469 lines
16 KiB
C
469 lines
16 KiB
C
/*
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* PSA ECP layer on top of Mbed TLS crypto
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*/
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/*
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* Copyright The Mbed TLS Contributors
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* SPDX-License-Identifier: Apache-2.0
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*
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* Licensed under the Apache License, Version 2.0 (the "License"); you may
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* not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#include "common.h"
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#if defined(MBEDTLS_PSA_CRYPTO_C)
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#include <psa/crypto.h>
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#include "psa_crypto_core.h"
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#include "psa_crypto_ecp.h"
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#include "psa_crypto_random_impl.h"
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#include "psa_crypto_hash.h"
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#include <stdlib.h>
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#include <string.h>
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#include "mbedtls/platform.h"
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#include <mbedtls/ecdsa.h>
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#include <mbedtls/ecp.h>
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#include <mbedtls/error.h>
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#if defined(MBEDTLS_PSA_BUILTIN_KEY_TYPE_ECC_KEY_PAIR) || \
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defined(MBEDTLS_PSA_BUILTIN_KEY_TYPE_ECC_PUBLIC_KEY) || \
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defined(MBEDTLS_PSA_BUILTIN_ALG_ECDSA) || \
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defined(MBEDTLS_PSA_BUILTIN_ALG_DETERMINISTIC_ECDSA) || \
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defined(MBEDTLS_PSA_BUILTIN_ALG_ECDH)
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psa_status_t mbedtls_psa_ecp_load_representation(
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psa_key_type_t type, size_t curve_bits,
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const uint8_t *data, size_t data_length,
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mbedtls_ecp_keypair **p_ecp)
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{
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mbedtls_ecp_group_id grp_id = MBEDTLS_ECP_DP_NONE;
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psa_status_t status;
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mbedtls_ecp_keypair *ecp = NULL;
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size_t curve_bytes = data_length;
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int explicit_bits = (curve_bits != 0);
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if (PSA_KEY_TYPE_IS_PUBLIC_KEY(type) &&
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PSA_KEY_TYPE_ECC_GET_FAMILY(type) != PSA_ECC_FAMILY_MONTGOMERY) {
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/* A Weierstrass public key is represented as:
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* - The byte 0x04;
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* - `x_P` as a `ceiling(m/8)`-byte string, big-endian;
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* - `y_P` as a `ceiling(m/8)`-byte string, big-endian.
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* So its data length is 2m+1 where m is the curve size in bits.
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*/
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if ((data_length & 1) == 0) {
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return PSA_ERROR_INVALID_ARGUMENT;
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}
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curve_bytes = data_length / 2;
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/* Montgomery public keys are represented in compressed format, meaning
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* their curve_bytes is equal to the amount of input. */
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/* Private keys are represented in uncompressed private random integer
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* format, meaning their curve_bytes is equal to the amount of input. */
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}
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if (explicit_bits) {
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/* With an explicit bit-size, the data must have the matching length. */
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if (curve_bytes != PSA_BITS_TO_BYTES(curve_bits)) {
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return PSA_ERROR_INVALID_ARGUMENT;
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}
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} else {
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/* We need to infer the bit-size from the data. Since the only
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* information we have is the length in bytes, the value of curve_bits
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* at this stage is rounded up to the nearest multiple of 8. */
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curve_bits = PSA_BYTES_TO_BITS(curve_bytes);
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}
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/* Allocate and initialize a key representation. */
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ecp = mbedtls_calloc(1, sizeof(mbedtls_ecp_keypair));
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if (ecp == NULL) {
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return PSA_ERROR_INSUFFICIENT_MEMORY;
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}
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mbedtls_ecp_keypair_init(ecp);
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/* Load the group. */
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grp_id = mbedtls_ecc_group_of_psa(PSA_KEY_TYPE_ECC_GET_FAMILY(type),
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curve_bits, !explicit_bits);
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if (grp_id == MBEDTLS_ECP_DP_NONE) {
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/* We can't distinguish between a nonsensical family/size combination
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* (which would warrant PSA_ERROR_INVALID_ARGUMENT) and a
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* well-regarded curve that Mbed TLS just doesn't know about (which
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* would warrant PSA_ERROR_NOT_SUPPORTED). For uniformity with how
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* curves that Mbed TLS knows about but for which support is disabled
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* at build time, return NOT_SUPPORTED. */
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status = PSA_ERROR_NOT_SUPPORTED;
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goto exit;
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}
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status = mbedtls_to_psa_error(
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mbedtls_ecp_group_load(&ecp->grp, grp_id));
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if (status != PSA_SUCCESS) {
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goto exit;
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}
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/* Load the key material. */
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if (PSA_KEY_TYPE_IS_PUBLIC_KEY(type)) {
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/* Load the public value. */
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status = mbedtls_to_psa_error(
