This fixes CVE-2017-7472.
Running the following program as an unprivileged user exhausts kernel
memory by leaking thread keyrings:
#include <keyutils.h>
int main()
{
for (;;)
keyctl_set_reqkey_keyring(KEY_REQKEY_DEFL_THREAD_KEYRING);
}
Fix it by only creating a new thread keyring if there wasn't one before.
To make things more consistent, make install_thread_keyring_to_cred()
and install_process_keyring_to_cred() both return 0 if the corresponding
keyring is already present.
Fixes: d84f4f992c ("CRED: Inaugurate COW credentials")
Cc: stable@vger.kernel.org # 2.6.29+
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: David Howells <dhowells@redhat.com>
This fixes CVE-2017-6951.
Userspace should not be able to do things with the "dead" key type as it
doesn't have some of the helper functions set upon it that the kernel
needs. Attempting to use it may cause the kernel to crash.
Fix this by changing the name of the type to ".dead" so that it's rejected
up front on userspace syscalls by key_get_type_from_user().
Though this doesn't seem to affect recent kernels, it does affect older
ones, certainly those prior to:
commit c06cfb08b8
Author: David Howells <dhowells@redhat.com>
Date: Tue Sep 16 17:36:06 2014 +0100
KEYS: Remove key_type::match in favour of overriding default by match_preparse
which went in before 3.18-rc1.
Signed-off-by: David Howells <dhowells@redhat.com>
cc: stable@vger.kernel.org
This fixes CVE-2016-9604.
Keyrings whose name begin with a '.' are special internal keyrings and so
userspace isn't allowed to create keyrings by this name to prevent
shadowing. However, the patch that added the guard didn't fix
KEYCTL_JOIN_SESSION_KEYRING. Not only can that create dot-named keyrings,
it can also subscribe to them as a session keyring if they grant SEARCH
permission to the user.
This, for example, allows a root process to set .builtin_trusted_keys as
its session keyring, at which point it has full access because now the
possessor permissions are added. This permits root to add extra public
keys, thereby bypassing module verification.
This also affects kexec and IMA.
This can be tested by (as root):
keyctl session .builtin_trusted_keys
keyctl add user a a @s
keyctl list @s
which on my test box gives me:
2 keys in keyring:
180010936: ---lswrv 0 0 asymmetric: Build time autogenerated kernel key: ae3d4a31b82daa8e1a75b49dc2bba949fd992a05
801382539: --alswrv 0 0 user: a
Fix this by rejecting names beginning with a '.' in the keyctl.
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
cc: linux-ima-devel@lists.sourceforge.net
cc: stable@vger.kernel.org
Pull sched.h split-up from Ingo Molnar:
"The point of these changes is to significantly reduce the
<linux/sched.h> header footprint, to speed up the kernel build and to
have a cleaner header structure.
After these changes the new <linux/sched.h>'s typical preprocessed
size goes down from a previous ~0.68 MB (~22K lines) to ~0.45 MB (~15K
lines), which is around 40% faster to build on typical configs.
Not much changed from the last version (-v2) posted three weeks ago: I
eliminated quirks, backmerged fixes plus I rebased it to an upstream
SHA1 from yesterday that includes most changes queued up in -next plus
all sched.h changes that were pending from Andrew.
I've re-tested the series both on x86 and on cross-arch defconfigs,
and did a bisectability test at a number of random points.
I tried to test as many build configurations as possible, but some
build breakage is probably still left - but it should be mostly
limited to architectures that have no cross-compiler binaries
available on kernel.org, and non-default configurations"
* 'WIP.sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (146 commits)
sched/headers: Clean up <linux/sched.h>
sched/headers: Remove #ifdefs from <linux/sched.h>
sched/headers: Remove the <linux/topology.h> include from <linux/sched.h>
sched/headers, hrtimer: Remove the <linux/wait.h> include from <linux/hrtimer.h>
sched/headers, x86/apic: Remove the <linux/pm.h> header inclusion from <asm/apic.h>
sched/headers, timers: Remove the <linux/sysctl.h> include from <linux/timer.h>
sched/headers: Remove <linux/magic.h> from <linux/sched/task_stack.h>
sched/headers: Remove <linux/sched.h> from <linux/sched/init.h>
sched/core: Remove unused prefetch_stack()
sched/headers: Remove <linux/rculist.h> from <linux/sched.h>
sched/headers: Remove the 'init_pid_ns' prototype from <linux/sched.h>
sched/headers: Remove <linux/signal.h> from <linux/sched.h>
sched/headers: Remove <linux/rwsem.h> from <linux/sched.h>
sched/headers: Remove the runqueue_is_locked() prototype
sched/headers: Remove <linux/sched.h> from <linux/sched/hotplug.h>
sched/headers: Remove <linux/sched.h> from <linux/sched/debug.h>
sched/headers: Remove <linux/sched.h> from <linux/sched/nohz.h>
sched/headers: Remove <linux/sched.h> from <linux/sched/stat.h>
sched/headers: Remove the <linux/gfp.h> include from <linux/sched.h>
sched/headers: Remove <linux/rtmutex.h> from <linux/sched.h>
...
We are going to split <linux/sched/task.h> out of <linux/sched.h>, which
will have to be picked up from other headers and a couple of .c files.
Create a trivial placeholder <linux/sched/task.h> file that just
maps to <linux/sched.h> to make this patch obviously correct and
bisectable.
Include the new header in the files that are going to need it.
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Add #include <linux/cred.h> dependencies to all .c files rely on sched.h
doing that for them.
Note that even if the count where we need to add extra headers seems high,
it's still a net win, because <linux/sched.h> is included in over
2,200 files ...
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
We are going to split <linux/sched/user.h> out of <linux/sched.h>, which
will have to be picked up from other headers and a couple of .c files.
Create a trivial placeholder <linux/sched/user.h> file that just
maps to <linux/sched.h> to make this patch obviously correct and
bisectable.
Include the new header in the files that are going to need it.
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
rcu_dereference_key() and user_key_payload() are currently being used in
two different, incompatible ways:
(1) As a wrapper to rcu_dereference() - when only the RCU read lock used
to protect the key.
(2) As a wrapper to rcu_dereference_protected() - when the key semaphor is
used to protect the key and the may be being modified.
