tipc: compare remote and local protocols in tipc_udp_enable()

[ Upstream commit fb83ed49 ]

When TIPC_NLA_UDP_REMOTE is an IPv6 mcast address but
TIPC_NLA_UDP_LOCAL is an IPv4 address, a NULL-ptr deref is triggered
as the UDP tunnel sock is initialized to IPv4 or IPv6 sock merely
based on the protocol in local address.

We should just error out when the remote address and local address
have different protocols.

Reported-by: syzbot+eb4da3a20fad2e52555d@syzkaller.appspotmail.com
Cc: Ying Xue <ying.xue@windriver.com>
Cc: Jon Maloy <jon.maloy@ericsson.com>
Signed-off-by: NCong Wang <xiyou.wangcong@gmail.com>
Acked-by: NJon Maloy <jon.maloy@ericsson.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: NYang Yingliang <yangyingliang@huawei.com>

net/tipc/udp_media.c

@@ -680,6 +680,11 @@ static int tipc_udp_enable(struct net *net, struct tipc_bearer *b,
 	if (err)
 		goto err;
 
+	if (remote.proto != local.proto) {
+		err = -EINVAL;
+		goto err;
+	}
+
 	/* Autoconfigure own node identity if needed */
 	if (!tipc_own_id(net)) {
 		memcpy(node_id, local.ipv6.in6_u.u6_addr8, 16);