| /* |
| * PSA ECP layer on top of Mbed TLS crypto |
| */ |
| /* |
| * Copyright The Mbed TLS Contributors |
| * SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later |
| */ |
| |
| #include "common.h" |
| |
| #if defined(MBEDTLS_PSA_CRYPTO_C) |
| |
| #include <psa/crypto.h> |
| #include "psa_crypto_core.h" |
| #include "psa_crypto_ecp.h" |
| #include "psa_crypto_random_impl.h" |
| #include "mbedtls/psa_util.h" |
| |
| #include <stdlib.h> |
| #include <string.h> |
| #include "mbedtls/platform.h" |
| |
| #include <mbedtls/ecdsa.h> |
| #include <mbedtls/ecdh.h> |
| #include <mbedtls/ecp.h> |
| #include <mbedtls/error.h> |
| |
| #if defined(MBEDTLS_PSA_BUILTIN_KEY_TYPE_ECC_KEY_PAIR_BASIC) || \ |
| defined(MBEDTLS_PSA_BUILTIN_KEY_TYPE_ECC_KEY_PAIR_IMPORT) || \ |
| defined(MBEDTLS_PSA_BUILTIN_KEY_TYPE_ECC_KEY_PAIR_EXPORT) || \ |
| defined(MBEDTLS_PSA_BUILTIN_KEY_TYPE_ECC_PUBLIC_KEY) || \ |
| defined(MBEDTLS_PSA_BUILTIN_ALG_ECDSA) || \ |
| defined(MBEDTLS_PSA_BUILTIN_ALG_DETERMINISTIC_ECDSA) || \ |
| defined(MBEDTLS_PSA_BUILTIN_ALG_ECDH) |
| /* Helper function to verify if the provided EC's family and key bit size are valid. |
| * |
| * Note: "bits" parameter is used both as input and output and it might be updated |
| * in case provided input value is not multiple of 8 ("sloppy" bits). |
| */ |
| static int check_ecc_parameters(psa_ecc_family_t family, size_t *bits) |
| { |
| switch (family) { |
| case PSA_ECC_FAMILY_SECP_R1: |
| switch (*bits) { |
| case 192: |
| case 224: |
| case 256: |
| case 384: |
| case 521: |
| return PSA_SUCCESS; |
| case 528: |
| *bits = 521; |
| return PSA_SUCCESS; |
| } |
| break; |
| |
| case PSA_ECC_FAMILY_BRAINPOOL_P_R1: |
| switch (*bits) { |
| case 256: |
| case 384: |
| case 512: |
| return PSA_SUCCESS; |
| } |
| break; |
| |
| case PSA_ECC_FAMILY_MONTGOMERY: |
| switch (*bits) { |
| case 448: |
| case 255: |
| return PSA_SUCCESS; |
| case 256: |
| *bits = 255; |
| return PSA_SUCCESS; |
| } |
| break; |
| |
| case PSA_ECC_FAMILY_SECP_K1: |
| switch (*bits) { |
| case 192: |
| /* secp224k1 is not and will not be supported in PSA (#3541). */ |
| case 256: |
| return PSA_SUCCESS; |
| } |
| break; |
| } |
| |
| return PSA_ERROR_INVALID_ARGUMENT; |
| } |
| |
| psa_status_t mbedtls_psa_ecp_load_representation( |
| psa_key_type_t type, size_t curve_bits, |
| const uint8_t *data, size_t data_length, |
| mbedtls_ecp_keypair **p_ecp) |
| { |
| mbedtls_ecp_group_id grp_id = MBEDTLS_ECP_DP_NONE; |
| psa_status_t status; |
| mbedtls_ecp_keypair *ecp = NULL; |
| size_t curve_bytes = data_length; |
| int explicit_bits = (curve_bits != 0); |
| |
| if (PSA_KEY_TYPE_IS_PUBLIC_KEY(type) && |
| PSA_KEY_TYPE_ECC_GET_FAMILY(type) != PSA_ECC_FAMILY_MONTGOMERY) { |
| /* A Weierstrass public key is represented as: |
| * - The byte 0x04; |
| * - `x_P` as a `ceiling(m/8)`-byte string, big-endian; |
