af_unix: fix struct pid memory leak

Orabug: 23330931

[ Upstream commit fa0dc04df259ba2df3ce1920e9690c7842f8fa4b ]

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@google.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Rainer Weikusat <rweikusat@mobileactivedefense.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
(cherry picked from commit 8d988538da0c17711c0de0a53fc38cef49e3ed1b)

Signed-off-by: Dan Duval <dan.duval@oracle.com>

diff --git a/net/unix/af_unix.c b/net/unix/af_unix.c
index 05dbffdea76feda4606d9dbc98fdbfd2d02b74f2..bed68be1919798d35e7daad1eae019af5564cd39 100644 (file)
--- a/net/unix/af_unix.c
+++ b/net/unix/af_unix.c
@@ -2139,6 +2139,7 @@ again:
                        if (signal_pending(current)
                            ||  mutex_lock_interruptible(&u->readlock)) {
                                err = sock_intr_errno(timeo);
+                               scm_destroy(&scm);
                                goto out;
                        }