[PATCH 3.13.y-ckt 118/138] af_unix: fix struct pid memory leak

From: Kamal Mostafa
Date: Wed Mar 09 2016 - 18:20:42 EST

3.13.11-ckt36 -stable review patch. If anyone has any objections, please let me know.


From: Eric Dumazet <edumazet@xxxxxxxxxx>

commit fa0dc04df259ba2df3ce1920e9690c7842f8fa4b upstream.

Dmitry reported a struct pid leak detected by a syzkaller program.

Bug happens in unix_stream_recvmsg() when we break the loop when a
signal is pending, without properly releasing scm.

Fixes: b3ca9b02b007 ("net: fix multithreaded signal handling in unix recv routines")
Reported-by: Dmitry Vyukov <dvyukov@xxxxxxxxxx>
Signed-off-by: Eric Dumazet <edumazet@xxxxxxxxxx>
Cc: Rainer Weikusat <rweikusat@xxxxxxxxxxxxxxxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
[ luis: backported to 3.16:
- use siocb->scm instead of &scm ]
Signed-off-by: Luis Henriques <luis.henriques@xxxxxxxxxxxxx>

Signed-off-by: Kamal Mostafa <kamal@xxxxxxxxxxxxx>
net/unix/af_unix.c | 1 +
1 file changed, 1 insertion(+)

diff --git a/net/unix/af_unix.c b/net/unix/af_unix.c
index e6b0213..496ce9c 100644
--- a/net/unix/af_unix.c
+++ b/net/unix/af_unix.c
@@ -2147,6 +2147,7 @@ again:

if (signal_pending(current)) {
err = sock_intr_errno(timeo);
+ scm_destroy(siocb->scm);
goto out;