1 files changed, 439 insertions, 0 deletions
diff --git a/keyexchange/isakmpd-20041012/nat_traversal.c b/keyexchange/isakmpd-20041012/nat_traversal.c
new file mode 100644
index 0000000..86d2d57
--- /dev/null
+++ b/keyexchange/isakmpd-20041012/nat_traversal.c
@@ -0,0 +1,439 @@
+/*	$OpenBSD: nat_traversal.c,v 1.17 2006/06/14 14:03:33 hshoexer Exp $	*/
+
+/*
+ * Copyright (c) 2004 Håkan Olsson.  All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+ * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+ * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <sys/types.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "sysdep.h"
+
+#include "conf.h"
+#include "exchange.h"
+#include "hash.h"
+#include "ipsec.h"
+#include "isakmp_fld.h"
+#include "isakmp_num.h"
+#include "ipsec_num.h"
+#include "hash.h"
+#include "log.h"
+#include "message.h"
+#include "nat_traversal.h"
+#include "prf.h"
+#include "sa.h"
+#include "timer.h"
+#include "transport.h"
+#include "util.h"
+#include "virtual.h"
+
+int	disable_nat_t = 0;
+
+/*
+ * NAT-T capability of the other peer is determined by a particular vendor
+ * ID sent in the first message. This vendor ID string is supposed to be a
+ * MD5 hash of "RFC 3947".
+ *
+ * These seem to be the "well" known variants of this string in use by
+ * products today.
+ */
+
+static struct nat_t_cap isakmp_nat_t_cap[] = {
+	{ VID_DRAFT_V2_N, EXCHANGE_FLAG_NAT_T_DRAFT,
+	  "draft-ietf-ipsec-nat-t-ike-02\n", NULL, 0 },
+	{ VID_DRAFT_V3, EXCHANGE_FLAG_NAT_T_DRAFT,
+	  "draft-ietf-ipsec-nat-t-ike-03", NULL, 0 },
+	{ VID_RFC3947, EXCHANGE_FLAG_NAT_T_RFC,
+	  "RFC 3947", NULL, 0 },
+};
+
+#define NUMNATTCAP	(sizeof isakmp_nat_t_cap / sizeof isakmp_nat_t_cap[0])
+
+/* In seconds. Recommended in draft-ietf-ipsec-udp-encaps-09.  */
+#define NAT_T_KEEPALIVE_INTERVAL	20
+
+static int	nat_t_setup_hashes(void);
+static int	nat_t_add_vendor_payload(struct message *, struct nat_t_cap *);
+static int	nat_t_add_nat_d(struct message *, struct sockaddr *);
+static int	nat_t_match_nat_d_payload(struct message *, struct sockaddr *);
+
+void
+nat_t_init(void)
+{
+	nat_t_setup_hashes();
+}
+
+/* Generate the NAT-T capability marker hashes. Executed only once.  */
+static int
+nat_t_setup_hashes(void)
+{
+	struct hash *hash;
+	int n = NUMNATTCAP;
+	int i;
+
+	/* The draft says to use MD5.  */
+	hash = hash_get(HASH_MD5);
+	if (!hash) {
+		/* Should never happen.  */
+		log_print("nat_t_setup_hashes: "
+		    "could not find MD5 hash structure!");
+		return -1;
+	}
+
+	/* Populate isakmp_nat_t_cap with hashes.  */
+	for (i = 0; i < n; i++) {
+		isakmp_nat_t_cap[i].hashsize = hash->hashsize;
+		isakmp_nat_t_cap[i].hash = (char *)malloc(hash->hashsize);