| * - `y_P` as a `ceiling(m/8)`-byte string, big-endian. |
| * So its data length is 2m+1 where m is the curve size in bits. |
| */ |
| if ((data_length & 1) == 0) { |
| return PSA_ERROR_INVALID_ARGUMENT; |
| } |
| curve_bytes = data_length / 2; |
| |
| /* Montgomery public keys are represented in compressed format, meaning |
| * their curve_bytes is equal to the amount of input. */ |
| |
| /* Private keys are represented in uncompressed private random integer |
| * format, meaning their curve_bytes is equal to the amount of input. */ |
| } |
| |
| if (explicit_bits) { |
| /* With an explicit bit-size, the data must have the matching length. */ |
| if (curve_bytes != PSA_BITS_TO_BYTES(curve_bits)) { |
| return PSA_ERROR_INVALID_ARGUMENT; |
| } |
| } else { |
| /* We need to infer the bit-size from the data. Since the only |
| * information we have is the length in bytes, the value of curve_bits |
| * at this stage is rounded up to the nearest multiple of 8. */ |
| curve_bits = PSA_BYTES_TO_BITS(curve_bytes); |
| } |
| |
| /* Allocate and initialize a key representation. */ |
| ecp = mbedtls_calloc(1, sizeof(mbedtls_ecp_keypair)); |
| if (ecp == NULL) { |
| return PSA_ERROR_INSUFFICIENT_MEMORY; |
| } |
| mbedtls_ecp_keypair_init(ecp); |
| |
| status = check_ecc_parameters(PSA_KEY_TYPE_ECC_GET_FAMILY(type), &curve_bits); |
| if (status != PSA_SUCCESS) { |
| goto exit; |
| } |
| |
| /* Load the group. */ |
| grp_id = mbedtls_ecc_group_from_psa(PSA_KEY_TYPE_ECC_GET_FAMILY(type), |
| curve_bits); |
| if (grp_id == MBEDTLS_ECP_DP_NONE) { |
| status = PSA_ERROR_NOT_SUPPORTED; |
| goto exit; |
| } |
| |
| status = mbedtls_to_psa_error( |
| mbedtls_ecp_group_load(&ecp->grp, grp_id)); |
| if (status != PSA_SUCCESS) { |
| goto exit; |
| } |
| |
| /* Load the key material. */ |
| if (PSA_KEY_TYPE_IS_PUBLIC_KEY(type)) { |
| /* Load the public value. */ |
| status = mbedtls_to_psa_error( |
| mbedtls_ecp_point_read_binary(&ecp->grp, &ecp->Q, |
| data, |
| data_length)); |
| if (status != PSA_SUCCESS) { |
| goto exit; |
| } |
| |
| /* Check that the point is on the curve. */ |
| status = mbedtls_to_psa_error( |
| mbedtls_ecp_check_pubkey(&ecp->grp, &ecp->Q)); |
| if (status != PSA_SUCCESS) { |
| goto exit; |
| } |
| } else { |
| /* Load and validate the secret value. */ |
| status = mbedtls_to_psa_error( |
| mbedtls_ecp_read_key(ecp->grp.id, |
| ecp, |
| data, |
| data_length)); |
| if (status != PSA_SUCCESS) { |
| goto exit; |
| } |
| } |
| |
| *p_ecp = ecp; |
| exit: |
| if (status != PSA_SUCCESS) { |
| mbedtls_ecp_keypair_free(ecp); |
| mbedtls_free(ecp); |
| } |
| |
| return status; |
| } |
| #endif /* defined(MBEDTLS_PSA_BUILTIN_KEY_TYPE_ECC_KEY_PAIR_BASIC) || |
| * defined(MBEDTLS_PSA_BUILTIN_KEY_TYPE_ECC_KEY_PAIR_IMPORT) || |
| * defined(MBEDTLS_PSA_BUILTIN_KEY_TYPE_ECC_KEY_PAIR_EXPORT) || |
| * defined(MBEDTLS_PSA_BUILTIN_KEY_TYPE_ECC_PUBLIC_KEY) || |
