summaryrefslogtreecommitdiff
path: root/ipc
diff options
context:
space:
mode:
authorCong Wang <xiyou.wangcong@gmail.com>2017-07-09 13:19:55 -0700
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2017-07-15 12:16:10 +0200
commite6952841ade0f937750c7748a812cb403bd744b0 (patch)
tree6285620a3d1b7d676e9ce367a6d9cfac05a30045 /ipc
parentc48f76d680ad9ad443290ce0f1e8f92db6986bf5 (diff)
mqueue: fix a use-after-free in sys_mq_notify()
commit f991af3daabaecff34684fd51fac80319d1baad1 upstream. The retry logic for netlink_attachskb() inside sys_mq_notify() is nasty and vulnerable: 1) The sock refcnt is already released when retry is needed 2) The fd is controllable by user-space because we already release the file refcnt so we when retry but the fd has been just closed by user-space during this small window, we end up calling netlink_detachskb() on the error path which releases the sock again, later when the user-space closes this socket a use-after-free could be triggered. Setting 'sock' to NULL here should be sufficient to fix it. Reported-by: GeneBlue <geneblue.mail@gmail.com> Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Manfred Spraul <manfred@colorfullife.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'ipc')
-rw-r--r--ipc/mqueue.c4
1 files changed, 3 insertions, 1 deletions
diff --git a/ipc/mqueue.c b/ipc/mqueue.c
index 8cbd6e6894d5..28a142f1be36 100644
--- a/ipc/mqueue.c
+++ b/ipc/mqueue.c
@@ -1249,8 +1249,10 @@ retry:
timeo = MAX_SCHEDULE_TIMEOUT;
ret = netlink_attachskb(sock, nc, &timeo, NULL);
- if (ret == 1)
+ if (ret == 1) {
+ sock = NULL;
goto retry;
+ }
if (ret) {
sock = NULL;
nc = NULL;