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mbedtls_ecp_point_read_binary(&ecp->grp, &ecp->Q,
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data,
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data_length));
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if (status != PSA_SUCCESS) {
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goto exit;
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}
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/* Check that the point is on the curve. */
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status = mbedtls_to_psa_error(
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mbedtls_ecp_check_pubkey(&ecp->grp, &ecp->Q));
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if (status != PSA_SUCCESS) {
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goto exit;
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}
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} else {
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/* Load and validate the secret value. */
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status = mbedtls_to_psa_error(
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mbedtls_ecp_read_key(ecp->grp.id,
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ecp,
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data,
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data_length));
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if (status != PSA_SUCCESS) {
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goto exit;
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}
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}
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*p_ecp = ecp;
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exit:
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if (status != PSA_SUCCESS) {
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mbedtls_ecp_keypair_free(ecp);
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mbedtls_free(ecp);
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}
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return status;
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}
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#endif /* defined(MBEDTLS_PSA_BUILTIN_KEY_TYPE_ECC_KEY_PAIR) ||
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* defined(MBEDTLS_PSA_BUILTIN_KEY_TYPE_ECC_PUBLIC_KEY) ||
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* defined(MBEDTLS_PSA_BUILTIN_ALG_ECDSA) ||
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* defined(MBEDTLS_PSA_BUILTIN_ALG_DETERMINISTIC_ECDSA) ||
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* defined(MBEDTLS_PSA_BUILTIN_ALG_ECDH) */
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#if defined(MBEDTLS_PSA_BUILTIN_KEY_TYPE_ECC_KEY_PAIR) || \
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defined(MBEDTLS_PSA_BUILTIN_KEY_TYPE_ECC_PUBLIC_KEY)
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psa_status_t mbedtls_psa_ecp_import_key(
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const psa_key_attributes_t *attributes,
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const uint8_t *data, size_t data_length,
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uint8_t *key_buffer, size_t key_buffer_size,
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size_t *key_buffer_length, size_t *bits)
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{
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psa_status_t status;
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mbedtls_ecp_keypair *ecp = NULL;
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/* Parse input */
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status = mbedtls_psa_ecp_load_representation(attributes->core.type,
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attributes->core.bits,
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data,
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data_length,
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&ecp);
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if (status != PSA_SUCCESS) {
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goto exit;
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}
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if (PSA_KEY_TYPE_ECC_GET_FAMILY(attributes->core.type) ==
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PSA_ECC_FAMILY_MONTGOMERY) {
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*bits = ecp->grp.nbits + 1;
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} else {
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*bits = ecp->grp.nbits;
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}
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/* Re-export the data to PSA export format. There is currently no support
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* for other input formats then the export format, so this is a 1-1
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* copy operation. */
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status = mbedtls_psa_ecp_export_key(attributes->core.type,
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ecp,
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key_buffer,
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key_buffer_size,
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key_buffer_length);
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exit:
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/* Always free the PK object (will also free contained ECP context) */
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mbedtls_ecp_keypair_free(ecp);
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mbedtls_free(ecp);
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return status;
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}
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psa_status_t mbedtls_psa_ecp_export_key(psa_key_type_t type,
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mbedtls_ecp_keypair *ecp,
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uint8_t *data,
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size_t data_size,
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size_t *data_length)
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{
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psa_status_t status;
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if (PSA_KEY_TYPE_IS_PUBLIC_KEY(type)) {
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/* Check whether the public part is loaded */
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if (mbedtls_ecp_is_zero(&ecp->Q)) {
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/* Calculate the public key */
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status = mbedtls_to_psa_error(
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mbedtls_ecp_mul(&ecp->grp, &ecp->Q, &ecp->d, &ecp->grp.G,
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mbedtls_psa_get_random,
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MBEDTLS_PSA_RANDOM_STATE));
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if (status != PSA_SUCCESS) {
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return status;
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}
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}
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status = mbedtls_to_psa_error(
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mbedtls_ecp_point_write_binary(&ecp->grp, &ecp->Q,
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MBEDTLS_ECP_PF_UNCOMPRESSED,
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data_length,
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data,
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data_size));
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if (status != PSA_SUCCESS) {
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memset(data, 0, data_size);
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}
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return status;
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} else {
