tipc: close the connection if protocol messages contain errors

When a socket is shutting down, we notify the peer node about the
connection termination by reusing an incoming message if possible.
If the last received message was a connection acknowledgment
message, we reverse this message and set the error code to
TIPC_ERR_NO_PORT and send it to peer.

In tipc_sk_proto_rcv(), we never check for message errors while
processing the connection acknowledgment or probe messages. Thus
this message performs the usual flow control accounting and leaves
the session hanging.

In this commit, we terminate the connection when we receive such
error messages.

Signed-off-by: Parthasarathy Bhuvaragan <parthasarathy.bhuvaragan@ericsson.com>
Reviewed-by: Jon Maloy <jon.maloy@ericsson.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/tipc/socket.c

@@ -866,6 +866,14 @@ static void tipc_sk_proto_rcv(struct tipc_sock *tsk, struct sk_buff *skb,
 	if (!tsk_peer_msg(tsk, hdr))
 		goto exit;
 
+	if (unlikely(msg_errcode(hdr))) {
+		tipc_set_sk_state(sk, TIPC_DISCONNECTING);
+		tipc_node_remove_conn(sock_net(sk), tsk_peer_node(tsk),
+				      tsk_peer_port(tsk));
+		sk->sk_state_change(sk);
+		goto exit;
+	}
+
 	tsk->probe_unacked = false;
 
 	if (mtyp == CONN_PROBE) {