+		if (!isakmp_nat_t_cap[i].hash) {
+			log_error("nat_t_setup_hashes: malloc (%lu) failed",
+			    (unsigned long)hash->hashsize);
+			goto errout;
+		}
+
+		hash->Init(hash->ctx);
+		hash->Update(hash->ctx,
+		    (unsigned char *)isakmp_nat_t_cap[i].text,
+		    strlen(isakmp_nat_t_cap[i].text));
+		hash->Final(isakmp_nat_t_cap[i].hash, hash->ctx);
+
+		LOG_DBG((LOG_EXCHANGE, 50, "nat_t_setup_hashes: "
+		    "MD5(\"%s\") (%lu bytes)", isakmp_nat_t_cap[i].text,
+		    (unsigned long)hash->hashsize));
+		LOG_DBG_BUF((LOG_EXCHANGE, 50, "nat_t_setup_hashes",
+		    isakmp_nat_t_cap[i].hash, hash->hashsize));
+	}
+
+	return 0;
+
+errout:
+	for (i = 0; i < n; i++)
+		if (isakmp_nat_t_cap[i].hash)
+			free(isakmp_nat_t_cap[i].hash);
+	return -1;
+}
+
+/* Add one NAT-T VENDOR payload.  */
+static int
+nat_t_add_vendor_payload(struct message *msg, struct nat_t_cap *cap)
+{
+	size_t	  buflen = cap->hashsize + ISAKMP_GEN_SZ;
+	u_int8_t *buf;
+
+	if (disable_nat_t)
+		return 0;
+
+	buf = malloc(buflen);
+	if (!buf) {
+		log_error("nat_t_add_vendor_payload: malloc (%lu) failed",
+		    (unsigned long)buflen);
+		return -1;
+	}
+
+	SET_ISAKMP_GEN_LENGTH(buf, buflen);
+	memcpy(buf + ISAKMP_VENDOR_ID_OFF, cap->hash, cap->hashsize);
+	if (message_add_payload(msg, ISAKMP_PAYLOAD_VENDOR, buf, buflen, 1)) {
+		free(buf);
+		return -1;
+	}
+	return 0;
+}
+
+/* Add the NAT-T capability markers (VENDOR payloads).  */
+int
+nat_t_add_vendor_payloads(struct message *msg)
+{
+	int i;
+
+	if (disable_nat_t)
+		return 0;
+
+	for (i = 0; i < NUMNATTCAP; i++)
+		if (nat_t_add_vendor_payload(msg, &isakmp_nat_t_cap[i]))
+			return -1;
+	return 0;
+}
+
+/*
+ * Check an incoming message for NAT-T capability markers.
+ */
+void
+nat_t_check_vendor_payload(struct message *msg, struct payload *p)
+{
+	u_int8_t *pbuf = p->p;
+	size_t	  vlen;
+	int	  i;
+
+	if (disable_nat_t)
+		return;
+
+	vlen = GET_ISAKMP_GEN_LENGTH(pbuf) - ISAKMP_GEN_SZ;
+
+	for (i = 0; i < NUMNATTCAP; i++) {
+		if (vlen != isakmp_nat_t_cap[i].hashsize) {
+			LOG_DBG((LOG_EXCHANGE, 50, "nat_t_check_vendor_payload: "
+			    "bad size %lu != %lu", (unsigned long)vlen,
+			    (unsigned long)isakmp_nat_t_cap[i].hashsize));
+			continue;
+		}
+		if (memcmp(isakmp_nat_t_cap[i].hash, pbuf + ISAKMP_GEN_SZ,
+		    vlen) == 0) {
+			/* This peer is NAT-T capable.  */
+			msg->exchange->flags |= EXCHANGE_FLAG_NAT_T_CAP_PEER;
+			msg->exchange->flags |= isakmp_nat_t_cap[i].flags;
+			LOG_DBG((LOG_EXCHANGE, 10,
+			    "nat_t_check_vendor_payload: "
+			    "NAT-T capable peer detected"));
+			p->flags |= PL_MARK;
+		}
+	}
+
+	return;
+}
+
+/* Generate the NAT-D payload hash : HASH(CKY-I | CKY-R | IP | Port).  */
+static u_int8_t *
