src/libstrongswan/plugins/wolfssl/wolfssl_ec_diffie_hellman.c - manifest_repos/strongswan - Git at Google

 /*
  * Copyright (C) 2019 Sean Parkinson, wolfSSL Inc.
  *
  * Permission is hereby granted, free of charge, to any person obtaining a copy
  * of this software and associated documentation files (the "Software"), to deal
  * in the Software without restriction, including without limitation the rights
  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  * copies of the Software, and to permit persons to whom the Software is
  * furnished to do so, subject to the following conditions:
  *
  * The above copyright notice and this permission notice shall be included in
  * all copies or substantial portions of the Software.
  *
  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  * THE SOFTWARE.
  */

 #include "wolfssl_common.h"

 #ifdef HAVE_ECC_DHE

 #include <wolfssl/wolfcrypt/ecc.h>

 #include "wolfssl_ec_diffie_hellman.h"
 #include "wolfssl_util.h"

 #include <utils/debug.h>

 typedef struct private_wolfssl_ec_diffie_hellman_t private_wolfssl_ec_diffie_hellman_t;

 /**
  * Private data of an wolfssl_ec_diffie_hellman_t object.
  */
 struct private_wolfssl_ec_diffie_hellman_t {
 	/**
 	 * Public wolfssl_ec_diffie_hellman_t interface.
 	 */
 	wolfssl_ec_diffie_hellman_t public;

 	/**
 	 * Diffie Hellman group number.
 	 */
 	diffie_hellman_group_t group;

 	/**
 	 * EC curve id for creating keys
 	 */
 	ecc_curve_id curve_id;

 	/**
 	 * Size of an ordinate in bytes
 	 */
 	int keysize;

 	/**
 	 * EC private (public) key
 	 */
 	ecc_key key;

 	/**
 	 * Shared secret
 	 */
 	chunk_t shared_secret;
 };

 /**
  * Convert a chunk to an ecc_point (which must already exist). The x and y
  * coordinates of the point have to be concatenated in the chunk.
  */
 static bool chunk2ecp(chunk_t chunk, ecc_point *point)
 {
 	if (!wolfssl_mp_split(chunk, point->x, point->y))
 	{
 		return FALSE;
 	}
 	if (mp_set(point->z, 1) != 0)
 	{
 		return FALSE;
 	}
 	return TRUE;
 }

 /**
  * Convert an ec_point to a chunk by concatenating the x and y coordinates of
  * the point. This function allocates memory for the chunk.
  */
 static bool ecp2chunk(int keysize, ecc_point *point, chunk_t *chunk,
 					  bool x_coordinate_only)
 {
 	mp_int *y = NULL;

 	if (!x_coordinate_only)
 	{
 		keysize *= 2;
 		y = point->y;
 	}
 	return wolfssl_mp_cat(keysize, point->x, y, chunk);
 }

 /**
  * Perform the elliptic curve scalar multiplication.
  */
 static bool wolfssl_ecc_multiply(const ecc_set_type *ecc_set, mp_int *scalar,
 								 ecc_point *point, ecc_point *r)
 {
 	mp_int a, prime;
 	int ret;

 	if (mp_init(&a) != 0)
 	{
 		return FALSE;
 	}
 	if (mp_init(&prime) != 0)
 	{
 		mp_free(&a);
 		return FALSE;
 	}

 	ret = mp_read_radix(&a, ecc_set->Af, MP_RADIX_HEX);
 	if (ret == 0)
 	{
 		ret = mp_read_radix(&prime, ecc_set->prime, MP_RADIX_HEX);
 	}
 	if (ret == 0)
 	{
 		/* multiply the point by our secret */
 		ret = wc_ecc_mulmod(scalar, point, r, &a, &prime, 1);
 	}

 	mp_free(&prime);
 	mp_free(&a);

 	return ret == 0;
 }

 /**
  * Compute the shared secret.
  *
  * We cannot use the function wc_ecc_shared_secret() because that returns only
  * the x coordinate of the shared secret point (which is defined, for instance,
  * in 'NIST SP 800-56A').
  * However, we need both coordinates as RFC 4753 says: "The Diffie-Hellman
  *   public value is obtained by concatenating the x and y values. The format
  *   of the Diffie-Hellman shared secret value is the same as that of the
  *   Diffie-Hellman public value."
  */
 static bool compute_shared_key(private_wolfssl_ec_diffie_hellman_t *this,
 							   ecc_point *pub_key, chunk_t *shared_secret)
 {
 	ecc_point* secret;
 	bool success = FALSE;

