WSL2-Linux-Kernel/security
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
..
apparmor nick kvfree() from apparmor 2014-05-06 14:02:53 -04:00
integrity Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2014-04-12 14:49:50 -07:00
keys 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
selinux selinux: no recursive read_lock of policy_rwlock in security_genfs_sid() 2014-06-23 16:52:55 -04:00
smack Linux 3.13 2014-03-07 11:41:32 -05:00
tomoyo get rid of pointless checks for NULL ->i_op 2014-04-01 23:19:16 -04:00
yama
Kconfig security: select correct default LSM_MMAP_MIN_ADDR on arm on arm64 2014-02-05 14:59:14 +00:00
Makefile security: cleanup Makefiles to use standard syntax for specifying sub-directories 2014-02-17 11:08:04 +11:00
capability.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
commoncap.c
device_cgroup.c device_cgroup: check if exception removal is allowed 2014-05-05 11:20:12 -04:00
inode.c
lsm_audit.c audit: anchor all pid references in the initial pid namespace 2014-03-20 10:11:55 -04:00
min_addr.c
security.c vfs: add cross-rename 2014-04-01 17:08:43 +02:00