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-rw-r--r--src/libcharon/sa/ikev2/tasks/ike_natd.c472
1 files changed, 472 insertions, 0 deletions
diff --git a/src/libcharon/sa/ikev2/tasks/ike_natd.c b/src/libcharon/sa/ikev2/tasks/ike_natd.c
new file mode 100644
index 000000000..0a93db9ed
--- /dev/null
+++ b/src/libcharon/sa/ikev2/tasks/ike_natd.c
@@ -0,0 +1,472 @@
+/*
+ * Copyright (C) 2006-2007 Martin Willi
+ * Copyright (C) 2006 Tobias Brunner, Daniel Roethlisberger
+ * Hochschule fuer Technik Rapperswil
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; either version 2 of the License, or (at your
+ * option) any later version. See <http://www.fsf.org/copyleft/gpl.txt>.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
+ * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
+ * for more details.
+ */
+
+#include "ike_natd.h"
+
+#include <string.h>
+
+#include <hydra.h>
+#include <daemon.h>
+#include <config/peer_cfg.h>
+#include <crypto/hashers/hasher.h>
+#include <encoding/payloads/notify_payload.h>
+
+
+typedef struct private_ike_natd_t private_ike_natd_t;
+
+/**
+ * Private members of a ike_natd_t task.
+ */
+struct private_ike_natd_t {
+
+ /**
+ * Public methods and task_t interface.
+ */
+ ike_natd_t public;
+
+ /**
+ * Assigned IKE_SA.
+ */
+ ike_sa_t *ike_sa;
+
+ /**
+ * Are we the initiator?
+ */
+ bool initiator;
+
+ /**
+ * Hasher used to build NAT detection hashes
+ */
+ hasher_t *hasher;
+
+ /**
+ * Did we process any NAT detection notifys for a source address?
+ */
+ bool src_seen;
+
+ /**
+ * Did we process any NAT detection notifys for a destination address?
+ */
+ bool dst_seen;
+
+ /**
+ * Have we found a matching source address NAT hash?
+ */
+ bool src_matched;
+
+ /**
+ * Have we found a matching destination address NAT hash?
+ */
+ bool dst_matched;
+
+ /**
+ * whether NAT mappings for our NATed address has changed
+ */
+ bool mapping_changed;
+};
+
+
+/**
+ * Build NAT detection hash for a host
+ */
+static chunk_t generate_natd_hash(private_ike_natd_t *this,
+ ike_sa_id_t *ike_sa_id, host_t *host)
+{
+ chunk_t natd_chunk, spi_i_chunk, spi_r_chunk, addr_chunk, port_chunk;
+ chunk_t natd_hash;
+ u_int64_t spi_i, spi_r;
+ u_int16_t port;
+
+ /* prepare all required chunks */
+ spi_i = ike_sa_id->get_initiator_spi(ike_sa_id);
+ spi_r = ike_sa_id->get_responder_spi(ike_sa_id);
+ spi_i_chunk.ptr = (void*)&spi_i;
+ spi_i_chunk.len = sizeof(spi_i);
+ spi_r_chunk.ptr = (void*)&spi_r;
+ spi_r_chunk.len = sizeof(spi_r);
+ port = htons(host->get_port(host));
+ port_chunk.ptr = (void*)&port;
+ port_chunk.len = sizeof(port);
+ addr_chunk = host->get_address(host);
+
+ /* natd_hash = SHA1( spi_i | spi_r | address | port ) */
+ natd_chunk = chunk_cat("cccc", spi_i_chunk, spi_r_chunk, addr_chunk, port_chunk);
+ if (!this->hasher->allocate_hash(this->hasher, natd_chunk, &natd_hash))
+ {
+ natd_hash = chunk_empty;
+ }
+ DBG3(DBG_IKE, "natd_chunk %B", &natd_chunk);
+ DBG3(DBG_IKE, "natd_hash %B", &natd_hash);
+
+ chunk_free(&natd_chunk);
+ return natd_hash;
+}
+
+/**
+ * build a faked NATD payload to enforce UDP encap
+ */
+static chunk_t generate_natd_hash_faked(private_ike_natd_t *this)
+{
+ rng_t *rng;
+ chunk_t chunk;
+
+ rng = lib->crypto->create_rng(lib->crypto, RNG_WEAK);
+ if (!rng || !rng->allocate_bytes(rng, HASH_SIZE_SHA1, &chunk))
+ {
+ DBG1(DBG_IKE, "unable to get random bytes for NATD fake");
+ DESTROY_IF(rng);
+ return chunk_empty;
+ }
+ rng->destroy(rng);
+ return chunk;
+}
+
+/**
+ * Build a NAT detection notify payload.
