This is a note to let you know that I've just added the patch titled
ipc,shm: correct error return value in shmctl (SHM_UNLOCK)
to the 3.12-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
ipc-shm-correct-error-return-value-in-shmctl-shm_unlock.patch
and it can be found in the queue-3.12 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 3a72660b07d86d60457ca32080b1ce8c2b628ee2 Mon Sep 17 00:00:00 2001
From: Jesper Nilsson <jesper.nilsson@xxxxxxxx>
Date: Thu, 21 Nov 2013 14:32:08 -0800
Subject: ipc,shm: correct error return value in shmctl (SHM_UNLOCK)
From: Jesper Nilsson <jesper.nilsson@xxxxxxxx>
commit 3a72660b07d86d60457ca32080b1ce8c2b628ee2 upstream.
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@xxxxxxxx>
Cc: Davidlohr Bueso <davidlohr@xxxxxx>
Cc: Rik van Riel <riel@xxxxxxxxxx>
Cc: Michel Lespinasse <walken@xxxxxxxxxx>
Cc: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
ipc/shm.c | 9 ++++++---
1 file changed, 6 insertions(+), 3 deletions(-)
--- a/ipc/shm.c
+++ b/ipc/shm.c
@@ -974,12 +974,15 @@ SYSCALL_DEFINE3(shmctl, int, shmid, int,
ipc_lock_object(&shp->shm_perm);
if (!ns_capable(ns->user_ns, CAP_IPC_LOCK)) {
kuid_t euid = current_euid();
- err = -EPERM;
if (!uid_eq(euid, shp->shm_perm.uid) &&
- !uid_eq(euid, shp->shm_perm.cuid))
+ !uid_eq(euid, shp->shm_perm.cuid)) {
+ err = -EPERM;
goto out_unlock0;
- if (cmd == SHM_LOCK && !rlimit(RLIMIT_MEMLOCK))
+ }
+ if (cmd == SHM_LOCK && !rlimit(RLIMIT_MEMLOCK)) {
+ err = -EPERM;
goto out_unlock0;
+ }
}
shm_file = shp->shm_file;
Patches currently in stable-queue which might be from jesper.nilsson@xxxxxxxx are
queue-3.12/ipc-shm-correct-error-return-value-in-shmctl-shm_unlock.patch
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