Add initial TKM Diffie-Hellman implementation

The tkm_diffie_hellman_t plugin acquires a DH context from the Trusted
Key Manager and uses it to get a DH public value and the calculated
shared secret. Proper context handling is still missing though, the
plugin currently uses context ID 1.

The get_shared_secret function will be removed as soon as the TKM
specific keymat is ready.

src/charon-tkm/Makefile.am

@@ -24,7 +24,6 @@ BUILD_OPTS = \
 PLUGINS = \
 	aes \
 	constraints \
-	gmp \
 	hmac \
 	kernel-netlink \
 	pem \

src/charon-tkm/src/charon-tkm.c

@@ -34,6 +34,7 @@
 
 #include "tkm.h"
 #include "tkm_nonceg.h"
+#include "tkm_diffie_hellman.h"
 
 /**
  * PID file, in which charon-tkm stores its process id
@@ -271,7 +272,10 @@ int main(int argc, char *argv[])
 	/* register TKM specific plugins */
 	static plugin_feature_t features[] = {
 		PLUGIN_REGISTER(NONCE_GEN, tkm_nonceg_create),
-		PLUGIN_PROVIDE(NONCE_GEN)
+			PLUGIN_PROVIDE(NONCE_GEN),
+		PLUGIN_REGISTER(DH, tkm_diffie_hellman_create),
+			PLUGIN_PROVIDE(DH, MODP_3072_BIT),
+			PLUGIN_PROVIDE(DH, MODP_4096_BIT),
 	};
 	lib->plugins->add_static_features(lib->plugins, "tkm-backend", features,
 			countof(features), TRUE);

src/charon-tkm/src/tkm/tkm_diffie_hellman.c

@@ -0,0 +1,126 @@
+/*
+ * Copyrigth (C) 2012 Reto Buerki
+ * Copyright (C) 2012 Adrian-Ken Rueegsegger
+ * 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 <tkm/client.h>
+#include <tkm/constants.h>
+
+#include "tkm_diffie_hellman.h"
+
+#include <utils/debug.h>
+
+typedef struct private_tkm_diffie_hellman_t private_tkm_diffie_hellman_t;
+
+/**
+ * Private data of a tkm_diffie_hellman_t object.
+ */
+struct private_tkm_diffie_hellman_t {
+	/**
+	 * Public tkm_diffie_hellman_t interface.
+	 */
+	tkm_diffie_hellman_t public;
+
+	/**
+	 * Diffie Hellman group number.
+	 */
+	u_int16_t group;
+
+	/**
+	 * Diffie Hellman public value.
+	 */
+	dh_pubvalue_type pubvalue;
+};
+
+METHOD(diffie_hellman_t, get_my_public_value, void,
+	private_tkm_diffie_hellman_t *this, chunk_t *value)
+{
+	*value = chunk_alloc(this->pubvalue.size);
+	memcpy(value->ptr, &this->pubvalue.data, value->len);
+}
+
+METHOD(diffie_hellman_t, get_shared_secret, status_t,
+	private_tkm_diffie_hellman_t *this, chunk_t *secret)
+{
+	dh_key_type shared_secret;
+	if (ike_dh_get_shared_secret(1, &shared_secret) != TKM_OK)
+	{
+		return FAILED;
+	}
+
+	*secret = chunk_alloc(shared_secret.size);
+	memcpy(secret->ptr, &shared_secret.data, secret->len);
+	return SUCCESS;
+}
+
+
+METHOD(diffie_hellman_t, set_other_public_value, void,
+	private_tkm_diffie_hellman_t *this, chunk_t value)
+{
+	// TODO: unvoid this function
+
+	dh_pubvalue_type othervalue;
+	othervalue.size = value.len;
+	memcpy(&othervalue.data, value.ptr, value.len);
+
+	ike_dh_generate_key(1, othervalue);
+}
+
+METHOD(diffie_hellman_t, get_dh_group, diffie_hellman_group_t,
+	private_tkm_diffie_hellman_t *this)
+{
+	return this->group;
+}
+
+METHOD(diffie_hellman_t, destroy, void,
+	private_tkm_diffie_hellman_t *this)
+{
+	// TODO: unvoid this function
+
+	free(this);
+	if (ike_dh_reset(1) != TKM_OK)
+	{
+		DBG1(DBG_LIB, "resetting DH context 1 failed");
+	}
+}
+
+/*
+ * Described in header.
+ */
+tkm_diffie_hellman_t *tkm_diffie_hellman_create(diffie_hellman_group_t group)
+{
+	private_tkm_diffie_hellman_t *this;
+
+	INIT(this,
+		.public = {
+			.dh = {
+				.get_shared_secret = _get_shared_secret,
+				.set_other_public_value = _set_other_public_value,
+				.get_my_public_value = _get_my_public_value,
+				.get_dh_group = _get_dh_group,
+				.destroy = _destroy,
+			},
+		},
+	);
+
+	if (ike_dh_create(1, group, &this->pubvalue) != TKM_OK)
+	{
+		free(this);
+		return NULL;
+	}
+
+	this->group = group;
+
+	return &this->public;
+}

