[NETFILTER]: Fix checks in ip6t_multiport.c

The first patch fixes following bugs in ip6t_multiport.c,

- missing check the size of the preference data.
- IP6T_INV_PROTO should check with not ip->flags but ip->invflags.
Signed-off-by: Yasuyuki KOZAKAI <yasuyuki.kozakai@toshiba.co.jp>
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/ipv6/netfilter/ip6t_multiport.c

@@ -87,9 +87,12 @@ checkentry(const char *tablename,
 {
 	const struct ip6t_multiport *multiinfo = matchinfo;
 
+	if (matchsize != IP6T_ALIGN(sizeof(struct ip6t_multiport)))
+		return 0;
+
 	/* Must specify proto == TCP/UDP, no unknown flags or bad count */
 	return (ip->proto == IPPROTO_TCP || ip->proto == IPPROTO_UDP)
-		&& !(ip->flags & IP6T_INV_PROTO)
+		&& !(ip->invflags & IP6T_INV_PROTO)
 		&& matchsize == IP6T_ALIGN(sizeof(struct ip6t_multiport))
 		&& (multiinfo->flags == IP6T_MULTIPORT_SOURCE
 		    || multiinfo->flags == IP6T_MULTIPORT_DESTINATION