net/tcp: Fix socket lookups with SO_BINDTODEVICE

Similar to 69678bcd4d2d ("udp: fix SO_BINDTODEVICE"), TCP socket lookups
need to fail if dev_match is not true. Currently, a packet to a given port
can match a socket bound to device when it should not. In the VRF case,
this causes the lookup to hit a VRF socket and not a global socket
resulting in a response trying to go through the VRF when it should not.

Fixes: 3fa6f616a7a4d ("net: ipv4: add second dif to inet socket lookups")
Fixes: 4297a0ef08572 ("net: ipv6: add second dif to inet6 socket lookups")
Reported-by: Lou Berger <[e-mail]>
Diagnosed-by: Renato Westphal <[e-mail]>
Tested-by: Renato Westphal <[e-mail]>
Signed-off-by: David Ahern <[e-mail]>
Signed-off-by: David S. Miller <[e-mail]>

net/ipv4/inet_hashtables.c

···
 			bool dev_match = (sk->sk_bound_dev_if == dif ||
 					  sk->sk_bound_dev_if == sdif);
 
-			if (exact_dif && !dev_match)
+			if (!dev_match)
 				return -1;
-			if (sk->sk_bound_dev_if && dev_match)
+			if (sk->sk_bound_dev_if)
 				score += 4;
 		}
 		if (sk->sk_incoming_cpu == raw_smp_processor_id())

net/ipv6/inet6_hashtables.c

···
 			bool dev_match = (sk->sk_bound_dev_if == dif ||
 					  sk->sk_bound_dev_if == sdif);
 
-			if (exact_dif && !dev_match)
+			if (!dev_match)
 				return -1;
-			if (sk->sk_bound_dev_if && dev_match)
+			if (sk->sk_bound_dev_if)
 				score++;
 		}
 		if (sk->sk_incoming_cpu == raw_smp_processor_id())