MFC r275702:

Remove check for presence of PACKET_TAG_IPSEC_PENDING_TDB and
PACKET_TAG_IPSEC_OUT_CRYPTO_NEEDED mbuf tags. They aren't used in FreeBSD.

Instead check presence of PACKET_TAG_IPSEC_OUT_DONE mbuf tag. If it
is found, bypass security policy lookup as described in the comment.

PACKET_TAG_IPSEC_OUT_DONE tag added to mbuf when IPSEC code finishes
ESP/AH processing. Since it was already finished, this means the security
policy placed in the tdb_ident was already checked. And there is no reason
to check it again here.

Obtained from:  Yandex LLC
Sponsored by:   Yandex LLC

TAG:	IPSEC-HEAD
Issue:	#4841

1 files changed, 6 insertions, 49 deletions

diff --git a/sys/netinet/ip_ipsec.c b/sys/netinet/ip_ipsec.c
index 4d428c1..cd3f0e6 100644
--- a/sys/netinet/ip_ipsec.c
+++ b/sys/netinet/ip_ipsec.c
@@ -216,9 +216,7 @@ ip_ipsec_mtu(struct mbuf *m, int mtu)
 int
 ip_ipsec_output(struct mbuf **m, struct inpcb *inp, int *flags, int *error)
 {
-	struct secpolicy *sp = NULL;
-	struct tdb_ident *tdbi;
-	struct m_tag *mtag;
+	struct secpolicy *sp;
 	/*
 	 * Check the security policy (SP) for the packet and, if
 	 * required, do IPsec-related processing.  There are two
@@ -228,17 +226,11 @@ ip_ipsec_output(struct mbuf **m, struct inpcb *inp, int *flags, int *error)
 	 * AH, ESP, etc. processing), there will be a tag to bypass
 	 * the lookup and related policy checking.
 	 */
-	mtag = m_tag_find(*m, PACKET_TAG_IPSEC_PENDING_TDB, NULL);
-	if (mtag != NULL) {
-		tdbi = (struct tdb_ident *)(mtag + 1);
-		sp = ipsec_getpolicy(tdbi, IPSEC_DIR_OUTBOUND);
-		if (sp == NULL)
-			*error = -EINVAL;	/* force silent drop */
-		m_tag_delete(*m, mtag);
-	} else {
-		sp = ipsec4_checkpolicy(*m, IPSEC_DIR_OUTBOUND, *flags,
-					error, inp);
+	if (m_tag_find(*m, PACKET_TAG_IPSEC_OUT_DONE, NULL) != NULL) {
+		*error = 0;
+		return (0);
 	}
+	sp = ipsec4_checkpolicy(*m, IPSEC_DIR_OUTBOUND, *flags, error, inp);
 	/*
 	 * There are four return cases:
 	 *    sp != NULL	 	    apply IPsec policy
@@ -247,40 +239,6 @@ ip_ipsec_output(struct mbuf **m, struct inpcb *inp, int *flags, int *error)
 	 *    sp == NULL, error != 0	    discard packet, report error
 	 */
 	if (sp != NULL) {
-		/* Loop detection, check if ipsec processing already done */
-		KASSERT(sp->req != NULL, ("ip_output: no ipsec request"));
-		for (mtag = m_tag_first(*m); mtag != NULL;
-		     mtag = m_tag_next(*m, mtag)) {
-			if (mtag->m_tag_cookie != MTAG_ABI_COMPAT)
-				continue;
-			if (mtag->m_tag_id != PACKET_TAG_IPSEC_OUT_DONE &&
-			    mtag->m_tag_id != PACKET_TAG_IPSEC_OUT_CRYPTO_NEEDED)
-				continue;
-			/*
-			 * Check if policy has an SA associated with it.
-			 * This can happen when an SP has yet to acquire
-			 * an SA; e.g. on first reference.  If it occurs,
-			 * then we let ipsec4_process_packet do its thing.
-			 */
-			if (sp->req->sav == NULL)
-				break;
-			tdbi = (struct tdb_ident *)(mtag + 1);
-			if (tdbi->spi == sp->req->sav->spi &&
-			    tdbi->proto == sp->req->sav->sah->saidx.proto &&
-			    bcmp(&tdbi->dst, &sp->req->sav->sah->saidx.dst,
-				 sizeof (union sockaddr_union)) == 0) {
-				/*
-				 * No IPsec processing is needed, free
-				 * reference to SP.
-				 *
-				 * NB: null pointer to avoid free at
-				 *     done: below.
-				 */
-				KEY_FREESP(&sp), sp = NULL;
-				goto done;
-			}
-		}
-
 		/*
 		 * Do delayed checksums now because we send before
 		 * this is done in the normal processing path.
@@ -331,9 +289,8 @@ ip_ipsec_output(struct mbuf **m, struct inpcb *inp, int *flags, int *error)
 			if (*error == -EINVAL)
 				*error = 0;
 			goto bad;
-		} else {
-			/* No IPsec processing for this packet. */
 		}
+		/* No IPsec processing for this packet. */
 	}
 done:
 	if (sp != NULL)