+ */
+static notify_payload_t *build_natd_payload(private_ike_natd_t *this,
+ notify_type_t type, host_t *host)
+{
+ chunk_t hash;
+ notify_payload_t *notify;
+ ike_sa_id_t *ike_sa_id;
+ ike_cfg_t *config;
+
+ ike_sa_id = this->ike_sa->get_id(this->ike_sa);
+ config = this->ike_sa->get_ike_cfg(this->ike_sa);
+ if (config->force_encap(config) && type == NAT_DETECTION_SOURCE_IP)
+ {
+ hash = generate_natd_hash_faked(this);
+ }
+ else
+ {
+ hash = generate_natd_hash(this, ike_sa_id, host);
+ }
+ if (!hash.len)
+ {
+ return NULL;
+ }
+ notify = notify_payload_create(NOTIFY);
+ notify->set_notify_type(notify, type);
+ notify->set_notification_data(notify, hash);
+ chunk_free(&hash);
+
+ return notify;
+}
+
+/**
+ * read notifys from message and evaluate them
+ */
+static void process_payloads(private_ike_natd_t *this, message_t *message)
+{
+ enumerator_t *enumerator;
+ payload_t *payload;
+ notify_payload_t *notify;
+ chunk_t hash, src_hash, dst_hash;
+ ike_sa_id_t *ike_sa_id;
+ host_t *me, *other;
+ ike_cfg_t *config;
+
+ /* Precompute NAT-D hashes for incoming NAT notify comparison */
+ ike_sa_id = message->get_ike_sa_id(message);
+ me = message->get_destination(message);
+ other = message->get_source(message);
+ dst_hash = generate_natd_hash(this, ike_sa_id, me);
+ src_hash = generate_natd_hash(this, ike_sa_id, other);
+
+ DBG3(DBG_IKE, "precalculated src_hash %B", &src_hash);
+ DBG3(DBG_IKE, "precalculated dst_hash %B", &dst_hash);
+
+ enumerator = message->create_payload_enumerator(message);
+ while (enumerator->enumerate(enumerator, &payload))
+ {
+ if (payload->get_type(payload) != NOTIFY)
+ {
+ continue;
+ }
+ notify = (notify_payload_t*)payload;
+ switch (notify->get_notify_type(notify))
+ {
+ case NAT_DETECTION_DESTINATION_IP:
+ {
+ this->dst_seen = TRUE;
+ hash = notify->get_notification_data(notify);
+ if (!this->dst_matched)
+ {
+ DBG3(DBG_IKE, "received dst_hash %B", &hash);
+ if (chunk_equals(hash, dst_hash))
+ {
+ this->dst_matched = TRUE;
+ }
+ }
+ /* RFC4555 says we should also compare against IKE_SA_INIT
+ * NATD payloads, but this does not work: We are running
+ * there at port 500, but use 4500 afterwards... */
+ if (message->get_exchange_type(message) == INFORMATIONAL &&
+ this->initiator && !this->dst_matched)
+ {
+ this->mapping_changed = this->ike_sa->has_mapping_changed(
+ this->ike_sa, hash);
+ }
+ break;
+ }
+ case NAT_DETECTION_SOURCE_IP:
+ {
+ this->src_seen = TRUE;
+ if (!this->src_matched)
+ {
+ hash = notify->get_notification_data(notify);
+ DBG3(DBG_IKE, "received src_hash %B", &hash);
+ if (chunk_equals(hash, src_hash))
+ {
+ this->src_matched = TRUE;
+ }
+ }
+ break;
+ }
+ default:
+ break;
+ }
+ }
+ enumerator->destroy(enumerator);
+
+ chunk_free(&src_hash);
+ chunk_free(&dst_hash);
+
+ if (this->src_seen && this->dst_seen)
+ {
