tcp: md5: release request socket instead of listener

[ Upstream commit 72923555 ]

If tcp_v4_inbound_md5_hash() returns an error, we must release
the refcount on the request socket, not on the listener.

The bug was added for IPv4 only.

Fixes: 079096f1 ("tcp/dccp: install syn_recv requests into ehash table")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

net/ipv4/tcp_ipv4.c

@@ -1597,8 +1597,10 @@ int tcp_v4_rcv(struct sk_buff *skb)
 		struct sock *nsk = NULL;
 
 		sk = req->rsk_listener;
-		if (tcp_v4_inbound_md5_hash(sk, skb))
-			goto discard_and_relse;
+		if (unlikely(tcp_v4_inbound_md5_hash(sk, skb))) {
+			reqsk_put(req);
+			goto discard_it;
+		}
 		if (likely(sk->sk_state == TCP_LISTEN)) {
 			nsk = tcp_check_req(sk, skb, req, false);
 		} else {