Fix this by splitting both of the key wrappers to produce:
(1) RCU accessors for keys when caller has the key semaphore locked:
dereference_key_locked()
user_key_payload_locked()
(2) RCU accessors for keys when caller holds the RCU read lock:
dereference_key_rcu()
user_key_payload_rcu()
This should fix following warning in the NFS idmapper
===============================
[ INFO: suspicious RCU usage. ]
4.10.0 #1 Tainted: G W
-------------------------------
./include/keys/user-type.h:53 suspicious rcu_dereference_protected() usage!
other info that might help us debug this:
rcu_scheduler_active = 2, debug_locks = 0
1 lock held by mount.nfs/5987:
#0: (rcu_read_lock){......}, at: [<d000000002527abc>] nfs_idmap_get_key+0x15c/0x420 [nfsv4]
stack backtrace:
CPU: 1 PID: 5987 Comm: mount.nfs Tainted: G W 4.10.0 #1
Call Trace:
dump_stack+0xe8/0x154 (unreliable)
lockdep_rcu_suspicious+0x140/0x190
nfs_idmap_get_key+0x380/0x420 [nfsv4]
nfs_map_name_to_uid+0x2a0/0x3b0 [nfsv4]
decode_getfattr_attrs+0xfac/0x16b0 [nfsv4]
decode_getfattr_generic.constprop.106+0xbc/0x150 [nfsv4]
nfs4_xdr_dec_lookup_root+0xac/0xb0 [nfsv4]
rpcauth_unwrap_resp+0xe8/0x140 [sunrpc]
call_decode+0x29c/0x910 [sunrpc]
__rpc_execute+0x140/0x8f0 [sunrpc]
rpc_run_task+0x170/0x200 [sunrpc]
nfs4_call_sync_sequence+0x68/0xa0 [nfsv4]
_nfs4_lookup_root.isra.44+0xd0/0xf0 [nfsv4]
nfs4_lookup_root+0xe0/0x350 [nfsv4]
nfs4_lookup_root_sec+0x70/0xa0 [nfsv4]
nfs4_find_root_sec+0xc4/0x100 [nfsv4]
nfs4_proc_get_rootfh+0x5c/0xf0 [nfsv4]
nfs4_get_rootfh+0x6c/0x190 [nfsv4]
nfs4_server_common_setup+0xc4/0x260 [nfsv4]
nfs4_create_server+0x278/0x3c0 [nfsv4]
nfs4_remote_mount+0x50/0xb0 [nfsv4]
mount_fs+0x74/0x210
vfs_kern_mount+0x78/0x220
nfs_do_root_mount+0xb0/0x140 [nfsv4]
nfs4_try_mount+0x60/0x100 [nfsv4]
nfs_fs_mount+0x5ec/0xda0 [nfs]
mount_fs+0x74/0x210
vfs_kern_mount+0x78/0x220
do_mount+0x254/0xf70
SyS_mount+0x94/0x100
system_call+0x38/0xe0
Reported-by: Jan Stancek <jstancek@redhat.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Tested-by: Jan Stancek <jstancek@redhat.com>
Signed-off-by: James Morris <james.l.morris@oracle.com>
Here is the "small" driver core patches for 4.11-rc1.
Not much here, some firmware documentation and self-test updates, a
debugfs code formatting issue, and a new feature for call_usermodehelper
to make it more robust on systems that want to lock it down in a more
secure way.
All of these have been linux-next for a while now with no reported
issues.
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-----BEGIN PGP SIGNATURE-----
iG0EABECAC0WIQT0tgzFv3jCIUoxPcsxR9QN2y37KQUCWK2jKg8cZ3JlZ0Brcm9h
aC5jb20ACgkQMUfUDdst+ymCEACgozYuqZZ/TUGW0P3xVNi7fbfUWCEAn3nYExrc
XgevqeYOSKp2We6X/2JX
=aZ+5
-----END PGP SIGNATURE-----
Merge tag 'driver-core-4.11-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core
Pull driver core updates from Greg KH:
"Here is the "small" driver core patches for 4.11-rc1.
Not much here, some firmware documentation and self-test updates, a
debugfs code formatting issue, and a new feature for call_usermodehelper
to make it more robust on systems that want to lock it down in a more
secure way.
All of these have been linux-next for a while now with no reported
issues"
* tag 'driver-core-4.11-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core:
kernfs: handle null pointers while printing node name and path
Introduce STATIC_USERMODEHELPER to mediate call_usermodehelper()
Make static usermode helper binaries constant
kmod: make usermodehelper path a const string
firmware: revamp firmware documentation
selftests: firmware: send expected errors to /dev/null
selftests: firmware: only modprobe if driver is missing
platform: Print the resource range if device failed to claim
kref: prefer atomic_inc_not_zero to atomic_add_unless
debugfs: improve formatting of debugfs_real_fops()
I don't think GCC has figured out how to optimize the memset() away, but
they might eventually so let's future proof this code a bit.
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
Signed-off-by: James Morris <james.l.morris@oracle.com>
This function has two callers and neither are able to handle a NULL
return. Really, -EINVAL is the correct thing return here anyway. This
fixes some static checker warnings like:
security/keys/encrypted-keys/encrypted.c:709 encrypted_key_decrypt()
error: uninitialized symbol 'master_key'.
Fixes: 7e70cb4978 ("keys: add new key-type encrypted")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Acked-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
Signed-off-by: James Morris <james.l.morris@oracle.com>
There are a number of usermode helper binaries that are "hard coded" in
the kernel today, so mark them as "const" to make it harder for someone
to change where the variables point to.
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Thomas Sailer <t.sailer@alumni.ethz.ch>
Cc: "Rafael J. Wysocki" <rafael.j.wysocki@intel.com>
Cc: Johan Hovold <johan@kernel.org>
Cc: Alex Elder <elder@kernel.org>
Cc: "J. Bruce Fields" <bfields@fieldses.org>
Cc: Jeff Layton <jlayton@poochiereds.net>
Cc: David Howells <dhowells@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This was entirely automated, using the script by Al:
PATT='^[[:blank:]]*#[[:blank:]]*include[[:blank:]]*<asm/uaccess.h>'
sed -i -e "s!$PATT!#include <linux/uaccess.h>!" \
$(git grep -l "$PATT"|grep -v ^include/linux/uaccess.h)
to do the replacement at the end of the merge window.
