45:49 +00:00
|
|
|
if (!capable(CAP_MAC_ADMIN)) {
|
|
|
|
struct audit_buffer *ab;
|
|
|
|
size_t audit_size;
|
|
|
|
|
|
|
|
/* We strip a nul only if it is at the end, otherwise the
|
|
|
|
* context contains a nul and we should audit that */
|
|
|
|
if (str[size - 1] == '\0')
|
|
|
|
audit_size = size - 1;
|
|
|
|
else
|
|
|
|
audit_size = size;
|
|
|
|
ab = audit_log_start(current->audit_context, GFP_ATOMIC, AUDIT_SELINUX_ERR);
|
|
|
|
audit_log_format(ab, "op=fscreate invalid_context=");
|
|
|
|
audit_log_n_untrustedstring(ab, value, audit_size);
|
|
|
|
audit_log_end(ab);
|
|
|
|
|
2008-05-07 17:03:20 +00:00
|
|
|
return error;
|
2012-04-04 17:45:49 +00:00
|
|
|
}
|
2008-05-07 17:03:20 +00:00
|
|
|
error = security_context_to_sid_force(value, size,
|
|
|
|
&sid);
|
|
|
|
}
|
2005-04-16 22:20:36 +00:00
|
|
|
if (error)
|
|
|
|
return error;
|
|
|
|
}
|
|
|
|
|
CRED: Inaugurate COW credentials
Inaugurate copy-on-write credentials management. This uses RCU to manage the
credentials pointer in the task_struct with respect to accesses by other tasks.
A process may only modify its own credentials, and so does not need locking to
access or modify its own credentials.
A mutex (cred_replace_mutex) is added to the task_struct to control the effect
of PTRACE_ATTACHED on credential calculations, particularly with respect to
execve().
With this patch, the contents of an active credentials struct may not be
changed directly; rather a new set of credentials must be prepared, modified
and committed using something like the following sequence of events:
struct cred *new = prepare_creds();
int ret = blah(new);
if (ret < 0) {
abort_creds(new);
return ret;
}
return commit_creds(new);
There are some exceptions to this rule: the keyrings pointed to by the active
credentials may be instantiated - keyrings violate the COW rule as managing
COW keyrings is tricky, given that it is possible for a task to directly alter
the keys in a keyring in use by another task.
To help enforce this, various pointers to sets of credentials, such as those in
the task_struct, are declared const. The purpose of this is compile-time
discouragement of altering credentials through those pointers. Once a set of
credentials has been made public through one of these pointers, it may not be
modified, except under special circumstances:
(1) Its reference count may incremented and decremented.
(2) The keyrings to which it points may be modified, but not replaced.
The only safe way to modify anything else is to create a replacement and commit
using the functions described in Documentation/credentials.txt (which will be
added by a later patch).
This patch and the preceding patches have been tested with the LTP SELinux
testsuite.
This patch makes several logical sets of alteration:
(1) execve().
This now prepares and commits credentials in various places in the
security code rather than altering the current creds directly.
(2) Temporary credential overrides.
do_coredump() and sys_faccessat() now prepare their own credentials and
temporarily override the ones currently on the acting thread, whilst
preventing interference from other threads by holding cred_replace_mutex
on the thread being dumped.
This will be replaced in a future patch by something that hands down the
credentials directly to the functions being called, rather than altering
the task's objective credentials.
(3) LSM interface.
A number of functions have been changed, added or removed:
(*) security_capset_check(), ->capset_check()
(*) security_capset_set(), ->capset_set()
Removed in favour of security_capset().
(*) security_capset(), ->capset()
New. This is passed a pointer to the new creds, a pointer to the old
creds and the proposed capability sets. It should fill in the new
creds or return an error. All pointers, barring the pointer to the
new creds, are now const.
(*) security_bprm_apply_creds(), ->bprm_apply_creds()
Changed; now returns a value, which will cause the process to be
killed if it's an error.
(*) security_task_alloc(), ->task_alloc_security()
Removed in favour of security_prepare_creds().
(*) security_cred_free(), ->cred_free()
New. Free security data attached to cred->security.
(*) security_prepare_creds(), ->cred_prepare()
New. Duplicate any security data attached to cred->security.
(*) security_commit_creds(), ->cred_commit()
New. Apply any security effects for the upcoming installation of new
security by commit_creds().
(*) security_task_post_setuid(), ->task_post_setuid()
Removed in favour of security_task_fix_setuid().
(*) security_task_fix_setuid(), ->task_fix_setuid()
Fix up the proposed new credentials for setuid(). This is used by
cap_set_fix_setuid() to implicitly adjust capabilities in line with
setuid() changes. Changes are made to the new credentials, rather
than the task itself as in security_task_post_setuid().
(*) security_task_reparent_to_init(), ->task_reparent_to_init()
Removed. Instead the task being reparented to init is referred
directly to init's credentials.
NOTE! This results in the loss of some state: SELinux's osid no
longer records the sid of the thread that forked it.
(*) security_key_alloc(), ->key_alloc()
(*) security_key_permission(), ->key_permission()
Changed. These now take cred pointers rather than task pointers to
refer to the security context.
(4) sys_capset().
This has been simplified and uses less locking. The LSM functions it
calls have been merged.
(5) reparent_to_kthreadd().
This gives the current thread the same credentials as init by simply using
commit_thread() to point that way.
(6) __sigqueue_alloc() and switch_uid()
__sigqueue_alloc() can't stop the target task from changing its creds
beneath it, so this function gets a reference to the currently applicable
user_struct which it then passes into the sigqueue struct it returns if
successful.
switch_uid() is now called from commit_creds(), and possibly should be
folded into that. commit_creds() should take care of protecting
__sigqueue_alloc().
(7) [sg]et[ug]id() and co and [sg]et_current_groups.
The set functions now all use prepare_creds(), commit_creds() and
abort_creds() to build and check a new set of credentials before applying
it.
security_task_set[ug]id() is called inside the prepared section. This
guarantees that nothing else will affect the creds until we've finished.
The calling of set_dumpable() has been moved into commit_creds().
Much of the functionality of set_user() has been moved into
commit_creds().
The get functions all simply access the data directly.
(8) security_task_prctl() and cap_task_prctl().
security_task_prctl() has been modified to return -ENOSYS if it doesn't
want to handle a function, or otherwise return the return value directly
rather than through an argument.
Additionally, cap_task_prctl() now prepares a new set of credentials, even
if it doesn't end up using it.
(9) Keyrings.
A number of changes have been made to the keyrings code:
(a) switch_uid_keyring(), copy_keys(), exit_keys() and suid_keys() have
all been dropped and built in to the credentials functions directly.
They may want separating out again later.
(b) key_alloc() and search_process_keyrings() now take a cred pointer
rather than a task pointer to specify the security context.
(c) copy_creds() gives a new thread within the same thread group a new
thread keyring if its parent had one, otherwise it discards the thread
keyring.
(d) The authorisation key now points directly to the credentials to extend
the search into rather pointing to the task that carries them.
(e) Installing thread, process or session keyrings causes a new set of
credentials to be created, even though it's not strictly necessary for
process or session keyrings (they're shared).
(10) Usermode helper.
The usermode helper code now carries a cred struct pointer in its
subprocess_info struct instead of a new session keyring pointer. This set
of credentials is derived from init_cred and installed on the new process
after it has been cloned.
call_usermodehelper_setup() allocates the new credentials and
call_usermodehelper_freeinfo() discards them if they haven't been used. A
special cred function (prepare_usermodeinfo_creds()) is provided
specifically for call_usermodehelper_setup() to call.
call_usermodehelper_setkeys() adjusts the credentials to sport the
supplied keyring as the new session keyring.
(11) SELinux.
SELinux has a number of changes, in addition to those to support the LSM
interface changes mentioned above:
(a) selinux_setprocattr() no longer does its check for whether the
current ptracer can access processes with the new SID inside the lock
that covers getting the ptracer's SID. Whilst this lock ensures that
the check is done with the ptracer pinned, the result is only valid
until the lock is released, so there's no point doing it inside the
lock.
(12) is_single_threaded().
This function has been extracted from selinux_setprocattr() and put into
a file of its own in the lib/ directory as join_session_keyring() now
wants to use it too.
The code in SELinux just checked to see whether a task shared mm_structs
with other tasks (CLONE_VM), but that isn't good enough. We really want
to know if they're part of the same thread group (CLONE_THREAD).
(13) nfsd.
The NFS server daemon now has to use the COW credentials to set the
credentials it is going to use. It really needs to pass the credentials
down to the functions it calls, but it can't do that until other patches
in this series have been applied.
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: James Morris <jmorris@namei.org>
Signed-off-by: James Morris <jmorris@namei.org>
2008-11-13 23:39:23 +00:00
|
|
|
new = prepare_creds();
|
|
|
|
if (!new)
|
|
|
|
return -ENOMEM;
|
|
|
|
|
2005-04-16 22:20:36 +00:00
|
|
|
/* Permission checking based on the specified context is
|
|
|
|
performed during the actual operation (execve,
|
|
|
|
open/mkdir/...), when we know the full context of the
|
CRED: Inaugurate COW credentials
Inaugurate copy-on-write credentials management. This uses RCU to manage the
credentials pointer in the task_struct with respect to accesses by other tasks.
A process may only modify its own credentials, and so does not need locking to
access or modify its own credentials.
A mutex (cred_replace_mutex) is added to the task_struct to control the effect
of PTRACE_ATTACHED on credential calculations, particularly with respect to
execve().
With this patch, the contents of an active credentials struct may not be
changed directly; rather a new set of credentials must be prepared, modified
and committed using something like the following sequence of events:
struct cred *new = prepare_creds();
int ret = blah(new);
if (ret < 0) {
abort_creds(new);
return ret;
}
return commit_creds(new);
There are some exceptions to this rule: the keyrings pointed to by the active
credentials may be instantiated - keyrings violate the COW rule as managing
COW keyrings is tricky, given that it is possible for a task to directly alter
the keys in a keyring in use by another task.
To help enforce this, various pointers to sets of credentials, such as those in
the task_struct, are declared const. The purpose of this is compile-time
discouragement of altering credentials through those pointers. Once a set of
credentials has been made public through one of these pointers, it may not be
modified, except under special circumstances:
(1) Its reference count may incremented and decremented.
(2) The keyrings to which it points may be modified, but not replaced.
The only safe way to modify anything else is to create a replacement and commit
using the functions described in Documentation/credentials.txt (which will be
added by a later patch).
This patch and the preceding patches have been tested with the LTP SELinux
testsuite.
This patch makes several logical sets of alteration:
(1) execve().
This now prepares and commits credentials in various places in the
security code rather than altering the current creds directly.
(2) Temporary credential overrides.
do_coredump() and sys_faccessat() now prepare their own credentials and
temporarily override the ones currently on the acting thread, whilst
preventing interference from other threads by holding cred_replace_mutex
on the thread being dumped.
This will be replaced in a future patch by something that hands down the
credentials directly to the functions being called, rather than altering
the task's objective credentials.
(3) LSM interface.
A number of functions have been changed, added or removed:
(*) security_capset_check(), ->capset_check()
(*) security_capset_set(), ->capset_set()
Removed in favour of security_capset().
(*) security_capset(), ->capset()
New. This is passed a pointer to the new creds, a pointer to the old
creds and the proposed capability sets. It should fill in the new
creds or return an error. All pointers, barring the pointer to the
new creds, are now const.
(*) security_bprm_apply_creds(), ->bprm_apply_creds()
Changed; now returns a value, which will cause the process to be
killed if it's an error.
(*) security_task_alloc(), ->task_alloc_security()
Removed in favour of security_prepare_creds().
(*) security_cred_free(), ->cred_free()
New. Free security data attached to cred->security.
(*) security_prepare_creds(), ->cred_prepare()
New. Duplicate any security data attached to cred->security.
(*) security_commit_creds(), ->cred_commit()
New. Apply any security effects for the upcoming installation of new
security by commit_creds().
(*) security_task_post_setuid(), ->task_post_setuid()
Removed in favour of security_task_fix_setuid().
(*) security_task_fix_setuid(), ->task_fix_setuid()
Fix up the proposed new credentials for setuid(). This is used by
cap_set_fix_setuid() to implicitly adjust capabilities in line with
setuid() changes. Changes are made to the new credentials, rather
than the task itself as in security_task_post_setuid().
(*) security_task_reparent_to_init(), ->task_reparent_to_init()
Removed. Instead the task being reparented to init is referred
directly to init's credentials.
NOTE! This results in the loss of some state: SELinux's osid no
longer records the sid of the thread that forked it.
(*) security_key_alloc(), ->key_alloc()
(*) security_key_permission(), ->key_permission()
Changed. These now take cred pointers rather than task pointers to
refer to the security context.
(4) sys_capset().
This has been simplified and uses less locking. The LSM functions it
calls have been merged.
(5) reparent_to_kthreadd().
This gives the current thread the same credentials as init by simply using
commit_thread() to point that way.
(6) __sigqueue_alloc() and switch_uid()
__sigqueue_alloc() can't stop the target task from changing its creds
beneath it, so this function gets a reference to the currently applicable
user_struct which it then passes into the sigqueue struct it returns if
successful.
switch_uid() is now called from commit_creds(), and possibly should be
folded into that. commit_creds() should take care of protecting
__sigqueue_alloc().
(7) [sg]et[ug]id() and co and [sg]et_current_groups.
The set functions now all use prepare_creds(), commit_creds() and
abort_creds() to build and check a new set of credentials before applying
it.
security_task_set[ug]id() is called inside the prepared section. This
guarantees that nothing else will affect the creds until we've finished.
The calling of set_dumpable() has been moved into commit_creds().
Much of the functionality of set_user() has been moved into
commit_creds().
The get functions all simply access the data directly.
(8) security_task_prctl() and cap_task_prctl().
security_task_prctl() has been modified to return -ENOSYS if it doesn't
want to handle a function, or otherwise return the return value directly
rather than through an argument.
Additionally, cap_task_prctl() now prepares a new set of credentials, even
if it doesn't end up using it.
(9) Keyrings.
A number of changes have been made to the keyrings code:
(a) switch_uid_keyring(), copy_keys(), exit_keys() and suid_keys() have
all been dropped and built in to the credentials functions directly.
They may want separating out again later.
(b) key_alloc() and search_process_keyrings() now take a cred pointer
rather than a task pointer to specify the security context.
(c) copy_creds() gives a new thread within the same thread group a new
thread keyring if its parent had one, otherwise it discards the thread
keyring.
(d) The authorisation key now points directly to the credentials to extend
the search into rather pointing to the task that carries them.
(e) Installing thread, process or session keyrings causes a new set of
credentials to be created, even though it's not strictly necessary for
process or session keyrings (they're shared).
(10) Usermode helper.
The usermode helper code now carries a cred struct pointer in its
subprocess_info struct instead of a new session keyring pointer. This set
of credentials is derived from init_cred and installed on the new process
after it has been cloned.
call_usermodehelper_setup() allocates the new credentials and
call_usermodehelper_freeinfo() discards them if they haven't been used. A
special cred function (prepare_usermodeinfo_creds()) is provided
specifically for call_usermodehelper_setup() to call.
call_usermodehelper_setkeys() adjusts the credentials to sport the
supplied keyring as the new session keyring.
(11) SELinux.
SELinux has a number of changes, in addition to those to support the LSM
interface changes mentioned above:
(a) selinux_setprocattr() no longer does its check for whether the
current ptracer can access processes with the new SID inside the lock
that covers getting the ptracer's SID. Whilst this lock ensures that
the check is done with the ptracer pinned, the result is only valid
until the lock is released, so there's no point doing it inside the
lock.
(12) is_single_threaded().
This function has been extracted from selinux_setprocattr() and put into
a file of its own in the lib/ directory as join_session_keyring() now
wants to use it too.
The code in SELinux just checked to see whether a task shared mm_structs
with other tasks (CLONE_VM), but that isn't good enough. We really want
to know if they're part of the same thread group (CLONE_THREAD).
(13) nfsd.
The NFS server daemon now has to use the COW credentials to set the
credentials it is going to use. It really needs to pass the credentials
down to the functions it calls, but it can't do that until other patches
in this series have been applied.
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: James Morris <jmorris@namei.org>
Signed-off-by: James Morris <jmorris@namei.org>
2008-11-13 23:39:23 +00:00
|
|
|
operation. See selinux_bprm_set_creds for the execve
|
2005-04-16 22:20:36 +00:00
|
|
|
checks and may_create for the file creation checks. The
|
|
|
|
operation will then fail if the context is not permitted. */
|
CRED: Inaugurate COW credentials
Inaugurate copy-on-write credentials management. This uses RCU to manage the
credentials pointer in the task_struct with respect to accesses by other tasks.
A process may only modify its own credentials, and so does not need locking to
access or modify its own credentials.
A mutex (cred_replace_mutex) is added to the task_struct to control the effect
of PTRACE_ATTACHED on credential calculations, particularly with respect to
execve().
With this patch, the contents of an active credentials struct may not be
changed directly; rather a new set of credentials must be prepared, modified
and committed using something like the following sequence of events:
struct cred *new = prepare_creds();
int ret = blah(new);
if (ret < 0) {
abort_creds(new);
return ret;
}
return commit_creds(new);
There are some exceptions to this rule: the keyrings pointed to by the active
credentials may be instantiated - keyrings violate the COW rule as managing
COW keyrings is tricky, given that it is possible for a task to directly alter
the keys in a keyring in use by another task.
To help enforce this, various pointers to sets of credentials, such as those in
the task_struct, are declared const. The purpose of this is compile-time
discouragement of altering credentials through those pointers. Once a set of
credentials has been made public through one of these pointers, it may not be
modified, except under special circumstances:
(1) Its reference count may incremented and decremented.
(2) The keyrings to which it points may be modified, but not replaced.
The only safe way to modify anything else is to create a replacement and commit
using the functions described in Documentation/credentials.txt (which will be
added by a later patch).
This patch and the preceding patches have been tested with the LTP SELinux
testsuite.
This patch makes several logical sets of alteration:
(1) execve().
This now prepares and commits credentials in various places in the
security code rather than altering the current creds directly.
(2) Temporary credential overrides.
do_coredump() and sys_faccessat() now prepare their own credentials and
temporarily override the ones currently on the acting thread, whilst
preventing interference from other threads by holding cred_replace_mutex
on the thread being dumped.
This will be replaced in a future patch by something that hands down the
credentials directly to the functions being called, rather than altering
the task's objective credentials.
(3) LSM interface.
A number of functions have been changed, added or removed:
(*) security_capset_check(), ->capset_check()
(*) security_capset_set(), ->capset_set()
Removed in favour of security_capset().
(*) security_capset(), ->capset()
New. This is passed a pointer to the new creds, a pointer to the old
creds and the proposed capability sets. It should fill in the new
creds or return an error. All pointers, barring the pointer to the
new creds, are now const.
(*) security_bprm_apply_creds(), ->bprm_apply_creds()
Changed; now returns a value, which will cause the process to be
killed if it's an error.
(*) security_task_alloc(), ->task_alloc_security()
Removed in favour of security_prepare_creds().
(*) security_cred_free(), ->cred_free()
New. Free security data attached to cred->security.
(*) security_prepare_creds(), ->cred_prepare()
New. Duplicate any security data attached to cred->security.
(*) security_commit_creds(), ->cred_commit()
New. Apply any security effects for the upcoming installation of new
security by commit_creds().
(*) security_task_post_setuid(), ->task_post_setuid()
Removed in favour of security_task_fix_setuid().
(*) security_task_fix_setuid(), ->task_fix_setuid()
Fix up the proposed new credentials for setuid(). This is used by
cap_set_fix_setuid() to implicitly adjust capabilities in line with
setuid() changes. Changes are made to the new credentials, rather
than the task itself as in security_task_post_setuid().
(*) security_task_reparent_to_init(), ->task_reparent_to_init()
Removed. Instead the task being reparented to init is referred
directly to init's credentials.
NOTE! This results in the loss of some state: SELinux's osid no
longer records the sid of the thread that forked it.
(*) security_key_alloc(), ->key_alloc()
(*) security_key_permission(), ->key_permission()
Changed. These now take cred pointers rather than task pointers to
refer to the security context.
(4) sys_capset().
This has been simplified and uses less locking. The LSM functions it
calls have been merged.
(5) reparent_to_kthreadd().
This gives the current thread the same credentials as init by simply using
commit_thread() to point that way.
(6) __sigqueue_alloc() and switch_uid()
__sigqueue_alloc() can't stop the target task from changing its creds
beneath it, so this function gets a reference to the currently applicable
user_struct which it then passes into the sigqueue struct it returns if
successful.
switch_uid() is now called from commit_creds(), and possibly should be
folded into that. commit_creds() should take care of protecting
__sigqueue_alloc().
(7) [sg]et[ug]id() and co and [sg]et_current_groups.
The set functions now all use prepare_creds(), commit_creds() and
abort_creds() to build and check a new set of credentials before applying
it.
security_task_set[ug]id() is called inside the prepared section. This
guarantees that nothing else will affect the creds until we've finished.
The calling of set_dumpable() has been moved into commit_creds().
Much of the functionality of set_user() has been moved into
commit_creds().
The get functions all simply access the data directly.
(8) security_task_prctl() and cap_task_prctl().
security_task_prctl() has been modified to return -ENOSYS if it doesn't
want to handle a function, or otherwise return the return value directly
rather than through an argument.
Additionally, cap_task_prctl() now prepares a new set of credentials, even
if it doesn't end up using it.
(9) Keyrings.
A number of changes have been made to the keyrings code:
(a) switch_uid_keyring(), copy_keys(), exit_keys() and suid_keys() have
all been dropped and built in to the credentials functions directly.
They may want separating out again later.
(b) key_alloc() and search_process_keyrings() now take a cred pointer
rather than a task pointer to specify the security context.
(c) copy_creds() gives a new thread within the same thread group a new
thread keyring if its parent had one, otherwise it discards the thread
keyring.
(d) The authorisation key now points directly to the credentials to extend
the search into rather pointing to the task that carries them.
(e) Installing thread, process or session keyrings causes a new set of
credentials to be created, even though it's not strictly necessary for
process or session keyrings (they're shared).
(10) Usermode helper.
The usermode helper code now carries a cred struct pointer in its
subprocess_info struct instead of a new session keyring pointer. This set
of credentials is derived from init_cred and installed on the new process
after it has been cloned.
call_usermodehelper_setup() allocates the new credentials and
call_usermodehelper_freeinfo() discards them if they haven't been used. A
special cred function (prepare_usermodeinfo_creds()) is provided
specifically for call_usermodehelper_setup() to call.
call_usermodehelper_setkeys() adjusts the credentials to sport the
supplied keyring as the new session keyring.
(11) SELinux.
SELinux has a number of changes, in addition to those to support the LSM
interface changes mentioned above:
(a) selinux_setprocattr() no longer does its check for whether the
current ptracer can access processes with the new SID inside the lock
that covers getting the ptracer's SID. Whilst this lock ensures that
the check is done with the ptracer pinned, the result is only valid
until the lock is released, so there's no point doing it inside the
lock.
(12) is_single_threaded().
This function has been extracted from selinux_setprocattr() and put into
a file of its own in the lib/ directory as join_session_keyring() now
wants to use it too.
The code in SELinux just checked to see whether a task shared mm_structs
with other tasks (CLONE_VM), but that isn't good enough. We really want
to know if they're part of the same thread group (CLONE_THREAD).
(13) nfsd.
The NFS server daemon now has to use the COW credentials to set the
credentials it is going to use. It really needs to pass the credentials
down to the functions it calls, but it can't do that until other patches
in this series have been applied.
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: James Morris <jmorris@namei.org>
Signed-off-by: James Morris <jmorris@namei.org>
2008-11-13 23:39:23 +00:00
|
|
|
tsec = new->security;
|
|
|
|
if (!strcmp(name, "exec")) {
|
2005-04-16 22:20:36 +00:00
|
|
|
tsec->exec_sid = sid;
|
CRED: Inaugurate COW credentials
Inaugurate copy-on-write credentials management. This uses RCU to manage the
credentials pointer in the task_struct with respect to accesses by other tasks.
A process may only modify its own credentials, and so does not need locking to
access or modify its own credentials.
A mutex (cred_replace_mutex) is added to the task_struct to control the effect
of PTRACE_ATTACHED on credential calculations, particularly with respect to
execve().
With this patch, the contents of an active credentials struct may not be
changed directly; rather a new set of credentials must be prepared, modified
and committed using something like the following sequence of events:
struct cred *new = prepare_creds();
int ret = blah(new);
if (ret < 0) {
abort_creds(new);
return ret;
}
return commit_creds(new);
There are some exceptions to this rule: the keyrings pointed to by the active
credentials may be instantiated - keyrings violate the COW rule as managing
COW keyrings is tricky, given that it is possible for a task to directly alter
the keys in a keyring in use by another task.
To help enforce this, various pointers to sets of credentials, such as those in
the task_struct, are declared const. The purpose of this is compile-time
discouragement of altering credentials through those pointers. Once a set of
credentials has been made public through one of these pointers, it may not be
modified, except under special circumstances:
(1) Its reference count may incremented and decremented.
(2) The keyrings to which it points may be modified, but not replaced.
The only safe way to modify anything else is to create a replacement and commit
using the functions described in Documentation/credentials.txt (which will be
added by a later patch).
This patch and the preceding patches have been tested with the LTP SELinux
testsuite.
This patch makes several logical sets of alteration:
(1) execve().
This now prepares and commits credentials in various places in the
security code rather than altering the current creds directly.
(2) Temporary credential overrides.
do_coredump() and sys_faccessat() now prepare their own credentials and
temporarily override the ones currently on the acting thread, whilst
preventing interference from other threads by holding cred_replace_mutex
on the thread being dumped.
This will be replaced in a future patch by something that hands down the
credentials directly to the functions being called, rather than altering
the task's objective credentials.
(3) LSM interface.
A number of functions have been changed, added or removed:
(*) security_capset_check(), ->capset_check()
(*) security_capset_set(), ->capset_set()
Removed in favour of security_capset().
(*) security_capset(), ->capset()
New. This is passed a pointer to the new creds, a pointer to the old
creds and the proposed capability sets. It should fill in the new
creds or return an error. All pointers, barring the pointer to the
new creds, are now const.
(*) security_bprm_apply_creds(), ->bprm_apply_creds()
Changed; now returns a value, which will cause the process to be
killed if it's an error.
(*) security_task_alloc(), ->task_alloc_security()
Removed in favour of security_prepare_creds().
(*) security_cred_free(), ->cred_free()
New. Free security data attached to cred->security.
(*) security_prepare_creds(), ->cred_prepare()
New. Duplicate any security data attached to cred->security.
(*) security_commit_creds(), ->cred_commit()
New. Apply any security effects for the upcoming installation of new
security by commit_creds().
(*) security_task_post_setuid(), ->task_post_setuid()
Removed in favour of security_task_fix_setuid().
(*) security_task_fix_setuid(), ->task_fix_setuid()
Fix up the proposed new credentials for setuid(). This is used by
cap_set_fix_setuid() to implicitly adjust capabilities in line with
setuid() changes. Changes are made to the new credentials, rather
than the task itself as in security_task_post_setuid().
(*) security_task_reparent_to_init(), ->task_reparent_to_init()
Removed. Instead the task being reparented to init is referred
directly to init's credentials.
NOTE! This results in the loss of some state: SELinux's osid no
longer records the sid of the thread that forked it.
(*) security_key_alloc(), ->key_alloc()
(*) security_key_permission(), ->key_permission()
Changed. These now take cred pointers rather than task pointers to
refer to the security context.
(4) sys_capset().
This has been simplified and uses less locking. The LSM functions it
calls have been merged.
(5) reparent_to_kthreadd().
This gives the current thread the same credentials as init by simply using
commit_thread() to point that way.
(6) __sigqueue_alloc() and switch_uid()
__sigqueue_alloc() can't stop the target task from changing its creds
beneath it, so this function gets a reference to the currently applicable
user_struct which it then passes into the sigqueue struct it returns if
successful.
switch_uid() is now called from commit_creds(), and possibly should be
folded into that. commit_creds() should take care of protecting
__sigqueue_alloc().
(7) [sg]et[ug]id() and co and [sg]et_current_groups.
The set functions now all use prepare_creds(), commit_creds() and
abort_creds() to build and check a new set of credentials before applying
it.
security_task_set[ug]id() is called inside the prepared section. This
guarantees that nothing else will affect the creds until we've finished.
The calling of set_dumpable() has been moved into commit_creds().
Much of the functionality of set_user() has been moved into
commit_creds().
The get functions all simply access the data directly.
(8) security_task_prctl() and cap_task_prctl().
security_task_prctl() has been modified to return -ENOSYS if it doesn't
want to handle a function, or otherwise return the return value directly
rather than through an argument.
Additionally, cap_task_prctl() now prepares a new set of credentials, even
if it doesn't end up using it.
(9) Keyrings.
A number of changes have been made to the keyrings code:
(a) switch_uid_keyring(), copy_keys(), exit_keys() and suid_keys() have
all been dropped and built in to the credentials functions directly.
They may want separating out again later.
(b) key_alloc() and search_process_keyrings() now take a cred pointer
rather than a task pointer to specify the security context.
(c) copy_creds() gives a new thread within the same thread group a new
thread keyring if its parent had one, otherwise it discards the thread
keyring.
(d) The authorisation key now points directly to the credentials to extend
the search into rather pointing to the task that carries them.
(e) Installing thread, process or session keyrings causes a new set of
credentials to be created, even though it's not strictly necessary for
process or session keyrings (they're shared).
(10) Usermode helper.
The usermode helper code now carries a cred struct pointer in its
subprocess_info struct instead of a new session keyring pointer. This set
of credentials is derived from init_cred and installed on the new process
after it has been cloned.
call_usermodehelper_setup() allocates the new credentials and
call_usermodehelper_freeinfo() discards them if they haven't been used. A
special cred function (prepare_usermodeinfo_creds()) is provided
specifically for call_usermodehelper_setup() to call.
call_usermodehelper_setkeys() adjusts the credentials to sport the
supplied keyring as the new session keyring.
(11) SELinux.
SELinux has a number of changes, in addition to those to support the LSM
interface changes mentioned above:
(a) selinux_setprocattr() no longer does its check for whether the
current ptracer can access processes with the new SID inside the lock
that covers getting the ptracer's SID. Whilst this lock ensures that
the check is done with the ptracer pinned, the result is only valid
until the lock is released, so there's no point doing it inside the
lock.
(12) is_single_threaded().
This function has been extracted from selinux_setprocattr() and put into
a file of its own in the lib/ directory as join_session_keyring() now
wants to use it too.
The code in SELinux just checked to see whether a task shared mm_structs
with other tasks (CLONE_VM), but that isn't good enough. We really want
to know if they're part of the same thread group (CLONE_THREAD).
(13) nfsd.
The NFS server daemon now has to use the COW credentials to set the
credentials it is going to use. It really needs to pass the credentials
down to the functions it calls, but it can't do that until other patches
in this series have been applied.
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: James Morris <jmorris@namei.org>
Signed-off-by: James Morris <jmorris@namei.org>
2008-11-13 23:39:23 +00:00
|
|
|
} else if (!strcmp(name, "fscreate")) {
|
2005-04-16 22:20:36 +00:00
|
|
|
tsec->create_sid = sid;
|
CRED: Inaugurate COW credentials
Inaugurate copy-on-write credentials management. This uses RCU to manage the
credentials pointer in the task_struct with respect to accesses by other tasks.
A process may only modify its own credentials, and so does not need locking to
access or modify its own credentials.
A mutex (cred_replace_mutex) is added to the task_struct to control the effect
of PTRACE_ATTACHED on credential calculations, particularly with respect to
execve().
With this patch, the contents of an active credentials struct may not be
changed directly; rather a new set of credentials must be prepared, modified
and committed using something like the following sequence of events:
struct cred *new = prepare_creds();
int ret = blah(new);
if (ret < 0) {
abort_creds(new);
return ret;
}
return commit_creds(new);
There are some exceptions to this rule: the keyrings pointed to by the active
credentials may be instantiated - keyrings violate the COW rule as managing
COW keyrings is tricky, given that it is possible for a task to directly alter
the keys in a keyring in use by another task.