 	if ((secret = wc_ecc_new_point()) == NULL)
 	{
 		return FALSE;
 	}

 	if (wolfssl_ecc_multiply(this->key.dp, &this->key.k, pub_key, secret))
 	{
 		success = ecp2chunk(this->keysize, secret, shared_secret, TRUE);
 	}

 	wc_ecc_del_point(secret);
 	return success;
 }

 METHOD(diffie_hellman_t, set_other_public_value, bool,
 	private_wolfssl_ec_diffie_hellman_t *this, chunk_t value)
 {
 	ecc_point *pub_key;

 	if (!diffie_hellman_verify_value(this->group, value))
 	{
 		return FALSE;
 	}

 	if ((pub_key = wc_ecc_new_point()) == NULL)
 	{
 		return FALSE;
 	}

 	if (!chunk2ecp(value, pub_key))
 	{
 		DBG1(DBG_LIB, "ECDH public value is malformed");
 		wc_ecc_del_point(pub_key);
 		return FALSE;
 	}

 	chunk_clear(&this->shared_secret);

 	if (!compute_shared_key(this, pub_key, &this->shared_secret))
 	{
 		DBG1(DBG_LIB, "ECDH shared secret computation failed");
 		chunk_clear(&this->shared_secret);
 		wc_ecc_del_point(pub_key);
 		return FALSE;
 	}
 	wc_ecc_del_point(pub_key);
 	return TRUE;
 }

 METHOD(diffie_hellman_t, get_my_public_value, bool,
 	private_wolfssl_ec_diffie_hellman_t *this,chunk_t *value)
 {
 	return ecp2chunk(this->keysize, &this->key.pubkey, value, FALSE);
 }

 METHOD(diffie_hellman_t, set_private_value, bool,
 	private_wolfssl_ec_diffie_hellman_t *this, chunk_t value)
 {
 	bool success = FALSE;
 	ecc_point *base;
 	int ret;

 	if ((base = wc_ecc_new_point()) == NULL)
 	{
 		return FALSE;
 	}

 	ret = mp_read_unsigned_bin(&this->key.k, value.ptr, value.len);
 	/* get base point */
 	if (ret == 0)
 	{
 		ret = mp_read_radix(base->x, this->key.dp->Gx, MP_RADIX_HEX);
 	}
 	if (ret == 0)
 	{
 		ret = mp_read_radix(base->y, this->key.dp->Gy, MP_RADIX_HEX);
 	}
 	if (ret == 0)
 	{
 		ret = mp_set(base->z, 1);
 	}
 	if (ret == 0)
 	{
 		/* calculate public key */
 		success = wolfssl_ecc_multiply(this->key.dp, &this->key.k, base,
 									   &this->key.pubkey);
 	}

 	wc_ecc_del_point(base);

 	return success;
 }

 METHOD(diffie_hellman_t, get_shared_secret, bool,
 	private_wolfssl_ec_diffie_hellman_t *this, chunk_t *secret)
 {
 	if (!this->shared_secret.len)
 	{
 		return FALSE;
 	}
 	*secret = chunk_clone(this->shared_secret);
 	return TRUE;
 }

 METHOD(diffie_hellman_t, get_dh_group, diffie_hellman_group_t,
 	private_wolfssl_ec_diffie_hellman_t *this)
 {
 	return this->group;
 }

 METHOD(diffie_hellman_t, destroy, void,
 	private_wolfssl_ec_diffie_hellman_t *this)
 {
 	wc_ecc_free(&this->key);
 	chunk_clear(&this->shared_secret);
 	free(this);
 }

 /*
  * Described in header
  */
 wolfssl_ec_diffie_hellman_t *wolfssl_ec_diffie_hellman_create(diffie_hellman_group_t group)
 {
 	private_wolfssl_ec_diffie_hellman_t *this;
 	WC_RNG rng;