Requested-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
copy_from_iter_full(), copy_from_iter_full_nocache() and
csum_and_copy_from_iter_full() - counterparts of copy_from_iter()
et.al., advancing iterator only in case of successful full copy
and returning whether it had been successful or not.
Convert some obvious users. *NOTE* - do not blindly assume that
something is a good candidate for those unless you are sure that
not advancing iov_iter in failure case is the right thing in
this case. Anything that does short read/short write kind of
stuff (or is in a loop, etc.) is unlikely to be a good one.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Since BIG_KEYS can't be compiled as module it requires one of the "stdrng"
providers to be compiled into kernel. Otherwise big_key_crypto_init() fails
on crypto_alloc_rng step and next dereference of big_key_skcipher (e.g. in
big_key_preparse()) results in a NULL pointer dereference.
Fixes: 13100a72f4 ('Security: Keys: Big keys stored encrypted')
Signed-off-by: Artem Savkov <asavkov@redhat.com>
Signed-off-by: David Howells <dhowells@redhat.com>
cc: Stephan Mueller <smueller@chronox.de>
cc: Kirill Marinushkin <k.marinushkin@gmail.com>
cc: stable@vger.kernel.org
Signed-off-by: James Morris <james.l.morris@oracle.com>
big_key has two separate initialisation functions, one that registers the
key type and one that registers the crypto. If the key type fails to
register, there's no problem if the crypto registers successfully because
there's no way to reach the crypto except through the key type.
However, if the key type registers successfully but the crypto does not,
big_key_rng and big_key_blkcipher may end up set to NULL - but the code
neither checks for this nor unregisters the big key key type.
Furthermore, since the key type is registered before the crypto, it is
theoretically possible for the kernel to try adding a big_key before the
crypto is set up, leading to the same effect.
Fix this by merging big_key_crypto_init() and big_key_init() and calling
the resulting function late. If they're going to be encrypted, we
shouldn't be creating big_keys before we have the facilities to do the
encryption available. The key type registration is also moved after the
crypto initialisation.
The fix also includes message printing on failure.
If the big_key type isn't correctly set up, simply doing:
dd if=/dev/zero bs=4096 count=1 | keyctl padd big_key a @s
ought to cause an oops.
Fixes: 13100a72f4 ('Security: Keys: Big keys stored encrypted')
Signed-off-by: David Howells <dhowells@redhat.com>
cc: Peter Hlavaty <zer0mem@yahoo.com>
cc: Kirill Marinushkin <k.marinushkin@gmail.com>
cc: Artem Savkov <asavkov@redhat.com>
cc: stable@vger.kernel.org
Signed-off-by: James Morris <james.l.morris@oracle.com>
This fixes CVE-2016-7042.
Fix a short sprintf buffer in proc_keys_show(). If the gcc stack protector
is turned on, this can cause a panic due to stack corruption.
The problem is that xbuf[] is not big enough to hold a 64-bit timeout
rendered as weeks:
(gdb) p 0xffffffffffffffffULL/(60*60*24*7)
$2 = 30500568904943
That's 14 chars plus NUL, not 11 chars plus NUL.
Expand the buffer to 16 chars.
I think the unpatched code apparently works if the stack-protector is not
enabled because on a 32-bit machine the buffer won't be overflowed and on a
64-bit machine there's a 64-bit aligned pointer at one side and an int that
isn't checked again on the other side.
The panic incurred looks something like:
Kernel panic - not syncing: stack-protector: Kernel stack is corrupted in: ffffffff81352ebe
CPU: 0 PID: 1692 Comm: reproducer Not tainted 4.7.2-201.fc24.x86_64 #1
Hardware name: Red Hat KVM, BIOS 0.5.1 01/01/2011
0000000000000086 00000000fbbd2679 ffff8800a044bc00 ffffffff813d941f
ffffffff81a28d58 ffff8800a044bc98 ffff8800a044bc88 ffffffff811b2cb6
ffff880000000010 ffff8800a044bc98 ffff8800a044bc30 00000000fbbd2679
Call Trace:
[<ffffffff813d941f>] dump_stack+0x63/0x84
[<ffffffff811b2cb6>] panic+0xde/0x22a
[<ffffffff81352ebe>] ? proc_keys_show+0x3ce/0x3d0
[<ffffffff8109f7f9>] __stack_chk_fail+0x19/0x30
[<ffffffff81352ebe>] proc_keys_show+0x3ce/0x3d0
[<ffffffff81350410>] ? key_validate+0x50/0x50
[<ffffffff8134db30>] ? key_default_cmp+0x20/0x20
[<ffffffff8126b31c>] seq_read+0x2cc/0x390
[<ffffffff812b6b12>] proc_reg_read+0x42/0x70
[<ffffffff81244fc7>] __vfs_read+0x37/0x150
[<ffffffff81357020>] ? security_file_permission+0xa0/0xc0
[<ffffffff81246156>] vfs_read+0x96/0x130
[<ffffffff81247635>] SyS_read+0x55/0xc0
[<ffffffff817eb872>] entry_SYSCALL_64_fastpath+0x1a/0xa4
Reported-by: Ondrej Kozina <okozina@redhat.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Tested-by: Ondrej Kozina <okozina@redhat.com>
cc: stable@vger.kernel.org
Signed-off-by: James Morris <james.l.morris@oracle.com>
The IV must not be modified by the skcipher operation so we need
to duplicate it.
Fixes: c3917fd9df ("KEYS: Use skcipher")
Cc: stable@vger.kernel.org
Reported-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Pull security subsystem updates from James Morris:
"Highlights:
- TPM core and driver updates/fixes
- IPv6 security labeling (CALIPSO)
- Lots of Apparmor fixes
- Seccomp: remove 2-phase API, close hole where ptrace can change
syscall #"
* 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security: (156 commits)
apparmor: fix SECURITY_APPARMOR_HASH_DEFAULT parameter handling
tpm: Add TPM 2.0 support to the Nuvoton i2c driver (NPCT6xx family)
tpm: Factor out common startup code
tpm: use devm_add_action_or_reset
tpm2_i2c_nuvoton: add irq validity check
tpm: read burstcount from TPM_STS in one 32-bit transaction
tpm: fix byte-order for the value read by tpm2_get_tpm_pt
tpm_tis_core: convert max timeouts from msec to jiffies
apparmor: fix arg_size computation for when setprocattr is null terminated
apparmor: fix oops, validate buffer size in apparmor_setprocattr()
apparmor: do not expose kernel stack
apparmor: fix module parameters can be changed after policy is locked
apparmor: fix oops in profile_unpack() when policy_db is not present
apparmor: don't check for vmalloc_addr if kvzalloc() failed
apparmor: add missing id bounds check on dfa verification
apparmor: allow SYS_CAP_RESOURCE to be sufficient to prlimit another task
apparmor: use list_next_entry instead of list_entry_next
apparmor: fix refcount race when finding a child profile
apparmor: fix ref count leak when profile sha1 hash is read
apparmor: check that xindex is in trans_table bounds
...
