| /* |
| * PSA RSA 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_random_impl.h" |
| #include "psa_crypto_rsa.h" |
| #include "psa_crypto_hash.h" |
| |
| #include <stdlib.h> |
| #include <string.h> |
| #include "mbedtls/platform.h" |
| |
| #include <mbedtls/rsa.h> |
| #include <mbedtls/error.h> |
| #include <mbedtls/pk.h> |
| #include <mbedtls/pk_internal.h> |
| |
| #if defined(MBEDTLS_PSA_BUILTIN_ALG_RSA_PKCS1V15_CRYPT) || \ |
| defined(MBEDTLS_PSA_BUILTIN_ALG_RSA_OAEP) || \ |
| defined(MBEDTLS_PSA_BUILTIN_ALG_RSA_PKCS1V15_SIGN) || \ |
| defined(MBEDTLS_PSA_BUILTIN_ALG_RSA_PSS) || \ |
| defined(MBEDTLS_PSA_BUILTIN_KEY_TYPE_RSA_KEY_PAIR) || \ |
| defined(MBEDTLS_PSA_BUILTIN_KEY_TYPE_RSA_PUBLIC_KEY) |
| |
| /* Mbed TLS doesn't support non-byte-aligned key sizes (i.e. key sizes |
| * that are not a multiple of 8) well. For example, there is only |
| * mbedtls_rsa_get_len(), which returns a number of bytes, and no |
| * way to return the exact bit size of a key. |
| * To keep things simple, reject non-byte-aligned key sizes. */ |
| static psa_status_t psa_check_rsa_key_byte_aligned( |
| const mbedtls_rsa_context *rsa) |
| { |
| mbedtls_mpi n; |
| psa_status_t status; |
| mbedtls_mpi_init(&n); |
| status = mbedtls_to_psa_error( |
| mbedtls_rsa_export(rsa, &n, NULL, NULL, NULL, NULL)); |
| if (status == PSA_SUCCESS) { |
| if (mbedtls_mpi_bitlen(&n) % 8 != 0) { |
| status = PSA_ERROR_NOT_SUPPORTED; |
| } |
| } |
| mbedtls_mpi_free(&n); |
| return status; |
| } |
| |
| psa_status_t mbedtls_psa_rsa_load_representation( |
| psa_key_type_t type, const uint8_t *data, size_t data_length, |
| mbedtls_rsa_context **p_rsa) |
| { |
| psa_status_t status; |
| mbedtls_pk_context ctx; |
| size_t bits; |
| mbedtls_pk_init(&ctx); |
| |
| /* Parse the data. */ |
| if (PSA_KEY_TYPE_IS_KEY_PAIR(type)) { |
| status = mbedtls_to_psa_error( |
| mbedtls_pk_parse_key(&ctx, data, data_length, NULL, 0)); |
| } else { |
| status = mbedtls_to_psa_error( |
| mbedtls_pk_parse_public_key(&ctx, data, data_length)); |
| } |
| if (status != PSA_SUCCESS) { |
| goto exit; |
| } |
| |
| /* We have something that the pkparse module recognizes. If it is a |
| * valid RSA key, store it. */ |
| if (mbedtls_pk_get_type(&ctx) != MBEDTLS_PK_RSA) { |
| status = PSA_ERROR_INVALID_ARGUMENT; |
| goto exit; |
| } |
| |
| /* The size of an RSA key doesn't have to be a multiple of 8. Mbed TLS |
| * supports non-byte-aligned key sizes, but not well. For example, |
| * mbedtls_rsa_get_len() returns the key size in bytes, not in bits. */ |
| bits = PSA_BYTES_TO_BITS(mbedtls_rsa_get_len(mbedtls_pk_rsa(ctx))); |
| if (bits > PSA_VENDOR_RSA_MAX_KEY_BITS) { |
| status = PSA_ERROR_NOT_SUPPORTED; |
| goto exit; |
| } |
| status = psa_check_rsa_key_byte_aligned(mbedtls_pk_rsa(ctx)); |
| if (status != PSA_SUCCESS) { |
| goto exit; |
| } |
| |
| /* Copy out the pointer to the RSA context, and reset the PK context |