| * defined(MBEDTLS_PSA_BUILTIN_ALG_ECDSA) || |
| * defined(MBEDTLS_PSA_BUILTIN_ALG_DETERMINISTIC_ECDSA) || |
| * defined(MBEDTLS_PSA_BUILTIN_ALG_ECDH) */ |
| |
| #if defined(MBEDTLS_PSA_BUILTIN_KEY_TYPE_ECC_KEY_PAIR_IMPORT) || \ |
| defined(MBEDTLS_PSA_BUILTIN_KEY_TYPE_ECC_KEY_PAIR_EXPORT) || \ |
| defined(MBEDTLS_PSA_BUILTIN_KEY_TYPE_ECC_PUBLIC_KEY) |
| |
| psa_status_t mbedtls_psa_ecp_import_key( |
| const psa_key_attributes_t *attributes, |
| const uint8_t *data, size_t data_length, |
| uint8_t *key_buffer, size_t key_buffer_size, |
| size_t *key_buffer_length, size_t *bits) |
| { |
| psa_status_t status; |
| mbedtls_ecp_keypair *ecp = NULL; |
| |
| /* Parse input */ |
| status = mbedtls_psa_ecp_load_representation(attributes->type, |
| attributes->bits, |
| data, |
| data_length, |
| &ecp); |
| if (status != PSA_SUCCESS) { |
| goto exit; |
| } |
| |
| if (PSA_KEY_TYPE_ECC_GET_FAMILY(attributes->type) == |
| PSA_ECC_FAMILY_MONTGOMERY) { |
| *bits = ecp->grp.nbits + 1; |
| } else { |
| *bits = ecp->grp.nbits; |
| } |
| |
| /* Re-export the data to PSA export format. There is currently no support |
| * for other input formats then the export format, so this is a 1-1 |
| * copy operation. */ |
| status = mbedtls_psa_ecp_export_key(attributes->type, |
| ecp, |
| key_buffer, |
| key_buffer_size, |
| key_buffer_length); |
| exit: |
| /* Always free the PK object (will also free contained ECP context) */ |
| mbedtls_ecp_keypair_free(ecp); |
| mbedtls_free(ecp); |
| |
| return status; |
| } |
| |
| psa_status_t mbedtls_psa_ecp_export_key(psa_key_type_t type, |
| mbedtls_ecp_keypair *ecp, |
| uint8_t *data, |
| size_t data_size, |
| size_t *data_length) |
| { |
| psa_status_t status; |
| |
| if (PSA_KEY_TYPE_IS_PUBLIC_KEY(type)) { |
| /* Check whether the public part is loaded */ |
| if (mbedtls_ecp_is_zero(&ecp->Q)) { |
| /* Calculate the public key */ |
| status = mbedtls_to_psa_error( |
| mbedtls_ecp_mul(&ecp->grp, &ecp->Q, &ecp->d, &ecp->grp.G, |
| mbedtls_psa_get_random, |
| MBEDTLS_PSA_RANDOM_STATE)); |
| if (status != PSA_SUCCESS) { |
| return status; |
| } |
| } |
| |
| status = mbedtls_to_psa_error( |
| mbedtls_ecp_point_write_binary(&ecp->grp, &ecp->Q, |
| MBEDTLS_ECP_PF_UNCOMPRESSED, |
| data_length, |
| data, |
| data_size)); |
| if (status != PSA_SUCCESS) { |
| memset(data, 0, data_size); |
| } |
| |
| return status; |
| } else { |
| status = mbedtls_to_psa_error( |
| mbedtls_ecp_write_key_ext(ecp, data_length, data, data_size)); |
| return status; |
| } |
| } |
| |
| psa_status_t mbedtls_psa_ecp_export_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) |
| { |
| psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED; |
| mbedtls_ecp_keypair *ecp = NULL; |
| |
| status = mbedtls_psa_ecp_load_representation( |
| attributes->type, attributes->bits, |
| key_buffer, key_buffer_size, &ecp); |
| if (status != PSA_SUCCESS) { |
| return status; |