+nat_t_generate_nat_d_hash(struct message *msg, struct sockaddr *sa,
+    size_t *hashlen)
+{
+	struct ipsec_exch *ie = (struct ipsec_exch *)msg->exchange->data;
+	struct hash	 *hash;
+	u_int8_t	 *res;
+	in_port_t	  port;
+
+	hash = hash_get(ie->hash->type);
+	if (hash == NULL) {
+		log_print ("nat_t_generate_nat_d_hash: no hash");
+		return NULL;
+	}
+
+	*hashlen = hash->hashsize;
+
+	res = (u_int8_t *)malloc((unsigned long)*hashlen);
+	if (!res) {
+		log_print("nat_t_generate_nat_d_hash: malloc (%lu) failed",
+		    (unsigned long)*hashlen);
+		*hashlen = 0;
+		return NULL;
+	}
+
+	port = sockaddr_port(sa);
+	bzero(res, *hashlen);
+
+	hash->Init(hash->ctx);
+	hash->Update(hash->ctx, msg->exchange->cookies,
+	    sizeof msg->exchange->cookies);
+	hash->Update(hash->ctx, sockaddr_addrdata(sa), sockaddr_addrlen(sa));
+	hash->Update(hash->ctx, (unsigned char *)&port, sizeof port);
+	hash->Final(res, hash->ctx);
+	return res;
+}
+
+/* Add a NAT-D payload to our message.  */
+static int
+nat_t_add_nat_d(struct message *msg, struct sockaddr *sa)
+{
+	int	  ret;
+	u_int8_t *hbuf, *buf;
+	size_t	  hbuflen, buflen;
+
+	hbuf = nat_t_generate_nat_d_hash(msg, sa, &hbuflen);
+	if (!hbuf) {
+		log_print("nat_t_add_nat_d: NAT-D hash gen failed");
+		return -1;
+	}
+
+	buflen = ISAKMP_NAT_D_DATA_OFF + hbuflen;
+	buf = malloc(buflen);
+	if (!buf) {
+		log_error("nat_t_add_nat_d: malloc (%lu) failed",
+		    (unsigned long)buflen);
+		free(hbuf);
+		return -1;
+	}
+
+	SET_ISAKMP_GEN_LENGTH(buf, buflen);
+	memcpy(buf + ISAKMP_NAT_D_DATA_OFF, hbuf, hbuflen);
+	free(hbuf);
+
+	if (msg->exchange->flags & EXCHANGE_FLAG_NAT_T_RFC)
+		ret = message_add_payload(msg, ISAKMP_PAYLOAD_NAT_D, buf,
+		    buflen, 1);
+	else if (msg->exchange->flags & EXCHANGE_FLAG_NAT_T_DRAFT)
+		ret = message_add_payload(msg, ISAKMP_PAYLOAD_NAT_D_DRAFT,
+		    buf, buflen, 1);
+	else
+		ret = -1;
+		
+	if (ret) {
+		free(buf);
+		return -1;
+	}
+	return 0;
+}
+
+/* We add two NAT-D payloads, one each for src and dst.  */
+int
+nat_t_exchange_add_nat_d(struct message *msg)
+{
+	struct sockaddr *sa;
+
+	/* Remote address first. */
+	msg->transport->vtbl->get_dst(msg->transport, &sa);
+	if (nat_t_add_nat_d(msg, sa))
+		return -1;
+
+	msg->transport->vtbl->get_src(msg->transport, &sa);
+	if (nat_t_add_nat_d(msg, sa))
+		return -1;
+	return 0;
+}
+
+/* Generate and match a NAT-D hash against the NAT-D payload (pl.) data.  */
+static int
+nat_t_match_nat_d_payload(struct message *msg, struct sockaddr *sa)
+{
+	struct payload *p;
+	u_int8_t *hbuf;
+	size_t	 hbuflen;
+	int	 found = 0;
+
+	/*
+	 * If there are no NAT-D payloads in the message, return "found"
+	 * as this will avoid NAT-T (see nat_t_exchange_check_nat_d()).
