ipv6: sr: enforce IPv6 packets for seg6local lwt

This patch ensures that the seg6local lightweight tunnel is used solely
with IPv6 routes and processes only IPv6 packets.
Signed-off-by: NDavid Lebrun <david.lebrun@uclouvain.be>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/ipv6/seg6_local.c

@@ -357,6 +357,11 @@ static int seg6_local_input(struct sk_buff *skb)
 	struct seg6_action_desc *desc;
 	struct seg6_local_lwt *slwt;
 
+	if (skb->protocol != htons(ETH_P_IPV6)) {
+		kfree_skb(skb);
+		return -EINVAL;
+	}
+
 	slwt = seg6_local_lwtunnel(orig_dst->lwtstate);
 	desc = slwt->desc;
 
@@ -623,6 +628,9 @@ static int seg6_local_build_state(struct nlattr *nla, unsigned int family,
 	struct seg6_local_lwt *slwt;
 	int err;
 
+	if (family != AF_INET6)
+		return -EINVAL;
+
 	err = nla_parse_nested(tb, SEG6_LOCAL_MAX, nla, seg6_local_policy,
 			       extack);