| } |
| |
| status = mbedtls_psa_ecp_export_key( |
| PSA_KEY_TYPE_ECC_PUBLIC_KEY( |
| PSA_KEY_TYPE_ECC_GET_FAMILY(attributes->type)), |
| ecp, data, data_size, data_length); |
| |
| mbedtls_ecp_keypair_free(ecp); |
| mbedtls_free(ecp); |
| |
| return status; |
| } |
| #endif /* defined(MBEDTLS_PSA_BUILTIN_KEY_TYPE_ECC_KEY_PAIR_IMPORT) || |
| * defined(MBEDTLS_PSA_BUILTIN_KEY_TYPE_ECC_KEY_PAIR_EXPORT) || |
| * defined(MBEDTLS_PSA_BUILTIN_KEY_TYPE_ECC_PUBLIC_KEY) */ |
| |
| #if defined(MBEDTLS_PSA_BUILTIN_KEY_TYPE_ECC_KEY_PAIR_GENERATE) |
| psa_status_t mbedtls_psa_ecp_generate_key( |
| const psa_key_attributes_t *attributes, |
| uint8_t *key_buffer, size_t key_buffer_size, size_t *key_buffer_length) |
| { |
| psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED; |
| int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; |
| |
| psa_ecc_family_t curve = PSA_KEY_TYPE_ECC_GET_FAMILY( |
| attributes->type); |
| mbedtls_ecp_group_id grp_id = |
| mbedtls_ecc_group_from_psa(curve, attributes->bits); |
| |
| const mbedtls_ecp_curve_info *curve_info = |
| mbedtls_ecp_curve_info_from_grp_id(grp_id); |
| mbedtls_ecp_keypair ecp; |
| |
| if (grp_id == MBEDTLS_ECP_DP_NONE || curve_info == NULL) { |
| return PSA_ERROR_NOT_SUPPORTED; |
| } |
| |
| mbedtls_ecp_keypair_init(&ecp); |
| ret = mbedtls_ecp_gen_key(grp_id, &ecp, |
| mbedtls_psa_get_random, |
| MBEDTLS_PSA_RANDOM_STATE); |
| if (ret != 0) { |
| mbedtls_ecp_keypair_free(&ecp); |
| return mbedtls_to_psa_error(ret); |
| } |
| |
| status = mbedtls_to_psa_error( |
| mbedtls_ecp_write_key_ext(&ecp, key_buffer_length, |
| key_buffer, key_buffer_size)); |
| |
| mbedtls_ecp_keypair_free(&ecp); |
| |
| return status; |
| } |
| #endif /* MBEDTLS_PSA_BUILTIN_KEY_TYPE_ECC_KEY_PAIR_GENERATE */ |
| |
| /****************************************************************/ |
| /* ECDSA sign/verify */ |
| /****************************************************************/ |
| |
| #if defined(MBEDTLS_PSA_BUILTIN_ALG_ECDSA) || \ |
| defined(MBEDTLS_PSA_BUILTIN_ALG_DETERMINISTIC_ECDSA) |
| psa_status_t mbedtls_psa_ecdsa_sign_hash( |
| const psa_key_attributes_t *attributes, |
| const uint8_t *key_buffer, size_t key_buffer_size, |
| psa_algorithm_t alg, const uint8_t *hash, size_t hash_length, |
| uint8_t *signature, size_t signature_size, size_t *signature_length) |
| { |
| psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED; |
| mbedtls_ecp_keypair *ecp = NULL; |
| int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; |
| size_t curve_bytes; |
| mbedtls_mpi r, s; |
| |
| status = mbedtls_psa_ecp_load_representation(attributes->type, |
| attributes->bits, |
| key_buffer, |
| key_buffer_size, |
| &ecp); |
| if (status != PSA_SUCCESS) { |
| return status; |
| } |
| |
| curve_bytes = PSA_BITS_TO_BYTES(ecp->grp.pbits); |
| mbedtls_mpi_init(&r); |
| mbedtls_mpi_init(&s); |
| |
| if (signature_size < 2 * curve_bytes) { |
