/* * PSA ECP 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 #include "psa_crypto_core.h" #include "psa_crypto_ecp.h" #include "psa_crypto_random_impl.h" #include #include #include "mbedtls/platform.h" #if !defined(MBEDTLS_PLATFORM_C) #define mbedtls_calloc calloc #define mbedtls_free free #endif #include #include #include #if ( defined(MBEDTLS_PSA_BUILTIN_KEY_TYPE_ECC_KEY_PAIR) || \ ( defined(PSA_CRYPTO_DRIVER_TEST) && \ defined(MBEDTLS_PSA_ACCEL_KEY_TYPE_ECC_KEY_PAIR) ) ) #define BUILTIN_KEY_TYPE_ECC_KEY_PAIR 1 #endif #if ( defined(MBEDTLS_PSA_BUILTIN_KEY_TYPE_ECC_PUBLIC_KEY) || \ ( defined(PSA_CRYPTO_DRIVER_TEST) && \ defined(MBEDTLS_PSA_ACCEL_KEY_TYPE_ECC_PUBLIC_KEY) ) ) #define BUILTIN_KEY_TYPE_ECC_PUBLIC_KEY 1 #endif #if ( defined(MBEDTLS_PSA_BUILTIN_ALG_ECDSA) || \ ( defined(PSA_CRYPTO_DRIVER_TEST) && \ defined(MBEDTLS_PSA_ACCEL_ALG_ECDSA) && \ defined(MBEDTLS_ECDSA_C) ) ) #define BUILTIN_ALG_ECDSA 1 #endif #if ( defined(MBEDTLS_PSA_BUILTIN_ALG_DETERMINISTIC_ECDSA) || \ ( defined(PSA_CRYPTO_DRIVER_TEST) && \ defined(MBEDTLS_PSA_ACCEL_ALG_DETERMINISTIC_ECDSA) && \ defined(MBEDTLS_ECDSA_C) && defined(MBEDTLS_ECDSA_DETERMINISTIC) ) ) #define BUILTIN_ALG_DETERMINISTIC_ECDSA 1 #endif #if defined(BUILTIN_KEY_TYPE_ECC_KEY_PAIR) || \ defined(BUILTIN_KEY_TYPE_ECC_PUBLIC_KEY) || \ defined(BUILTIN_ALG_ECDSA) || \ defined(BUILTIN_ALG_DETERMINISTIC_ECDSA) || \ defined(MBEDTLS_PSA_BUILTIN_ALG_ECDH) 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); /* Load the group. */ grp_id = mbedtls_ecc_group_of_psa(PSA_KEY_TYPE_ECC_GET_FAMILY(type), curve_bits, !explicit_bits); if (grp_id == MBEDTLS_ECP_DP_NONE) { /* We can't distinguish between a nonsensical family/size combination * (which would warrant PSA_ERROR_INVALID_ARGUMENT) and a * well-regarded curve that Mbed TLS just doesn't know about (which * would warrant PSA_ERROR_NOT_SUPPORTED). For uniformity with how * curves that Mbed TLS knows about but for which support is disabled * at build time, return NOT_SUPPORTED. */ 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(BUILTIN_KEY_TYPE_ECC_KEY_PAIR) || * defined(BUILTIN_KEY_TYPE_ECC_PUBLIC_KEY) || * defined(BUILTIN_ALG_ECDSA) || * defined(BUILTIN_ALG_DETERMINISTIC_ECDSA) || * defined(MBEDTLS_PSA_BUILTIN_ALG_ECDH) */ #if defined(BUILTIN_KEY_TYPE_ECC_KEY_PAIR) || \ defined(BUILTIN_KEY_TYPE_ECC_PUBLIC_KEY) static psa_status_t 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->core.type, attributes->core.bits, data, data_length, &ecp); if (status != PSA_SUCCESS) goto exit; if (PSA_KEY_TYPE_ECC_GET_FAMILY(attributes->core.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->core.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 { if (data_size < PSA_BITS_TO_BYTES(ecp->grp.nbits)) return (PSA_ERROR_BUFFER_TOO_SMALL); status = mbedtls_to_psa_error( mbedtls_ecp_write_key(ecp, data, PSA_BITS_TO_BYTES(ecp->grp.nbits))); if (status == PSA_SUCCESS) *data_length = PSA_BITS_TO_BYTES(ecp->grp.nbits); else memset(data, 0, data_size); return (status); } } static psa_status_t 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->core.type, attributes->core.