To help enforce this, various pointers to sets of credentials, such as those in
the task_struct, are declared const. The purpose of this is compile-time
discouragement of altering credentials through those pointers. Once a set of
credentials has been made public through one of these pointers, it may not be
modified, except under special circumstances:
(1) Its reference count may incremented and decremented.
(2) The keyrings to which it points may be modified, but not replaced.
The only safe way to modify anything else is to create a replacement and commit
using the functions described in Documentation/credentials.txt (which will be
added by a later patch).
This patch and the preceding patches have been tested with the LTP SELinux
testsuite.
This patch makes several logical sets of alteration:
(1) execve().
This now prepares and commits credentials in various places in the
security code rather than altering the current creds directly.
(2) Temporary credential overrides.
do_coredump() and sys_faccessat() now prepare their own credentials and
temporarily override the ones currently on the acting thread, whilst
preventing interference from other threads by holding cred_replace_mutex
on the thread being dumped.
This will be replaced in a future patch by something that hands down the
credentials directly to the functions being called, rather than altering
the task's objective credentials.
(3) LSM interface.
A number of functions have been changed, added or removed:
(*) security_capset_check(), ->capset_check()
(*) security_capset_set(), ->capset_set()
Removed in favour of security_capset().
(*) security_capset(), ->capset()
New. This is passed a pointer to the new creds, a pointer to the old
creds and the proposed capability sets. It should fill in the new
creds or return an error. All pointers, barring the pointer to the
new creds, are now const.
(*) security_bprm_apply_creds(), ->bprm_apply_creds()
Changed; now returns a value, which will cause the process to be
killed if it's an error.
(*) security_task_alloc(), ->task_alloc_security()
Removed in favour of security_prepare_creds().
(*) security_cred_free(), ->cred_free()
New. Free security data attached to cred->security.
(*) security_prepare_creds(), ->cred_prepare()
New. Duplicate any security data attached to cred->security.
(*) security_commit_creds(), ->cred_commit()
New. Apply any security effects for the upcoming installation of new
security by commit_creds().
(*) security_task_post_setuid(), ->task_post_setuid()
Removed in favour of security_task_fix_setuid().
(*) security_task_fix_setuid(), ->task_fix_setuid()
Fix up the proposed new credentials for setuid(). This is used by
cap_set_fix_setuid() to implicitly adjust capabilities in line with
setuid() changes. Changes are made to the new credentials, rather
than the task itself as in security_task_post_setuid().
(*) security_task_reparent_to_init(), ->task_reparent_to_init()
Removed. Instead the task being reparented to init is referred
directly to init's credentials.
NOTE! This results in the loss of some state: SELinux's osid no
longer records the sid of the thread that forked it.
(*) security_key_alloc(), ->key_alloc()
(*) security_key_permission(), ->key_permission()
Changed. These now take cred pointers rather than task pointers to
refer to the security context.
(4) sys_capset().
This has been simplified and uses less locking. The LSM functions it
calls have been merged.
(5) reparent_to_kthreadd().
This gives the current thread the same credentials as init by simply using
commit_thread() to point that way.
(6) __sigqueue_alloc() and switch_uid()
__sigqueue_alloc() can't stop the target task from changing its creds
beneath it, so this function gets a reference to the currently applicable
user_struct which it then passes into the sigqueue struct it returns if
successful.
switch_uid() is now called from commit_creds(), and possibly should be
folded into that. commit_creds() should take care of protecting
__sigqueue_alloc().
(7) [sg]et[ug]id() and co and [sg]et_current_groups.
The set functions now all use prepare_creds(), commit_creds() and
abort_creds() to build and check a new set of credentials before applying
it.
security_task_set[ug]id() is called inside the prepared section. This
guarantees that nothing else will affect the creds until we've finished.
The calling of set_dumpable() has been moved into commit_creds().
Much of the functionality of set_user() has been moved into
commit_creds().
The get functions all simply access the data directly.
(8) security_task_prctl() and cap_task_prctl().
security_task_prctl() has been modified to return -ENOSYS if it doesn't
want to handle a function, or otherwise return the return value directly
rather than through an argument.
Additionally, cap_task_prctl() now prepares a new set of credentials, even
if it doesn't end up using it.
(9) Keyrings.
A number of changes have been made to the keyrings code:
(a) switch_uid_keyring(), copy_keys(), exit_keys() and suid_keys() have
all been dropped and built in to the credentials functions directly.
They may want separating out again later.
(b) key_alloc() and search_process_keyrings() now take a cred pointer
rather than a task pointer to specify the security context.
(c) copy_creds() gives a new thread within the same thread group a new
thread keyring if its parent had one, otherwise it discards the thread
keyring.
(d) The authorisation key now points directly to the credentials to extend
the search into rather pointing to the task that carries them.
(e) Installing thread, process or session keyrings causes a new set of
credentials to be created, even though it's not strictly necessary for
process or session keyrings (they're shared).
(10) Usermode helper.
The usermode helper code now carries a cred struct pointer in its
subprocess_info struct instead of a new session keyring pointer. This set
of credentials is derived from init_cred and installed on the new process
after it has been cloned.
call_usermodehelper_setup() allocates the new credentials and
call_usermodehelper_freeinfo() discards them if they haven't been used. A
special cred function (prepare_usermodeinfo_creds()) is provided
specifically for call_usermodehelper_setup() to call.
call_usermodehelper_setkeys() adjusts the credentials to sport the
supplied keyring as the new session keyring.
(11) SELinux.
SELinux has a number of changes, in addition to those to support the LSM
interface changes mentioned above:
(a) selinux_setprocattr() no longer does its check for whether the
current ptracer can access processes with the new SID inside the lock
that covers getting the ptracer's SID. Whilst this lock ensures that
the check is done with the ptracer pinned, the result is only valid
until the lock is released, so there's no point doing it inside the
lock.
(12) is_single_threaded().
This function has been extracted from selinux_setprocattr() and put into
a file of its own in the lib/ directory as join_session_keyring() now
wants to use it too.
The code in SELinux just checked to see whether a task shared mm_structs
with other tasks (CLONE_VM), but that isn't good enough. We really want
to know if they're part of the same thread group (CLONE_THREAD).
(13) nfsd.
The NFS server daemon now has to use the COW credentials to set the
credentials it is going to use. It really needs to pass the credentials
down to the functions it calls, but it can't do that until other patches
in this series have been applied.
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: James Morris <jmorris@namei.org>
Signed-off-by: James Morris <jmorris@namei.org>
2008-11-13 23:39:23 +00:00
|
|
|
} else if (!strcmp(name, "keycreate")) {
|
2006-06-26 07:24:57 +00:00
|
|
|
error = may_create_key(sid, p);
|
|
|
|
if (error)
|
CRED: Inaugurate COW credentials
Inaugurate copy-on-write credentials management. This uses RCU to manage the
credentials pointer in the task_struct with respect to accesses by other tasks.
A process may only modify its own credentials, and so does not need locking to
access or modify its own credentials.
A mutex (cred_replace_mutex) is added to the task_struct to control the effect
of PTRACE_ATTACHED on credential calculations, particularly with respect to
execve().
With this patch, the contents of an active credentials struct may not be
changed directly; rather a new set of credentials must be prepared, modified
and committed using something like the following sequence of events:
struct cred *new = prepare_creds();
int ret = blah(new);
if (ret < 0) {
abort_creds(new);
return ret;
}
return commit_creds(new);
There are some exceptions to this rule: the keyrings pointed to by the active
credentials may be instantiated - keyrings violate the COW rule as managing
COW keyrings is tricky, given that it is possible for a task to directly alter
the keys in a keyring in use by another task.
To help enforce this, various pointers to sets of credentials, such as those in
the task_struct, are declared const. The purpose of this is compile-time
discouragement of altering credentials through those pointers. Once a set of
credentials has been made public through one of these pointers, it may not be
modified, except under special circumstances:
(1) Its reference count may incremented and decremented.
(2) The keyrings to which it points may be modified, but not replaced.
The only safe way to modify anything else is to create a replacement and commit
using the functions described in Documentation/credentials.txt (which will be
added by a later patch).
This patch and the preceding patches have been tested with the LTP SELinux
testsuite.
This patch makes several logical sets of alteration:
(1) execve().
This now prepares and commits credentials in various places in the
security code rather than altering the current creds directly.
(2) Temporary credential overrides.
do_coredump() and sys_faccessat() now prepare their own credentials and
temporarily override the ones currently on the acting thread, whilst
preventing interference from other threads by holding cred_replace_mutex
on the thread being dumped.
This will be replaced in a future patch by something that hands down the
credentials directly to the functions being called, rather than altering
the task's objective credentials.
(3) LSM interface.
A number of functions have been changed, added or removed:
(*) security_capset_check(), ->capset_check()
(*) security_capset_set(), ->capset_set()
Removed in favour of security_capset().
(*) security_capset(), ->capset()
New. This is passed a pointer to the new creds, a pointer to the old
creds and the proposed capability sets. It should fill in the new
creds or return an error. All pointers, barring the pointer to the
new creds, are now const.
(*) security_bprm_apply_creds(), ->bprm_apply_creds()
Changed; now returns a value, which will cause the process to be
killed if it's an error.
(*) security_task_alloc(), ->task_alloc_security()
Removed in favour of security_prepare_creds().
(*) security_cred_free(), ->cred_free()
New. Free security data attached to cred->security.
(*) security_prepare_creds(), ->cred_prepare()
New. Duplicate any security data attached to cred->security.
(*) security_commit_creds(), ->cred_commit()
New. Apply any security effects for the upcoming installation of new
security by commit_creds().
(*) security_task_post_setuid(), ->task_post_setuid()
Removed in favour of security_task_fix_setuid().
(*) security_task_fix_setuid(), ->task_fix_setuid()
Fix up the proposed new credentials for setuid(). This is used by
cap_set_fix_setuid() to implicitly adjust capabilities in line with
setuid() changes. Changes are made to the new credentials, rather
than the task itself as in security_task_post_setuid().
(*) security_task_reparent_to_init(), ->task_reparent_to_init()
Removed. Instead the task being reparented to init is referred
directly to init's credentials.
NOTE! This results in the loss of some state: SELinux's osid no
longer records the sid of the thread that forked it.
(*) security_key_alloc(), ->key_alloc()
(*) security_key_permission(), ->key_permission()
Changed. These now take cred pointers rather than task pointers to
refer to the security context.
(4) sys_capset().
This has been simplified and uses less locking. The LSM functions it
calls have been merged.
(5) reparent_to_kthreadd().
This gives the current thread the same credentials as init by simply using
commit_thread() to point that way.
(6) __sigqueue_alloc() and switch_uid()
__sigqueue_alloc() can't stop the target task from changing its creds
beneath it, so this function gets a reference to the currently applicable
user_struct which it then passes into the sigqueue struct it returns if
successful.
switch_uid() is now called from commit_creds(), and possibly should be
folded into that. commit_creds() should take care of protecting
__sigqueue_alloc().
(7) [sg]et[ug]id() and co and [sg]et_current_groups.
The set functions now all use prepare_creds(), commit_creds() and
abort_creds() to build and check a new set of credentials before applying
it.
security_task_set[ug]id() is called inside the prepared section. This
guarantees that nothing else will affect the creds until we've finished.
The calling of set_dumpable() has been moved into commit_creds().
Much of the functionality of set_user() has been moved into
commit_creds().
The get functions all simply access the data directly.
(8) security_task_prctl() and cap_task_prctl().
security_task_prctl() has been modified to return -ENOSYS if it doesn't
want to handle a function, or otherwise return the return value directly
rather than through an argument.
Additionally, cap_task_prctl() now prepares a new set of credentials, even
if it doesn't end up using it.
(9) Keyrings.
A number of changes have been made to the keyrings code:
(a) switch_uid_keyring(), copy_keys(), exit_keys() and suid_keys() have
all been dropped and built in to the credentials functions directly.
They may want separating out again later.
(b) key_alloc() and search_process_keyrings() now take a cred pointer
rather than a task pointer to specify the security context.
(c) copy_creds() gives a new thread within the same thread group a new
thread keyring if its parent had one, otherwise it discards the thread
keyring.
(d) The authorisation key now points directly to the credentials to extend
the search into rather pointing to the task that carries them.
(e) Installing thread, process or session keyrings causes a new set of
credentials to be created, even though it's not strictly necessary for
process or session keyrings (they're shared).
(10) Usermode helper.
The usermode helper code now carries a cred struct pointer in its
subprocess_info struct instead of a new session keyring pointer. This set
of credentials is derived from init_cred and installed on the new process
after it has been cloned.
call_usermodehelper_setup() allocates the new credentials and
call_usermodehelper_freeinfo() discards them if they haven't been used. A
special cred function (prepare_usermodeinfo_creds()) is provided
specifically for call_usermodehelper_setup() to call.
call_usermodehelper_setkeys() adjusts the credentials to sport the
supplied keyring as the new session keyring.
(11) SELinux.
SELinux has a number of changes, in addition to those to support the LSM
interface changes mentioned above:
(a) selinux_setprocattr() no longer does its check for whether the
current ptracer can access processes with the new SID inside the lock
that covers getting the ptracer's SID. Whilst this lock ensures that
the check is done with the ptracer pinned, the result is only valid
until the lock is released, so there's no point doing it inside the
lock.
(12) is_single_threaded().
This function has been extracted from selinux_setprocattr() and put into
a file of its own in the lib/ directory as join_session_keyring() now
wants to use it too.
The code in SELinux just checked to see whether a task shared mm_structs
with other tasks (CLONE_VM), but that isn't good enough. We really want
to know if they're part of the same thread group (CLONE_THREAD).
(13) nfsd.
The NFS server daemon now has to use the COW credentials to set the
credentials it is going to use. It really needs to pass the credentials
down to the functions it calls, but it can't do that until other patches
in this series have been applied.
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: James Morris <jmorris@namei.org>
Signed-off-by: James Morris <jmorris@namei.org>
2008-11-13 23:39:23 +00:00
|
|
|
goto abort_change;
|
2006-06-26 07:24:57 +00:00
|
|
|
tsec->keycreate_sid = sid;
|
CRED: Inaugurate COW credentials
Inaugurate copy-on-write credentials management. This uses RCU to manage the
credentials pointer in the task_struct with respect to accesses by other tasks.
A process may only modify its own credentials, and so does not need locking to
access or modify its own credentials.
A mutex (cred_replace_mutex) is added to the task_struct to control the effect
of PTRACE_ATTACHED on credential calculations, particularly with respect to
execve().
With this patch, the contents of an active credentials struct may not be
changed directly; rather a new set of credentials must be prepared, modified
and committed using something like the following sequence of events:
struct cred *new = prepare_creds();
int ret = blah(new);
if (ret < 0) {
abort_creds(new);
return ret;
}
return commit_creds(new);
There are some exceptions to this rule: the keyrings pointed to by the active
credentials may be instantiated - keyrings violate the COW rule as managing
COW keyrings is tricky, given that it is possible for a task to directly alter
the keys in a keyring in use by another task.
To help enforce this, various pointers to sets of credentials, such as those in
the task_struct, are declared const. The purpose of this is compile-time
discouragement of altering credentials through those pointers. Once a set of
credentials has been made public through one of these pointers, it may not be
modified, except under special circumstances:
(1) Its reference count may incremented and decremented.
(2) The keyrings to which it points may be modified, but not replaced.
The only safe way to modify anything else is to create a replacement and commit
using the functions described in Documentation/credentials.txt (which will be
added by a later patch).
This patch and the preceding patches have been tested with the LTP SELinux
testsuite.
This patch makes several logical sets of alteration:
(1) execve().
This now prepares and commits credentials in various places in the
security code rather than altering the current creds directly.
(2) Temporary credential overrides.
do_coredump() and sys_faccessat() now prepare their own credentials and
temporarily override the ones currently on the acting thread, whilst
preventing interference from other threads by holding cred_replace_mutex
on the thread being dumped.
This will be replaced in a future patch by something that hands down the
credentials directly to the functions being called, rather than altering
the task's objective credentials.
(3) LSM interface.
A number of functions have been changed, added or removed:
(*) security_capset_check(), ->capset_check()
(*) security_capset_set(), ->capset_set()
Removed in favour of security_capset().
(*) security_capset(), ->capset()
New. This is passed a pointer to the new creds, a pointer to the old
creds and the proposed capability sets. It should fill in the new
creds or return an error. All pointers, barring the pointer to the
new creds, are now const.
(*) security_bprm_apply_creds(), ->bprm_apply_creds()
Changed; now returns a value, which will cause the process to be
killed if it's an error.
(*) security_task_alloc(), ->task_alloc_security()
Removed in favour of security_prepare_creds().
(*) security_cred_free(), ->cred_free()
New. Free security data attached to cred->security.
(*) security_prepare_creds(), ->cred_prepare()
New. Duplicate any security data attached to cred->security.
(*) security_commit_creds(), ->cred_commit()
New. Apply any security effects for the upcoming installation of new
security by commit_creds().
(*) security_task_post_setuid(), ->task_post_setuid()
Removed in favour of security_task_fix_setuid().
(*) security_task_fix_setuid(), ->task_fix_setuid()
Fix up the proposed new credentials for setuid(). This is used by
cap_set_fix_setuid() to implicitly adjust capabilities in line with
setuid() changes. Changes are made to the new credentials, rather
than the task itself as in security_task_post_setuid().
(*) security_task_reparent_to_init(), ->task_reparent_to_init()
Removed. Instead the task being reparented to init is referred
directly to init's credentials.
NOTE! This results in the loss of some state: SELinux's osid no
longer records the sid of the thread that forked it.
(*) security_key_alloc(), ->key_alloc()
(*) security_key_permission(), ->key_permission()
Changed. These now take cred pointers rather than task pointers to
refer to the security context.
(4) sys_capset().
This has been simplified and uses less locking. The LSM functions it
calls have been merged.
(5) reparent_to_kthreadd().
This gives the current thread the same credentials as init by simply using
commit_thread() to point that way.
(6) __sigqueue_alloc() and switch_uid()
__sigqueue_alloc() can't stop the target task from changing its creds
beneath it, so this function gets a reference to the currently applicable
user_struct which it then passes into the sigqueue struct it returns if
successful.
switch_uid() is now called from commit_creds(), and possibly should be
folded into that. commit_creds() should take care of protecting
__sigqueue_alloc().
(7) [sg]et[ug]id() and co and [sg]et_current_groups.
The set functions now all use prepare_creds(), commit_creds() and
abort_creds() to build and check a new set of credentials before applying
it.
security_task_set[ug]id() is called inside the prepared section. This
guarantees that nothing else will affect the creds until we've finished.
The calling of set_dumpable() has been moved into commit_creds().
Much of the functionality of set_user() has been moved into
commit_creds().
The get functions all simply access the data directly.
(8) security_task_prctl() and cap_task_prctl().
security_task_prctl() has been modified to return -ENOSYS if it doesn't
want to handle a function, or otherwise return the return value directly
rather than through an argument.
Additionally, cap_task_prctl() now prepares a new set of credentials, even
if it doesn't end up using it.
(9) Keyrings.
A number of changes have been made to the keyrings code:
(a) switch_uid_keyring(), copy_keys(), exit_keys() and suid_keys() have
all been dropped and built in to the credentials functions directly.
They may want separating out again later.
(b) key_alloc() and search_process_keyrings() now take a cred pointer
rather than a task pointer to specify the security context.
(c) copy_creds() gives a new thread within the same thread group a new
thread keyring if its parent had one, otherwise it discards the thread
keyring.
(d) The authorisation key now points directly to the credentials to extend
the search into rather pointing to the task that carries them.
(e) Installing thread, process or session keyrings causes a new set of
credentials to be created, even though it's not strictly necessary for
process or session keyrings (they're shared).
(10) Usermode helper.
The usermode helper code now carries a cred struct pointer in its
subprocess_info struct instead of a new session keyring pointer. This set
of credentials is derived from init_cred and installed on the new process
after it has been cloned.
call_usermodehelper_setup() allocates the new credentials and
call_usermodehelper_freeinfo() discards them if they haven't been used. A
special cred function (prepare_usermodeinfo_creds()) is provided
specifically for call_usermodehelper_setup() to call.
call_usermodehelper_setkeys() adjusts the credentials to sport the
supplied keyring as the new session keyring.
(11) SELinux.
SELinux has a number of changes, in addition to those to support the LSM
interface changes mentioned above:
(a) selinux_setprocattr() no longer does its check for whether the
current ptracer can access processes with the new SID inside the lock
that covers getting the ptracer's SID. Whilst this lock ensures that
the check is done with the ptracer pinned, the result is only valid
until the lock is released, so there's no point doing it inside the
lock.
(12) is_single_threaded().
This function has been extracted from selinux_setprocattr() and put into
a file of its own in the lib/ directory as join_session_keyring() now
wants to use it too.
The code in SELinux just checked to see whether a task shared mm_structs
with other tasks (CLONE_VM), but that isn't good enough. We really want
to know if they're part of the same thread group (CLONE_THREAD).
(13) nfsd.
The NFS server daemon now has to use the COW credentials to set the
credentials it is going to use. It really needs to pass the credentials
down to the functions it calls, but it can't do that until other patches
in this series have been applied.
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: James Morris <jmorris@namei.org>
Signed-off-by: James Morris <jmorris@namei.org>
2008-11-13 23:39:23 +00:00
|
|
|
} else if (!strcmp(name, "sockcreate")) {
|
2006-06-26 07:26:03 +00:00
|
|
|
tsec->sockcreate_sid = sid;
|
CRED: Inaugurate COW credentials
Inaugurate copy-on-write credentials management. This uses RCU to manage the
credentials pointer in the task_struct with respect to accesses by other tasks.
A process may only modify its own credentials, and so does not need locking to
access or modify its own credentials.
A mutex (cred_replace_mutex) is added to the task_struct to control the effect
of PTRACE_ATTACHED on credential calculations, particularly with respect to
execve().
With this patch, the contents of an active credentials struct may not be
changed directly; rather a new set of credentials must be prepared, modified
and committed using something like the following sequence of events:
struct cred *new = prepare_creds();
int ret = blah(new);
if (ret < 0) {
abort_creds(new);
return ret;
}
return commit_creds(new);
There are some exceptions to this rule: the keyrings pointed to by the active
credentials may be instantiated - keyrings violate the COW rule as managing
COW keyrings is tricky, given that it is possible for a task to directly alter
the keys in a keyring in use by another task.
To help enforce this, various pointers to sets of credentials, such as those in
the task_struct, are declared const. The purpose of this is compile-time
discouragement of altering credentials through those pointers. Once a set of
credentials has been made public through one of these pointers, it may not be
modified, except under special circumstances:
(1) Its reference count may incremented and decremented.
(2) The keyrings to which it points may be modified, but not replaced.
The only safe way to modify anything else is to create a replacement and commit
using the functions described in Documentation/credentials.txt (which will be
added by a later patch).
This patch and the preceding patches have been tested with the LTP SELinux
testsuite.
This patch makes several logical sets of alteration:
(1) execve().
This now prepares and commits credentials in various places in the
security code rather than altering the current creds directly.
(2) Temporary credential overrides.
do_coredump() and sys_faccessat() now prepare their own credentials and
temporarily override the ones currently on the acting thread, whilst
preventing interference from other threads by holding cred_replace_mutex
on the thread being dumped.
This will be replaced in a future patch by something that hands down the
credentials directly to the functions being called, rather than altering
the task's objective credentials.
(3) LSM interface.
A number of functions have been changed, added or removed:
(*) security_capset_check(), ->capset_check()
(*) security_capset_set(), ->capset_set()
Removed in favour of security_capset().
(*) security_capset(), ->capset()
New. This is passed a pointer to the new creds, a pointer to the old
creds and the proposed capability sets. It should fill in the new
creds or return an error. All pointers, barring the pointer to the
new creds, are now const.
(*) security_bprm_apply_creds(), ->bprm_apply_creds()
Changed; now returns a value, which will cause the process to be
killed if it's an error.
(*) security_task_alloc(), ->task_alloc_security()
Removed in favour of security_prepare_creds().
(*) security_cred_free(), ->cred_free()
New. Free security data attached to cred->security.
(*) security_prepare_creds(), ->cred_prepare()
New. Duplicate any security data attached to cred->security.
(*) security_commit_creds(), ->cred_commit()
New. Apply any security effects for the upcoming installation of new
security by commit_creds().
(*) security_task_post_setuid(), ->task_post_setuid()
Removed in favour of security_task_fix_setuid().
(*) security_task_fix_setuid(), ->task_fix_setuid()
Fix up the proposed new credentials for setuid(). This is used by
cap_set_fix_setuid() to implicitly adjust capabilities in line with
setuid() changes. Changes are made to the new credentials, rather
than the task itself as in security_task_post_setuid().
(*) security_task_reparent_to_init(), ->task_reparent_to_init()
Removed. Instead the task being reparented to init is referred
directly to init's credentials.
NOTE! This results in the loss of some state: SELinux's osid no
longer records the sid of the thread that forked it.
(*) security_key_alloc(), ->key_alloc()
(*) security_key_permission(), ->key_permission()
Changed. These now take cred pointers rather than task pointers to
refer to the security context.
(4) sys_capset().
This has been simplified and uses less locking. The LSM functions it
calls have been merged.
(5) reparent_to_kthreadd().
This gives the current thread the same credentials as init by simply using
commit_thread() to point that way.
(6) __sigqueue_alloc() and switch_uid()
__sigqueue_alloc() can't stop the target task from changing its creds
beneath it, so this function gets a reference to the currently applicable
user_struct which it then passes into the sigqueue struct it returns if
successful.
switch_uid() is now called from commit_creds(), and possibly should be
folded into that. commit_creds() should take care of protecting
__sigqueue_alloc().
(7) [sg]et[ug]id() and co and [sg]et_current_groups.
The set functions now all use prepare_creds(), commit_creds() and
abort_creds() to build and check a new set of credentials before applying
it.
security_task_set[ug]id() is called inside the prepared section. This
guarantees that nothing else will affect the creds until we've finished.
The calling of set_dumpable() has been moved into commit_creds().
Much of the functionality of set_user() has been moved into
commit_creds().
The get functions all simply access the data directly.
(8) security_task_prctl() and cap_task_prctl().
security_task_prctl() has been modified to return -ENOSYS if it doesn't
want to handle a function, or otherwise return the return value directly
rather than through an argument.
Additionally, cap_task_prctl() now prepares a new set of credentials, even
if it doesn't end up using it.
(9) Keyrings.
A number of changes have been made to the keyrings code:
(a) switch_uid_keyring(), copy_keys(), exit_keys() and suid_keys() have
all been dropped and built in to the credentials functions directly.
They may want separating out again later.
(b) key_alloc() and search_process_keyrings() now take a cred pointer
rather than a task pointer to specify the security context.
(c) copy_creds() gives a new thread within the same thread group a new
thread keyring if its parent had one, otherwise it discards the thread
keyring.
(d) The authorisation key now points directly to the credentials to extend
the search into rather pointing to the task that carries them.
(e) Installing thread, process or session keyrings causes a new set of
credentials to be created, even though it's not strictly necessary for
process or session keyrings (they're shared).
(10) Usermode helper.
The usermode helper code now carries a cred struct pointer in its
subprocess_info struct instead of a new session keyring pointer. This set
of credentials is derived from init_cred and installed on the new process
after it has been cloned.
call_usermodehelper_setup() allocates the new credentials and
call_usermodehelper_freeinfo() discards them if they haven't been used. A
special cred function (prepare_usermodeinfo_creds()) is provided
specifically for call_usermodehelper_setup() to call.
call_usermodehelper_setkeys() adjusts the credentials to sport the
supplied keyring as the new session keyring.
(11) SELinux.
SELinux has a number of changes, in addition to those to support the LSM
interface changes mentioned above:
(a) selinux_setprocattr() no longer does its check for whether the
current ptracer can access processes with the new SID inside the lock
that covers getting the ptracer's SID. Whilst this lock ensures that
the check is done with the ptracer pinned, the result is only valid
until the lock is released, so there's no point doing it inside the
lock.
(12) is_single_threaded().
This function has been extracted from selinux_setprocattr() and put into
a file of its own in the lib/ directory as join_session_keyring() now
wants to use it too.
The code in SELinux just checked to see whether a task shared mm_structs
with other tasks (CLONE_VM), but that isn't good enough. We really want
to know if they're part of the same thread group (CLONE_THREAD).
(13) nfsd.
The NFS server daemon now has to use the COW credentials to set the
credentials it is going to use. It really needs to pass the credentials
down to the functions it calls, but it can't do that until other patches
in this series have been applied.
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: James Morris <jmorris@namei.org>
Signed-off-by: James Morris <jmorris@namei.org>
2008-11-13 23:39:23 +00:00
|
|
|
} else if (!strcmp(name, "current")) {
|
|
|
|
error = -EINVAL;
|
2005-04-16 22:20:36 +00:00
|
|
|
if (sid == 0)
|
CRED: Inaugurate COW credentials
Inaugurate copy-on-write credentials management. This uses RCU to manage the
credentials pointer in the task_struct with respect to accesses by other tasks.
A process may only modify its own credentials, and so does not need locking to
access or modify its own credentials.
A mutex (cred_replace_mutex) is added to the task_struct to control the effect
of PTRACE_ATTACHED on credential calculations, particularly with respect to
execve().
With this patch, the contents of an active credentials struct may not be
changed directly; rather a new set of credentials must be prepared, modified
and committed using something like the following sequence of events:
struct cred *new = prepare_creds();
int ret = blah(new);
if (ret < 0) {
abort_creds(new);
return ret;
}
return commit_creds(new);
There are some exceptions to this rule: the keyrings pointed to by the active
credentials may be instantiated - keyrings violate the COW rule as managing
COW keyrings is tricky, given that it is possible for a task to directly alter
the keys in a keyring in use by another task.
To help enforce this, various pointers to sets of credentials, such as those in
the task_struct, are declared const. The purpose of this is compile-time
discouragement of altering credentials through those pointers. Once a set of
credentials has been made public through one of these pointers, it may not be
modified, except under special circumstances:
(1) Its reference count may incremented and decremented.
(2) The keyrings to which it points may be modified, but not replaced.
The only safe way to modify anything else is to create a replacement and commit
using the functions described in Documentation/credentials.txt (which will be
added by a later patch).
This patch and the preceding patches have been tested with the LTP SELinux
testsuite.
This patch makes several logical sets of alteration:
(1) execve().
This now prepares and commits credentials in various places in the
security code rather than altering the current creds directly.
(2) Temporary credential overrides.
do_coredump() and sys_faccessat() now prepare their own credentials and
temporarily override the ones currently on the acting thread, whilst
preventing interference from other threads by holding cred_replace_mutex
on the thread being dumped.
This will be replaced in a future patch by something that hands down the
credentials directly to the functions being called, rather than altering
the task's objective credentials.
(3) LSM interface.
A number of functions have been changed, added or removed:
(*) security_capset_check(), ->capset_check()
(*) security_capset_set(), ->capset_set()
Removed in favour of security_capset().
(*) security_capset(), ->capset()
New. This is passed a pointer to the new creds, a pointer to the old
creds and the proposed capability sets. It should fill in the new
creds or return an error. All pointers, barring the pointer to the
new creds, are now const.
(*) security_bprm_apply_creds(), ->bprm_apply_creds()
Changed; now returns a value, which will cause the process to be
killed if it's an error.
(*) security_task_alloc(), ->task_alloc_security()
Removed in favour of security_prepare_creds().
(*) security_cred_free(), ->cred_free()
New. Free security data attached to cred->security.
(*) security_prepare_creds(), ->cred_prepare()
New. Duplicate any security data attached to cred->security.
(*) security_commit_creds(), ->cred_commit()
New. Apply any security effects for the upcoming installation of new
security by commit_creds().
(*) security_task_post_setuid(), ->task_post_setuid()
Removed in favour of security_task_fix_setuid().
