/* * PSA crypto 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) #if defined(MBEDTLS_PSA_CRYPTO_CONFIG) #include "check_crypto_config.h" #endif #include "psa/crypto.h" #include "psa/crypto_values.h" #include "psa_crypto_cipher.h" #include "psa_crypto_core.h" #include "psa_crypto_invasive.h" #include "psa_crypto_driver_wrappers.h" #include "psa_crypto_ecp.h" #include "psa_crypto_hash.h" #include "psa_crypto_mac.h" #include "psa_crypto_rsa.h" #include "psa_crypto_ecp.h" #if defined(MBEDTLS_PSA_CRYPTO_SE_C) #include "psa_crypto_se.h" #endif #include "psa_crypto_slot_management.h" /* Include internal declarations that are useful for implementing persistently * stored keys. */ #include "psa_crypto_storage.h" #include "psa_crypto_random_impl.h" #include #include #include #include "mbedtls/platform.h" #if !defined(MBEDTLS_PLATFORM_C) #define mbedtls_calloc calloc #define mbedtls_free free #endif #include "mbedtls/aes.h" #include "mbedtls/asn1.h" #include "mbedtls/asn1write.h" #include "mbedtls/bignum.h" #include "mbedtls/camellia.h" #include "mbedtls/chacha20.h" #include "mbedtls/chachapoly.h" #include "mbedtls/cipher.h" #include "mbedtls/ccm.h" #include "mbedtls/cmac.h" #include "mbedtls/des.h" #include "mbedtls/ecdh.h" #include "mbedtls/ecp.h" #include "mbedtls/entropy.h" #include "mbedtls/error.h" #include "mbedtls/gcm.h" #include "mbedtls/md5.h" #include "mbedtls/md.h" #include "md_wrap.h" #include "mbedtls/pk.h" #include "pk_wrap.h" #include "mbedtls/platform_util.h" #include "mbedtls/error.h" #include "mbedtls/ripemd160.h" #include "mbedtls/rsa.h" #include "mbedtls/sha1.h" #include "mbedtls/sha256.h" #include "mbedtls/sha512.h" #define ARRAY_LENGTH( array ) ( sizeof( array ) / sizeof( *( array ) ) ) #if defined(MBEDTLS_PSA_BUILTIN_ALG_HKDF) || \ defined(MBEDTLS_PSA_BUILTIN_ALG_HKDF_EXTRACT) || \ defined(MBEDTLS_PSA_BUILTIN_ALG_HKDF_EXPAND) #define BUILTIN_ALG_ANY_HKDF 1 #endif /****************************************************************/ /* Global data, support functions and library management */ /****************************************************************/ static int key_type_is_raw_bytes( psa_key_type_t type ) { return( PSA_KEY_TYPE_IS_UNSTRUCTURED( type ) ); } /* Values for psa_global_data_t::rng_state */ #define RNG_NOT_INITIALIZED 0 #define RNG_INITIALIZED 1 #define RNG_SEEDED 2 typedef struct { unsigned initialized : 1; unsigned rng_state : 2; mbedtls_psa_random_context_t rng; } psa_global_data_t; static psa_global_data_t global_data; #if !defined(MBEDTLS_PSA_CRYPTO_EXTERNAL_RNG) mbedtls_psa_drbg_context_t *const mbedtls_psa_random_state = &global_data.rng.drbg; #endif #define GUARD_MODULE_INITIALIZED \ if( global_data.initialized == 0 ) \ return( PSA_ERROR_BAD_STATE ); psa_status_t mbedtls_to_psa_error( int ret ) { /* Mbed TLS error codes can combine a high-level error code and a * low-level error code. The low-level error usually reflects the * root cause better, so dispatch on that preferably. */ int low_level_ret = - ( -ret & 0x007f ); switch( low_level_ret != 0 ? low_level_ret : ret ) { case 0: return( PSA_SUCCESS ); case MBEDTLS_ERR_AES_INVALID_KEY_LENGTH: case MBEDTLS_ERR_AES_INVALID_INPUT_LENGTH: return( PSA_ERROR_NOT_SUPPORTED ); case MBEDTLS_ERR_ASN1_OUT_OF_DATA: case MBEDTLS_ERR_ASN1_UNEXPECTED_TAG: case MBEDTLS_ERR_ASN1_INVALID_LENGTH: case MBEDTLS_ERR_ASN1_LENGTH_MISMATCH: case MBEDTLS_ERR_ASN1_INVALID_DATA: return( PSA_ERROR_INVALID_ARGUMENT ); case MBEDTLS_ERR_ASN1_ALLOC_FAILED: return( PSA_ERROR_INSUFFICIENT_MEMORY ); case MBEDTLS_ERR_ASN1_BUF_TOO_SMALL: return( PSA_ERROR_BUFFER_TOO_SMALL ); #if defined(MBEDTLS_ERR_CAMELLIA_BAD_INPUT_DATA) case MBEDTLS_ERR_CAMELLIA_BAD_INPUT_DATA: #endif case MBEDTLS_ERR_CAMELLIA_INVALID_INPUT_LENGTH: return( PSA_ERROR_NOT_SUPPORTED ); case MBEDTLS_ERR_CCM_BAD_INPUT: return( PSA_ERROR_INVALID_ARGUMENT ); case MBEDTLS_ERR_CCM_AUTH_FAILED: return( PSA_ERROR_INVALID_SIGNATURE ); case MBEDTLS_ERR_CHACHA20_BAD_INPUT_DATA: return( PSA_ERROR_INVALID_ARGUMENT ); case MBEDTLS_ERR_CHACHAPOLY_BAD_STATE: return( PSA_ERROR_BAD_STATE ); case MBEDTLS_ERR_CHACHAPOLY_AUTH_FAILED: return( PSA_ERROR_INVALID_SIGNATURE ); case MBEDTLS_ERR_CIPHER_FEATURE_UNAVAILABLE: return( PSA_ERROR_NOT_SUPPORTED ); case MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA: return( PSA_ERROR_INVALID_ARGUMENT ); case MBEDTLS_ERR_CIPHER_ALLOC_FAILED: return( PSA_ERROR_INSUFFICIENT_MEMORY ); case MBEDTLS_ERR_CIPHER_INVALID_PADDING: return( PSA_ERROR_INVALID_PADDING ); case MBEDTLS_ERR_CIPHER_FULL_BLOCK_EXPECTED: return( PSA_ERROR_INVALID_ARGUMENT ); case MBEDTLS_ERR_CIPHER_AUTH_FAILED: return( PSA_ERROR_INVALID_SIGNATURE ); case MBEDTLS_ERR_CIPHER_INVALID_CONTEXT: return( PSA_ERROR_CORRUPTION_DETECTED ); #if !( defined(MBEDTLS_PSA_CRYPTO_EXTERNAL_RNG) || \ defined(MBEDTLS_PSA_HMAC_DRBG_MD_TYPE) ) /* Only check CTR_DRBG error codes if underlying mbedtls_xxx * functions are passed a CTR_DRBG instance. */ case MBEDTLS_ERR_CTR_DRBG_ENTROPY_SOURCE_FAILED: return( PSA_ERROR_INSUFFICIENT_ENTROPY ); case MBEDTLS_ERR_CTR_DRBG_REQUEST_TOO_BIG: case MBEDTLS_ERR_CTR_DRBG_INPUT_TOO_BIG: return( PSA_ERROR_NOT_SUPPORTED ); case MBEDTLS_ERR_CTR_DRBG_FILE_IO_ERROR: return( PSA_ERROR_INSUFFICIENT_ENTROPY ); #endif case MBEDTLS_ERR_DES_INVALID_INPUT_LENGTH: return( PSA_ERROR_NOT_SUPPORTED ); case MBEDTLS_ERR_ENTROPY_NO_SOURCES_DEFINED: case MBEDTLS_ERR_ENTROPY_NO_STRONG_SOURCE: case MBEDTLS_ERR_ENTROPY_SOURCE_FAILED: return( PSA_ERROR_INSUFFICIENT_ENTROPY ); case MBEDTLS_ERR_GCM_AUTH_FAILED: return( PSA_ERROR_INVALID_SIGNATURE ); case MBEDTLS_ERR_GCM_BUFFER_TOO_SMALL: return( PSA_ERROR_BUFFER_TOO_SMALL ); case MBEDTLS_ERR_GCM_BAD_INPUT: return( PSA_ERROR_INVALID_ARGUMENT ); #if !defined(MBEDTLS_PSA_CRYPTO_EXTERNAL_RNG) && \ defined(MBEDTLS_PSA_HMAC_DRBG_MD_TYPE) /* Only check HMAC_DRBG error codes if underlying mbedtls_xxx * functions are passed a HMAC_DRBG instance. */ case MBEDTLS_ERR_HMAC_DRBG_ENTROPY_SOURCE_FAILED: return( PSA_ERROR_INSUFFICIENT_ENTROPY ); case MBEDTLS_ERR_HMAC_DRBG_REQUEST_TOO_BIG: case MBEDTLS_ERR_HMAC_DRBG_INPUT_TOO_BIG: return( PSA_ERROR_NOT_SUPPORTED ); case MBEDTLS_ERR_HMAC_DRBG_FILE_IO_ERROR: return( PSA_ERROR_INSUFFICIENT_ENTROPY ); #endif case MBEDTLS_ERR_MD_FEATURE_UNAVAILABLE: return( PSA_ERROR_NOT_SUPPORTED ); case MBEDTLS_ERR_MD_BAD_INPUT_DATA: return( PSA_ERROR_INVALID_ARGUMENT ); case MBEDTLS_ERR_MD_ALLOC_FAILED: return( PSA_ERROR_INSUFFICIENT_MEMORY ); case MBEDTLS_ERR_MD_FILE_IO_ERROR: return( PSA_ERROR_STORAGE_FAILURE ); case MBEDTLS_ERR_MPI_FILE_IO_ERROR: return( PSA_ERROR_STORAGE_FAILURE ); case MBEDTLS_ERR_MPI_BAD_INPUT_DATA: return( PSA_ERROR_INVALID_ARGUMENT ); case MBEDTLS_ERR_MPI_INVALID_CHARACTER: return( PSA_ERROR_INVALID_ARGUMENT ); case MBEDTLS_ERR_MPI_BUFFER_TOO_SMALL: return( PSA_ERROR_BUFFER_TOO_SMALL ); case MBEDTLS_ERR_MPI_NEGATIVE_VALUE: return( PSA_ERROR_INVALID_ARGUMENT ); case MBEDTLS_ERR_MPI_DIVISION_BY_ZERO: return( PSA_ERROR_INVALID_ARGUMENT ); case MBEDTLS_ERR_MPI_NOT_ACCEPTABLE: return( PSA_ERROR_INVALID_ARGUMENT ); case MBEDTLS_ERR_MPI_ALLOC_FAILED: return( PSA_ERROR_INSUFFICIENT_MEMORY ); case MBEDTLS_ERR_PK_ALLOC_FAILED: return( PSA_ERROR_INSUFFICIENT_MEMORY ); case MBEDTLS_ERR_PK_TYPE_MISMATCH: case MBEDTLS_ERR_PK_BAD_INPUT_DATA: return( PSA_ERROR_INVALID_ARGUMENT ); case MBEDTLS_ERR_PK_FILE_IO_ERROR: return( PSA_ERROR_STORAGE_FAILURE ); case MBEDTLS_ERR_PK_KEY_INVALID_VERSION: case MBEDTLS_ERR_PK_KEY_INVALID_FORMAT: return( PSA_ERROR_INVALID_ARGUMENT ); case MBEDTLS_ERR_PK_UNKNOWN_PK_ALG: return( PSA_ERROR_NOT_SUPPORTED ); case MBEDTLS_ERR_PK_PASSWORD_REQUIRED: case MBEDTLS_ERR_PK_PASSWORD_MISMATCH: return( PSA_ERROR_NOT_PERMITTED ); case MBEDTLS_ERR_PK_INVALID_PUBKEY: return( PSA_ERROR_INVALID_ARGUMENT ); case MBEDTLS_ERR_PK_INVALID_ALG: case MBEDTLS_ERR_PK_UNKNOWN_NAMED_CURVE: case MBEDTLS_ERR_PK_FEATURE_UNAVAILABLE: return( PSA_ERROR_NOT_SUPPORTED ); case MBEDTLS_ERR_PK_SIG_LEN_MISMATCH: return( PSA_ERROR_INVALID_SIGNATURE ); case MBEDTLS_ERR_PK_BUFFER_TOO_SMALL: return( PSA_ERROR_BUFFER_TOO_SMALL ); case MBEDTLS_ERR_PLATFORM_HW_ACCEL_FAILED: return( PSA_ERROR_HARDWARE_FAILURE ); case MBEDTLS_ERR_PLATFORM_FEATURE_UNSUPPORTED: return( PSA_ERROR_NOT_SUPPORTED ); case MBEDTLS_ERR_RSA_BAD_INPUT_DATA: return( PSA_ERROR_INVALID_ARGUMENT ); case MBEDTLS_ERR_RSA_INVALID_PADDING: return( PSA_ERROR_INVALID_PADDING ); case MBEDTLS_ERR_RSA_KEY_GEN_FAILED: return( PSA_ERROR_HARDWARE_FAILURE ); case MBEDTLS_ERR_RSA_KEY_CHECK_FAILED: return( PSA_ERROR_INVALID_ARGUMENT ); case MBEDTLS_ERR_RSA_PUBLIC_FAILED: case MBEDTLS_ERR_RSA_PRIVATE_FAILED: return( PSA_ERROR_CORRUPTION_DETECTED ); case MBEDTLS_ERR_RSA_VERIFY_FAILED: return( PSA_ERROR_INVALID_SIGNATURE ); case MBEDTLS_ERR_RSA_OUTPUT_TOO_LARGE: return( PSA_ERROR_BUFFER_TOO_SMALL ); case MBEDTLS_ERR_RSA_RNG_FAILED: return( PSA_ERROR_INSUFFICIENT_ENTROPY ); case MBEDTLS_ERR_ECP_BAD_INPUT_DATA: case MBEDTLS_ERR_ECP_INVALID_KEY: return( PSA_ERROR_INVALID_ARGUMENT ); case MBEDTLS_ERR_ECP_BUFFER_TOO_SMALL: return( PSA_ERROR_BUFFER_TOO_SMALL ); case MBEDTLS_ERR_ECP_FEATURE_UNAVAILABLE: return( PSA_ERROR_NOT_SUPPORTED ); case MBEDTLS_ERR_ECP_SIG_LEN_MISMATCH: case MBEDTLS_ERR_ECP_VERIFY_FAILED: return( PSA_ERROR_INVALID_SIGNATURE ); case MBEDTLS_ERR_ECP_ALLOC_FAILED: return( PSA_ERROR_INSUFFICIENT_MEMORY ); case MBEDTLS_ERR_ECP_RANDOM_FAILED: return( PSA_ERROR_INSUFFICIENT_ENTROPY ); case MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED: return( PSA_ERROR_CORRUPTION_DETECTED ); default: return( PSA_ERROR_GENERIC_ERROR ); } } /****************************************************************/ /* Key management */ /****************************************************************/ #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) mbedtls_ecp_group_id mbedtls_ecc_group_of_psa( psa_ecc_family_t curve, size_t bits, int bits_is_sloppy ) { switch( curve ) { case PSA_ECC_FAMILY_SECP_R1: switch( bits ) { #if defined(PSA_WANT_ECC_SECP_R1_192) case 192: return( MBEDTLS_ECP_DP_SECP192R1 ); #endif #if defined(PSA_WANT_ECC_SECP_R1_224) case 224: return( MBEDTLS_ECP_DP_SECP224R1 ); #endif #if defined(PSA_WANT_ECC_SECP_R1_256) case 256: return( MBEDTLS_ECP_DP_SECP256R1 ); #endif #if defined(PSA_WANT_ECC_SECP_R1_384) case 384: return( MBEDTLS_ECP_DP_SECP384R1 ); #endif #if defined(PSA_WANT_ECC_SECP_R1_521) case 521: return( MBEDTLS_ECP_DP_SECP521R1 ); case 528: if( bits_is_sloppy ) return( MBEDTLS_ECP_DP_SECP521R1 ); break; #endif } break; case PSA_ECC_FAMILY_BRAINPOOL_P_R1: switch( bits ) { #if defined(PSA_WANT_ECC_BRAINPOOL_P_R1_256) case 256: return( MBEDTLS_ECP_DP_BP256R1 ); #endif #if defined(PSA_WANT_ECC_BRAINPOOL_P_R1_384) case 384: return( MBEDTLS_ECP_DP_BP384R1 ); #endif #if defined(PSA_WANT_ECC_BRAINPOOL_P_R1_512) case 512: return( MBEDTLS_ECP_DP_BP512R1 ); #endif } break; case PSA_ECC_FAMILY_MONTGOMERY: switch( bits ) { #if defined(PSA_WANT_ECC_MONTGOMERY_255) case 255: return( MBEDTLS_ECP_DP_CURVE25519 ); case 256: if( bits_is_sloppy ) return( MBEDTLS_ECP_DP_CURVE25519 ); break; #endif #if defined(PSA_WANT_ECC_MONTGOMERY_448) case 448: return( MBEDTLS_ECP_DP_CURVE448 ); #endif } break; case PSA_ECC_FAMILY_SECP_K1: switch( bits ) { #if defined(PSA_WANT_ECC_SECP_K1_192) case 192: return( MBEDTLS_ECP_DP_SECP192K1 ); #endif #if defined(PSA_WANT_ECC_SECP_K1_224) case 224: return( MBEDTLS_ECP_DP_SECP224K1 ); #endif #if defined(PSA_WANT_ECC_SECP_K1_256) case 256: return( MBEDTLS_ECP_DP_SECP256K1 ); #endif } break; } (void) bits_is_sloppy; return( MBEDTLS_ECP_DP_NONE ); } #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) */ psa_status_t psa_validate_unstructured_key_bit_size( psa_key_type_t type, size_t bits ) { /* Check that the bit size is acceptable for the key type */ switch( type ) { case PSA_KEY_TYPE_RAW_DATA: case PSA_KEY_TYPE_HMAC: case PSA_KEY_TYPE_DERIVE: case PSA_KEY_TYPE_PASSWORD: case PSA_KEY_TYPE_PASSWORD_HASH: break; #if defined(PSA_WANT_KEY_TYPE_AES) case PSA_KEY_TYPE_AES: if( bits != 128 && bits != 192 && bits != 256 ) return( PSA_ERROR_INVALID_ARGUMENT ); break; #endif #if defined(PSA_WANT_KEY_TYPE_ARIA) case PSA_KEY_TYPE_ARIA: if( bits != 128 && bits != 192 && bits != 256 ) return( PSA_ERROR_INVALID_ARGUMENT ); break; #endif #if defined(PSA_WANT_KEY_TYPE_CAMELLIA) case PSA_KEY_TYPE_CAMELLIA: if( bits != 128 && bits != 192 && bits != 256 ) return( PSA_ERROR_INVALID_ARGUMENT ); break; #endif #if defined(PSA_WANT_KEY_TYPE_DES) case PSA_KEY_TYPE_DES: if( bits != 64 && bits != 128 && bits != 192 ) return( PSA_ERROR_INVALID_ARGUMENT ); break; #endif #if defined(PSA_WANT_KEY_TYPE_CHACHA20) case PSA_KEY_TYPE_CHACHA20: if( bits != 256 ) return( PSA_ERROR_INVALID_ARGUMENT ); break; #endif default: return( PSA_ERROR_NOT_SUPPORTED ); } if( bits % 8 != 0 ) return( PSA_ERROR_INVALID_ARGUMENT ); return( PSA_SUCCESS ); } /** Check whether a given key type is valid for use with a given MAC algorithm * * Upon successful return of this function, the behavior of #PSA_MAC_LENGTH * when called with the validated \p algorithm and \p key_type is well-defined. * * \param[in] algorithm The specific MAC algorithm (can be wildcard). * \param[in] key_type The key type of the key to be used with the * \p algorithm. * * \retval #PSA_SUCCESS * The \p key_type is valid for use with the \p algorithm * \retval #PSA_ERROR_INVALID_ARGUMENT * The \p key_type is not valid for use with the \p algorithm */ MBEDTLS_STATIC_TESTABLE psa_status_t psa_mac_key_can_do( psa_algorithm_t algorithm, psa_key_type_t key_type ) { if( PSA_ALG_IS_HMAC( algorithm ) ) { if( key_type == PSA_KEY_TYPE_HMAC ) return( PSA_SUCCESS ); } if( PSA_ALG_IS_BLOCK_CIPHER_MAC( algorithm ) ) { /* Check that we're calling PSA_BLOCK_CIPHER_BLOCK_LENGTH with a cipher * key. */ if( ( key_type & PSA_KEY_TYPE_CATEGORY_MASK ) == PSA_KEY_TYPE_CATEGORY_SYMMETRIC ) { /* PSA_BLOCK_CIPHER_BLOCK_LENGTH returns 1 for stream ciphers and * the block length (larger than 1) for block ciphers. */ if( PSA_BLOCK_CIPHER_BLOCK_LENGTH( key_type ) > 1 ) return( PSA_SUCCESS ); } } return( PSA_ERROR_INVALID_ARGUMENT ); } psa_status_t psa_allocate_buffer_to_slot( psa_key_slot_t *slot, size_t buffer_length ) { if( slot->key.data != NULL ) return( PSA_ERROR_ALREADY_EXISTS ); slot->key.data = mbedtls_calloc( 1, buffer_length ); if( slot->key.data == NULL ) return( PSA_ERROR_INSUFFICIENT_MEMORY ); slot->key.bytes = buffer_length; return( PSA_SUCCESS ); } psa_status_t psa_copy_key_material_into_slot( psa_key_slot_t *slot, const uint8_t* data, size_t data_length ) { psa_status_t status = psa_allocate_buffer_to_slot( slot, data_length ); if( status != PSA_SUCCESS ) return( status ); memcpy( slot->key.data, data, data_length ); return( PSA_SUCCESS ); } psa_status_t psa_import_key_into_slot( 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 = PSA_ERROR_CORRUPTION_DETECTED; psa_key_type_t type = attributes->core.type; /* zero-length keys are never supported. */ if( data_length == 0 ) return( PSA_ERROR_NOT_SUPPORTED ); if( key_type_is_raw_bytes( type ) ) { *bits = PSA_BYTES_TO_BITS( data_length ); status = psa_validate_unstructured_key_bit_size( attributes->core.type, *bits ); if( status != PSA_SUCCESS ) return( status ); /* Copy the key material. */ memcpy( key_buffer, data, data_length ); *key_buffer_length = data_length; (void)key_buffer_size; return( PSA_SUCCESS ); } else if( PSA_KEY_TYPE_IS_ASYMMETRIC( type ) ) { #if defined(MBEDTLS_PSA_BUILTIN_KEY_TYPE_ECC_KEY_PAIR) || \ defined(MBEDTLS_PSA_BUILTIN_KEY_TYPE_ECC_PUBLIC_KEY) if( PSA_KEY_TYPE_IS_ECC( type ) ) { return( mbedtls_psa_ecp_import_key( attributes, data, data_length, key_buffer, key_buffer_size, key_buffer_length, bits ) ); } #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_RSA_KEY_PAIR) || \ defined(MBEDTLS_PSA_BUILTIN_KEY_TYPE_RSA_PUBLIC_KEY) if( PSA_KEY_TYPE_IS_RSA( type ) ) { return( mbedtls_psa_rsa_import_key( attributes, data, data_length, key_buffer, key_buffer_size, key_buffer_length, bits ) ); } #endif /* defined(MBEDTLS_PSA_BUILTIN_KEY_TYPE_RSA_KEY_PAIR) || * defined(MBEDTLS_PSA_BUILTIN_KEY_TYPE_RSA_PUBLIC_KEY) */ } return( PSA_ERROR_NOT_SUPPORTED ); } /** Calculate the intersection of two algorithm usage policies. * * Return 0 (which allows no operation) on incompatibility. */ static psa_algorithm_t psa_key_policy_algorithm_intersection( psa_key_type_t key_type, psa_algorithm_t alg1, psa_algorithm_t alg2 ) { /* Common case: both sides actually specify the same policy. */ if( alg1 == alg2 ) return( alg1 ); /* If the policies are from the same hash-and-sign family, check * if one is a wildcard. If so the other has the specific algorithm. */ if( PSA_ALG_IS_SIGN_HASH( alg1 ) && PSA_ALG_IS_SIGN_HASH( alg2 ) && ( alg1 & ~PSA_ALG_HASH_MASK ) == ( alg2 & ~PSA_ALG_HASH_MASK ) ) { if( PSA_ALG_SIGN_GET_HASH( alg1 ) == PSA_ALG_ANY_HASH ) return( alg2 ); if( PSA_ALG_SIGN_GET_HASH( alg2 ) == PSA_ALG_ANY_HASH ) return( alg1 ); } /* If the policies are from the same AEAD family, check whether * one of them is a minimum-tag-length wildcard. Calculate the most * restrictive tag length. */ if( PSA_ALG_IS_AEAD( alg1 ) && PSA_ALG_IS_AEAD( alg2 ) && ( PSA_ALG_AEAD_WITH_SHORTENED_TAG( alg1, 0 ) == PSA_ALG_AEAD_WITH_SHORTENED_TAG( alg2, 0 ) ) ) { size_t alg1_len = PSA_ALG_AEAD_GET_TAG_LENGTH( alg1 ); size_t alg2_len = PSA_ALG_AEAD_GET_TAG_LENGTH( alg2 ); size_t restricted_len = alg1_len > alg2_len ? alg1_len : alg2_len; /* If both are wildcards, return most restrictive wildcard */ if( ( ( alg1 & PSA_ALG_AEAD_AT_LEAST_THIS_LENGTH_FLAG ) != 0 ) && ( ( alg2 & PSA_ALG_AEAD_AT_LEAST_THIS_LENGTH_FLAG ) != 0 ) ) { return( PSA_ALG_AEAD_WITH_AT_LEAST_THIS_LENGTH_TAG( alg1, restricted_len ) ); } /* If only one is a wildcard, return specific algorithm if compatible. */ if( ( ( alg1 & PSA_ALG_AEAD_AT_LEAST_THIS_LENGTH_FLAG ) != 0 ) && ( alg1_len <= alg2_len ) ) { return( alg2 ); } if( ( ( alg2 & PSA_ALG_AEAD_AT_LEAST_THIS_LENGTH_FLAG ) != 0 ) && ( alg2_len <= alg1_len ) ) { return( alg1 ); } } /* If the policies are from the same MAC family, check whether one * of them is a minimum-MAC-length policy. Calculate the most * restrictive tag length. */ if( PSA_ALG_IS_MAC( alg1 ) && PSA_ALG_IS_MAC( alg2 ) && ( PSA_ALG_FULL_LENGTH_MAC( alg1 ) == PSA_ALG_FULL_LENGTH_MAC( alg2 ) ) ) { /* Validate the combination of key type and algorithm. Since the base * algorithm of alg1 and alg2 are the same, we only need this once. */ if( PSA_SUCCESS != psa_mac_key_can_do( alg1, key_type ) ) return( 0 ); /* Get the (exact or at-least) output lengths for both sides of the * requested intersection. None of the currently supported algorithms * have an output length dependent on the actual key size, so setting it * to a bogus value of 0 is currently OK. * * Note that for at-least-this-length wildcard algorithms, the output * length is set to the shortest allowed length, which allows us to * calculate the most restrictive tag length for the intersection. */ size_t alg1_len = PSA_MAC_LENGTH( key_type, 0, alg1 ); size_t alg2_len = PSA_MAC_LENGTH( key_type, 0, alg2 ); size_t restricted_len = alg1_len > alg2_len ? alg1_len : alg2_len; /* If both are wildcards, return most restrictive wildcard */ if( ( ( alg1 & PSA_ALG_MAC_AT_LEAST_THIS_LENGTH_FLAG ) != 0 ) && ( ( alg2 & PSA_ALG_MAC_AT_LEAST_THIS_LENGTH_FLAG ) != 0 ) ) { return( PSA_ALG_AT_LEAST_THIS_LENGTH_MAC( alg1, restricted_len ) ); } /* If only one is an at-least-this-length policy, the intersection would * be the other (fixed-length) policy as long as said fixed length is * equal to or larger than the shortest allowed length. */ if( ( alg1 & PSA_ALG_MAC_AT_LEAST_THIS_LENGTH_FLAG ) != 0 ) { return( ( alg1_len <= alg2_len ) ? alg2 : 0 ); } if( ( alg2 & PSA_ALG_MAC_AT_LEAST_THIS_LENGTH_FLAG ) != 0 ) { return( ( alg2_len <= alg1_len ) ? alg1 : 0 ); } /* If none of them are wildcards, check whether they define the same tag * length. This is still possible here when one is default-length and * the other specific-length. Ensure to always return the * specific-length version for the intersection. */ if( alg1_len == alg2_len ) return( PSA_ALG_TRUNCATED_MAC( alg1, alg1_len ) ); } /* If the policies are incompatible, allow nothing. */ return( 0 ); } static int psa_key_algorithm_permits( psa_key_type_t key_type, psa_algorithm_t policy_alg, psa_algorithm_t requested_alg ) { /* Common case: the policy only allows requested_alg. */ if( requested_alg == policy_alg ) return( 1 ); /* If policy_alg is a hash-and-sign with a wildcard for the hash, * and requested_alg is the same hash-and-sign family with any hash, * then requested_alg is compliant with policy_alg. */ if( PSA_ALG_IS_SIGN_HASH( requested_alg ) && PSA_ALG_SIGN_GET_HASH( policy_alg ) == PSA_ALG_ANY_HASH ) { return( ( policy_alg & ~PSA_ALG_HASH_MASK ) == ( requested_alg & ~PSA_ALG_HASH_MASK ) ); } /* If policy_alg is a wildcard AEAD algorithm of the same base as * the requested algorithm, check the requested tag length to be * equal-length or longer than the wildcard-specified length. */ if( PSA_ALG_IS_AEAD( policy_alg ) && PSA_ALG_IS_AEAD( requested_alg ) && ( PSA_ALG_AEAD_WITH_SHORTENED_TAG( policy_alg, 0 ) == PSA_ALG_AEAD_WITH_SHORTENED_TAG( requested_alg, 0 ) ) && ( ( policy_alg & PSA_ALG_AEAD_AT_LEAST_THIS_LENGTH_FLAG ) != 0 ) ) { return( PSA_ALG_AEAD_GET_TAG_LENGTH( policy_alg ) <= PSA_ALG_AEAD_GET_TAG_LENGTH( requested_alg ) ); } /* If policy_alg is a MAC algorithm of the same base as the requested * algorithm, check whether their MAC lengths are compatible. */ if( PSA_ALG_IS_MAC( policy_alg ) && PSA_ALG_IS_MAC( requested_alg ) && ( PSA_ALG_FULL_LENGTH_MAC( policy_alg ) == PSA_ALG_FULL_LENGTH_MAC( requested_alg ) ) ) { /* Validate the combination of key type and algorithm. Since the policy * and requested algorithms are the same, we only need this once. */ if( PSA_SUCCESS != psa_mac_key_can_do( policy_alg, key_type ) ) return( 0 ); /* Get both the requested output length for the algorithm which is to be * verified, and the default output length for the base algorithm. * Note that none of the currently supported algorithms have an output * length dependent on actual key size, so setting it to a bogus value * of 0 is currently OK. */ size_t requested_output_length = PSA_MAC_LENGTH( key_type, 0, requested_alg ); size_t default_output_length = PSA_MAC_LENGTH( key_type, 0, PSA_ALG_FULL_LENGTH_MAC( requested_alg ) ); /* If the policy is default-length, only allow an algorithm with * a declared exact-length matching the default. */ if( PSA_MAC_TRUNCATED_LENGTH( policy_alg ) == 0 ) return( requested_output_length == default_output_length ); /* If the requested algorithm is default-length, allow it if the policy * length exactly matches the default length. */ if( PSA_MAC_TRUNCATED_LENGTH( requested_alg ) == 0 && PSA_MAC_TRUNCATED_LENGTH( policy_alg ) == default_output_length ) { return( 1 ); } /* If policy_alg is an at-least-this-length wildcard MAC algorithm, * check for the requested MAC length to be equal to or longer than the * minimum allowed length. */ if( ( policy_alg & PSA_ALG_MAC_AT_LEAST_THIS_LENGTH_FLAG ) != 0 ) { return( PSA_MAC_TRUNCATED_LENGTH( policy_alg ) <= requested_output_length ); } } /* If policy_alg is a generic key agreement operation, then using it for * a key derivation with that key agreement should also be allowed. This * behaviour is expected to be defined in a future specification version. */ if( PSA_ALG_IS_RAW_KEY_AGREEMENT( policy_alg ) && PSA_ALG_IS_KEY_AGREEMENT( requested_alg ) ) { return( PSA_ALG_KEY_AGREEMENT_GET_BASE( requested_alg ) == policy_alg ); } /* If it isn't explicitly permitted, it's forbidden. */ return( 0 ); } /** Test whether a policy permits an algorithm. * * The caller must test usage flags separately. * * \note This function requires providing the key type for which the policy is * being validated, since some algorithm policy definitions (e.g. MAC) * have different properties depending on what kind of cipher it is * combined with. * * \retval PSA_SUCCESS When \p alg is a specific algorithm * allowed by the \p policy. * \retval PSA_ERROR_INVALID_ARGUMENT When \p alg is not a specific algorithm * \retval PSA_ERROR_NOT_PERMITTED When \p alg is a specific algorithm, but * the \p policy does not allow it. */ static psa_status_t psa_key_policy_permits( const psa_key_policy_t *policy, psa_key_type_t key_type, psa_algorithm_t alg ) { /* '0' is not a valid algorithm */ if( alg == 0 ) return( PSA_ERROR_INVALID_ARGUMENT ); /* A requested algorithm cannot be a wildcard. */ if( PSA_ALG_IS_WILDCARD( alg ) ) return( PSA_ERROR_INVALID_ARGUMENT ); if( psa_key_algorithm_permits( key_type, policy->alg, alg ) || psa_key_algorithm_permits( key_type, policy->alg2, alg ) ) return( PSA_SUCCESS ); else return( PSA_ERROR_NOT_PERMITTED ); } /** Restrict a key policy based on a constraint. * * \note This function requires providing the key type for which the policy is * being restricted, since some algorithm policy definitions (e.g. MAC) * have different properties depending on what kind of cipher it is * combined with. * * \param[in] key_type The key type for which to restrict the policy * \param[in,out] policy The policy to restrict. * \param[in] constraint The policy constraint to apply. * * \retval #PSA_SUCCESS * \c *policy contains the intersection of the original value of * \c *policy and \c *constraint. * \retval #PSA_ERROR_INVALID_ARGUMENT * \c key_type, \c *policy and \c *constraint are incompatible. * \c *policy is unchanged. */ static psa_status_t psa_restrict_key_policy( psa_key_type_t key_type, psa_key_policy_t *policy, const psa_key_policy_t *constraint ) { psa_algorithm_t intersection_alg = psa_key_policy_algorithm_intersection( key_type, policy->alg, constraint->alg ); psa_algorithm_t intersection_alg2 = psa_key_policy_algorithm_intersection( key_type, policy->alg2, constraint->alg2 ); if( intersection_alg == 0 && policy->alg != 0 && constraint->alg != 0 ) return( PSA_ERROR_INVALID_ARGUMENT ); if( intersection_alg2 == 0 && policy->alg2 != 0 && constraint->alg2 != 0 ) return( PSA_ERROR_INVALID_ARGUMENT ); policy->usage &= constraint->usage; policy->alg = intersection_alg; policy->alg2 = intersection_alg2; return( PSA_SUCCESS ); } /** Get the description of a key given its identifier and policy constraints * and lock it. * * The key must have allow all the usage flags set in \p usage. If \p alg is * nonzero, the key must allow operations with this algorithm. If \p alg is * zero, the algorithm is not checked. * * In case of a persistent key, the function loads the description of the key * into a key slot if not already done. * * On success, the returned key slot is locked. It is the responsibility of * the caller to unlock the key slot when it does not access it anymore. */ static psa_status_t psa_get_and_lock_key_slot_with_policy( mbedtls_svc_key_id_t key, psa_key_slot_t **p_slot, psa_key_usage_t usage, psa_algorithm_t alg ) { psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED; psa_key_slot_t *slot; status = psa_get_and_lock_key_slot( key, p_slot ); if( status != PSA_SUCCESS ) return( status ); slot = *p_slot; /* Enforce that usage policy for the key slot contains all the flags * required by the usage parameter. There is one exception: public * keys can always be exported, so we treat public key objects as * if they had the export flag. */ if( PSA_KEY_TYPE_IS_PUBLIC_KEY( slot->attr.type ) ) usage &= ~PSA_KEY_USAGE_EXPORT; if( ( slot->attr.policy.usage & usage ) != usage ) { status = PSA_ERROR_NOT_PERMITTED; goto error; } /* Enforce that the usage policy permits the requested algorithm. */ if( alg != 0 ) { status = psa_key_policy_permits( &slot->attr.policy, slot->attr.type, alg ); if( status != PSA_SUCCESS ) goto error; } return( PSA_SUCCESS ); error: *p_slot = NULL; psa_unlock_key_slot( slot ); return( status ); } /** Get a key slot containing a transparent key and lock it. * * A transparent key is a key for which the key material is directly * available, as opposed to a key in a secure element and/or to be used * by a secure element. * * This is a temporary function that may be used instead of * psa_get_and_lock_key_slot_with_policy() when there is no opaque key support * for a cryptographic operation. * * On success, the returned key slot is locked. It is the responsibility of the * caller to unlock the key slot when it does not access it anymore. */ static psa_status_t psa_get_and_lock_transparent_key_slot_with_policy( mbedtls_svc_key_id_t key, psa_key_slot_t **p_slot, psa_key_usage_t usage, psa_algorithm_t alg ) { psa_status_t status = psa_get_and_lock_key_slot_with_policy( key, p_slot, usage, alg ); if( status != PSA_SUCCESS ) return( status ); if( psa_key_lifetime_is_external( (*p_slot)->attr.lifetime ) ) { psa_unlock_key_slot( *p_slot ); *p_slot = NULL; return( PSA_ERROR_NOT_SUPPORTED ); } return( PSA_SUCCESS ); } psa_status_t psa_remove_key_data_from_memory( psa_key_slot_t *slot ) { /* Data pointer will always be either a valid pointer or NULL in an * initialized slot, so we can just free it. */ if( slot->key.data != NULL ) mbedtls_platform_zeroize( slot->key.data, slot->key.bytes); mbedtls_free( slot->key.data ); slot->key.data = NULL; slot->key.bytes = 0; return( PSA_SUCCESS ); } /** Completely wipe a slot in memory, including its policy. * Persistent storage is not affected. */ psa_status_t psa_wipe_key_slot( psa_key_slot_t *slot ) { psa_status_t status = psa_remove_key_data_from_memory( slot ); /* * As the return error code may not be handled in case of multiple errors, * do our best to report an unexpected lock counter. Assert with * MBEDTLS_TEST_HOOK_TEST_ASSERT that the lock counter is equal to one: * if the MBEDTLS_TEST_HOOKS configuration option is enabled and the * function is called as part of the execution of a test suite, the * execution of the test suite is stopped in error if the assertion fails. */ if( slot->lock_count != 1 ) { MBEDTLS_TEST_HOOK_TEST_ASSERT( slot->lock_count == 1 ); status = PSA_ERROR_CORRUPTION_DETECTED; } /* Multipart operations may still be using the key. This is safe * because all multipart operation objects are independent from * the key slot: if they need to access the key after the setup * phase, they have a copy of the key. Note that this means that * key material can linger until all operations are completed. */ /* At this point, key material and other type-specific content has * been wiped. Clear remaining metadata. We can call memset and not * zeroize because the metadata is not particularly sensitive. */ memset( slot, 0, sizeof( *slot ) ); return( status ); } psa_status_t psa_destroy_key( mbedtls_svc_key_id_t key ) { psa_key_slot_t *slot; psa_status_t status; /* status of the last operation */ psa_status_t overall_status = PSA_SUCCESS; #if defined(MBEDTLS_PSA_CRYPTO_SE_C) psa_se_drv_table_entry_t *driver; #endif /* MBEDTLS_PSA_CRYPTO_SE_C */ if( mbedtls_svc_key_id_is_null( key ) ) return( PSA_SUCCESS ); /* * Get the description of the key in a key slot. In case of a persistent * key, this will load the key description from persistent memory if not * done yet. We cannot avoid this loading as without it we don't know if * the key is operated by an SE or not and this information is needed by * the current implementation. */ status = psa_get_and_lock_key_slot( key, &slot ); if( status != PSA_SUCCESS ) return( status ); /* * If the key slot containing the key description is under access by the * library (apart from the present access), the key cannot be destroyed * yet. For the time being, just return in error. Eventually (to be * implemented), the key should be destroyed when all accesses have * stopped. */ if( slot->lock_count > 1 ) { psa_unlock_key_slot( slot ); return( PSA_ERROR_GENERIC_ERROR ); } if( PSA_KEY_LIFETIME_IS_READ_ONLY( slot->attr.lifetime ) ) { /* Refuse the destruction of a read-only key (which may or may not work * if we attempt it, depending on whether the key is merely read-only * by policy or actually physically read-only). * Just do the best we can, which is to wipe the copy in memory * (done in this function's cleanup code). */ overall_status = PSA_ERROR_NOT_PERMITTED; goto exit; } #if defined(MBEDTLS_PSA_CRYPTO_SE_C) driver = psa_get_se_driver_entry( slot->attr.lifetime ); if( driver != NULL ) { /* For a key in a secure element, we need to do three things: * remove the key file in internal storage, destroy the * key inside the secure element, and update the driver's * persistent data. Start a transaction that will encompass these * three actions. */ psa_crypto_prepare_transaction( PSA_CRYPTO_TRANSACTION_DESTROY_KEY ); psa_crypto_transaction.key.lifetime = slot->attr.lifetime; psa_crypto_transaction.key.slot = psa_key_slot_get_slot_number( slot ); psa_crypto_transaction.key.id = slot->attr.id; status = psa_crypto_save_transaction( ); if( status != PSA_SUCCESS ) { (void) psa_crypto_stop_transaction( ); /* We should still try to destroy the key in the secure * element and the key metadata in storage. This is especially * important if the error is that the storage is full. * But how to do it exactly without risking an inconsistent * state after a reset? * https://github.com/ARMmbed/mbed-crypto/issues/215 */ overall_status = status; goto exit; } status = psa_destroy_se_key( driver, psa_key_slot_get_slot_number( slot ) ); if( overall_status == PSA_SUCCESS ) overall_status = status; } #endif /* MBEDTLS_PSA_CRYPTO_SE_C */ #if defined(MBEDTLS_PSA_CRYPTO_STORAGE_C) if( ! PSA_KEY_LIFETIME_IS_VOLATILE( slot->attr.lifetime ) ) { status = psa_destroy_persistent_key( slot->attr.id ); if( overall_status == PSA_SUCCESS ) overall_status = status; /* TODO: other slots may have a copy of the same key. We should * invalidate them. * https://github.com/ARMmbed/mbed-crypto/issues/214 */ } #endif /* defined(MBEDTLS_PSA_CRYPTO_STORAGE_C) */ #if defined(MBEDTLS_PSA_CRYPTO_SE_C) if( driver != NULL ) { status = psa_save_se_persistent_data( driver ); if( overall_status == PSA_SUCCESS ) overall_status = status; status = psa_crypto_stop_transaction( ); if( overall_status == PSA_SUCCESS ) overall_status = status; } #endif /* MBEDTLS_PSA_CRYPTO_SE_C */ exit: status = psa_wipe_key_slot( slot ); /* Prioritize CORRUPTION_DETECTED from wiping over a storage error */ if( status != PSA_SUCCESS ) overall_status = status; return( overall_status ); } #if defined(MBEDTLS_PSA_BUILTIN_KEY_TYPE_RSA_KEY_PAIR) || \ defined(MBEDTLS_PSA_BUILTIN_KEY_TYPE_RSA_PUBLIC_KEY) static psa_status_t psa_get_rsa_public_exponent( const mbedtls_rsa_context *rsa, psa_key_attributes_t *attributes ) { mbedtls_mpi mpi; int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; uint8_t *buffer = NULL; size_t buflen; mbedtls_mpi_init( &mpi ); ret = mbedtls_rsa_export( rsa, NULL, NULL, NULL, NULL, &mpi ); if( ret != 0 ) goto exit; if( mbedtls_mpi_cmp_int( &mpi, 65537 ) == 0 ) { /* It's the default value, which is reported as an empty string, * so there's nothing to do. */ goto exit; } buflen = mbedtls_mpi_size( &mpi ); buffer = mbedtls_calloc( 1, buflen ); if( buffer == NULL ) { ret = MBEDTLS_ERR_MPI_ALLOC_FAILED; goto exit; } ret = mbedtls_mpi_write_binary( &mpi, buffer, buflen ); if( ret != 0 ) goto exit; attributes->domain_parameters = buffer; attributes->domain_parameters_size = buflen; exit: mbedtls_mpi_free( &mpi ); if( ret != 0 ) mbedtls_free( buffer ); return( mbedtls_to_psa_error( ret ) ); } #endif /* defined(MBEDTLS_PSA_BUILTIN_KEY_TYPE_RSA_KEY_PAIR) || * defined(MBEDTLS_PSA_BUILTIN_KEY_TYPE_RSA_PUBLIC_KEY) */ /** Retrieve all the publicly-accessible attributes of a key. */ psa_status_t psa_get_key_attributes( mbedtls_svc_key_id_t key, psa_key_attributes_t *attributes ) { psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED; psa_status_t unlock_status = PSA_ERROR_CORRUPTION_DETECTED; psa_key_slot_t *slot; psa_reset_key_attributes( attributes ); status = psa_get_and_lock_key_slot_with_policy( key, &slot, 0, 0 ); if( status != PSA_SUCCESS ) return( status ); attributes->core = slot->attr; attributes->core.flags &= ( MBEDTLS_PSA_KA_MASK_EXTERNAL_ONLY | MBEDTLS_PSA_KA_MASK_DUAL_USE ); #if defined(MBEDTLS_PSA_CRYPTO_SE_C) if( psa_get_se_driver_entry( slot->attr.lifetime ) != NULL ) psa_set_key_slot_number( attributes, psa_key_slot_get_slot_number( slot ) ); #endif /* MBEDTLS_PSA_CRYPTO_SE_C */ switch( slot->attr.type ) { #if defined(MBEDTLS_PSA_BUILTIN_KEY_TYPE_RSA_KEY_PAIR) || \ defined(MBEDTLS_PSA_BUILTIN_KEY_TYPE_RSA_PUBLIC_KEY) case PSA_KEY_TYPE_RSA_KEY_PAIR: case PSA_KEY_TYPE_RSA_PUBLIC_KEY: /* TODO: reporting the public exponent for opaque keys * is not yet implemented. * https://github.com/ARMmbed/mbed-crypto/issues/216 */ if( ! psa_key_lifetime_is_external( slot->attr.lifetime ) ) { mbedtls_rsa_context *rsa = NULL; status = mbedtls_psa_rsa_load_representation( slot->attr.type, slot->key.data, slot->key.bytes, &rsa ); if( status != PSA_SUCCESS ) break; status = psa_get_rsa_public_exponent( rsa, attributes ); mbedtls_rsa_free( rsa ); mbedtls_free( rsa ); } break; #endif /* defined(MBEDTLS_PSA_BUILTIN_KEY_TYPE_RSA_KEY_PAIR) || * defined(MBEDTLS_PSA_BUILTIN_KEY_TYPE_RSA_PUBLIC_KEY) */ default: /* Nothing else to do. */ break; } if( status != PSA_SUCCESS ) psa_reset_key_attributes( attributes ); unlock_status = psa_unlock_key_slot( slot ); return( ( status == PSA_SUCCESS ) ? unlock_status : status ); } #if defined(MBEDTLS_PSA_CRYPTO_SE_C) psa_status_t psa_get_key_slot_number( const psa_key_attributes_t *attributes, psa_key_slot_number_t *slot_number ) { if( attributes->core.flags & MBEDTLS_PSA_KA_FLAG_HAS_SLOT_NUMBER ) { *slot_number = attributes->slot_number; return( PSA_SUCCESS ); } else return( PSA_ERROR_INVALID_ARGUMENT ); } #endif /* MBEDTLS_PSA_CRYPTO_SE_C */ static psa_status_t psa_export_key_buffer_internal( const uint8_t *key_buffer, size_t key_buffer_size, uint8_t *data, size_t data_size, size_t *data_length ) { if( key_buffer_size > data_size ) return( PSA_ERROR_BUFFER_TOO_SMALL ); memcpy( data, key_buffer, key_buffer_size ); memset( data + key_buffer_size, 0, data_size - key_buffer_size ); *data_length = key_buffer_size; return( PSA_SUCCESS ); } psa_status_t psa_export_key_internal( 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_key_type_t type = attributes->core.type; if( key_type_is_raw_bytes( type ) || PSA_KEY_TYPE_IS_RSA( type ) || PSA_KEY_TYPE_IS_ECC( type ) ) { return( psa_export_key_buffer_internal( key_buffer, key_buffer_size, data, data_size, data_length ) ); } else { /* This shouldn't happen in the reference implementation, but it is valid for a special-purpose implementation to omit support for exporting certain key types. */ return( PSA_ERROR_NOT_SUPPORTED ); } } psa_status_t psa_export_key( mbedtls_svc_key_id_t key, uint8_t *data, size_t data_size, size_t *data_length ) { psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED; psa_status_t unlock_status = PSA_ERROR_CORRUPTION_DETECTED; psa_key_slot_t *slot; /* Reject a zero-length output buffer now, since this can never be a * valid key representation. This way we know that data must be a valid * pointer and we can do things like memset(data, ..., data_size). */ if( data_size == 0 ) return( PSA_ERROR_BUFFER_TOO_SMALL ); /* Set the key to empty now, so that even when there are errors, we always * set data_length to a value between 0 and data_size. On error, setting * the key to empty is a good choice because an empty key representation is * unlikely to be accepted anywhere. */ *data_length = 0; /* Export requires the EXPORT flag. There is