af_unix: fix shutdown parameter checking

Return -EINVAL rather than 0 given an invalid "mode" parameter.

Signed-off-by: Xi Wang <xi.wang@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 8 insertions, 4 deletions

diff --git a/net/unix/af_unix.c b/net/unix/af_unix.c
index c5ee4ff61364..8a84ab64cafd 100644
--- a/net/unix/af_unix.c
+++ b/net/unix/af_unix.c
@@ -2060,10 +2060,14 @@ static int unix_shutdown(struct socket *sock, int mode)
         struct sock *sk = sock->sk;
         struct sock *other;
 
-        mode = (mode+1)&(RCV_SHUTDOWN|SEND_SHUTDOWN);
-
-        if (!mode)
-                return 0;
+        if (mode < SHUT_RD || mode > SHUT_RDWR)
+                return -EINVAL;
+        /* This maps:
+         * SHUT_RD   (0) -> RCV_SHUTDOWN  (1)
+         * SHUT_WR   (1) -> SEND_SHUTDOWN (2)
+         * SHUT_RDWR (2) -> SHUTDOWN_MASK (3)
+         */
+        ++mode;
 
         unix_state_lock(sk);
         sk->sk_shutdown |= mode;