| * such that pk_free doesn't free the RSA context we just grabbed. */ |
| *p_rsa = mbedtls_pk_rsa(ctx); |
| ctx.pk_info = NULL; |
| |
| exit: |
| mbedtls_pk_free(&ctx); |
| return status; |
| } |
| #endif /* defined(MBEDTLS_PSA_BUILTIN_ALG_RSA_PKCS1V15_CRYPT) || |
| * defined(MBEDTLS_PSA_BUILTIN_ALG_RSA_OAEP) || |
| * defined(MBEDTLS_PSA_BUILTIN_ALG_RSA_PKCS1V15_SIGN) || |
| * defined(MBEDTLS_PSA_BUILTIN_ALG_RSA_PSS) || |
| * defined(MBEDTLS_PSA_BUILTIN_KEY_TYPE_RSA_KEY_PAIR) || |
| * defined(MBEDTLS_PSA_BUILTIN_KEY_TYPE_RSA_PUBLIC_KEY) */ |
| |
| #if defined(MBEDTLS_PSA_BUILTIN_KEY_TYPE_RSA_KEY_PAIR) || \ |
| defined(MBEDTLS_PSA_BUILTIN_KEY_TYPE_RSA_PUBLIC_KEY) |
| |
| psa_status_t mbedtls_psa_rsa_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_rsa_context *rsa = NULL; |
| |
| /* Parse input */ |
| status = mbedtls_psa_rsa_load_representation(attributes->core.type, |
| data, |
| data_length, |
| &rsa); |
| if (status != PSA_SUCCESS) { |
| goto exit; |
| } |
| |
| *bits = (psa_key_bits_t) PSA_BYTES_TO_BITS(mbedtls_rsa_get_len(rsa)); |
| |
| /* Re-export the data to PSA export format, such that we can store export |
| * representation in the key slot. Export representation in case of RSA is |
| * the smallest representation that's allowed as input, so a straight-up |
| * allocation of the same size as the input buffer will be large enough. */ |
| status = mbedtls_psa_rsa_export_key(attributes->core.type, |
| rsa, |
| key_buffer, |
| key_buffer_size, |
| key_buffer_length); |
| exit: |
| /* Always free the RSA object */ |
| mbedtls_rsa_free(rsa); |
| mbedtls_free(rsa); |
| |
| return status; |
| } |
| |
| psa_status_t mbedtls_psa_rsa_export_key(psa_key_type_t type, |
| mbedtls_rsa_context *rsa, |
| uint8_t *data, |
| size_t data_size, |
| size_t *data_length) |
| { |
| #if defined(MBEDTLS_PK_WRITE_C) |
| int ret; |
| mbedtls_pk_context pk; |
| uint8_t *pos = data + data_size; |
| |
| mbedtls_pk_init(&pk); |
| pk.pk_info = &mbedtls_rsa_info; |
| pk.pk_ctx = rsa; |
| |
| /* PSA Crypto API defines the format of an RSA key as a DER-encoded |
| * representation of the non-encrypted PKCS#1 RSAPrivateKey for a |
| * private key and of the RFC3279 RSAPublicKey for a public key. */ |
| if (PSA_KEY_TYPE_IS_KEY_PAIR(type)) { |
| ret = mbedtls_pk_write_key_der(&pk, data, data_size); |
| } else { |
| ret = mbedtls_pk_write_pubkey(&pos, data, &pk); |
| } |
| |
| if (ret < 0) { |
| /* Clean up in case pk_write failed halfway through. */ |
| memset(data, 0, data_size); |
| return mbedtls_to_psa_error(ret); |
| } |
| |
| /* The mbedtls_pk_xxx functions write to the end of the buffer. |
| * Move the data to the beginning and erase remaining data |
| * at the original location. */ |
| if (2 * (size_t) ret <= data_size) { |
| memcpy(data, data + data_size - ret, ret); |
| memset(data + data_size - ret, 0, ret); |
| } else if ((size_t) ret < data_size) { |
| memmove(data, data + data_size - ret, ret); |