Pull crypto updates from Herbert Xu:
"Here is the crypto update for 4.8:
API:
- first part of skcipher low-level conversions
- add KPP (Key-agreement Protocol Primitives) interface.
Algorithms:
- fix IPsec/cryptd reordering issues that affects aesni
- RSA no longer does explicit leading zero removal
- add SHA3
- add DH
- add ECDH
- improve DRBG performance by not doing CTR by hand
Drivers:
- add x86 AVX2 multibuffer SHA256/512
- add POWER8 optimised crc32c
- add xts support to vmx
- add DH support to qat
- add RSA support to caam
- add Layerscape support to caam
- add SEC1 AEAD support to talitos
- improve performance by chaining requests in marvell/cesa
- add support for Araneus Alea I USB RNG
- add support for Broadcom BCM5301 RNG
- add support for Amlogic Meson RNG
- add support Broadcom NSP SoC RNG"
* 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6: (180 commits)
crypto: vmx - Fix aes_p8_xts_decrypt build failure
crypto: vmx - Ignore generated files
crypto: vmx - Adding support for XTS
crypto: vmx - Adding asm subroutines for XTS
crypto: skcipher - add comment for skcipher_alg->base
crypto: testmgr - Print akcipher algorithm name
crypto: marvell - Fix wrong flag used for GFP in mv_cesa_dma_add_iv_op
crypto: nx - off by one bug in nx_of_update_msc()
crypto: rsa-pkcs1pad - fix rsa-pkcs1pad request struct
crypto: scatterwalk - Inline start/map/done
crypto: scatterwalk - Remove unnecessary BUG in scatterwalk_start
crypto: scatterwalk - Remove unnecessary advance in scatterwalk_pagedone
crypto: scatterwalk - Fix test in scatterwalk_done
crypto: api - Optimise away crypto_yield when hard preemption is on
crypto: scatterwalk - add no-copy support to copychunks
crypto: scatterwalk - Remove scatterwalk_bytes_sglen
crypto: omap - Stop using crypto scatterwalk_bytes_sglen
crypto: skcipher - Remove top-level givcipher interface
crypto: user - Remove crypto_lookup_skcipher call
crypto: cts - Convert to skcipher
...
This patch replaces use of the obsolete blkcipher with skcipher.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Acked-by: David Howells <dhowells@redhat.com>
If __key_link_begin() failed then "edit" would be uninitialized. I've
added a check to fix that.
This allows a random user to crash the kernel, though it's quite
difficult to achieve. There are three ways it can be done as the user
would have to cause an error to occur in __key_link():
(1) Cause the kernel to run out of memory. In practice, this is difficult
to achieve without ENOMEM cropping up elsewhere and aborting the
attempt.
(2) Revoke the destination keyring between the keyring ID being looked up
and it being tested for revocation. In practice, this is difficult to
time correctly because the KEYCTL_REJECT function can only be used
from the request-key upcall process. Further, users can only make use
of what's in /sbin/request-key.conf, though this does including a
rejection debugging test - which means that the destination keyring
has to be the caller's session keyring in practice.
(3) Have just enough key quota available to create a key, a new session
keyring for the upcall and a link in the session keyring, but not then
sufficient quota to create a link in the nominated destination keyring
so that it fails with EDQUOT.
The bug can be triggered using option (3) above using something like the
following:
echo 80 >/proc/sys/kernel/keys/root_maxbytes
keyctl request2 user debug:fred negate @t
The above sets the quota to something much lower (80) to make the bug
easier to trigger, but this is dependent on the system. Note also that
the name of the keyring created contains a random number that may be
between 1 and 10 characters in size, so may throw the test off by
changing the amount of quota used.
Assuming the failure occurs, something like the following will be seen:
kfree_debugcheck: out of range ptr 6b6b6b6b6b6b6b68h
------------[ cut here ]------------
kernel BUG at ../mm/slab.c:2821!
...
RIP: 0010:[<ffffffff811600f9>] kfree_debugcheck+0x20/0x25
RSP: 0018:ffff8804014a7de8 EFLAGS: 00010092
RAX: 0000000000000034 RBX: 6b6b6b6b6b6b6b68 RCX: 0000000000000000
RDX: 0000000000040001 RSI: 00000000000000f6 RDI: 0000000000000300
RBP: ffff8804014a7df0 R08: 0000000000000001 R09: 0000000000000000
R10: ffff8804014a7e68 R11: 0000000000000054 R12: 0000000000000202
R13: ffffffff81318a66 R14: 0000000000000000 R15: 0000000000000001
...
Call Trace:
kfree+0xde/0x1bc
assoc_array_cancel_edit+0x1f/0x36
__key_link_end+0x55/0x63
key_reject_and_link+0x124/0x155
keyctl_reject_key+0xb6/0xe0
keyctl_negate_key+0x10/0x12
SyS_keyctl+0x9f/0xe7
do_syscall_64+0x63/0x13a
entry_SYSCALL64_slow_path+0x25/0x25
Fixes: f70e2e0619 ('KEYS: Do preallocation for __key_link()')
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: David Howells <dhowells@redhat.com>
cc: stable@vger.kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The values computed during Diffie-Hellman key exchange are often used
in combination with key derivation functions to create cryptographic
keys. Add a placeholder for a later implementation to configure a
key derivation function that will transform the Diffie-Hellman
result returned by the KEYCTL_DH_COMPUTE command.
[This patch was stripped down from a patch produced by Mat Martineau that
had a bug in the compat code - so for the moment Stephan's patch simply
requires that the placeholder argument must be NULL]
Original-signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: Stephan Mueller <smueller@chronox.de>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: James Morris <james.l.morris@oracle.com>
Here's a set of patches that changes how certificates/keys are determined
to be trusted. That's currently a two-step process:
(1) Up until recently, when an X.509 certificate was parsed - no matter
the source - it was judged against the keys in .system_keyring,
assuming those keys to be trusted if they have KEY_FLAG_TRUSTED set
upon them.