(*) security_task_fix_setuid(), ->task_fix_setuid()
Fix up the proposed new credentials for setuid(). This is used by
cap_set_fix_setuid() to implicitly adjust capabilities in line with
setuid() changes. Changes are made to the new credentials, rather
than the task itself as in security_task_post_setuid().
(*) security_task_reparent_to_init(), ->task_reparent_to_init()
Removed. Instead the task being reparented to init is referred
directly to init's credentials.
NOTE! This results in the loss of some state: SELinux's osid no
longer records the sid of the thread that forked it.
(*) security_key_alloc(), ->key_alloc()
(*) security_key_permission(), ->key_permission()
Changed. These now take cred pointers rather than task pointers to
refer to the security context.
(4) sys_capset().
This has been simplified and uses less locking. The LSM functions it
calls have been merged.
(5) reparent_to_kthreadd().
This gives the current thread the same credentials as init by simply using
commit_thread() to point that way.
(6) __sigqueue_alloc() and switch_uid()
__sigqueue_alloc() can't stop the target task from changing its creds
beneath it, so this function gets a reference to the currently applicable
user_struct which it then passes into the sigqueue struct it returns if
successful.
switch_uid() is now called from commit_creds(), and possibly should be
folded into that. commit_creds() should take care of protecting
__sigqueue_alloc().
(7) [sg]et[ug]id() and co and [sg]et_current_groups.
The set functions now all use prepare_creds(), commit_creds() and
abort_creds() to build and check a new set of credentials before applying
it.
security_task_set[ug]id() is called inside the prepared section. This
guarantees that nothing else will affect the creds until we've finished.
The calling of set_dumpable() has been moved into commit_creds().
Much of the functionality of set_user() has been moved into
commit_creds().
The get functions all simply access the data directly.
(8) security_task_prctl() and cap_task_prctl().
security_task_prctl() has been modified to return -ENOSYS if it doesn't
want to handle a function, or otherwise return the return value directly
rather than through an argument.
Additionally, cap_task_prctl() now prepares a new set of credentials, even
if it doesn't end up using it.
(9) Keyrings.
A number of changes have been made to the keyrings code:
(a) switch_uid_keyring(), copy_keys(), exit_keys() and suid_keys() have
all been dropped and built in to the credentials functions directly.
They may want separating out again later.
(b) key_alloc() and search_process_keyrings() now take a cred pointer
rather than a task pointer to specify the security context.
(c) copy_creds() gives a new thread within the same thread group a new
thread keyring if its parent had one, otherwise it discards the thread
keyring.
(d) The authorisation key now points directly to the credentials to extend
the search into rather pointing to the task that carries them.
(e) Installing thread, process or session keyrings causes a new set of
credentials to be created, even though it's not strictly necessary for
process or session keyrings (they're shared).
(10) Usermode helper.
The usermode helper code now carries a cred struct pointer in its
subprocess_info struct instead of a new session keyring pointer. This set
of credentials is derived from init_cred and installed on the new process
after it has been cloned.
call_usermodehelper_setup() allocates the new credentials and
call_usermodehelper_freeinfo() discards them if they haven't been used. A
special cred function (prepare_usermodeinfo_creds()) is provided
specifically for call_usermodehelper_setup() to call.
call_usermodehelper_setkeys() adjusts the credentials to sport the
supplied keyring as the new session keyring.
(11) SELinux.
SELinux has a number of changes, in addition to those to support the LSM
interface changes mentioned above:
(a) selinux_setprocattr() no longer does its check for whether the
current ptracer can access processes with the new SID inside the lock
that covers getting the ptracer's SID. Whilst this lock ensures that
the check is done with the ptracer pinned, the result is only valid
until the lock is released, so there's no point doing it inside the
lock.
(12) is_single_threaded().
This function has been extracted from selinux_setprocattr() and put into
a file of its own in the lib/ directory as join_session_keyring() now
wants to use it too.
The code in SELinux just checked to see whether a task shared mm_structs
with other tasks (CLONE_VM), but that isn't good enough. We really want
to know if they're part of the same thread group (CLONE_THREAD).
(13) nfsd.
The NFS server daemon now has to use the COW credentials to set the
credentials it is going to use. It really needs to pass the credentials
down to the functions it calls, but it can't do that until other patches
in this series have been applied.
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: James Morris <jmorris@namei.org>
Signed-off-by: James Morris <jmorris@namei.org>
2008-11-13 23:39:23 +00:00
|
|
|
goto abort_change;
|
|
|
|
|
|
|
|
/* Only allow single threaded processes to change context */
|
|
|
|
error = -EPERM;
|
2009-07-10 01:48:23 +00:00
|
|
|
if (!current_is_single_threaded()) {
|
CRED: Inaugurate COW credentials
Inaugurate copy-on-write credentials management. This uses RCU to manage the
credentials pointer in the task_struct with respect to accesses by other tasks.
A process may only modify its own credentials, and so does not need locking to
access or modify its own credentials.
A mutex (cred_replace_mutex) is added to the task_struct to control the effect
of PTRACE_ATTACHED on credential calculations, particularly with respect to
execve().
With this patch, the contents of an active credentials struct may not be
changed directly; rather a new set of credentials must be prepared, modified
and committed using something like the following sequence of events:
struct cred *new = prepare_creds();
int ret = blah(new);
if (ret < 0) {
abort_creds(new);
return ret;
}
return commit_creds(new);
There are some exceptions to this rule: the keyrings pointed to by the active
credentials may be instantiated - keyrings violate the COW rule as managing
COW keyrings is tricky, given that it is possible for a task to directly alter
the keys in a keyring in use by another task.
To help enforce this, various pointers to sets of credentials, such as those in
the task_struct, are declared const. The purpose of this is compile-time
discouragement of altering credentials through those pointers. Once a set of
credentials has been made public through one of these pointers, it may not be
modified, except under special circumstances:
(1) Its reference count may incremented and decremented.
(2) The keyrings to which it points may be modified, but not replaced.
The only safe way to modify anything else is to create a replacement and commit
using the functions described in Documentation/credentials.txt (which will be
added by a later patch).
This patch and the preceding patches have been tested with the LTP SELinux
testsuite.
This patch makes several logical sets of alteration:
(1) execve().
This now prepares and commits credentials in various places in the
security code rather than altering the current creds directly.
(2) Temporary credential overrides.
do_coredump() and sys_faccessat() now prepare their own credentials and
temporarily override the ones currently on the acting thread, whilst
preventing interference from other threads by holding cred_replace_mutex
on the thread being dumped.
This will be replaced in a future patch by something that hands down the
credentials directly to the functions being called, rather than altering
the task's objective credentials.
(3) LSM interface.
A number of functions have been changed, added or removed:
(*) security_capset_check(), ->capset_check()
(*) security_capset_set(), ->capset_set()
Removed in favour of security_capset().
(*) security_capset(), ->capset()
New. This is passed a pointer to the new creds, a pointer to the old
creds and the proposed capability sets. It should fill in the new
creds or return an error. All pointers, barring the pointer to the
new creds, are now const.
(*) security_bprm_apply_creds(), ->bprm_apply_creds()
Changed; now returns a value, which will cause the process to be
killed if it's an error.
(*) security_task_alloc(), ->task_alloc_security()
Removed in favour of security_prepare_creds().
(*) security_cred_free(), ->cred_free()
New. Free security data attached to cred->security.
(*) security_prepare_creds(), ->cred_prepare()
New. Duplicate any security data attached to cred->security.
(*) security_commit_creds(), ->cred_commit()
New. Apply any security effects for the upcoming installation of new
security by commit_creds().
(*) security_task_post_setuid(), ->task_post_setuid()
Removed in favour of security_task_fix_setuid().
(*) security_task_fix_setuid(), ->task_fix_setuid()
Fix up the proposed new credentials for setuid(). This is used by
cap_set_fix_setuid() to implicitly adjust capabilities in line with
setuid() changes. Changes are made to the new credentials, rather
than the task itself as in security_task_post_setuid().
(*) security_task_reparent_to_init(), ->task_reparent_to_init()
Removed. Instead the task being reparented to init is referred
directly to init's credentials.
NOTE! This results in the loss of some state: SELinux's osid no
longer records the sid of the thread that forked it.
(*) security_key_alloc(), ->key_alloc()
(*) security_key_permission(), ->key_permission()
Changed. These now take cred pointers rather than task pointers to
refer to the security context.
(4) sys_capset().
This has been simplified and uses less locking. The LSM functions it
calls have been merged.
(5) reparent_to_kthreadd().
This gives the current thread the same credentials as init by simply using
commit_thread() to point that way.
(6) __sigqueue_alloc() and switch_uid()
__sigqueue_alloc() can't stop the target task from changing its creds
beneath it, so this function gets a reference to the currently applicable
user_struct which it then passes into the sigqueue struct it returns if
successful.
switch_uid() is now called from commit_creds(), and possibly should be
folded into that. commit_creds() should take care of protecting
__sigqueue_alloc().
(7) [sg]et[ug]id() and co and [sg]et_current_groups.
The set functions now all use prepare_creds(), commit_creds() and
abort_creds() to build and check a new set of credentials before applying
it.
security_task_set[ug]id() is called inside the prepared section. This
guarantees that nothing else will affect the creds until we've finished.
The calling of set_dumpable() has been moved into commit_creds().
Much of the functionality of set_user() has been moved into
commit_creds().
The get functions all simply access the data directly.
(8) security_task_prctl() and cap_task_prctl().
security_task_prctl() has been modified to return -ENOSYS if it doesn't
want to handle a function, or otherwise return the return value directly
rather than through an argument.
Additionally, cap_task_prctl() now prepares a new set of credentials, even
if it doesn't end up using it.
(9) Keyrings.
A number of changes have been made to the keyrings code:
(a) switch_uid_keyring(), copy_keys(), exit_keys() and suid_keys() have
all been dropped and built in to the credentials functions directly.
They may want separating out again later.
(b) key_alloc() and search_process_keyrings() now take a cred pointer
rather than a task pointer to specify the security context.
(c) copy_creds() gives a new thread within the same thread group a new
thread keyring if its parent had one, otherwise it discards the thread
keyring.
(d) The authorisation key now points directly to the credentials to extend
the search into rather pointing to the task that carries them.
(e) Installing thread, process or session keyrings causes a new set of
credentials to be created, even though it's not strictly necessary for
process or session keyrings (they're shared).
(10) Usermode helper.
The usermode helper code now carries a cred struct pointer in its
subprocess_info struct instead of a new session keyring pointer. This set
of credentials is derived from init_cred and installed on the new process
after it has been cloned.
call_usermodehelper_setup() allocates the new credentials and
call_usermodehelper_freeinfo() discards them if they haven't been used. A
special cred function (prepare_usermodeinfo_creds()) is provided
specifically for call_usermodehelper_setup() to call.
call_usermodehelper_setkeys() adjusts the credentials to sport the
supplied keyring as the new session keyring.
(11) SELinux.
SELinux has a number of changes, in addition to those to support the LSM
interface changes mentioned above:
(a) selinux_setprocattr() no longer does its check for whether the
current ptracer can access processes with the new SID inside the lock
that covers getting the ptracer's SID. Whilst this lock ensures that
the check is done with the ptracer pinned, the result is only valid
until the lock is released, so there's no point doing it inside the
lock.
(12) is_single_threaded().
This function has been extracted from selinux_setprocattr() and put into
a file of its own in the lib/ directory as join_session_keyring() now
wants to use it too.
The code in SELinux just checked to see whether a task shared mm_structs
with other tasks (CLONE_VM), but that isn't good enough. We really want
to know if they're part of the same thread group (CLONE_THREAD).
(13) nfsd.
The NFS server daemon now has to use the COW credentials to set the
credentials it is going to use. It really needs to pass the credentials
down to the functions it calls, but it can't do that until other patches
in this series have been applied.
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: James Morris <jmorris@namei.org>
Signed-off-by: James Morris <jmorris@namei.org>
2008-11-13 23:39:23 +00:00
|
|
|
error = security_bounded_transition(tsec->sid, sid);
|
|
|
|
if (error)
|
|
|
|
goto abort_change;
|
2008-04-17 17:17:49 +00:00
|
|
|
}
|
2005-04-16 22:20:36 +00:00
|
|
|
|
|
|
|
/* Check permissions for the transition. */
|
|
|
|
error = avc_has_perm(tsec->sid, sid, SECCLASS_PROCESS,
|
2008-04-17 17:17:49 +00:00
|
|
|
PROCESS__DYNTRANSITION, NULL);
|
2005-04-16 22:20:36 +00:00
|
|
|
if (error)
|
CRED: Inaugurate COW credentials
Inaugurate copy-on-write credentials management. This uses RCU to manage the
credentials pointer in the task_struct with respect to accesses by other tasks.
A process may only modify its own credentials, and so does not need locking to
access or modify its own credentials.
A mutex (cred_replace_mutex) is added to the task_struct to control the effect
of PTRACE_ATTACHED on credential calculations, particularly with respect to
execve().
With this patch, the contents of an active credentials struct may not be
changed directly; rather a new set of credentials must be prepared, modified
and committed using something like the following sequence of events:
struct cred *new = prepare_creds();
int ret = blah(new);
if (ret < 0) {
abort_creds(new);
return ret;
}
return commit_creds(new);
There are some exceptions to this rule: the keyrings pointed to by the active
credentials may be instantiated - keyrings violate the COW rule as managing
COW keyrings is tricky, given that it is possible for a task to directly alter
the keys in a keyring in use by another task.
To help enforce this, various pointers to sets of credentials, such as those in
the task_struct, are declared const. The purpose of this is compile-time
discouragement of altering credentials through those pointers. Once a set of
credentials has been made public through one of these pointers, it may not be
modified, except under special circumstances:
(1) Its reference count may incremented and decremented.
(2) The keyrings to which it points may be modified, but not replaced.
The only safe way to modify anything else is to create a replacement and commit
using the functions described in Documentation/credentials.txt (which will be
added by a later patch).
This patch and the preceding patches have been tested with the LTP SELinux
testsuite.
This patch makes several logical sets of alteration:
(1) execve().
This now prepares and commits credentials in various places in the
security code rather than altering the current creds directly.
(2) Temporary credential overrides.
do_coredump() and sys_faccessat() now prepare their own credentials and
temporarily override the ones currently on the acting thread, whilst
preventing interference from other threads by holding cred_replace_mutex
on the thread being dumped.
This will be replaced in a future patch by something that hands down the
credentials directly to the functions being called, rather than altering
the task's objective credentials.
(3) LSM interface.
A number of functions have been changed, added or removed:
(*) security_capset_check(), ->capset_check()
(*) security_capset_set(), ->capset_set()
Removed in favour of security_capset().
(*) security_capset(), ->capset()
New. This is passed a pointer to the new creds, a pointer to the old
creds and the proposed capability sets. It should fill in the new
creds or return an error. All pointers, barring the pointer to the
new creds, are now const.
(*) security_bprm_apply_creds(), ->bprm_apply_creds()
Changed; now returns a value, which will cause the process to be
killed if it's an error.
(*) security_task_alloc(), ->task_alloc_security()
Removed in favour of security_prepare_creds().
(*) security_cred_free(), ->cred_free()
New. Free security data attached to cred->security.
(*) security_prepare_creds(), ->cred_prepare()
New. Duplicate any security data attached to cred->security.
(*) security_commit_creds(), ->cred_commit()
New. Apply any security effects for the upcoming installation of new
security by commit_creds().
(*) security_task_post_setuid(), ->task_post_setuid()
Removed in favour of security_task_fix_setuid().
(*) security_task_fix_setuid(), ->task_fix_setuid()
Fix up the proposed new credentials for setuid(). This is used by
cap_set_fix_setuid() to implicitly adjust capabilities in line with
setuid() changes. Changes are made to the new credentials, rather
than the task itself as in security_task_post_setuid().
(*) security_task_reparent_to_init(), ->task_reparent_to_init()
Removed. Instead the task being reparented to init is referred
directly to init's credentials.
NOTE! This results in the loss of some state: SELinux's osid no
longer records the sid of the thread that forked it.
(*) security_key_alloc(), ->key_alloc()
(*) security_key_permission(), ->key_permission()
Changed. These now take cred pointers rather than task pointers to
refer to the security context.
(4) sys_capset().
This has been simplified and uses less locking. The LSM functions it
calls have been merged.
(5) reparent_to_kthreadd().
This gives the current thread the same credentials as init by simply using
commit_thread() to point that way.
(6) __sigqueue_alloc() and switch_uid()
__sigqueue_alloc() can't stop the target task from changing its creds
beneath it, so this function gets a reference to the currently applicable
user_struct which it then passes into the sigqueue struct it returns if
successful.
switch_uid() is now called from commit_creds(), and possibly should be
folded into that. commit_creds() should take care of protecting
__sigqueue_alloc().
(7) [sg]et[ug]id() and co and [sg]et_current_groups.
The set functions now all use prepare_creds(), commit_creds() and
abort_creds() to build and check a new set of credentials before applying
it.
security_task_set[ug]id() is called inside the prepared section. This
guarantees that nothing else will affect the creds until we've finished.
The calling of set_dumpable() has been moved into commit_creds().
Much of the functionality of set_user() has been moved into
commit_creds().
The get functions all simply access the data directly.
(8) security_task_prctl() and cap_task_prctl().
security_task_prctl() has been modified to return -ENOSYS if it doesn't
want to handle a function, or otherwise return the return value directly
rather than through an argument.
Additionally, cap_task_prctl() now prepares a new set of credentials, even
if it doesn't end up using it.
(9) Keyrings.
A number of changes have been made to the keyrings code:
(a) switch_uid_keyring(), copy_keys(), exit_keys() and suid_keys() have
all been dropped and built in to the credentials functions directly.
They may want separating out again later.
(b) key_alloc() and search_process_keyrings() now take a cred pointer
rather than a task pointer to specify the security context.
(c) copy_creds() gives a new thread within the same thread group a new
thread keyring if its parent had one, otherwise it discards the thread
keyring.
(d) The authorisation key now points directly to the credentials to extend
the search into rather pointing to the task that carries them.
(e) Installing thread, process or session keyrings causes a new set of
credentials to be created, even though it's not strictly necessary for
process or session keyrings (they're shared).
(10) Usermode helper.
The usermode helper code now carries a cred struct pointer in its
subprocess_info struct instead of a new session keyring pointer. This set
of credentials is derived from init_cred and installed on the new process
after it has been cloned.
call_usermodehelper_setup() allocates the new credentials and
call_usermodehelper_freeinfo() discards them if they haven't been used. A
special cred function (prepare_usermodeinfo_creds()) is provided
specifically for call_usermodehelper_setup() to call.
call_usermodehelper_setkeys() adjusts the credentials to sport the
supplied keyring as the new session keyring.
(11) SELinux.
SELinux has a number of changes, in addition to those to support the LSM
interface changes mentioned above:
(a) selinux_setprocattr() no longer does its check for whether the
current ptracer can access processes with the new SID inside the lock
that covers getting the ptracer's SID. Whilst this lock ensures that
the check is done with the ptracer pinned, the result is only valid
until the lock is released, so there's no point doing it inside the
lock.
(12) is_single_threaded().
This function has been extracted from selinux_setprocattr() and put into
a file of its own in the lib/ directory as join_session_keyring() now
wants to use it too.
The code in SELinux just checked to see whether a task shared mm_structs
with other tasks (CLONE_VM), but that isn't good enough. We really want
to know if they're part of the same thread group (CLONE_THREAD).
(13) nfsd.
The NFS server daemon now has to use the COW credentials to set the
credentials it is going to use. It really needs to pass the credentials
down to the functions it calls, but it can't do that until other patches
in this series have been applied.
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: James Morris <jmorris@namei.org>
Signed-off-by: James Morris <jmorris@namei.org>
2008-11-13 23:39:23 +00:00
|
|
|
goto abort_change;
|
2005-04-16 22:20:36 +00:00
|
|
|
|
|
|
|
/* Check for ptracing, and update the task SID if ok.
|
|
|
|
Otherwise, leave SID unchanged and fail. */
|
CRED: Inaugurate COW credentials
Inaugurate copy-on-write credentials management. This uses RCU to manage the
credentials pointer in the task_struct with respect to accesses by other tasks.
A process may only modify its own credentials, and so does not need locking to
access or modify its own credentials.
A mutex (cred_replace_mutex) is added to the task_struct to control the effect
of PTRACE_ATTACHED on credential calculations, particularly with respect to
execve().
With this patch, the contents of an active credentials struct may not be
changed directly; rather a new set of credentials must be prepared, modified
and committed using something like the following sequence of events:
struct cred *new = prepare_creds();
int ret = blah(new);
if (ret < 0) {
abort_creds(new);
return ret;
}
return commit_creds(new);
There are some exceptions to this rule: the keyrings pointed to by the active
credentials may be instantiated - keyrings violate the COW rule as managing
COW keyrings is tricky, given that it is possible for a task to directly alter
the keys in a keyring in use by another task.
To help enforce this, various pointers to sets of credentials, such as those in
the task_struct, are declared const. The purpose of this is compile-time
discouragement of altering credentials through those pointers. Once a set of
credentials has been made public through one of these pointers, it may not be
modified, except under special circumstances:
(1) Its reference count may incremented and decremented.
(2) The keyrings to which it points may be modified, but not replaced.
The only safe way to modify anything else is to create a replacement and commit
using the functions described in Documentation/credentials.txt (which will be
added by a later patch).
This patch and the preceding patches have been tested with the LTP SELinux
testsuite.
This patch makes several logical sets of alteration:
(1) execve().
This now prepares and commits credentials in various places in the
security code rather than altering the current creds directly.
(2) Temporary credential overrides.
do_coredump() and sys_faccessat() now prepare their own credentials and
temporarily override the ones currently on the acting thread, whilst
preventing interference from other threads by holding cred_replace_mutex
on the thread being dumped.
This will be replaced in a future patch by something that hands down the
credentials directly to the functions being called, rather than altering
the task's objective credentials.
(3) LSM interface.
A number of functions have been changed, added or removed:
(*) security_capset_check(), ->capset_check()
(*) security_capset_set(), ->capset_set()
Removed in favour of security_capset().
(*) security_capset(), ->capset()
New. This is passed a pointer to the new creds, a pointer to the old
creds and the proposed capability sets. It should fill in the new
creds or return an error. All pointers, barring the pointer to the
new creds, are now const.
(*) security_bprm_apply_creds(), ->bprm_apply_creds()
Changed; now returns a value, which will cause the process to be
killed if it's an error.
(*) security_task_alloc(), ->task_alloc_security()
Removed in favour of security_prepare_creds().
(*) security_cred_free(), ->cred_free()
New. Free security data attached to cred->security.
(*) security_prepare_creds(), ->cred_prepare()
New. Duplicate any security data attached to cred->security.
(*) security_commit_creds(), ->cred_commit()
New. Apply any security effects for the upcoming installation of new
security by commit_creds().
(*) security_task_post_setuid(), ->task_post_setuid()
Removed in favour of security_task_fix_setuid().
(*) security_task_fix_setuid(), ->task_fix_setuid()
Fix up the proposed new credentials for setuid(). This is used by
cap_set_fix_setuid() to implicitly adjust capabilities in line with
setuid() changes. Changes are made to the new credentials, rather
than the task itself as in security_task_post_setuid().
(*) security_task_reparent_to_init(), ->task_reparent_to_init()
Removed. Instead the task being reparented to init is referred
directly to init's credentials.
NOTE! This results in the loss of some state: SELinux's osid no
longer records the sid of the thread that forked it.
(*) security_key_alloc(), ->key_alloc()
(*) security_key_permission(), ->key_permission()
Changed. These now take cred pointers rather than task pointers to
refer to the security context.
(4) sys_capset().
This has been simplified and uses less locking. The LSM functions it
calls have been merged.
(5) reparent_to_kthreadd().
This gives the current thread the same credentials as init by simply using
commit_thread() to point that way.
(6) __sigqueue_alloc() and switch_uid()
__sigqueue_alloc() can't stop the target task from changing its creds
beneath it, so this function gets a reference to the currently applicable
user_struct which it then passes into the sigqueue struct it returns if
successful.
switch_uid() is now called from commit_creds(), and possibly should be
folded into that. commit_creds() should take care of protecting
__sigqueue_alloc().
(7) [sg]et[ug]id() and co and [sg]et_current_groups.
The set functions now all use prepare_creds(), commit_creds() and
abort_creds() to build and check a new set of credentials before applying
it.
security_task_set[ug]id() is called inside the prepared section. This
guarantees that nothing else will affect the creds until we've finished.
The calling of set_dumpable() has been moved into commit_creds().
Much of the functionality of set_user() has been moved into
commit_creds().
The get functions all simply access the data directly.
(8) security_task_prctl() and cap_task_prctl().
security_task_prctl() has been modified to return -ENOSYS if it doesn't
want to handle a function, or otherwise return the return value directly
rather than through an argument.
Additionally, cap_task_prctl() now prepares a new set of credentials, even
if it doesn't end up using it.
(9) Keyrings.
A number of changes have been made to the keyrings code:
(a) switch_uid_keyring(), copy_keys(), exit_keys() and suid_keys() have
all been dropped and built in to the credentials functions directly.
They may want separating out again later.
(b) key_alloc() and search_process_keyrings() now take a cred pointer
rather than a task pointer to specify the security context.
(c) copy_creds() gives a new thread within the same thread group a new
thread keyring if its parent had one, otherwise it discards the thread
keyring.
(d) The authorisation key now points directly to the credentials to extend
the search into rather pointing to the task that carries them.
(e) Installing thread, process or session keyrings causes a new set of
credentials to be created, even though it's not strictly necessary for
process or session keyrings (they're shared).
(10) Usermode helper.
The usermode helper code now carries a cred struct pointer in its
subprocess_info struct instead of a new session keyring pointer. This set
of credentials is derived from init_cred and installed on the new process
after it has been cloned.
call_usermodehelper_setup() allocates the new credentials and
call_usermodehelper_freeinfo() discards them if they haven't been used. A
special cred function (prepare_usermodeinfo_creds()) is provided
specifically for call_usermodehelper_setup() to call.
call_usermodehelper_setkeys() adjusts the credentials to sport the
supplied keyring as the new session keyring.
(11) SELinux.
SELinux has a number of changes, in addition to those to support the LSM
interface changes mentioned above:
(a) selinux_setprocattr() no longer does its check for whether the
current ptracer can access processes with the new SID inside the lock
that covers getting the ptracer's SID. Whilst this lock ensures that
the check is done with the ptracer pinned, the result is only valid
until the lock is released, so there's no point doing it inside the
lock.
(12) is_single_threaded().
This function has been extracted from selinux_setprocattr() and put into
a file of its own in the lib/ directory as join_session_keyring() now
wants to use it too.
The code in SELinux just checked to see whether a task shared mm_structs
with other tasks (CLONE_VM), but that isn't good enough. We really want
to know if they're part of the same thread group (CLONE_THREAD).
(13) nfsd.
The NFS server daemon now has to use the COW credentials to set the
credentials it is going to use. It really needs to pass the credentials
down to the functions it calls, but it can't do that until other patches
in this series have been applied.
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: James Morris <jmorris@namei.org>
Signed-off-by: James Morris <jmorris@namei.org>
2008-11-13 23:39:23 +00:00
|
|
|
ptsid = 0;
|
2013-12-23 22:45:01 +00:00
|
|
|
rcu_read_lock();
|
2011-06-17 14:50:40 +00:00
|
|
|
tracer = ptrace_parent(p);
|
CRED: Inaugurate COW credentials
Inaugurate copy-on-write credentials management. This uses RCU to manage the
credentials pointer in the task_struct with respect to accesses by other tasks.
A process may only modify its own credentials, and so does not need locking to
access or modify its own credentials.
A mutex (cred_replace_mutex) is added to the task_struct to control the effect
of PTRACE_ATTACHED on credential calculations, particularly with respect to
execve().
With this patch, the contents of an active credentials struct may not be
changed directly; rather a new set of credentials must be prepared, modified
and committed using something like the following sequence of events:
struct cred *new = prepare_creds();
int ret = blah(new);
if (ret < 0) {
abort_creds(new);
return ret;
}
return commit_creds(new);
There are some exceptions to this rule: the keyrings pointed to by the active
credentials may be instantiated - keyrings violate the COW rule as managing
COW keyrings is tricky, given that it is possible for a task to directly alter
the keys in a keyring in use by another task.
To help enforce this, various pointers to sets of credentials, such as those in
the task_struct, are declared const. The purpose of this is compile-time
discouragement of altering credentials through those pointers. Once a set of
credentials has been made public through one of these pointers, it may not be
modified, except under special circumstances:
(1) Its reference count may incremented and decremented.
(2) The keyrings to which it points may be modified, but not replaced.
The only safe way to modify anything else is to create a replacement and commit
using the functions described in Documentation/credentials.txt (which will be
added by a later patch).
This patch and the preceding patches have been tested with the LTP SELinux
testsuite.
This patch makes several logical sets of alteration:
(1) execve().
This now prepares and commits credentials in various places in the
security code rather than altering the current creds directly.
(2) Temporary credential overrides.
do_coredump() and sys_faccessat() now prepare their own credentials and
temporarily override the ones currently on the acting thread, whilst
preventing interference from other threads by holding cred_replace_mutex
on the thread being dumped.
This will be replaced in a future patch by something that hands down the
credentials directly to the functions being called, rather than altering
the task's objective credentials.
(3) LSM interface.
A number of functions have been changed, added or removed:
(*) security_capset_check(), ->capset_check()
(*) security_capset_set(), ->capset_set()
Removed in favour of security_capset().
(*) security_capset(), ->capset()
New. This is passed a pointer to the new creds, a pointer to the old
creds and the proposed capability sets. It should fill in the new
creds or return an error. All pointers, barring the pointer to the
new creds, are now const.
(*) security_bprm_apply_creds(), ->bprm_apply_creds()
Changed; now returns a value, which will cause the process to be
killed if it's an error.
(*) security_task_alloc(), ->task_alloc_security()
Removed in favour of security_prepare_creds().
(*) security_cred_free(), ->cred_free()
New. Free security data attached to cred->security.
(*) security_prepare_creds(), ->cred_prepare()
New. Duplicate any security data attached to cred->security.
(*) security_commit_creds(), ->cred_commit()
New. Apply any security effects for the upcoming installation of new
security by commit_creds().
(*) security_task_post_setuid(), ->task_post_setuid()
Removed in favour of security_task_fix_setuid().
(*) security_task_fix_setuid(), ->task_fix_setuid()
Fix up the proposed new credentials for setuid(). This is used by
cap_set_fix_setuid() to implicitly adjust capabilities in line with
setuid() changes. Changes are made to the new credentials, rather
than the task itself as in security_task_post_setuid().
(*) security_task_reparent_to_init(), ->task_reparent_to_init()
Removed. Instead the task being reparented to init is referred
directly to init's credentials.
NOTE! This results in the loss of some state: SELinux's osid no
longer records the sid of the thread that forked it.
(*) security_key_alloc(), ->key_alloc()
(*) security_key_permission(), ->key_permission()
Changed. These now take cred pointers rather than task pointers to
refer to the security context.
(4) sys_capset().
This has been simplified and uses less locking. The LSM functions it
calls have been merged.
(5) reparent_to_kthreadd().
This gives the current thread the same credentials as init by simply using
commit_thread() to point that way.
(6) __sigqueue_alloc() and switch_uid()
__sigqueue_alloc() can't stop the target task from changing its creds
beneath it, so this function gets a reference to the currently applicable
user_struct which it then passes into the sigqueue struct it returns if
successful.
switch_uid() is now called from commit_creds(), and possibly should be
folded into that. commit_creds() should take care of protecting
__sigqueue_alloc().
(7) [sg]et[ug]id() and co and [sg]et_current_groups.
The set functions now all use prepare_creds(), commit_creds() and
abort_creds() to build and check a new set of credentials before applying
it.
security_task_set[ug]id() is called inside the prepared section. This
guarantees that nothing else will affect the creds until we've finished.
