[PATCH 4.17 315/324] net/smc: no shutdown in state SMC_LISTEN

[Greg Kroah-Hartman]

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

------------------

From: Ursula Braun <ubraun@xxxxxxxxxxxxx>

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@xxxxxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 net/smc/af_smc.c |    3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

--- a/net/smc/af_smc.c
+++ b/net/smc/af_smc.c
@@ -1231,8 +1231,7 @@ static int smc_shutdown(struct socket *s
 	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) &&