This has just been changed such that any key in the .ima_mok keyring,
if configured, may also be used to judge the trustworthiness of a new
certificate, whether or not the .ima_mok keyring is meant to be
consulted for whatever process is being undertaken.
If a certificate is determined to be trustworthy, KEY_FLAG_TRUSTED
will be set upon a key it is loaded into (if it is loaded into one),
no matter what the key is going to be loaded for.
(2) If an X.509 certificate is loaded into a key, then that key - if
KEY_FLAG_TRUSTED gets set upon it - can be linked into any keyring
with KEY_FLAG_TRUSTED_ONLY set upon it. This was meant to be the
system keyring only, but has been extended to various IMA keyrings.
A user can at will link any key marked KEY_FLAG_TRUSTED into any
keyring marked KEY_FLAG_TRUSTED_ONLY if the relevant permissions masks
permit it.
These patches change that:
(1) Trust becomes a matter of consulting the ring of trusted keys supplied
when the trust is evaluated only.
(2) Every keyring can be supplied with its own manager function to
restrict what may be added to that keyring. This is called whenever a
key is to be linked into the keyring to guard against a key being
created in one keyring and then linked across.
This function is supplied with the keyring and the key type and
payload[*] of the key being linked in for use in its evaluation. It
is permitted to use other data also, such as the contents of other
keyrings such as the system keyrings.
[*] The type and payload are supplied instead of a key because as an
optimisation this function may be called whilst creating a key and
so may reject the proposed key between preparse and allocation.
(3) A default manager function is provided that permits keys to be
restricted to only asymmetric keys that are vouched for by the
contents of the system keyring.
A second manager function is provided that just rejects with EPERM.
(4) A key allocation flag, KEY_ALLOC_BYPASS_RESTRICTION, is made available
so that the kernel can initialise keyrings with keys that form the
root of the trust relationship.
(5) KEY_FLAG_TRUSTED and KEY_FLAG_TRUSTED_ONLY are removed, along with
key_preparsed_payload::trusted.
This change also makes it possible in future for userspace to create a private
set of trusted keys and then to have it sealed by setting a manager function
where the private set is wholly independent of the kernel's trust
relationships.
Further changes in the set involve extracting certain IMA special keyrings
and making them generally global:
(*) .system_keyring is renamed to .builtin_trusted_keys and remains read
only. It carries only keys built in to the kernel. It may be where
UEFI keys should be loaded - though that could better be the new
secondary keyring (see below) or a separate UEFI keyring.
(*) An optional secondary system keyring (called .secondary_trusted_keys)
is added to replace the IMA MOK keyring.
(*) Keys can be added to the secondary keyring by root if the keys can
be vouched for by either ring of system keys.
(*) Module signing and kexec only use .builtin_trusted_keys and do not use
the new secondary keyring.
(*) Config option SYSTEM_TRUSTED_KEYS now depends on ASYMMETRIC_KEY_TYPE as
that's the only type currently permitted on the system keyrings.
(*) A new config option, IMA_KEYRINGS_PERMIT_SIGNED_BY_BUILTIN_OR_SECONDARY,
is provided to allow keys to be added to IMA keyrings, subject to the
restriction that such keys are validly signed by a key already in the
system keyrings.
If this option is enabled, but secondary keyrings aren't, additions to
the IMA keyrings will be restricted to signatures verifiable by keys in
the builtin system keyring only.
Signed-off-by: David Howells <dhowells@redhat.com>
This adds userspace access to Diffie-Hellman computations through a
new keyctl() syscall command to calculate shared secrets or public
keys using input parameters stored in the keyring.
Input key ids are provided in a struct due to the current 5-arg limit
for the keyctl syscall. Only user keys are supported in order to avoid
exposing the content of logon or encrypted keys.
The output is written to the provided buffer, based on the assumption
that the values are only needed in userspace.
Future support for other types of key derivation would involve a new
command, like KEYCTL_ECDH_COMPUTE.
Once Diffie-Hellman support is included in the crypto API, this code
can be converted to use the crypto API to take advantage of possible
hardware acceleration and reduce redundant code.
Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Solved TODO task: big keys saved to shmem file are now stored encrypted.
The encryption key is randomly generated and saved to payload[big_key_data].
Signed-off-by: Kirill Marinushkin <k.marinushkin@gmail.com>
Signed-off-by: David Howells <dhowells@redhat.com>
The payload preparsing routine for user keys makes a copy of the payload
provided by the caller and stashes it in the key_preparsed_payload struct for
->instantiate() or ->update() to use. However, ->update() takes another copy
of this to attach to the keyring. ->update() should be using this directly
and clearing the pointer in the preparse data.
Signed-off-by: David Howells <dhowells@redhat.com>
Remove KEY_FLAG_TRUSTED and KEY_ALLOC_TRUSTED as they're no longer
meaningful. Also we can drop the trusted flag from the preparse structure.
Given this, we no longer need to pass the key flags through to
restrict_link().
Further, we can now get rid of keyring_restrict_trusted_only() also.
Signed-off-by: David Howells <dhowells@redhat.com>
Add a facility whereby proposed new links to be added to a keyring can be
vetted, permitting them to be rejected if necessary. This can be used to
block public keys from which the signature cannot be verified or for which
the signature verification fails. It could also be used to provide
blacklisting.
This affects operations like add_key(), KEYCTL_LINK and KEYCTL_INSTANTIATE.
To this end:
(1) A function pointer is added to the key struct that, if set, points to
the vetting function. This is called as:
int (*restrict_link)(struct key *keyring,
const struct key_type *key_type,
unsigned long key_flags,
const union key_payload *key_payload),
where 'keyring' will be the keyring being added to, key_type and
key_payload will describe the key being added and key_flags[*] can be
AND'ed with KEY_FLAG_TRUSTED.
[*] This parameter will be removed in a later patch when
KEY_FLAG_TRUSTED is removed.
The function should return 0 to allow the link to take place or an
error (typically -ENOKEY, -ENOPKG or -EKEYREJECTED) to reject the
link.
The pointer should not be set directly, but rather should be set
through keyring_alloc().
Note that if called during add_key(), preparse is called before this
method, but a key isn't actually allocated until after this function
is called.