 	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,
 				.set_private_value = _set_private_value,
 				.get_dh_group = _get_dh_group,
 				.destroy = _destroy,
 			},
 		},
 		.group = group,
 	);

 	if (wc_ecc_init(&this->key) != 0)
 	{
 		DBG1(DBG_LIB, "key init failed, ecdh create failed");
 		free(this);
 		return NULL;
 	}

 	switch (group)
 	{
 		case ECP_192_BIT:
 			this->curve_id = ECC_SECP192R1;
 			this->keysize = 192 / 8;
 			break;
 		case ECP_224_BIT:
 			this->curve_id = ECC_SECP224R1;
 			this->keysize = 224 / 8;
 			break;
 		case ECP_256_BIT:
 			this->curve_id = ECC_SECP256R1;
 			this->keysize = 256 / 8;
 			break;
 		case ECP_384_BIT:
 			this->curve_id = ECC_SECP384R1;
 			this->keysize = 384 / 8;
 			break;
 		case ECP_521_BIT:
 			this->curve_id = ECC_SECP521R1;
 			this->keysize = (521 + 7) / 8;
 			break;
 #ifdef HAVE_ECC_BRAINPOOL
 		case ECP_224_BP:
 			this->curve_id = ECC_BRAINPOOLP224R1;
 			this->keysize = 224 / 8;
 			break;
 		case ECP_256_BP:
 			this->curve_id = ECC_BRAINPOOLP256R1;
 			this->keysize = 256 / 8;
 			break;
 		case ECP_384_BP:
 			this->curve_id = ECC_BRAINPOOLP384R1;
 			this->keysize = 384 / 8;
 			break;
 		case ECP_512_BP:
 			this->curve_id = ECC_BRAINPOOLP512R1;
 			this->keysize = 512 / 8;
 			break;
 #endif
 		default:
 			destroy(this);
 			return NULL;
 	}

 	if (wc_InitRng(&rng) != 0)
 	{
 		DBG1(DBG_LIB, "RNG init failed, ecdh create failed");
 		destroy(this);
 		return NULL;
 	}

 	/* generate an EC private (public) key */
 	if (wc_ecc_make_key_ex(&rng, this->keysize, &this->key,
 						   this->curve_id) != 0)
 	{
 		DBG1(DBG_LIB, "make key failed, wolfssl ECDH create failed");
 		destroy(this);
 		return NULL;
 	}
 	wc_FreeRng(&rng);

 	return &this->public;
 }
 #endif /* HAVE_ECC_DHE */
	/*
	* Copyright (C) 2019 Sean Parkinson, wolfSSL Inc.
	*
	* Permission is hereby granted, free of charge, to any person obtaining a copy
	* of this software and associated documentation files (the "Software"), to deal
	* in the Software without restriction, including without limitation the rights
	* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
	* copies of the Software, and to permit persons to whom the Software is
	* furnished to do so, subject to the following conditions:
	*
	* The above copyright notice and this permission notice shall be included in
	* all copies or substantial portions of the Software.
	*
	* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
	* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
	* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
	* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
	* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
	* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
	* THE SOFTWARE.
	*/

	#include "wolfssl_common.h"

	#ifdef HAVE_ECC_DHE

	#include <wolfssl/wolfcrypt/ecc.h>

	#include "wolfssl_ec_diffie_hellman.h"
	#include "wolfssl_util.h"

	#include <utils/debug.h>

	typedef struct private_wolfssl_ec_diffie_hellman_t private_wolfssl_ec_diffie_hellman_t;

	/**
	* Private data of an wolfssl_ec_diffie_hellman_t object.
	*/
	struct private_wolfssl_ec_diffie_hellman_t {
	/**
	* Public wolfssl_ec_diffie_hellman_t interface.
	*/
	wolfssl_ec_diffie_hellman_t public;

	/**
	* Diffie Hellman group number.
	*/
	diffie_hellman_group_t group;

	/**
	* EC curve id for creating keys
	*/
	ecc_curve_id curve_id;

	/**
	* Size of an ordinate in bytes
	*/
	int keysize;

	/**
	* EC private (public) key
	*/
	ecc_key key;

	/**
	* Shared secret
	*/
	chunk_t shared_secret;
	};

