linux/security/selinux
Waiman Long f31e799459 selinux: no recursive read_lock of policy_rwlock in security_genfs_sid()
With the introduction of fair queued rwlock, recursive read_lock()
may hang the offending process if there is a write_lock() somewhere
in between.

With recursive read_lock checking enabled, the following error was
reported:

=============================================
[ INFO: possible recursive locking detected ]
3.16.0-rc1 #2 Tainted: G            E
---------------------------------------------
load_policy/708 is trying to acquire lock:
 (policy_rwlock){.+.+..}, at: [<ffffffff8125b32a>]
security_genfs_sid+0x3a/0x170

but task is already holding lock:
 (policy_rwlock){.+.+..}, at: [<ffffffff8125b48c>]
security_fs_use+0x2c/0x110

other info that might help us debug this:
 Possible unsafe locking scenario:

       CPU0
       ----
  lock(policy_rwlock);
  lock(policy_rwlock);

This patch fixes the occurrence of recursive read_lock() of
policy_rwlock by adding a helper function __security_genfs_sid()
which requires caller to take the lock before calling it. The
security_fs_use() was then modified to call the new helper function.

Signed-off-by: Waiman Long <Waiman.Long@hp.com>
Acked-by:  Stephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: Paul Moore <pmoore@redhat.com>
2014-06-23 16:52:55 -04:00
..
include security: Used macros from compiler.h instead of __attribute__((...)) 2014-06-18 16:59:34 -04:00
ss selinux: no recursive read_lock of policy_rwlock in security_genfs_sid() 2014-06-23 16:52:55 -04:00
.gitignore
avc.c selinux: Report permissive mode in avc: denied messages. 2014-05-01 14:56:14 -04:00
exports.c
hooks.c Linux 3.15 2014-06-17 17:30:23 -04:00
Kconfig
Makefile
netif.c net: pass info struct via netdevice notifier 2013-05-28 13:11:01 -07:00
netlabel.c selinux: ensure that the cached NetLabel secattr matches the desired SID 2013-12-04 16:08:17 -05:00
netlink.c
netnode.c selinux: fix problems in netnode when BUG() is compiled out 2013-07-25 13:03:27 -04:00
netport.c
nlmsgtab.c selinux: add SOCK_DIAG_BY_FAMILY to the list of netlink message types 2014-02-05 12:20:48 -05:00
selinuxfs.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security 2014-04-03 09:26:18 -07:00
xfrm.c selinux: add gfp argument to security_xfrm_policy_alloc and fix callers 2014-03-10 08:30:02 +01:00