mbedtls/library/psa_crypto_ffdh.c
Przemek Stekiel a9ca13136c Move check of the key type to mbedtls_psa_key_agreement_ffdh
Signed-off-by: Przemek Stekiel <przemyslaw.stekiel@mobica.com>
2023-04-26 09:07:20 +02:00

245 lines
7.9 KiB
C

/*
* PSA FFDH layer on top of Mbed TLS crypto
*/
/*
* Copyright The Mbed TLS Contributors
* SPDX-License-Identifier: Apache-2.0
*
* Licensed under the Apache License, Version 2.0 (the "License"); you may
* not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include "common.h"
#if defined(MBEDTLS_PSA_CRYPTO_C)
#include <psa/crypto.h>
#include "psa_crypto_core.h"
#include "psa_crypto_ffdh.h"
#include "psa_crypto_random_impl.h"
#if defined(MBEDTLS_PSA_BUILTIN_KEY_TYPE_FFDH_KEY_PAIR) || \
defined(MBEDTLS_PSA_BUILTIN_KEY_TYPE_FFDH_PUBLIC_KEY)
static psa_status_t mbedtls_psa_ffdh_set_prime_generator(size_t key_size,
mbedtls_mpi *P,
mbedtls_mpi *G)
{
const unsigned char *dhm_P = NULL;
const unsigned char *dhm_G = NULL;
size_t dhm_size_P = 0;
size_t dhm_size_G = 0;
int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
if (P == NULL && G == NULL) {
return PSA_ERROR_INVALID_ARGUMENT;
}
static const unsigned char dhm_P_2048[] =
MBEDTLS_DHM_RFC7919_FFDHE2048_P_BIN;
static const unsigned char dhm_P_3072[] =
MBEDTLS_DHM_RFC7919_FFDHE3072_P_BIN;
static const unsigned char dhm_P_4096[] =
MBEDTLS_DHM_RFC7919_FFDHE4096_P_BIN;
static const unsigned char dhm_P_6144[] =
MBEDTLS_DHM_RFC7919_FFDHE6144_P_BIN;
static const unsigned char dhm_P_8192[] =
MBEDTLS_DHM_RFC7919_FFDHE8192_P_BIN;
static const unsigned char dhm_G_2048[] =
MBEDTLS_DHM_RFC7919_FFDHE2048_G_BIN;
static const unsigned char dhm_G_3072[] =
MBEDTLS_DHM_RFC7919_FFDHE3072_G_BIN;
static const unsigned char dhm_G_4096[] =
MBEDTLS_DHM_RFC7919_FFDHE4096_G_BIN;
static const unsigned char dhm_G_6144[] =
MBEDTLS_DHM_RFC7919_FFDHE6144_G_BIN;
static const unsigned char dhm_G_8192[] =
MBEDTLS_DHM_RFC7919_FFDHE8192_G_BIN;
if (key_size <= 256) {
dhm_P = dhm_P_2048;
dhm_G = dhm_G_2048;
dhm_size_P = sizeof(dhm_P_2048);
dhm_size_G = sizeof(dhm_G_2048);
} else if (key_size <= 384) {
dhm_P = dhm_P_3072;
dhm_G = dhm_G_3072;
dhm_size_P = sizeof(dhm_P_3072);
dhm_size_G = sizeof(dhm_G_3072);
} else if (key_size <= 512) {
dhm_P = dhm_P_4096;
dhm_G = dhm_G_4096;
dhm_size_P = sizeof(dhm_P_4096);
dhm_size_G = sizeof(dhm_G_4096);
} else if (key_size <= 768) {
dhm_P = dhm_P_6144;
dhm_G = dhm_G_6144;
dhm_size_P = sizeof(dhm_P_6144);
dhm_size_G = sizeof(dhm_G_6144);
} else if (key_size <= 1024) {
dhm_P = dhm_P_8192;
dhm_G = dhm_G_8192;
dhm_size_P = sizeof(dhm_P_8192);
dhm_size_G = sizeof(dhm_G_8192);
} else {
return PSA_ERROR_INVALID_ARGUMENT;
}
if (P != NULL) {
MBEDTLS_MPI_CHK(mbedtls_mpi_read_binary(P, dhm_P,
dhm_size_P));
}
if (G != NULL) {
MBEDTLS_MPI_CHK(mbedtls_mpi_read_binary(G, dhm_G,
dhm_size_G));
}
cleanup:
if (ret != 0) {
return mbedtls_to_psa_error(ret);
}
return PSA_SUCCESS;
}
#if defined(MBEDTLS_PSA_BUILTIN_ALG_FFDH)
psa_status_t mbedtls_psa_key_agreement_ffdh(
const psa_key_attributes_t *attributes,
const uint8_t *peer_key,
size_t peer_key_length,
const uint8_t *key_buffer,
size_t key_buffer_size,
uint8_t *shared_secret,
size_t shared_secret_size,
size_t *shared_secret_length)
