net/smc: no shutdown in state SMC_LISTEN

commit caa21e19e08d7a1445116a93f7ab4e187ebbbadb upstream.

Invoking shutdown for a socket in state SMC_LISTEN does not make
sense. Nevertheless programs like syzbot fuzzing the kernel may
try to do this. For SMC this means a socket refcounting problem.
This patch makes sure a shutdown call for an SMC socket in state
SMC_LISTEN simply returns with -ENOTCONN.

Signed-off-by: Ursula Braun <ubraun@linux.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/net/smc/af_smc.c b/net/smc/af_smc.c
index 544bab42f925a1eb90ac537a1eee7398e92a7c9f..9c5f447fa3667d9e25c7f570fd44dc4f0b088c13 100644 (file)
--- a/net/smc/af_smc.c
+++ b/net/smc/af_smc.c
@@ -1231,8 +1231,7 @@ static int smc_shutdown(struct socket *sock, int how)
        lock_sock(sk);
 
        rc = -ENOTCONN;
-       if ((sk->sk_state != SMC_LISTEN) &&
-           (sk->sk_state != SMC_ACTIVE) &&
+       if ((sk->sk_state != SMC_ACTIVE) &&
            (sk->sk_state != SMC_PEERCLOSEWAIT1) &&
            (sk->sk_state != SMC_PEERCLOSEWAIT2) &&
            (sk->sk_state != SMC_APPCLOSEWAIT1) &&