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->core.type)), ecp, data, data_size, data_length); mbedtls_ecp_keypair_free(ecp); mbedtls_free(ecp); return (status); } #endif /* defined(BUILTIN_KEY_TYPE_ECC_KEY_PAIR) || * defined(BUILTIN_KEY_TYPE_ECC_PUBLIC_KEY) */ #if defined(BUILTIN_KEY_TYPE_ECC_KEY_PAIR) static psa_status_t 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->core.type); mbedtls_ecp_group_id grp_id = mbedtls_ecc_group_of_psa(curve, attributes->core.bits, 0); const mbedtls_ecp_curve_info *curve_info = mbedtls_ecp_curve_info_from_grp_id(grp_id); mbedtls_ecp_keypair ecp; if (attributes->domain_parameters_size != 0) return (PSA_ERROR_NOT_SUPPORTED); 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(&ecp, key_buffer, key_buffer_size)); mbedtls_ecp_keypair_free(&ecp); if (status == PSA_SUCCESS) *key_buffer_length = key_buffer_size; return (status); } #endif /* defined(BUILTIN_KEY_TYPE_ECC_KEY_PAIR) */ /****************************************************************/ /* ECDSA sign/verify */ /****************************************************************/ #if defined(BUILTIN_ALG_ECDSA) || \ defined(BUILTIN_ALG_DETERMINISTIC_ECDSA) static psa_status_t 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->core.type, attributes->core.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(BUILTIN_ALG_DETERMINISTIC_ECDSA) psa_algorithm_t hash_alg = PSA_ALG_SIGN_GET_HASH(alg); const mbedtls_md_info_t *md_info = mbedtls_md_info_from_psa(hash_alg); mbedtls_md_type_t md_alg = mbedtls_md_get_type(md_info); 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(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)); } static psa_status_t 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; int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; size_t curve_bytes; mbedtls_mpi r, s; (void)alg; status = mbedtls_psa_ecp_load_representation(attributes->core.type, attributes->core.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) { ret = MBEDTLS_ERR_ECP_VERIFY_FAILED; goto cleanup; } MBEDTLS_MPI_CHK(mbedtls_mpi_read_binary(&r, signature, curve_bytes)); MBEDTLS_MPI_CHK(mbedtls_mpi_read_binary(&s, signature + curve_bytes, curve_bytes)); /* Check whether the public part is loaded. If not, load it. */ if (mbedtls_ecp_is_zero(&ecp->Q)) { MBEDTLS_MPI_CHK( mbedtls_ecp_mul(&ecp->grp, &ecp->Q, &ecp->d, &ecp->grp.G, mbedtls_psa_get_random, MBEDTLS_PSA_RANDOM_STATE)); } ret = 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 (mbedtls_to_psa_error(ret)); } #endif /* defined(BUILTIN_ALG_ECDSA) || \ * defined(BUILTIN_ALG_DETERMINISTIC_ECDSA) */ #if defined(MBEDTLS_PSA_BUILTIN_KEY_TYPE_ECC_KEY_PAIR) || \ 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) { return (ecp_import_key(attributes, data, data_length, key_buffer, key_buffer_size, key_buffer_length, bits)); } 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) { return (ecp_export_public_key(attributes, key_buffer, key_buffer_size, data, data_size, data_length)); } #endif /* defined(MBEDTLS_PSA_BUILTIN_KEY_TYPE_ECC_KEY_PAIR) || * defined(MBEDTLS_PSA_BUILTIN_KEY_TYPE_ECC_PUBLIC_KEY) */ #if