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if (data_size < PSA_BITS_TO_BYTES(ecp->grp.nbits)) {
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return PSA_ERROR_BUFFER_TOO_SMALL;
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}
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status = mbedtls_to_psa_error(
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mbedtls_ecp_write_key(ecp,
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data,
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PSA_BITS_TO_BYTES(ecp->grp.nbits)));
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if (status == PSA_SUCCESS) {
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*data_length = PSA_BITS_TO_BYTES(ecp->grp.nbits);
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} else {
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memset(data, 0, data_size);
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}
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return status;
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}
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}
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psa_status_t mbedtls_psa_ecp_export_public_key(
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const psa_key_attributes_t *attributes,
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const uint8_t *key_buffer, size_t key_buffer_size,
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uint8_t *data, size_t data_size, size_t *data_length)
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{
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psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED;
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mbedtls_ecp_keypair *ecp = NULL;
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status = mbedtls_psa_ecp_load_representation(
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attributes->core.type, attributes->core.bits,
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key_buffer, key_buffer_size, &ecp);
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if (status != PSA_SUCCESS) {
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return status;
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}
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status = mbedtls_psa_ecp_export_key(
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PSA_KEY_TYPE_ECC_PUBLIC_KEY(
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PSA_KEY_TYPE_ECC_GET_FAMILY(attributes->core.type)),
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ecp, data, data_size, data_length);
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mbedtls_ecp_keypair_free(ecp);
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mbedtls_free(ecp);
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return status;
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}
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#endif /* defined(MBEDTLS_PSA_BUILTIN_KEY_TYPE_ECC_KEY_PAIR) ||
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* defined(MBEDTLS_PSA_BUILTIN_KEY_TYPE_ECC_PUBLIC_KEY) */
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#if defined(MBEDTLS_PSA_BUILTIN_KEY_TYPE_ECC_KEY_PAIR)
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psa_status_t mbedtls_psa_ecp_generate_key(
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const psa_key_attributes_t *attributes,
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uint8_t *key_buffer, size_t key_buffer_size, size_t *key_buffer_length)
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{
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psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED;
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int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
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psa_ecc_family_t curve = PSA_KEY_TYPE_ECC_GET_FAMILY(
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attributes->core.type);
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mbedtls_ecp_group_id grp_id =
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mbedtls_ecc_group_of_psa(curve, attributes->core.bits, 0);
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const mbedtls_ecp_curve_info *curve_info =
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mbedtls_ecp_curve_info_from_grp_id(grp_id);
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mbedtls_ecp_keypair ecp;
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if (attributes->domain_parameters_size != 0) {
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return PSA_ERROR_NOT_SUPPORTED;
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}
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if (grp_id == MBEDTLS_ECP_DP_NONE || curve_info == NULL) {
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return PSA_ERROR_NOT_SUPPORTED;
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}
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mbedtls_ecp_keypair_init(&ecp);
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ret = mbedtls_ecp_gen_key(grp_id, &ecp,
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mbedtls_psa_get_random,
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MBEDTLS_PSA_RANDOM_STATE);
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if (ret != 0) {
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mbedtls_ecp_keypair_free(&ecp);
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return mbedtls_to_psa_error(ret);
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}
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status = mbedtls_to_psa_error(
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mbedtls_ecp_write_key(&ecp, key_buffer, key_buffer_size));
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mbedtls_ecp_keypair_free(&ecp);
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if (status == PSA_SUCCESS) {
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*key_buffer_length = key_buffer_size;
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}
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return status;
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}
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#endif /* defined(MBEDTLS_PSA_BUILTIN_KEY_TYPE_ECC_KEY_PAIR) */
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/****************************************************************/
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/* ECDSA sign/verify */
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/****************************************************************/
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#if defined(MBEDTLS_PSA_BUILTIN_ALG_ECDSA) || \
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defined(MBEDTLS_PSA_BUILTIN_ALG_DETERMINISTIC_ECDSA)
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psa_status_t mbedtls_psa_ecdsa_sign_hash(
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const psa_key_attributes_t *attributes,
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const uint8_t *key_buffer, size_t key_buffer_size,
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psa_algorithm_t alg, const uint8_t *hash, size_t hash_length,
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uint8_t *signature, size_t signature_size, size_t *signature_length)
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{
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psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED;
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mbedtls_ecp_keypair *ecp = NULL;
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int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
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size_t curve_bytes;
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mbedtls_mpi r, s;
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status = mbedtls_psa_ecp_load_representation(attributes->core.type,
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attributes->core.bits,
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key_buffer,
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key_buffer_size,