The calling of set_dumpable() has been moved into commit_creds().
Much of the functionality of set_user() has been moved into
commit_creds().
The get functions all simply access the data directly.
(8) security_task_prctl() and cap_task_prctl().
security_task_prctl() has been modified to return -ENOSYS if it doesn't
want to handle a function, or otherwise return the return value directly
rather than through an argument.
Additionally, cap_task_prctl() now prepares a new set of credentials, even
if it doesn't end up using it.
(9) Keyrings.
A number of changes have been made to the keyrings code:
(a) switch_uid_keyring(), copy_keys(), exit_keys() and suid_keys() have
all been dropped and built in to the credentials functions directly.
They may want separating out again later.
(b) key_alloc() and search_process_keyrings() now take a cred pointer
rather than a task pointer to specify the security context.
(c) copy_creds() gives a new thread within the same thread group a new
thread keyring if its parent had one, otherwise it discards the thread
keyring.
(d) The authorisation key now points directly to the credentials to extend
the search into rather pointing to the task that carries them.
(e) Installing thread, process or session keyrings causes a new set of
credentials to be created, even though it's not strictly necessary for
process or session keyrings (they're shared).
(10) Usermode helper.
The usermode helper code now carries a cred struct pointer in its
subprocess_info struct instead of a new session keyring pointer. This set
of credentials is derived from init_cred and installed on the new process
after it has been cloned.
call_usermodehelper_setup() allocates the new credentials and
call_usermodehelper_freeinfo() discards them if they haven't been used. A
special cred function (prepare_usermodeinfo_creds()) is provided
specifically for call_usermodehelper_setup() to call.
call_usermodehelper_setkeys() adjusts the credentials to sport the
supplied keyring as the new session keyring.
(11) SELinux.
SELinux has a number of changes, in addition to those to support the LSM
interface changes mentioned above:
(a) selinux_setprocattr() no longer does its check for whether the
current ptracer can access processes with the new SID inside the lock
that covers getting the ptracer's SID. Whilst this lock ensures that
the check is done with the ptracer pinned, the result is only valid
until the lock is released, so there's no point doing it inside the
lock.
(12) is_single_threaded().
This function has been extracted from selinux_setprocattr() and put into
a file of its own in the lib/ directory as join_session_keyring() now
wants to use it too.
The code in SELinux just checked to see whether a task shared mm_structs
with other tasks (CLONE_VM), but that isn't good enough. We really want
to know if they're part of the same thread group (CLONE_THREAD).
(13) nfsd.
The NFS server daemon now has to use the COW credentials to set the
credentials it is going to use. It really needs to pass the credentials
down to the functions it calls, but it can't do that until other patches
in this series have been applied.
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: James Morris <jmorris@namei.org>
Signed-off-by: James Morris <jmorris@namei.org>
2008-11-13 23:39:23 +00:00
|
|
|
if (tracer)
|
|
|
|
ptsid = task_sid(tracer);
|
2013-12-23 22:45:01 +00:00
|
|
|
rcu_read_unlock();
|
CRED: Inaugurate COW credentials
Inaugurate copy-on-write credentials management. This uses RCU to manage the
credentials pointer in the task_struct with respect to accesses by other tasks.
A process may only modify its own credentials, and so does not need locking to
access or modify its own credentials.
A mutex (cred_replace_mutex) is added to the task_struct to control the effect
of PTRACE_ATTACHED on credential calculations, particularly with respect to
execve().
With this patch, the contents of an active credentials struct may not be
changed directly; rather a new set of credentials must be prepared, modified
and committed using something like the following sequence of events:
struct cred *new = prepare_creds();
int ret = blah(new);
if (ret < 0) {
abort_creds(new);
return ret;
}
return commit_creds(new);
There are some exceptions to this rule: the keyrings pointed to by the active
credentials may be instantiated - keyrings violate the COW rule as managing
COW keyrings is tricky, given that it is possible for a task to directly alter
the keys in a keyring in use by another task.
To help enforce this, various pointers to sets of credentials, such as those in
the task_struct, are declared const. The purpose of this is compile-time
discouragement of altering credentials through those pointers. Once a set of
credentials has been made public through one of these pointers, it may not be
modified, except under special circumstances:
(1) Its reference count may incremented and decremented.
(2) The keyrings to which it points may be modified, but not replaced.
The only safe way to modify anything else is to create a replacement and commit
using the functions described in Documentation/credentials.txt (which will be
added by a later patch).
This patch and the preceding patches have been tested with the LTP SELinux
testsuite.
This patch makes several logical sets of alteration:
(1) execve().
This now prepares and commits credentials in various places in the
security code rather than altering the current creds directly.
(2) Temporary credential overrides.
do_coredump() and sys_faccessat() now prepare their own credentials and
temporarily override the ones currently on the acting thread, whilst
preventing interference from other threads by holding cred_replace_mutex
on the thread being dumped.
This will be replaced in a future patch by something that hands down the
credentials directly to the functions being called, rather than altering
the task's objective credentials.
(3) LSM interface.
A number of functions have been changed, added or removed:
(*) security_capset_check(), ->capset_check()
(*) security_capset_set(), ->capset_set()
Removed in favour of security_capset().
(*) security_capset(), ->capset()
New. This is passed a pointer to the new creds, a pointer to the old
creds and the proposed capability sets. It should fill in the new
creds or return an error. All pointers, barring the pointer to the
new creds, are now const.
(*) security_bprm_apply_creds(), ->bprm_apply_creds()
Changed; now returns a value, which will cause the process to be
killed if it's an error.
(*) security_task_alloc(), ->task_alloc_security()
Removed in favour of security_prepare_creds().
(*) security_cred_free(), ->cred_free()
New. Free security data attached to cred->security.
(*) security_prepare_creds(), ->cred_prepare()
New. Duplicate any security data attached to cred->security.
(*) security_commit_creds(), ->cred_commit()
New. Apply any security effects for the upcoming installation of new
security by commit_creds().
(*) security_task_post_setuid(), ->task_post_setuid()
Removed in favour of security_task_fix_setuid().
(*) security_task_fix_setuid(), ->task_fix_setuid()
Fix up the proposed new credentials for setuid(). This is used by
cap_set_fix_setuid() to implicitly adjust capabilities in line with
setuid() changes. Changes are made to the new credentials, rather
than the task itself as in security_task_post_setuid().
(*) security_task_reparent_to_init(), ->task_reparent_to_init()
Removed. Instead the task being reparented to init is referred
directly to init's credentials.
NOTE! This results in the loss of some state: SELinux's osid no
longer records the sid of the thread that forked it.
(*) security_key_alloc(), ->key_alloc()
(*) security_key_permission(), ->key_permission()
Changed. These now take cred pointers rather than task pointers to
refer to the security context.
(4) sys_capset().
This has been simplified and uses less locking. The LSM functions it
calls have been merged.
(5) reparent_to_kthreadd().
This gives the current thread the same credentials as init by simply using
commit_thread() to point that way.
(6) __sigqueue_alloc() and switch_uid()
__sigqueue_alloc() can't stop the target task from changing its creds
beneath it, so this function gets a reference to the currently applicable
user_struct which it then passes into the sigqueue struct it returns if
successful.
switch_uid() is now called from commit_creds(), and possibly should be
folded into that. commit_creds() should take care of protecting
__sigqueue_alloc().
(7) [sg]et[ug]id() and co and [sg]et_current_groups.
The set functions now all use prepare_creds(), commit_creds() and
abort_creds() to build and check a new set of credentials before applying
it.
security_task_set[ug]id() is called inside the prepared section. This
guarantees that nothing else will affect the creds until we've finished.
The calling of set_dumpable() has been moved into commit_creds().
Much of the functionality of set_user() has been moved into
commit_creds().
The get functions all simply access the data directly.
(8) security_task_prctl() and cap_task_prctl().
security_task_prctl() has been modified to return -ENOSYS if it doesn't
want to handle a function, or otherwise return the return value directly
rather than through an argument.
Additionally, cap_task_prctl() now prepares a new set of credentials, even
if it doesn't end up using it.
(9) Keyrings.
A number of changes have been made to the keyrings code:
(a) switch_uid_keyring(), copy_keys(), exit_keys() and suid_keys() have
all been dropped and built in to the credentials functions directly.
They may want separating out again later.
(b) key_alloc() and search_process_keyrings() now take a cred pointer
rather than a task pointer to specify the security context.
(c) copy_creds() gives a new thread within the same thread group a new
thread keyring if its parent had one, otherwise it discards the thread
keyring.
(d) The authorisation key now points directly to the credentials to extend
the search into rather pointing to the task that carries them.
(e) Installing thread, process or session keyrings causes a new set of
credentials to be created, even though it's not strictly necessary for
process or session keyrings (they're shared).
(10) Usermode helper.
The usermode helper code now carries a cred struct pointer in its
subprocess_info struct instead of a new session keyring pointer. This set
of credentials is derived from init_cred and installed on the new process
after it has been cloned.
call_usermodehelper_setup() allocates the new credentials and
call_usermodehelper_freeinfo() discards them if they haven't been used. A
special cred function (prepare_usermodeinfo_creds()) is provided
specifically for call_usermodehelper_setup() to call.
call_usermodehelper_setkeys() adjusts the credentials to sport the
supplied keyring as the new session keyring.
(11) SELinux.
SELinux has a number of changes, in addition to those to support the LSM
interface changes mentioned above:
(a) selinux_setprocattr() no longer does its check for whether the
current ptracer can access processes with the new SID inside the lock
that covers getting the ptracer's SID. Whilst this lock ensures that
the check is done with the ptracer pinned, the result is only valid
until the lock is released, so there's no point doing it inside the
lock.
(12) is_single_threaded().
This function has been extracted from selinux_setprocattr() and put into
a file of its own in the lib/ directory as join_session_keyring() now
wants to use it too.
The code in SELinux just checked to see whether a task shared mm_structs
with other tasks (CLONE_VM), but that isn't good enough. We really want
to know if they're part of the same thread group (CLONE_THREAD).
(13) nfsd.
The NFS server daemon now has to use the COW credentials to set the
credentials it is going to use. It really needs to pass the credentials
down to the functions it calls, but it can't do that until other patches
in this series have been applied.
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: James Morris <jmorris@namei.org>
Signed-off-by: James Morris <jmorris@namei.org>
2008-11-13 23:39:23 +00:00
|
|
|
|
|
|
|
if (tracer) {
|
|
|
|
error = avc_has_perm(ptsid, sid, SECCLASS_PROCESS,
|
|
|
|
PROCESS__PTRACE, NULL);
|
2005-04-16 22:20:36 +00:00
|
|
|
if (error)
|
CRED: Inaugurate COW credentials
Inaugurate copy-on-write credentials management. This uses RCU to manage the
credentials pointer in the task_struct with respect to accesses by other tasks.
A process may only modify its own credentials, and so does not need locking to
access or modify its own credentials.
A mutex (cred_replace_mutex) is added to the task_struct to control the effect
of PTRACE_ATTACHED on credential calculations, particularly with respect to
execve().
With this patch, the contents of an active credentials struct may not be
changed directly; rather a new set of credentials must be prepared, modified
and committed using something like the following sequence of events:
struct cred *new = prepare_creds();
int ret = blah(new);
if (ret < 0) {
abort_creds(new);
return ret;
}
return commit_creds(new);
There are some exceptions to this rule: the keyrings pointed to by the active
credentials may be instantiated - keyrings violate the COW rule as managing
COW keyrings is tricky, given that it is possible for a task to directly alter
the keys in a keyring in use by another task.
To help enforce this, various pointers to sets of credentials, such as those in
the task_struct, are declared const. The purpose of this is compile-time
discouragement of altering credentials through those pointers. Once a set of
credentials has been made public through one of these pointers, it may not be
modified, except under special circumstances:
(1) Its reference count may incremented and decremented.
(2) The keyrings to which it points may be modified, but not replaced.
The only safe way to modify anything else is to create a replacement and commit
using the functions described in Documentation/credentials.txt (which will be
added by a later patch).
This patch and the preceding patches have been tested with the LTP SELinux
testsuite.
This patch makes several logical sets of alteration:
(1) execve().
This now prepares and commits credentials in various places in the
security code rather than altering the current creds directly.
(2) Temporary credential overrides.
do_coredump() and sys_faccessat() now prepare their own credentials and
temporarily override the ones currently on the acting thread, whilst
preventing interference from other threads by holding cred_replace_mutex
on the thread being dumped.
This will be replaced in a future patch by something that hands down the
credentials directly to the functions being called, rather than altering
the task's objective credentials.
(3) LSM interface.
A number of functions have been changed, added or removed:
(*) security_capset_check(), ->capset_check()
(*) security_capset_set(), ->capset_set()
Removed in favour of security_capset().
(*) security_capset(), ->capset()
New. This is passed a pointer to the new creds, a pointer to the old
creds and the proposed capability sets. It should fill in the new
creds or return an error. All pointers, barring the pointer to the
new creds, are now const.
(*) security_bprm_apply_creds(), ->bprm_apply_creds()
Changed; now returns a value, which will cause the process to be
killed if it's an error.
(*) security_task_alloc(), ->task_alloc_security()
Removed in favour of security_prepare_creds().
(*) security_cred_free(), ->cred_free()
New. Free security data attached to cred->security.
(*) security_prepare_creds(), ->cred_prepare()
New. Duplicate any security data attached to cred->security.
(*) security_commit_creds(), ->cred_commit()
New. Apply any security effects for the upcoming installation of new
security by commit_creds().
(*) security_task_post_setuid(), ->task_post_setuid()
Removed in favour of security_task_fix_setuid().
(*) security_task_fix_setuid(), ->task_fix_setuid()
Fix up the proposed new credentials for setuid(). This is used by
cap_set_fix_setuid() to implicitly adjust capabilities in line with
setuid() changes. Changes are made to the new credentials, rather
than the task itself as in security_task_post_setuid().
(*) security_task_reparent_to_init(), ->task_reparent_to_init()
Removed. Instead the task being reparented to init is referred
directly to init's credentials.
NOTE! This results in the loss of some state: SELinux's osid no
longer records the sid of the thread that forked it.
(*) security_key_alloc(), ->key_alloc()
(*) security_key_permission(), ->key_permission()
Changed. These now take cred pointers rather than task pointers to
refer to the security context.
(4) sys_capset().
This has been simplified and uses less locking. The LSM functions it
calls have been merged.
(5) reparent_to_kthreadd().
This gives the current thread the same credentials as init by simply using
commit_thread() to point that way.
(6) __sigqueue_alloc() and switch_uid()
__sigqueue_alloc() can't stop the target task from changing its creds
beneath it, so this function gets a reference to the currently applicable
user_struct which it then passes into the sigqueue struct it returns if
successful.
switch_uid() is now called from commit_creds(), and possibly should be
folded into that. commit_creds() should take care of protecting
__sigqueue_alloc().
(7) [sg]et[ug]id() and co and [sg]et_current_groups.
The set functions now all use prepare_creds(), commit_creds() and
abort_creds() to build and check a new set of credentials before applying
it.
security_task_set[ug]id() is called inside the prepared section. This
guarantees that nothing else will affect the creds until we've finished.
The calling of set_dumpable() has been moved into commit_creds().
Much of the functionality of set_user() has been moved into
commit_creds().
The get functions all simply access the data directly.
(8) security_task_prctl() and cap_task_prctl().
security_task_prctl() has been modified to return -ENOSYS if it doesn't
want to handle a function, or otherwise return the return value directly
rather than through an argument.
Additionally, cap_task_prctl() now prepares a new set of credentials, even
if it doesn't end up using it.
(9) Keyrings.
A number of changes have been made to the keyrings code:
(a) switch_uid_keyring(), copy_keys(), exit_keys() and suid_keys() have
all been dropped and built in to the credentials functions directly.
They may want separating out again later.
(b) key_alloc() and search_process_keyrings() now take a cred pointer
rather than a task pointer to specify the security context.
(c) copy_creds() gives a new thread within the same thread group a new
thread keyring if its parent had one, otherwise it discards the thread
keyring.
(d) The authorisation key now points directly to the credentials to extend
the search into rather pointing to the task that carries them.
(e) Installing thread, process or session keyrings causes a new set of
credentials to be created, even though it's not strictly necessary for
process or session keyrings (they're shared).
(10) Usermode helper.
The usermode helper code now carries a cred struct pointer in its
subprocess_info struct instead of a new session keyring pointer. This set
of credentials is derived from init_cred and installed on the new process
after it has been cloned.
call_usermodehelper_setup() allocates the new credentials and
call_usermodehelper_freeinfo() discards them if they haven't been used. A
special cred function (prepare_usermodeinfo_creds()) is provided
specifically for call_usermodehelper_setup() to call.
call_usermodehelper_setkeys() adjusts the credentials to sport the
supplied keyring as the new session keyring.
(11) SELinux.
SELinux has a number of changes, in addition to those to support the LSM
interface changes mentioned above:
(a) selinux_setprocattr() no longer does its check for whether the
current ptracer can access processes with the new SID inside the lock
that covers getting the ptracer's SID. Whilst this lock ensures that
the check is done with the ptracer pinned, the result is only valid
until the lock is released, so there's no point doing it inside the
lock.
(12) is_single_threaded().
This function has been extracted from selinux_setprocattr() and put into
a file of its own in the lib/ directory as join_session_keyring() now
wants to use it too.
The code in SELinux just checked to see whether a task shared mm_structs
with other tasks (CLONE_VM), but that isn't good enough. We really want
to know if they're part of the same thread group (CLONE_THREAD).
(13) nfsd.
The NFS server daemon now has to use the COW credentials to set the
credentials it is going to use. It really needs to pass the credentials
down to the functions it calls, but it can't do that until other patches
in this series have been applied.
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: James Morris <jmorris@namei.org>
Signed-off-by: James Morris <jmorris@namei.org>
2008-11-13 23:39:23 +00:00
|
|
|
goto abort_change;
|
2005-04-16 22:20:36 +00:00
|
|
|
}
|
|
|
|
|
CRED: Inaugurate COW credentials
Inaugurate copy-on-write credentials management. This uses RCU to manage the
credentials pointer in the task_struct with respect to accesses by other tasks.
A process may only modify its own credentials, and so does not need locking to
access or modify its own credentials.
A mutex (cred_replace_mutex) is added to the task_struct to control the effect
of PTRACE_ATTACHED on credential calculations, particularly with respect to
execve().
With this patch, the contents of an active credentials struct may not be
changed directly; rather a new set of credentials must be prepared, modified
and committed using something like the following sequence of events:
struct cred *new = prepare_creds();
int ret = blah(new);
if (ret < 0) {
abort_creds(new);
return ret;
}
return commit_creds(new);
There are some exceptions to this rule: the keyrings pointed to by the active
credentials may be instantiated - keyrings violate the COW rule as managing
COW keyrings is tricky, given that it is possible for a task to directly alter
the keys in a keyring in use by another task.
To help enforce this, various pointers to sets of credentials, such as those in
the task_struct, are declared const. The purpose of this is compile-time
discouragement of altering credentials through those pointers. Once a set of
credentials has been made public through one of these pointers, it may not be
modified, except under special circumstances:
(1) Its reference count may incremented and decremented.
(2) The keyrings to which it points may be modified, but not replaced.
The only safe way to modify anything else is to create a replacement and commit
using the functions described in Documentation/credentials.txt (which will be
added by a later patch).
This patch and the preceding patches have been tested with the LTP SELinux
testsuite.
This patch makes several logical sets of alteration:
(1) execve().
This now prepares and commits credentials in various places in the
security code rather than altering the current creds directly.
(2) Temporary credential overrides.
do_coredump() and sys_faccessat() now prepare their own credentials and
temporarily override the ones currently on the acting thread, whilst
preventing interference from other threads by holding cred_replace_mutex
on the thread being dumped.
This will be replaced in a future patch by something that hands down the
credentials directly to the functions being called, rather than altering
the task's objective credentials.
(3) LSM interface.
A number of functions have been changed, added or removed:
(*) security_capset_check(), ->capset_check()
(*) security_capset_set(), ->capset_set()
Removed in favour of security_capset().
(*) security_capset(), ->capset()
New. This is passed a pointer to the new creds, a pointer to the old
creds and the proposed capability sets. It should fill in the new
creds or return an error. All pointers, barring the pointer to the
new creds, are now const.
(*) security_bprm_apply_creds(), ->bprm_apply_creds()
Changed; now returns a value, which will cause the process to be
killed if it's an error.
(*) security_task_alloc(), ->task_alloc_security()
Removed in favour of security_prepare_creds().
(*) security_cred_free(), ->cred_free()
New. Free security data attached to cred->security.
(*) security_prepare_creds(), ->cred_prepare()
New. Duplicate any security data attached to cred->security.
(*) security_commit_creds(), ->cred_commit()
New. Apply any security effects for the upcoming installation of new
security by commit_creds().
(*) security_task_post_setuid(), ->task_post_setuid()
Removed in favour of security_task_fix_setuid().
(*) security_task_fix_setuid(), ->task_fix_setuid()
Fix up the proposed new credentials for setuid(). This is used by
cap_set_fix_setuid() to implicitly adjust capabilities in line with
setuid() changes. Changes are made to the new credentials, rather
than the task itself as in security_task_post_setuid().
(*) security_task_reparent_to_init(), ->task_reparent_to_init()
Removed. Instead the task being reparented to init is referred
directly to init's credentials.
NOTE! This results in the loss of some state: SELinux's osid no
longer records the sid of the thread that forked it.
(*) security_key_alloc(), ->key_alloc()
(*) security_key_permission(), ->key_permission()
Changed. These now take cred pointers rather than task pointers to
refer to the security context.
(4) sys_capset().
This has been simplified and uses less locking. The LSM functions it
calls have been merged.
(5) reparent_to_kthreadd().
This gives the current thread the same credentials as init by simply using
commit_thread() to point that way.
(6) __sigqueue_alloc() and switch_uid()
__sigqueue_alloc() can't stop the target task from changing its creds
beneath it, so this function gets a reference to the currently applicable
user_struct which it then passes into the sigqueue struct it returns if
successful.
switch_uid() is now called from commit_creds(), and possibly should be
folded into that. commit_creds() should take care of protecting
__sigqueue_alloc().
(7) [sg]et[ug]id() and co and [sg]et_current_groups.
The set functions now all use prepare_creds(), commit_creds() and
abort_creds() to build and check a new set of credentials before applying
it.
security_task_set[ug]id() is called inside the prepared section. This
guarantees that nothing else will affect the creds until we've finished.
The calling of set_dumpable() has been moved into commit_creds().
Much of the functionality of set_user() has been moved into
commit_creds().
The get functions all simply access the data directly.
(8) security_task_prctl() and cap_task_prctl().
security_task_prctl() has been modified to return -ENOSYS if it doesn't
want to handle a function, or otherwise return the return value directly
rather than through an argument.
Additionally, cap_task_prctl() now prepares a new set of credentials, even
if it doesn't end up using it.
(9) Keyrings.
A number of changes have been made to the keyrings code:
(a) switch_uid_keyring(), copy_keys(), exit_keys() and suid_keys() have
all been dropped and built in to the credentials functions directly.
They may want separating out again later.
(b) key_alloc() and search_process_keyrings() now take a cred pointer
rather than a task pointer to specify the security context.
(c) copy_creds() gives a new thread within the same thread group a new
thread keyring if its parent had one, otherwise it discards the thread
keyring.
(d) The authorisation key now points directly to the credentials to extend
the search into rather pointing to the task that carries them.
(e) Installing thread, process or session keyrings causes a new set of
credentials to be created, even though it's not strictly necessary for
process or session keyrings (they're shared).
(10) Usermode helper.
The usermode helper code now carries a cred struct pointer in its
subprocess_info struct instead of a new session keyring pointer. This set
of credentials is derived from init_cred and installed on the new process
after it has been cloned.
call_usermodehelper_setup() allocates the new credentials and
call_usermodehelper_freeinfo() discards them if they haven't been used. A
special cred function (prepare_usermodeinfo_creds()) is provided
specifically for call_usermodehelper_setup() to call.
call_usermodehelper_setkeys() adjusts the credentials to sport the
supplied keyring as the new session keyring.
(11) SELinux.
SELinux has a number of changes, in addition to those to support the LSM
interface changes mentioned above:
(a) selinux_setprocattr() no longer does its check for whether the
current ptracer can access processes with the new SID inside the lock
that covers getting the ptracer's SID. Whilst this lock ensures that
the check is done with the ptracer pinned, the result is only valid
until the lock is released, so there's no point doing it inside the
lock.
(12) is_single_threaded().
This function has been extracted from selinux_setprocattr() and put into
a file of its own in the lib/ directory as join_session_keyring() now
wants to use it too.
The code in SELinux just checked to see whether a task shared mm_structs
with other tasks (CLONE_VM), but that isn't good enough. We really want
to know if they're part of the same thread group (CLONE_THREAD).
(13) nfsd.
The NFS server daemon now has to use the COW credentials to set the
credentials it is going to use. It really needs to pass the credentials
down to the functions it calls, but it can't do that until other patches
in this series have been applied.
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: James Morris <jmorris@namei.org>
Signed-off-by: James Morris <jmorris@namei.org>
2008-11-13 23:39:23 +00:00
|
|
|
tsec->sid = sid;
|
|
|
|
} else {
|
|
|
|
error = -EINVAL;
|
|
|
|
goto abort_change;
|
|
|
|
}
|
|
|
|
|
|
|
|
commit_creds(new);
|
2005-04-16 22:20:36 +00:00
|
|
|
return size;
|
CRED: Inaugurate COW credentials
Inaugurate copy-on-write credentials management. This uses RCU to manage the
credentials pointer in the task_struct with respect to accesses by other tasks.
A process may only modify its own credentials, and so does not need locking to
access or modify its own credentials.
A mutex (cred_replace_mutex) is added to the task_struct to control the effect
of PTRACE_ATTACHED on credential calculations, particularly with respect to
execve().
With this patch, the contents of an active credentials struct may not be
changed directly; rather a new set of credentials must be prepared, modified
and committed using something like the following sequence of events:
struct cred *new = prepare_creds();
int ret = blah(new);
if (ret < 0) {
abort_creds(new);
return ret;
}
return commit_creds(new);
There are some exceptions to this rule: the keyrings pointed to by the active
credentials may be instantiated - keyrings violate the COW rule as managing
COW keyrings is tricky, given that it is possible for a task to directly alter
the keys in a keyring in use by another task.
To help enforce this, various pointers to sets of credentials, such as those in
the task_struct, are declared const. The purpose of this is compile-time
discouragement of altering credentials through those pointers. Once a set of
credentials has been made public through one of these pointers, it may not be
modified, except under special circumstances:
(1) Its reference count may incremented and decremented.
(2) The keyrings to which it points may be modified, but not replaced.
The only safe way to modify anything else is to create a replacement and commit
using the functions described in Documentation/credentials.txt (which will be
added by a later patch).
This patch and the preceding patches have been tested with the LTP SELinux
testsuite.
This patch makes several logical sets of alteration:
(1) execve().
This now prepares and commits credentials in various places in the
security code rather than altering the current creds directly.
(2) Temporary credential overrides.
do_coredump() and sys_faccessat() now prepare their own credentials and
temporarily override the ones currently on the acting thread, whilst
preventing interference from other threads by holding cred_replace_mutex
on the thread being dumped.
This will be replaced in a future patch by something that hands down the
credentials directly to the functions being called, rather than altering
the task's objective credentials.
(3) LSM interface.
A number of functions have been changed, added or removed:
(*) security_capset_check(), ->capset_check()
(*) security_capset_set(), ->capset_set()
Removed in favour of security_capset().
(*) security_capset(), ->capset()
New. This is passed a pointer to the new creds, a pointer to the old
creds and the proposed capability sets. It should fill in the new
creds or return an error. All pointers, barring the pointer to the
new creds, are now const.
(*) security_bprm_apply_creds(), ->bprm_apply_creds()
Changed; now returns a value, which will cause the process to be
killed if it's an error.
(*) security_task_alloc(), ->task_alloc_security()
Removed in favour of security_prepare_creds().
(*) security_cred_free(), ->cred_free()
New. Free security data attached to cred->security.
(*) security_prepare_creds(), ->cred_prepare()
New. Duplicate any security data attached to cred->security.
(*) security_commit_creds(), ->cred_commit()
New. Apply any security effects for the upcoming installation of new
security by commit_creds().
(*) security_task_post_setuid(), ->task_post_setuid()
Removed in favour of security_task_fix_setuid().
(*) security_task_fix_setuid(), ->task_fix_setuid()
Fix up the proposed new credentials for setuid(). This is used by
cap_set_fix_setuid() to implicitly adjust capabilities in line with
setuid() changes. Changes are made to the new credentials, rather
than the task itself as in security_task_post_setuid().
(*) security_task_reparent_to_init(), ->task_reparent_to_init()
Removed. Instead the task being reparented to init is referred
directly to init's credentials.
NOTE! This results in the loss of some state: SELinux's osid no
longer records the sid of the thread that forked it.
(*) security_key_alloc(), ->key_alloc()
(*) security_key_permission(), ->key_permission()
Changed. These now take cred pointers rather than task pointers to
refer to the security context.
(4) sys_capset().
This has been simplified and uses less locking. The LSM functions it
calls have been merged.
(5) reparent_to_kthreadd().
This gives the current thread the same credentials as init by simply using
commit_thread() to point that way.
(6) __sigqueue_alloc() and switch_uid()
__sigqueue_alloc() can't stop the target task from changing its creds
beneath it, so this function gets a reference to the currently applicable
user_struct which it then passes into the sigqueue struct it returns if
successful.
switch_uid() is now called from commit_creds(), and possibly should be
folded into that. commit_creds() should take care of protecting
__sigqueue_alloc().
(7) [sg]et[ug]id() and co and [sg]et_current_groups.
The set functions now all use prepare_creds(), commit_creds() and
abort_creds() to build and check a new set of credentials before applying
it.
security_task_set[ug]id() is called inside the prepared section. This
guarantees that nothing else will affect the creds until we've finished.
The calling of set_dumpable() has been moved into commit_creds().
Much of the functionality of set_user() has been moved into
commit_creds().
The get functions all simply access the data directly.
(8) security_task_prctl() and cap_task_prctl().
security_task_prctl() has been modified to return -ENOSYS if it doesn't
want to handle a function, or otherwise return the return value directly
rather than through an argument.
Additionally, cap_task_prctl() now prepares a new set of credentials, even
if it doesn't end up using it.
(9) Keyrings.
A number of changes have been made to the keyrings code:
(a) switch_uid_keyring(), copy_keys(), exit_keys() and suid_keys() have
all been dropped and built in to the credentials functions directly.
They may want separating out again later.
(b) key_alloc() and search_process_keyrings() now take a cred pointer
rather than a task pointer to specify the security context.
(c) copy_creds() gives a new thread within the same thread group a new
thread keyring if its parent had one, otherwise it discards the thread
keyring.
(d) The authorisation key now points directly to the credentials to extend
the search into rather pointing to the task that carries them.
(e) Installing thread, process or session keyrings causes a new set of
credentials to be created, even though it's not strictly necessary for
process or session keyrings (they're shared).
(10) Usermode helper.
The usermode helper code now carries a cred struct pointer in its
subprocess_info struct instead of a new session keyring pointer. This set
of credentials is derived from init_cred and installed on the new process
after it has been cloned.
call_usermodehelper_setup() allocates the new credentials and
call_usermodehelper_freeinfo() discards them if they haven't been used. A
special cred function (prepare_usermodeinfo_creds()) is provided
specifically for call_usermodehelper_setup() to call.
call_usermodehelper_setkeys() adjusts the credentials to sport the
supplied keyring as the new session keyring.
(11) SELinux.
SELinux has a number of changes, in addition to those to support the LSM
interface changes mentioned above:
(a) selinux_setprocattr() no longer does its check for whether the
current ptracer can access processes with the new SID inside the lock
that covers getting the ptracer's SID. Whilst this lock ensures that
the check is done with the ptracer pinned, the result is only valid
until the lock is released, so there's no point doing it inside the
lock.
(12) is_single_threaded().