an exception for public keys, * which don't require any flag, but * psa_get_and_lock_key_slot_with_policy() takes care of this. */ status = psa_get_and_lock_key_slot_with_policy( key, &slot, PSA_KEY_USAGE_EXPORT, 0 ); if( status != PSA_SUCCESS ) return( status ); psa_key_attributes_t attributes = { .core = slot->attr }; status = psa_driver_wrapper_export_key( &attributes, slot->key.data, slot->key.bytes, data, data_size, data_length ); unlock_status = psa_unlock_key_slot( slot ); return( ( status == PSA_SUCCESS ) ? unlock_status : status ); } psa_status_t psa_export_public_key_internal( 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_key_type_t type = attributes->core.type; if( PSA_KEY_TYPE_IS_RSA( type ) || PSA_KEY_TYPE_IS_ECC( type ) ) { if( PSA_KEY_TYPE_IS_PUBLIC_KEY( type ) ) { /* Exporting public -> public */ return( psa_export_key_buffer_internal( key_buffer, key_buffer_size, data, data_size, data_length ) ); } if( PSA_KEY_TYPE_IS_RSA( type ) ) { #if defined(MBEDTLS_PSA_BUILTIN_KEY_TYPE_RSA_KEY_PAIR) || \ defined(MBEDTLS_PSA_BUILTIN_KEY_TYPE_RSA_PUBLIC_KEY) return( mbedtls_psa_rsa_export_public_key( attributes, key_buffer, key_buffer_size, data, data_size, data_length ) ); #else /* We don't know how to convert a private RSA key to public. */ return( PSA_ERROR_NOT_SUPPORTED ); #endif /* defined(MBEDTLS_PSA_BUILTIN_KEY_TYPE_RSA_KEY_PAIR) || * defined(MBEDTLS_PSA_BUILTIN_KEY_TYPE_RSA_PUBLIC_KEY) */ } else { #if defined(MBEDTLS_PSA_BUILTIN_KEY_TYPE_ECC_KEY_PAIR) || \ defined(MBEDTLS_PSA_BUILTIN_KEY_TYPE_ECC_PUBLIC_KEY) return( mbedtls_psa_ecp_export_public_key( attributes, key_buffer, key_buffer_size, data, data_size, data_length ) ); #else /* We don't know how to convert a private ECC key to public */ return( PSA_ERROR_NOT_SUPPORTED ); #endif /* defined(MBEDTLS_PSA_BUILTIN_KEY_TYPE_ECC_KEY_PAIR) || * defined(MBEDTLS_PSA_BUILTIN_KEY_TYPE_ECC_PUBLIC_KEY) */ } } else { /* This shouldn't happen in the reference implementation, but it is valid for a special-purpose implementation to omit support for exporting certain key types. */ return( PSA_ERROR_NOT_SUPPORTED ); } } psa_status_t psa_export_public_key( mbedtls_svc_key_id_t key, uint8_t *data, size_t data_size, size_t *data_length ) { psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED; psa_status_t unlock_status = PSA_ERROR_CORRUPTION_DETECTED; psa_key_slot_t *slot; /* Reject a zero-length output buffer now, since this can never be a * valid key representation. This way we know that data must be a valid * pointer and we can do things like memset(data, ..., data_size). */ if( data_size == 0 ) return( PSA_ERROR_BUFFER_TOO_SMALL ); /* Set the key to empty now, so that even when there are errors, we always * set data_length to a value between 0 and data_size. On error, setting * the key to empty is a good choice because an empty key representation is * unlikely to be accepted anywhere. */ *data_length = 0; /* Exporting a public key doesn't require a usage flag. */ status = psa_get_and_lock_key_slot_with_policy( key, &slot, 0, 0 ); if( status != PSA_SUCCESS ) return( status ); if( ! PSA_KEY_TYPE_IS_ASYMMETRIC( slot->attr.type ) ) { status = PSA_ERROR_INVALID_ARGUMENT; goto exit; } psa_key_attributes_t attributes = { .core = slot->attr }; status = psa_driver_wrapper_export_public_key( &attributes, slot->key.data, slot->key.bytes, data, data_size, data_length ); exit: unlock_status = psa_unlock_key_slot( slot ); return( ( status == PSA_SUCCESS ) ? unlock_status : status ); } #if defined(static_assert) static_assert( ( MBEDTLS_PSA_KA_MASK_EXTERNAL_ONLY & MBEDTLS_PSA_KA_MASK_DUAL_USE ) == 0, "One or more key attribute flag is listed as both external-only and dual-use" ); static_assert( ( PSA_KA_MASK_INTERNAL_ONLY & MBEDTLS_PSA_KA_MASK_DUAL_USE ) == 0, "One or more key attribute flag is listed as both internal-only and dual-use" ); static_assert( ( PSA_KA_MASK_INTERNAL_ONLY & MBEDTLS_PSA_KA_MASK_EXTERNAL_ONLY ) == 0, "One or more key attribute flag is listed as both internal-only and external-only" ); #endif /** Validate that a key policy is internally well-formed. * * This function only rejects invalid policies. It does not validate the * consistency of the policy with respect to other attributes of the key * such as the key type. */ static psa_status_t psa_validate_key_policy( const psa_key_policy_t *policy ) { if( ( policy->usage & ~( PSA_KEY_USAGE_EXPORT | PSA_KEY_USAGE_COPY | PSA_KEY_USAGE_ENCRYPT | PSA_KEY_USAGE_DECRYPT | PSA_KEY_USAGE_SIGN_MESSAGE | PSA_KEY_USAGE_VERIFY_MESSAGE | PSA_KEY_USAGE_SIGN_HASH | PSA_KEY_USAGE_VERIFY_HASH | PSA_KEY_USAGE_VERIFY_DERIVATION | PSA_KEY_USAGE_DERIVE ) ) != 0 ) return( PSA_ERROR_INVALID_ARGUMENT ); return( PSA_SUCCESS ); } /** Validate the internal consistency of key attributes. * * This function only rejects invalid attribute values. If does not * validate the consistency of the attributes with any key data that may * be involved in the creation of the key. * * Call this function early in the key creation process. * * \param[in] attributes Key attributes for the new key. * \param[out] p_drv On any return, the driver for the key, if any. * NULL for a transparent key. * */ static psa_status_t psa_validate_key_attributes( const psa_key_attributes_t *attributes, psa_se_drv_table_entry_t **p_drv ) { psa_status_t status = PSA_ERROR_INVALID_ARGUMENT; psa_key_lifetime_t lifetime = psa_get_key_lifetime( attributes ); mbedtls_svc_key_id_t key = psa_get_key_id( attributes ); status = psa_validate_key_location( lifetime, p_drv ); if( status != PSA_SUCCESS ) return( status ); status = psa_validate_key_persistence( lifetime ); if( status != PSA_SUCCESS ) return( status ); if ( PSA_KEY_LIFETIME_IS_VOLATILE( lifetime ) ) { if( MBEDTLS_SVC_KEY_ID_GET_KEY_ID( key ) != 0 ) return( PSA_ERROR_INVALID_ARGUMENT ); } else { if( !psa_is_valid_key_id( psa_get_key_id( attributes ), 0 ) ) return( PSA_ERROR_INVALID_ARGUMENT ); } status = psa_validate_key_policy( &attributes->core.policy ); if( status != PSA_SUCCESS ) return( status ); /* Refuse to create overly large keys. * Note that this doesn't trigger on import if the attributes don't * explicitly specify a size (so psa_get_key_bits returns 0), so * psa_import_key() needs its own checks. */ if( psa_get_key_bits( attributes ) > PSA_MAX_KEY_BITS ) return( PSA_ERROR_NOT_SUPPORTED ); /* Reject invalid flags. These should not be reachable through the API. */ if( attributes->core.flags & ~ ( MBEDTLS_PSA_KA_MASK_EXTERNAL_ONLY | MBEDTLS_PSA_KA_MASK_DUAL_USE ) ) return( PSA_ERROR_INVALID_ARGUMENT ); return( PSA_SUCCESS ); } /** Prepare a key slot to receive key material. * * This function allocates a key slot and sets its metadata. * * If this function fails, call psa_fail_key_creation(). * * This function is intended to be used as follows: * -# Call psa_start_key_creation() to allocate a key slot, prepare * it with the specified attributes, and in case of a volatile key assign it * a volatile key identifier. * -# Populate the slot with the key material. * -# Call psa_finish_key_creation() to finalize the creation of the slot. * In case of failure at any step, stop the sequence and call * psa_fail_key_creation(). * * On success, the key slot is locked. It is the responsibility of the caller * to unlock the key slot when it does not access it anymore. * * \param method An identification of the calling function. * \param[in] attributes Key attributes for the new key. * \param[out] p_slot On success, a pointer to the prepared slot. * \param[out] p_drv On any return, the driver for the key, if any. * NULL for a transparent key. * * \retval #PSA_SUCCESS * The key slot is ready to receive key material. * \return If this function fails, the key slot is an invalid state. * You must call psa_fail_key_creation() to wipe and free the slot. */ static psa_status_t psa_start_key_creation( psa_key_creation_method_t method, const psa_key_attributes_t *attributes, psa_key_slot_t **p_slot, psa_se_drv_table_entry_t **p_drv ) { psa_status_t status; psa_key_id_t volatile_key_id; psa_key_slot_t *slot; (void) method; *p_drv = NULL; status = psa_validate_key_attributes( attributes, p_drv ); if( status != PSA_SUCCESS ) return( status ); status = psa_get_empty_key_slot( &volatile_key_id, p_slot ); if( status != PSA_SUCCESS ) return( status ); slot = *p_slot; /* We're storing the declared bit-size of the key. It's up to each * creation mechanism to verify that this information is correct. * It's automatically correct for mechanisms that use the bit-size as * an input (generate, device) but not for those where the bit-size * is optional (import, copy). In case of a volatile key, assign it the * volatile key identifier associated to the slot returned to contain its * definition. */ slot->attr = attributes->core; if( PSA_KEY_LIFETIME_IS_VOLATILE( slot->attr.lifetime ) ) { #if !defined(MBEDTLS_PSA_CRYPTO_KEY_ID_ENCODES_OWNER) slot->attr.id = volatile_key_id; #else slot->attr.id.key_id = volatile_key_id; #endif } /* Erase external-only flags from the internal copy. To access * external-only flags, query `attributes`. Thanks to the check * in psa_validate_key_attributes(), this leaves the dual-use * flags and any internal flag that psa_get_empty_key_slot() * may have set. */ slot->attr.flags &= ~MBEDTLS_PSA_KA_MASK_EXTERNAL_ONLY; #if defined(MBEDTLS_PSA_CRYPTO_SE_C) /* For a key in a secure element, we need to do three things * when creating or registering a persistent key: * create the key file in internal storage, create the * key inside the secure element, and update the driver's * persistent data. This is done by starting a transaction that will * encompass these three actions. * For registering a volatile key, we just need to find an appropriate * slot number inside the SE. Since the key is designated volatile, creating * a transaction is not required. */ /* The first thing to do is to find a slot number for the new key. * We save the slot number in persistent storage as part of the * transaction data. It will be needed to recover if the power * fails during the key creation process, to clean up on the secure * element side after restarting. Obtaining a slot number from the * secure element driver updates its persistent state, but we do not yet * save the driver's persistent state, so that if the power fails, * we can roll back to a state where the key doesn't exist. */ if( *p_drv != NULL ) { psa_key_slot_number_t slot_number; status = psa_find_se_slot_for_key( attributes, method, *p_drv, &slot_number ); if( status != PSA_SUCCESS ) return( status ); if( ! PSA_KEY_LIFETIME_IS_VOLATILE( attributes->core.lifetime ) ) { psa_crypto_prepare_transaction( PSA_CRYPTO_TRANSACTION_CREATE_KEY ); psa_crypto_transaction.key.lifetime = slot->attr.lifetime; psa_crypto_transaction.key.slot = slot_number; psa_crypto_transaction.key.id = slot->attr.id; status = psa_crypto_save_transaction( ); if( status != PSA_SUCCESS ) { (void) psa_crypto_stop_transaction( ); return( status ); } } status = psa_copy_key_material_into_slot( slot, (uint8_t *)( &slot_number ), sizeof( slot_number ) ); } if( *p_drv == NULL && method == PSA_KEY_CREATION_REGISTER ) { /* Key registration only makes sense with a secure element. */ return( PSA_ERROR_INVALID_ARGUMENT ); } #endif /* MBEDTLS_PSA_CRYPTO_SE_C */ return( PSA_SUCCESS ); } /** Finalize the creation of a key once its key material has been set. * * This entails writing the key to persistent storage. * * If this function fails, call psa_fail_key_creation(). * See the documentation of psa_start_key_creation() for the intended use * of this function. * * If the finalization succeeds, the function unlocks the key slot (it was * locked by psa_start_key_creation()) and the key slot cannot be accessed * anymore as part of the key creation process. * * \param[in,out] slot Pointer to the slot with key material. * \param[in] driver The secure element driver for the key, * or NULL for a transparent key. * \param[out] key On success, identifier of the key. Note that the * key identifier is also stored in the key slot. * * \retval #PSA_SUCCESS * The key was successfully created. * \retval #PSA_ERROR_INSUFFICIENT_MEMORY * \retval #PSA_ERROR_INSUFFICIENT_STORAGE * \retval #PSA_ERROR_ALREADY_EXISTS * \retval #PSA_ERROR_DATA_INVALID * \retval #PSA_ERROR_DATA_CORRUPT * \retval #PSA_ERROR_STORAGE_FAILURE * * \return If this function fails, the key slot is an invalid state. * You must call psa_fail_key_creation() to wipe and free the slot. */ static psa_status_t psa_finish_key_creation( psa_key_slot_t *slot, psa_se_drv_table_entry_t *driver, mbedtls_svc_key_id_t *key) { psa_status_t status = PSA_SUCCESS; (void) slot; (void) driver; #if defined(MBEDTLS_PSA_CRYPTO_STORAGE_C) if( ! PSA_KEY_LIFETIME_IS_VOLATILE( slot->attr.lifetime ) ) { #if defined(MBEDTLS_PSA_CRYPTO_SE_C) if( driver != NULL ) { psa_se_key_data_storage_t data; psa_key_slot_number_t slot_number = psa_key_slot_get_slot_number( slot ) ; #if defined(static_assert) static_assert( sizeof( slot_number ) == sizeof( data.slot_number ), "Slot number size does not match psa_se_key_data_storage_t" ); #endif memcpy( &data.slot_number, &slot_number, sizeof( slot_number ) ); status = psa_save_persistent_key( &slot->attr, (uint8_t*) &data, sizeof( data ) ); } else #endif /* MBEDTLS_PSA_CRYPTO_SE_C */ { /* Key material is saved in export representation in the slot, so * just pass the slot buffer for storage. */ status = psa_save_persistent_key( &slot->attr, slot->key.data, slot->key.bytes ); } } #endif /* defined(MBEDTLS_PSA_CRYPTO_STORAGE_C) */ #if defined(MBEDTLS_PSA_CRYPTO_SE_C) /* Finish the transaction for a key creation. This does not * happen when registering an existing key. Detect this case * by checking whether a transaction is in progress (actual * creation of a persistent key in a secure element requires a transaction, * but registration or volatile key creation doesn't use one). */ if( driver != NULL && psa_crypto_transaction.unknown.type == PSA_CRYPTO_TRANSACTION_CREATE_KEY ) { status = psa_save_se_persistent_data( driver ); if( status != PSA_SUCCESS ) { psa_destroy_persistent_key( slot->attr.id ); return( status ); } status = psa_crypto_stop_transaction( ); } #endif /* MBEDTLS_PSA_CRYPTO_SE_C */ if( status == PSA_SUCCESS ) { *key = slot->attr.id; status = psa_unlock_key_slot( slot ); if( status != PSA_SUCCESS ) *key = MBEDTLS_SVC_KEY_ID_INIT; } return( status ); } /** Abort the creation of a key. * * You may call this function after calling psa_start_key_creation(), * or after psa_finish_key_creation() fails. In other circumstances, this * function may not clean up persistent storage. * See the documentation of psa_start_key_creation() for the intended use * of this function. * * \param[in,out] slot Pointer to the slot with key material. * \param[in] driver The secure element driver for the key, * or NULL for a transparent key. */ static void psa_fail_key_creation( psa_key_slot_t *slot, psa_se_drv_table_entry_t *driver ) { (void) driver; if( slot == NULL ) return; #if defined(MBEDTLS_PSA_CRYPTO_SE_C) /* TODO: If the key has already been created in the secure * element, and the failure happened later (when saving metadata * to internal storage), we need to destroy the key in the secure * element. * https://github.com/ARMmbed/mbed-crypto/issues/217 */ /* Abort the ongoing transaction if any (there may not be one if * the creation process failed before starting one, or if the * key creation is a registration of a key in a secure element). * Earlier functions must already have done what it takes to undo any * partial creation. All that's left is to update the transaction data * itself. */ (void) psa_crypto_stop_transaction( ); #endif /* MBEDTLS_PSA_CRYPTO_SE_C */ psa_wipe_key_slot( slot ); } /** Validate optional attributes during key creation. * * Some key attributes are optional during key creation. If they are * specified in the attributes structure, check that they are consistent * with the data in the slot. * * This function should be called near the end of key creation, after * the slot in memory is fully populated but before saving persistent data. */ static psa_status_t psa_validate_optional_attributes( const psa_key_slot_t *slot, const psa_key_attributes_t *attributes ) { if( attributes->core.type != 0 ) { if( attributes->core.type != slot->attr.type ) return( PSA_ERROR_INVALID_ARGUMENT ); } if( attributes->domain_parameters_size != 0 ) { #if defined(MBEDTLS_PSA_BUILTIN_KEY_TYPE_RSA_KEY_PAIR) || \ defined(MBEDTLS_PSA_BUILTIN_KEY_TYPE_RSA_PUBLIC_KEY) if( PSA_KEY_TYPE_IS_RSA( slot->attr.type ) ) { mbedtls_rsa_context *rsa = NULL; mbedtls_mpi actual, required; int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; psa_status_t status = mbedtls_psa_rsa_load_representation( slot->attr.type, slot->key.data, slot->key.bytes, &rsa ); if( status != PSA_SUCCESS ) return( status ); mbedtls_mpi_init( &actual ); mbedtls_mpi_init( &required ); ret = mbedtls_rsa_export( rsa, NULL, NULL, NULL, NULL, &actual ); mbedtls_rsa_free( rsa ); mbedtls_free( rsa ); if( ret != 0 ) goto rsa_exit; ret = mbedtls_mpi_read_binary( &required, attributes->domain_parameters, attributes->domain_parameters_size ); if( ret != 0 ) goto rsa_exit; if( mbedtls_mpi_cmp_mpi( &actual, &required ) != 0 ) ret = MBEDTLS_ERR_RSA_BAD_INPUT_DATA; rsa_exit: mbedtls_mpi_free( &actual ); mbedtls_mpi_free( &required ); if( ret != 0) return( mbedtls_to_psa_error( ret ) ); } else #endif /* defined(MBEDTLS_PSA_BUILTIN_KEY_TYPE_RSA_KEY_PAIR) || * defined(MBEDTLS_PSA_BUILTIN_KEY_TYPE_RSA_PUBLIC_KEY) */ { return( PSA_ERROR_INVALID_ARGUMENT ); } } if( attributes->core.bits != 0 ) { if( attributes->core.bits != slot->attr.bits ) return( PSA_ERROR_INVALID_ARGUMENT ); } return( PSA_SUCCESS ); } psa_status_t psa_import_key( const psa_key_attributes_t *attributes, const uint8_t *data, size_t data_length, mbedtls_svc_key_id_t *key ) { psa_status_t status; psa_key_slot_t *slot = NULL; psa_se_drv_table_entry_t *driver = NULL; size_t bits; size_t storage_size = data_length; *key = MBEDTLS_SVC_KEY_ID_INIT; /* Reject zero-length symmetric keys (including raw data key objects). * This also rejects any key which might be encoded as an empty string, * which is never valid. */ if( data_length == 0 ) return( PSA_ERROR_INVALID_ARGUMENT ); /* Ensure that the bytes-to-bits conversion cannot overflow. */ if( data_length > SIZE_MAX / 8 ) return( PSA_ERROR_NOT_SUPPORTED ); status = psa_start_key_creation( PSA_KEY_CREATION_IMPORT, attributes, &slot, &driver ); if( status != PSA_SUCCESS ) goto exit; /* In the case of a transparent key or an opaque key stored in local * storage ( thus not in the case of importing a key in a secure element * with storage ( MBEDTLS_PSA_CRYPTO_SE_C ) ),we have to allocate a * buffer to hold the imported key material. */ if( slot->key.data == NULL ) { if( psa_key_lifetime_is_external( attributes->core.lifetime ) ) { status = psa_driver_wrapper_get_key_buffer_size_from_key_data( attributes, data, data_length, &storage_size ); if( status != PSA_SUCCESS ) goto exit; } status = psa_allocate_buffer_to_slot( slot, storage_size ); if( status != PSA_SUCCESS ) goto exit; } bits = slot->attr.bits; status = psa_driver_wrapper_import_key( attributes, data, data_length, slot->key.data, slot->key.bytes, &slot->key.bytes, &bits ); if( status != PSA_SUCCESS ) goto exit; if( slot->attr.bits == 0 ) slot->attr.bits = (psa_key_bits_t) bits; else if( bits != slot->attr.bits ) { status = PSA_ERROR_INVALID_ARGUMENT; goto exit; } /* Enforce a size limit, and in particular ensure that the bit * size fits in its representation type.