	/**
	* Convert a chunk to an ecc_point (which must already exist). The x and y
	* coordinates of the point have to be concatenated in the chunk.
	*/
	static bool chunk2ecp(chunk_t chunk, ecc_point *point)
	{
	if (!wolfssl_mp_split(chunk, point->x, point->y))
	{
	return FALSE;
	}
	if (mp_set(point->z, 1) != 0)
	{
	return FALSE;
	}
	return TRUE;
	}

	/**
	* Convert an ec_point to a chunk by concatenating the x and y coordinates of
	* the point. This function allocates memory for the chunk.
	*/
	static bool ecp2chunk(int keysize, ecc_point point, chunk_t chunk,
	bool x_coordinate_only)
	{
	mp_int *y = NULL;

	if (!x_coordinate_only)
	{
	keysize *= 2;
	y = point->y;
	}
	return wolfssl_mp_cat(keysize, point->x, y, chunk);
	}

	/**
	* Perform the elliptic curve scalar multiplication.
	*/
	static bool wolfssl_ecc_multiply(const ecc_set_type ecc_set, mp_int scalar,
	ecc_point point, ecc_point r)
	{
	mp_int a, prime;
	int ret;

	if (mp_init(&a) != 0)
	{
	return FALSE;
	}
	if (mp_init(&prime) != 0)
	{
	mp_free(&a);
	return FALSE;
	}

	ret = mp_read_radix(&a, ecc_set->Af, MP_RADIX_HEX);
	if (ret == 0)
	{
	ret = mp_read_radix(&prime, ecc_set->prime, MP_RADIX_HEX);
	}
	if (ret == 0)
	{
	/* multiply the point by our secret */
	ret = wc_ecc_mulmod(scalar, point, r, &a, &prime, 1);
	}

	mp_free(&prime);
	mp_free(&a);

	return ret == 0;
	}

	/**
	* Compute the shared secret.
	*
	* We cannot use the function wc_ecc_shared_secret() because that returns only
	* the x coordinate of the shared secret point (which is defined, for instance,
	* in 'NIST SP 800-56A').
	* However, we need both coordinates as RFC 4753 says: "The Diffie-Hellman
	* public value is obtained by concatenating the x and y values. The format
	* of the Diffie-Hellman shared secret value is the same as that of the
	* Diffie-Hellman public value."
	*/
	static bool compute_shared_key(private_wolfssl_ec_diffie_hellman_t *this,
	ecc_point pub_key, chunk_t shared_secret)
	{
	ecc_point* secret;
	bool success = FALSE;

	if ((secret = wc_ecc_new_point()) == NULL)
	{
	return FALSE;
	}

	if (wolfssl_ecc_multiply(this->key.dp, &this->key.k, pub_key, secret))
	{
	success = ecp2chunk(this->keysize, secret, shared_secret, TRUE);
	}

	wc_ecc_del_point(secret);
	return success;
	}

	METHOD(diffie_hellman_t, set_other_public_value, bool,
	private_wolfssl_ec_diffie_hellman_t *this, chunk_t value)
	{
	ecc_point *pub_key;

	if (!diffie_hellman_verify_value(this->group, value))
	{
	return FALSE;
	}

	if ((pub_key = wc_ecc_new_point()) == NULL)
	{
	return FALSE;
	}

	if (!chunk2ecp(value, pub_key))
	{
	DBG1(DBG_LIB, "ECDH public value is malformed");
	wc_ecc_del_point(pub_key);
	return FALSE;
	}

	chunk_clear(&this->shared_secret);

	if (!compute_shared_key(this, pub_key, &this->shared_secret))
	{
	DBG1(DBG_LIB, "ECDH shared secret computation failed");
	chunk_clear(&this->shared_secret);
	wc_ecc_del_point(pub_key);
	return FALSE;
	}
	wc_ecc_del_point(pub_key);
	return TRUE;
	}

	METHOD(diffie_hellman_t, get_my_public_value, bool,
	private_wolfssl_ec_diffie_hellman_t this,chunk_t value)
	{
	return ecp2chunk(this->keysize, &this->key.pubkey, value, FALSE);
	}

