tipc: improve address sanity check in tipc_connect()

The address given to tipc_connect() is not completely sanity checked,
under the assumption that this will be done later in the function
__tipc_sendmsg() when the address is used there.

However, the latter functon will in the next commits serve as caller
to several other send functions, so we want to move the corresponding
sanity check there to the beginning of that function, before we possibly
need to grab the address stored by tipc_connect(). We must therefore
be able to trust that this address already has been thoroughly checked.

We do this in this commit.
Signed-off-by: Jon Maloy <jon.maloy@ericsson.com>
Acked-by: Ying Xue <ying.xue@windriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/tipc/socket.c

@@ -1911,28 +1911,27 @@ static int tipc_connect(struct socket *sock, struct sockaddr *dest,
 	int previous;
 	int res = 0;
 
+	if (destlen != sizeof(struct sockaddr_tipc))
+		return -EINVAL;
+
 	lock_sock(sk);
 
-	/* DGRAM/RDM connect(), just save the destaddr */
-	if (tipc_sk_type_connectionless(sk)) {
-		if (dst->family == AF_UNSPEC) {
-			memset(&tsk->peer, 0, sizeof(struct sockaddr_tipc));
-		} else if (destlen != sizeof(struct sockaddr_tipc)) {
+	if (dst->family == AF_UNSPEC) {
+		memset(&tsk->peer, 0, sizeof(struct sockaddr_tipc));
+		if (!tipc_sk_type_connectionless(sk))
 			res = -EINVAL;
-		} else {
-			memcpy(&tsk->peer, dest, destlen);
-		}
 		goto exit;
+	} else if (dst->family != AF_TIPC) {
+		res = -EINVAL;
 	}
-
-	/*
-	 * Reject connection attempt using multicast address
-	 *
-	 * Note: send_msg() validates the rest of the address fields,
-	 *       so there's no need to do it here
-	 */
-	if (dst->addrtype == TIPC_ADDR_MCAST) {
+	if (dst->addrtype != TIPC_ADDR_ID && dst->addrtype != TIPC_ADDR_NAME)
 		res = -EINVAL;
+	if (res)
+		goto exit;
+
+	/* DGRAM/RDM connect(), just save the destaddr */
+	if (tipc_sk_type_connectionless(sk)) {
+		memcpy(&tsk->peer, dest, destlen);
 		goto exit;
 	}