*/ if( bits > PSA_MAX_KEY_BITS ) { status = PSA_ERROR_NOT_SUPPORTED; goto exit; } status = psa_validate_optional_attributes( slot, attributes ); if( status != PSA_SUCCESS ) goto exit; status = psa_finish_key_creation( slot, driver, key ); exit: if( status != PSA_SUCCESS ) psa_fail_key_creation( slot, driver ); return( status ); } #if defined(MBEDTLS_PSA_CRYPTO_SE_C) psa_status_t mbedtls_psa_register_se_key( const psa_key_attributes_t *attributes ) { psa_status_t status; psa_key_slot_t *slot = NULL; psa_se_drv_table_entry_t *driver = NULL; mbedtls_svc_key_id_t key = MBEDTLS_SVC_KEY_ID_INIT; /* Leaving attributes unspecified is not currently supported. * It could make sense to query the key type and size from the * secure element, but not all secure elements support this * and the driver HAL doesn't currently support it. */ if( psa_get_key_type( attributes ) == PSA_KEY_TYPE_NONE ) return( PSA_ERROR_NOT_SUPPORTED ); if( psa_get_key_bits( attributes ) == 0 ) return( PSA_ERROR_NOT_SUPPORTED ); status = psa_start_key_creation( PSA_KEY_CREATION_REGISTER, attributes, &slot, &driver ); if( status != PSA_SUCCESS ) goto exit; status = psa_finish_key_creation( slot, driver, &key ); exit: if( status != PSA_SUCCESS ) psa_fail_key_creation( slot, driver ); /* Registration doesn't keep the key in RAM. */ psa_close_key( key ); return( status ); } #endif /* MBEDTLS_PSA_CRYPTO_SE_C */ psa_status_t psa_copy_key( mbedtls_svc_key_id_t source_key, const psa_key_attributes_t *specified_attributes, mbedtls_svc_key_id_t *target_key ) { psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED; psa_status_t unlock_status = PSA_ERROR_CORRUPTION_DETECTED; psa_key_slot_t *source_slot = NULL; psa_key_slot_t *target_slot = NULL; psa_key_attributes_t actual_attributes = *specified_attributes; psa_se_drv_table_entry_t *driver = NULL; size_t storage_size = 0; *target_key = MBEDTLS_SVC_KEY_ID_INIT; status = psa_get_and_lock_key_slot_with_policy( source_key, &source_slot, PSA_KEY_USAGE_COPY, 0 ); if( status != PSA_SUCCESS ) goto exit; status = psa_validate_optional_attributes( source_slot, specified_attributes ); if( status != PSA_SUCCESS ) goto exit; /* The target key type and number of bits have been validated by * psa_validate_optional_attributes() to be either equal to zero or * equal to the ones of the source key. So it is safe to inherit * them from the source key now." * */ actual_attributes.core.bits = source_slot->attr.bits; actual_attributes.core.type = source_slot->attr.type; status = psa_restrict_key_policy( source_slot->attr.type, &actual_attributes.core.policy, &source_slot->attr.policy ); if( status != PSA_SUCCESS ) goto exit; status = psa_start_key_creation( PSA_KEY_CREATION_COPY, &actual_attributes, &target_slot, &driver ); if( status != PSA_SUCCESS ) goto exit; if( PSA_KEY_LIFETIME_GET_LOCATION( target_slot->attr.lifetime ) != PSA_KEY_LIFETIME_GET_LOCATION( source_slot->attr.lifetime ) ) { /* * If the source and target keys are stored in different locations, * the source key would need to be exported as plaintext and re-imported * in the other location. This has security implications which have not * been fully mapped. For now, this can be achieved through * appropriate API invocations from the application, if needed. * */ status = PSA_ERROR_NOT_SUPPORTED; goto exit; } /* * When the source and target keys are within the same location, * - For transparent keys it is a blind copy without any driver invocation, * - For opaque keys this translates to an invocation of the drivers' * copy_key entry point through the dispatch layer. * */ if( psa_key_lifetime_is_external( actual_attributes.core.lifetime ) ) { status = psa_driver_wrapper_get_key_buffer_size( &actual_attributes, &storage_size ); if( status != PSA_SUCCESS ) goto exit; status = psa_allocate_buffer_to_slot( target_slot, storage_size ); if( status != PSA_SUCCESS ) goto exit; status = psa_driver_wrapper_copy_key( &actual_attributes, source_slot->key.data, source_slot->key.bytes, target_slot->key.data, target_slot->key.bytes, &target_slot->key.bytes ); if( status != PSA_SUCCESS ) goto exit; } else { status = psa_copy_key_material_into_slot( target_slot, source_slot->key.data, source_slot->key.bytes ); if( status != PSA_SUCCESS ) goto exit; } status = psa_finish_key_creation( target_slot, driver, target_key ); exit: if( status != PSA_SUCCESS ) psa_fail_key_creation( target_slot, driver ); unlock_status = psa_unlock_key_slot( source_slot ); return( ( status == PSA_SUCCESS ) ? unlock_status : status ); } /****************************************************************/ /* Message digests */ /****************************************************************/ psa_status_t psa_hash_abort( psa_hash_operation_t *operation ) { /* Aborting a non-active operation is allowed */ if( operation->id == 0 ) return( PSA_SUCCESS ); psa_status_t status = psa_driver_wrapper_hash_abort( operation ); operation->id = 0; return( status ); } psa_status_t psa_hash_setup( psa_hash_operation_t *operation, psa_algorithm_t alg ) { psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED; /* A context must be freshly initialized before it can be set up. */ if( operation->id != 0 ) { status = PSA_ERROR_BAD_STATE; goto exit; } if( !PSA_ALG_IS_HASH( alg ) ) { status = PSA_ERROR_INVALID_ARGUMENT; goto exit; } /* Ensure all of the context is zeroized, since PSA_HASH_OPERATION_INIT only * directly zeroes the int-sized dummy member of the context union. */ memset( &operation->ctx, 0, sizeof( operation->ctx ) ); status = psa_driver_wrapper_hash_setup( operation, alg ); exit: if( status != PSA_SUCCESS ) psa_hash_abort( operation ); return status; } psa_status_t psa_hash_update( psa_hash_operation_t *operation, const uint8_t *input, size_t input_length ) { psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED; if( operation->id == 0 ) { status = PSA_ERROR_BAD_STATE; goto exit; } /* Don't require hash implementations to behave correctly on a * zero-length input, which may have an invalid pointer. */ if( input_length == 0 ) return( PSA_SUCCESS ); status = psa_driver_wrapper_hash_update( operation, input, input_length ); exit: if( status != PSA_SUCCESS ) psa_hash_abort( operation ); return( status ); } psa_status_t psa_hash_finish( psa_hash_operation_t *operation, uint8_t *hash, size_t hash_size, size_t *hash_length ) { *hash_length = 0; if( operation->id == 0 ) return( PSA_ERROR_BAD_STATE ); psa_status_t status = psa_driver_wrapper_hash_finish( operation, hash, hash_size, hash_length ); psa_hash_abort( operation ); return( status ); } psa_status_t psa_hash_verify( psa_hash_operation_t *operation, const uint8_t *hash, size_t hash_length ) { uint8_t actual_hash[PSA_HASH_MAX_SIZE]; size_t actual_hash_length; psa_status_t status = psa_hash_finish( operation, actual_hash, sizeof( actual_hash ), &actual_hash_length ); if( status != PSA_SUCCESS ) goto exit; if( actual_hash_length != hash_length ) { status = PSA_ERROR_INVALID_SIGNATURE; goto exit; } if( mbedtls_psa_safer_memcmp( hash, actual_hash, actual_hash_length ) != 0 ) status = PSA_ERROR_INVALID_SIGNATURE; exit: mbedtls_platform_zeroize( actual_hash, sizeof( actual_hash ) ); if( status != PSA_SUCCESS ) psa_hash_abort(operation); return( status ); } psa_status_t psa_hash_compute( psa_algorithm_t alg, const uint8_t *input, size_t input_length, uint8_t *hash, size_t hash_size, size_t *hash_length ) { *hash_length = 0; if( !PSA_ALG_IS_HASH( alg ) ) return( PSA_ERROR_INVALID_ARGUMENT ); return( psa_driver_wrapper_hash_compute( alg, input, input_length, hash, hash_size, hash_length ) ); } psa_status_t psa_hash_compare( psa_algorithm_t alg, const uint8_t *input, size_t input_length, const uint8_t *hash, size_t hash_length ) { uint8_t actual_hash[PSA_HASH_MAX_SIZE]; size_t actual_hash_length; if( !PSA_ALG_IS_HASH( alg ) ) return( PSA_ERROR_INVALID_ARGUMENT ); psa_status_t status = psa_driver_wrapper_hash_compute( alg, input, input_length, actual_hash, sizeof(actual_hash), &actual_hash_length ); if( status != PSA_SUCCESS ) goto exit; if( actual_hash_length != hash_length ) { status = PSA_ERROR_INVALID_SIGNATURE; goto exit; } if( mbedtls_psa_safer_memcmp( hash, actual_hash, actual_hash_length ) != 0 ) status = PSA_ERROR_INVALID_SIGNATURE; exit: mbedtls_platform_zeroize( actual_hash, sizeof( actual_hash ) ); return( status ); } psa_status_t psa_hash_clone( const psa_hash_operation_t *source_operation, psa_hash_operation_t *target_operation ) { if( source_operation->id == 0 || target_operation->id != 0 ) { return( PSA_ERROR_BAD_STATE ); } psa_status_t status = psa_driver_wrapper_hash_clone( source_operation, target_operation ); if( status != PSA_SUCCESS ) psa_hash_abort( target_operation ); return( status ); } /****************************************************************/ /* MAC */ /****************************************************************/ psa_status_t psa_mac_abort( psa_mac_operation_t *operation ) { /* Aborting a non-active operation is allowed */ if( operation->id == 0 ) return( PSA_SUCCESS ); psa_status_t status = psa_driver_wrapper_mac_abort( operation ); operation->mac_size = 0; operation->is_sign = 0; operation->id = 0; return( status ); } static psa_status_t psa_mac_finalize_alg_and_key_validation( psa_algorithm_t alg, const psa_key_attributes_t *attributes, uint8_t *mac_size ) { psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED; psa_key_type_t key_type = psa_get_key_type( attributes ); size_t key_bits = psa_get_key_bits( attributes ); if( ! PSA_ALG_IS_MAC( alg ) ) return( PSA_ERROR_INVALID_ARGUMENT ); /* Validate the combination of key type and algorithm */ status = psa_mac_key_can_do( alg, key_type ); if( status != PSA_SUCCESS ) return( status ); /* Get the output length for the algorithm and key combination */ *mac_size = PSA_MAC_LENGTH( key_type, key_bits, alg ); if( *mac_size < 4 ) { /* A very short MAC is too short for security since it can be * brute-forced. Ancient protocols with 32-bit MACs do exist, * so we make this our minimum, even though 32 bits is still * too small for security. */ return( PSA_ERROR_NOT_SUPPORTED ); } if( *mac_size > PSA_MAC_LENGTH( key_type, key_bits, PSA_ALG_FULL_LENGTH_MAC( alg ) ) ) { /* It's impossible to "truncate" to a larger length than the full length * of the algorithm. */ return( PSA_ERROR_INVALID_ARGUMENT ); } if( *mac_size > PSA_MAC_MAX_SIZE ) { /* PSA_MAC_LENGTH returns the correct length even for a MAC algorithm * that is disabled in the compile-time configuration. The result can * therefore be larger than PSA_MAC_MAX_SIZE, which does take the * configuration into account. In this case, force a return of * PSA_ERROR_NOT_SUPPORTED here. Otherwise psa_mac_verify(), or * psa_mac_compute(mac_size=PSA_MAC_MAX_SIZE), would return * PSA_ERROR_BUFFER_TOO_SMALL for an unsupported algorithm whose MAC size * is larger than PSA_MAC_MAX_SIZE, which is misleading and which breaks * systematically generated tests. */ return( PSA_ERROR_NOT_SUPPORTED ); } return( PSA_SUCCESS ); } static psa_status_t psa_mac_setup( psa_mac_operation_t *operation, mbedtls_svc_key_id_t key, psa_algorithm_t alg, int is_sign ) { psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED; psa_status_t unlock_status = PSA_ERROR_CORRUPTION_DETECTED; psa_key_slot_t *slot = NULL; /* A context must be freshly initialized before it can be set up. */ if( operation->id != 0 ) { status = PSA_ERROR_BAD_STATE; goto exit; } status = psa_get_and_lock_key_slot_with_policy( key, &slot, is_sign ? PSA_KEY_USAGE_SIGN_MESSAGE : PSA_KEY_USAGE_VERIFY_MESSAGE, alg ); if( status != PSA_SUCCESS ) goto exit; psa_key_attributes_t attributes = { .core = slot->attr }; status = psa_mac_finalize_alg_and_key_validation( alg, &attributes, &operation->mac_size ); if( status != PSA_SUCCESS ) goto exit; operation->is_sign = is_sign; /* Dispatch the MAC setup call with validated input */ if( is_sign ) { status = psa_driver_wrapper_mac_sign_setup( operation, &attributes, slot->key.data, slot->key.bytes, alg ); } else { status = psa_driver_wrapper_mac_verify_setup( operation, &attributes, slot->key.data, slot->key.bytes, alg ); } exit: if( status != PSA_SUCCESS ) psa_mac_abort( operation ); unlock_status = psa_unlock_key_slot( slot ); return( ( status == PSA_SUCCESS ) ? unlock_status : status ); } psa_status_t psa_mac_sign_setup( psa_mac_operation_t *operation, mbedtls_svc_key_id_t key, psa_algorithm_t alg ) { return( psa_mac_setup( operation, key, alg, 1 ) ); } psa_status_t psa_mac_verify_setup( psa_mac_operation_t *operation, mbedtls_svc_key_id_t key, psa_algorithm_t alg ) { return( psa_mac_setup( operation, key, alg, 0 ) ); } psa_status_t psa_mac_update( psa_mac_operation_t *operation, const uint8_t *input, size_t input_length ) { if( operation->id == 0 ) return( PSA_ERROR_BAD_STATE ); /* Don't require hash implementations to behave correctly on a * zero-length input, which may have an invalid pointer. */ if( input_length == 0 ) return( PSA_SUCCESS ); psa_status_t status = psa_driver_wrapper_mac_update( operation, input, input_length ); if( status != PSA_SUCCESS ) psa_mac_abort( operation ); return( status ); } psa_status_t psa_mac_sign_finish( psa_mac_operation_t *operation, uint8_t *mac, size_t mac_size, size_t *mac_length ) { psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED; psa_status_t abort_status = PSA_ERROR_CORRUPTION_DETECTED; if( operation->id == 0 ) { status = PSA_ERROR_BAD_STATE; goto exit; } if( ! operation->is_sign ) { status = PSA_ERROR_BAD_STATE; goto exit; } /* Sanity check. This will guarantee that mac_size != 0 (and so mac != NULL) * once all the error checks are done. */ if( operation->mac_size == 0 ) { status = PSA_ERROR_BAD_STATE; goto exit; } if( mac_size < operation->mac_size ) { status = PSA_ERROR_BUFFER_TOO_SMALL; goto exit; } status = psa_driver_wrapper_mac_sign_finish( operation, mac, operation->mac_size, mac_length ); exit: /* In case of success, set the potential excess room in the output buffer * to an invalid value, to avoid potentially leaking a longer MAC. * In case of error, set the output length and content to a safe default, * such that in case the caller misses an error check, the output would be * an unachievable MAC. */ if( status != PSA_SUCCESS ) { *mac_length = mac_size; operation->mac_size = 0; } if( mac_size > operation->mac_size ) memset( &mac[operation->mac_size], '!', mac_size - operation->mac_size ); abort_status = psa_mac_abort( operation ); return( status == PSA_SUCCESS ? abort_status : status ); } psa_status_t psa_mac_verify_finish( psa_mac_operation_t *operation, const uint8_t *mac, size_t mac_length ) { psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED; psa_status_t abort_status = PSA_ERROR_CORRUPTION_DETECTED; if( operation->id == 0 ) { status = PSA_ERROR_BAD_STATE; goto exit; } if( operation->is_sign ) { status = PSA_ERROR_BAD_STATE; goto exit; } if( operation->mac_size != mac_length ) { status = PSA_ERROR_INVALID_SIGNATURE; goto exit; } status = psa_driver_wrapper_mac_verify_finish( operation, mac, mac_length ); exit: abort_status = psa_mac_abort( operation ); return( status == PSA_SUCCESS ? abort_status : status ); } static psa_status_t psa_mac_compute_internal( mbedtls_svc_key_id_t key, psa_algorithm_t alg, const uint8_t *input, size_t input_length, uint8_t *mac, size_t mac_size, size_t *mac_length, int is_sign ) { psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED; psa_status_t unlock_status = PSA_ERROR_CORRUPTION_DETECTED; psa_key_slot_t *slot; uint8_t operation_mac_size = 0; status = psa_get_and_lock_key_slot_with_policy( key, &slot, is_sign ? PSA_KEY_USAGE_SIGN_MESSAGE : PSA_KEY_USAGE_VERIFY_MESSAGE, alg ); if( status != PSA_SUCCESS ) goto exit; psa_key_attributes_t attributes = { .core = slot->attr }; status = psa_mac_finalize_alg_and_key_validation( alg, &attributes, &operation_mac_size ); if( status != PSA_SUCCESS ) goto exit; if( mac_size < operation_mac_size ) { status = PSA_ERROR_BUFFER_TOO_SMALL; goto exit; } status = psa_driver_wrapper_mac_compute( &attributes, slot->key.data, slot->key.bytes, alg, input, input_length, mac, operation_mac_size, mac_length ); exit: /* In case of success, set the potential excess room in the output buffer * to an invalid value, to avoid potentially leaking a longer MAC. * In case of error, set the output length and content to a safe default, * such that in case the caller misses an error check, the output would be * an unachievable MAC. */ if( status != PSA_SUCCESS ) { *mac_length = mac_size; operation_mac_size = 0; } if( mac_size > operation_mac_size ) memset( &mac[operation_mac_size], '!', mac_size - operation_mac_size ); unlock_status = psa_unlock_key_slot( slot ); return( ( status == PSA_SUCCESS ) ? unlock_status : status ); } psa_status_t psa_mac_compute( mbedtls_svc_key_id_t key, psa_algorithm_t alg, const uint8_t *input, size_t input_length, uint8_t *mac, size_t mac_size, size_t *mac_length) { return( psa_mac_compute_internal( key, alg, input, input_length, mac, mac_size, mac_length, 1 ) ); } psa_status_t psa_mac_verify( mbedtls_svc_key_id_t key, psa_algorithm_t alg, const uint8_t *input, size_t input_length, const uint8_t *mac, size_t mac_length) { psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED; uint8_t actual_mac[PSA_MAC_MAX_SIZE]; size_t actual_mac_length; status = psa_mac_compute_internal( key, alg, input, input_length, actual_mac, sizeof( actual_mac ), &actual_mac_length, 0 ); if( status != PSA_SUCCESS ) goto exit; if( mac_length != actual_mac_length ) { status = PSA_ERROR_INVALID_SIGNATURE; goto exit; } if( mbedtls_psa_safer_memcmp( mac, actual_mac, actual_mac_length ) != 0 ) { status = PSA_ERROR_INVALID_SIGNATURE; goto exit; } exit: mbedtls_platform_zeroize( actual_mac, sizeof( actual_mac ) ); return ( status ); } /****************************************************************/ /* Asymmetric cryptography */ /****************************************************************/ static psa_status_t psa_sign_verify_check_alg( int input_is_message, psa_algorithm_t alg ) { if( input_is_message ) { if( ! PSA_ALG_IS_SIGN_MESSAGE( alg ) ) return( PSA_ERROR_INVALID_ARGUMENT ); if ( PSA_ALG_IS_SIGN_HASH( alg ) ) { if( ! PSA_ALG_IS_HASH( PSA_ALG_SIGN_GET_HASH( alg ) ) ) return( PSA_ERROR_INVALID_ARGUMENT ); } } else { if( ! PSA_ALG_IS_SIGN_HASH( alg ) ) return( PSA_ERROR_INVALID_ARGUMENT ); } return( PSA_SUCCESS ); } static psa_status_t psa_sign_internal( mbedtls_svc_key_id_t key, int input_is_message, psa_algorithm_t alg, const uint8_t * input, size_t input_length, uint8_t * signature, size_t signature_size, size_t * signature_length ) { psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED; psa_status_t unlock_status = PSA_ERROR_CORRUPTION_DETECTED; psa_key_slot_t *slot; *signature_length = 0; status = psa_sign_verify_check_alg( input_is_message, alg ); if( status != PSA_SUCCESS ) return status; /* Immediately reject a zero-length signature buffer. This guarantees * that signature must be a valid pointer. (On the other hand, the input * buffer can in principle be empty since it doesn't actually have * to be a hash.) */ if( signature_size == 0 ) return( PSA_ERROR_BUFFER_TOO_SMALL ); status = psa_get_and_lock_key_slot_with_policy( key, &slot, input_is_message ? PSA_KEY_USAGE_SIGN_MESSAGE : PSA_KEY_USAGE_SIGN_HASH, alg ); if( status != PSA_SUCCESS ) goto exit; if( ! PSA_KEY_TYPE_IS_KEY_PAIR( slot->attr.type ) ) { status = PSA_ERROR_INVALID_ARGUMENT; goto exit; } psa_key_attributes_t attributes = { .core = slot->attr }; if( input_is_message ) { status = psa_driver_wrapper_sign_message( &attributes, slot->key.data, slot->key.bytes, alg, input, input_length, signature, signature_size, signature_length ); } else { status = psa_driver_wrapper_sign_hash( &attributes, slot->key.data, slot->key.bytes, alg, input, input_length, signature, signature_size, signature_length ); } exit: /* Fill the unused part of the output buffer (the whole buffer on error, * the trailing part on success) with something that isn't a valid signature * (barring an attack on the signature and deliberately-crafted input), * in case the caller doesn't check the return status properly. */ if( status == PSA_SUCCESS ) memset( signature + *signature_length, '!', signature_size - *signature_length ); else memset( signature, '!', signature_size ); /* If signature_size is 0 then we have nothing to do. We must not call * memset because signature may be NULL in this case. */ unlock_status = psa_unlock_key_slot( slot ); return( ( status == PSA_SUCCESS ) ? unlock_status : status ); } static psa_status_t psa_verify_internal( mbedtls_svc_key_id_t key, int input_is_message, psa_algorithm_t alg, const uint8_t * input, size_t input_length, const uint8_t * signature, size_t signature_length ) { psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED; psa_status_t unlock_status = PSA_ERROR_CORRUPTION_DETECTED; psa_key_slot_t *slot; status = psa_sign_verify_check_alg( input_is_message, alg ); if( status != PSA_SUCCESS ) return status; status = psa_get_and_lock_key_slot_with_policy( key, &slot, input_is_message ? PSA_KEY_USAGE_VERIFY_MESSAGE : PSA_KEY_USAGE_VERIFY_HASH, alg ); if( status != PSA_SUCCESS ) return( status ); psa_key_attributes_t attributes = { .core = slot->attr }; if( input_is_message ) { status = psa_driver_wrapper_verify_message( &attributes, slot->key.data, slot->key.bytes, alg, input, input_length, signature, signature_length ); } else { status = psa_driver_wrapper_verify_hash( &attributes, slot->key.data, slot->key.bytes, alg, input, input_length, signature, signature_length ); } unlock_status = psa_unlock_key_slot( slot ); return( ( status == PSA_SUCCESS ) ? unlock_status : status ); } psa_status_t psa_sign_message_builtin( const psa_key_attributes_t *attributes, const uint8_t *key_buffer, size_t key_buffer_size, psa_algorithm_t alg, const uint8_t *input, size_t input_length, uint8_t *signature, size_t signature_size, size_t *signature_length ) { psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED; if ( PSA_ALG_IS_SIGN_HASH( alg ) ) { size_t hash_length; uint8_t hash[PSA_HASH_MAX_SIZE]; status = psa_driver_wrapper_hash_compute( PSA_ALG_SIGN_GET_HASH( alg ), input, input_length, hash, sizeof( hash ), &hash_length ); if( status != PSA_SUCCESS ) return status; return psa_driver_wrapper_sign_hash( attributes, key_buffer, key_buffer_size, alg, hash, hash_length, signature, signature_size, signature_length ); } return( PSA_ERROR_NOT_SUPPORTED ); } psa_status_t psa_sign_message( mbedtls_svc_key_id_t key, psa_algorithm_t alg, const uint8_t * input, size_t input_length, uint8_t * signature, size_t signature_size, size_t * signature_length ) { return psa_sign_internal( key, 1, alg, input, input_length, signature, signature_size, signature_length ); } psa_status_t psa_verify_message_builtin( const psa_key_attributes_t *attributes, const uint8_t *key_buffer, size_t key_buffer_size, psa_algorithm_t alg, const uint8_t *input, size_t input_length, const uint8_t *signature, size_t signature_length ) { psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED; if ( PSA_ALG_IS_SIGN_HASH( alg ) ) { size_t hash_length; uint8_t hash[PSA_HASH_MAX_SIZE]; status = psa_driver_wrapper_hash_compute( PSA_ALG_SIGN_GET_HASH( alg ), input, input_length, hash, sizeof( hash ), &hash_length ); if( status != PSA_SUCCESS ) return status; return psa_driver_wrapper_verify_hash( attributes, key_buffer, key_buffer_size, alg, hash, hash_length, signature, signature_length ); } return( PSA_ERROR_NOT_SUPPORTED ); } psa_status_t psa_verify_message( mbedtls_svc_key_id_t key, psa_algorithm_t alg, const uint8_t * input, size_t input_length, const uint8_t * signature, size_t signature_length ) { return psa_verify_internal( key, 1, alg, input, input_length, signature, signature_length ); } psa_status_t psa_sign_hash_builtin( 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( attributes->core.type == PSA_KEY_TYPE_RSA_KEY_PAIR ) { if( PSA_ALG_IS_RSA_PKCS1V15_SIGN( alg ) || PSA_ALG_IS_RSA_PSS( alg) ) { #if defined(MBEDTLS_PSA_BUILTIN_ALG_RSA_PKCS1V15_SIGN) || \ defined(MBEDTLS_PSA_BUILTIN_ALG_RSA_PSS) return( mbedtls_psa_rsa_sign_hash( attributes, key_buffer, key_buffer_size, alg, hash, hash_length, signature, signature_size, signature_length ) ); #endif /* defined(MBEDTLS_PSA_BUILTIN_ALG_RSA_PKCS1V15_SIGN) || * defined(MBEDTLS_PSA_BUILTIN_ALG_RSA_PSS) */ } else { return( PSA_ERROR_INVALID_ARGUMENT ); } } else if( PSA_KEY_TYPE_IS_ECC( attributes->core.type ) ) { if( PSA_ALG_IS_ECDSA( alg ) ) { #if defined(MBEDTLS_PSA_BUILTIN_ALG_ECDSA) || \ defined(MBEDTLS_PSA_BUILTIN_ALG_DETERMINISTIC_ECDSA) return( mbedtls_psa_ecdsa_sign_hash( attributes, key_buffer, key_buffer_size, alg, hash, hash_length, signature, signature_size, signature_length ) ); #endif /* defined(MBEDTLS_PSA_BUILTIN_ALG_ECDSA) || * defined(MBEDTLS_PSA_BUILTIN_ALG_DETERMINISTIC_ECDSA) */ } else { return( PSA_ERROR_INVALID_ARGUMENT ); } } (void)key_buffer; (void)key_buffer_size; (void)hash; (void)hash_length; (void)signature; (void)signature_size; (void)signature_length; return( PSA_ERROR_NOT_SUPPORTED ); } psa_status_t psa_sign_hash( mbedtls_svc_key_id_t key, psa_algorithm_t alg, const uint8_t *hash, size_t hash_length, uint8_t *signature, size_t signature_size, size_t *signature_length ) { return psa_sign_internal( key, 0, alg, hash, hash_length, signature, signature_size, signature_length ); } psa_status_t psa_verify_hash_builtin( 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( PSA_KEY_TYPE_IS_RSA( attributes->core.type ) ) { if( PSA_ALG_IS_RSA_PKCS1V15_SIGN( alg ) || PSA_ALG_IS_RSA_PSS( alg) ) { #if defined(MBEDTLS_PSA_BUILTIN_ALG_RSA_PKCS1V15_SIGN) || \ defined(MBEDTLS_PSA_BUILTIN_ALG_RSA_PSS) return( mbedtls_psa_rsa_verify_hash( attributes, key_buffer, key_buffer_size, alg, hash, hash_length, signature, signature_length ) ); #endif /* defined(MBEDTLS_PSA_BUILTIN_ALG_RSA_PKCS1V15_SIGN) || * defined(MBEDTLS_PSA_BUILTIN_ALG_RSA_PSS) */ } else { return( PSA_ERROR_INVALID_ARGUMENT ); } } else if( PSA_KEY_TYPE_IS_ECC( attributes->core.type ) ) { if( PSA_ALG_IS_ECDSA( alg ) ) { #if defined(MBEDTLS_PSA_BUILTIN_ALG_ECDSA) || \ defined(MBEDTLS_PSA_BUILTIN_ALG_DETERMINISTIC_ECDSA) return( mbedtls_psa_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) */ } else { return( PSA_ERROR_INVALID_ARGUMENT ); } } (void)key_buffer; (void)key_buffer_size; (void)hash; (void)hash_length; (void)signature; (void)signature_length; return( PSA_ERROR_NOT_SUPPORTED ); } psa_status_t psa_verify_hash( mbedtls_svc_key_id_t key, psa_algorithm_t alg, const uint8_t *hash, size_t hash_length, const uint8_t *signature, size_t signature_length ) { return psa_verify_internal( key, 0, alg, hash, hash_length, signature, signature_length ); } psa_status_t psa_asymmetric_encrypt( mbedtls_svc_key_id_t key, psa_algorithm_t alg, const uint8_t *input, size_t input_length, const uint8_t *salt, size_t salt_length, uint8_t *output, size_t output_size, size_t *output_length ) { psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED; psa_status_t unlock_status = PSA_ERROR_CORRUPTION_DETECTED; psa_key_slot_t *slot; (void) input; (void) input_length; (void) salt; (void) output; (void) output_size; *output_length = 0; if( ! PSA_ALG_IS_RSA_OAEP( alg ) && salt_length != 0 ) return( PSA_ERROR_INVALID_ARGUMENT ); status = psa_get_and_lock_transparent_key_slot_with_policy( key, &slot, PSA_KEY_USAGE_ENCRYPT, alg ); if( status != PSA_SUCCESS ) return( status ); if( ! ( PSA_KEY_TYPE_IS_PUBLIC_KEY( slot->attr.type ) || PSA_KEY_TYPE_IS_KEY_PAIR( slot->attr.type ) ) ) { status = PSA_ERROR_INVALID_ARGUMENT; goto exit; } psa_key_attributes_t attributes = { .core = slot->attr }; status = psa_driver_wrapper_asymmetric_encrypt( &attributes, slot->key.data, slot->key.bytes, alg, input, input_length, salt, salt_length, output, output_size, output_length ); exit: unlock_status = psa_unlock_key_slot( slot ); return( ( status == PSA_SUCCESS ) ? unlock_status : status ); } psa_status_t psa_asymmetric_decrypt( mbedtls_svc_key_id_t key, psa_algorithm_t alg, const uint8_t *input, size_t input_length, const uint8_t *salt, size_t salt_length, uint8_t *output, size_t output_size, size_t *output_length ) { psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED; psa_status_t unlock_status = PSA_ERROR_CORRUPTION_DETECTED; psa_key_slot_t *slot; (void) input; (void) input_length; (void) salt; (void) output; (void) output_size; *output_length = 0; if( ! PSA_ALG_IS_RSA_OAEP( alg ) && salt_length != 0 ) return( PSA_ERROR_INVALID_ARGUMENT ); status = psa_get_and_lock_transparent_key_slot_with_policy( key, &slot, PSA_KEY_USAGE_DECRYPT, alg ); if( status != PSA_SUCCESS ) return( status ); if( ! PSA_KEY_TYPE_IS_KEY_PAIR( slot->attr.type ) ) { status = PSA_ERROR_INVALID_ARGUMENT; goto exit; } psa_key_attributes_t attributes = { .core = slot->attr }; status = psa_driver_wrapper_asymmetric_decrypt( &attributes, slot->key.data, slot->key.bytes, alg, input, input_length, salt, salt_length, output, output_size, output_length ); exit: unlock_status = psa_unlock_key_slot( slot ); return( ( status == PSA_SUCCESS ) ? unlock_status : status ); } /****************************************************************/ /* Symmetric cryptography */ /****************************************************************/ static psa_status_t psa_cipher_setup( psa_cipher_operation_t *operation, mbedtls_svc_key_id_t key, psa_algorithm_t alg, mbedtls_operation_t cipher_operation ) { psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED; psa_status_t unlock_status = PSA_ERROR_CORRUPTION_DETECTED; psa_key_slot_t *slot = NULL; psa_key_usage_t usage = ( cipher_operation == MBEDTLS_ENCRYPT ? PSA_KEY_USAGE_ENCRYPT : PSA_KEY_USAGE_DECRYPT ); /* A context must be freshly initialized before it can be set up. */ if( operation->id != 0 ) { status = PSA_ERROR_BAD_STATE; goto exit; } if( ! PSA_ALG_IS_CIPHER( alg ) ) { status = PSA_ERROR_INVALID_ARGUMENT; goto exit; } status = psa_get_and_lock_key_slot_with_policy( key, &slot, usage, alg ); if( status != PSA_SUCCESS ) goto exit; /* Initialize the operation struct members, except for id. The id member * is used to indicate to psa_cipher_abort that there are resources to free, * so we only set it (in the driver wrapper) after resources have been * allocated/initialized. */ operation->iv_set = 0; if( alg == PSA_ALG_ECB_NO_PADDING ) operation->iv_required = 0; else operation->iv_required = 1; operation->default_iv_length = PSA_CIPHER_IV_LENGTH( slot->attr.type, alg ); psa_key_attributes_t attributes = { .core = slot->attr }; /* Try doing the operation through a driver before using software fallback. */ if( cipher_operation == MBEDTLS_ENCRYPT ) status = psa_driver_wrapper_cipher_encrypt_setup( operation, &attributes, slot->key.data, slot->key.bytes, alg ); else status = psa_driver_wrapper_cipher_decrypt_setup( operation, &attributes, slot->key.data, slot->key.bytes, alg ); exit: if( status != PSA_SUCCESS ) psa_cipher_abort( operation ); unlock_status = psa_unlock_key_slot( slot ); return( ( status == PSA_SUCCESS ) ? unlock_status : status ); } psa_status_t psa_cipher_encrypt_setup( psa_cipher_operation_t *operation, mbedtls_svc_key_id_t key, psa_algorithm_t alg ) { return( psa_cipher_setup( operation, key, alg, MBEDTLS_ENCRYPT ) ); } psa_status_t psa_cipher_decrypt_setup( psa_cipher_operation_t *operation, mbedtls_svc_key_id_t key, psa_algorithm_t alg ) { return( psa_cipher_setup( operation, key, alg, MBEDTLS_DECRYPT ) ); } psa_status_t psa_cipher_generate_iv( psa_cipher_operation_t *operation, uint8_t *iv, size_t iv_size, size_t *iv_length ) { psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED; uint8_t local_iv[PSA_CIPHER_IV_MAX_SIZE]; size_t default_iv_length; if( operation->id == 0 ) { status = PSA_ERROR_BAD_STATE; goto exit; } if( operation->iv_set || ! operation->iv_required ) { status = PSA_ERROR_BAD_STATE; goto exit; } default_iv_length = operation->default_iv_length; if( iv_size < default_iv_length ) { status = PSA_ERROR_BUFFER_TOO_SMALL; goto exit; } if( default_iv_length > PSA_CIPHER_IV_MAX_SIZE ) { status = PSA_ERROR_GENERIC_ERROR; goto exit; } status = psa_generate_random( local_iv, default_iv_length ); if( status != PSA_SUCCESS ) goto exit; status = psa_driver_wrapper_cipher_set_iv( operation, local_iv, default_iv_length ); exit: if( status == PSA_SUCCESS ) { memcpy( iv, local_iv, default_iv_length ); *iv_length = default_iv_length; operation->iv_set = 1; } else { *iv_length = 0; psa_cipher_abort( operation ); } return( status ); } psa_status_t psa_cipher_set_iv( psa_cipher_operation_t *operation, const uint8_t *iv, size_t iv_length ) { psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED; if( operation->id == 0 ) { status = PSA_ERROR_BAD_STATE; goto exit; } if( operation->iv_set || ! operation->iv_required ) { status = PSA_ERROR_BAD_STATE; goto exit; } if( iv_length > PSA_CIPHER_IV_MAX_SIZE ) { status = PSA_ERROR_INVALID_ARGUMENT; goto exit; } status = psa_driver_wrapper_cipher_set_iv( operation, iv, iv_length ); exit: if( status == PSA_SUCCESS ) operation->iv_set = 1; else psa_cipher_abort( operation ); return( status ); } psa_status_t psa_cipher_update( psa_cipher_operation_t *operation, const uint8_t *input, size_t input_length, uint8_t *output, size_t output_size, size_t *output_length ) { psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED; if( operation->id == 0 ) { status = PSA_ERROR_BAD_STATE; goto exit; } if( operation->iv_required && ! operation->iv_set ) { status = PSA_ERROR_BAD_STATE; goto exit; } status = psa_driver_wrapper_cipher_update( operation, input, input_length, output, output_size, output_length ); exit: if( status != PSA_SUCCESS ) psa_cipher_abort( operation ); return( status ); } psa_status_t psa_cipher_finish( psa_cipher_operation_t *operation, uint8_t *output, size_t output_size, size_t *output_length ) { psa_status_t status = PSA_ERROR_GENERIC_ERROR; if( operation->id == 0 ) { status = PSA_ERROR_BAD_STATE; goto exit; } if( operation->iv_required && ! operation->iv_set ) { status = PSA_ERROR_BAD_STATE; goto exit; } status = psa_driver_wrapper_cipher_finish( operation, output, output_size, output_length ); exit: if( status == PSA_SUCCESS ) return( psa_cipher_abort( operation ) ); else { *output_length = 0; (void) psa_cipher_abort( operation ); return( status ); } } psa_status_t psa_cipher_abort( psa_cipher_operation_t *operation ) { if( operation->id == 0 ) { /* The object has (apparently) been initialized but it is not (yet) * in use. It's ok to call abort on such an object, and there's * nothing to do. */ return( PSA_SUCCESS ); } psa_driver_wrapper_cipher_abort( operation ); operation->id = 0; operation->iv_set = 0; operation->iv_required = 0; return( PSA_SUCCESS ); } psa_status_t psa_cipher_encrypt( mbedtls_svc_key_id_t key, psa_algorithm_t alg, const uint8_t *input, size_t input_length, uint8_t *output, size_t output_size, size_t *output_length ) { psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED; psa_status_t unlock_status = PSA_ERROR_CORRUPTION_DETECTED; psa_key_slot_t *slot = NULL; uint8_t local_iv[PSA_CIPHER_IV_MAX_SIZE]; size_t default_iv_length = 0; if( ! PSA_ALG_IS_CIPHER( alg ) ) { status = PSA_ERROR_INVALID_ARGUMENT; goto exit; } status = psa_get_and_lock_key_slot_with_policy( key, &slot, PSA_KEY_USAGE_ENCRYPT, alg ); if( status != PSA_SUCCESS ) goto exit; psa_key_attributes_t attributes = { .core = slot->attr }; default_iv_length = PSA_CIPHER_IV_LENGTH( slot->attr.type, alg ); if( default_iv_length > PSA_CIPHER_IV_MAX_SIZE ) { status = PSA_ERROR_GENERIC_ERROR; goto exit; } if( default_iv_length > 0 ) { if( output_size < default_iv_length ) { status = PSA_ERROR_BUFFER_TOO_SMALL; goto exit; } status = psa_generate_random( local_iv, default_iv_length ); if( status != PSA_SUCCESS ) goto exit; } status = psa_driver_wrapper_cipher_encrypt( &attributes, slot->key.data, slot->key.bytes, alg, local_iv, default_iv_length, input, input_length, output + default_iv_length, output_size - default_iv_length, output_length ); exit: unlock_status = psa_unlock_key_slot( slot ); if( status == PSA_SUCCESS ) status = unlock_status; if( status == PSA_SUCCESS ) { if( default_iv_length > 0 ) memcpy( output, local_iv, default_iv_length ); *output_length += default_iv_length; } else *output_length = 0; return( status ); } psa_status_t psa_cipher_decrypt( mbedtls_svc_key_id_t key, psa_algorithm_t alg, const uint8_t *input, size_t input_length, uint8_t *output, size_t output_size, size_t *output_length ) { psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED; psa_status_t unlock_status = PSA_ERROR_CORRUPTION_DETECTED; psa_key_slot_t *slot = NULL; if( ! PSA_ALG_IS_CIPHER( alg ) ) { status = PSA_ERROR_INVALID_ARGUMENT; goto exit; } status = psa_get_and_lock_key_slot_with_policy( key, &slot, PSA_KEY_USAGE_DECRYPT, alg ); if( status != PSA_SUCCESS ) goto exit; psa_key_attributes_t attributes = { .core = slot->attr }; if( alg == PSA_ALG_CCM_STAR_NO_TAG && input_length < PSA_BLOCK_CIPHER_BLOCK_LENGTH( slot->attr.type ) ) { status = PSA_ERROR_INVALID_ARGUMENT; goto exit; } else if ( input_length < PSA_CIPHER_IV_LENGTH( slot->attr.type, alg ) ) { status = PSA_ERROR_INVALID_ARGUMENT; goto exit; } status = psa_driver_wrapper_cipher_decrypt( &attributes, slot->key.data, slot->key.bytes, alg, input, input_length, output, output_size, output_length ); exit: unlock_status = psa_unlock_key_slot( slot ); if( status == PSA_SUCCESS ) status = unlock_status; if( status != PSA_SUCCESS ) *output_length = 0; return( status ); } /****************************************************************/ /* AEAD */ /****************************************************************/ /* Helper function to get the base algorithm from its variants. */ static psa_algorithm_t psa_aead_get_base_algorithm( psa_algorithm_t alg ) { return PSA_ALG_AEAD_WITH_DEFAULT_LENGTH_TAG( alg ); } /* Helper function to perform common nonce length checks. */ static psa_status_t psa_aead_check_nonce_length( psa_algorithm_t alg, size_t nonce_length ) { psa_algorithm_t base_alg = psa_aead_get_base_algorithm( alg ); switch(base_alg) { #if defined(PSA_WANT_ALG_GCM) case PSA_ALG_GCM: /* Not checking max nonce size here as GCM spec allows almost * arbitrarily large nonces. Please note that we do not generally * recommend the usage of nonces of greater length than * PSA_AEAD_NONCE_MAX_SIZE, as large nonces are hashed to a shorter * size, which can then lead to collisions if you encrypt a very * large number of messages.