Fix handling of scoped IPv6 addresses in IPSec code.

* in ipsec_encap() embed scope zone ids into link-local addresses
  in the new IPv6 header, this helps ip6_output() disambiguate the
  scope;
* teach key_ismyaddr6() use in6_localip(). in6_localip() is less
  strict than key_sockaddrcmp(). It doesn't compare all fileds of
  struct sockaddr_in6, but it is faster and it should be safe,
  because all SA's data was checked for correctness. Also, since
  IPv6 link-local addresses in the &V_in6_ifaddrhead are stored in
  kernel-internal form, we need to embed scope zone id from SA into
  the address before calling in6_localip.
* in ipsec_common_input() take scope zone id embedded in the address
  and use it to initialize sin6_scope_id, then use this sockaddr
  structure to lookup SA, because we keep addresses in the SADB without
  embedded scope zone id.

Differential Revision:	https://reviews.freebsd.org/D2304
Reviewed by:	gnn
Sponsored by:	Yandex LLC

1 files changed, 7 insertions, 0 deletions

diff --git a/sys/netipsec/ipsec_output.c b/sys/netipsec/ipsec_output.c
index 2c06c86..691e684 100644
--- a/sys/netipsec/ipsec_output.c
+++ b/sys/netipsec/ipsec_output.c
@@ -503,7 +503,14 @@ ipsec_encap(struct mbuf **mp, struct secasindex *saidx)
 		ip6->ip6_hlim = V_ip6_defhlim;
 		ip6->ip6_nxt = proto;
 		ip6->ip6_dst = saidx->dst.sin6.sin6_addr;
+		/* For link-local address embed scope zone id */
+		if (IN6_IS_SCOPE_LINKLOCAL(&ip6->ip6_dst))
+			ip6->ip6_dst.s6_addr16[1] =
+			    htons(saidx->dst.sin6.sin6_scope_id & 0xffff);
 		ip6->ip6_src = saidx->src.sin6.sin6_addr;
+		if (IN6_IS_SCOPE_LINKLOCAL(&ip6->ip6_src))
+			ip6->ip6_src.s6_addr16[1] =
+			    htons(saidx->src.sin6.sin6_scope_id & 0xffff);
 		ip6->ip6_plen = htons((*mp)->m_pkthdr.len - sizeof(*ip6));
 		ip_ecn_ingress(V_ip6_ipsec_ecn, &proto, &itos);
 		ip6->ip6_flow |= htonl((uint32_t)proto << 20);