(2) KEY_ALLOC_BYPASS_RESTRICTION is added. This can be passed to
key_create_or_update() or key_instantiate_and_link() to bypass the
restriction check.
(3) KEY_FLAG_TRUSTED_ONLY is removed. The entire contents of a keyring
with this restriction emplaced can be considered 'trustworthy' by
virtue of being in the keyring when that keyring is consulted.
(4) key_alloc() and keyring_alloc() take an extra argument that will be
used to set restrict_link in the new key. This ensures that the
pointer is set before the key is published, thus preventing a window
of unrestrictedness. Normally this argument will be NULL.
(5) As a temporary affair, keyring_restrict_trusted_only() is added. It
should be passed to keyring_alloc() as the extra argument instead of
setting KEY_FLAG_TRUSTED_ONLY on a keyring. This will be replaced in
a later patch with functions that look in the appropriate places for
authoritative keys.
Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
Pull security layer updates from James Morris:
"There are a bunch of fixes to the TPM, IMA, and Keys code, with minor
fixes scattered across the subsystem.
IMA now requires signed policy, and that policy is also now measured
and appraised"
* 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security: (67 commits)
X.509: Make algo identifiers text instead of enum
akcipher: Move the RSA DER encoding check to the crypto layer
crypto: Add hash param to pkcs1pad
sign-file: fix build with CMS support disabled
MAINTAINERS: update tpmdd urls
MODSIGN: linux/string.h should be #included to get memcpy()
certs: Fix misaligned data in extra certificate list
X.509: Handle midnight alternative notation in GeneralizedTime
X.509: Support leap seconds
Handle ISO 8601 leap seconds and encodings of midnight in mktime64()
X.509: Fix leap year handling again
PKCS#7: fix unitialized boolean 'want'
firmware: change kernel read fail to dev_dbg()
KEYS: Use the symbol value for list size, updated by scripts/insert-sys-cert
KEYS: Reserve an extra certificate symbol for inserting without recompiling
modsign: hide openssl output in silent builds
tpm_tis: fix build warning with tpm_tis_resume
ima: require signed IMA policy
ima: measure and appraise the IMA policy itself
ima: load policy using path
...
Pull crypto update from Herbert Xu:
"Here is the crypto update for 4.6:
API:
- Convert remaining crypto_hash users to shash or ahash, also convert
blkcipher/ablkcipher users to skcipher.
- Remove crypto_hash interface.
- Remove crypto_pcomp interface.
- Add crypto engine for async cipher drivers.
- Add akcipher documentation.
- Add skcipher documentation.
Algorithms:
- Rename crypto/crc32 to avoid name clash with lib/crc32.
- Fix bug in keywrap where we zero the wrong pointer.
Drivers:
- Support T5/M5, T7/M7 SPARC CPUs in n2 hwrng driver.
- Add PIC32 hwrng driver.
- Support BCM6368 in bcm63xx hwrng driver.
- Pack structs for 32-bit compat users in qat.
- Use crypto engine in omap-aes.
- Add support for sama5d2x SoCs in atmel-sha.
- Make atmel-sha available again.
- Make sahara hashing available again.
- Make ccp hashing available again.
- Make sha1-mb available again.
- Add support for multiple devices in ccp.
- Improve DMA performance in caam.
- Add hashing support to rockchip"
* 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6: (116 commits)
crypto: qat - remove redundant arbiter configuration
crypto: ux500 - fix checks of error code returned by devm_ioremap_resource()
crypto: atmel - fix checks of error code returned by devm_ioremap_resource()
crypto: qat - Change the definition of icp_qat_uof_regtype
hwrng: exynos - use __maybe_unused to hide pm functions
crypto: ccp - Add abstraction for device-specific calls
crypto: ccp - CCP versioning support
crypto: ccp - Support for multiple CCPs
crypto: ccp - Remove check for x86 family and model
crypto: ccp - memset request context to zero during import
lib/mpi: use "static inline" instead of "extern inline"
lib/mpi: avoid assembler warning
hwrng: bcm63xx - fix non device tree compatibility
crypto: testmgr - allow rfc3686 aes-ctr variants in fips mode.
crypto: qat - The AE id should be less than the maximal AE number
lib/mpi: Endianness fix
crypto: rockchip - add hash support for crypto engine in rk3288
crypto: xts - fix compile errors
crypto: doc - add skcipher API documentation
crypto: doc - update AEAD AD handling
...
The Kconfig currently controlling compilation of this code is:
config BIG_KEYS
bool "Large payload keys"
...meaning that it currently is not being built as a module by anyone.
Lets remove the modular code that is essentially orphaned, so that
when reading the driver there is no doubt it is builtin-only.
Since module_init translates to device_initcall in the non-modular
case, the init ordering remains unchanged with this commit.
We also delete the MODULE_LICENSE tag since all that information
is already contained at the top of the file in the comments.
Cc: James Morris <james.l.morris@oracle.com>
Cc: "Serge E. Hallyn" <serge@hallyn.com>
Cc: keyrings@vger.kernel.org
Cc: linux-security-module@vger.kernel.org
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: David Howells <dhowells@redhat.com>
In my original patch sealing with policy was done with dynamically
allocated buffer that I changed later into an array so the checks in
tpm2-cmd.c became invalid. This patch fixes the issue.
Fixes: 5beb0c435b ("keys, trusted: seal with a TPM2 authorization policy")
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Acked-by: Peter Huewe <peterhuewe@gmx.de>
Add KEY_ALLOC_BUILT_IN to convey that a key should have KEY_FLAG_BUILTIN
set rather than setting it after the fact.
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
KEY_FLAG_KEEP should only be applied to a key if the keyring it is being
linked into has KEY_FLAG_KEEP set.
To this end, partially revert the following patch:
commit 1d6d167c2e
Author: Mimi Zohar <zohar@linux.vnet.ibm.com>
Date: Thu Jan 7 07:46:36 2016 -0500
KEYS: refcount bug fix
to undo the change that made it unconditional (Mimi got it right the first
time).
Without undoing this change, it becomes impossible to delete, revoke or
invalidate keys added to keyrings through __key_instantiate_and_link()
where the keyring has itself been linked to. To test this, run the
following command sequence:
keyctl newring foo @s
keyctl add user a a %:foo
keyctl unlink %user:a %:foo
keyctl clear %:foo
With the commit mentioned above the third and fourth commands fail with
EPERM when they should succeed.
