ipc,shm: correct error return value in shmctl (SHM_UNLOCK)
authorJesper Nilsson <jesper.nilsson@axis.com>
Thu, 21 Nov 2013 22:32:08 +0000 (14:32 -0800)
committerLinus Torvalds <torvalds@linux-foundation.org>
Fri, 22 Nov 2013 00:42:28 +0000 (16:42 -0800)
commit3a72660b07d86d60457ca32080b1ce8c2b628ee2
treeedc6f42a551b165943c4590389482c70d6f6639f
parentb7a9f420ed737cb7cd4075ba06ac1a6f0da9f878
ipc,shm: correct error return value in shmctl (SHM_UNLOCK)

Commit 2caacaa82a51 ("ipc,shm: shorten critical region for shmctl")
restructured the ipc shm to shorten critical region, but introduced a
path where the return value could be -EPERM, even if the operation
actually was performed.

Before the commit, the err return value was reset by the return value
from security_shm_shmctl() after the if (!ns_capable(...)) statement.

Now, we still exit the if statement with err set to -EPERM, and in the
case of SHM_UNLOCK, it is not reset at all, and used as the return value
from shmctl.

To fix this, we only set err when errors occur, leaving the fallthrough
case alone.

Signed-off-by: Jesper Nilsson <jesper.nilsson@axis.com>
Cc: Davidlohr Bueso <davidlohr@hp.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Michel Lespinasse <walken@google.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: <stable@vger.kernel.org> [3.12.x]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
ipc/shm.c