| memset(data + ret, 0, data_size - ret); |
| } |
| |
| *data_length = ret; |
| return PSA_SUCCESS; |
| #else |
| (void) type; |
| (void) rsa; |
| (void) data; |
| (void) data_size; |
| (void) data_length; |
| return PSA_ERROR_NOT_SUPPORTED; |
| #endif /* MBEDTLS_PK_WRITE_C */ |
| } |
| |
| psa_status_t mbedtls_psa_rsa_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_rsa_context *rsa = NULL; |
| |
| status = mbedtls_psa_rsa_load_representation( |
| attributes->core.type, key_buffer, key_buffer_size, &rsa); |
| if (status != PSA_SUCCESS) { |
| return status; |
| } |
| |
| status = mbedtls_psa_rsa_export_key(PSA_KEY_TYPE_RSA_PUBLIC_KEY, |
| rsa, |
| data, |
| data_size, |
| data_length); |
| |
| mbedtls_rsa_free(rsa); |
| mbedtls_free(rsa); |
| |
| return status; |
| } |
| #endif /* defined(MBEDTLS_PSA_BUILTIN_KEY_TYPE_RSA_KEY_PAIR) || |
| * defined(MBEDTLS_PSA_BUILTIN_KEY_TYPE_RSA_PUBLIC_KEY) */ |
| |
| #if defined(MBEDTLS_PSA_BUILTIN_KEY_TYPE_RSA_KEY_PAIR) && \ |
| defined(MBEDTLS_GENPRIME) |
| static psa_status_t psa_rsa_read_exponent(const uint8_t *domain_parameters, |
| size_t domain_parameters_size, |
| int *exponent) |
| { |
| size_t i; |
| uint32_t acc = 0; |
| |
| if (domain_parameters_size == 0) { |
| *exponent = 65537; |
| return PSA_SUCCESS; |
| } |
| |
| /* Mbed TLS encodes the public exponent as an int. For simplicity, only |
| * support values that fit in a 32-bit integer, which is larger than |
| * int on just about every platform anyway. */ |
| if (domain_parameters_size > sizeof(acc)) { |
| return PSA_ERROR_NOT_SUPPORTED; |
| } |
| for (i = 0; i < domain_parameters_size; i++) { |
| acc = (acc << 8) | domain_parameters[i]; |
| } |
| if (acc > INT_MAX) { |
| return PSA_ERROR_NOT_SUPPORTED; |
| } |
| *exponent = acc; |
| return PSA_SUCCESS; |
| } |
| |
| psa_status_t mbedtls_psa_rsa_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; |
| mbedtls_rsa_context rsa; |
| int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; |
| int exponent; |
| |
| status = psa_rsa_read_exponent(attributes->domain_parameters, |
| attributes->domain_parameters_size, |
| &exponent); |
| if (status != PSA_SUCCESS) { |
| return status; |
| } |
| |
| mbedtls_rsa_init(&rsa, MBEDTLS_RSA_PKCS_V15, MBEDTLS_MD_NONE); |
| ret = mbedtls_rsa_gen_key(&rsa, |
| mbedtls_psa_get_random, |
| MBEDTLS_PSA_RANDOM_STATE, |
| (unsigned int) attributes->core.bits, |
| exponent); |
| if (ret != 0) { |
| return mbedtls_to_psa_error(ret); |
| } |
| |
| status = mbedtls_psa_rsa_export_key(attributes->core.type, |
| &rsa, key_buffer, key_buffer_size, |
| key_buffer_length); |
| mbedtls_rsa_free(&rsa); |
| |
| return status; |
| } |
| #endif /* defined(MBEDTLS_PSA_BUILTIN_KEY_TYPE_RSA_KEY_PAIR) |
| * defined(MBEDTLS_GENPRIME) */ |
| |
| /****************************************************************/ |
| /* Sign/verify hashes */ |
| /****************************************************************/ |
