diff options
| author | Cong Wang <xiyou.wangcong@gmail.com> | 2017-07-09 13:19:55 -0700 |
|---|---|---|
| committer | Sasha Levin <alexander.levin@verizon.com> | 2017-07-31 13:37:53 -0400 |
| commit | 89e4078c6ea15ea65e3d5aa3d72e7913b7b500da (patch) | |
| tree | 18957527a2a8c67df22cb8b1c8b94f84c834cb8a /ipc | |
| parent | 061f921acebc96f2ac28302bbcd2df45c13e1636 (diff) | |
mqueue: fix a use-after-free in sys_mq_notify()
[ Upstream commit f991af3daabaecff34684fd51fac80319d1baad1 ]
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>
Cc: stable@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
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 c3fc5c2b63f3..e4e8b6080b33 100644 --- a/ipc/mqueue.c +++ b/ipc/mqueue.c @@ -1239,8 +1239,10 @@ 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; |