This function has been extracted from selinux_setprocattr() and put into
a file of its own in the lib/ directory as join_session_keyring() now
wants to use it too.
The code in SELinux just checked to see whether a task shared mm_structs
with other tasks (CLONE_VM), but that isn't good enough. We really want
to know if they're part of the same thread group (CLONE_THREAD).
(13) nfsd.
The NFS server daemon now has to use the COW credentials to set the
credentials it is going to use. It really needs to pass the credentials
down to the functions it calls, but it can't do that until other patches
in this series have been applied.
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: James Morris <jmorris@namei.org>
Signed-off-by: James Morris <jmorris@namei.org>
2008-11-13 23:39:23 +00:00
|
|
|
|
|
|
|
abort_change:
|
|
|
|
abort_creds(new);
|
|
|
|
return error;
|
2005-04-16 22:20:36 +00:00
|
|
|
}
|
|
|
|
|
2013-05-22 16:50:35 +00:00
|
|
|
static int selinux_ismaclabel(const char *name)
|
|
|
|
{
|
|
|
|
return (strcmp(name, XATTR_SELINUX_SUFFIX) == 0);
|
|
|
|
}
|
|
|
|
|
2006-08-02 21:12:06 +00:00
|
|
|
static int selinux_secid_to_secctx(u32 secid, char **secdata, u32 *seclen)
|
|
|
|
{
|
|
|
|
return security_sid_to_context(secid, secdata, seclen);
|
|
|
|
}
|
|
|
|
|
2008-04-29 19:52:51 +00:00
|
|
|
static int selinux_secctx_to_secid(const char *secdata, u32 seclen, u32 *secid)
|
2008-01-15 23:47:35 +00:00
|
|
|
{
|
2014-03-07 11:44:19 +00:00
|
|
|
return security_context_to_sid(secdata, seclen, secid, GFP_KERNEL);
|
2008-01-15 23:47:35 +00:00
|
|
|
}
|
|
|
|
|
2006-08-02 21:12:06 +00:00
|
|
|
static void selinux_release_secctx(char *secdata, u32 seclen)
|
|
|
|
{
|
2007-08-01 15:12:58 +00:00
|
|
|
kfree(secdata);
|
2006-08-02 21:12:06 +00:00
|
|
|
}
|
|
|
|
|
2009-09-03 18:25:57 +00:00
|
|
|
/*
|
|
|
|
* called with inode->i_mutex locked
|
|
|
|
*/
|
|
|
|
static int selinux_inode_notifysecctx(struct inode *inode, void *ctx, u32 ctxlen)
|
|
|
|
{
|
|
|
|
return selinux_inode_setsecurity(inode, XATTR_SELINUX_SUFFIX, ctx, ctxlen, 0);
|
|
|
|
}
|
|
|
|
|
|
|
|
/*
|
|
|
|
* called with inode->i_mutex locked
|
|
|
|
*/
|
|
|
|
static int selinux_inode_setsecctx(struct dentry *dentry, void *ctx, u32 ctxlen)
|
|
|
|
{
|
|
|
|
return __vfs_setxattr_noperm(dentry, XATTR_NAME_SELINUX, ctx, ctxlen, 0);
|
|
|
|
}
|
|
|
|
|
|
|
|
static int selinux_inode_getsecctx(struct inode *inode, void **ctx, u32 *ctxlen)
|
|
|
|
{
|
|
|
|
int len = 0;
|
|
|
|
len = selinux_inode_getsecurity(inode, XATTR_SELINUX_SUFFIX,
|
|
|
|
ctx, true);
|
|
|
|
if (len < 0)
|
|
|
|
return len;
|
|
|
|
*ctxlen = len;
|
|
|
|
return 0;
|
|
|
|
}
|
2006-06-22 21:47:17 +00:00
|
|
|
#ifdef CONFIG_KEYS
|
|
|
|
|
CRED: Inaugurate COW credentials
Inaugurate copy-on-write credentials management. This uses RCU to manage the
credentials pointer in the task_struct with respect to accesses by other tasks.
A process may only modify its own credentials, and so does not need locking to
access or modify its own credentials.
A mutex (cred_replace_mutex) is added to the task_struct to control the effect
of PTRACE_ATTACHED on credential calculations, particularly with respect to
execve().
With this patch, the contents of an active credentials struct may not be
changed directly; rather a new set of credentials must be prepared, modified
and committed using something like the following sequence of events:
struct cred *new = prepare_creds();
int ret = blah(new);
if (ret < 0) {
abort_creds(new);
return ret;
}
return commit_creds(new);
There are some exceptions to this rule: the keyrings pointed to by the active
credentials may be instantiated - keyrings violate the COW rule as managing
COW keyrings is tricky, given that it is possible for a task to directly alter
the keys in a keyring in use by another task.
To help enforce this, various pointers to sets of credentials, such as those in
the task_struct, are declared const. The purpose of this is compile-time
discouragement of altering credentials through those pointers. Once a set of
credentials has been made public through one of these pointers, it may not be
modified, except under special circumstances:
(1) Its reference count may incremented and decremented.
(2) The keyrings to which it points may be modified, but not replaced.
The only safe way to modify anything else is to create a replacement and commit
using the functions described in Documentation/credentials.txt (which will be
added by a later patch).
This patch and the preceding patches have been tested with the LTP SELinux
testsuite.
This patch makes several logical sets of alteration:
(1) execve().
This now prepares and commits credentials in various places in the
security code rather than altering the current creds directly.
(2) Temporary credential overrides.
do_coredump() and sys_faccessat() now prepare their own credentials and
temporarily override the ones currently on the acting thread, whilst
preventing interference from other threads by holding cred_replace_mutex
on the thread being dumped.
This will be replaced in a future patch by something that hands down the
credentials directly to the functions being called, rather than altering
the task's objective credentials.
(3) LSM interface.
A number of functions have been changed, added or removed:
(*) security_capset_check(), ->capset_check()
(*) security_capset_set(), ->capset_set()
Removed in favour of security_capset().
(*) security_capset(), ->capset()
New. This is passed a pointer to the new creds, a pointer to the old
creds and the proposed capability sets. It should fill in the new
creds or return an error. All pointers, barring the pointer to the
new creds, are now const.
(*) security_bprm_apply_creds(), ->bprm_apply_creds()
Changed; now returns a value, which will cause the process to be
killed if it's an error.
(*) security_task_alloc(), ->task_alloc_security()
Removed in favour of security_prepare_creds().
(*) security_cred_free(), ->cred_free()
New. Free security data attached to cred->security.
(*) security_prepare_creds(), ->cred_prepare()
New. Duplicate any security data attached to cred->security.
(*) security_commit_creds(), ->cred_commit()
New. Apply any security effects for the upcoming installation of new
security by commit_creds().
(*) security_task_post_setuid(), ->task_post_setuid()
Removed in favour of security_task_fix_setuid().
(*) security_task_fix_setuid(), ->task_fix_setuid()
Fix up the proposed new credentials for setuid(). This is used by
cap_set_fix_setuid() to implicitly adjust capabilities in line with
setuid() changes. Changes are made to the new credentials, rather
than the task itself as in security_task_post_setuid().
(*) security_task_reparent_to_init(), ->task_reparent_to_init()
Removed. Instead the task being reparented to init is referred
directly to init's credentials.
NOTE! This results in the loss of some state: SELinux's osid no
longer records the sid of the thread that forked it.
(*) security_key_alloc(), ->key_alloc()
(*) security_key_permission(), ->key_permission()
Changed. These now take cred pointers rather than task pointers to
refer to the security context.
(4) sys_capset().
This has been simplified and uses less locking. The LSM functions it
calls have been merged.
(5) reparent_to_kthreadd().
This gives the current thread the same credentials as init by simply using
commit_thread() to point that way.
(6) __sigqueue_alloc() and switch_uid()
__sigqueue_alloc() can't stop the target task from changing its creds
beneath it, so this function gets a reference to the currently applicable
user_struct which it then passes into the sigqueue struct it returns if
successful.
switch_uid() is now called from commit_creds(), and possibly should be
folded into that. commit_creds() should take care of protecting
__sigqueue_alloc().
(7) [sg]et[ug]id() and co and [sg]et_current_groups.
The set functions now all use prepare_creds(), commit_creds() and
abort_creds() to build and check a new set of credentials before applying
it.
security_task_set[ug]id() is called inside the prepared section. This
guarantees that nothing else will affect the creds until we've finished.
The calling of set_dumpable() has been moved into commit_creds().
Much of the functionality of set_user() has been moved into
commit_creds().
The get functions all simply access the data directly.
(8) security_task_prctl() and cap_task_prctl().
security_task_prctl() has been modified to return -ENOSYS if it doesn't
want to handle a function, or otherwise return the return value directly
rather than through an argument.
Additionally, cap_task_prctl() now prepares a new set of credentials, even
if it doesn't end up using it.
(9) Keyrings.
A number of changes have been made to the keyrings code:
(a) switch_uid_keyring(), copy_keys(), exit_keys() and suid_keys() have
all been dropped and built in to the credentials functions directly.
They may want separating out again later.
(b) key_alloc() and search_process_keyrings() now take a cred pointer
rather than a task pointer to specify the security context.
(c) copy_creds() gives a new thread within the same thread group a new
thread keyring if its parent had one, otherwise it discards the thread
keyring.
(d) The authorisation key now points directly to the credentials to extend
the search into rather pointing to the task that carries them.
(e) Installing thread, process or session keyrings causes a new set of
credentials to be created, even though it's not strictly necessary for
process or session keyrings (they're shared).
(10) Usermode helper.
The usermode helper code now carries a cred struct pointer in its
subprocess_info struct instead of a new session keyring pointer. This set
of credentials is derived from init_cred and installed on the new process
after it has been cloned.
call_usermodehelper_setup() allocates the new credentials and
call_usermodehelper_freeinfo() discards them if they haven't been used. A
special cred function (prepare_usermodeinfo_creds()) is provided
specifically for call_usermodehelper_setup() to call.
call_usermodehelper_setkeys() adjusts the credentials to sport the
supplied keyring as the new session keyring.
(11) SELinux.
SELinux has a number of changes, in addition to those to support the LSM
interface changes mentioned above:
(a) selinux_setprocattr() no longer does its check for whether the
current ptracer can access processes with the new SID inside the lock
that covers getting the ptracer's SID. Whilst this lock ensures that
the check is done with the ptracer pinned, the result is only valid
until the lock is released, so there's no point doing it inside the
lock.
(12) is_single_threaded().
This function has been extracted from selinux_setprocattr() and put into
a file of its own in the lib/ directory as join_session_keyring() now
wants to use it too.
The code in SELinux just checked to see whether a task shared mm_structs
with other tasks (CLONE_VM), but that isn't good enough. We really want
to know if they're part of the same thread group (CLONE_THREAD).
(13) nfsd.
The NFS server daemon now has to use the COW credentials to set the
credentials it is going to use. It really needs to pass the credentials
down to the functions it calls, but it can't do that until other patches
in this series have been applied.
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: James Morris <jmorris@namei.org>
Signed-off-by: James Morris <jmorris@namei.org>
2008-11-13 23:39:23 +00:00
|
|
|
static int selinux_key_alloc(struct key *k, const struct cred *cred,
|
2006-06-26 07:24:50 +00:00
|
|
|
unsigned long flags)
|
2006-06-22 21:47:17 +00:00
|
|
|
{
|
CRED: Inaugurate COW credentials
Inaugurate copy-on-write credentials management. This uses RCU to manage the
credentials pointer in the task_struct with respect to accesses by other tasks.
A process may only modify its own credentials, and so does not need locking to
access or modify its own credentials.
A mutex (cred_replace_mutex) is added to the task_struct to control the effect
of PTRACE_ATTACHED on credential calculations, particularly with respect to
execve().
With this patch, the contents of an active credentials struct may not be
changed directly; rather a new set of credentials must be prepared, modified
and committed using something like the following sequence of events:
struct cred *new = prepare_creds();
int ret = blah(new);
if (ret < 0) {
abort_creds(new);
return ret;
}
return commit_creds(new);
There are some exceptions to this rule: the keyrings pointed to by the active
credentials may be instantiated - keyrings violate the COW rule as managing
COW keyrings is tricky, given that it is possible for a task to directly alter
the keys in a keyring in use by another task.
To help enforce this, various pointers to sets of credentials, such as those in
the task_struct, are declared const. The purpose of this is compile-time
discouragement of altering credentials through those pointers. Once a set of
credentials has been made public through one of these pointers, it may not be
modified, except under special circumstances:
(1) Its reference count may incremented and decremented.
(2) The keyrings to which it points may be modified, but not replaced.
The only safe way to modify anything else is to create a replacement and commit
using the functions described in Documentation/credentials.txt (which will be
added by a later patch).
This patch and the preceding patches have been tested with the LTP SELinux
testsuite.
This patch makes several logical sets of alteration:
(1) execve().
This now prepares and commits credentials in various places in the
security code rather than altering the current creds directly.
(2) Temporary credential overrides.
do_coredump() and sys_faccessat() now prepare their own credentials and
temporarily override the ones currently on the acting thread, whilst
preventing interference from other threads by holding cred_replace_mutex
on the thread being dumped.
This will be replaced in a future patch by something that hands down the
credentials directly to the functions being called, rather than altering
the task's objective credentials.
(3) LSM interface.
A number of functions have been changed, added or removed:
(*) security_capset_check(), ->capset_check()
(*) security_capset_set(), ->capset_set()
Removed in favour of security_capset().
(*) security_capset(), ->capset()
New. This is passed a pointer to the new creds, a pointer to the old
creds and the proposed capability sets. It should fill in the new
creds or return an error. All pointers, barring the pointer to the
new creds, are now const.
(*) security_bprm_apply_creds(), ->bprm_apply_creds()
Changed; now returns a value, which will cause the process to be
killed if it's an error.
(*) security_task_alloc(), ->task_alloc_security()
Removed in favour of security_prepare_creds().
(*) security_cred_free(), ->cred_free()
New. Free security data attached to cred->security.
(*) security_prepare_creds(), ->cred_prepare()
New. Duplicate any security data attached to cred->security.
(*) security_commit_creds(), ->cred_commit()
New. Apply any security effects for the upcoming installation of new
security by commit_creds().
(*) security_task_post_setuid(), ->task_post_setuid()
Removed in favour of security_task_fix_setuid().
(*) security_task_fix_setuid(), ->task_fix_setuid()
Fix up the proposed new credentials for setuid(). This is used by
cap_set_fix_setuid() to implicitly adjust capabilities in line with
setuid() changes. Changes are made to the new credentials, rather
than the task itself as in security_task_post_setuid().
(*) security_task_reparent_to_init(), ->task_reparent_to_init()
Removed. Instead the task being reparented to init is referred
directly to init's credentials.
NOTE! This results in the loss of some state: SELinux's osid no
longer records the sid of the thread that forked it.
(*) security_key_alloc(), ->key_alloc()
(*) security_key_permission(), ->key_permission()
Changed. These now take cred pointers rather than task pointers to
refer to the security context.
(4) sys_capset().
This has been simplified and uses less locking. The LSM functions it
calls have been merged.
(5) reparent_to_kthreadd().
This gives the current thread the same credentials as init by simply using
commit_thread() to point that way.
(6) __sigqueue_alloc() and switch_uid()
__sigqueue_alloc() can't stop the target task from changing its creds
beneath it, so this function gets a reference to the currently applicable
user_struct which it then passes into the sigqueue struct it returns if
successful.
switch_uid() is now called from commit_creds(), and possibly should be
folded into that. commit_creds() should take care of protecting
__sigqueue_alloc().
(7) [sg]et[ug]id() and co and [sg]et_current_groups.
The set functions now all use prepare_creds(), commit_creds() and
abort_creds() to build and check a new set of credentials before applying
it.
security_task_set[ug]id() is called inside the prepared section. This
guarantees that nothing else will affect the creds until we've finished.
The calling of set_dumpable() has been moved into commit_creds().
Much of the functionality of set_user() has been moved into
commit_creds().
The get functions all simply access the data directly.
(8) security_task_prctl() and cap_task_prctl().
security_task_prctl() has been modified to return -ENOSYS if it doesn't
want to handle a function, or otherwise return the return value directly
rather than through an argument.
Additionally, cap_task_prctl() now prepares a new set of credentials, even
if it doesn't end up using it.
(9) Keyrings.
A number of changes have been made to the keyrings code:
(a) switch_uid_keyring(), copy_keys(), exit_keys() and suid_keys() have
all been dropped and built in to the credentials functions directly.
They may want separating out again later.
(b) key_alloc() and search_process_keyrings() now take a cred pointer
rather than a task pointer to specify the security context.
(c) copy_creds() gives a new thread within the same thread group a new
thread keyring if its parent had one, otherwise it discards the thread
keyring.
(d) The authorisation key now points directly to the credentials to extend
the search into rather pointing to the task that carries them.
(e) Installing thread, process or session keyrings causes a new set of
credentials to be created, even though it's not strictly necessary for
process or session keyrings (they're shared).
(10) Usermode helper.
The usermode helper code now carries a cred struct pointer in its
subprocess_info struct instead of a new session keyring pointer. This set
of credentials is derived from init_cred and installed on the new process
after it has been cloned.
call_usermodehelper_setup() allocates the new credentials and
call_usermodehelper_freeinfo() discards them if they haven't been used. A
special cred function (prepare_usermodeinfo_creds()) is provided
specifically for call_usermodehelper_setup() to call.
call_usermodehelper_setkeys() adjusts the credentials to sport the
supplied keyring as the new session keyring.
(11) SELinux.
SELinux has a number of changes, in addition to those to support the LSM
interface changes mentioned above:
(a) selinux_setprocattr() no longer does its check for whether the
current ptracer can access processes with the new SID inside the lock
that covers getting the ptracer's SID. Whilst this lock ensures that
the check is done with the ptracer pinned, the result is only valid
until the lock is released, so there's no point doing it inside the
lock.
(12) is_single_threaded().
This function has been extracted from selinux_setprocattr() and put into
a file of its own in the lib/ directory as join_session_keyring() now
wants to use it too.
The code in SELinux just checked to see whether a task shared mm_structs
with other tasks (CLONE_VM), but that isn't good enough. We really want
to know if they're part of the same thread group (CLONE_THREAD).
(13) nfsd.
The NFS server daemon now has to use the COW credentials to set the
credentials it is going to use. It really needs to pass the credentials
down to the functions it calls, but it can't do that until other patches
in this series have been applied.
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: James Morris <jmorris@namei.org>
Signed-off-by: James Morris <jmorris@namei.org>
2008-11-13 23:39:23 +00:00
|
|
|
const struct task_security_struct *tsec;
|
2006-06-22 21:47:17 +00:00
|
|
|
struct key_security_struct *ksec;
|
|
|
|
|
|
|
|
ksec = kzalloc(sizeof(struct key_security_struct), GFP_KERNEL);
|
|
|
|
if (!ksec)
|
|
|
|
return -ENOMEM;
|
|
|
|
|
CRED: Inaugurate COW credentials
Inaugurate copy-on-write credentials management. This uses RCU to manage the
credentials pointer in the task_struct with respect to accesses by other tasks.
A process may only modify its own credentials, and so does not need locking to
access or modify its own credentials.
A mutex (cred_replace_mutex) is added to the task_struct to control the effect
of PTRACE_ATTACHED on credential calculations, particularly with respect to
execve().
With this patch, the contents of an active credentials struct may not be
changed directly; rather a new set of credentials must be prepared, modified
and committed using something like the following sequence of events:
struct cred *new = prepare_creds();
int ret = blah(new);
if (ret < 0) {
abort_creds(new);
return ret;
}
return commit_creds(new);
There are some exceptions to this rule: the keyrings pointed to by the active
credentials may be instantiated - keyrings violate the COW rule as managing
COW keyrings is tricky, given that it is possible for a task to directly alter
the keys in a keyring in use by another task.
To help enforce this, various pointers to sets of credentials, such as those in
the task_struct, are declared const. The purpose of this is compile-time
discouragement of altering credentials through those pointers. Once a set of
credentials has been made public through one of these pointers, it may not be
modified, except under special circumstances:
(1) Its reference count may incremented and decremented.
(2) The keyrings to which it points may be modified, but not replaced.
The only safe way to modify anything else is to create a replacement and commit
using the functions described in Documentation/credentials.txt (which will be
added by a later patch).
This patch and the preceding patches have been tested with the LTP SELinux
testsuite.
This patch makes several logical sets of alteration:
(1) execve().
This now prepares and commits credentials in various places in the
security code rather than altering the current creds directly.
(2) Temporary credential overrides.
do_coredump() and sys_faccessat() now prepare their own credentials and
temporarily override the ones currently on the acting thread, whilst
preventing interference from other threads by holding cred_replace_mutex
on the thread being dumped.
This will be replaced in a future patch by something that hands down the
credentials directly to the functions being called, rather than altering
the task's objective credentials.
(3) LSM interface.
A number of functions have been changed, added or removed:
(*) security_capset_check(), ->capset_check()
(*) security_capset_set(), ->capset_set()
Removed in favour of security_capset().
(*) security_capset(), ->capset()
New. This is passed a pointer to the new creds, a pointer to the old
creds and the proposed capability sets. It should fill in the new
creds or return an error. All pointers, barring the pointer to the
new creds, are now const.
(*) security_bprm_apply_creds(), ->bprm_apply_creds()
Changed; now returns a value, which will cause the process to be
killed if it's an error.
(*) security_task_alloc(), ->task_alloc_security()
Removed in favour of security_prepare_creds().
(*) security_cred_free(), ->cred_free()
New. Free security data attached to cred->security.
(*) security_prepare_creds(), ->cred_prepare()
New. Duplicate any security data attached to cred->security.
(*) security_commit_creds(), ->cred_commit()
New. Apply any security effects for the upcoming installation of new
security by commit_creds().
(*) security_task_post_setuid(), ->task_post_setuid()
Removed in favour of security_task_fix_setuid().
(*) security_task_fix_setuid(), ->task_fix_setuid()
Fix up the proposed new credentials for setuid(). This is used by
cap_set_fix_setuid() to implicitly adjust capabilities in line with
setuid() changes. Changes are made to the new credentials, rather
than the task itself as in security_task_post_setuid().
(*) security_task_reparent_to_init(), ->task_reparent_to_init()
Removed. Instead the task being reparented to init is referred
directly to init's credentials.
NOTE! This results in the loss of some state: SELinux's osid no
longer records the sid of the thread that forked it.
(*) security_key_alloc(), ->key_alloc()
(*) security_key_permission(), ->key_permission()
Changed. These now take cred pointers rather than task pointers to
refer to the security context.
(4) sys_capset().
This has been simplified and uses less locking. The LSM functions it
calls have been merged.
(5) reparent_to_kthreadd().
This gives the current thread the same credentials as init by simply using
commit_thread() to point that way.
(6) __sigqueue_alloc() and switch_uid()
__sigqueue_alloc() can't stop the target task from changing its creds
beneath it, so this function gets a reference to the currently applicable
user_struct which it then passes into the sigqueue struct it returns if
successful.
switch_uid() is now called from commit_creds(), and possibly should be
folded into that. commit_creds() should take care of protecting
__sigqueue_alloc().
(7) [sg]et[ug]id() and co and [sg]et_current_groups.
The set functions now all use prepare_creds(), commit_creds() and
abort_creds() to build and check a new set of credentials before applying
it.
security_task_set[ug]id() is called inside the prepared section. This
guarantees that nothing else will affect the creds until we've finished.
The calling of set_dumpable() has been moved into commit_creds().
Much of the functionality of set_user() has been moved into
commit_creds().
The get functions all simply access the data directly.
(8) security_task_prctl() and cap_task_prctl().
security_task_prctl() has been modified to return -ENOSYS if it doesn't
want to handle a function, or otherwise return the return value directly
rather than through an argument.
Additionally, cap_task_prctl() now prepares a new set of credentials, even
if it doesn't end up using it.
(9) Keyrings.
A number of changes have been made to the keyrings code:
(a) switch_uid_keyring(), copy_keys(), exit_keys() and suid_keys() have
all been dropped and built in to the credentials functions directly.
They may want separating out again later.
(b) key_alloc() and search_process_keyrings() now take a cred pointer
rather than a task pointer to specify the security context.
(c) copy_creds() gives a new thread within the same thread group a new
thread keyring if its parent had one, otherwise it discards the thread
keyring.
(d) The authorisation key now points directly to the credentials to extend
the search into rather pointing to the task that carries them.
(e) Installing thread, process or session keyrings causes a new set of
credentials to be created, even though it's not strictly necessary for
process or session keyrings (they're shared).
(10) Usermode helper.
The usermode helper code now carries a cred struct pointer in its
subprocess_info struct instead of a new session keyring pointer. This set
of credentials is derived from init_cred and installed on the new process
after it has been cloned.
call_usermodehelper_setup() allocates the new credentials and
call_usermodehelper_freeinfo() discards them if they haven't been used. A
special cred function (prepare_usermodeinfo_creds()) is provided
specifically for call_usermodehelper_setup() to call.
call_usermodehelper_setkeys() adjusts the credentials to sport the
supplied keyring as the new session keyring.
(11) SELinux.
SELinux has a number of changes, in addition to those to support the LSM
interface changes mentioned above:
(a) selinux_setprocattr() no longer does its check for whether the
current ptracer can access processes with the new SID inside the lock
that covers getting the ptracer's SID. Whilst this lock ensures that
the check is done with the ptracer pinned, the result is only valid
until the lock is released, so there's no point doing it inside the
lock.
(12) is_single_threaded().
This function has been extracted from selinux_setprocattr() and put into
a file of its own in the lib/ directory as join_session_keyring() now
wants to use it too.
The code in SELinux just checked to see whether a task shared mm_structs
with other tasks (CLONE_VM), but that isn't good enough. We really want
to know if they're part of the same thread group (CLONE_THREAD).
(13) nfsd.
The NFS server daemon now has to use the COW credentials to set the
credentials it is going to use. It really needs to pass the credentials
down to the functions it calls, but it can't do that until other patches
in this series have been applied.
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: James Morris <jmorris@namei.org>
Signed-off-by: James Morris <jmorris@namei.org>
2008-11-13 23:39:23 +00:00
|
|
|
tsec = cred->security;
|
|
|
|
if (tsec->keycreate_sid)
|
|
|
|
ksec->sid = tsec->keycreate_sid;
|
2006-06-26 07:24:57 +00:00
|
|
|
else
|
CRED: Inaugurate COW credentials
Inaugurate copy-on-write credentials management. This uses RCU to manage the
credentials pointer in the task_struct with respect to accesses by other tasks.
A process may only modify its own credentials, and so does not need locking to
access or modify its own credentials.
A mutex (cred_replace_mutex) is added to the task_struct to control the effect
of PTRACE_ATTACHED on credential calculations, particularly with respect to
execve().
With this patch, the contents of an active credentials struct may not be
changed directly; rather a new set of credentials must be prepared, modified
and committed using something like the following sequence of events:
struct cred *new = prepare_creds();
int ret = blah(new);
if (ret < 0) {
abort_creds(new);
return ret;
}
return commit_creds(new);
There are some exceptions to this rule: the keyrings pointed to by the active
credentials may be instantiated - keyrings violate the COW rule as managing
COW keyrings is tricky, given that it is possible for a task to directly alter
the keys in a keyring in use by another task.
To help enforce this, various pointers to sets of credentials, such as those in
the task_struct, are declared const. The purpose of this is compile-time
discouragement of altering credentials through those pointers. Once a set of
credentials has been made public through one of these pointers, it may not be
modified, except under special circumstances:
(1) Its reference count may incremented and decremented.
(2) The keyrings to which it points may be modified, but not replaced.
The only safe way to modify anything else is to create a replacement and commit
using the functions described in Documentation/credentials.txt (which will be
added by a later patch).
This patch and the preceding patches have been tested with the LTP SELinux
testsuite.
This patch makes several logical sets of alteration:
(1) execve().
This now prepares and commits credentials in various places in the
security code rather than altering the current creds directly.
(2) Temporary credential overrides.
do_coredump() and sys_faccessat() now prepare their own credentials and
temporarily override the ones currently on the acting thread, whilst
preventing interference from other threads by holding cred_replace_mutex
on the thread being dumped.
This will be replaced in a future patch by something that hands down the
credentials directly to the functions being called, rather than altering
the task's objective credentials.
(3) LSM interface.
A number of functions have been changed, added or removed:
(*) security_capset_check(), ->capset_check()
(*) security_capset_set(), ->capset_set()
Removed in favour of security_capset().
(*) security_capset(), ->capset()
New. This is passed a pointer to the new creds, a pointer to the old
creds and the proposed capability sets. It should fill in the new
creds or return an error. All pointers, barring the pointer to the
new creds, are now const.
(*) security_bprm_apply_creds(), ->bprm_apply_creds()
Changed; now returns a value, which will cause the process to be
killed if it's an error.
(*) security_task_alloc(), ->task_alloc_security()
Removed in favour of security_prepare_creds().
(*) security_cred_free(), ->cred_free()
New. Free security data attached to cred->security.
(*) security_prepare_creds(), ->cred_prepare()
New. Duplicate any security data attached to cred->security.
(*) security_commit_creds(), ->cred_commit()
New. Apply any security effects for the upcoming installation of new
security by commit_creds().
(*) security_task_post_setuid(), ->task_post_setuid()
Removed in favour of security_task_fix_setuid().
(*) security_task_fix_setuid(), ->task_fix_setuid()
Fix up the proposed new credentials for setuid(). This is used by
cap_set_fix_setuid() to implicitly adjust capabilities in line with
setuid() changes. Changes are made to the new credentials, rather
than the task itself as in security_task_post_setuid().
(*) security_task_reparent_to_init(), ->task_reparent_to_init()
Removed. Instead the task being reparented to init is referred
directly to init's credentials.
NOTE! This results in the loss of some state: SELinux's osid no
longer records the sid of the thread that forked it.
(*) security_key_alloc(), ->key_alloc()
(*) security_key_permission(), ->key_permission()
Changed. These now take cred pointers rather than task pointers to
refer to the security context.
(4) sys_capset().
This has been simplified and uses less locking. The LSM functions it
calls have been merged.
(5) reparent_to_kthreadd().
This gives the current thread the same credentials as init by simply using
commit_thread() to point that way.
(6) __sigqueue_alloc() and switch_uid()
__sigqueue_alloc() can't stop the target task from changing its creds
beneath it, so this function gets a reference to the currently applicable
user_struct which it then passes into the sigqueue struct it returns if
successful.
switch_uid() is now called from commit_creds(), and possibly should be
folded into that. commit_creds() should take care of protecting
__sigqueue_alloc().
(7) [sg]et[ug]id() and co and [sg]et_current_groups.
The set functions now all use prepare_creds(), commit_creds() and
abort_creds() to build and check a new set of credentials before applying
it.
security_task_set[ug]id() is called inside the prepared section. This
guarantees that nothing else will affect the creds until we've finished.
The calling of set_dumpable() has been moved into commit_creds().
Much of the functionality of set_user() has been moved into
commit_creds().
The get functions all simply access the data directly.
(8) security_task_prctl() and cap_task_prctl().
security_task_prctl() has been modified to return -ENOSYS if it doesn't
want to handle a function, or otherwise return the return value directly
rather than through an argument.
Additionally, cap_task_prctl() now prepares a new set of credentials, even
if it doesn't end up using it.
(9) Keyrings.
A number of changes have been made to the keyrings code:
(a) switch_uid_keyring(), copy_keys(), exit_keys() and suid_keys() have
all been dropped and built in to the credentials functions directly.
They may want separating out again later.
(b) key_alloc() and search_process_keyrings() now take a cred pointer
rather than a task pointer to specify the security context.
(c) copy_creds() gives a new thread within the same thread group a new
thread keyring if its parent had one, otherwise it discards the thread
keyring.
(d) The authorisation key now points directly to the credentials to extend
the search into rather pointing to the task that carries them.
(e) Installing thread, process or session keyrings causes a new set of
credentials to be created, even though it's not strictly necessary for
process or session keyrings (they're shared).