| |
| #if defined(MBEDTLS_PSA_BUILTIN_ALG_RSA_PKCS1V15_SIGN) || \ |
| defined(MBEDTLS_PSA_BUILTIN_ALG_RSA_PSS) |
| |
| /* Decode the hash algorithm from alg and store the mbedtls encoding in |
| * md_alg. Verify that the hash length is acceptable. */ |
| static psa_status_t psa_rsa_decode_md_type(psa_algorithm_t alg, |
| size_t hash_length, |
| mbedtls_md_type_t *md_alg) |
| { |
| 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); |
| *md_alg = mbedtls_md_get_type(md_info); |
| |
| /* The Mbed TLS RSA module uses an unsigned int for hash length |
| * parameters. Validate that it fits so that we don't risk an |
| * overflow later. */ |
| #if SIZE_MAX > UINT_MAX |
| if (hash_length > UINT_MAX) { |
| return PSA_ERROR_INVALID_ARGUMENT; |
| } |
| #endif |
| |
| /* For signatures using a hash, the hash length must be correct. */ |
| if (alg != PSA_ALG_RSA_PKCS1V15_SIGN_RAW) { |
| if (md_info == NULL) { |
| return PSA_ERROR_NOT_SUPPORTED; |
| } |
| if (mbedtls_md_get_size(md_info) != hash_length) { |
| return PSA_ERROR_INVALID_ARGUMENT; |
| } |
| } |
| |
| return PSA_SUCCESS; |
| } |
| |
| psa_status_t mbedtls_psa_rsa_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_rsa_context *rsa = NULL; |
| int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; |
| mbedtls_md_type_t md_alg; |
| |
| status = mbedtls_psa_rsa_load_representation(attributes->core.type, |
| key_buffer, |
| key_buffer_size, |
| &rsa); |
| if (status != PSA_SUCCESS) { |
| return status; |
| } |
| |
| status = psa_rsa_decode_md_type(alg, hash_length, &md_alg); |
| if (status != PSA_SUCCESS) { |
| goto exit; |
| } |
| |
| if (signature_size < mbedtls_rsa_get_len(rsa)) { |
| status = PSA_ERROR_BUFFER_TOO_SMALL; |
| goto exit; |
| } |
| |
| #if defined(MBEDTLS_PSA_BUILTIN_ALG_RSA_PKCS1V15_SIGN) |
| if (PSA_ALG_IS_RSA_PKCS1V15_SIGN(alg)) { |
| mbedtls_rsa_set_padding(rsa, MBEDTLS_RSA_PKCS_V15, |
| MBEDTLS_MD_NONE); |
| ret = mbedtls_rsa_pkcs1_sign(rsa, |
| mbedtls_psa_get_random, |
| MBEDTLS_PSA_RANDOM_STATE, |
| MBEDTLS_RSA_PRIVATE, |
| md_alg, |
| (unsigned int) hash_length, |
| hash, |
| signature); |
| } else |
| #endif /* MBEDTLS_PSA_BUILTIN_ALG_RSA_PKCS1V15_SIGN */ |
| #if defined(MBEDTLS_PSA_BUILTIN_ALG_RSA_PSS) |
| if (PSA_ALG_IS_RSA_PSS(alg)) { |
| mbedtls_rsa_set_padding(rsa, MBEDTLS_RSA_PKCS_V21, md_alg); |
| ret = mbedtls_rsa_rsassa_pss_sign(rsa, |
| mbedtls_psa_get_random, |
| MBEDTLS_PSA_RANDOM_STATE, |
| MBEDTLS_RSA_PRIVATE, |
| MBEDTLS_MD_NONE, |
| (unsigned int) hash_length, |
| hash, |
| signature); |
| } else |
| #endif /* MBEDTLS_PSA_BUILTIN_ALG_RSA_PSS */ |
| { |
| status = PSA_ERROR_INVALID_ARGUMENT; |
| goto exit; |
| } |
| |
| if (ret == 0) { |
| *signature_length = mbedtls_rsa_get_len(rsa); |
| } |
| status = mbedtls_to_psa_error(ret); |
| |
| exit: |
| mbedtls_rsa_free(rsa); |
| mbedtls_free(rsa); |
| |
| return status; |
| } |
| |
| #if defined(MBEDTLS_PSA_BUILTIN_ALG_RSA_PSS) |