Reported-by: Stephen Gallager <sgallagh@redhat.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
cc: Mimi Zohar <zohar@linux.vnet.ibm.com>
cc: keyrings@vger.kernel.org
cc: stable@vger.kernel.org
Signed-off-by: James Morris <james.l.morris@oracle.com>
This fixes CVE-2016-0728.
If a thread is asked to join as a session keyring the keyring that's already
set as its session, we leak a keyring reference.
This can be tested with the following program:
#include <stddef.h>
#include <stdio.h>
#include <sys/types.h>
#include <keyutils.h>
int main(int argc, const char *argv[])
{
int i = 0;
key_serial_t serial;
serial = keyctl(KEYCTL_JOIN_SESSION_KEYRING,
"leaked-keyring");
if (serial < 0) {
perror("keyctl");
return -1;
}
if (keyctl(KEYCTL_SETPERM, serial,
KEY_POS_ALL | KEY_USR_ALL) < 0) {
perror("keyctl");
return -1;
}
for (i = 0; i < 100; i++) {
serial = keyctl(KEYCTL_JOIN_SESSION_KEYRING,
"leaked-keyring");
if (serial < 0) {
perror("keyctl");
return -1;
}
}
return 0;
}
If, after the program has run, there something like the following line in
/proc/keys:
3f3d898f I--Q--- 100 perm 3f3f0000 0 0 keyring leaked-keyring: empty
with a usage count of 100 * the number of times the program has been run,
then the kernel is malfunctioning. If leaked-keyring has zero usages or
has been garbage collected, then the problem is fixed.
Reported-by: Yevgeny Pats <yevgeny@perception-point.io>
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Don Zickus <dzickus@redhat.com>
Acked-by: Prarit Bhargava <prarit@redhat.com>
Acked-by: Jarod Wilson <jarod@redhat.com>
Signed-off-by: James Morris <james.l.morris@oracle.com>
Pull security subsystem updates from James Morris:
- EVM gains support for loading an x509 cert from the kernel
(EVM_LOAD_X509), into the EVM trusted kernel keyring.
- Smack implements 'file receive' process-based permission checking for
sockets, rather than just depending on inode checks.
- Misc enhancments for TPM & TPM2.
- Cleanups and bugfixes for SELinux, Keys, and IMA.
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security: (41 commits)
selinux: Inode label revalidation performance fix
KEYS: refcount bug fix
ima: ima_write_policy() limit locking
IMA: policy can be updated zero times
selinux: rate-limit netlink message warnings in selinux_nlmsg_perm()
selinux: export validatetrans decisions
gfs2: Invalid security labels of inodes when they go invalid
selinux: Revalidate invalid inode security labels
security: Add hook to invalidate inode security labels
selinux: Add accessor functions for inode->i_security
security: Make inode argument of inode_getsecid non-const
security: Make inode argument of inode_getsecurity non-const
selinux: Remove unused variable in selinux_inode_init_security
keys, trusted: seal with a TPM2 authorization policy
keys, trusted: select hash algorithm for TPM2 chips
keys, trusted: fix: *do not* allow duplicate key options
tpm_ibmvtpm: properly handle interrupted packet receptions
tpm_tis: Tighten IRQ auto-probing
tpm_tis: Refactor the interrupt setup
tpm_tis: Get rid of the duplicate IRQ probing code
...
This patch fixes the key_ref leak, removes the unnecessary KEY_FLAG_KEEP
test before setting the flag, and cleans up the if/then brackets style
introduced in commit:
d3600bc KEYS: prevent keys from being removed from specified keyrings
Reported-by: David Howells <dhowells@redhat.com>
Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
Acked-by: David Howells <dhowells@redhat.com>
TPM2 supports authorization policies, which are essentially
combinational logic statements repsenting the conditions where the data
can be unsealed based on the TPM state. This patch enables to use
authorization policies to seal trusted keys.
Two following new options have been added for trusted keys:
* 'policydigest=': provide an auth policy digest for sealing.
* 'policyhandle=': provide a policy session handle for unsealing.
If 'hash=' option is supplied after 'policydigest=' option, this
will result an error because the state of the option would become
mixed.
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Tested-by: Colin Ian King <colin.king@canonical.com>
Reviewed-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
Acked-by: Peter Huewe <peterhuewe@gmx.de>
Added 'hash=' option for selecting the hash algorithm for add_key()
syscall and documentation for it.
Added entry for sm3-256 to the following tables in order to support
TPM_ALG_SM3_256:
* hash_algo_name
* hash_digest_size
Includes support for the following hash algorithms:
* sha1
* sha256
* sha384
* sha512
* sm3-256
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Tested-by: Colin Ian King <colin.king@canonical.com>
Reviewed-by: James Morris <james.l.morris@oracle.com>
Reviewed-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
Acked-by: Peter Huewe <peterhuewe@gmx.de>
The trusted keys option parsing allows specifying the same option
multiple times. The last option value specified is used.
This is problematic because:
* No gain.
* This makes complicated to specify options that are dependent on other
options.
This patch changes the behavior in a way that option can be specified
only once.
Reported-by: James Morris James Morris <jmorris@namei.org>
Reviewed-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Acked-by: Peter Huewe <peterhuewe@gmx.de>
This fixes CVE-2015-7550.
There's a race between keyctl_read() and keyctl_revoke(). If the revoke
happens between keyctl_read() checking the validity of a key and the key's
semaphore being taken, then the key type read method will see a revoked key.
This causes a problem for the user-defined key type because it assumes in
its read method that there will always be a payload in a non-revoked key
and doesn't check for a NULL pointer.
Fix this by making keyctl_read() check the validity of a key after taking
semaphore instead of before.
I think the bug was introduced with the original keyrings code.