(10) Usermode helper.
The usermode helper code now carries a cred struct pointer in its
subprocess_info struct instead of a new session keyring pointer. This set
of credentials is derived from init_cred and installed on the new process
after it has been cloned.
call_usermodehelper_setup() allocates the new credentials and
call_usermodehelper_freeinfo() discards them if they haven't been used. A
special cred function (prepare_usermodeinfo_creds()) is provided
specifically for call_usermodehelper_setup() to call.
call_usermodehelper_setkeys() adjusts the credentials to sport the
supplied keyring as the new session keyring.
(11) SELinux.
SELinux has a number of changes, in addition to those to support the LSM
interface changes mentioned above:
(a) selinux_setprocattr() no longer does its check for whether the
current ptracer can access processes with the new SID inside the lock
that covers getting the ptracer's SID. Whilst this lock ensures that
the check is done with the ptracer pinned, the result is only valid
until the lock is released, so there's no point doing it inside the
lock.
(12) is_single_threaded().
This function has been extracted from selinux_setprocattr() and put into
a file of its own in the lib/ directory as join_session_keyring() now
wants to use it too.
The code in SELinux just checked to see whether a task shared mm_structs
with other tasks (CLONE_VM), but that isn't good enough. We really want
to know if they're part of the same thread group (CLONE_THREAD).
(13) nfsd.
The NFS server daemon now has to use the COW credentials to set the
credentials it is going to use. It really needs to pass the credentials
down to the functions it calls, but it can't do that until other patches
in this series have been applied.
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: James Morris <jmorris@namei.org>
Signed-off-by: James Morris <jmorris@namei.org>
2008-11-13 23:39:23 +00:00
|
|
|
ksec->sid = tsec->sid;
|
2006-06-22 21:47:17 +00:00
|
|
|
|
2008-11-13 23:39:19 +00:00
|
|
|
k->security = ksec;
|
2006-06-22 21:47:17 +00:00
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
|
|
|
static void selinux_key_free(struct key *k)
|
|
|
|
{
|
|
|
|
struct key_security_struct *ksec = k->security;
|
|
|
|
|
|
|
|
k->security = NULL;
|
|
|
|
kfree(ksec);
|
|
|
|
}
|
|
|
|
|
|
|
|
static int selinux_key_permission(key_ref_t key_ref,
|
CRED: Inaugurate COW credentials
Inaugurate copy-on-write credentials management. This uses RCU to manage the
credentials pointer in the task_struct with respect to accesses by other tasks.
A process may only modify its own credentials, and so does not need locking to
access or modify its own credentials.
A mutex (cred_replace_mutex) is added to the task_struct to control the effect
of PTRACE_ATTACHED on credential calculations, particularly with respect to
execve().
With this patch, the contents of an active credentials struct may not be
changed directly; rather a new set of credentials must be prepared, modified
and committed using something like the following sequence of events:
struct cred *new = prepare_creds();
int ret = blah(new);
if (ret < 0) {
abort_creds(new);
return ret;
}
return commit_creds(new);
There are some exceptions to this rule: the keyrings pointed to by the active
credentials may be instantiated - keyrings violate the COW rule as managing
COW keyrings is tricky, given that it is possible for a task to directly alter
the keys in a keyring in use by another task.
To help enforce this, various pointers to sets of credentials, such as those in
the task_struct, are declared const. The purpose of this is compile-time
discouragement of altering credentials through those pointers. Once a set of
credentials has been made public through one of these pointers, it may not be
modified, except under special circumstances:
(1) Its reference count may incremented and decremented.
(2) The keyrings to which it points may be modified, but not replaced.
The only safe way to modify anything else is to create a replacement and commit
using the functions described in Documentation/credentials.txt (which will be
added by a later patch).
This patch and the preceding patches have been tested with the LTP SELinux
testsuite.
This patch makes several logical sets of alteration:
(1) execve().
This now prepares and commits credentials in various places in the
security code rather than altering the current creds directly.
(2) Temporary credential overrides.
do_coredump() and sys_faccessat() now prepare their own credentials and
temporarily override the ones currently on the acting thread, whilst
preventing interference from other threads by holding cred_replace_mutex
on the thread being dumped.
This will be replaced in a future patch by something that hands down the
credentials directly to the functions being called, rather than altering
the task's objective credentials.
(3) LSM interface.
A number of functions have been changed, added or removed:
(*) security_capset_check(), ->capset_check()
(*) security_capset_set(), ->capset_set()
Removed in favour of security_capset().
(*) security_capset(), ->capset()
New. This is passed a pointer to the new creds, a pointer to the old
creds and the proposed capability sets. It should fill in the new
creds or return an error. All pointers, barring the pointer to the
new creds, are now const.
(*) security_bprm_apply_creds(), ->bprm_apply_creds()
Changed; now returns a value, which will cause the process to be
killed if it's an error.
(*) security_task_alloc(), ->task_alloc_security()
Removed in favour of security_prepare_creds().
(*) security_cred_free(), ->cred_free()
New. Free security data attached to cred->security.
(*) security_prepare_creds(), ->cred_prepare()
New. Duplicate any security data attached to cred->security.
(*) security_commit_creds(), ->cred_commit()
New. Apply any security effects for the upcoming installation of new
security by commit_creds().
(*) security_task_post_setuid(), ->task_post_setuid()
Removed in favour of security_task_fix_setuid().
(*) security_task_fix_setuid(), ->task_fix_setuid()
Fix up the proposed new credentials for setuid(). This is used by
cap_set_fix_setuid() to implicitly adjust capabilities in line with
setuid() changes. Changes are made to the new credentials, rather
than the task itself as in security_task_post_setuid().
(*) security_task_reparent_to_init(), ->task_reparent_to_init()
Removed. Instead the task being reparented to init is referred
directly to init's credentials.
NOTE! This results in the loss of some state: SELinux's osid no
longer records the sid of the thread that forked it.
(*) security_key_alloc(), ->key_alloc()
(*) security_key_permission(), ->key_permission()
Changed. These now take cred pointers rather than task pointers to
refer to the security context.
(4) sys_capset().
This has been simplified and uses less locking. The LSM functions it
calls have been merged.
(5) reparent_to_kthreadd().
This gives the current thread the same credentials as init by simply using
commit_thread() to point that way.
(6) __sigqueue_alloc() and switch_uid()
__sigqueue_alloc() can't stop the target task from changing its creds
beneath it, so this function gets a reference to the currently applicable
user_struct which it then passes into the sigqueue struct it returns if
successful.
switch_uid() is now called from commit_creds(), and possibly should be
folded into that. commit_creds() should take care of protecting
__sigqueue_alloc().
(7) [sg]et[ug]id() and co and [sg]et_current_groups.
The set functions now all use prepare_creds(), commit_creds() and
abort_creds() to build and check a new set of credentials before applying
it.
security_task_set[ug]id() is called inside the prepared section. This
guarantees that nothing else will affect the creds until we've finished.
The calling of set_dumpable() has been moved into commit_creds().
Much of the functionality of set_user() has been moved into
commit_creds().
The get functions all simply access the data directly.
(8) security_task_prctl() and cap_task_prctl().
security_task_prctl() has been modified to return -ENOSYS if it doesn't
want to handle a function, or otherwise return the return value directly
rather than through an argument.
Additionally, cap_task_prctl() now prepares a new set of credentials, even
if it doesn't end up using it.
(9) Keyrings.
A number of changes have been made to the keyrings code:
(a) switch_uid_keyring(), copy_keys(), exit_keys() and suid_keys() have
all been dropped and built in to the credentials functions directly.
They may want separating out again later.
(b) key_alloc() and search_process_keyrings() now take a cred pointer
rather than a task pointer to specify the security context.
(c) copy_creds() gives a new thread within the same thread group a new
thread keyring if its parent had one, otherwise it discards the thread
keyring.
(d) The authorisation key now points directly to the credentials to extend
the search into rather pointing to the task that carries them.
(e) Installing thread, process or session keyrings causes a new set of
credentials to be created, even though it's not strictly necessary for
process or session keyrings (they're shared).
(10) Usermode helper.
The usermode helper code now carries a cred struct pointer in its
subprocess_info struct instead of a new session keyring pointer. This set
of credentials is derived from init_cred and installed on the new process
after it has been cloned.
call_usermodehelper_setup() allocates the new credentials and
call_usermodehelper_freeinfo() discards them if they haven't been used. A
special cred function (prepare_usermodeinfo_creds()) is provided
specifically for call_usermodehelper_setup() to call.
call_usermodehelper_setkeys() adjusts the credentials to sport the
supplied keyring as the new session keyring.
(11) SELinux.
SELinux has a number of changes, in addition to those to support the LSM
interface changes mentioned above:
(a) selinux_setprocattr() no longer does its check for whether the
current ptracer can access processes with the new SID inside the lock
that covers getting the ptracer's SID. Whilst this lock ensures that
the check is done with the ptracer pinned, the result is only valid
until the lock is released, so there's no point doing it inside the
lock.
(12) is_single_threaded().
This function has been extracted from selinux_setprocattr() and put into
a file of its own in the lib/ directory as join_session_keyring() now
wants to use it too.
The code in SELinux just checked to see whether a task shared mm_structs
with other tasks (CLONE_VM), but that isn't good enough. We really want
to know if they're part of the same thread group (CLONE_THREAD).
(13) nfsd.
The NFS server daemon now has to use the COW credentials to set the
credentials it is going to use. It really needs to pass the credentials
down to the functions it calls, but it can't do that until other patches
in this series have been applied.
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: James Morris <jmorris@namei.org>
Signed-off-by: James Morris <jmorris@namei.org>
2008-11-13 23:39:23 +00:00
|
|
|
const struct cred *cred,
|
|
|
|
key_perm_t perm)
|
2006-06-22 21:47:17 +00:00
|
|
|
{
|
|
|
|
struct key *key;
|
|
|
|
struct key_security_struct *ksec;
|
2008-11-13 23:39:19 +00:00
|
|
|
u32 sid;
|
2006-06-22 21:47:17 +00:00
|
|
|
|
|
|
|
/* if no specific permissions are requested, we skip the
|
|
|
|
permission check. No serious, additional covert channels
|
|
|
|
appear to be created. */
|
|
|
|
if (perm == 0)
|
|
|
|
return 0;
|
|
|
|
|
CRED: Inaugurate COW credentials
Inaugurate copy-on-write credentials management. This uses RCU to manage the
credentials pointer in the task_struct with respect to accesses by other tasks.
A process may only modify its own credentials, and so does not need locking to
access or modify its own credentials.
A mutex (cred_replace_mutex) is added to the task_struct to control the effect
of PTRACE_ATTACHED on credential calculations, particularly with respect to
execve().
With this patch, the contents of an active credentials struct may not be
changed directly; rather a new set of credentials must be prepared, modified
and committed using something like the following sequence of events:
struct cred *new = prepare_creds();
int ret = blah(new);
if (ret < 0) {
abort_creds(new);
return ret;
}
return commit_creds(new);
There are some exceptions to this rule: the keyrings pointed to by the active
credentials may be instantiated - keyrings violate the COW rule as managing
COW keyrings is tricky, given that it is possible for a task to directly alter
the keys in a keyring in use by another task.
To help enforce this, various pointers to sets of credentials, such as those in
the task_struct, are declared const. The purpose of this is compile-time
discouragement of altering credentials through those pointers. Once a set of
credentials has been made public through one of these pointers, it may not be
modified, except under special circumstances:
(1) Its reference count may incremented and decremented.
(2) The keyrings to which it points may be modified, but not replaced.
The only safe way to modify anything else is to create a replacement and commit
using the functions described in Documentation/credentials.txt (which will be
added by a later patch).
This patch and the preceding patches have been tested with the LTP SELinux
testsuite.
This patch makes several logical sets of alteration:
(1) execve().
This now prepares and commits credentials in various places in the
security code rather than altering the current creds directly.
(2) Temporary credential overrides.
do_coredump() and sys_faccessat() now prepare their own credentials and
temporarily override the ones currently on the acting thread, whilst
preventing interference from other threads by holding cred_replace_mutex
on the thread being dumped.
This will be replaced in a future patch by something that hands down the
credentials directly to the functions being called, rather than altering
the task's objective credentials.
(3) LSM interface.
A number of functions have been changed, added or removed:
(*) security_capset_check(), ->capset_check()
(*) security_capset_set(), ->capset_set()
Removed in favour of security_capset().
(*) security_capset(), ->capset()
New. This is passed a pointer to the new creds, a pointer to the old
creds and the proposed capability sets. It should fill in the new
creds or return an error. All pointers, barring the pointer to the
new creds, are now const.
(*) security_bprm_apply_creds(), ->bprm_apply_creds()
Changed; now returns a value, which will cause the process to be
killed if it's an error.
(*) security_task_alloc(), ->task_alloc_security()
Removed in favour of security_prepare_creds().
(*) security_cred_free(), ->cred_free()
New. Free security data attached to cred->security.
(*) security_prepare_creds(), ->cred_prepare()
New. Duplicate any security data attached to cred->security.
(*) security_commit_creds(), ->cred_commit()
New. Apply any security effects for the upcoming installation of new
security by commit_creds().
(*) security_task_post_setuid(), ->task_post_setuid()
Removed in favour of security_task_fix_setuid().
(*) security_task_fix_setuid(), ->task_fix_setuid()
Fix up the proposed new credentials for setuid(). This is used by
cap_set_fix_setuid() to implicitly adjust capabilities in line with
setuid() changes. Changes are made to the new credentials, rather
than the task itself as in security_task_post_setuid().
(*) security_task_reparent_to_init(), ->task_reparent_to_init()
Removed. Instead the task being reparented to init is referred
directly to init's credentials.
NOTE! This results in the loss of some state: SELinux's osid no
longer records the sid of the thread that forked it.
(*) security_key_alloc(), ->key_alloc()
(*) security_key_permission(), ->key_permission()
Changed. These now take cred pointers rather than task pointers to
refer to the security context.
(4) sys_capset().
This has been simplified and uses less locking. The LSM functions it
calls have been merged.
(5) reparent_to_kthreadd().
This gives the current thread the same credentials as init by simply using
commit_thread() to point that way.
(6) __sigqueue_alloc() and switch_uid()
__sigqueue_alloc() can't stop the target task from changing its creds
beneath it, so this function gets a reference to the currently applicable
user_struct which it then passes into the sigqueue struct it returns if
successful.
switch_uid() is now called from commit_creds(), and possibly should be
folded into that. commit_creds() should take care of protecting
__sigqueue_alloc().
(7) [sg]et[ug]id() and co and [sg]et_current_groups.
The set functions now all use prepare_creds(), commit_creds() and
abort_creds() to build and check a new set of credentials before applying
it.
security_task_set[ug]id() is called inside the prepared section. This
guarantees that nothing else will affect the creds until we've finished.
The calling of set_dumpable() has been moved into commit_creds().
Much of the functionality of set_user() has been moved into
commit_creds().
The get functions all simply access the data directly.
(8) security_task_prctl() and cap_task_prctl().
security_task_prctl() has been modified to return -ENOSYS if it doesn't
want to handle a function, or otherwise return the return value directly
rather than through an argument.
Additionally, cap_task_prctl() now prepares a new set of credentials, even
if it doesn't end up using it.
(9) Keyrings.
A number of changes have been made to the keyrings code:
(a) switch_uid_keyring(), copy_keys(), exit_keys() and suid_keys() have
all been dropped and built in to the credentials functions directly.
They may want separating out again later.
(b) key_alloc() and search_process_keyrings() now take a cred pointer
rather than a task pointer to specify the security context.
(c) copy_creds() gives a new thread within the same thread group a new
thread keyring if its parent had one, otherwise it discards the thread
keyring.
(d) The authorisation key now points directly to the credentials to extend
the search into rather pointing to the task that carries them.
(e) Installing thread, process or session keyrings causes a new set of
credentials to be created, even though it's not strictly necessary for
process or session keyrings (they're shared).
(10) Usermode helper.
The usermode helper code now carries a cred struct pointer in its
subprocess_info struct instead of a new session keyring pointer. This set
of credentials is derived from init_cred and installed on the new process
after it has been cloned.
call_usermodehelper_setup() allocates the new credentials and
call_usermodehelper_freeinfo() discards them if they haven't been used. A
special cred function (prepare_usermodeinfo_creds()) is provided
specifically for call_usermodehelper_setup() to call.
call_usermodehelper_setkeys() adjusts the credentials to sport the
supplied keyring as the new session keyring.
(11) SELinux.
SELinux has a number of changes, in addition to those to support the LSM
interface changes mentioned above:
(a) selinux_setprocattr() no longer does its check for whether the
current ptracer can access processes with the new SID inside the lock
that covers getting the ptracer's SID. Whilst this lock ensures that
the check is done with the ptracer pinned, the result is only valid
until the lock is released, so there's no point doing it inside the
lock.
(12) is_single_threaded().
This function has been extracted from selinux_setprocattr() and put into
a file of its own in the lib/ directory as join_session_keyring() now
wants to use it too.
The code in SELinux just checked to see whether a task shared mm_structs
with other tasks (CLONE_VM), but that isn't good enough. We really want
to know if they're part of the same thread group (CLONE_THREAD).
(13) nfsd.
The NFS server daemon now has to use the COW credentials to set the
credentials it is going to use. It really needs to pass the credentials
down to the functions it calls, but it can't do that until other patches
in this series have been applied.
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: James Morris <jmorris@namei.org>
Signed-off-by: James Morris <jmorris@namei.org>
2008-11-13 23:39:23 +00:00
|
|
|
sid = cred_sid(cred);
|
2008-11-13 23:39:19 +00:00
|
|
|
|
|
|
|
key = key_ref_to_ptr(key_ref);
|
|
|
|
ksec = key->security;
|
|
|
|
|
|
|
|
return avc_has_perm(sid, ksec->sid, SECCLASS_KEY, perm, NULL);
|
2006-06-22 21:47:17 +00:00
|
|
|
}
|
|
|
|
|
2008-04-29 08:01:26 +00:00
|
|
|
static int selinux_key_getsecurity(struct key *key, char **_buffer)
|
|
|
|
{
|
|
|
|
struct key_security_struct *ksec = key->security;
|
|
|
|
char *context = NULL;
|
|
|
|
unsigned len;
|
|
|
|
int rc;
|
|
|
|
|
|
|
|
rc = security_sid_to_context(ksec->sid, &context, &len);
|
|
|
|
if (!rc)
|
|
|
|
rc = len;
|
|
|
|
*_buffer = context;
|
|
|
|
return rc;
|
|
|
|
}
|
|
|
|
|
2006-06-22 21:47:17 +00:00
|
|
|
#endif
|
|
|
|
|
2005-04-16 22:20:36 +00:00
|
|
|
static struct security_operations selinux_ops = {
|
2008-03-06 16:09:10 +00:00
|
|
|
.name = "selinux",
|
|
|
|
|
2009-05-07 09:26:19 +00:00
|
|
|
.ptrace_access_check = selinux_ptrace_access_check,
|
security: Fix setting of PF_SUPERPRIV by __capable()
Fix the setting of PF_SUPERPRIV by __capable() as it could corrupt the flags
the target process if that is not the current process and it is trying to
change its own flags in a different way at the same time.
__capable() is using neither atomic ops nor locking to protect t->flags. This
patch removes __capable() and introduces has_capability() that doesn't set
PF_SUPERPRIV on the process being queried.
This patch further splits security_ptrace() in two:
(1) security_ptrace_may_access(). This passes judgement on whether one
process may access another only (PTRACE_MODE_ATTACH for ptrace() and
PTRACE_MODE_READ for /proc), and takes a pointer to the child process.
current is the parent.
(2) security_ptrace_traceme(). This passes judgement on PTRACE_TRACEME only,
and takes only a pointer to the parent process. current is the child.
In Smack and commoncap, this uses has_capability() to determine whether
the parent will be permitted to use PTRACE_ATTACH if normal checks fail.
This does not set PF_SUPERPRIV.
Two of the instances of __capable() actually only act on current, and so have
been changed to calls to capable().
Of the places that were using __capable():
(1) The OOM killer calls __capable() thrice when weighing the killability of a
process. All of these now use has_capability().
(2) cap_ptrace() and smack_ptrace() were using __capable() to check to see
whether the parent was allowed to trace any process. As mentioned above,
these have been split. For PTRACE_ATTACH and /proc, capable() is now
used, and for PTRACE_TRACEME, has_capability() is used.
(3) cap_safe_nice() only ever saw current, so now uses capable().
(4) smack_setprocattr() rejected accesses to tasks other than current just
after calling __capable(), so the order of these two tests have been
switched and capable() is used instead.
(5) In smack_file_send_sigiotask(), we need to allow privileged processes to
receive SIGIO on files they're manipulating.
(6) In smack_task_wait(), we let a process wait for a privileged process,
whether or not the process doing the waiting is privileged.
I've tested this with the LTP SELinux and syscalls testscripts.
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Acked-by: Casey Schaufler <casey@schaufler-ca.com>
Acked-by: Andrew G. Morgan <morgan@kernel.org>
Acked-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: James Morris <jmorris@namei.org>
2008-08-14 10:37:28 +00:00
|
|
|
.ptrace_traceme = selinux_ptrace_traceme,
|
2005-04-16 22:20:36 +00:00
|
|
|
.capget = selinux_capget,
|
CRED: Inaugurate COW credentials
Inaugurate copy-on-write credentials management. This uses RCU to manage the
credentials pointer in the task_struct with respect to accesses by other tasks.
A process may only modify its own credentials, and so does not need locking to
access or modify its own credentials.
A mutex (cred_replace_mutex) is added to the task_struct to control the effect
of PTRACE_ATTACHED on credential calculations, particularly with respect to
execve().
With this patch, the contents of an active credentials struct may not be
changed directly; rather a new set of credentials must be prepared, modified
and committed using something like the following sequence of events:
struct cred *new = prepare_creds();
int ret = blah(new);
if (ret < 0) {
abort_creds(new);
return ret;
}
return commit_creds(new);
There are some exceptions to this rule: the keyrings pointed to by the active
credentials may be instantiated - keyrings violate the COW rule as managing
COW keyrings is tricky, given that it is possible for a task to directly alter
the keys in a keyring in use by another task.
To help enforce this, various pointers to sets of credentials, such as those in
the task_struct, are declared const. The purpose of this is compile-time
discouragement of altering credentials through those pointers. Once a set of
credentials has been made public through one of these pointers, it may not be
modified, except under special circumstances:
(1) Its reference count may incremented and decremented.
(2) The keyrings to which it points may be modified, but not replaced.
The only safe way to modify anything else is to create a replacement and commit
using the functions described in Documentation/credentials.txt (which will be
added by a later patch).
This patch and the preceding patches have been tested with the LTP SELinux
testsuite.
This patch makes several logical sets of alteration:
(1) execve().
This now prepares and commits credentials in various places in the
security code rather than altering the current creds directly.
(2) Temporary credential overrides.
do_coredump() and sys_faccessat() now prepare their own credentials and
temporarily override the ones currently on the acting thread, whilst
preventing interference from other threads by holding cred_replace_mutex
on the thread being dumped.
This will be replaced in a future patch by something that hands down the
credentials directly to the functions being called, rather than altering
the task's objective credentials.
(3) LSM interface.
A number of functions have been changed, added or removed:
(*) security_capset_check(), ->capset_check()
(*) security_capset_set(), ->capset_set()
Removed in favour of security_capset().
(*) security_capset(), ->capset()
New. This is passed a pointer to the new creds, a pointer to the old
creds and the proposed capability sets. It should fill in the new
creds or return an error. All pointers, barring the pointer to the
new creds, are now const.
(*) security_bprm_apply_creds(), ->bprm_apply_creds()
Changed; now returns a value, which will cause the process to be
killed if it's an error.
(*) security_task_alloc(), ->task_alloc_security()
Removed in favour of security_prepare_creds().
(*) security_cred_free(), ->cred_free()
New. Free security data attached to cred->security.
(*) security_prepare_creds(), ->cred_prepare()
New. Duplicate any security data attached to cred->security.
(*) security_commit_creds(), ->cred_commit()
New. Apply any security effects for the upcoming installation of new
security by commit_creds().
(*) security_task_post_setuid(), ->task_post_setuid()
Removed in favour of security_task_fix_setuid().
(*) security_task_fix_setuid(), ->task_fix_setuid()
Fix up the proposed new credentials for setuid(). This is used by
cap_set_fix_setuid() to implicitly adjust capabilities in line with
setuid() changes. Changes are made to the new credentials, rather
than the task itself as in security_task_post_setuid().
(*) security_task_reparent_to_init(), ->task_reparent_to_init()
Removed. Instead the task being reparented to init is referred
directly to init's credentials.
NOTE! This results in the loss of some state: SELinux's osid no
longer records the sid of the thread that forked it.
(*) security_key_alloc(), ->key_alloc()
(*) security_key_permission(), ->key_permission()
Changed. These now take cred pointers rather than task pointers to
refer to the security context.
(4) sys_capset().
This has been simplified and uses less locking. The LSM functions it
calls have been merged.
(5) reparent_to_kthreadd().
This gives the current thread the same credentials as init by simply using
commit_thread() to point that way.
(6) __sigqueue_alloc() and switch_uid()
__sigqueue_alloc() can't stop the target task from changing its creds
beneath it, so this function gets a reference to the currently applicable
user_struct which it then passes into the sigqueue struct it returns if
successful.
switch_uid() is now called from commit_creds(), and possibly should be
folded into that. commit_creds() should take care of protecting
__sigqueue_alloc().
(7) [sg]et[ug]id() and co and [sg]et_current_groups.
The set functions now all use prepare_creds(), commit_creds() and
abort_creds() to build and check a new set of credentials before applying
it.
security_task_set[ug]id() is called inside the prepared section. This
guarantees that nothing else will affect the creds until we've finished.
The calling of set_dumpable() has been moved into commit_creds().
Much of the functionality of set_user() has been moved into
commit_creds().
The get functions all simply access the data directly.
(8) security_task_prctl() and cap_task_prctl().
security_task_prctl() has been modified to return -ENOSYS if it doesn't
want to handle a function, or otherwise return the return value directly
rather than through an argument.
Additionally, cap_task_prctl() now prepares a new set of credentials, even
if it doesn't end up using it.
(9) Keyrings.
A number of changes have been made to the keyrings code:
(a) switch_uid_keyring(), copy_keys(), exit_keys() and suid_keys() have
all been dropped and built in to the credentials functions directly.
They may want separating out again later.
(b) key_alloc() and search_process_keyrings() now take a cred pointer
rather than a task pointer to specify the security context.
(c) copy_creds() gives a new thread within the same thread group a new
thread keyring if its parent had one, otherwise it discards the thread
keyring.
(d) The authorisation key now points directly to the credentials to extend
the search into rather pointing to the task that carries them.
(e) Installing thread, process or session keyrings causes a new set of
credentials to be created, even though it's not strictly necessary for
process or session keyrings (they're shared).
(10) Usermode helper.
The usermode helper code now carries a cred struct pointer in its
subprocess_info struct instead of a new session keyring pointer. This set
of credentials is derived from init_cred and installed on the new process
after it has been cloned.
call_usermodehelper_setup() allocates the new credentials and
call_usermodehelper_freeinfo() discards them if they haven't been used. A
special cred function (prepare_usermodeinfo_creds()) is provided
specifically for call_usermodehelper_setup() to call.
call_usermodehelper_setkeys() adjusts the credentials to sport the
supplied keyring as the new session keyring.
(11) SELinux.
SELinux has a number of changes, in addition to those to support the LSM
interface changes mentioned above:
(a) selinux_setprocattr() no longer does its check for whether the
current ptracer can access processes with the new SID inside the lock
that covers getting the ptracer's SID. Whilst this lock ensures that
the check is done with the ptracer pinned, the result is only valid
until the lock is released, so there's no point doing it inside the
lock.
(12) is_single_threaded().
This function has been extracted from selinux_setprocattr() and put into
a file of its own in the lib/ directory as join_session_keyring() now
wants to use it too.
The code in SELinux just checked to see whether a task shared mm_structs
with other tasks (CLONE_VM), but that isn't good enough. We really want
to know if they're part of the same thread group (CLONE_THREAD).
(13) nfsd.
The NFS server daemon now has to use the COW credentials to set the
credentials it is going to use. It really needs to pass the credentials
down to the functions it calls, but it can't do that until other patches
in this series have been applied.
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: James Morris <jmorris@namei.org>
Signed-off-by: James Morris <jmorris@namei.org>
2008-11-13 23:39:23 +00:00
|
|
|
.capset = selinux_capset,
|
2005-04-16 22:20:36 +00:00
|
|
|
.capable = selinux_capable,
|
|
|
|
.quotactl = selinux_quotactl,
|
|
|
|
.quota_on = selinux_quota_on,
|
|
|
|
.syslog = selinux_syslog,
|
|
|
|
.vm_enough_memory = selinux_vm_enough_memory,
|
|
|
|
|
|
|
|
.netlink_send = selinux_netlink_send,
|
|
|
|
|
CRED: Make execve() take advantage of copy-on-write credentials
Make execve() take advantage of copy-on-write credentials, allowing it to set
up the credentials in advance, and then commit the whole lot after the point
of no return.
This patch and the preceding patches have been tested with the LTP SELinux
testsuite.
This patch makes several logical sets of alteration:
(1) execve().
The credential bits from struct linux_binprm are, for the most part,
replaced with a single credentials pointer (bprm->cred). This means that
all the creds can be calculated in advance and then applied at the point
of no return with no possibility of failure.
I would like to replace bprm->cap_effective with:
cap_isclear(bprm->cap_effective)
but this seems impossible due to special behaviour for processes of pid 1
(they always retain their parent's capability masks where normally they'd
be changed - see cap_bprm_set_creds()).
The following sequence of events now happens:
(a) At the start of do_execve, the current task's cred_exec_mutex is
locked to prevent PTRACE_ATTACH from obsoleting the calculation of
creds that we make.
(a) prepare_exec_creds() is then called to make a copy of the current
task's credentials and prepare it. This copy is then assigned to
bprm->cred.
This renders security_bprm_alloc() and security_bprm_free()
unnecessary, and so they've been removed.
(b) The determination of unsafe execution is now performed immediately
after (a) rather than later on in the code. The result is stored in
bprm->unsafe for future reference.
(c) prepare_binprm() is called, possibly multiple times.
(i) This applies the result of set[ug]id binaries to the new creds
attached to bprm->cred. Personality bit clearance is recorded,
but now deferred on the basis that the exec procedure may yet
fail.
(ii) This then calls the new security_bprm_set_creds(). This should
calculate the new LSM and capability credentials into *bprm->cred.
This folds together security_bprm_set() and parts of
security_bprm_apply_creds() (these two have been removed).
Anything that might fail must be done at this point.
(iii) bprm->cred_prepared is set to 1.
bprm->cred_prepared is 0 on the first pass of the security
calculations, and 1 on all subsequent passes. This allows SELinux
in (ii) to base its calculations only on the initial script and
not on the interpreter.
(d) flush_old_exec() is called to commit the task to execution. This
performs the following steps with regard to credentials:
(i) Clear pdeath_signal and set dumpable on certain circumstances that
may not be covered by commit_creds().
(ii) Clear any bits in current->personality that were deferred from
(c.i).
(e) install_exec_creds() [compute_creds() as was] is called to install the
new credentials. This performs the following steps with regard to
credentials:
(i) Calls security_bprm_committing_creds() to apply any security
requirements, such as flushing unauthorised files in SELinux, that
must be done before the credentials are changed.
This is made up of bits of security_bprm_apply_creds() and
security_bprm_post_apply_creds(), both of which have been removed.
This function is not allowed to fail; anything that might fail
must have been done in (c.ii).
(ii) Calls commit_creds() to apply the new credentials in a single
assignment (more or less). Possibly pdeath_signal and dumpable
should be part of struct creds.
(iii) Unlocks the task's cred_replace_mutex, thus allowing
PTRACE_ATTACH to take place.
(iv) Clears The bprm->cred pointer as the credentials it was holding
are now immutable.