*/ if( nonce_length != 0 ) return( PSA_SUCCESS ); break; #endif /* PSA_WANT_ALG_GCM */ #if defined(PSA_WANT_ALG_CCM) case PSA_ALG_CCM: if( nonce_length >= 7 && nonce_length <= 13 ) return( PSA_SUCCESS ); break; #endif /* PSA_WANT_ALG_CCM */ #if defined(PSA_WANT_ALG_CHACHA20_POLY1305) case PSA_ALG_CHACHA20_POLY1305: if( nonce_length == 12 ) return( PSA_SUCCESS ); else if( nonce_length == 8 ) return( PSA_ERROR_NOT_SUPPORTED ); break; #endif /* PSA_WANT_ALG_CHACHA20_POLY1305 */ default: return( PSA_ERROR_NOT_SUPPORTED ); } return( PSA_ERROR_INVALID_ARGUMENT ); } static psa_status_t psa_aead_check_algorithm( psa_algorithm_t alg ) { if( !PSA_ALG_IS_AEAD( alg ) || PSA_ALG_IS_WILDCARD( alg ) ) return( PSA_ERROR_INVALID_ARGUMENT ); return( PSA_SUCCESS ); } psa_status_t psa_aead_encrypt( mbedtls_svc_key_id_t key, psa_algorithm_t alg, const uint8_t *nonce, size_t nonce_length, const uint8_t *additional_data, size_t additional_data_length, const uint8_t *plaintext, size_t plaintext_length, uint8_t *ciphertext, size_t ciphertext_size, size_t *ciphertext_length ) { psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED; psa_key_slot_t *slot; *ciphertext_length = 0; status = psa_aead_check_algorithm( alg ); if( status != PSA_SUCCESS ) return( status ); status = psa_get_and_lock_key_slot_with_policy( key, &slot, PSA_KEY_USAGE_ENCRYPT, alg ); if( status != PSA_SUCCESS ) return( status ); psa_key_attributes_t attributes = { .core = slot->attr }; status = psa_aead_check_nonce_length( alg, nonce_length ); if( status != PSA_SUCCESS ) goto exit; status = psa_driver_wrapper_aead_encrypt( &attributes, slot->key.data, slot->key.bytes, alg, nonce, nonce_length, additional_data, additional_data_length, plaintext, plaintext_length, ciphertext, ciphertext_size, ciphertext_length ); if( status != PSA_SUCCESS && ciphertext_size != 0 ) memset( ciphertext, 0, ciphertext_size ); exit: psa_unlock_key_slot( slot ); return( status ); } psa_status_t psa_aead_decrypt( mbedtls_svc_key_id_t key, psa_algorithm_t alg, const uint8_t *nonce, size_t nonce_length, const uint8_t *additional_data, size_t additional_data_length, const uint8_t *ciphertext, size_t ciphertext_length, uint8_t *plaintext, size_t plaintext_size, size_t *plaintext_length ) { psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED; psa_key_slot_t *slot; *plaintext_length = 0; status = psa_aead_check_algorithm( alg ); if( status != PSA_SUCCESS ) return( status ); status = psa_get_and_lock_key_slot_with_policy( key, &slot, PSA_KEY_USAGE_DECRYPT, alg ); if( status != PSA_SUCCESS ) return( status ); psa_key_attributes_t attributes = { .core = slot->attr }; status = psa_aead_check_nonce_length( alg, nonce_length ); if( status != PSA_SUCCESS ) goto exit; status = psa_driver_wrapper_aead_decrypt( &attributes, slot->key.data, slot->key.bytes, alg, nonce, nonce_length, additional_data, additional_data_length, ciphertext, ciphertext_length, plaintext, plaintext_size, plaintext_length ); if( status != PSA_SUCCESS && plaintext_size != 0 ) memset( plaintext, 0, plaintext_size ); exit: psa_unlock_key_slot( slot ); return( status ); } static psa_status_t psa_validate_tag_length( psa_aead_operation_t *operation, psa_algorithm_t alg ) { uint8_t tag_len = 0; if( psa_driver_get_tag_len( operation, &tag_len ) != PSA_SUCCESS ) { return( PSA_ERROR_INVALID_ARGUMENT ); } switch( PSA_ALG_AEAD_WITH_SHORTENED_TAG( alg, 0 ) ) { #if defined(MBEDTLS_PSA_BUILTIN_ALG_CCM) case PSA_ALG_AEAD_WITH_SHORTENED_TAG( PSA_ALG_CCM, 0 ): /* CCM allows the following tag lengths: 4, 6, 8, 10, 12, 14, 16.*/ if( tag_len < 4 || tag_len > 16 || tag_len % 2 ) return( PSA_ERROR_INVALID_ARGUMENT ); break; #endif /* MBEDTLS_PSA_BUILTIN_ALG_CCM */ #if defined(MBEDTLS_PSA_BUILTIN_ALG_GCM) case PSA_ALG_AEAD_WITH_SHORTENED_TAG( PSA_ALG_GCM, 0 ): /* GCM allows the following tag lengths: 4, 8, 12, 13, 14, 15, 16. */ if( tag_len != 4 && tag_len != 8 && ( tag_len < 12 || tag_len > 16 ) ) return( PSA_ERROR_INVALID_ARGUMENT ); break; #endif /* MBEDTLS_PSA_BUILTIN_ALG_GCM */ #if defined(MBEDTLS_PSA_BUILTIN_ALG_CHACHA20_POLY1305) case PSA_ALG_AEAD_WITH_SHORTENED_TAG( PSA_ALG_CHACHA20_POLY1305, 0 ): /* We only support the default tag length. */ if( tag_len != 16 ) return( PSA_ERROR_INVALID_ARGUMENT ); break; #endif /* MBEDTLS_PSA_BUILTIN_ALG_CHACHA20_POLY1305 */ default: (void) tag_len; return( PSA_ERROR_NOT_SUPPORTED ); } return( PSA_SUCCESS ); } /* Set the key for a multipart authenticated operation. */ static psa_status_t psa_aead_setup( psa_aead_operation_t *operation, int is_encrypt, mbedtls_svc_key_id_t key, psa_algorithm_t alg ) { psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED; psa_status_t unlock_status = PSA_ERROR_CORRUPTION_DETECTED; psa_key_slot_t *slot = NULL; psa_key_usage_t key_usage = 0; status = psa_aead_check_algorithm( alg ); if( status != PSA_SUCCESS ) goto exit; if( operation->id != 0 ) { status = PSA_ERROR_BAD_STATE; goto exit; } if( operation->nonce_set || operation->lengths_set || operation->ad_started || operation->body_started ) { status = PSA_ERROR_BAD_STATE; goto exit; } if( is_encrypt ) key_usage = PSA_KEY_USAGE_ENCRYPT; else key_usage = PSA_KEY_USAGE_DECRYPT; status = psa_get_and_lock_key_slot_with_policy( key, &slot, key_usage, alg ); if( status != PSA_SUCCESS ) goto exit; psa_key_attributes_t attributes = { .core = slot->attr }; if( is_encrypt ) status = psa_driver_wrapper_aead_encrypt_setup( operation, &attributes, slot->key.data, slot->key.bytes, alg ); else status = psa_driver_wrapper_aead_decrypt_setup( operation, &attributes, slot->key.data, slot->key.bytes, alg ); if( status != PSA_SUCCESS ) goto exit; if( ( status = psa_validate_tag_length( operation, alg ) ) != PSA_SUCCESS ) goto exit; operation->key_type = psa_get_key_type( &attributes ); exit: unlock_status = psa_unlock_key_slot( slot ); if( status == PSA_SUCCESS ) { status = unlock_status; operation->alg = psa_aead_get_base_algorithm( alg ); operation->is_encrypt = is_encrypt; } else psa_aead_abort( operation ); return( status ); } /* Set the key for a multipart authenticated encryption operation. */ psa_status_t psa_aead_encrypt_setup( psa_aead_operation_t *operation, mbedtls_svc_key_id_t key, psa_algorithm_t alg ) { return( psa_aead_setup( operation, 1, key, alg ) ); } /* Set the key for a multipart authenticated decryption operation. */ psa_status_t psa_aead_decrypt_setup( psa_aead_operation_t *operation, mbedtls_svc_key_id_t key, psa_algorithm_t alg ) { return( psa_aead_setup( operation, 0, key, alg ) ); } /* Generate a random nonce / IV for multipart AEAD operation */ psa_status_t psa_aead_generate_nonce( psa_aead_operation_t *operation, uint8_t *nonce, size_t nonce_size, size_t *nonce_length ) { psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED; uint8_t local_nonce[PSA_AEAD_NONCE_MAX_SIZE]; size_t required_nonce_size; *nonce_length = 0; if( operation->id == 0 ) { status = PSA_ERROR_BAD_STATE; goto exit; } if( operation->nonce_set || !operation->is_encrypt ) { status = PSA_ERROR_BAD_STATE; goto exit; } /* For CCM, this size may not be correct according to the PSA * specification. The PSA Crypto 1.0.1 specification states: * * CCM encodes the plaintext length pLen in L octets, with L the smallest * integer >= 2 where pLen < 2^(8L). The nonce length is then 15 - L bytes. * * However this restriction that L has to be the smallest integer is not * applied in practice, and it is not implementable here since the * plaintext length may or may not be known at this time. */ required_nonce_size = PSA_AEAD_NONCE_LENGTH( operation->key_type, operation->alg ); if( nonce_size < required_nonce_size ) { status = PSA_ERROR_BUFFER_TOO_SMALL; goto exit; } status = psa_generate_random( local_nonce, required_nonce_size ); if( status != PSA_SUCCESS ) goto exit; status = psa_aead_set_nonce( operation, local_nonce, required_nonce_size ); exit: if( status == PSA_SUCCESS ) { memcpy( nonce, local_nonce, required_nonce_size ); *nonce_length = required_nonce_size; } else psa_aead_abort( operation ); return( status ); } /* Set the nonce for a multipart authenticated encryption or decryption operation.*/ psa_status_t psa_aead_set_nonce( psa_aead_operation_t *operation, const uint8_t *nonce, size_t nonce_length ) { psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED; if( operation->id == 0 ) { status = PSA_ERROR_BAD_STATE; goto exit; } if( operation->nonce_set ) { status = PSA_ERROR_BAD_STATE; goto exit; } status = psa_aead_check_nonce_length( operation->alg, nonce_length ); if( status != PSA_SUCCESS ) { status = PSA_ERROR_INVALID_ARGUMENT; goto exit; } status = psa_driver_wrapper_aead_set_nonce( operation, nonce, nonce_length ); exit: if( status == PSA_SUCCESS ) operation->nonce_set = 1; else psa_aead_abort( operation ); return( status ); } /* Declare the lengths of the message and additional data for multipart AEAD. */ psa_status_t psa_aead_set_lengths( psa_aead_operation_t *operation, size_t ad_length, size_t plaintext_length ) { psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED; if( operation->id == 0 ) { status = PSA_ERROR_BAD_STATE; goto exit; } if( operation->lengths_set || operation->ad_started || operation->body_started ) { status = PSA_ERROR_BAD_STATE; goto exit; } switch(operation->alg) { #if defined(PSA_WANT_ALG_GCM) case PSA_ALG_GCM: /* Lengths can only be too large for GCM if size_t is bigger than 32 * bits. Without the guard this code will generate warnings on 32bit * builds. */ #if SIZE_MAX > UINT32_MAX if( (( uint64_t ) ad_length ) >> 61 != 0 || (( uint64_t ) plaintext_length ) > 0xFFFFFFFE0ull ) { status = PSA_ERROR_INVALID_ARGUMENT; goto exit; } #endif break; #endif /* PSA_WANT_ALG_GCM */ #if defined(PSA_WANT_ALG_CCM) case PSA_ALG_CCM: if( ad_length > 0xFF00 ) { status = PSA_ERROR_INVALID_ARGUMENT; goto exit; } break; #endif /* PSA_WANT_ALG_CCM */ #if defined(PSA_WANT_ALG_CHACHA20_POLY1305) case PSA_ALG_CHACHA20_POLY1305: /* No length restrictions for ChaChaPoly. */ break; #endif /* PSA_WANT_ALG_CHACHA20_POLY1305 */ default: break; } status = psa_driver_wrapper_aead_set_lengths( operation, ad_length, plaintext_length ); exit: if( status == PSA_SUCCESS ) { operation->ad_remaining = ad_length; operation->body_remaining = plaintext_length; operation->lengths_set = 1; } else psa_aead_abort( operation ); return( status ); } /* Pass additional data to an active multipart AEAD operation. */ psa_status_t psa_aead_update_ad( psa_aead_operation_t *operation, const uint8_t *input, size_t input_length ) { psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED; if( operation->id == 0 ) { status = PSA_ERROR_BAD_STATE; goto exit; } if( !operation->nonce_set || operation->body_started ) { status = PSA_ERROR_BAD_STATE; goto exit; } if( operation->lengths_set ) { if( operation->ad_remaining < input_length ) { status = PSA_ERROR_INVALID_ARGUMENT; goto exit; } operation->ad_remaining -= input_length; } #if defined(PSA_WANT_ALG_CCM) else if( operation->alg == PSA_ALG_CCM ) { status = PSA_ERROR_BAD_STATE; goto exit; } #endif /* PSA_WANT_ALG_CCM */ status = psa_driver_wrapper_aead_update_ad( operation, input, input_length ); exit: if( status == PSA_SUCCESS ) operation->ad_started = 1; else psa_aead_abort( operation ); return( status ); } /* Encrypt or decrypt a message fragment in an active multipart AEAD operation.*/ psa_status_t psa_aead_update( psa_aead_operation_t *operation, const uint8_t *input, size_t input_length, uint8_t *output, size_t output_size, size_t *output_length ) { psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED; *output_length = 0; if( operation->id == 0 ) { status = PSA_ERROR_BAD_STATE; goto exit; } if( !operation->nonce_set ) { status = PSA_ERROR_BAD_STATE; goto exit; } if( operation->lengths_set ) { /* Additional data length was supplied, but not all the additional data was supplied.*/ if( operation->ad_remaining != 0 ) { status = PSA_ERROR_INVALID_ARGUMENT; goto exit; } /* Too much data provided. */ if( operation->body_remaining < input_length ) { status = PSA_ERROR_INVALID_ARGUMENT; goto exit; } operation->body_remaining -= input_length; } #if defined(PSA_WANT_ALG_CCM) else if( operation->alg == PSA_ALG_CCM ) { status = PSA_ERROR_BAD_STATE; goto exit; } #endif /* PSA_WANT_ALG_CCM */ status = psa_driver_wrapper_aead_update( operation, input, input_length, output, output_size, output_length ); exit: if( status == PSA_SUCCESS ) operation->body_started = 1; else psa_aead_abort( operation ); return( status ); } static psa_status_t psa_aead_final_checks( const psa_aead_operation_t *operation ) { if( operation->id == 0 || !operation->nonce_set ) return( PSA_ERROR_BAD_STATE ); if( operation->lengths_set && ( operation->ad_remaining != 0 || operation->body_remaining != 0 ) ) return( PSA_ERROR_INVALID_ARGUMENT ); return( PSA_SUCCESS ); } /* Finish encrypting a message in a multipart AEAD operation. */ psa_status_t psa_aead_finish( psa_aead_operation_t *operation, uint8_t *ciphertext, size_t ciphertext_size, size_t *ciphertext_length, uint8_t *tag, size_t tag_size, size_t *tag_length ) { psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED; *ciphertext_length = 0; *tag_length = tag_size; status = psa_aead_final_checks( operation ); if( status != PSA_SUCCESS ) goto exit; if( !operation->is_encrypt ) { status = PSA_ERROR_BAD_STATE; goto exit; } status = psa_driver_wrapper_aead_finish( operation, ciphertext, ciphertext_size, ciphertext_length, tag, tag_size, tag_length ); exit: /* In case the operation fails and the user fails to check for failure or * the zero tag size, make sure the tag is set to something implausible. * Even if the operation succeeds, make sure we clear the rest of the * buffer to prevent potential leakage of anything previously placed in * the same buffer.*/ if( tag != NULL ) { if( status != PSA_SUCCESS ) memset( tag, '!', tag_size ); else if( *tag_length < tag_size ) memset( tag + *tag_length, '!', ( tag_size - *tag_length ) ); } psa_aead_abort( operation ); return( status ); } /* Finish authenticating and decrypting a message in a multipart AEAD operation.*/ psa_status_t psa_aead_verify( psa_aead_operation_t *operation, uint8_t *plaintext, size_t plaintext_size, size_t *plaintext_length, const uint8_t *tag, size_t tag_length ) { psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED; *plaintext_length = 0; status = psa_aead_final_checks( operation ); if( status != PSA_SUCCESS ) goto exit; if( operation->is_encrypt ) { status = PSA_ERROR_BAD_STATE; goto exit; } status = psa_driver_wrapper_aead_verify( operation, plaintext, plaintext_size, plaintext_length, tag, tag_length ); exit: psa_aead_abort( operation ); return( status ); } /* Abort an AEAD operation. */ psa_status_t psa_aead_abort( psa_aead_operation_t *operation ) { psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED; if( operation->id == 0 ) { /* The object has (apparently) been initialized but it is not (yet) * in use. It's ok to call abort on such an object, and there's * nothing to do. */ return( PSA_SUCCESS ); } status = psa_driver_wrapper_aead_abort( operation ); memset( operation, 0, sizeof( *operation ) ); return( status ); } /****************************************************************/ /* Generators */ /****************************************************************/ #if defined(BUILTIN_ALG_ANY_HKDF) || \ defined(MBEDTLS_PSA_BUILTIN_ALG_TLS12_PRF) || \ defined(MBEDTLS_PSA_BUILTIN_ALG_TLS12_PSK_TO_MS) #define AT_LEAST_ONE_BUILTIN_KDF #endif /* At least one builtin KDF */ #if defined(BUILTIN_ALG_ANY_HKDF) || \ defined(MBEDTLS_PSA_BUILTIN_ALG_TLS12_PRF) || \ defined(MBEDTLS_PSA_BUILTIN_ALG_TLS12_PSK_TO_MS) static psa_status_t psa_key_derivation_start_hmac( psa_mac_operation_t *operation, psa_algorithm_t hash_alg, const uint8_t *hmac_key, size_t hmac_key_length ) { psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED; psa_key_attributes_t attributes = PSA_KEY_ATTRIBUTES_INIT; psa_set_key_type( &attributes, PSA_KEY_TYPE_HMAC ); psa_set_key_bits( &attributes, PSA_BYTES_TO_BITS( hmac_key_length ) ); psa_set_key_usage_flags( &attributes, PSA_KEY_USAGE_SIGN_HASH ); operation->is_sign = 1; operation->mac_size = PSA_HASH_LENGTH( hash_alg ); status = psa_driver_wrapper_mac_sign_setup( operation, &attributes, hmac_key, hmac_key_length, PSA_ALG_HMAC( hash_alg ) ); psa_reset_key_attributes( &attributes ); return( status ); } #endif /* KDF algorithms reliant on HMAC */ #define HKDF_STATE_INIT 0 /* no input yet */ #define HKDF_STATE_STARTED 1 /* got salt */ #define HKDF_STATE_KEYED 2 /* got key */ #define HKDF_STATE_OUTPUT 3 /* output started */ static psa_algorithm_t psa_key_derivation_get_kdf_alg( const psa_key_derivation_operation_t *operation ) { if ( PSA_ALG_IS_KEY_AGREEMENT( operation->alg ) ) return( PSA_ALG_KEY_AGREEMENT_GET_KDF( operation->alg ) ); else return( operation->alg ); } psa_status_t psa_key_derivation_abort( psa_key_derivation_operation_t *operation ) { psa_status_t status = PSA_SUCCESS; psa_algorithm_t kdf_alg = psa_key_derivation_get_kdf_alg( operation ); if( kdf_alg == 0 ) { /* The object has (apparently) been initialized but it is not * in use. It's ok to call abort on such an object, and there's * nothing to do. */ } else #if defined(BUILTIN_ALG_ANY_HKDF) if( PSA_ALG_IS_ANY_HKDF( kdf_alg ) ) { mbedtls_free( operation->ctx.hkdf.info ); status = psa_mac_abort( &operation->ctx.hkdf.hmac ); } else #endif /* BUILTIN_ALG_ANY_HKDF */ #if defined(MBEDTLS_PSA_BUILTIN_ALG_TLS12_PRF) || \ defined(MBEDTLS_PSA_BUILTIN_ALG_TLS12_PSK_TO_MS) if( PSA_ALG_IS_TLS12_PRF( kdf_alg ) || /* TLS-1.2 PSK-to-MS KDF uses the same core as TLS-1.2 PRF */ PSA_ALG_IS_TLS12_PSK_TO_MS( kdf_alg ) ) { if( operation->ctx.tls12_prf.secret != NULL ) { mbedtls_platform_zeroize( operation->ctx.tls12_prf.secret, operation->ctx.tls12_prf.secret_length ); mbedtls_free( operation->ctx.tls12_prf.secret ); } if( operation->ctx.tls12_prf.seed != NULL ) { mbedtls_platform_zeroize( operation->ctx.tls12_prf.seed, operation->ctx.tls12_prf.seed_length ); mbedtls_free( operation->ctx.tls12_prf.seed ); } if( operation->ctx.tls12_prf.label != NULL ) { mbedtls_platform_zeroize( operation->ctx.tls12_prf.label, operation->ctx.tls12_prf.label_length ); mbedtls_free( operation->ctx.tls12_prf.label ); } if( operation->ctx.tls12_prf.other_secret != NULL ) { mbedtls_platform_zeroize( operation->ctx.tls12_prf.other_secret, operation->ctx.tls12_prf.other_secret_length ); mbedtls_free( operation->ctx.tls12_prf.other_secret ); } status = PSA_SUCCESS; /* We leave the fields Ai and output_block to be erased safely by the * mbedtls_platform_zeroize() in the end of this function. */ } else #endif /* defined(MBEDTLS_PSA_BUILTIN_ALG_TLS12_PRF) || * defined(MBEDTLS_PSA_BUILTIN_ALG_TLS12_PSK_TO_MS) */ { status = PSA_ERROR_BAD_STATE; } mbedtls_platform_zeroize( operation, sizeof( *operation ) ); return( status ); } psa_status_t psa_key_derivation_get_capacity(const psa_key_derivation_operation_t *operation, size_t *capacity) { if( operation->alg == 0 ) { /* This is a blank key derivation operation. */ return( PSA_ERROR_BAD_STATE ); } *capacity = operation->capacity; return( PSA_SUCCESS ); } psa_status_t psa_key_derivation_set_capacity( psa_key_derivation_operation_t *operation, size_t capacity ) { if( operation->alg == 0 ) return( PSA_ERROR_BAD_STATE ); if( capacity > operation->capacity ) return( PSA_ERROR_INVALID_ARGUMENT ); operation->capacity = capacity; return( PSA_SUCCESS ); } #if defined(BUILTIN_ALG_ANY_HKDF) /* Read some bytes from an HKDF-based operation. */ static psa_status_t psa_key_derivation_hkdf_read( psa_hkdf_key_derivation_t *hkdf, psa_algorithm_t kdf_alg, uint8_t *output, size_t output_length ) { psa_algorithm_t hash_alg = PSA_ALG_HKDF_GET_HASH( kdf_alg ); uint8_t hash_length = PSA_HASH_LENGTH( hash_alg ); size_t hmac_output_length; psa_status_t status; #if defined(MBEDTLS_PSA_BUILTIN_ALG_HKDF_EXTRACT) const uint8_t last_block = PSA_ALG_IS_HKDF_EXTRACT( kdf_alg ) ? 