| static int rsa_pss_expected_salt_len(psa_algorithm_t alg, |
| const mbedtls_rsa_context *rsa, |
| size_t hash_length) |
| { |
| if (PSA_ALG_IS_RSA_PSS_ANY_SALT(alg)) { |
| return MBEDTLS_RSA_SALT_LEN_ANY; |
| } |
| /* Otherwise: standard salt length, i.e. largest possible salt length |
| * up to the hash length. */ |
| int klen = (int) mbedtls_rsa_get_len(rsa); // known to fit |
| int hlen = (int) hash_length; // known to fit |
| int room = klen - 2 - hlen; |
| if (room < 0) { |
| return 0; // there is no valid signature in this case anyway |
| } else if (room > hlen) { |
| return hlen; |
| } else { |
| return room; |
| } |
| } |
| #endif /* MBEDTLS_PSA_BUILTIN_ALG_RSA_PSS */ |
| |
| psa_status_t mbedtls_psa_rsa_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_rsa_context *rsa = NULL; |
| int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; |
| mbedtls_md_type_t md_alg; |
| |
| status = mbedtls_psa_rsa_load_representation(attributes->core.type, |
| key_buffer, |
| key_buffer_size, |
| &rsa); |
| if (status != PSA_SUCCESS) { |
| goto exit; |
| } |
| |
| status = psa_rsa_decode_md_type(alg, hash_length, &md_alg); |
| if (status != PSA_SUCCESS) { |
| goto exit; |
| } |
| |
| if (signature_length != mbedtls_rsa_get_len(rsa)) { |
| status = PSA_ERROR_INVALID_SIGNATURE; |
| goto exit; |
| } |
| |
| #if defined(MBEDTLS_PSA_BUILTIN_ALG_RSA_PKCS1V15_SIGN) |
| if (PSA_ALG_IS_RSA_PKCS1V15_SIGN(alg)) { |
| mbedtls_rsa_set_padding(rsa, MBEDTLS_RSA_PKCS_V15, |
| MBEDTLS_MD_NONE); |
| ret = mbedtls_rsa_pkcs1_verify(rsa, |
| mbedtls_psa_get_random, |
| MBEDTLS_PSA_RANDOM_STATE, |
| MBEDTLS_RSA_PUBLIC, |
| md_alg, |
| (unsigned int) hash_length, |
| hash, |
| signature); |
| } else |
| #endif /* MBEDTLS_PSA_BUILTIN_ALG_RSA_PKCS1V15_SIGN */ |
| #if defined(MBEDTLS_PSA_BUILTIN_ALG_RSA_PSS) |
| if (PSA_ALG_IS_RSA_PSS(alg)) { |
| int slen = rsa_pss_expected_salt_len(alg, rsa, hash_length); |
| mbedtls_rsa_set_padding(rsa, MBEDTLS_RSA_PKCS_V21, md_alg); |
| ret = mbedtls_rsa_rsassa_pss_verify_ext(rsa, |
| mbedtls_psa_get_random, |
| MBEDTLS_PSA_RANDOM_STATE, |
| MBEDTLS_RSA_PUBLIC, |
| md_alg, |
| (unsigned int) hash_length, |
| hash, |
| md_alg, |
| slen, |
| signature); |
| } else |
| #endif /* MBEDTLS_PSA_BUILTIN_ALG_RSA_PSS */ |
| { |
| status = PSA_ERROR_INVALID_ARGUMENT; |
| goto exit; |
| } |
| |
| /* Mbed TLS distinguishes "invalid padding" from "valid padding but |
| * the rest of the signature is invalid". This has little use in |
| * practice and PSA doesn't report this distinction. */ |
| status = (ret == MBEDTLS_ERR_RSA_INVALID_PADDING) ? |
| PSA_ERROR_INVALID_SIGNATURE : |
| mbedtls_to_psa_error(ret); |
| |
| exit: |
| mbedtls_rsa_free(rsa); |
| mbedtls_free(rsa); |
| |
| return status; |
| } |
| |
| #endif /* defined(MBEDTLS_PSA_BUILTIN_ALG_RSA_PKCS1V15_SIGN) || |
| * defined(MBEDTLS_PSA_BUILTIN_ALG_RSA_PSS) */ |
| |
| #endif /* MBEDTLS_PSA_CRYPTO_C */ |