1 files changed, 355 insertions, 0 deletions
diff --git a/src/libcharon/sa/ikev1/iv_manager.c b/src/libcharon/sa/ikev1/iv_manager.c
new file mode 100644
index 000000000..c9f737ccd
--- /dev/null
+++ b/src/libcharon/sa/ikev1/iv_manager.c
@@ -0,0 +1,355 @@
+/*
+ * Copyright (C) 2011-2016 Tobias Brunner
+ * 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 "iv_manager.h"
+
+#include <collections/linked_list.h>
+
+/**
+ * Max. number of IVs/QMs to track.
+ */
+#define MAX_EXCHANGES_DEFAULT 3
+
+typedef struct private_iv_manager_t private_iv_manager_t;
+typedef struct iv_data_t iv_data_t;
+typedef struct qm_data_t qm_data_t;
+
+/**
+ * Data stored for IVs.
+ */
+struct iv_data_t {
+	/**
+	 * message ID
+	 */
+	uint32_t mid;
+
+	/**
+	 * current IV
+	 */
+	chunk_t iv;
+
+	/**
+	 * last block of encrypted message
+	 */
+	chunk_t last_block;
+};
+
+/**
+ * Private data of a iv_manager_t object.
+ */
+struct private_iv_manager_t {
+	/**
+	 * Implement public interface.
+	 */
+	iv_manager_t public;
+
+	/**
+	 * Phase 1 IV.
+	 */
+	iv_data_t phase1_iv;
+
+	/**
+	 * Keep track of IVs for exchanges after phase 1. We store only a limited
+	 * number of IVs in an MRU sort of way. Stores iv_data_t objects.
+	 */
+	linked_list_t *ivs;
+
+	/**
+	 * Keep track of Nonces during Quick Mode exchanges. Only a limited number
+	 * of QMs are tracked at the same time. Stores qm_data_t objects.
+	 */
+	linked_list_t *qms;
+
+	/**
+	 * Max. number of IVs/Quick Modes to track.
+	 */
+	int max_exchanges;
+
+	/**
+	 * Hasher used for IV generation.
+	 */
+	hasher_t *hasher;
+
+	/*
+	 * Encryption algorithm the block size.
+	 */
+	size_t block_size;
+};
+
+/**
+ * Data stored for Quick Mode exchanges.
+ */
+struct qm_data_t {
+	/**
+	 * Message ID.
+	 */
+	uint32_t mid;
+
+	/**
+	 * Ni_b (Nonce from first message).
+	 */
+	chunk_t n_i;
+
+	/**
+	 * Nr_b (Nonce from second message).
+	 */
+	chunk_t n_r;
+};
+
+/**
+ * Destroy an iv_data_t object.
+ */
+static void iv_data_destroy(iv_data_t *this)
+{
+	chunk_free(&this->last_block);
+	chunk_free(&this->iv);
+	free(this);
+}
+
+/**
+ * Destroy a qm_data_t object.
+ */
+static void qm_data_destroy(qm_data_t *this)
+{
+	chunk_free(&this->n_i);
+	chunk_free(&this->n_r);
+	free(this);
+}
+
+/**
+ * Generate an IV.
+ */
+static bool generate_iv(private_iv_manager_t *this, iv_data_t *iv)
+{
+	if (iv->mid == 0 || iv->iv.ptr)
+	{	/* use last block of previous encrypted message */
+		chunk_free(&iv->iv);
+		iv->iv = iv->last_block;
+		iv->last_block = chunk_empty;
+	}
+	else
+	{
+		/* initial phase 2 IV = hash(last_phase1_block | mid) */
+		uint32_t net;;
+		chunk_t data;
+
+		net = htonl(iv->mid);
+		data = chunk_cata("cc", this->phase1_iv.iv, chunk_from_thing(net));
+		if (!this->hasher->allocate_hash(this->hasher, data, &iv->iv))
+		{
+			return FALSE;
+		}
+		if (iv->iv.len > this->block_size)
+		{
+			iv->iv.len = this->block_size;
+		}
+	}
+	DBG4(DBG_IKE, "next IV for MID %u %B", iv->mid, &iv->iv);
+	return TRUE;
+}
+
+/**
+ * Try to find an IV for the given message ID, if not found, generate it.
