diff options
| author | Cong Wang <xiyou.wangcong@gmail.com> | 2017-07-09 13:19:55 -0700 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2017-07-15 11:57:47 +0200 |
| commit | 034e10b4f8348c2c267e491d1e2872023c35f310 (patch) | |
| tree | b5dd445f050778b09e85a3238ae80230b42c0c25 /ipc | |
| parent | 5fd2bba08c17c30d74b26a8b9f6ce67026b254b4 (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.c | 4 |
1 files changed, 3 insertions, 1 deletions
diff --git a/ipc/mqueue.c b/ipc/mqueue.c index 161a1807e6ef..5e24eb0ab5dd 100644 --- a/ipc/mqueue.c +++ b/ipc/mqueue.c @@ -1251,8 +1251,10 @@ 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; |