+ this->ike_sa->enable_extension(this->ike_sa, EXT_NATT);
+
+ this->ike_sa->set_condition(this->ike_sa, COND_NAT_HERE,
+ !this->dst_matched);
+ this->ike_sa->set_condition(this->ike_sa, COND_NAT_THERE,
+ !this->src_matched);
+ config = this->ike_sa->get_ike_cfg(this->ike_sa);
+ if (this->dst_matched && this->src_matched &&
+ config->force_encap(config))
+ {
+ this->ike_sa->set_condition(this->ike_sa, COND_NAT_FAKE, TRUE);
+ }
+ }
+}
+
+METHOD(task_t, process_i, status_t,
+ private_ike_natd_t *this, message_t *message)
+{
+ process_payloads(this, message);
+
+ if (message->get_exchange_type(message) == IKE_SA_INIT)
+ {
+ peer_cfg_t *peer_cfg = this->ike_sa->get_peer_cfg(this->ike_sa);
+ if (this->ike_sa->has_condition(this->ike_sa, COND_NAT_ANY) ||
+ /* if peer supports NAT-T, we switch to port 4500 even
+ * if no NAT is detected. can't be done later (when we would know
+ * whether the peer supports MOBIKE) because there would be no
+ * exchange to actually do the switch (other than a forced DPD). */
+ (peer_cfg->use_mobike(peer_cfg) &&
+ this->ike_sa->supports_extension(this->ike_sa, EXT_NATT)))
+ {
+ this->ike_sa->float_ports(this->ike_sa);
+ }
+ }
+
+ return SUCCESS;
+}
+
+METHOD(task_t, build_i, status_t,
+ private_ike_natd_t *this, message_t *message)
+{
+ notify_payload_t *notify;
+ enumerator_t *enumerator;
+ ike_cfg_t *ike_cfg;
+ host_t *host;
+
+ if (this->hasher == NULL)
+ {
+ DBG1(DBG_IKE, "unable to build NATD payloads, SHA1 not supported");
+ return NEED_MORE;
+ }
+
+ ike_cfg = this->ike_sa->get_ike_cfg(this->ike_sa);
+
+ /* destination is always set */
+ host = message->get_destination(message);
+ notify = build_natd_payload(this, NAT_DETECTION_DESTINATION_IP, host);
+ if (notify)
+ {
+ message->add_payload(message, (payload_t*)notify);
+ }
+
+ /* source may be any, we have 3 possibilities to get our source address:
+ * 1. It is defined in the config => use the one of the IKE_SA
+ * 2. We do a routing lookup in the kernel interface
+ * 3. Include all possbile addresses
+ */
+ host = message->get_source(message);
+ if (!host->is_anyaddr(host) || ike_cfg->force_encap(ike_cfg))
+ { /* 1. or if we force UDP encap, as it doesn't matter if it's %any */
+ notify = build_natd_payload(this, NAT_DETECTION_SOURCE_IP, host);
+ if (notify)
+ {
+ message->add_payload(message, (payload_t*)notify);
+ }
+ }
+ else
+ {
+ host = hydra->kernel_interface->get_source_addr(hydra->kernel_interface,
+ this->ike_sa->get_other_host(this->ike_sa), NULL);
+ if (host)
+ { /* 2. */
+ host->set_port(host, ike_cfg->get_my_port(ike_cfg));
+ notify = build_natd_payload(this, NAT_DETECTION_SOURCE_IP, host);
+ if (notify)
+ {
+ message->add_payload(message, (payload_t*)notify);
+ }
+ host->destroy(host);
+ }
+ else
+ { /* 3. */
+ enumerator = hydra->kernel_interface->create_address_enumerator(