This was discovered by a multithreaded test program generated by syzkaller
(http://github.com/google/syzkaller). Here's a cleaned up version:
#include <sys/types.h>
#include <keyutils.h>
#include <pthread.h>
void *thr0(void *arg)
{
key_serial_t key = (unsigned long)arg;
keyctl_revoke(key);
return 0;
}
void *thr1(void *arg)
{
key_serial_t key = (unsigned long)arg;
char buffer[16];
keyctl_read(key, buffer, 16);
return 0;
}
int main()
{
key_serial_t key = add_key("user", "%", "foo", 3, KEY_SPEC_USER_KEYRING);
pthread_t th[5];
pthread_create(&th[0], 0, thr0, (void *)(unsigned long)key);
pthread_create(&th[1], 0, thr1, (void *)(unsigned long)key);
pthread_create(&th[2], 0, thr0, (void *)(unsigned long)key);
pthread_create(&th[3], 0, thr1, (void *)(unsigned long)key);
pthread_join(th[0], 0);
pthread_join(th[1], 0);
pthread_join(th[2], 0);
pthread_join(th[3], 0);
return 0;
}
Build as:
cc -o keyctl-race keyctl-race.c -lkeyutils -lpthread
Run as:
while keyctl-race; do :; done
as it may need several iterations to crash the kernel. The crash can be
summarised as:
BUG: unable to handle kernel NULL pointer dereference at 0000000000000010
IP: [<ffffffff81279b08>] user_read+0x56/0xa3
...
Call Trace:
[<ffffffff81276aa9>] keyctl_read_key+0xb6/0xd7
[<ffffffff81277815>] SyS_keyctl+0x83/0xe0
[<ffffffff815dbb97>] entry_SYSCALL_64_fastpath+0x12/0x6f
Reported-by: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Tested-by: Dmitry Vyukov <dvyukov@google.com>
Cc: stable@vger.kernel.org
Signed-off-by: James Morris <james.l.morris@oracle.com>
Userspace should not be allowed to remove keys from certain keyrings
(eg. blacklist), though the keys themselves can expire.
This patch defines a new key flag named KEY_FLAG_KEEP to prevent
userspace from being able to unlink, revoke, invalidate or timed
out a key on a keyring. When this flag is set on the keyring, all
keys subsequently added are flagged.
In addition, when this flag is set, the keyring itself can not be
cleared.
Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
Cc: David Howells <dhowells@redhat.com>
If a user key gets negatively instantiated, an error code is cached in the
payload area. A negatively instantiated key may be then be positively
instantiated by updating it with valid data. However, the ->update key
type method must be aware that the error code may be there.
The following may be used to trigger the bug in the user key type:
keyctl request2 user user "" @u
keyctl add user user "a" @u
which manifests itself as:
BUG: unable to handle kernel paging request at 00000000ffffff8a
IP: [<ffffffff810a376f>] __call_rcu.constprop.76+0x1f/0x280 kernel/rcu/tree.c:3046
PGD 7cc30067 PUD 0
Oops: 0002 [#1] SMP
Modules linked in:
CPU: 3 PID: 2644 Comm: a.out Not tainted 4.3.0+ #49
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011
task: ffff88003ddea700 ti: ffff88003dd88000 task.ti: ffff88003dd88000
RIP: 0010:[<ffffffff810a376f>] [<ffffffff810a376f>] __call_rcu.constprop.76+0x1f/0x280
[<ffffffff810a376f>] __call_rcu.constprop.76+0x1f/0x280 kernel/rcu/tree.c:3046
RSP: 0018:ffff88003dd8bdb0 EFLAGS: 00010246
RAX: 00000000ffffff82 RBX: 0000000000000000 RCX: 0000000000000001
RDX: ffffffff81e3fe40 RSI: 0000000000000000 RDI: 00000000ffffff82
RBP: ffff88003dd8bde0 R08: ffff88007d2d2da0 R09: 0000000000000000
R10: 0000000000000000 R11: ffff88003e8073c0 R12: 00000000ffffff82
R13: ffff88003dd8be68 R14: ffff88007d027600 R15: ffff88003ddea700
FS: 0000000000b92880(0063) GS:ffff88007fd00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b
CR2: 00000000ffffff8a CR3: 000000007cc5f000 CR4: 00000000000006e0
Stack:
ffff88003dd8bdf0 ffffffff81160a8a 0000000000000000 00000000ffffff82
ffff88003dd8be68 ffff88007d027600 ffff88003dd8bdf0 ffffffff810a39e5
ffff88003dd8be20 ffffffff812a31ab ffff88007d027600 ffff88007d027620
Call Trace:
[<ffffffff810a39e5>] kfree_call_rcu+0x15/0x20 kernel/rcu/tree.c:3136
[<ffffffff812a31ab>] user_update+0x8b/0xb0 security/keys/user_defined.c:129
[< inline >] __key_update security/keys/key.c:730
[<ffffffff8129e5c1>] key_create_or_update+0x291/0x440 security/keys/key.c:908
[< inline >] SYSC_add_key security/keys/keyctl.c:125
[<ffffffff8129fc21>] SyS_add_key+0x101/0x1e0 security/keys/keyctl.c:60
[<ffffffff8185f617>] entry_SYSCALL_64_fastpath+0x12/0x6a arch/x86/entry/entry_64.S:185
Note the error code (-ENOKEY) in EDX.
A similar bug can be tripped by:
keyctl request2 trusted user "" @u
keyctl add trusted user "a" @u
This should also affect encrypted keys - but that has to be correctly
parameterised or it will fail with EINVAL before getting to the bit that
will crashes.
Reported-by: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
Signed-off-by: James Morris <james.l.morris@oracle.com>
Pull security subsystem update from James Morris:
"This is mostly maintenance updates across the subsystem, with a
notable update for TPM 2.0, and addition of Jarkko Sakkinen as a
maintainer of that"
* 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security: (40 commits)
apparmor: clarify CRYPTO dependency
selinux: Use a kmem_cache for allocation struct file_security_struct
selinux: ioctl_has_perm should be static
selinux: use sprintf return value
selinux: use kstrdup() in security_get_bools()
selinux: use kmemdup in security_sid_to_context_core()
selinux: remove pointless cast in selinux_inode_setsecurity()
selinux: introduce security_context_str_to_sid
selinux: do not check open perm on ftruncate call
selinux: change CONFIG_SECURITY_SELINUX_CHECKREQPROT_VALUE default
KEYS: Merge the type-specific data with the payload data
KEYS: Provide a script to extract a module signature
KEYS: Provide a script to extract the sys cert list from a vmlinux file
keys: Be more consistent in selection of union members used
certs: add .gitignore to stop git nagging about x509_certificate_list
KEYS: use kvfree() in add_key
Smack: limited capability for changing process label
TPM: remove unnecessary little endian conversion
vTPM: support little endian guests
char: Drop owner assignment from i2c_driver
...