{
int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED;
mbedtls_mpi P, G, X, GY, K;
const size_t calculated_shared_secret_size = peer_key_length;
if (peer_key_length != key_buffer_size ||
calculated_shared_secret_size > shared_secret_size) {
return PSA_ERROR_INVALID_ARGUMENT;
}
if (!PSA_KEY_TYPE_IS_DH_KEY_PAIR(psa_get_key_type(attributes))) {
return PSA_ERROR_INVALID_ARGUMENT;
}
mbedtls_mpi_init(&P); mbedtls_mpi_init(&G);
mbedtls_mpi_init(&X); mbedtls_mpi_init(&GY);
mbedtls_mpi_init(&K);
status = mbedtls_psa_ffdh_set_prime_generator(
PSA_BITS_TO_BYTES(attributes->core.bits), &P, &G);
if (status == PSA_SUCCESS) {
MBEDTLS_MPI_CHK(mbedtls_mpi_read_binary(&X, key_buffer,
key_buffer_size));
MBEDTLS_MPI_CHK(mbedtls_mpi_read_binary(&GY, peer_key,
peer_key_length));
/* Calculate shared secret public key: K = G^(XY) mod P */
MBEDTLS_MPI_CHK(mbedtls_mpi_exp_mod(&K, &GY, &X, &P, NULL));
MBEDTLS_MPI_CHK(mbedtls_mpi_write_binary(&K, shared_secret,
calculated_shared_secret_size));
*shared_secret_length = calculated_shared_secret_size;
}
cleanup:
mbedtls_mpi_free(&P); mbedtls_mpi_free(&G);
mbedtls_mpi_free(&X); mbedtls_mpi_free(&GY);
mbedtls_mpi_free(&K);
if (status == PSA_SUCCESS && ret != 0) {
return mbedtls_to_psa_error(ret);
}
return PSA_SUCCESS;
}
#endif /* MBEDTLS_PSA_BUILTIN_ALG_FFDH */
psa_status_t mbedtls_psa_export_ffdh_public_key(
const psa_key_attributes_t *attributes,
const uint8_t *key_buffer,
size_t key_buffer_size,
uint8_t *data,
size_t data_size,
size_t *data_length)
{
int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED;
mbedtls_mpi GX, G, X, P;
mbedtls_mpi_init(&GX); mbedtls_mpi_init(&G);
mbedtls_mpi_init(&X); mbedtls_mpi_init(&P);
status = mbedtls_psa_ffdh_set_prime_generator(
PSA_BITS_TO_BYTES(attributes->core.bits), &P, &G);
if (status == PSA_SUCCESS) {
MBEDTLS_MPI_CHK(mbedtls_mpi_read_binary(&X, key_buffer,
key_buffer_size));
MBEDTLS_MPI_CHK(mbedtls_mpi_exp_mod(&GX, &G, &X, &P, NULL));
MBEDTLS_MPI_CHK(mbedtls_mpi_write_binary(&GX, data, data_size));
*data_length = mbedtls_mpi_size(&GX);
}
cleanup:
mbedtls_mpi_free(&P); mbedtls_mpi_free(&G);
mbedtls_mpi_free(&X); mbedtls_mpi_free(&GX);
if (status == PSA_SUCCESS && ret != 0) {
return mbedtls_to_psa_error(ret);
}
return status;
}
psa_status_t mbedtls_psa_ffdh_generate_key(
const psa_key_attributes_t *attributes,
uint8_t *key_buffer, size_t key_buffer_size, size_t *key_buffer_length)
{
mbedtls_mpi X, P;
int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED;
mbedtls_mpi_init(&P); mbedtls_mpi_init(&X);
status = mbedtls_psa_ffdh_set_prime_generator(
PSA_BITS_TO_BYTES(attributes->core.bits), &P, NULL);
if (status == PSA_SUCCESS) {
MBEDTLS_MPI_CHK(mbedtls_mpi_random(&X, 4, &P, mbedtls_psa_get_random,
MBEDTLS_PSA_RANDOM_STATE));
MBEDTLS_MPI_CHK(mbedtls_mpi_sub_int(&X, &X, 2));
*key_buffer_length = mbedtls_mpi_size(&X);
MBEDTLS_MPI_CHK(mbedtls_mpi_write_binary(&X, key_buffer,
key_buffer_size));
}
cleanup:
mbedtls_mpi_free(&P); mbedtls_mpi_free(&X);
if (status == PSA_SUCCESS && ret != 0) {
return mbedtls_to_psa_error(ret);
}
return status;
}
#endif /* MBEDTLS_PSA_BUILTIN_KEY_TYPE_FFDH_KEY_PAIR ||
MBEDTLS_PSA_BUILTIN_KEY_TYPE_FFDH_PUBLIC_KEY */
#endif /* MBEDTLS_PSA_CRYPTO_C */