src/charon-tkm/src/tkm/tkm_diffie_hellman.h

@@ -0,0 +1,43 @@
+/*
+ * Copyright (C) 2012 Reto Buerki
+ * Copyright (C) 2012 Adrian-Ken Rueegsegger
+ * 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.
+ */
+
+#ifndef TKM_DIFFIE_HELLMAN_H_
+#define TKM_DIFFIE_HELLMAN_H_
+
+typedef struct tkm_diffie_hellman_t tkm_diffie_hellman_t;
+
+#include <library.h>
+
+/**
+ * diffie_hellman_t implementation using the trusted key manager.
+ */
+struct tkm_diffie_hellman_t {
+
+	/**
+	 * Implements diffie_hellman_t interface.
+	 */
+	diffie_hellman_t dh;
+};
+
+/**
+ * Creates a new tkm_diffie_hellman_t object.
+ *
+ * @param group			Diffie Hellman group number to use
+ * @return				tkm_diffie_hellman_t object, NULL if not supported
+ */
+tkm_diffie_hellman_t *tkm_diffie_hellman_create(diffie_hellman_group_t group);
+
+#endif /** TKM_DIFFIE_HELLMAN_H_ */

src/charon-tkm/tests/diffie_hellman_tests.c

@@ -0,0 +1,58 @@
+/*
+ * Copyright (C) 2012 Reto Buerki
+ * Copyright (C) 2012 Adrian-Ken Rueegsegger
+ * 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 <check.h>
+
+#include "tkm_diffie_hellman.h"
+
+START_TEST(test_dh_creation)
+{
+	tkm_diffie_hellman_t *dh = NULL;
+
+	dh = tkm_diffie_hellman_create(MODP_768_BIT);
+	fail_if(dh, "MODP_768 created");
+
+	dh = tkm_diffie_hellman_create(MODP_4096_BIT);
+	fail_if(!dh, "MODP_4096 not created");
+
+	dh->dh.destroy(&dh->dh);
+}
+END_TEST
+
+START_TEST(test_dh_get_my_pubvalue)
+{
+	tkm_diffie_hellman_t *dh = tkm_diffie_hellman_create(MODP_4096_BIT);
+	fail_if(!dh, "Unable to create DH");
+
+	chunk_t value;
+	dh->dh.get_my_public_value(&dh->dh, &value);
+	dh->dh.destroy(&dh->dh);
+
+	fail_if(value.ptr == NULL, "Pubvalue is NULL");
+	fail_if(value.len != 512, "Pubvalue size mismatch");
+
+	chunk_free(&value);
+}
+END_TEST
+
+TCase *make_diffie_hellman_tests(void)
+{
+	TCase *tc = tcase_create("Diffie-Hellman tests");
+	tcase_add_test(tc, test_dh_creation);
+	tcase_add_test(tc, test_dh_get_my_pubvalue);
+
+	return tc;
+}

src/charon-tkm/tests/test_runner.c

@@ -29,6 +29,7 @@ int main(void)
 	Suite *s = suite_create("TKM tests");
 	suite_add_tcase(s, make_id_manager_tests());
 	suite_add_tcase(s, make_nonceg_tests());
+	suite_add_tcase(s, make_diffie_hellman_tests());
 
 	SRunner *sr = srunner_create(s);
 

src/charon-tkm/tests/test_runner.h

@@ -21,5 +21,6 @@
 
 TCase *make_id_manager_tests(void);
 TCase *make_nonceg_tests(void);
+TCase *make_diffie_hellman_tests(void);
 
 #endif /** TEST_RUNNER_H_ */