+ */
+static iv_data_t *lookup_iv(private_iv_manager_t *this, uint32_t mid)
+{
+	enumerator_t *enumerator;
+	iv_data_t *iv, *found = NULL;
+
+	if (mid == 0)
+	{
+		return &this->phase1_iv;
+	}
+
+	enumerator = this->ivs->create_enumerator(this->ivs);
+	while (enumerator->enumerate(enumerator, &iv))
+	{
+		if (iv->mid == mid)
+		{	/* IV gets moved to the front of the list */
+			this->ivs->remove_at(this->ivs, enumerator);
+			found = iv;
+			break;
+		}
+	}
+	enumerator->destroy(enumerator);
+	if (!found)
+	{
+		INIT(found,
+			.mid = mid,
+		);
+		if (!generate_iv(this, found))
+		{
+			iv_data_destroy(found);
+			return NULL;
+		}
+	}
+	this->ivs->insert_first(this->ivs, found);
+	/* remove least recently used IV if maximum reached */
+	if (this->ivs->get_count(this->ivs) > this->max_exchanges &&
+		this->ivs->remove_last(this->ivs, (void**)&iv) == SUCCESS)
+	{
+		iv_data_destroy(iv);
+	}
+	return found;
+}
+
+METHOD(iv_manager_t, init_iv_chain, bool,
+	private_iv_manager_t *this, chunk_t data, hasher_t *hasher,
+	size_t block_size)
+{
+	this->hasher = hasher;
+	this->block_size = block_size;
+
+	if (!this->hasher->allocate_hash(this->hasher, data, &this->phase1_iv.iv))
+	{
+		return FALSE;
+	}
+	if (this->phase1_iv.iv.len > this->block_size)
+	{
+		this->phase1_iv.iv.len = this->block_size;
+	}
+	DBG4(DBG_IKE, "initial IV %B", &this->phase1_iv.iv);
+	return TRUE;
+}
+
+METHOD(iv_manager_t, get_iv, bool,
+	private_iv_manager_t *this, uint32_t mid, chunk_t *out)
+{
+	iv_data_t *iv;
+
+	iv = lookup_iv(this, mid);
+	if (iv)
+	{
+		*out = iv->iv;
+		return TRUE;
+	}
+	return FALSE;
+}
+
+METHOD(iv_manager_t, update_iv, bool,
+	private_iv_manager_t *this, uint32_t mid, chunk_t last_block)
+{
+	iv_data_t *iv = lookup_iv(this, mid);
+	if (iv)
+	{	/* update last block */
+		chunk_free(&iv->last_block);
+		iv->last_block = chunk_clone(last_block);
+		return TRUE;
+	}
+	return FALSE;
+}
+
+METHOD(iv_manager_t, confirm_iv, bool,
+	private_iv_manager_t *this, uint32_t mid)
+{
+	iv_data_t *iv = lookup_iv(this, mid);
+	if (iv)
+	{
+		return generate_iv(this, iv);
+	}
+	return FALSE;
+}
+
+METHOD(iv_manager_t, lookup_quick_mode, void,
+	private_iv_manager_t *this, uint32_t mid, chunk_t **n_i, chunk_t **n_r)
+{
+	enumerator_t *enumerator;
+	qm_data_t *qm, *found = NULL;
+
+	enumerator = this->qms->create_enumerator(this->qms);
+	while (enumerator->enumerate(enumerator, &qm))
+	{
+		if (qm->mid == mid)
+		{	/* state gets moved to the front of the list */
+			this->qms->remove_at(this->qms, enumerator);
+			found = qm;
+			break;
+		}
+	}
+	enumerator->destroy(enumerator);
+	if (!found)
+	{
+		INIT(found,
+			.mid = mid,
+		);
+	}
+
+	*n_i = &found->n_i;
+	*n_r = &found->n_r;
+
+	this->qms->insert_first(this->qms, found);
+	/* remove least recently used state if maximum reached */
+	if (this->qms->get_count(this->qms) > this->max_exchanges &&
+		this->qms->remove_last(this->qms, (void**)&qm) == SUCCESS)
+	{
+		qm_data_destroy(qm);
+	}
+}
+
+METHOD(iv_manager_t, remove_quick_mode, void,
+	private_iv_manager_t *this, uint32_t mid)
+{
+	enumerator_t *enumerator;
+	qm_data_t *qm;
+
+	enumerator = this->qms->create_enumerator(this->qms);
+	while (enumerator->enumerate(enumerator, &qm))
+	{
+		if (qm->mid == mid)
+		{
+			this->qms->remove_at(this->qms, enumerator);
+			qm_data_destroy(qm);
+			break;
+		}
+	}
+	enumerator->destroy(enumerator);
+}
+
+METHOD(iv_manager_t, destroy, void,
+	private_iv_manager_t *this)
+{
+	chunk_free(&this->phase1_iv.iv);
+	chunk_free(&this->phase1_iv.last_block);
+	this->ivs->destroy_function(this->ivs, (void*)iv_data_destroy);
+	this->qms->destroy_function(this->qms, (void*)qm_data_destroy);
+	free(this);
+}
+
+iv_manager_t *iv_manager_create(int max_exchanges)
+{
+	private_iv_manager_t *this;
+
+	INIT(this,
+		.public = {
+			.init_iv_chain = _init_iv_chain,
+			.get_iv = _get_iv,
+			.update_iv = _update_iv,
+			.confirm_iv = _confirm_iv,
+			.lookup_quick_mode = _lookup_quick_mode,
+			.remove_quick_mode = _remove_quick_mode,
+			.destroy = _destroy,
+		},
+		.ivs = linked_list_create(),
+		.qms = linked_list_create(),
+		.max_exchanges = max_exchanges,
+	);
+
+	if (!this->max_exchanges)
+	{
+		this->max_exchanges = lib->settings->get_int(lib->settings,
+					"%s.max_ikev1_exchanges", MAX_EXCHANGES_DEFAULT, lib->ns);
+	}
+	return &this->public;
+}