(v) Calls security_bprm_committed_creds() to apply any security
alterations that must be done after the creds have been changed.
SELinux uses this to flush signals and signal handlers.
(f) If an error occurs before (d.i), bprm_free() will call abort_creds()
to destroy the proposed new credentials and will then unlock
cred_replace_mutex. No changes to the credentials will have been
made.
(2) LSM interface.
A number of functions have been changed, added or removed:
(*) security_bprm_alloc(), ->bprm_alloc_security()
(*) security_bprm_free(), ->bprm_free_security()
Removed in favour of preparing new credentials and modifying those.
(*) security_bprm_apply_creds(), ->bprm_apply_creds()
(*) security_bprm_post_apply_creds(), ->bprm_post_apply_creds()
Removed; split between security_bprm_set_creds(),
security_bprm_committing_creds() and security_bprm_committed_creds().
(*) security_bprm_set(), ->bprm_set_security()
Removed; folded into security_bprm_set_creds().
(*) security_bprm_set_creds(), ->bprm_set_creds()
New. The new credentials in bprm->creds should be checked and set up
as appropriate. bprm->cred_prepared is 0 on the first call, 1 on the
second and subsequent calls.
(*) security_bprm_committing_creds(), ->bprm_committing_creds()
(*) security_bprm_committed_creds(), ->bprm_committed_creds()
New. Apply the security effects of the new credentials. This
includes closing unauthorised files in SELinux. This function may not
fail. When the former is called, the creds haven't yet been applied
to the process; when the latter is called, they have.
The former may access bprm->cred, the latter may not.
(3) SELinux.
SELinux has a number of changes, in addition to those to support the LSM
interface changes mentioned above:
(a) The bprm_security_struct struct has been removed in favour of using
the credentials-under-construction approach.
(c) flush_unauthorized_files() now takes a cred pointer and passes it on
to inode_has_perm(), file_has_perm() and dentry_open().
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: James Morris <jmorris@namei.org>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Signed-off-by: James Morris <jmorris@namei.org>
2008-11-13 23:39:24 +00:00
|
|
|
.bprm_set_creds = selinux_bprm_set_creds,
|
|
|
|
.bprm_committing_creds = selinux_bprm_committing_creds,
|
|
|
|
.bprm_committed_creds = selinux_bprm_committed_creds,
|
2005-04-16 22:20:36 +00:00
|
|
|
.bprm_secureexec = selinux_bprm_secureexec,
|
|
|
|
|
|
|
|
.sb_alloc_security = selinux_sb_alloc_security,
|
|
|
|
.sb_free_security = selinux_sb_free_security,
|
|
|
|
.sb_copy_data = selinux_sb_copy_data,
|
2011-03-03 21:09:14 +00:00
|
|
|
.sb_remount = selinux_sb_remount,
|
2008-04-17 17:17:49 +00:00
|
|
|
.sb_kern_mount = selinux_sb_kern_mount,
|
2008-07-03 23:47:13 +00:00
|
|
|
.sb_show_options = selinux_sb_show_options,
|
2005-04-16 22:20:36 +00:00
|
|
|
.sb_statfs = selinux_sb_statfs,
|
|
|
|
.sb_mount = selinux_mount,
|
|
|
|
.sb_umount = selinux_umount,
|
2007-11-30 18:00:35 +00:00
|
|
|
.sb_set_mnt_opts = selinux_set_mnt_opts,
|
2008-04-17 17:17:49 +00:00
|
|
|
.sb_clone_mnt_opts = selinux_sb_clone_mnt_opts,
|
2008-03-05 15:31:54 +00:00
|
|
|
.sb_parse_opts_str = selinux_parse_opts_str,
|
|
|
|
|
2013-05-22 16:50:34 +00:00
|
|
|
.dentry_init_security = selinux_dentry_init_security,
|
2005-04-16 22:20:36 +00:00
|
|
|
|
|
|
|
.inode_alloc_security = selinux_inode_alloc_security,
|
|
|
|
.inode_free_security = selinux_inode_free_security,
|
2005-09-09 20:01:35 +00:00
|
|
|
.inode_init_security = selinux_inode_init_security,
|
2005-04-16 22:20:36 +00:00
|
|
|
.inode_create = selinux_inode_create,
|
|
|
|
.inode_link = selinux_inode_link,
|
|
|
|
.inode_unlink = selinux_inode_unlink,
|
|
|
|
.inode_symlink = selinux_inode_symlink,
|
|
|
|
.inode_mkdir = selinux_inode_mkdir,
|
|
|
|
.inode_rmdir = selinux_inode_rmdir,
|
|
|
|
.inode_mknod = selinux_inode_mknod,
|
|
|
|
.inode_rename = selinux_inode_rename,
|
|
|
|
.inode_readlink = selinux_inode_readlink,
|
|
|
|
.inode_follow_link = selinux_inode_follow_link,
|
|
|
|
.inode_permission = selinux_inode_permission,
|
|
|
|
.inode_setattr = selinux_inode_setattr,
|
|
|
|
.inode_getattr = selinux_inode_getattr,
|
|
|
|
.inode_setxattr = selinux_inode_setxattr,
|
|
|
|
.inode_post_setxattr = selinux_inode_post_setxattr,
|
|
|
|
.inode_getxattr = selinux_inode_getxattr,
|
|
|
|
.inode_listxattr = selinux_inode_listxattr,
|
|
|
|
.inode_removexattr = selinux_inode_removexattr,
|
2008-04-17 17:17:49 +00:00
|
|
|
.inode_getsecurity = selinux_inode_getsecurity,
|
|
|
|
.inode_setsecurity = selinux_inode_setsecurity,
|
|
|
|
.inode_listsecurity = selinux_inode_listsecurity,
|
2008-05-14 15:27:45 +00:00
|
|
|
.inode_getsecid = selinux_inode_getsecid,
|
2005-04-16 22:20:36 +00:00
|
|
|
|
|
|
|
.file_permission = selinux_file_permission,
|
|
|
|
.file_alloc_security = selinux_file_alloc_security,
|
|
|
|
.file_free_security = selinux_file_free_security,
|
|
|
|
.file_ioctl = selinux_file_ioctl,
|
2012-05-30 17:30:51 +00:00
|
|
|
.mmap_file = selinux_mmap_file,
|
|
|
|
.mmap_addr = selinux_mmap_addr,
|
2005-04-16 22:20:36 +00:00
|
|
|
.file_mprotect = selinux_file_mprotect,
|
|
|
|
.file_lock = selinux_file_lock,
|
|
|
|
.file_fcntl = selinux_file_fcntl,
|
|
|
|
.file_set_fowner = selinux_file_set_fowner,
|
|
|
|
.file_send_sigiotask = selinux_file_send_sigiotask,
|
|
|
|
.file_receive = selinux_file_receive,
|
|
|
|
|
2012-04-04 17:45:40 +00:00
|
|
|
.file_open = selinux_file_open,
|
2007-09-14 00:27:07 +00:00
|
|
|
|
2005-04-16 22:20:36 +00:00
|
|
|
.task_create = selinux_task_create,
|
KEYS: Add a keyctl to install a process's session keyring on its parent [try #6]
Add a keyctl to install a process's session keyring onto its parent. This
replaces the parent's session keyring. Because the COW credential code does
not permit one process to change another process's credentials directly, the
change is deferred until userspace next starts executing again. Normally this
will be after a wait*() syscall.
To support this, three new security hooks have been provided:
cred_alloc_blank() to allocate unset security creds, cred_transfer() to fill in
the blank security creds and key_session_to_parent() - which asks the LSM if
the process may replace its parent's session keyring.
The replacement may only happen if the process has the same ownership details
as its parent, and the process has LINK permission on the session keyring, and
the session keyring is owned by the process, and the LSM permits it.
Note that this requires alteration to each architecture's notify_resume path.
This has been done for all arches barring blackfin, m68k* and xtensa, all of
which need assembly alteration to support TIF_NOTIFY_RESUME. This allows the
replacement to be performed at the point the parent process resumes userspace
execution.
This allows the userspace AFS pioctl emulation to fully emulate newpag() and
the VIOCSETTOK and VIOCSETTOK2 pioctls, all of which require the ability to
alter the parent process's PAG membership. However, since kAFS doesn't use
PAGs per se, but rather dumps the keys into the session keyring, the session
keyring of the parent must be replaced if, for example, VIOCSETTOK is passed
the newpag flag.
This can be tested with the following program:
#include <stdio.h>
#include <stdlib.h>
#include <keyutils.h>
#define KEYCTL_SESSION_TO_PARENT 18
#define OSERROR(X, S) do { if ((long)(X) == -1) { perror(S); exit(1); } } while(0)
int main(int argc, char **argv)
{
key_serial_t keyring, key;
long ret;
keyring = keyctl_join_session_keyring(argv[1]);
OSERROR(keyring, "keyctl_join_session_keyring");
key = add_key("user", "a", "b", 1, keyring);
OSERROR(key, "add_key");
ret = keyctl(KEYCTL_SESSION_TO_PARENT);
OSERROR(ret, "KEYCTL_SESSION_TO_PARENT");
return 0;
}
Compiled and linked with -lkeyutils, you should see something like:
[dhowells@andromeda ~]$ keyctl show
Session Keyring
-3 --alswrv 4043 4043 keyring: _ses
355907932 --alswrv 4043 -1 \_ keyring: _uid.4043
[dhowells@andromeda ~]$ /tmp/newpag
[dhowells@andromeda ~]$ keyctl show
Session Keyring
-3 --alswrv 4043 4043 keyring: _ses
1055658746 --alswrv 4043 4043 \_ user: a
[dhowells@andromeda ~]$ /tmp/newpag hello
[dhowells@andromeda ~]$ keyctl show
Session Keyring
-3 --alswrv 4043 4043 keyring: hello
340417692 --alswrv 4043 4043 \_ user: a
Where the test program creates a new session keyring, sticks a user key named
'a' into it and then installs it on its parent.
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: James Morris <jmorris@namei.org>
2009-09-02 08:14:21 +00:00
|
|
|
.cred_alloc_blank = selinux_cred_alloc_blank,
|
2008-11-13 23:39:17 +00:00
|
|
|
.cred_free = selinux_cred_free,
|
CRED: Inaugurate COW credentials
Inaugurate copy-on-write credentials management. This uses RCU to manage the
credentials pointer in the task_struct with respect to accesses by other tasks.
A process may only modify its own credentials, and so does not need locking to
access or modify its own credentials.
A mutex (cred_replace_mutex) is added to the task_struct to control the effect
of PTRACE_ATTACHED on credential calculations, particularly with respect to
execve().
With this patch, the contents of an active credentials struct may not be
changed directly; rather a new set of credentials must be prepared, modified
and committed using something like the following sequence of events:
struct cred *new = prepare_creds();
int ret = blah(new);
if (ret < 0) {
abort_creds(new);
return ret;
}
return commit_creds(new);
There are some exceptions to this rule: the keyrings pointed to by the active
credentials may be instantiated - keyrings violate the COW rule as managing
COW keyrings is tricky, given that it is possible for a task to directly alter
the keys in a keyring in use by another task.
To help enforce this, various pointers to sets of credentials, such as those in
the task_struct, are declared const. The purpose of this is compile-time
discouragement of altering credentials through those pointers. Once a set of
credentials has been made public through one of these pointers, it may not be
modified, except under special circumstances:
(1) Its reference count may incremented and decremented.
(2) The keyrings to which it points may be modified, but not replaced.
The only safe way to modify anything else is to create a replacement and commit
using the functions described in Documentation/credentials.txt (which will be
added by a later patch).
This patch and the preceding patches have been tested with the LTP SELinux
testsuite.
This patch makes several logical sets of alteration:
(1) execve().
This now prepares and commits credentials in various places in the
security code rather than altering the current creds directly.
(2) Temporary credential overrides.
do_coredump() and sys_faccessat() now prepare their own credentials and
temporarily override the ones currently on the acting thread, whilst
preventing interference from other threads by holding cred_replace_mutex
on the thread being dumped.
This will be replaced in a future patch by something that hands down the
credentials directly to the functions being called, rather than altering
the task's objective credentials.
(3) LSM interface.
A number of functions have been changed, added or removed:
(*) security_capset_check(), ->capset_check()
(*) security_capset_set(), ->capset_set()
Removed in favour of security_capset().
(*) security_capset(), ->capset()
New. This is passed a pointer to the new creds, a pointer to the old
creds and the proposed capability sets. It should fill in the new
creds or return an error. All pointers, barring the pointer to the
new creds, are now const.
(*) security_bprm_apply_creds(), ->bprm_apply_creds()
Changed; now returns a value, which will cause the process to be
killed if it's an error.
(*) security_task_alloc(), ->task_alloc_security()
Removed in favour of security_prepare_creds().
(*) security_cred_free(), ->cred_free()
New. Free security data attached to cred->security.
(*) security_prepare_creds(), ->cred_prepare()
New. Duplicate any security data attached to cred->security.
(*) security_commit_creds(), ->cred_commit()
New. Apply any security effects for the upcoming installation of new
security by commit_creds().
(*) security_task_post_setuid(), ->task_post_setuid()
Removed in favour of security_task_fix_setuid().
(*) security_task_fix_setuid(), ->task_fix_setuid()
Fix up the proposed new credentials for setuid(). This is used by
cap_set_fix_setuid() to implicitly adjust capabilities in line with
setuid() changes. Changes are made to the new credentials, rather
than the task itself as in security_task_post_setuid().
(*) security_task_reparent_to_init(), ->task_reparent_to_init()
Removed. Instead the task being reparented to init is referred
directly to init's credentials.
NOTE! This results in the loss of some state: SELinux's osid no
longer records the sid of the thread that forked it.
(*) security_key_alloc(), ->key_alloc()
(*) security_key_permission(), ->key_permission()
Changed. These now take cred pointers rather than task pointers to
refer to the security context.
(4) sys_capset().
This has been simplified and uses less locking. The LSM functions it
calls have been merged.
(5) reparent_to_kthreadd().
This gives the current thread the same credentials as init by simply using
commit_thread() to point that way.
(6) __sigqueue_alloc() and switch_uid()
__sigqueue_alloc() can't stop the target task from changing its creds
beneath it, so this function gets a reference to the currently applicable
user_struct which it then passes into the sigqueue struct it returns if
successful.
switch_uid() is now called from commit_creds(), and possibly should be
folded into that. commit_creds() should take care of protecting
__sigqueue_alloc().
(7) [sg]et[ug]id() and co and [sg]et_current_groups.
The set functions now all use prepare_creds(), commit_creds() and
abort_creds() to build and check a new set of credentials before applying
it.
security_task_set[ug]id() is called inside the prepared section. This
guarantees that nothing else will affect the creds until we've finished.
The calling of set_dumpable() has been moved into commit_creds().
Much of the functionality of set_user() has been moved into
commit_creds().
The get functions all simply access the data directly.
(8) security_task_prctl() and cap_task_prctl().
security_task_prctl() has been modified to return -ENOSYS if it doesn't
want to handle a function, or otherwise return the return value directly
rather than through an argument.
Additionally, cap_task_prctl() now prepares a new set of credentials, even
if it doesn't end up using it.
(9) Keyrings.
A number of changes have been made to the keyrings code:
(a) switch_uid_keyring(), copy_keys(), exit_keys() and suid_keys() have
all been dropped and built in to the credentials functions directly.
They may want separating out again later.
(b) key_alloc() and search_process_keyrings() now take a cred pointer
rather than a task pointer to specify the security context.
(c) copy_creds() gives a new thread within the same thread group a new
thread keyring if its parent had one, otherwise it discards the thread
keyring.
(d) The authorisation key now points directly to the credentials to extend
the search into rather pointing to the task that carries them.
(e) Installing thread, process or session keyrings causes a new set of
credentials to be created, even though it's not strictly necessary for
process or session keyrings (they're shared).
(10) Usermode helper.
The usermode helper code now carries a cred struct pointer in its
subprocess_info struct instead of a new session keyring pointer. This set
of credentials is derived from init_cred and installed on the new process
after it has been cloned.
call_usermodehelper_setup() allocates the new credentials and
call_usermodehelper_freeinfo() discards them if they haven't been used. A
special cred function (prepare_usermodeinfo_creds()) is provided
specifically for call_usermodehelper_setup() to call.
call_usermodehelper_setkeys() adjusts the credentials to sport the
supplied keyring as the new session keyring.
(11) SELinux.
SELinux has a number of changes, in addition to those to support the LSM
interface changes mentioned above:
(a) selinux_setprocattr() no longer does its check for whether the
current ptracer can access processes with the new SID inside the lock
that covers getting the ptracer's SID. Whilst this lock ensures that
the check is done with the ptracer pinned, the result is only valid
until the lock is released, so there's no point doing it inside the
lock.
(12) is_single_threaded().
This function has been extracted from selinux_setprocattr() and put into
a file of its own in the lib/ directory as join_session_keyring() now
wants to use it too.
The code in SELinux just checked to see whether a task shared mm_structs
with other tasks (CLONE_VM), but that isn't good enough. We really want
to know if they're part of the same thread group (CLONE_THREAD).
(13) nfsd.
The NFS server daemon now has to use the COW credentials to set the
credentials it is going to use. It really needs to pass the credentials
down to the functions it calls, but it can't do that until other patches
in this series have been applied.
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: James Morris <jmorris@namei.org>
Signed-off-by: James Morris <jmorris@namei.org>
2008-11-13 23:39:23 +00:00
|
|
|
.cred_prepare = selinux_cred_prepare,
|
KEYS: Add a keyctl to install a process's session keyring on its parent [try #6]
Add a keyctl to install a process's session keyring onto its parent. This
replaces the parent's session keyring. Because the COW credential code does
not permit one process to change another process's credentials directly, the
change is deferred until userspace next starts executing again. Normally this
will be after a wait*() syscall.
To support this, three new security hooks have been provided:
cred_alloc_blank() to allocate unset security creds, cred_transfer() to fill in
the blank security creds and key_session_to_parent() - which asks the LSM if
the process may replace its parent's session keyring.
The replacement may only happen if the process has the same ownership details
as its parent, and the process has LINK permission on the session keyring, and
the session keyring is owned by the process, and the LSM permits it.
Note that this requires alteration to each architecture's notify_resume path.
This has been done for all arches barring blackfin, m68k* and xtensa, all of
which need assembly alteration to support TIF_NOTIFY_RESUME. This allows the
replacement to be performed at the point the parent process resumes userspace
execution.
This allows the userspace AFS pioctl emulation to fully emulate newpag() and
the VIOCSETTOK and VIOCSETTOK2 pioctls, all of which require the ability to
alter the parent process's PAG membership. However, since kAFS doesn't use
PAGs per se, but rather dumps the keys into the session keyring, the session
keyring of the parent must be replaced if, for example, VIOCSETTOK is passed
the newpag flag.
This can be tested with the following program:
#include <stdio.h>
#include <stdlib.h>
#include <keyutils.h>
#define KEYCTL_SESSION_TO_PARENT 18
#define OSERROR(X, S) do { if ((long)(X) == -1) { perror(S); exit(1); } } while(0)
int main(int argc, char **argv)
{
key_serial_t keyring, key;
long ret;
keyring = keyctl_join_session_keyring(argv[1]);
OSERROR(keyring, "keyctl_join_session_keyring");
key = add_key("user", "a", "b", 1, keyring);
OSERROR(key, "add_key");
ret = keyctl(KEYCTL_SESSION_TO_PARENT);
OSERROR(ret, "KEYCTL_SESSION_TO_PARENT");
return 0;
}
Compiled and linked with -lkeyutils, you should see something like:
[dhowells@andromeda ~]$ keyctl show
Session Keyring
-3 --alswrv 4043 4043 keyring: _ses
355907932 --alswrv 4043 -1 \_ keyring: _uid.4043
[dhowells@andromeda ~]$ /tmp/newpag
[dhowells@andromeda ~]$ keyctl show
Session Keyring
-3 --alswrv 4043 4043 keyring: _ses
1055658746 --alswrv 4043 4043 \_ user: a
[dhowells@andromeda ~]$ /tmp/newpag hello
[dhowells@andromeda ~]$ keyctl show
Session Keyring
-3 --alswrv 4043 4043 keyring: hello
340417692 --alswrv 4043 4043 \_ user: a
Where the test program creates a new session keyring, sticks a user key named
'a' into it and then installs it on its parent.
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: James Morris <jmorris@namei.org>
2009-09-02 08:14:21 +00:00
|
|
|
.cred_transfer = selinux_cred_transfer,
|
2008-11-13 23:39:28 +00:00
|
|
|
.kernel_act_as = selinux_kernel_act_as,
|
|
|
|
.kernel_create_files_as = selinux_kernel_create_files_as,
|
2009-08-13 13:45:03 +00:00
|
|
|
.kernel_module_request = selinux_kernel_module_request,
|
2005-04-16 22:20:36 +00:00
|
|
|
.task_setpgid = selinux_task_setpgid,
|
|
|
|
.task_getpgid = selinux_task_getpgid,
|
2008-04-17 17:17:49 +00:00
|
|
|
.task_getsid = selinux_task_getsid,
|
2006-06-30 08:55:46 +00:00
|
|
|
.task_getsecid = selinux_task_getsecid,
|
2005-04-16 22:20:36 +00:00
|
|
|
.task_setnice = selinux_task_setnice,
|
2006-06-23 09:03:58 +00:00
|
|
|
.task_setioprio = selinux_task_setioprio,
|
2006-06-30 08:55:49 +00:00
|
|
|
.task_getioprio = selinux_task_getioprio,
|
2005-04-16 22:20:36 +00:00
|
|
|
.task_setrlimit = selinux_task_setrlimit,
|
|
|
|
.task_setscheduler = selinux_task_setscheduler,
|
|
|
|
.task_getscheduler = selinux_task_getscheduler,
|
2006-06-23 09:04:01 +00:00
|
|
|
.task_movememory = selinux_task_movememory,
|
2005-04-16 22:20:36 +00:00
|
|
|
.task_kill = selinux_task_kill,
|
|
|
|
.task_wait = selinux_task_wait,
|
2008-04-17 17:17:49 +00:00
|
|
|
.task_to_inode = selinux_task_to_inode,
|
2005-04-16 22:20:36 +00:00
|
|
|
|
|
|
|
.ipc_permission = selinux_ipc_permission,
|
2008-05-14 15:27:45 +00:00
|
|
|
.ipc_getsecid = selinux_ipc_getsecid,
|
2005-04-16 22:20:36 +00:00
|
|
|
|
|
|
|
.msg_msg_alloc_security = selinux_msg_msg_alloc_security,
|
|
|
|
.msg_msg_free_security = selinux_msg_msg_free_security,
|
|
|
|
|
|
|
|
.msg_queue_alloc_security = selinux_msg_queue_alloc_security,
|
|
|
|
.msg_queue_free_security = selinux_msg_queue_free_security,
|
|
|
|
.msg_queue_associate = selinux_msg_queue_associate,
|
|
|
|
.msg_queue_msgctl = selinux_msg_queue_msgctl,
|
|
|
|
.msg_queue_msgsnd = selinux_msg_queue_msgsnd,
|
|
|
|
.msg_queue_msgrcv = selinux_msg_queue_msgrcv,
|
|
|
|
|
|
|
|
.shm_alloc_security = selinux_shm_alloc_security,
|
|
|
|
.shm_free_security = selinux_shm_free_security,
|
|
|
|
.shm_associate = selinux_shm_associate,
|
|
|
|
.shm_shmctl = selinux_shm_shmctl,
|
|
|
|
.shm_shmat = selinux_shm_shmat,
|
|
|
|
|
2008-04-17 17:17:49 +00:00
|
|
|
.sem_alloc_security = selinux_sem_alloc_security,
|
|
|
|
.sem_free_security = selinux_sem_free_security,
|
2005-04-16 22:20:36 +00:00
|
|
|
.sem_associate = selinux_sem_associate,
|
|
|
|
.sem_semctl = selinux_sem_semctl,
|
|
|
|
.sem_semop = selinux_sem_semop,
|
|
|
|
|
2008-04-17 17:17:49 +00:00
|
|
|
.d_instantiate = selinux_d_instantiate,
|
2005-04-16 22:20:36 +00:00
|
|
|
|
2008-04-17 17:17:49 +00:00
|
|
|
.getprocattr = selinux_getprocattr,
|
|
|
|
.setprocattr = selinux_setprocattr,
|
2005-04-16 22:20:36 +00:00
|
|
|
|
2013-05-22 16:50:35 +00:00
|
|
|
.ismaclabel = selinux_ismaclabel,
|
2006-08-02 21:12:06 +00:00
|
|
|
.secid_to_secctx = selinux_secid_to_secctx,
|
2008-01-15 23:47:35 +00:00
|
|
|
.secctx_to_secid = selinux_secctx_to_secid,
|
2006-08-02 21:12:06 +00:00
|
|
|
.release_secctx = selinux_release_secctx,
|
2009-09-03 18:25:57 +00:00
|
|
|
.inode_notifysecctx = selinux_inode_notifysecctx,
|
|
|
|
.inode_setsecctx = selinux_inode_setsecctx,
|
|
|
|
.inode_getsecctx = selinux_inode_getsecctx,
|
2006-08-02 21:12:06 +00:00
|
|
|
|
2008-04-17 17:17:49 +00:00
|
|
|
.unix_stream_connect = selinux_socket_unix_stream_connect,
|
2005-04-16 22:20:36 +00:00
|
|
|
.unix_may_send = selinux_socket_unix_may_send,
|
|
|
|
|
|
|
|
.socket_create = selinux_socket_create,
|
|
|
|
.socket_post_create = selinux_socket_post_create,
|
|
|
|
.socket_bind = selinux_socket_bind,
|
|
|
|
.socket_connect = selinux_socket_connect,
|
|
|
|
.socket_listen = selinux_socket_listen,
|
|
|
|
.socket_accept = selinux_socket_accept,
|
|
|
|
.socket_sendmsg = selinux_socket_sendmsg,
|
|
|
|
.socket_recvmsg = selinux_socket_recvmsg,
|
|
|
|
.socket_getsockname = selinux_socket_getsockname,
|
|
|
|
.socket_getpeername = selinux_socket_getpeername,
|
|
|
|
.socket_getsockopt = selinux_socket_getsockopt,
|
|
|
|
.socket_setsockopt = selinux_socket_setsockopt,
|
|
|
|
.socket_shutdown = selinux_socket_shutdown,
|
|
|
|
.socket_sock_rcv_skb = selinux_socket_sock_rcv_skb,
|
[SECURITY]: TCP/UDP getpeersec
This patch implements an application of the LSM-IPSec networking
controls whereby an application can determine the label of the
security association its TCP or UDP sockets are currently connected to
via getsockopt and the auxiliary data mechanism of recvmsg.
Patch purpose:
This patch enables a security-aware application to retrieve the
security context of an IPSec security association a particular TCP or
UDP socket is using. The application can then use this security
context to determine the security context for processing on behalf of
the peer at the other end of this connection. In the case of UDP, the
security context is for each individual packet. An example
application is the inetd daemon, which could be modified to start
daemons running at security contexts dependent on the remote client.
Patch design approach:
- Design for TCP
The patch enables the SELinux LSM to set the peer security context for
a socket based on the security context of the IPSec security
association. The application may retrieve this context using
getsockopt. When called, the kernel determines if the socket is a
connected (TCP_ESTABLISHED) TCP socket and, if so, uses the dst_entry
cache on the socket to retrieve the security associations. If a
security association has a security context, the context string is
returned, as for UNIX domain sockets.
- Design for UDP
Unlike TCP, UDP is connectionless. This requires a somewhat different
API to retrieve the peer security context. With TCP, the peer
security context stays the same throughout the connection, thus it can
be retrieved at any time between when the connection is established
and when it is torn down. With UDP, each read/write can have
different peer and thus the security context might change every time.
As a result the security context retrieval must be done TOGETHER with
the packet retrieval.
The solution is to build upon the existing Unix domain socket API for
retrieving user credentials. Linux offers the API for obtaining user
credentials via ancillary messages (i.e., out of band/control messages
that are bundled together with a normal message).
Patch implementation details:
- Implementation for TCP
The security context can be retrieved by applications using getsockopt
with the existing SO_PEERSEC flag. As an example (ignoring error
checking):
getsockopt(sockfd, SOL_SOCKET, SO_PEERSEC, optbuf, &optlen);
printf("Socket peer context is: %s\n", optbuf);
The SELinux function, selinux_socket_getpeersec, is extended to check
for labeled security associations for connected (TCP_ESTABLISHED ==
sk->sk_state) TCP sockets only. If so, the socket has a dst_cache of
struct dst_entry values that may refer to security associations. If
these have security associations with security contexts, the security
context is returned.
getsockopt returns a buffer that contains a security context string or
the buffer is unmodified.
- Implementation for UDP
To retrieve the security context, the application first indicates to
the kernel such desire by setting the IP_PASSSEC option via
getsockopt. Then the application retrieves the security context using
the auxiliary data mechanism.
An example server application for UDP should look like this:
toggle = 1;
toggle_len = sizeof(toggle);
setsockopt(sockfd, SOL_IP, IP_PASSSEC, &toggle, &toggle_len);
recvmsg(sockfd, &msg_hdr, 0);
if (msg_hdr.msg_controllen > sizeof(struct cmsghdr)) {
cmsg_hdr = CMSG_FIRSTHDR(&msg_hdr);
if (cmsg_hdr->cmsg_len <= CMSG_LEN(sizeof(scontext)) &&
cmsg_hdr->cmsg_level == SOL_IP &&
cmsg_hdr->cmsg_type == SCM_SECURITY) {
memcpy(&scontext, CMSG_DATA(cmsg_hdr), sizeof(scontext));
}
}
ip_setsockopt is enhanced with a new socket option IP_PASSSEC to allow
a server socket to receive security context of the peer. A new
ancillary message type SCM_SECURITY.
When the packet is received we get the security context from the
sec_path pointer which is contained in the sk_buff, and copy it to the
ancillary message space. An additional LSM hook,
selinux_socket_getpeersec_udp, is defined to retrieve the security
context from the SELinux space. The existing function,
selinux_socket_getpeersec does not suit our purpose, because the
security context is copied directly to user space, rather than to
kernel space.
Testing:
We have tested the patch by setting up TCP and UDP connections between
applications on two machines using the IPSec policies that result in
labeled security associations being built. For TCP, we can then
extract the peer security context using getsockopt on either end. For
UDP, the receiving end can retrieve the security context using the
auxiliary data mechanism of recvmsg.
Signed-off-by: Catherine Zhang <cxzhang@watson.ibm.com>
Acked-by: James Morris <jmorris@namei.org>
Acked-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-03-21 06:41:23 +00:00
|
|
|
.socket_getpeersec_stream = selinux_socket_getpeersec_stream,
|
|
|
|
.socket_getpeersec_dgram = selinux_socket_getpeersec_dgram,
|
2005-04-16 22:20:36 +00:00
|
|
|
.sk_alloc_security = selinux_sk_alloc_security,
|
|
|
|
.sk_free_security = selinux_sk_free_security,
|
2006-08-05 06:08:56 +00:00
|
|
|
.sk_clone_security = selinux_sk_clone_security,
|
2008-04-17 17:17:49 +00:00
|
|
|
.sk_getsecid = selinux_sk_getsecid,
|
2006-07-25 06:32:50 +00:00
|
|
|
.sock_graft = selinux_sock_graft,
|
|
|
|
.inet_conn_request = selinux_inet_conn_request,
|
|
|
|
.inet_csk_clone = selinux_inet_csk_clone,
|
2006-11-08 23:04:09 +00:00
|
|
|
.inet_conn_established = selinux_inet_conn_established,
|
2010-10-13 20:24:41 +00:00
|
|
|
.secmark_relabel_packet = selinux_secmark_relabel_packet,
|
|
|
|
.secmark_refcount_inc = selinux_secmark_refcount_inc,
|
|
|
|
.secmark_refcount_dec = selinux_secmark_refcount_dec,
|
2006-07-25 06:32:50 +00:00
|
|
|
.req_classify_flow = selinux_req_classify_flow,
|
2013-01-14 07:12:19 +00:00
|
|
|
.tun_dev_alloc_security = selinux_tun_dev_alloc_security,
|
|
|
|
.tun_dev_free_security = selinux_tun_dev_free_security,
|
2009-08-28 22:12:49 +00:00
|
|
|
.tun_dev_create = selinux_tun_dev_create,
|
2013-01-14 07:12:19 +00:00
|
|
|
.tun_dev_attach_queue = selinux_tun_dev_attach_queue,
|
2009-08-28 22:12:49 +00:00
|
|
|
.tun_dev_attach = selinux_tun_dev_attach,
|
2013-01-14 07:12:19 +00:00
|
|
|
.tun_dev_open = selinux_tun_dev_open,
|
2013-04-08 17:58:11 +00:00
|
|
|
.skb_owned_by = selinux_skb_owned_by,
|
[LSM-IPSec]: Per-packet access control.
