unix: If we happen to find peer NULL when diag dumping, write zero.

Otherwise we leave uninitialized kernel memory in there.
Reported-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/unix/diag.c

@@ -86,8 +86,7 @@ static int sk_diag_dump_icons(struct sock *sk, struct sk_buff *nlskb)
 			 */
 			unix_state_lock_nested(req);
 			peer = unix_sk(req)->peer;
-			if (peer)
-				buf[i++] = sock_i_ino(peer);
+			buf[i++] = (peer ? sock_i_ino(peer) : 0);
 			unix_state_unlock(req);
 		}
 		spin_unlock(&sk->sk_receive_queue.lock);