MFC r275703:

Remove PACKET_TAG_IPSEC_IN_DONE mbuf tag lookup and usage of its
security policy. The changed block of code in ip*_ipsec_input() is
called when packet has ESP/AH header. Presence of
PACKET_TAG_IPSEC_IN_DONE mbuf tag in the same time means that
packet was already handled by IPSEC and reinjected in the netisr,
and it has another ESP/AH headers (encrypted twice?).
Since it was already processed by IPSEC code, the AH/ESP headers
was already stripped (and probably outer IP header was stripped too)
and security policy from the tdb_ident was applied to those headers.
It is incorrect to apply this security policy to current headers.

Also make ip_ipsec_input() prototype similar to ip6_ipsec_input().

Obtained from:  Yandex LLC
Sponsored by:   Yandex LLC

TAG:	IPSEC-HEAD
Issue:	#4841

1 files changed, 5 insertions, 21 deletions

diff --git a/sys/netinet6/ip6_ipsec.c b/sys/netinet6/ip6_ipsec.c
index 9e6c13e..9d84349 100644
--- a/sys/netinet6/ip6_ipsec.c
+++ b/sys/netinet6/ip6_ipsec.c
@@ -166,8 +166,6 @@ int
 ip6_ipsec_input(struct mbuf *m, int nxt)
 {
 #ifdef IPSEC
-	struct m_tag *mtag;
-	struct tdb_ident *tdbi;
 	struct secpolicy *sp;
 	int error;
 	/*
@@ -177,21 +175,8 @@ ip6_ipsec_input(struct mbuf *m, int nxt)
 	 */
 	if ((inet6sw[ip6_protox[nxt]].pr_flags & PR_LASTHDR) != 0 &&
 	    ipsec6_in_reject(m, NULL)) {
-
-		/*
-		 * Check if the packet has already had IPsec processing
-		 * done.  If so, then just pass it along.  This tag gets
-		 * set during AH, ESP, etc. input handling, before the
-		 * packet is returned to the ip input queue for delivery.
-		 */
-		mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_DONE, NULL);
-		if (mtag != NULL) {
-			tdbi = (struct tdb_ident *)(mtag + 1);
-			sp = ipsec_getpolicy(tdbi, IPSEC_DIR_INBOUND);
-		} else {
-			sp = ipsec_getpolicybyaddr(m, IPSEC_DIR_INBOUND,
-						   IP_FORWARDING, &error);
-		}
+		sp = ipsec_getpolicybyaddr(m, IPSEC_DIR_INBOUND,
+		    IP_FORWARDING, &error);
 		if (sp != NULL) {
 			/*
 			 * Check security policy against packet attributes.
@@ -202,13 +187,12 @@ ip6_ipsec_input(struct mbuf *m, int nxt)
 			/* XXX error stat??? */
 			error = EINVAL;
 			DPRINTF(("%s: no SP, packet discarded\n", __func__));/*XXX*/
-			return 1;
 		}
-		if (error)
-			return 1;
+		if (error != 0)
+			return (1);
 	}
 #endif /* IPSEC */
-	return 0;
+	return (0);
 }
 
 /*