This patch series implements per packet access control via the
extension of the Linux Security Modules (LSM) interface by hooks in
the XFRM and pfkey subsystems that leverage IPSec security
associations to label packets. Extensions to the SELinux LSM are
included that leverage the patch for this purpose.
This patch implements the changes necessary to the SELinux LSM to
create, deallocate, and use security contexts for policies
(xfrm_policy) and security associations (xfrm_state) that enable
control of a socket's ability to send and receive packets.
Patch purpose:
The patch is designed to enable the SELinux LSM to implement access
control on individual packets based on the strongly authenticated
IPSec security association. Such access controls augment the existing
ones in SELinux based on network interface and IP address. The former
are very coarse-grained, and the latter can be spoofed. By using
IPSec, the SELinux can control access to remote hosts based on
cryptographic keys generated using the IPSec mechanism. This enables
access control on a per-machine basis or per-application if the remote
machine is running the same mechanism and trusted to enforce the
access control policy.
Patch design approach:
The patch's main function is to authorize a socket's access to a IPSec
policy based on their security contexts. Since the communication is
implemented by a security association, the patch ensures that the
security association's negotiated and used have the same security
context. The patch enables allocation and deallocation of such
security contexts for policies and security associations. It also
enables copying of the security context when policies are cloned.
Lastly, the patch ensures that packets that are sent without using a
IPSec security assocation with a security context are allowed to be
sent in that manner.
A presentation available at
www.selinux-symposium.org/2005/presentations/session2/2-3-jaeger.pdf
from the SELinux symposium describes the overall approach.
Patch implementation details:
The function which authorizes a socket to perform a requested
operation (send/receive) on a IPSec policy (xfrm_policy) is
selinux_xfrm_policy_lookup. The Netfilter and rcv_skb hooks ensure
that if a IPSec SA with a securit y association has not been used,
then the socket is allowed to send or receive the packet,
respectively.
The patch implements SELinux function for allocating security contexts
when policies (xfrm_policy) are created via the pfkey or xfrm_user
interfaces via selinux_xfrm_policy_alloc. When a security association
is built, SELinux allocates the security context designated by the
XFRM subsystem which is based on that of the authorized policy via
selinux_xfrm_state_alloc.
When a xfrm_policy is cloned, the security context of that policy, if
any, is copied to the clone via selinux_xfrm_policy_clone.
When a xfrm_policy or xfrm_state is freed, its security context, if
any is also freed at selinux_xfrm_policy_free or
selinux_xfrm_state_free.
Testing:
The SELinux authorization function is tested using ipsec-tools. We
created policies and security associations with particular security
contexts and added SELinux access control policy entries to verify the
authorization decision. We also made sure that packets for which no
security context was supplied (which either did or did not use
security associations) were authorized using an unlabelled context.
Signed-off-by: Trent Jaeger <tjaeger@cse.psu.edu>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
2005-12-14 07:12:40 +00:00
|
|
|
|
|
|
|
#ifdef CONFIG_SECURITY_NETWORK_XFRM
|
|
|
|
.xfrm_policy_alloc_security = selinux_xfrm_policy_alloc,
|
|
|
|
.xfrm_policy_clone_security = selinux_xfrm_policy_clone,
|
|
|
|
.xfrm_policy_free_security = selinux_xfrm_policy_free,
|
2006-06-09 06:39:49 +00:00
|
|
|
.xfrm_policy_delete_security = selinux_xfrm_policy_delete,
|
2013-07-23 21:38:38 +00:00
|
|
|
.xfrm_state_alloc = selinux_xfrm_state_alloc,
|
|
|
|
.xfrm_state_alloc_acquire = selinux_xfrm_state_alloc_acquire,
|
[LSM-IPSec]: Per-packet access control.
This patch series implements per packet access control via the
extension of the Linux Security Modules (LSM) interface by hooks in
the XFRM and pfkey subsystems that leverage IPSec security
associations to label packets. Extensions to the SELinux LSM are
included that leverage the patch for this purpose.
This patch implements the changes necessary to the SELinux LSM to
create, deallocate, and use security contexts for policies
(xfrm_policy) and security associations (xfrm_state) that enable
control of a socket's ability to send and receive packets.
Patch purpose:
The patch is designed to enable the SELinux LSM to implement access
control on individual packets based on the strongly authenticated
IPSec security association. Such access controls augment the existing
ones in SELinux based on network interface and IP address. The former
are very coarse-grained, and the latter can be spoofed. By using
IPSec, the SELinux can control access to remote hosts based on
cryptographic keys generated using the IPSec mechanism. This enables
access control on a per-machine basis or per-application if the remote
machine is running the same mechanism and trusted to enforce the
access control policy.
Patch design approach:
The patch's main function is to authorize a socket's access to a IPSec
policy based on their security contexts. Since the communication is
implemented by a security association, the patch ensures that the
security association's negotiated and used have the same security
context. The patch enables allocation and deallocation of such
security contexts for policies and security associations. It also
enables copying of the security context when policies are cloned.
Lastly, the patch ensures that packets that are sent without using a
IPSec security assocation with a security context are allowed to be
sent in that manner.
A presentation available at
www.selinux-symposium.org/2005/presentations/session2/2-3-jaeger.pdf
from the SELinux symposium describes the overall approach.
Patch implementation details:
The function which authorizes a socket to perform a requested
operation (send/receive) on a IPSec policy (xfrm_policy) is
selinux_xfrm_policy_lookup. The Netfilter and rcv_skb hooks ensure
that if a IPSec SA with a securit y association has not been used,
then the socket is allowed to send or receive the packet,
respectively.
The patch implements SELinux function for allocating security contexts
when policies (xfrm_policy) are created via the pfkey or xfrm_user
interfaces via selinux_xfrm_policy_alloc. When a security association
is built, SELinux allocates the security context designated by the
XFRM subsystem which is based on that of the authorized policy via
selinux_xfrm_state_alloc.
When a xfrm_policy is cloned, the security context of that policy, if
any, is copied to the clone via selinux_xfrm_policy_clone.
When a xfrm_policy or xfrm_state is freed, its security context, if
any is also freed at selinux_xfrm_policy_free or
selinux_xfrm_state_free.
Testing:
The SELinux authorization function is tested using ipsec-tools. We
created policies and security associations with particular security
contexts and added SELinux access control policy entries to verify the
authorization decision. We also made sure that packets for which no
security context was supplied (which either did or did not use
security associations) were authorized using an unlabelled context.
Signed-off-by: Trent Jaeger <tjaeger@cse.psu.edu>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
2005-12-14 07:12:40 +00:00
|
|
|
.xfrm_state_free_security = selinux_xfrm_state_free,
|
2006-06-09 06:39:49 +00:00
|
|
|
.xfrm_state_delete_security = selinux_xfrm_state_delete,
|
2008-04-17 17:17:49 +00:00
|
|
|
.xfrm_policy_lookup = selinux_xfrm_policy_lookup,
|
2006-07-25 06:29:07 +00:00
|
|
|
.xfrm_state_pol_flow_match = selinux_xfrm_state_pol_flow_match,
|
|
|
|
.xfrm_decode_session = selinux_xfrm_decode_session,
|
2005-04-16 22:20:36 +00:00
|
|
|
#endif
|
2006-06-22 21:47:17 +00:00
|
|
|
|
|
|
|
#ifdef CONFIG_KEYS
|
2008-04-17 17:17:49 +00:00
|
|
|
.key_alloc = selinux_key_alloc,
|
|
|
|
.key_free = selinux_key_free,
|
|
|
|
.key_permission = selinux_key_permission,
|
2008-04-29 08:01:26 +00:00
|
|
|
.key_getsecurity = selinux_key_getsecurity,
|
2006-06-22 21:47:17 +00:00
|
|
|
#endif
|
2008-03-01 20:03:14 +00:00
|
|
|
|
|
|
|
#ifdef CONFIG_AUDIT
|
|
|
|
.audit_rule_init = selinux_audit_rule_init,
|
|
|
|
.audit_rule_known = selinux_audit_rule_known,
|
|
|
|
.audit_rule_match = selinux_audit_rule_match,
|
|
|
|
.audit_rule_free = selinux_audit_rule_free,
|
|
|
|
#endif
|
2005-04-16 22:20:36 +00:00
|
|
|
};
|
|
|
|
|
|
|
|
static __init int selinux_init(void)
|
|
|
|
{
|
2008-03-06 16:09:10 +00:00
|
|
|
if (!security_module_enable(&selinux_ops)) {
|
|
|
|
selinux_enabled = 0;
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
2005-04-16 22:20:36 +00:00
|
|
|
if (!selinux_enabled) {
|
|
|
|
printk(KERN_INFO "SELinux: Disabled at boot.\n");
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
|
|
|
printk(KERN_INFO "SELinux: Initializing.\n");
|
|
|
|
|
|
|
|
/* Set the security state for the initial task. */
|
CRED: Inaugurate COW credentials
Inaugurate copy-on-write credentials management. This uses RCU to manage the
credentials pointer in the task_struct with respect to accesses by other tasks.
A process may only modify its own credentials, and so does not need locking to
access or modify its own credentials.
A mutex (cred_replace_mutex) is added to the task_struct to control the effect
of PTRACE_ATTACHED on credential calculations, particularly with respect to
execve().
With this patch, the contents of an active credentials struct may not be
changed directly; rather a new set of credentials must be prepared, modified
and committed using something like the following sequence of events:
struct cred *new = prepare_creds();
int ret = blah(new);
if (ret < 0) {
abort_creds(new);
return ret;
}
return commit_creds(new);
There are some exceptions to this rule: the keyrings pointed to by the active
credentials may be instantiated - keyrings violate the COW rule as managing
COW keyrings is tricky, given that it is possible for a task to directly alter
the keys in a keyring in use by another task.
To help enforce this, various pointers to sets of credentials, such as those in
the task_struct, are declared const. The purpose of this is compile-time
discouragement of altering credentials through those pointers. Once a set of
credentials has been made public through one of these pointers, it may not be
modified, except under special circumstances:
(1) Its reference count may incremented and decremented.
(2) The keyrings to which it points may be modified, but not replaced.
The only safe way to modify anything else is to create a replacement and commit
using the functions described in Documentation/credentials.txt (which will be
added by a later patch).
This patch and the preceding patches have been tested with the LTP SELinux
testsuite.
This patch makes several logical sets of alteration:
(1) execve().
This now prepares and commits credentials in various places in the
security code rather than altering the current creds directly.
(2) Temporary credential overrides.
do_coredump() and sys_faccessat() now prepare their own credentials and
temporarily override the ones currently on the acting thread, whilst
preventing interference from other threads by holding cred_replace_mutex
on the thread being dumped.
This will be replaced in a future patch by something that hands down the
credentials directly to the functions being called, rather than altering
the task's objective credentials.
(3) LSM interface.
A number of functions have been changed, added or removed:
(*) security_capset_check(), ->capset_check()
(*) security_capset_set(), ->capset_set()
Removed in favour of security_capset().
(*) security_capset(), ->capset()
New. This is passed a pointer to the new creds, a pointer to the old
creds and the proposed capability sets. It should fill in the new
creds or return an error. All pointers, barring the pointer to the
new creds, are now const.
(*) security_bprm_apply_creds(), ->bprm_apply_creds()
Changed; now returns a value, which will cause the process to be
killed if it's an error.
(*) security_task_alloc(), ->task_alloc_security()
Removed in favour of security_prepare_creds().
(*) security_cred_free(), ->cred_free()
New. Free security data attached to cred->security.
(*) security_prepare_creds(), ->cred_prepare()
New. Duplicate any security data attached to cred->security.
(*) security_commit_creds(), ->cred_commit()
New. Apply any security effects for the upcoming installation of new
security by commit_creds().
(*) security_task_post_setuid(), ->task_post_setuid()
Removed in favour of security_task_fix_setuid().
(*) security_task_fix_setuid(), ->task_fix_setuid()
Fix up the proposed new credentials for setuid(). This is used by
cap_set_fix_setuid() to implicitly adjust capabilities in line with
setuid() changes. Changes are made to the new credentials, rather
than the task itself as in security_task_post_setuid().
(*) security_task_reparent_to_init(), ->task_reparent_to_init()
Removed. Instead the task being reparented to init is referred
directly to init's credentials.
NOTE! This results in the loss of some state: SELinux's osid no
longer records the sid of the thread that forked it.
(*) security_key_alloc(), ->key_alloc()
(*) security_key_permission(), ->key_permission()
Changed. These now take cred pointers rather than task pointers to
refer to the security context.
(4) sys_capset().
This has been simplified and uses less locking. The LSM functions it
calls have been merged.
(5) reparent_to_kthreadd().
This gives the current thread the same credentials as init by simply using
commit_thread() to point that way.
(6) __sigqueue_alloc() and switch_uid()
__sigqueue_alloc() can't stop the target task from changing its creds
beneath it, so this function gets a reference to the currently applicable
user_struct which it then passes into the sigqueue struct it returns if
successful.
switch_uid() is now called from commit_creds(), and possibly should be
folded into that. commit_creds() should take care of protecting
__sigqueue_alloc().
(7) [sg]et[ug]id() and co and [sg]et_current_groups.
The set functions now all use prepare_creds(), commit_creds() and
abort_creds() to build and check a new set of credentials before applying
it.
security_task_set[ug]id() is called inside the prepared section. This
guarantees that nothing else will affect the creds until we've finished.
The calling of set_dumpable() has been moved into commit_creds().
Much of the functionality of set_user() has been moved into
commit_creds().
The get functions all simply access the data directly.
(8) security_task_prctl() and cap_task_prctl().
security_task_prctl() has been modified to return -ENOSYS if it doesn't
want to handle a function, or otherwise return the return value directly
rather than through an argument.
Additionally, cap_task_prctl() now prepares a new set of credentials, even
if it doesn't end up using it.
(9) Keyrings.
A number of changes have been made to the keyrings code:
(a) switch_uid_keyring(), copy_keys(), exit_keys() and suid_keys() have
all been dropped and built in to the credentials functions directly.
They may want separating out again later.
(b) key_alloc() and search_process_keyrings() now take a cred pointer
rather than a task pointer to specify the security context.
(c) copy_creds() gives a new thread within the same thread group a new
thread keyring if its parent had one, otherwise it discards the thread
keyring.
(d) The authorisation key now points directly to the credentials to extend
the search into rather pointing to the task that carries them.
(e) Installing thread, process or session keyrings causes a new set of
credentials to be created, even though it's not strictly necessary for
process or session keyrings (they're shared).
(10) Usermode helper.
The usermode helper code now carries a cred struct pointer in its
subprocess_info struct instead of a new session keyring pointer. This set
of credentials is derived from init_cred and installed on the new process
after it has been cloned.
call_usermodehelper_setup() allocates the new credentials and
call_usermodehelper_freeinfo() discards them if they haven't been used. A
special cred function (prepare_usermodeinfo_creds()) is provided
specifically for call_usermodehelper_setup() to call.
call_usermodehelper_setkeys() adjusts the credentials to sport the
supplied keyring as the new session keyring.
(11) SELinux.
SELinux has a number of changes, in addition to those to support the LSM
interface changes mentioned above:
(a) selinux_setprocattr() no longer does its check for whether the
current ptracer can access processes with the new SID inside the lock
that covers getting the ptracer's SID. Whilst this lock ensures that
the check is done with the ptracer pinned, the result is only valid
until the lock is released, so there's no point doing it inside the
lock.
(12) is_single_threaded().
This function has been extracted from selinux_setprocattr() and put into
a file of its own in the lib/ directory as join_session_keyring() now
wants to use it too.
The code in SELinux just checked to see whether a task shared mm_structs
with other tasks (CLONE_VM), but that isn't good enough. We really want
to know if they're part of the same thread group (CLONE_THREAD).
(13) nfsd.
The NFS server daemon now has to use the COW credentials to set the
credentials it is going to use. It really needs to pass the credentials
down to the functions it calls, but it can't do that until other patches
in this series have been applied.
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: James Morris <jmorris@namei.org>
Signed-off-by: James Morris <jmorris@namei.org>
2008-11-13 23:39:23 +00:00
|
|
|
cred_init_security();
|
2005-04-16 22:20:36 +00:00
|
|
|
|
selinux: generalize disabling of execmem for plt-in-heap archs
On Tue, 2010-04-27 at 11:47 -0700, David Miller wrote:
> From: "Tom \"spot\" Callaway" <tcallawa@redhat.com>
> Date: Tue, 27 Apr 2010 14:20:21 -0400
>
> > [root@apollo ~]$ cat /proc/2174/maps
> > 00010000-00014000 r-xp 00000000 fd:00 15466577
> > /sbin/mingetty
> > 00022000-00024000 rwxp 00002000 fd:00 15466577
> > /sbin/mingetty
> > 00024000-00046000 rwxp 00000000 00:00 0
> > [heap]
>
> SELINUX probably barfs on the executable heap, the PLT is in the HEAP
> just like powerpc32 and that's why VM_DATA_DEFAULT_FLAGS has to set
> both executable and writable.
>
> You also can't remove the CONFIG_PPC32 ifdefs in selinux, since
> because of the VM_DATA_DEFAULT_FLAGS setting used still in that arch,
> the heap will always have executable permission, just like sparc does.
> You have to support those binaries forever, whether you like it or not.
>
> Let's just replace the CONFIG_PPC32 ifdef in SELINUX with CONFIG_PPC32
> || CONFIG_SPARC as in Tom's original patch and let's be done with
> this.
>
> In fact I would go through all the arch/ header files and check the
> VM_DATA_DEFAULT_FLAGS settings and add the necessary new ifdefs to the
> SELINUX code so that other platforms don't have the pain of having to
> go through this process too.
To avoid maintaining per-arch ifdefs, it seems that we could just
directly use (VM_DATA_DEFAULT_FLAGS & VM_EXEC) as the basis for deciding
whether to enable or disable these checks. VM_DATA_DEFAULT_FLAGS isn't
constant on some architectures but instead depends on
current->personality, but we want this applied uniformly. So we'll just
use the initial task state to determine whether or not to enable these
checks.
Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov>
Acked-by: David S. Miller <davem@davemloft.net>
Signed-off-by: James Morris <jmorris@namei.org>
2010-04-28 19:57:57 +00:00
|
|
|
default_noexec = !(VM_DATA_DEFAULT_FLAGS & VM_EXEC);
|
|
|
|
|
2006-03-22 08:09:22 +00:00
|
|
|
sel_inode_cache = kmem_cache_create("selinux_inode_security",
|
|
|
|
sizeof(struct inode_security_struct),
|
2007-07-20 01:11:58 +00:00
|
|
|
0, SLAB_PANIC, NULL);
|
2005-04-16 22:20:36 +00:00
|
|
|
avc_init();
|
|
|
|
|
2008-04-17 17:17:49 +00:00
|
|
|
if (register_security(&selinux_ops))
|
2005-04-16 22:20:36 +00:00
|
|
|
panic("SELinux: Unable to register with kernel.\n");
|
|
|
|
|
2008-04-17 17:17:49 +00:00
|
|
|
if (selinux_enforcing)
|
2007-02-22 23:11:31 +00:00
|
|
|
printk(KERN_DEBUG "SELinux: Starting in enforcing mode\n");
|
2008-04-17 17:17:49 +00:00
|
|
|
else
|
2007-02-22 23:11:31 +00:00
|
|
|
printk(KERN_DEBUG "SELinux: Starting in permissive mode\n");
|
2006-06-22 21:47:17 +00:00
|
|
|
|
2005-04-16 22:20:36 +00:00
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
2010-03-23 10:36:54 +00:00
|
|
|
static void delayed_superblock_init(struct super_block *sb, void *unused)
|
|
|
|
{
|
|
|
|
superblock_doinit(sb, NULL);
|
|
|
|
}
|
|
|
|
|
2005-04-16 22:20:36 +00:00
|
|
|
void selinux_complete_init(void)
|
|
|
|
{
|
2007-02-22 23:11:31 +00:00
|
|
|
printk(KERN_DEBUG "SELinux: Completing initialization.\n");
|
2005-04-16 22:20:36 +00:00
|
|
|
|
|
|
|
/* Set up any superblocks initialized prior to the policy load. */
|
2007-02-22 23:11:31 +00:00
|
|
|
printk(KERN_DEBUG "SELinux: Setting up existing superblocks.\n");
|
2010-03-23 10:36:54 +00:00
|
|
|
iterate_supers(delayed_superblock_init, NULL);
|
2005-04-16 22:20:36 +00:00
|
|
|
}
|
|
|
|
|
|
|
|
/* SELinux requires early initialization in order to label
|
|
|
|
all processes and objects when they are created. */
|
|
|
|
security_initcall(selinux_init);
|
|
|
|
|
2006-02-05 07:27:50 +00:00
|
|
|
#if defined(CONFIG_NETFILTER)
|
2005-04-16 22:20:36 +00:00
|
|
|
|
2008-01-29 13:49:27 +00:00
|
|
|
static struct nf_hook_ops selinux_ipv4_ops[] = {
|
|
|
|
{
|
|
|
|
.hook = selinux_ipv4_postroute,
|
|
|
|
.owner = THIS_MODULE,
|
2012-05-14 03:56:39 +00:00
|
|
|
.pf = NFPROTO_IPV4,
|
2008-01-29 13:49:27 +00:00
|
|
|
.hooknum = NF_INET_POST_ROUTING,
|
|
|
|
.priority = NF_IP_PRI_SELINUX_LAST,
|
|
|
|
},
|
|
|
|
{
|
|
|
|
.hook = selinux_ipv4_forward,
|
|
|
|
.owner = THIS_MODULE,
|
2012-05-14 03:56:39 +00:00
|
|
|
.pf = NFPROTO_IPV4,
|
2008-01-29 13:49:27 +00:00
|
|
|
.hooknum = NF_INET_FORWARD,
|
|
|
|
.priority = NF_IP_PRI_SELINUX_FIRST,
|
2008-10-10 14:16:32 +00:00
|
|
|
},
|
|
|
|
{
|
|
|
|
.hook = selinux_ipv4_output,
|
|
|
|
.owner = THIS_MODULE,
|
2012-05-14 03:56:39 +00:00
|
|
|
.pf = NFPROTO_IPV4,
|
2008-10-10 14:16:32 +00:00
|
|
|
.hooknum = NF_INET_LOCAL_OUT,
|
|
|
|
.priority = NF_IP_PRI_SELINUX_FIRST,
|
2008-01-29 13:49:27 +00:00
|
|
|
}
|
2005-04-16 22:20:36 +00:00
|
|
|
};
|
|
|
|
|
|
|
|
#if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
|
|
|
|
|
2008-01-29 13:49:27 +00:00
|
|
|
static struct nf_hook_ops selinux_ipv6_ops[] = {
|
|
|
|
{
|
|
|
|
.hook = selinux_ipv6_postroute,
|
|
|
|
.owner = THIS_MODULE,
|
2012-05-14 03:56:39 +00:00
|
|
|
.pf = NFPROTO_IPV6,
|
2008-01-29 13:49:27 +00:00
|
|
|
.hooknum = NF_INET_POST_ROUTING,
|
|
|
|
.priority = NF_IP6_PRI_SELINUX_LAST,
|
|
|
|
},
|
|
|
|
{
|
|
|
|
.hook = selinux_ipv6_forward,
|
|
|
|
.owner = THIS_MODULE,
|
2012-05-14 03:56:39 +00:00
|
|
|
.pf = NFPROTO_IPV6,
|
2008-01-29 13:49:27 +00:00
|
|
|
.hooknum = NF_INET_FORWARD,
|
|
|
|
.priority = NF_IP6_PRI_SELINUX_FIRST,
|
|
|
|
}
|
2005-04-16 22:20:36 +00:00
|
|
|
};
|
|
|
|
|
|
|
|
#endif /* IPV6 */
|
|
|
|
|
|
|
|
static int __init selinux_nf_ip_init(void)
|
|
|
|
{
|
|
|
|
int err = 0;
|
|
|
|
|
|
|
|
if (!selinux_enabled)
|
|
|
|
goto out;
|
2007-02-22 23:11:31 +00:00
|
|
|
|
|
|
|
printk(KERN_DEBUG "SELinux: Registering netfilter hooks\n");
|
|
|
|
|
2008-07-27 00:48:15 +00:00
|
|
|
err = nf_register_hooks(selinux_ipv4_ops, ARRAY_SIZE(selinux_ipv4_ops));
|
|
|
|
if (err)
|
|
|
|
panic("SELinux: nf_register_hooks for IPv4: error %d\n", err);
|
2005-04-16 22:20:36 +00:00
|
|
|
|
|
|
|
#if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
|
2008-07-27 00:48:15 +00:00
|
|
|
err = nf_register_hooks(selinux_ipv6_ops, ARRAY_SIZE(selinux_ipv6_ops));
|
|
|
|
if (err)
|
|
|
|
panic("SELinux: nf_register_hooks for IPv6: error %d\n", err);
|
2005-04-16 22:20:36 +00:00
|
|
|
#endif /* IPV6 */
|
[LSM-IPSec]: Per-packet access control.
This patch series implements per packet access control via the
extension of the Linux Security Modules (LSM) interface by hooks in
the XFRM and pfkey subsystems that leverage IPSec security
associations to label packets. Extensions to the SELinux LSM are
included that leverage the patch for this purpose.
This patch implements the changes necessary to the SELinux LSM to
create, deallocate, and use security contexts for policies
(xfrm_policy) and security associations (xfrm_state) that enable
control of a socket's ability to send and receive packets.
Patch purpose:
The patch is designed to enable the SELinux LSM to implement access
control on individual packets based on the strongly authenticated
IPSec security association. Such access controls augment the existing
ones in SELinux based on network interface and IP address. The former
are very coarse-grained, and the latter can be spoofed. By using
IPSec, the SELinux can control access to remote hosts based on
cryptographic keys generated using the IPSec mechanism. This enables
access control on a per-machine basis or per-application if the remote
machine is running the same mechanism and trusted to enforce the
access control policy.
Patch design approach:
The patch's main function is to authorize a socket's access to a IPSec
policy based on their security contexts. Since the communication is
implemented by a security association, the patch ensures that the
security association's negotiated and used have the same security
context. The patch enables allocation and deallocation of such
security contexts for policies and security associations. It also
enables copying of the security context when policies are cloned.
Lastly, the patch ensures that packets that are sent without using a
IPSec security assocation with a security context are allowed to be
sent in that manner.
A presentation available at
www.selinux-symposium.org/2005/presentations/session2/2-3-jaeger.pdf
from the SELinux symposium describes the overall approach.
Patch implementation details:
The function which authorizes a socket to perform a requested
operation (send/receive) on a IPSec policy (xfrm_policy) is
selinux_xfrm_policy_lookup. The Netfilter and rcv_skb hooks ensure
that if a IPSec SA with a securit y association has not been used,
then the socket is allowed to send or receive the packet,
respectively.
The patch implements SELinux function for allocating security contexts
when policies (xfrm_policy) are created via the pfkey or xfrm_user
interfaces via selinux_xfrm_policy_alloc. When a security association
is built, SELinux allocates the security context designated by the
XFRM subsystem which is based on that of the authorized policy via
selinux_xfrm_state_alloc.
When a xfrm_policy is cloned, the security context of that policy, if
any, is copied to the clone via selinux_xfrm_policy_clone.
When a xfrm_policy or xfrm_state is freed, its security context, if
any is also freed at selinux_xfrm_policy_free or
selinux_xfrm_state_free.
Testing:
The SELinux authorization function is tested using ipsec-tools. We
created policies and security associations with particular security
contexts and added SELinux access control policy entries to verify the
authorization decision. We also made sure that packets for which no
security context was supplied (which either did or did not use
security associations) were authorized using an unlabelled context.
Signed-off-by: Trent Jaeger <tjaeger@cse.psu.edu>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
2005-12-14 07:12:40 +00:00
|
|
|
|
2005-04-16 22:20:36 +00:00
|
|
|
out:
|
|
|
|
return err;
|
|
|
|
}
|
|
|
|
|
|
|
|
__initcall(selinux_nf_ip_init);
|
|
|
|
|
|
|
|
#ifdef CONFIG_SECURITY_SELINUX_DISABLE
|
|
|
|
static void selinux_nf_ip_exit(void)
|
|
|
|
{
|
2007-02-22 23:11:31 +00:00
|
|
|
printk(KERN_DEBUG "SELinux: Unregistering netfilter hooks\n");
|
2005-04-16 22:20:36 +00:00
|
|
|
|
2008-07-27 00:48:15 +00:00
|
|
|
nf_unregister_hooks(selinux_ipv4_ops, ARRAY_SIZE(selinux_ipv4_ops));
|
2005-04-16 22:20:36 +00:00
|
|
|
#if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
|
2008-07-27 00:48:15 +00:00
|
|
|
nf_unregister_hooks(selinux_ipv6_ops, ARRAY_SIZE(selinux_ipv6_ops));
|
2005-04-16 22:20:36 +00:00
|
|
|
#endif /* IPV6 */
|
|
|
|
}
|
|
|
|
#endif
|
|
|
|
|
2006-02-05 07:27:50 +00:00
|
|
|
#else /* CONFIG_NETFILTER */
|
2005-04-16 22:20:36 +00:00
|
|
|
|
|
|
|
#ifdef CONFIG_SECURITY_SELINUX_DISABLE
|
|
|
|
#define selinux_nf_ip_exit()
|
|
|
|
#endif
|
|
|
|
|
2006-02-05 07:27:50 +00:00
|
|
|
#endif /* CONFIG_NETFILTER */
|
2005-04-16 22:20:36 +00:00
|
|
|
|
|
|
|
#ifdef CONFIG_SECURITY_SELINUX_DISABLE
|
2008-04-17 17:17:49 +00:00
|
|
|
static int selinux_disabled;
|
|
|
|
|
2005-04-16 22:20:36 +00:00
|
|
|
int selinux_disable(void)
|
|
|
|
{
|
|
|
|
if (ss_initialized) {
|
|
|
|
/* Not permitted after initial policy load. */
|
|
|
|
return -EINVAL;
|
|
|
|
}
|
|
|
|
|
|
|
|
if (selinux_disabled) {
|
|
|
|
/* Only do this once. */
|
|
|
|
return -EINVAL;
|
|
|
|
}
|
|
|
|
|
|
|
|
printk(KERN_INFO "SELinux: Disabled at runtime.\n");
|
|
|
|
|
|
|
|
selinux_disabled = 1;
|
2006-05-03 14:52:36 +00:00
|
|
|
selinux_enabled = 0;
|
2005-04-16 22:20:36 +00:00
|
|
|
|
2010-02-23 15:15:28 +00:00
|
|
|
reset_security_ops();
|
2005-04-16 22:20:36 +00:00
|
|
|
|
2009-09-21 01:23:01 +00:00
|
|
|
/* Try to destroy the avc node cache */
|
|
|
|
avc_disable();
|
|
|
|
|
2005-04-16 22:20:36 +00:00
|
|
|
/* Unregister netfilter hooks. */
|
|
|
|
selinux_nf_ip_exit();
|
|
|
|
|
|
|
|
/* Unregister selinuxfs. */
|
|
|
|
exit_sel_fs();
|
|
|
|
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
#endif
|