+ hydra->kernel_interface, ADDR_TYPE_REGULAR);
+ while (enumerator->enumerate(enumerator, (void**)&host))
+ {
+ /* apply port 500 to host, but work on a copy */
+ host = host->clone(host);
+ host->set_port(host, ike_cfg->get_my_port(ike_cfg));
+ notify = build_natd_payload(this, NAT_DETECTION_SOURCE_IP, host);
+ host->destroy(host);
+ if (notify)
+ {
+ message->add_payload(message, (payload_t*)notify);
+ }
+ }
+ enumerator->destroy(enumerator);
+ }
+ }
+ return NEED_MORE;
+}
+
+METHOD(task_t, build_r, status_t,
+ private_ike_natd_t *this, message_t *message)
+{
+ notify_payload_t *notify;
+ host_t *me, *other;
+
+ /* only add notifies on successful responses. */
+ if (message->get_exchange_type(message) == IKE_SA_INIT &&
+ message->get_payload(message, SECURITY_ASSOCIATION) == NULL)
+ {
+ return SUCCESS;
+ }
+
+ if (this->src_seen && this->dst_seen)
+ {
+ if (this->hasher == NULL)
+ {
+ DBG1(DBG_IKE, "unable to build NATD payloads, SHA1 not supported");
+ return SUCCESS;
+ }
+
+ /* initiator seems to support NAT detection, add response */
+ me = message->get_source(message);
+ notify = build_natd_payload(this, NAT_DETECTION_SOURCE_IP, me);
+ if (notify)
+ {
+ message->add_payload(message, (payload_t*)notify);
+ }
+ other = message->get_destination(message);
+ notify = build_natd_payload(this, NAT_DETECTION_DESTINATION_IP, other);
+ if (notify)
+ {
+ message->add_payload(message, (payload_t*)notify);
+ }
+ }
+ return SUCCESS;
+}
+
+METHOD(task_t, process_r, status_t,
+ private_ike_natd_t *this, message_t *message)
+{
+ process_payloads(this, message);
+
+ return NEED_MORE;
+}
+
+METHOD(task_t, get_type, task_type_t,
+ private_ike_natd_t *this)
+{
+ return TASK_IKE_NATD;
+}
+
+METHOD(task_t, migrate, void,
+ private_ike_natd_t *this, ike_sa_t *ike_sa)
+{
+ this->ike_sa = ike_sa;
+ this->src_seen = FALSE;
+ this->dst_seen = FALSE;
+ this->src_matched = FALSE;
+ this->dst_matched = FALSE;
+ this->mapping_changed = FALSE;
+}
+
+METHOD(task_t, destroy, void,
+ private_ike_natd_t *this)
+{
+ DESTROY_IF(this->hasher);
+ free(this);
+}
+
+METHOD(ike_natd_t, has_mapping_changed, bool,
+ private_ike_natd_t *this)
+{
+ return this->mapping_changed;
+}
+
+/*
+ * Described in header.
+ */
+ike_natd_t *ike_natd_create(ike_sa_t *ike_sa, bool initiator)
+{
+ private_ike_natd_t *this;
+
+ INIT(this,
+ .public = {
+ .task = {
+ .get_type = _get_type,
+ .migrate = _migrate,
+ .destroy = _destroy,
+ },
+ .has_mapping_changed = _has_mapping_changed,
+ },
+ .ike_sa = ike_sa,
+ .initiator = initiator,
+ .hasher = lib->crypto->create_hasher(lib->crypto, HASH_SHA1),
+ );
+
+ if (initiator)
+ {
+ this->public.task.build = _build_i;
+ this->public.task.process = _process_i;
+ }
+ else
+ {
+ this->public.task.build = _build_r;
+ this->public.task.process = _process_r;
+ }
+
+ return &this->public;
+}