| ret = MBEDTLS_ERR_ECP_BUFFER_TOO_SMALL; |
| goto cleanup; |
| } |
| |
| if (PSA_ALG_ECDSA_IS_DETERMINISTIC(alg)) { |
| #if defined(MBEDTLS_PSA_BUILTIN_ALG_DETERMINISTIC_ECDSA) |
| psa_algorithm_t hash_alg = PSA_ALG_SIGN_GET_HASH(alg); |
| mbedtls_md_type_t md_alg = mbedtls_md_type_from_psa_alg(hash_alg); |
| MBEDTLS_MPI_CHK(mbedtls_ecdsa_sign_det_ext( |
| &ecp->grp, &r, &s, |
| &ecp->d, hash, |
| hash_length, md_alg, |
| mbedtls_psa_get_random, |
| MBEDTLS_PSA_RANDOM_STATE)); |
| #else |
| ret = MBEDTLS_ERR_ECP_FEATURE_UNAVAILABLE; |
| goto cleanup; |
| #endif /* defined(MBEDTLS_PSA_BUILTIN_ALG_DETERMINISTIC_ECDSA) */ |
| } else { |
| (void) alg; |
| MBEDTLS_MPI_CHK(mbedtls_ecdsa_sign(&ecp->grp, &r, &s, &ecp->d, |
| hash, hash_length, |
| mbedtls_psa_get_random, |
| MBEDTLS_PSA_RANDOM_STATE)); |
| } |
| |
| MBEDTLS_MPI_CHK(mbedtls_mpi_write_binary(&r, |
| signature, |
| curve_bytes)); |
| MBEDTLS_MPI_CHK(mbedtls_mpi_write_binary(&s, |
| signature + curve_bytes, |
| curve_bytes)); |
| cleanup: |
| mbedtls_mpi_free(&r); |
| mbedtls_mpi_free(&s); |
| if (ret == 0) { |
| *signature_length = 2 * curve_bytes; |
| } |
| |
| mbedtls_ecp_keypair_free(ecp); |
| mbedtls_free(ecp); |
| |
| return mbedtls_to_psa_error(ret); |
| } |
| |
| psa_status_t mbedtls_psa_ecp_load_public_part(mbedtls_ecp_keypair *ecp) |
| { |
| int ret = 0; |
| |
| /* Check whether the public part is loaded. If not, load it. */ |
| if (mbedtls_ecp_is_zero(&ecp->Q)) { |
| ret = mbedtls_ecp_mul(&ecp->grp, &ecp->Q, |
| &ecp->d, &ecp->grp.G, |
| mbedtls_psa_get_random, |
| MBEDTLS_PSA_RANDOM_STATE); |
| } |
| |
| return mbedtls_to_psa_error(ret); |
| } |
| |
| psa_status_t mbedtls_psa_ecdsa_verify_hash( |
| const psa_key_attributes_t *attributes, |
| const uint8_t *key_buffer, size_t key_buffer_size, |
| psa_algorithm_t alg, const uint8_t *hash, size_t hash_length, |
| const uint8_t *signature, size_t signature_length) |
| { |
| psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED; |
| mbedtls_ecp_keypair *ecp = NULL; |
| size_t curve_bytes; |
| mbedtls_mpi r, s; |
| |
| (void) alg; |
| |
| status = mbedtls_psa_ecp_load_representation(attributes->type, |
| attributes->bits, |
| key_buffer, |
| key_buffer_size, |
| &ecp); |
| if (status != PSA_SUCCESS) { |
| return status; |
| } |
| |
| curve_bytes = PSA_BITS_TO_BYTES(ecp->grp.pbits); |
| mbedtls_mpi_init(&r); |
| mbedtls_mpi_init(&s); |
| |
| if (signature_length != 2 * curve_bytes) { |
| status = PSA_ERROR_INVALID_SIGNATURE; |
| goto cleanup; |
| } |
| |
| status = mbedtls_to_psa_error(mbedtls_mpi_read_binary(&r, |
| signature, |
| curve_bytes)); |
| if (status != PSA_SUCCESS) { |
| goto cleanup; |
| } |
| |
| status = mbedtls_to_psa_error(mbedtls_mpi_read_binary(&s, |
| signature + curve_bytes, |
| curve_bytes)); |
| if (status != PSA_SUCCESS) { |
| goto cleanup; |
| } |
| |
| status = mbedtls_psa_ecp_load_public_part(ecp); |
