linux/security
John Johansen ed2c7da3a4 apparmor: fix bad lock balance when introspecting policy
BugLink: http://bugs.launchpad.net/bugs/1235977

The profile introspection seq file has a locking bug when policy is viewed
from a virtual root (task in a policy namespace), introspection from the
real root is not affected.

The test for root
    while (parent) {
is correct for the real root, but incorrect for tasks in a policy namespace.
This allows the task to walk backup the policy tree past its virtual root
causing it to be unlocked before the virtual root should be in the p_stop
fn.

This results in the following lockdep back trace:
[   78.479744] [ BUG: bad unlock balance detected! ]
[   78.479792] 3.11.0-11-generic #17 Not tainted
[   78.479838] -------------------------------------
[   78.479885] grep/2223 is trying to release lock (&ns->lock) at:
[   78.479952] [<ffffffff817bf3be>] mutex_unlock+0xe/0x10
[   78.480002] but there are no more locks to release!
[   78.480037]
[   78.480037] other info that might help us debug this:
[   78.480037] 1 lock held by grep/2223:
[   78.480037]  #0:  (&p->lock){+.+.+.}, at: [<ffffffff812111bd>] seq_read+0x3d/0x3d0
[   78.480037]
[   78.480037] stack backtrace:
[   78.480037] CPU: 0 PID: 2223 Comm: grep Not tainted 3.11.0-11-generic #17
[   78.480037] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[   78.480037]  ffffffff817bf3be ffff880007763d60 ffffffff817b97ef ffff8800189d2190
[   78.480037]  ffff880007763d88 ffffffff810e1c6e ffff88001f044730 ffff8800189d2190
[   78.480037]  ffffffff817bf3be ffff880007763e00 ffffffff810e5bd6 0000000724fe56b7
[   78.480037] Call Trace:
[   78.480037]  [<ffffffff817bf3be>] ? mutex_unlock+0xe/0x10
[   78.480037]  [<ffffffff817b97ef>] dump_stack+0x54/0x74
[   78.480037]  [<ffffffff810e1c6e>] print_unlock_imbalance_bug+0xee/0x100
[   78.480037]  [<ffffffff817bf3be>] ? mutex_unlock+0xe/0x10
[   78.480037]  [<ffffffff810e5bd6>] lock_release_non_nested+0x226/0x300
[   78.480037]  [<ffffffff817bf2fe>] ? __mutex_unlock_slowpath+0xce/0x180
[   78.480037]  [<ffffffff817bf3be>] ? mutex_unlock+0xe/0x10
[   78.480037]  [<ffffffff810e5d5c>] lock_release+0xac/0x310
[   78.480037]  [<ffffffff817bf2b3>] __mutex_unlock_slowpath+0x83/0x180
[   78.480037]  [<ffffffff817bf3be>] mutex_unlock+0xe/0x10
[   78.480037]  [<ffffffff81376c91>] p_stop+0x51/0x90
[   78.480037]  [<ffffffff81211408>] seq_read+0x288/0x3d0
[   78.480037]  [<ffffffff811e9d9e>] vfs_read+0x9e/0x170
[   78.480037]  [<ffffffff811ea8cc>] SyS_read+0x4c/0xa0
[   78.480037]  [<ffffffff817ccc9d>] system_call_fastpath+0x1a/0x1f

Signed-off-by: John Johansen <john.johansen@canonical.com>
Signed-off-by: James Morris <james.l.morris@oracle.com>
2013-10-16 11:54:01 +11:00
..
apparmor apparmor: fix bad lock balance when introspecting policy 2013-10-16 11:54:01 +11:00
integrity xattr: Constify ->name member of "struct xattr". 2013-07-25 19:30:03 +10:00
keys aio: don't include aio.h in sched.h 2013-05-07 20:16:25 -07:00
selinux selinux: remove 'flags' parameter from avc_audit() 2013-10-04 14:13:25 -07:00
smack Merge branch 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security 2013-09-07 14:34:07 -07:00
tomoyo Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2013-05-01 17:51:54 -07:00
yama yama: Better permission check for ptraceme 2013-03-26 13:17:58 -07:00
capability.c xattr: Constify ->name member of "struct xattr". 2013-07-25 19:30:03 +10:00
commoncap.c capabilities: allow nice if we are privileged 2013-08-30 23:44:09 -07:00
device_cgroup.c cgroup: make css_for_each_descendant() and friends include the origin css in the iteration 2013-08-08 20:11:27 -04:00
inode.c securityfs: fix object creation races 2012-01-10 10:20:35 -05:00
Kconfig KEYS: Move the key config into security/keys/Kconfig 2012-05-11 10:56:56 +01:00
lsm_audit.c LSM: BUILD_BUG_ON if the common_audit_data union ever grows 2012-04-09 12:23:03 -04:00
Makefile security: Yama LSM 2012-02-10 09:18:52 +11:00
min_addr.c mmap_min_addr check CAP_SYS_RAWIO only for write 2010-04-23 08:56:31 +10:00
security.c xattr: Constify ->name member of "struct xattr". 2013-07-25 19:30:03 +10:00