defined(MBEDTLS_PSA_BUILTIN_KEY_TYPE_ECC_KEY_PAIR) 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) { return (ecp_generate_key(attributes, key_buffer, key_buffer_size, key_buffer_length)); } #endif /* defined(MBEDTLS_PSA_BUILTIN_KEY_TYPE_ECC_KEY_PAIR) */ #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) { return (ecdsa_sign_hash(attributes, key_buffer, key_buffer_size, alg, hash, hash_length, signature, signature_size, signature_length)); } 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) { return (ecdsa_verify_hash(attributes, key_buffer, key_buffer_size, alg, hash, hash_length, signature, signature_length)); } #endif /* defined(MBEDTLS_PSA_BUILTIN_ALG_ECDSA) || * defined(MBEDTLS_PSA_BUILTIN_ALG_DETERMINISTIC_ECDSA) */ /* * BEYOND THIS POINT, TEST DRIVER ENTRY POINTS ONLY. */ #if defined(PSA_CRYPTO_DRIVER_TEST) #if defined(MBEDTLS_PSA_ACCEL_KEY_TYPE_ECC_KEY_PAIR) || \ defined(MBEDTLS_PSA_ACCEL_KEY_TYPE_ECC_PUBLIC_KEY) psa_status_t mbedtls_transparent_test_driver_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) { return (ecp_import_key(attributes, data, data_length, key_buffer, key_buffer_size, key_buffer_length, bits)); } psa_status_t mbedtls_transparent_test_driver_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) { return (ecp_export_public_key(attributes, key_buffer, key_buffer_size, data, data_size, data_length)); } #endif /* defined(MBEDTLS_PSA_ACCEL_KEY_TYPE_ECC_KEY_PAIR) || defined(MBEDTLS_PSA_ACCEL_KEY_TYPE_ECC_PUBLIC_KEY) */ #if defined(MBEDTLS_PSA_ACCEL_KEY_TYPE_ECC_KEY_PAIR) && \ defined(MBEDTLS_GENPRIME) psa_status_t mbedtls_transparent_test_driver_ecp_generate_key( const psa_key_attributes_t *attributes, uint8_t *key_buffer, size_t key_buffer_size, size_t *key_buffer_length) { return (ecp_generate_key(attributes, key_buffer, key_buffer_size, key_buffer_length)); } #endif /* defined(MBEDTLS_PSA_ACCEL_KEY_TYPE_ECC_KEY_PAIR) && defined(MBEDTLS_GENPRIME) */ #if defined(MBEDTLS_PSA_ACCEL_ALG_ECDSA) || \ defined(MBEDTLS_PSA_ACCEL_ALG_DETERMINISTIC_ECDSA) psa_status_t mbedtls_transparent_test_driver_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) { #if defined(MBEDTLS_ECDSA_C) return (ecdsa_sign_hash(attributes, key_buffer, key_buffer_size, alg, hash, hash_length, signature, signature_size, signature_length)); #else (void)attributes; (void)key_buffer; (void)key_buffer_size; (void)alg; (void)hash; (void)hash_length; (void)signature; (void)signature_size; (void)signature_length; return (PSA_ERROR_NOT_SUPPORTED); #endif } psa_status_t mbedtls_transparent_test_driver_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) { #if defined(MBEDTLS_ECDSA_C) return (ecdsa_verify_hash(attributes, key_buffer, key_buffer_size, alg, hash, hash_length, signature, signature_length)); #else (void)attributes; (void)key_buffer; (void)key_buffer_size; (void)alg; (void)hash; (void)hash_length; (void)signature; (void)signature_length; return (PSA_ERROR_NOT_SUPPORTED); #endif } #endif /* defined(MBEDTLS_PSA_ACCEL_ALG_ECDSA) || * defined(MBEDTLS_PSA_ACCEL_ALG_DETERMINISTIC_ECDSA) */ #endif /* PSA_CRYPTO_DRIVER_TEST */ #endif /* MBEDTLS_PSA_CRYPTO_C */