| /* |
| * 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 <psa/crypto.h> |
| #include "psa_crypto_core.h" |
| #include "psa_crypto_ecp.h" |
| #include "psa_crypto_random_impl.h" |
| #include "hash_info.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) || \ |
| 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) |
| 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(MBEDTLS_PSA_BUILTIN_KEY_TYPE_ECC_KEY_PAIR) || |
| * 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) || \ |
| 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->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 ); |
| } |
| } |
| |
| 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->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(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 ) |
| { |
| 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(MBEDTLS_PSA_BUILTIN_KEY_TYPE_ECC_KEY_PAIR) */ |
| |
| /****************************************************************/ |
| /* 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->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(MBEDTLS_PSA_BUILTIN_ALG_DETERMINISTIC_ECDSA) |
| psa_algorithm_t hash_alg = PSA_ALG_SIGN_GET_HASH( alg ); |
| mbedtls_md_type_t md_alg = mbedtls_hash_info_md_from_psa( 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_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(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->core.type ) || |
| ! PSA_ALG_IS_ECDH(alg) ) |
| return( PSA_ERROR_INVALID_ARGUMENT ); |
| 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 ); |
| 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 */ |
