linux/mm
David Howells 5cd9c58fbe 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 22:59:43 +10:00
..
allocpercpu.c mm/allocpercpu.c: make 4 functions static 2008-07-26 12:00:12 -07:00
backing-dev.c mm: bdi: fix race in bdi_class device creation 2008-05-20 13:31:53 -07:00
bootmem.c bootmem: replace node_boot_start in struct bootmem_data 2008-07-24 10:47:20 -07:00
bounce.c block: Initial support for data-less (or empty) barrier support 2007-10-16 11:03:56 +02:00
dmapool.c dmapool: enable debugging for CONFIG_SLUB_DEBUG_ON too 2008-04-28 08:58:20 -07:00
fadvise.c xip: support non-struct page backed memory 2008-04-28 08:58:23 -07:00
filemap_xip.c mmu-notifiers: core 2008-07-28 16:30:21 -07:00
filemap.c mm: rename page trylock 2008-08-04 21:31:34 -07:00
fremap.c mmu-notifiers: core 2008-07-28 16:30:21 -07:00
highmem.c highmem: Export totalhigh_pages. 2008-07-19 22:39:46 -07:00
hugetlb.c allocate structures for reservation tracking in hugetlbfs outside of spinlocks v2 2008-08-12 16:07:28 -07:00
internal.h mm: export prep_compound_page to mm 2008-07-24 10:47:17 -07:00
Kconfig mm: Make generic weak get_user_pages_fast and EXPORT_GPL it 2008-08-12 17:52:53 +10:00
maccess.c kgdb: fix optional arch functions and probe_kernel_* 2008-04-17 20:05:39 +02:00
madvise.c madvise: update function comment of madvise_dontneed 2008-07-30 09:41:45 -07:00
Makefile mmu-notifiers: core 2008-07-28 16:30:21 -07:00
memcontrol.c memcg: fix oops in mem_cgroup_shrink_usage 2008-08-12 16:07:28 -07:00
memory_hotplug.c memory-hotplug: add sysfs removable attribute for hotplug memory remove 2008-07-24 10:47:21 -07:00
memory.c mm: rename page trylock 2008-08-04 21:31:34 -07:00
mempolicy.c do_migrate_pages(): remove unused variable 2008-08-12 16:07:29 -07:00
mempool.c spelling fixes: mm/ 2007-10-20 01:27:18 +02:00
migrate.c mm: rename page trylock 2008-08-04 21:31:34 -07:00
mincore.c mm: remove nopage 2008-04-28 08:58:18 -07:00
mlock.c mlock() fix return values 2008-08-04 16:58:45 -07:00
mm_init.c mm_init.c: avoid ifdef-inside-macro-expansion 2008-08-05 14:33:46 -07:00
mmap.c Merge branch 'core/locking' into core/urgent 2008-08-12 00:11:49 +02:00
mmu_notifier.c mmu-notifiers: core 2008-07-28 16:30:21 -07:00
mmzone.c mm: filter based on a nodemask as well as a gfp_mask 2008-04-28 08:58:19 -07:00
mprotect.c mmu-notifiers: core 2008-07-28 16:30:21 -07:00
mremap.c mmu-notifiers: core 2008-07-28 16:30:21 -07:00
msync.c Detach sched.h from mm.h 2007-05-21 09:18:19 -07:00
nommu.c nommu: Provide vmalloc_exec(). 2008-08-04 16:01:47 +09:00
oom_kill.c security: Fix setting of PF_SUPERPRIV by __capable() 2008-08-14 22:59:43 +10:00
page_alloc.c page allocator: use no-panic variant of alloc_bootmem() in alloc_large_system_hash() 2008-08-12 16:07:27 -07:00
page_io.c mm: fix PageUptodate data race 2008-02-05 09:44:19 -08:00
page_isolation.c memory hotremove: unset migrate type "ISOLATE" after removal 2007-11-14 18:45:38 -08:00
page-writeback.c mm: spinlock tree_lock 2008-07-26 12:00:06 -07:00
pagewalk.c pagemap: pass mm into pagewalkers 2008-06-12 18:05:41 -07:00
pdflush.c pdflush: use time_after() instead of open-coding it 2008-07-25 10:53:28 -07:00
prio_tree.c spelling fixes: mm/ 2007-10-20 01:27:18 +02:00
quicklist.c quicklists: Only consider memory that can be used with GFP_KERNEL 2008-01-14 08:52:22 -08:00
readahead.c mm: readahead scan lockless 2008-07-26 12:00:06 -07:00
rmap.c mm: rename page trylock 2008-08-04 21:31:34 -07:00
shmem_acl.c [PATCH] sanitize ->permission() prototype 2008-07-26 20:53:14 -04:00
shmem.c mm: rename page trylock 2008-08-04 21:31:34 -07:00
slab.c mm: unexport ksize 2008-07-29 23:44:26 +03:00
slob.c mm: unexport ksize 2008-07-29 23:44:26 +03:00
slub.c SLUB: dynamic per-cache MIN_PARTIAL 2008-08-05 09:28:47 +03:00
sparse-vmemmap.c Christoph has moved 2008-07-04 10:40:04 -07:00
sparse.c mm/sparse.c: removed duplicated include 2008-08-12 16:07:30 -07:00
swap_state.c mm: rename page trylock 2008-08-04 21:31:34 -07:00
swap.c mm: rename page trylock 2008-08-04 21:31:34 -07:00
swapfile.c mm: rename page trylock 2008-08-04 21:31:34 -07:00
thrash.c Bug in mm/thrash.c function grab_swap_token() 2007-05-11 08:29:32 -07:00
tiny-shmem.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6 2008-03-25 08:57:47 -07:00
truncate.c mm: rename page trylock 2008-08-04 21:31:34 -07:00
util.c mm: Make generic weak get_user_pages_fast and EXPORT_GPL it 2008-08-12 17:52:53 +10:00
vmalloc.c Use WARN() in mm/vmalloc.c 2008-07-26 12:00:07 -07:00
vmscan.c mm: rename page trylock 2008-08-04 21:31:34 -07:00
vmstat.c mm/vmstat.c: proper externs 2008-07-24 10:47:14 -07:00