| if (status != PSA_SUCCESS) { |
| goto cleanup; |
| } |
| |
| status = mbedtls_to_psa_error(mbedtls_ecdsa_verify(&ecp->grp, hash, |
| hash_length, &ecp->Q, |
| &r, &s)); |
| cleanup: |
| mbedtls_mpi_free(&r); |
| mbedtls_mpi_free(&s); |
| mbedtls_ecp_keypair_free(ecp); |
| mbedtls_free(ecp); |
| |
| return status; |
| } |
| |
| #endif /* defined(MBEDTLS_PSA_BUILTIN_ALG_ECDSA) || \ |
| * defined(MBEDTLS_PSA_BUILTIN_ALG_DETERMINISTIC_ECDSA) */ |
| |
| /****************************************************************/ |
| /* ECDH Key Agreement */ |
| /****************************************************************/ |
| |
| #if defined(MBEDTLS_PSA_BUILTIN_ALG_ECDH) |
| psa_status_t mbedtls_psa_key_agreement_ecdh( |
| const psa_key_attributes_t *attributes, |
| const uint8_t *key_buffer, size_t key_buffer_size, |
| psa_algorithm_t alg, const uint8_t *peer_key, size_t peer_key_length, |
| uint8_t *shared_secret, size_t shared_secret_size, |
| size_t *shared_secret_length) |
| { |
| psa_status_t status; |
| if (!PSA_KEY_TYPE_IS_ECC_KEY_PAIR(attributes->type) || |
| !PSA_ALG_IS_ECDH(alg)) { |
| return PSA_ERROR_INVALID_ARGUMENT; |
| } |
| mbedtls_ecp_keypair *ecp = NULL; |
| status = mbedtls_psa_ecp_load_representation( |
| attributes->type, |
| attributes->bits, |
| key_buffer, |
| key_buffer_size, |
| &ecp); |
| if (status != PSA_SUCCESS) { |
| return status; |
| } |
| mbedtls_ecp_keypair *their_key = NULL; |
| mbedtls_ecdh_context ecdh; |
| size_t bits = 0; |
| psa_ecc_family_t curve = mbedtls_ecc_group_to_psa(ecp->grp.id, &bits); |
| mbedtls_ecdh_init(&ecdh); |
| |
| status = mbedtls_psa_ecp_load_representation( |
| PSA_KEY_TYPE_ECC_PUBLIC_KEY(curve), |
| bits, |
| peer_key, |
| peer_key_length, |
| &their_key); |
| if (status != PSA_SUCCESS) { |
| goto exit; |
| } |
| |
| status = mbedtls_to_psa_error( |
| mbedtls_ecdh_get_params(&ecdh, their_key, MBEDTLS_ECDH_THEIRS)); |
| if (status != PSA_SUCCESS) { |
| goto exit; |
| } |
| status = mbedtls_to_psa_error( |
| mbedtls_ecdh_get_params(&ecdh, ecp, MBEDTLS_ECDH_OURS)); |
| if (status != PSA_SUCCESS) { |
| goto exit; |
| } |
| |
| status = mbedtls_to_psa_error( |
| mbedtls_ecdh_calc_secret(&ecdh, |
| shared_secret_length, |
| shared_secret, shared_secret_size, |
| mbedtls_psa_get_random, |
| MBEDTLS_PSA_RANDOM_STATE)); |
| if (status != PSA_SUCCESS) { |
| goto exit; |
| } |
| if (PSA_BITS_TO_BYTES(bits) != *shared_secret_length) { |
| status = PSA_ERROR_CORRUPTION_DETECTED; |
| } |
| exit: |
| if (status != PSA_SUCCESS) { |
| mbedtls_platform_zeroize(shared_secret, shared_secret_size); |
| } |
| mbedtls_ecdh_free(&ecdh); |
| mbedtls_ecp_keypair_free(their_key); |
| mbedtls_free(their_key); |
| mbedtls_ecp_keypair_free(ecp); |
| mbedtls_free(ecp); |
| return status; |
| } |
| #endif /* MBEDTLS_PSA_BUILTIN_ALG_ECDH */ |
| |
| |
| #endif /* MBEDTLS_PSA_CRYPTO_C */ |