+	 */
+	if ((p = payload_first(msg, ISAKMP_PAYLOAD_NAT_D_DRAFT)) == NULL &&
+	    (p = payload_first(msg, ISAKMP_PAYLOAD_NAT_D)) == NULL)
+		return 1;
+
+	hbuf = nat_t_generate_nat_d_hash(msg, sa, &hbuflen);
+	if (!hbuf)
+		return 0;
+
+	while (p) {
+		if (GET_ISAKMP_GEN_LENGTH (p->p) !=
+		    hbuflen + ISAKMP_NAT_D_DATA_OFF)
+			continue;
+
+		if (memcmp(p->p + ISAKMP_NAT_D_DATA_OFF, hbuf, hbuflen) == 0) {
+			found++;
+			break;
+		}
+		p = TAILQ_NEXT(p, link);
+	}
+	free(hbuf);
+	return found;
+}
+
+/*
+ * Check if we need to activate NAT-T, and if we need to send keepalive
+ * messages to the other side, i.e if we are a nat:ed peer.
+ */
+int
+nat_t_exchange_check_nat_d(struct message *msg)
+{
+	struct sockaddr *sa;
+	int	 outgoing_path_is_clear, incoming_path_is_clear;
+
+	/* Assume trouble, i.e NAT-boxes in our path.  */
+	outgoing_path_is_clear = incoming_path_is_clear = 0;
+
+	msg->transport->vtbl->get_src(msg->transport, &sa);
+	if (nat_t_match_nat_d_payload(msg, sa))
+		outgoing_path_is_clear = 1;
+
+	msg->transport->vtbl->get_dst(msg->transport, &sa);
+	if (nat_t_match_nat_d_payload(msg, sa))
+		incoming_path_is_clear = 1;
+
+	if (outgoing_path_is_clear && incoming_path_is_clear) {
+		LOG_DBG((LOG_EXCHANGE, 40, "nat_t_exchange_check_nat_d: "
+		    "no NAT"));
+		return 0; /* No NAT-T required.  */
+	}
+
+	/* NAT-T handling required.  */
+	msg->exchange->flags |= EXCHANGE_FLAG_NAT_T_ENABLE;
+
+	if (!outgoing_path_is_clear) {
+		msg->exchange->flags |= EXCHANGE_FLAG_NAT_T_KEEPALIVE;
+		LOG_DBG((LOG_EXCHANGE, 10, "nat_t_exchange_check_nat_d: "
+		    "NAT detected, we're behind it"));
+	} else
+		LOG_DBG ((LOG_EXCHANGE, 10,
+		    "nat_t_exchange_check_nat_d: NAT detected"));
+	return 1;
+}
+
+static void
+nat_t_send_keepalive(void *v_arg)
+{
+	struct sa *sa = (struct sa *)v_arg;
+	struct transport *t;
+	struct timeval now;
+	int interval;
+
+	/* Send the keepalive message.  */
+	t = ((struct virtual_transport *)sa->transport)->encap;
+	t->vtbl->send_message(NULL, t);
+
+	/* Set new timer.  */
+	interval = conf_get_num("General", "NAT-T-Keepalive", 0);
+	if (interval < 1)
+		interval = NAT_T_KEEPALIVE_INTERVAL;
+	gettimeofday(&now, 0);
+	now.tv_sec += interval;
+
+	sa->nat_t_keepalive = timer_add_event("nat_t_send_keepalive",
+	    nat_t_send_keepalive, v_arg, &now);
+	if (!sa->nat_t_keepalive)
+		log_print("nat_t_send_keepalive: "
+		    "timer_add_event() failed, will send no more keepalives");
+}
+
+void
+nat_t_setup_keepalive(struct sa *sa)
+{
+	struct sockaddr *src;
+	struct timeval now;
+
+	if (sa->initiator)
+		sa->transport->vtbl->get_src(sa->transport, &src);
+	else
+		sa->transport->vtbl->get_dst(sa->transport, &src);
+
+	if (!virtual_listen_lookup(src))
+		return;
+
+	gettimeofday(&now, 0);
+	now.tv_sec += NAT_T_KEEPALIVE_INTERVAL;
+
+	sa->nat_t_keepalive = timer_add_event("nat_t_send_keepalive",
+	    nat_t_send_keepalive, sa, &now);
+	if (!sa->nat_t_keepalive)
+		log_print("nat_t_setup_keepalive: "
+		    "timer_add_event() failed, will not send keepalives");
+
+	LOG_DBG((LOG_TRANSPORT, 50, "nat_t_setup_keepalive: "
+	    "added event for phase 1 SA %p", sa));
+}