Enforce messages after IKE_SA_INIT exchange to contain only

encrypted payloads.  Also increment message id only for valid
messages.

From Tobias Heider
ok sthen@

3 files changed, 25 insertions, 13 deletions

diff --git a/sbin/iked/iked.h b/sbin/iked/iked.h
index 9e2972c6ebf..ce55aec2aa5 100644
--- a/sbin/iked/iked.h
+++ b/sbin/iked/iked.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: iked.h,v 1.119 2018/08/06 06:30:06 mestre Exp $	*/
+/*	$OpenBSD: iked.h,v 1.120 2019/05/10 15:02:17 patrick Exp $	*/
 
 /*
  * Copyright (c) 2010-2013 Reyk Floeter <reyk@openbsd.org>
@@ -366,6 +366,7 @@ struct iked_sa {
 	struct iked_sahdr		 sa_hdr;
 	uint32_t			 sa_msgid;	/* Last request rcvd */
 	int				 sa_msgid_set;	/* msgid initialized */
+	uint32_t			 sa_msgid_current;	/* Current requested rcvd */
 	uint32_t			 sa_reqid;	/* Next request sent */
 
 	int				 sa_type;
@@ -491,6 +492,7 @@ struct iked_message {
 	int			 msg_fd;
 	int			 msg_response;
 	int			 msg_responded;
+	int			 msg_valid;
 	int			 msg_natt;
 	int			 msg_natt_rcvd;
 	int			 msg_error;
diff --git a/sbin/iked/ikev2.c b/sbin/iked/ikev2.c
index c928267a682..f1573417be1 100644
--- a/sbin/iked/ikev2.c
+++ b/sbin/iked/ikev2.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: ikev2.c,v 1.168 2019/02/27 06:33:56 sthen Exp $	*/
+/*	$OpenBSD: ikev2.c,v 1.169 2019/05/10 15:02:17 patrick Exp $	*/
 
 /*
  * Copyright (c) 2010-2013 Reyk Floeter <reyk@openbsd.org>
@@ -438,6 +438,10 @@ ikev2_recv(struct iked *env, struct iked_message *msg)
 	if (hdr->ike_exchange == IKEV2_EXCHANGE_INFORMATIONAL)
 		flag = IKED_REQ_INF;
 
+	if (hdr->ike_exchange != IKEV2_EXCHANGE_IKE_SA_INIT &&
+	    hdr->ike_nextpayload != IKEV2_PAYLOAD_SK)
+		return;
+
 	if (msg->msg_response) {
 		if (msg->msg_msgid > sa->sa_reqid)
 			return;
@@ -497,15 +501,7 @@ ikev2_recv(struct iked *env, struct iked_message *msg)
 			 */
 			return;
 		}
-		/*
-		 * If it's a new request, make sure to update the peer's
-		 * message ID and dispose of all previous responses.
-		 * We need to set sa_msgid_set in order to distinguish between
-		 * "last msgid was 0" and "msgid not set yet".
-		 */
-		sa->sa_msgid = msg->msg_msgid;
-		sa->sa_msgid_set = 1;
-		ikev2_msg_prevail(env, &sa->sa_responses, msg);
+		sa->sa_msgid_current = msg->msg_msgid;
 	}
 
 	if (sa_address(sa, &sa->sa_peer, &msg->msg_peer) == -1 ||
@@ -524,6 +520,18 @@ done:
 	else
 		ikev2_resp_recv(env, msg, hdr);
 
+	if (sa != NULL && !msg->msg_response && msg->msg_valid) {
+		/*
+		 * If it's a valid request, make sure to update the peer's
+		 * message ID and dispose of all previous responses.
+		 * We need to set sa_msgid_set in order to distinguish between
+		 * "last msgid was 0" and "msgid not set yet".
+		 */
+		sa->sa_msgid = sa->sa_msgid_current;
+		sa->sa_msgid_set = 1;
+		ikev2_msg_prevail(env, &sa->sa_responses, msg);
+	}
+
 	if (sa != NULL && sa->sa_state == IKEV2_STATE_CLOSED) {
 		log_debug("%s: closing SA", __func__);
 		sa_free(env, sa);
@@ -2283,6 +2291,8 @@ ikev2_resp_recv(struct iked *env, struct iked_message *msg,
 	if ((sa = msg->msg_sa) == NULL)
 		return;
 
+	msg->msg_valid = 1;
+
 	if (msg->msg_natt && sa->sa_natt == 0) {
 		log_debug("%s: NAT-T message received, updated SA", __func__);
 		sa->sa_natt = 1;
diff --git a/sbin/iked/ikev2_msg.c b/sbin/iked/ikev2_msg.c
index e94d699e6cf..b559990bec4 100644
--- a/sbin/iked/ikev2_msg.c
+++ b/sbin/iked/ikev2_msg.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: ikev2_msg.c,v 1.53 2017/11/27 18:39:35 patrick Exp $	*/
+/*	$OpenBSD: ikev2_msg.c,v 1.54 2019/05/10 15:02:17 patrick Exp $	*/
 
 /*
  * Copyright (c) 2010-2013 Reyk Floeter <reyk@openbsd.org>
@@ -643,7 +643,7 @@ ikev2_msg_send_encrypt(struct iked *env, struct iked_sa *sa, struct ibuf **ep,
 	    sa->sa_local.addr.ss_len, response)) == NULL)
 		goto done;
 
-	resp.msg_msgid = response ? sa->sa_msgid : ikev2_msg_id(env, sa);
+	resp.msg_msgid = response ? sa->sa_msgid_current : ikev2_msg_id(env, sa);
 
 	/* IKE header */
 	if ((hdr = ikev2_add_header(buf, sa, resp.msg_msgid, IKEV2_PAYLOAD_SK,