linux/security/apparmor
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
..
include apparmor: fix suspicious RCU usage warning in policy.c/policy.h 2013-09-30 09:54:01 +10:00
.gitignore AppArmor: remove af_names.h from .gitignore 2012-09-01 08:35:34 -07:00
Kconfig apparmor: add the ability to report a sha1 hash of loaded policy 2013-08-14 11:42:08 -07:00
Makefile apparmor: add the ability to report a sha1 hash of loaded policy 2013-08-14 11:42:08 -07:00
apparmorfs.c apparmor: fix bad lock balance when introspecting policy 2013-10-16 11:54:01 +11:00
audit.c apparmor: fix the audit type table 2013-04-28 00:37:41 -07:00
capability.c apparmor: export set of capabilities supported by the apparmor module 2013-08-14 11:42:07 -07:00
context.c apparmor: change how profile replacement update is done 2013-08-14 11:42:06 -07:00
crypto.c apparmor: Use shash crypto API interface for profile hashes 2013-09-30 09:53:59 +10:00
domain.c apparmor: allow setting any profile into the unconfined state 2013-08-14 11:42:07 -07:00
file.c new helper: file_inode(file) 2013-02-22 23:31:31 -05:00
ipc.c apparmor: add utility function to get an arbitrary tasks profile. 2013-04-28 00:35:53 -07:00
lib.c apparmor: remove minimum size check for vmalloc() 2013-08-14 11:42:05 -07:00
lsm.c Merge branch 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security 2013-09-07 14:34:07 -07:00
match.c apparmor: reserve and mask off the top 8 bits of the base field 2013-04-28 00:37:32 -07:00
path.c apparmor: fix error code to failure message mapping for name lookup 2013-04-28 00:35:40 -07:00
policy.c apparmor: fix memleak of the profile hash 2013-10-16 11:53:59 +11:00
policy_unpack.c apparmor: add the ability to report a sha1 hash of loaded policy 2013-08-14 11:42:08 -07:00
procattr.c apparmor: add interface files for profiles and namespaces 2013-08-14 11:42:07 -07:00
resource.c apparmor: relax the restrictions on setting rlimits 2013-04-28 00:36:46 -07:00
sid.c AppArmor: core policy routines 2010-08-02 15:38:37 +10:00