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&ecp);
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if (status != PSA_SUCCESS) {
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return status;
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}
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curve_bytes = PSA_BITS_TO_BYTES(ecp->grp.pbits);
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mbedtls_mpi_init(&r);
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mbedtls_mpi_init(&s);
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if (signature_size < 2 * curve_bytes) {
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ret = MBEDTLS_ERR_ECP_BUFFER_TOO_SMALL;
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goto cleanup;
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}
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if (PSA_ALG_ECDSA_IS_DETERMINISTIC(alg)) {
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#if defined(MBEDTLS_PSA_BUILTIN_ALG_DETERMINISTIC_ECDSA)
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psa_algorithm_t hash_alg = PSA_ALG_SIGN_GET_HASH(alg);
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const mbedtls_md_info_t *md_info = mbedtls_md_info_from_psa(hash_alg);
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mbedtls_md_type_t md_alg = mbedtls_md_get_type(md_info);
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MBEDTLS_MPI_CHK(mbedtls_ecdsa_sign_det_ext(
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&ecp->grp, &r, &s,
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&ecp->d, hash,
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hash_length, md_alg,
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mbedtls_psa_get_random,
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MBEDTLS_PSA_RANDOM_STATE));
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#else
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ret = MBEDTLS_ERR_ECP_FEATURE_UNAVAILABLE;
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goto cleanup;
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#endif /* defined(MBEDTLS_PSA_BUILTIN_ALG_DETERMINISTIC_ECDSA) */
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} else {
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(void) alg;
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MBEDTLS_MPI_CHK(mbedtls_ecdsa_sign(&ecp->grp, &r, &s, &ecp->d,
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hash, hash_length,
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mbedtls_psa_get_random,
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MBEDTLS_PSA_RANDOM_STATE));
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}
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MBEDTLS_MPI_CHK(mbedtls_mpi_write_binary(&r,
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signature,
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curve_bytes));
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MBEDTLS_MPI_CHK(mbedtls_mpi_write_binary(&s,
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signature + curve_bytes,
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curve_bytes));
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cleanup:
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mbedtls_mpi_free(&r);
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mbedtls_mpi_free(&s);
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if (ret == 0) {
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*signature_length = 2 * curve_bytes;
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}
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mbedtls_ecp_keypair_free(ecp);
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mbedtls_free(ecp);
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return mbedtls_to_psa_error(ret);
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}
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psa_status_t mbedtls_psa_ecdsa_verify_hash(
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const psa_key_attributes_t *attributes,
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const uint8_t *key_buffer, size_t key_buffer_size,
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psa_algorithm_t alg, const uint8_t *hash, size_t hash_length,
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const uint8_t *signature, size_t signature_length)
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{
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psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED;
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mbedtls_ecp_keypair *ecp = NULL;
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int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
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size_t curve_bytes;
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mbedtls_mpi r, s;
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(void) alg;
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status = mbedtls_psa_ecp_load_representation(attributes->core.type,
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attributes->core.bits,
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key_buffer,
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key_buffer_size,
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&ecp);
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if (status != PSA_SUCCESS) {
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return status;
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}
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curve_bytes = PSA_BITS_TO_BYTES(ecp->grp.pbits);
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mbedtls_mpi_init(&r);
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mbedtls_mpi_init(&s);
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if (signature_length != 2 * curve_bytes) {
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ret = MBEDTLS_ERR_ECP_VERIFY_FAILED;
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goto cleanup;
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}
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MBEDTLS_MPI_CHK(mbedtls_mpi_read_binary(&r,
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signature,
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curve_bytes));
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MBEDTLS_MPI_CHK(mbedtls_mpi_read_binary(&s,
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signature + curve_bytes,
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curve_bytes));
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/* Check whether the public part is loaded. If not, load it. */
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if (mbedtls_ecp_is_zero(&ecp->Q)) {
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MBEDTLS_MPI_CHK(
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mbedtls_ecp_mul(&ecp->grp, &ecp->Q, &ecp->d, &ecp->grp.G,
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mbedtls_psa_get_random, MBEDTLS_PSA_RANDOM_STATE));
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}
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ret = mbedtls_ecdsa_verify(&ecp->grp, hash, hash_length,
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&ecp->Q, &r, &s);
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cleanup:
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mbedtls_mpi_free(&r);
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mbedtls_mpi_free(&s);
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mbedtls_ecp_keypair_free(ecp);
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|
mbedtls_free(ecp);
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|
|
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return mbedtls_to_psa_error(ret);
|
|
}
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#endif /* defined(MBEDTLS_PSA_BUILTIN_ALG_ECDSA) || \
|
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* defined(MBEDTLS_PSA_BUILTIN_ALG_DETERMINISTIC_ECDSA) */
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|
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#endif /* MBEDTLS_PSA_CRYPTO_C */
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