	METHOD(diffie_hellman_t, set_private_value, bool,
	private_wolfssl_ec_diffie_hellman_t *this, chunk_t value)
	{
	bool success = FALSE;
	ecc_point *base;
	int ret;

	if ((base = wc_ecc_new_point()) == NULL)
	{
	return FALSE;
	}

	ret = mp_read_unsigned_bin(&this->key.k, value.ptr, value.len);
	/* get base point */
	if (ret == 0)
	{
	ret = mp_read_radix(base->x, this->key.dp->Gx, MP_RADIX_HEX);
	}
	if (ret == 0)
	{
	ret = mp_read_radix(base->y, this->key.dp->Gy, MP_RADIX_HEX);
	}
	if (ret == 0)
	{
	ret = mp_set(base->z, 1);
	}
	if (ret == 0)
	{
	/* calculate public key */
	success = wolfssl_ecc_multiply(this->key.dp, &this->key.k, base,
	&this->key.pubkey);
	}

	wc_ecc_del_point(base);

	return success;
	}

	METHOD(diffie_hellman_t, get_shared_secret, bool,
	private_wolfssl_ec_diffie_hellman_t this, chunk_t secret)
	{
	if (!this->shared_secret.len)
	{
	return FALSE;
	}
	*secret = chunk_clone(this->shared_secret);
	return TRUE;
	}

	METHOD(diffie_hellman_t, get_dh_group, diffie_hellman_group_t,
	private_wolfssl_ec_diffie_hellman_t *this)
	{
	return this->group;
	}

	METHOD(diffie_hellman_t, destroy, void,
	private_wolfssl_ec_diffie_hellman_t *this)
	{
	wc_ecc_free(&this->key);
	chunk_clear(&this->shared_secret);
	free(this);
	}

	/*
	* Described in header
	*/
	wolfssl_ec_diffie_hellman_t *wolfssl_ec_diffie_hellman_create(diffie_hellman_group_t group)
	{
	private_wolfssl_ec_diffie_hellman_t *this;
	WC_RNG rng;

	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,
	.set_private_value = _set_private_value,
	.get_dh_group = _get_dh_group,
	.destroy = _destroy,
	},
	},
	.group = group,
	);

	if (wc_ecc_init(&this->key) != 0)
	{
	DBG1(DBG_LIB, "key init failed, ecdh create failed");
	free(this);
	return NULL;
	}

	switch (group)
	{
	case ECP_192_BIT:
	this->curve_id = ECC_SECP192R1;
	this->keysize = 192 / 8;
	break;
	case ECP_224_BIT:
	this->curve_id = ECC_SECP224R1;
	this->keysize = 224 / 8;
	break;
	case ECP_256_BIT:
	this->curve_id = ECC_SECP256R1;
	this->keysize = 256 / 8;
	break;
	case ECP_384_BIT:
	this->curve_id = ECC_SECP384R1;
	this->keysize = 384 / 8;
	break;
	case ECP_521_BIT:
	this->curve_id = ECC_SECP521R1;
	this->keysize = (521 + 7) / 8;
	break;
	#ifdef HAVE_ECC_BRAINPOOL
	case ECP_224_BP:
	this->curve_id = ECC_BRAINPOOLP224R1;
	this->keysize = 224 / 8;
	break;
	case ECP_256_BP:
	this->curve_id = ECC_BRAINPOOLP256R1;
	this->keysize = 256 / 8;
	break;
	case ECP_384_BP:
	this->curve_id = ECC_BRAINPOOLP384R1;
	this->keysize = 384 / 8;
	break;
	case ECP_512_BP:
	this->curve_id = ECC_BRAINPOOLP512R1;
	this->keysize = 512 / 8;
	break;
	#endif
	default:
	destroy(this);
	return NULL;
	}

	if (wc_InitRng(&rng) != 0)
	{
	DBG1(DBG_LIB, "RNG init failed, ecdh create failed");
	destroy(this);
	return NULL;
	}

	/* generate an EC private (public) key */
	if (wc_ecc_make_key_ex(&rng, this->keysize, &this->key,
	this->curve_id) != 0)
	{
	DBG1(DBG_LIB, "make key failed, wolfssl ECDH create failed");
	destroy(this);
	return NULL;
	}
	wc_FreeRng(&rng);

	return &this->public;
	}
	#endif /* HAVE_ECC_DHE */