0 : 0xff; #else const uint8_t last_block = 0xff; #endif /* MBEDTLS_PSA_BUILTIN_ALG_HKDF_EXTRACT */ if( hkdf->state < HKDF_STATE_KEYED || ( !hkdf->info_set #if defined(MBEDTLS_PSA_BUILTIN_ALG_HKDF_EXTRACT) && !PSA_ALG_IS_HKDF_EXTRACT( kdf_alg ) #endif /* MBEDTLS_PSA_BUILTIN_ALG_HKDF_EXTRACT */ ) ) return( PSA_ERROR_BAD_STATE ); hkdf->state = HKDF_STATE_OUTPUT; while( output_length != 0 ) { /* Copy what remains of the current block */ uint8_t n = hash_length - hkdf->offset_in_block; if( n > output_length ) n = (uint8_t) output_length; memcpy( output, hkdf->output_block + hkdf->offset_in_block, n ); output += n; output_length -= n; hkdf->offset_in_block += n; if( output_length == 0 ) break; /* We can't be wanting more output after the last block, otherwise * the capacity check in psa_key_derivation_output_bytes() would have * prevented this call. It could happen only if the operation * object was corrupted or if this function is called directly * inside the library. */ if( hkdf->block_number == last_block ) return( PSA_ERROR_BAD_STATE ); /* We need a new block */ ++hkdf->block_number; hkdf->offset_in_block = 0; status = psa_key_derivation_start_hmac( &hkdf->hmac, hash_alg, hkdf->prk, hash_length ); if( status != PSA_SUCCESS ) return( status ); if( hkdf->block_number != 1 ) { status = psa_mac_update( &hkdf->hmac, hkdf->output_block, hash_length ); if( status != PSA_SUCCESS ) return( status ); } status = psa_mac_update( &hkdf->hmac, hkdf->info, hkdf->info_length ); if( status != PSA_SUCCESS ) return( status ); status = psa_mac_update( &hkdf->hmac, &hkdf->block_number, 1 ); if( status != PSA_SUCCESS ) return( status ); status = psa_mac_sign_finish( &hkdf->hmac, hkdf->output_block, sizeof( hkdf->output_block ), &hmac_output_length ); if( status != PSA_SUCCESS ) return( status ); } return( PSA_SUCCESS ); } #endif /* BUILTIN_ALG_ANY_HKDF */ #if defined(MBEDTLS_PSA_BUILTIN_ALG_TLS12_PRF) || \ defined(MBEDTLS_PSA_BUILTIN_ALG_TLS12_PSK_TO_MS) static psa_status_t psa_key_derivation_tls12_prf_generate_next_block( psa_tls12_prf_key_derivation_t *tls12_prf, psa_algorithm_t alg ) { psa_algorithm_t hash_alg = PSA_ALG_HKDF_GET_HASH( alg ); uint8_t hash_length = PSA_HASH_LENGTH( hash_alg ); psa_mac_operation_t hmac = PSA_MAC_OPERATION_INIT; size_t hmac_output_length; psa_status_t status, cleanup_status; /* We can't be wanting more output after block 0xff, otherwise * the capacity check in psa_key_derivation_output_bytes() would have * prevented this call. It could happen only if the operation * object was corrupted or if this function is called directly * inside the library. */ if( tls12_prf->block_number == 0xff ) return( PSA_ERROR_CORRUPTION_DETECTED ); /* We need a new block */ ++tls12_prf->block_number; tls12_prf->left_in_block = hash_length; /* Recall the definition of the TLS-1.2-PRF from RFC 5246: * * PRF(secret, label, seed) = P_(secret, label + seed) * * P_hash(secret, seed) = HMAC_hash(secret, A(1) + seed) + * HMAC_hash(secret, A(2) + seed) + * HMAC_hash(secret, A(3) + seed) + ... * * A(0) = seed * A(i) = HMAC_hash(secret, A(i-1)) * * The `psa_tls12_prf_key_derivation` structure saves the block * `HMAC_hash(secret, A(i) + seed)` from which the output * is currently extracted as `output_block` and where i is * `block_number`. */ status = psa_key_derivation_start_hmac( &hmac, hash_alg, tls12_prf->secret, tls12_prf->secret_length ); if( status != PSA_SUCCESS ) goto cleanup; /* Calculate A(i) where i = tls12_prf->block_number. */ if( tls12_prf->block_number == 1 ) { /* A(1) = HMAC_hash(secret, A(0)), where A(0) = seed. (The RFC overloads * the variable seed and in this instance means it in the context of the * P_hash function, where seed = label + seed.) */ status = psa_mac_update( &hmac, tls12_prf->label, tls12_prf->label_length ); if( status != PSA_SUCCESS ) goto cleanup; status = psa_mac_update( &hmac, tls12_prf->seed, tls12_prf->seed_length ); if( status != PSA_SUCCESS ) goto cleanup; } else { /* A(i) = HMAC_hash(secret, A(i-1)) */ status = psa_mac_update( &hmac, tls12_prf->Ai, hash_length ); if( status != PSA_SUCCESS ) goto cleanup; } status = psa_mac_sign_finish( &hmac, tls12_prf->Ai, hash_length, &hmac_output_length ); if( hmac_output_length != hash_length ) status = PSA_ERROR_CORRUPTION_DETECTED; if( status != PSA_SUCCESS ) goto cleanup; /* Calculate HMAC_hash(secret, A(i) + label + seed). */ status = psa_key_derivation_start_hmac( &hmac, hash_alg, tls12_prf->secret, tls12_prf->secret_length ); if( status != PSA_SUCCESS ) goto cleanup; status = psa_mac_update( &hmac, tls12_prf->Ai, hash_length ); if( status != PSA_SUCCESS ) goto cleanup; status = psa_mac_update( &hmac, tls12_prf->label, tls12_prf->label_length ); if( status != PSA_SUCCESS ) goto cleanup; status = psa_mac_update( &hmac, tls12_prf->seed, tls12_prf->seed_length ); if( status != PSA_SUCCESS ) goto cleanup; status = psa_mac_sign_finish( &hmac, tls12_prf->output_block, hash_length, &hmac_output_length ); if( status != PSA_SUCCESS ) goto cleanup; cleanup: cleanup_status = psa_mac_abort( &hmac ); if( status == PSA_SUCCESS && cleanup_status != PSA_SUCCESS ) status = cleanup_status; return( status ); } static psa_status_t psa_key_derivation_tls12_prf_read( psa_tls12_prf_key_derivation_t *tls12_prf, psa_algorithm_t alg, uint8_t *output, size_t output_length ) { psa_algorithm_t hash_alg = PSA_ALG_TLS12_PRF_GET_HASH( alg ); uint8_t hash_length = PSA_HASH_LENGTH( hash_alg ); psa_status_t status; uint8_t offset, length; switch( tls12_prf->state ) { case PSA_TLS12_PRF_STATE_LABEL_SET: tls12_prf->state = PSA_TLS12_PRF_STATE_OUTPUT; break; case PSA_TLS12_PRF_STATE_OUTPUT: break; default: return( PSA_ERROR_BAD_STATE ); } while( output_length != 0 ) { /* Check if we have fully processed the current block. */ if( tls12_prf->left_in_block == 0 ) { status = psa_key_derivation_tls12_prf_generate_next_block( tls12_prf, alg ); if( status != PSA_SUCCESS ) return( status ); continue; } if( tls12_prf->left_in_block > output_length ) length = (uint8_t) output_length; else length = tls12_prf->left_in_block; offset = hash_length - tls12_prf->left_in_block; memcpy( output, tls12_prf->output_block + offset, length ); output += length; output_length -= length; tls12_prf->left_in_block -= length; } return( PSA_SUCCESS ); } #endif /* MBEDTLS_PSA_BUILTIN_ALG_TLS12_PRF || * MBEDTLS_PSA_BUILTIN_ALG_TLS12_PSK_TO_MS */ psa_status_t psa_key_derivation_output_bytes( psa_key_derivation_operation_t *operation, uint8_t *output, size_t output_length ) { psa_status_t status; psa_algorithm_t kdf_alg = psa_key_derivation_get_kdf_alg( operation ); if( operation->alg == 0 ) { /* This is a blank operation. */ return( PSA_ERROR_BAD_STATE ); } if( output_length > operation->capacity ) { operation->capacity = 0; /* Go through the error path to wipe all confidential data now * that the operation object is useless. */ status = PSA_ERROR_INSUFFICIENT_DATA; goto exit; } if( output_length == 0 && operation->capacity == 0 ) { /* Edge case: this is a finished operation, and 0 bytes * were requested. The right error in this case could * be either INSUFFICIENT_CAPACITY or BAD_STATE. Return * INSUFFICIENT_CAPACITY, which is right for a finished * operation, for consistency with the case when * output_length > 0. */ return( PSA_ERROR_INSUFFICIENT_DATA ); } operation->capacity -= output_length; #if defined(BUILTIN_ALG_ANY_HKDF) if( PSA_ALG_IS_ANY_HKDF( kdf_alg ) ) { status = psa_key_derivation_hkdf_read( &operation->ctx.hkdf, kdf_alg, output, output_length ); } else #endif /* BUILTIN_ALG_ANY_HKDF */ #if defined(MBEDTLS_PSA_BUILTIN_ALG_TLS12_PRF) || \ defined(MBEDTLS_PSA_BUILTIN_ALG_TLS12_PSK_TO_MS) if( PSA_ALG_IS_TLS12_PRF( kdf_alg ) || PSA_ALG_IS_TLS12_PSK_TO_MS( kdf_alg ) ) { status = psa_key_derivation_tls12_prf_read( &operation->ctx.tls12_prf, kdf_alg, output, output_length ); } else #endif /* MBEDTLS_PSA_BUILTIN_ALG_TLS12_PRF || * MBEDTLS_PSA_BUILTIN_ALG_TLS12_PSK_TO_MS */ { (void) kdf_alg; return( PSA_ERROR_BAD_STATE ); } exit: if( status != PSA_SUCCESS ) { /* Preserve the algorithm upon errors, but clear all sensitive state. * This allows us to differentiate between exhausted operations and * blank operations, so we can return PSA_ERROR_BAD_STATE on blank * operations. */ psa_algorithm_t alg = operation->alg; psa_key_derivation_abort( operation ); operation->alg = alg; memset( output, '!', output_length ); } return( status ); } #if defined(MBEDTLS_PSA_BUILTIN_KEY_TYPE_DES) static void psa_des_set_key_parity( uint8_t *data, size_t data_size ) { if( data_size >= 8 ) mbedtls_des_key_set_parity( data ); if( data_size >= 16 ) mbedtls_des_key_set_parity( data + 8 ); if( data_size >= 24 ) mbedtls_des_key_set_parity( data + 16 ); } #endif /* MBEDTLS_PSA_BUILTIN_KEY_TYPE_DES */ /* * ECC keys on a Weierstrass elliptic curve require the generation * of a private key which is an integer * in the range [1, N - 1], where N is the boundary of the private key domain: * N is the prime p for Diffie-Hellman, or the order of the * curve’s base point for ECC. * * Let m be the bit size of N, such that 2^m > N >= 2^(m-1). * This function generates the private key using the following process: * * 1. Draw a byte string of length ceiling(m/8) bytes. * 2. If m is not a multiple of 8, set the most significant * (8 * ceiling(m/8) - m) bits of the first byte in the string to zero. * 3. Convert the string to integer k by decoding it as a big-endian byte string. * 4. If k > N - 2, discard the result and return to step 1. * 5. Output k + 1 as the private key. * * This method allows compliance to NIST standards, specifically the methods titled * Key-Pair Generation by Testing Candidates in the following publications: * - NIST Special Publication 800-56A: Recommendation for Pair-Wise Key-Establishment * Schemes Using Discrete Logarithm Cryptography [SP800-56A] §5.6.1.1.4 for * Diffie-Hellman keys. * * - [SP800-56A] §5.6.1.2.2 or FIPS Publication 186-4: Digital Signature * Standard (DSS) [FIPS186-4] §B.4.2 for elliptic curve keys. * * Note: Function allocates memory for *data buffer, so given *data should be * always NULL. */ #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) static psa_status_t psa_generate_derived_ecc_key_weierstrass_helper( psa_key_slot_t *slot, size_t bits, psa_key_derivation_operation_t *operation, uint8_t **data ) { unsigned key_out_of_range = 1; mbedtls_mpi k; mbedtls_mpi diff_N_2; int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED; mbedtls_mpi_init( &k ); mbedtls_mpi_init( &diff_N_2 ); psa_ecc_family_t curve = PSA_KEY_TYPE_ECC_GET_FAMILY( slot->attr.type ); mbedtls_ecp_group_id grp_id = mbedtls_ecc_group_of_psa( curve, bits, 0 ); if( grp_id == MBEDTLS_ECP_DP_NONE ) { ret = MBEDTLS_ERR_ASN1_INVALID_DATA; goto cleanup; } mbedtls_ecp_group ecp_group; mbedtls_ecp_group_init( &ecp_group ); MBEDTLS_MPI_CHK( mbedtls_ecp_group_load( &ecp_group, grp_id ) ); /* N is the boundary of the private key domain (ecp_group.N). */ /* Let m be the bit size of N. */ size_t m = ecp_group.nbits; size_t m_bytes = PSA_BITS_TO_BYTES( m ); /* Calculate N - 2 - it will be needed later. */ MBEDTLS_MPI_CHK( mbedtls_mpi_sub_int( &diff_N_2, &ecp_group.N, 2 ) ); /* Note: This function is always called with *data == NULL and it * allocates memory for the data buffer. */ *data = mbedtls_calloc( 1, m_bytes ); if( *data == NULL ) { ret = MBEDTLS_ERR_ASN1_ALLOC_FAILED; goto cleanup; } while( key_out_of_range ) { /* 1. Draw a byte string of length ceiling(m/8) bytes. */ if( ( status = psa_key_derivation_output_bytes( operation, *data, m_bytes ) ) != 0 ) goto cleanup; /* 2. If m is not a multiple of 8 */ if( m % 8 != 0 ) { /* Set the most significant * (8 * ceiling(m/8) - m) bits of the first byte in * the string to zero. */ uint8_t clear_bit_mask = ( 1 << ( m % 8 ) ) - 1; (*data)[0] &= clear_bit_mask; } /* 3. Convert the string to integer k by decoding it as a * big-endian byte string. */ MBEDTLS_MPI_CHK( mbedtls_mpi_read_binary( &k, *data, m_bytes ) ); /* 4. If k > N - 2, discard the result and return to step 1. * Result of comparison is returned. When it indicates error * then this function is called again. */ MBEDTLS_MPI_CHK( mbedtls_mpi_lt_mpi_ct( &diff_N_2, &k, &key_out_of_range ) ); } /* 5. Output k + 1 as the private key. */ MBEDTLS_MPI_CHK( mbedtls_mpi_add_int( &k, &k, 1 ) ); MBEDTLS_MPI_CHK( mbedtls_mpi_write_binary( &k, *data, m_bytes ) ); cleanup: if( ret != 0 ) status = mbedtls_to_psa_error( ret ); if( status != PSA_SUCCESS ) { mbedtls_free( *data ); *data = NULL; } mbedtls_mpi_free( &k ); mbedtls_mpi_free( &diff_N_2 ); return( status ); } /* ECC keys on a Montgomery elliptic curve draws a byte string whose length * is determined by the curve, and sets the mandatory bits accordingly. That is: * * - Curve25519 (PSA_ECC_FAMILY_MONTGOMERY, 255 bits): * draw a 32-byte string and process it as specified in * Elliptic Curves for Security [RFC7748] §5. * * - Curve448 (PSA_ECC_FAMILY_MONTGOMERY, 448 bits): * draw a 56-byte string and process it as specified in [RFC7748] §5. * * Note: Function allocates memory for *data buffer, so given *data should be * always NULL. */ static psa_status_t psa_generate_derived_ecc_key_montgomery_helper( size_t bits, psa_key_derivation_operation_t *operation, uint8_t **data ) { size_t output_length; psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED; switch( bits ) { case 255: output_length = 32; break; case 448: output_length = 56; break; default: return( PSA_ERROR_INVALID_ARGUMENT ); break; } *data = mbedtls_calloc( 1, output_length ); if( *data == NULL ) return( PSA_ERROR_INSUFFICIENT_MEMORY ); status = psa_key_derivation_output_bytes( operation, *data, output_length ); if( status != PSA_SUCCESS ) return status; switch( bits ) { case 255: (*data)[0] &= 248; (*data)[31] &= 127; (*data)[31] |= 64; break; case 448: (*data)[0] &= 252; (*data)[55] |= 128; break; default: return( PSA_ERROR_CORRUPTION_DETECTED ); break; } 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) */ static psa_status_t psa_generate_derived_key_internal( psa_key_slot_t *slot, size_t bits, psa_key_derivation_operation_t *operation ) { uint8_t *data = NULL; size_t bytes = PSA_BITS_TO_BYTES( bits ); size_t storage_size = bytes; psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED; if( PSA_KEY_TYPE_IS_PUBLIC_KEY( slot->attr.type ) ) return( PSA_ERROR_INVALID_ARGUMENT ); #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) if( PSA_KEY_TYPE_IS_ECC( slot->attr.type ) ) { psa_ecc_family_t curve = PSA_KEY_TYPE_ECC_GET_FAMILY( slot->attr.type ); if( PSA_ECC_FAMILY_IS_WEIERSTRASS( curve ) ) { /* Weierstrass elliptic curve */ status = psa_generate_derived_ecc_key_weierstrass_helper( slot, bits, operation, &data ); if( status != PSA_SUCCESS ) goto exit; } else { /* Montgomery elliptic curve */ status = psa_generate_derived_ecc_key_montgomery_helper( bits, operation, &data ); if( status != PSA_SUCCESS ) goto exit; } } else #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( key_type_is_raw_bytes( slot->attr.type ) ) { if( bits % 8 != 0 ) return( PSA_ERROR_INVALID_ARGUMENT ); data = mbedtls_calloc( 1, bytes ); if( data == NULL ) return( PSA_ERROR_INSUFFICIENT_MEMORY ); status = psa_key_derivation_output_bytes( operation, data, bytes ); if( status != PSA_SUCCESS ) goto exit; #if defined(MBEDTLS_PSA_BUILTIN_KEY_TYPE_DES) if( slot->attr.type == PSA_KEY_TYPE_DES ) psa_des_set_key_parity( data, bytes ); #endif /* defined(MBEDTLS_PSA_BUILTIN_KEY_TYPE_DES) */ } else return( PSA_ERROR_NOT_SUPPORTED ); slot->attr.bits = (psa_key_bits_t) bits; psa_key_attributes_t attributes = { .core = slot->attr }; if( psa_key_lifetime_is_external( attributes.core.lifetime ) ) { status = psa_driver_wrapper_get_key_buffer_size( &attributes, &storage_size ); if( status != PSA_SUCCESS ) goto exit; } status = psa_allocate_buffer_to_slot( slot, storage_size ); if( status != PSA_SUCCESS ) goto exit; status = psa_driver_wrapper_import_key( &attributes, data, bytes, slot->key.data, slot->key.bytes, &slot->key.bytes, &bits ); if( bits != slot->attr.bits ) status = PSA_ERROR_INVALID_ARGUMENT; exit: mbedtls_free( data ); return( status ); } psa_status_t psa_key_derivation_output_key( const psa_key_attributes_t *attributes, psa_key_derivation_operation_t *operation, mbedtls_svc_key_id_t *key ) { psa_status_t status; psa_key_slot_t *slot = NULL; psa_se_drv_table_entry_t *driver = NULL; *key = MBEDTLS_SVC_KEY_ID_INIT; /* Reject any attempt to create a zero-length key so that we don't * risk tripping up later, e.g. on a malloc(0) that returns NULL. */ if( psa_get_key_bits( attributes ) == 0 ) return( PSA_ERROR_INVALID_ARGUMENT ); if( operation->alg == PSA_ALG_NONE ) return( PSA_ERROR_BAD_STATE ); if( ! operation->can_output_key ) return( PSA_ERROR_NOT_PERMITTED ); status = psa_start_key_creation( PSA_KEY_CREATION_DERIVE, attributes, &slot, &driver ); #if defined(MBEDTLS_PSA_CRYPTO_SE_C) if( driver != NULL ) { /* Deriving a key in a secure element is not implemented yet. */ status = PSA_ERROR_NOT_SUPPORTED; } #endif /* MBEDTLS_PSA_CRYPTO_SE_C */ if( status == PSA_SUCCESS ) { status = psa_generate_derived_key_internal( slot, attributes->core.bits, operation ); } if( status == PSA_SUCCESS ) status = psa_finish_key_creation( slot, driver, key ); if( status != PSA_SUCCESS ) psa_fail_key_creation( slot, driver ); return( status ); } /****************************************************************/ /* Key derivation */ /****************************************************************/ #if defined(AT_LEAST_ONE_BUILTIN_KDF) static int is_kdf_alg_supported( psa_algorithm_t kdf_alg ) { #if defined(MBEDTLS_PSA_BUILTIN_ALG_HKDF) if( PSA_ALG_IS_HKDF( kdf_alg ) ) return( 1 ); #endif #if defined(MBEDTLS_PSA_BUILTIN_ALG_HKDF_EXTRACT) if( PSA_ALG_IS_HKDF_EXTRACT( kdf_alg ) ) return( 1 ); #endif #if defined(MBEDTLS_PSA_BUILTIN_ALG_HKDF_EXPAND) if( PSA_ALG_IS_HKDF_EXPAND( kdf_alg ) ) return( 1 ); #endif #if defined(MBEDTLS_PSA_BUILTIN_ALG_TLS12_PRF) if( PSA_ALG_IS_TLS12_PRF( kdf_alg ) ) return( 1 ); #endif #if defined(MBEDTLS_PSA_BUILTIN_ALG_TLS12_PSK_TO_MS) if( PSA_ALG_IS_TLS12_PSK_TO_MS( kdf_alg ) ) return( 1 ); #endif return( 0 ); } static psa_status_t psa_hash_try_support( psa_algorithm_t alg ) { psa_hash_operation_t operation = PSA_HASH_OPERATION_INIT; psa_status_t status = psa_hash_setup( &operation, alg ); psa_hash_abort( &operation ); return( status ); } static psa_status_t psa_key_derivation_setup_kdf( psa_key_derivation_operation_t *operation, psa_algorithm_t kdf_alg ) { /* Make sure that operation->ctx is properly zero-initialised. (Macro * initialisers for this union leave some bytes unspecified.) */ memset( &operation->ctx, 0, sizeof( operation->ctx ) ); /* Make sure that kdf_alg is a supported key derivation algorithm. */ if( ! is_kdf_alg_supported( kdf_alg ) ) return( PSA_ERROR_NOT_SUPPORTED ); /* All currently supported key derivation algorithms are based on a * hash algorithm. */ psa_algorithm_t hash_alg = PSA_ALG_HKDF_GET_HASH( kdf_alg ); size_t hash_size = PSA_HASH_LENGTH( hash_alg ); if( hash_size == 0 ) return( PSA_ERROR_NOT_SUPPORTED ); /* Make sure that hash_alg is a supported hash algorithm. Otherwise * we might fail later, which is somewhat unfriendly and potentially * risk-prone. */ psa_status_t status = psa_hash_try_support( hash_alg ); if( status != PSA_SUCCESS ) return( status ); if( ( PSA_ALG_IS_TLS12_PRF( kdf_alg ) || PSA_ALG_IS_TLS12_PSK_TO_MS( kdf_alg ) ) && ! ( hash_alg == PSA_ALG_SHA_256 || hash_alg == PSA_ALG_SHA_384 ) ) { return( PSA_ERROR_NOT_SUPPORTED ); } #if defined(MBEDTLS_PSA_BUILTIN_ALG_HKDF_EXTRACT) if( PSA_ALG_IS_HKDF_EXTRACT( kdf_alg ) ) operation->capacity = hash_size; else #endif /* MBEDTLS_PSA_BUILTIN_ALG_HKDF_EXTRACT */ operation->capacity = 255 * hash_size; return( PSA_SUCCESS ); } static psa_status_t psa_key_agreement_try_support( psa_algorithm_t alg ) { #if defined(PSA_WANT_ALG_ECDH) if( alg == PSA_ALG_ECDH ) return( PSA_SUCCESS ); #endif (void) alg; return( PSA_ERROR_NOT_SUPPORTED ); } #endif /* AT_LEAST_ONE_BUILTIN_KDF */ psa_status_t psa_key_derivation_setup( psa_key_derivation_operation_t *operation, psa_algorithm_t alg ) { psa_status_t status; if( operation->alg != 0 ) return( PSA_ERROR_BAD_STATE ); if( PSA_ALG_IS_RAW_KEY_AGREEMENT( alg ) ) return( PSA_ERROR_INVALID_ARGUMENT ); else if( PSA_ALG_IS_KEY_AGREEMENT( alg ) ) { #if defined(AT_LEAST_ONE_BUILTIN_KDF) psa_algorithm_t kdf_alg = PSA_ALG_KEY_AGREEMENT_GET_KDF( alg ); psa_algorithm_t ka_alg = PSA_ALG_KEY_AGREEMENT_GET_BASE( alg ); status = psa_key_agreement_try_support( ka_alg ); if( status != PSA_SUCCESS ) return( status ); status = psa_key_derivation_setup_kdf( operation, kdf_alg ); #else return( PSA_ERROR_NOT_SUPPORTED ); #endif /* AT_LEAST_ONE_BUILTIN_KDF */ } else if( PSA_ALG_IS_KEY_DERIVATION( alg ) ) { #if defined(AT_LEAST_ONE_BUILTIN_KDF) status = psa_key_derivation_setup_kdf( operation, alg ); #else return( PSA_ERROR_NOT_SUPPORTED ); #endif /* AT_LEAST_ONE_BUILTIN_KDF */ } else return( PSA_ERROR_INVALID_ARGUMENT ); if( status == PSA_SUCCESS ) operation->alg = alg; return( status ); } #if defined(BUILTIN_ALG_ANY_HKDF) static psa_status_t psa_hkdf_input( psa_hkdf_key_derivation_t *hkdf, psa_algorithm_t kdf_alg, psa_key_derivation_step_t step, const uint8_t *data, size_t data_length ) { psa_algorithm_t hash_alg = PSA_ALG_HKDF_GET_HASH( kdf_alg ); psa_status_t status; switch( step ) { case PSA_KEY_DERIVATION_INPUT_SALT: #if defined(MBEDTLS_PSA_BUILTIN_ALG_HKDF_EXPAND) if( PSA_ALG_IS_HKDF_EXPAND( kdf_alg ) ) return( PSA_ERROR_INVALID_ARGUMENT ); #endif /* MBEDTLS_PSA_BUILTIN_ALG_HKDF_EXPAND */ if( hkdf->state != HKDF_STATE_INIT ) return( PSA_ERROR_BAD_STATE ); else { status = psa_key_derivation_start_hmac( &hkdf->hmac, hash_alg, data, data_length ); if( status != PSA_SUCCESS ) return( status ); hkdf->state = HKDF_STATE_STARTED; return( PSA_SUCCESS ); } case PSA_KEY_DERIVATION_INPUT_SECRET: #if defined(MBEDTLS_PSA_BUILTIN_ALG_HKDF_EXPAND) if( PSA_ALG_IS_HKDF_EXPAND( kdf_alg ) ) { /* We shouldn't be in different state as HKDF_EXPAND only allows * two inputs: SECRET (this case) and INFO which does not modify * the state. It could happen only if the hkdf * object was corrupted. */ if( hkdf->state != HKDF_STATE_INIT ) return( PSA_ERROR_BAD_STATE ); /* Allow only input that fits expected prk size */ if( data_length != PSA_HASH_LENGTH( hash_alg ) ) return( PSA_ERROR_INVALID_ARGUMENT ); memcpy( hkdf->prk, data, data_length ); } else #endif /* MBEDTLS_PSA_BUILTIN_ALG_HKDF_EXPAND */ { /* HKDF: If no salt was provided, use an empty salt. * HKDF-EXTRACT: salt is mandatory. */ if( hkdf->state == HKDF_STATE_INIT ) { #if defined(MBEDTLS_PSA_BUILTIN_ALG_HKDF_EXTRACT) if( PSA_ALG_IS_HKDF_EXTRACT( kdf_alg ) ) return( PSA_ERROR_BAD_STATE ); #endif /* MBEDTLS_PSA_BUILTIN_ALG_HKDF_EXTRACT */ status = psa_key_derivation_start_hmac( &hkdf->hmac, hash_alg, NULL, 0 ); if( status != PSA_SUCCESS ) return( status ); hkdf->state = HKDF_STATE_STARTED; } if( hkdf->state != HKDF_STATE_STARTED ) return( PSA_ERROR_BAD_STATE ); status = psa_mac_update( &hkdf->hmac, data, data_length ); if( status != PSA_SUCCESS ) return( status ); status = psa_mac_sign_finish( &hkdf->hmac, hkdf->prk, sizeof( hkdf->prk ), &data_length ); if( status != PSA_SUCCESS ) return( status ); } hkdf->state = HKDF_STATE_KEYED; hkdf->block_number = 0; #if defined(MBEDTLS_PSA_BUILTIN_ALG_HKDF_EXTRACT) if( PSA_ALG_IS_HKDF_EXTRACT( kdf_alg ) ) { /* The only block of output is the PRK. */ memcpy( hkdf->output_block, hkdf->prk, PSA_HASH_LENGTH( hash_alg ) ); hkdf->offset_in_block = 0; } else #endif /* MBEDTLS_PSA_BUILTIN_ALG_HKDF_EXTRACT */ { /* Block 0 is empty, and the next block will be * generated by psa_key_derivation_hkdf_read(). */ hkdf->offset_in_block = PSA_HASH_LENGTH( hash_alg ); } return( PSA_SUCCESS ); case PSA_KEY_DERIVATION_INPUT_INFO: #if defined(MBEDTLS_PSA_BUILTIN_ALG_HKDF_EXTRACT) if( PSA_ALG_IS_HKDF_EXTRACT( kdf_alg ) ) return( PSA_ERROR_INVALID_ARGUMENT ); #endif /* MBEDTLS_PSA_BUILTIN_ALG_HKDF_EXTRACT */ #if defined(MBEDTLS_PSA_BUILTIN_ALG_HKDF_EXPAND) if( PSA_ALG_IS_HKDF_EXPAND( kdf_alg ) && hkdf->state == HKDF_STATE_INIT ) return( PSA_ERROR_BAD_STATE ); #endif /* MBEDTLS_PSA_BUILTIN_ALG_HKDF_EXTRACT */ if( hkdf->state == HKDF_STATE_OUTPUT ) return( PSA_ERROR_BAD_STATE ); if( hkdf->info_set ) return( PSA_ERROR_BAD_STATE ); hkdf->info_length = data_length; if( data_length != 0 ) { hkdf->info = mbedtls_calloc( 1, data_length ); if( hkdf->info == NULL ) return( PSA_ERROR_INSUFFICIENT_MEMORY ); memcpy( hkdf->info, data, data_length ); } hkdf->info_set = 1; return( PSA_SUCCESS ); default: return( PSA_ERROR_INVALID_ARGUMENT ); } } #endif /* BUILTIN_ALG_ANY_HKDF */ #if defined(MBEDTLS_PSA_BUILTIN_ALG_TLS12_PRF) || \ defined(MBEDTLS_PSA_BUILTIN_ALG_TLS12_PSK_TO_MS) static psa_status_t psa_tls12_prf_set_seed( psa_tls12_prf_key_derivation_t *prf, const uint8_t *data, size_t data_length ) { if( prf->state != PSA_TLS12_PRF_STATE_INIT ) return( PSA_ERROR_BAD_STATE ); if( data_length != 0 ) { prf->seed = mbedtls_calloc( 1, data_length ); if( prf->seed == NULL ) return( PSA_ERROR_INSUFFICIENT_MEMORY ); memcpy( prf->seed, data, data_length ); prf->seed_length = data_length; } prf->state = PSA_TLS12_PRF_STATE_SEED_SET; return( PSA_SUCCESS ); } static psa_status_t psa_tls12_prf_set_key( psa_tls12_prf_key_derivation_t *prf, const uint8_t *data, size_t data_length ) { if( prf->state != PSA_TLS12_PRF_STATE_SEED_SET && prf->state != PSA_TLS12_PRF_STATE_OTHER_KEY_SET ) return( PSA_ERROR_BAD_STATE ); if( data_length != 0 ) { prf->secret = mbedtls_calloc( 1, data_length ); if( prf->secret == NULL ) return( PSA_ERROR_INSUFFICIENT_MEMORY ); memcpy( prf->secret, data, data_length ); prf->secret_length = data_length; } prf->state = PSA_TLS12_PRF_STATE_KEY_SET; return( PSA_SUCCESS ); } static psa_status_t psa_tls12_prf_set_label( psa_tls12_prf_key_derivation_t *prf, const uint8_t *data, size_t data_length ) { if( prf->state != PSA_TLS12_PRF_STATE_KEY_SET ) return( PSA_ERROR_BAD_STATE ); if( data_length != 0 ) { prf->label = mbedtls_calloc( 1, data_length ); if( prf->label == NULL ) return( PSA_ERROR_INSUFFICIENT_MEMORY ); memcpy( prf->label, data, data_length ); prf->label_length = data_length; } prf->state = PSA_TLS12_PRF_STATE_LABEL_SET; return( PSA_SUCCESS ); } static psa_status_t psa_tls12_prf_input( psa_tls12_prf_key_derivation_t *prf, psa_key_derivation_step_t step, const uint8_t *data, size_t data_length ) { switch( step ) { case PSA_KEY_DERIVATION_INPUT_SEED: return( psa_tls12_prf_set_seed( prf, data, data_length ) ); case PSA_KEY_DERIVATION_INPUT_SECRET: return( psa_tls12_prf_set_key( prf, data, data_length ) ); case PSA_KEY_DERIVATION_INPUT_LABEL: return( psa_tls12_prf_set_label( prf, data, data_length ) ); default: return( PSA_ERROR_INVALID_ARGUMENT ); } } #endif /* MBEDTLS_PSA_BUILTIN_ALG_TLS12_PRF) || * MBEDTLS_PSA_BUILTIN_ALG_TLS12_PSK_TO_MS */ #if defined(MBEDTLS_PSA_BUILTIN_ALG_TLS12_PSK_TO_MS) static psa_status_t psa_tls12_prf_psk_to_ms_set_key( psa_tls12_prf_key_derivation_t *prf, const uint8_t *data, size_t data_length ) { psa_status_t status; const size_t pms_len = ( prf->state == PSA_TLS12_PRF_STATE_OTHER_KEY_SET ? 4 + data_length + prf->other_secret_length : 4 + 2 * data_length ); if( data_length > PSA_TLS12_PSK_TO_MS_PSK_MAX_SIZE ) return( PSA_ERROR_INVALID_ARGUMENT ); uint8_t *pms = mbedtls_calloc( 1, pms_len ); if( pms == NULL ) return( PSA_ERROR_INSUFFICIENT_MEMORY ); uint8_t *cur = pms; /* pure-PSK: * Quoting RFC 4279, Section 2: * * The premaster secret is formed as follows: if the PSK is N octets * long, concatenate a uint16 with the value N, N zero octets, a second * uint16 with the value N, and the PSK itself. * * mixed-PSK: * In a DHE-PSK, RSA-PSK, ECDHE-PSK the premaster secret is formed as * follows: concatenate a uint16 with the length of the other secret, * the other secret itself, uint16 with the length of PSK, and the * PSK itself. * For details please check: * - RFC 4279, Section 4 for the definition of RSA-PSK, * - RFC 4279, Section 3 for the definition of DHE-PSK, * - RFC 5489 for the definition of ECDHE-PSK. */ if( prf->state == PSA_TLS12_PRF_STATE_OTHER_KEY_SET ) { *cur++ = MBEDTLS_BYTE_1( prf->other_secret_length ); *cur++ = MBEDTLS_BYTE_0( prf->other_secret_length ); if( prf->other_secret_length != 0 ) { memcpy( cur, prf->other_secret, prf->other_secret_length ); mbedtls_platform_zeroize( prf->other_secret, prf->other_secret_length ); cur += prf->other_secret_length; } } else { *cur++ = MBEDTLS_BYTE_1( data_length ); *cur++ = MBEDTLS_BYTE_0( data_length ); memset( cur, 0, data_length ); cur += data_length; } *cur++ = MBEDTLS_BYTE_1( data_length ); *cur++ = MBEDTLS_BYTE_0( data_length ); memcpy( cur, data, data_length ); cur += data_length; status = psa_tls12_prf_set_key( prf, pms, cur - pms ); mbedtls_platform_zeroize( pms, pms_len ); mbedtls_free( pms ); return( status ); } static psa_status_t psa_tls12_prf_psk_to_ms_set_other_key( psa_tls12_prf_key_derivation_t *prf, const uint8_t *data, size_t data_length ) { if( prf->state != PSA_TLS12_PRF_STATE_SEED_SET ) return( PSA_ERROR_BAD_STATE ); if( data_length != 0 ) { prf->other_secret = mbedtls_calloc( 1, data_length ); if( prf->other_secret == NULL ) return( PSA_ERROR_INSUFFICIENT_MEMORY ); memcpy( prf->other_secret, data, data_length ); prf->other_secret_length = data_length; } else { prf->other_secret_length = 0; } prf->state = PSA_TLS12_PRF_STATE_OTHER_KEY_SET; return( PSA_SUCCESS ); } static psa_status_t psa_tls12_prf_psk_to_ms_input( psa_tls12_prf_key_derivation_t *prf, psa_key_derivation_step_t step, const uint8_t *data, size_t data_length ) { switch( step ) { case PSA_KEY_DERIVATION_INPUT_SECRET: return( psa_tls12_prf_psk_to_ms_set_key( prf, data, data_length ) ); break; case PSA_KEY_DERIVATION_INPUT_OTHER_SECRET: return( psa_tls12_prf_psk_to_ms_set_other_key( prf, data, data_length ) ); break; default: return( psa_tls12_prf_input( prf, step, data, data_length ) ); break; } } #endif /* MBEDTLS_PSA_BUILTIN_ALG_TLS12_PSK_TO_MS */ /** Check whether the given key type is acceptable for the given * input step of a key derivation. * * Secret inputs must have the type #PSA_KEY_TYPE_DERIVE. * Non-secret inputs must have the type #PSA_KEY_TYPE_RAW_DATA. * Both secret and non-secret inputs can alternatively have the type * #PSA_KEY_TYPE_NONE, which is never the type of a key object, meaning * that the input was passed as a buffer rather than via a key object. */ static int psa_key_derivation_check_input_type( psa_key_derivation_step_t step, psa_key_type_t key_type ) { switch( step ) { case PSA_KEY_DERIVATION_INPUT_SECRET: if( key_type == PSA_KEY_TYPE_DERIVE ) return( PSA_SUCCESS ); if( key_type == PSA_KEY_TYPE_NONE ) return( PSA_SUCCESS ); break; case PSA_KEY_DERIVATION_INPUT_OTHER_SECRET: if( key_type == PSA_KEY_TYPE_DERIVE ) return( PSA_SUCCESS ); if( key_type == PSA_KEY_TYPE_NONE ) return( PSA_SUCCESS ); break; case PSA_KEY_DERIVATION_INPUT_LABEL: case PSA_KEY_DERIVATION_INPUT_SALT: case PSA_KEY_DERIVATION_INPUT_INFO: case PSA_KEY_DERIVATION_INPUT_SEED: if( key_type == PSA_KEY_TYPE_RAW_DATA ) return( PSA_SUCCESS ); if( key_type == PSA_KEY_TYPE_NONE ) return( PSA_SUCCESS ); break; } return( PSA_ERROR_INVALID_ARGUMENT ); } static psa_status_t psa_key_derivation_input_internal( psa_key_derivation_operation_t *operation, psa_key_derivation_step_t step, psa_key_type_t key_type, const uint8_t *data, size_t data_length ) { psa_status_t status; psa_algorithm_t kdf_alg = psa_key_derivation_get_kdf_alg( operation ); status = psa_key_derivation_check_input_type( step, key_type ); if( status != PSA_SUCCESS ) goto exit; #if defined(BUILTIN_ALG_ANY_HKDF) if( PSA_ALG_IS_ANY_HKDF( kdf_alg ) ) { status = psa_hkdf_input( &operation->ctx.hkdf, kdf_alg, step, data, data_length ); } else #endif /* BUILTIN_ALG_ANY_HKDF */ #if defined(MBEDTLS_PSA_BUILTIN_ALG_TLS12_PRF) if( PSA_ALG_IS_TLS12_PRF( kdf_alg ) ) { status = psa_tls12_prf_input( &operation->ctx.tls12_prf, step, data, data_length ); } else #endif /* MBEDTLS_PSA_BUILTIN_ALG_TLS12_PRF */ #if defined(MBEDTLS_PSA_BUILTIN_ALG_TLS12_PSK_TO_MS) if( PSA_ALG_IS_TLS12_PSK_TO_MS( kdf_alg ) ) { status = psa_tls12_prf_psk_to_ms_input( &operation->ctx.tls12_prf, step, data, data_length ); } else #endif /* MBEDTLS_PSA_BUILTIN_ALG_TLS12_PSK_TO_MS */ { /* This can't happen unless the operation object was not initialized */ (void) data; (void) data_length; (void) kdf_alg; return( PSA_ERROR_BAD_STATE ); } exit: if( status != PSA_SUCCESS ) psa_key_derivation_abort( operation ); return( status ); } psa_status_t psa_key_derivation_input_bytes( psa_key_derivation_operation_t *operation, psa_key_derivation_step_t step, const uint8_t *data, size_t data_length ) { return( psa_key_derivation_input_internal( operation, step, PSA_KEY_TYPE_NONE, data, data_length ) ); } psa_status_t psa_key_derivation_input_key( psa_key_derivation_operation_t *operation, psa_key_derivation_step_t step, mbedtls_svc_key_id_t key ) { psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED; psa_status_t unlock_status = PSA_ERROR_CORRUPTION_DETECTED; psa_key_slot_t *slot; status = psa_get_and_lock_transparent_key_slot_with_policy( key, &slot, PSA_KEY_USAGE_DERIVE, operation->alg ); if( status != PSA_SUCCESS ) { psa_key_derivation_abort( operation ); return( status ); } /* Passing a key object as a SECRET input unlocks the permission * to output to a key object. */ if( step == PSA_KEY_DERIVATION_INPUT_SECRET ) operation->can_output_key = 1; status = psa_key_derivation_input_internal( operation, step, slot->attr.type, slot->key.data, slot->key.bytes ); unlock_status = psa_unlock_key_slot( slot ); return( ( status == PSA_SUCCESS ) ? unlock_status : status ); } /****************************************************************/ /* Key agreement */ /****************************************************************/ #if defined(MBEDTLS_PSA_BUILTIN_ALG_ECDH) static psa_status_t psa_key_agreement_ecdh( const uint8_t *peer_key, size_t peer_key_length, const mbedtls_ecp_keypair *our_key, uint8_t *shared_secret, size_t shared_secret_size, size_t *shared_secret_length ) { mbedtls_ecp_keypair *their_key = NULL; mbedtls_ecdh_context ecdh; psa_status_t status; size_t bits = 0; psa_ecc_family_t curve = mbedtls_ecc_group_to_psa( our_key->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, our_key, 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 ); return( status ); } #endif /* MBEDTLS_PSA_BUILTIN_ALG_ECDH */ #define PSA_KEY_AGREEMENT_MAX_SHARED_SECRET_SIZE MBEDTLS_ECP_MAX_BYTES static psa_status_t psa_key_agreement_raw_internal( psa_algorithm_t alg, psa_key_slot_t *private_key, const uint8_t *peer_key, size_t peer_key_length, uint8_t *shared_secret, size_t shared_secret_size, size_t *shared_secret_length ) { switch( alg ) { #if defined(MBEDTLS_PSA_BUILTIN_ALG_ECDH) case PSA_ALG_ECDH: if( ! PSA_KEY_TYPE_IS_ECC_KEY_PAIR( private_key->attr.type ) ) return( PSA_ERROR_INVALID_ARGUMENT ); mbedtls_ecp_keypair *ecp = NULL; psa_status_t status = mbedtls_psa_ecp_load_representation( private_key->attr.type, private_key->attr.bits, private_key->key.data, private_key->key.bytes, &ecp ); if( status != PSA_SUCCESS ) return( status ); status = psa_key_agreement_ecdh( peer_key, peer_key_length, ecp, shared_secret, shared_secret_size, shared_secret_length ); mbedtls_ecp_keypair_free( ecp ); mbedtls_free( ecp ); return( status ); #endif /* MBEDTLS_PSA_BUILTIN_ALG_ECDH */ default: (void) private_key; (void) peer_key; (void) peer_key_length; (void) shared_secret; (void) shared_secret_size; (void) shared_secret_length; return( PSA_ERROR_NOT_SUPPORTED ); } } /* Note that if this function fails, you must call psa_key_derivation_abort() * to potentially free embedded data structures and wipe confidential data. */ static psa_status_t psa_key_agreement_internal( psa_key_derivation_operation_t *operation, psa_key_derivation_step_t step, psa_key_slot_t *private_key, const uint8_t *peer_key, size_t peer_key_length ) { psa_status_t status; uint8_t shared_secret[PSA_KEY_AGREEMENT_MAX_SHARED_SECRET_SIZE]; size_t shared_secret_length = 0; psa_algorithm_t ka_alg = PSA_ALG_KEY_AGREEMENT_GET_BASE( operation->alg ); /* Step 1: run the secret agreement algorithm to generate the shared * secret. */ status = psa_key_agreement_raw_internal( ka_alg, private_key, peer_key, peer_key_length, shared_secret, sizeof( shared_secret ), &shared_secret_length ); if( status != PSA_SUCCESS ) goto exit; /* Step 2: set up the key derivation to generate key material from * the shared secret. A shared secret is permitted wherever a key * of type DERIVE is permitted. */ status = psa_key_derivation_input_internal( operation, step, PSA_KEY_TYPE_DERIVE, shared_secret, shared_secret_length ); exit: mbedtls_platform_zeroize( shared_secret, shared_secret_length ); return( status ); } psa_status_t psa_key_derivation_key_agreement( psa_key_derivation_operation_t *operation, psa_key_derivation_step_t step, mbedtls_svc_key_id_t private_key, const uint8_t *peer_key, size_t peer_key_length ) { psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED; psa_status_t unlock_status = PSA_ERROR_CORRUPTION_DETECTED; psa_key_slot_t *slot; if( ! PSA_ALG_IS_KEY_AGREEMENT( operation->alg ) ) return( PSA_ERROR_INVALID_ARGUMENT ); status = psa_get_and_lock_transparent_key_slot_with_policy( private_key, &slot, PSA_KEY_USAGE_DERIVE, operation->alg ); if( status != PSA_SUCCESS ) return( status ); status = psa_key_agreement_internal( operation, step, slot, peer_key, peer_key_length ); if( status != PSA_SUCCESS ) psa_key_derivation_abort( operation ); else { /* If a private key has been added as SECRET, we allow the derived * key material to be used as a key in PSA Crypto. */ if( step == PSA_KEY_DERIVATION_INPUT_SECRET ) operation->can_output_key = 1; } unlock_status = psa_unlock_key_slot( slot ); return( ( status == PSA_SUCCESS ) ? unlock_status : status ); } psa_status_t psa_raw_key_agreement( psa_algorithm_t alg, mbedtls_svc_key_id_t private_key, const uint8_t *peer_key, size_t peer_key_length, uint8_t *output, size_t output_size, size_t *output_length ) { psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED; psa_status_t unlock_status = PSA_ERROR_CORRUPTION_DETECTED; psa_key_slot_t *slot = NULL; if( ! PSA_ALG_IS_KEY_AGREEMENT( alg ) ) { status = PSA_ERROR_INVALID_ARGUMENT; goto exit; } status = psa_get_and_lock_transparent_key_slot_with_policy( private_key, &slot, PSA_KEY_USAGE_DERIVE, alg ); if( status != PSA_SUCCESS ) goto exit; /* PSA_RAW_KEY_AGREEMENT_OUTPUT_SIZE() is in general an upper bound * for the output size. The PSA specification only guarantees that this * function works if output_size >= PSA_RAW_KEY_AGREEMENT_OUTPUT_SIZE(...), * but it might be nice to allow smaller buffers if the output fits. * At the time of writing this comment, with only ECDH implemented, * PSA_RAW_KEY_AGREEMENT_OUTPUT_SIZE() is exact so the point is moot. * If FFDH is implemented, PSA_RAW_KEY_AGREEMENT_OUTPUT_SIZE() can easily * be exact for it as well. */ size_t expected_length = PSA_RAW_KEY_AGREEMENT_OUTPUT_SIZE( slot->attr.type, slot->attr.bits ); if( output_size < expected_length ) { status = PSA_ERROR_BUFFER_TOO_SMALL; goto exit; } status = psa_key_agreement_raw_internal( alg, slot, peer_key, peer_key_length, output, output_size, output_length ); exit: if( status != PSA_SUCCESS ) { /* If an error happens and is not handled properly, the output * may be used as a key to protect sensitive data. Arrange for such * a key to be random, which is likely to result in decryption or * verification errors. This is better than filling the buffer with * some constant data such as zeros, which would result in the data * being protected with a reproducible, easily knowable key. */ psa_generate_random( output, output_size ); *output_length = output_size; } unlock_status = psa_unlock_key_slot( slot ); return( ( status == PSA_SUCCESS ) ? unlock_status : status ); } /****************************************************************/ /* Random generation */ /****************************************************************/ /** Initialize the PSA random generator. */ static void mbedtls_psa_random_init( mbedtls_psa_random_context_t *rng ) { #if defined(MBEDTLS_PSA_CRYPTO_EXTERNAL_RNG) memset( rng, 0, sizeof( *rng ) ); #else /* MBEDTLS_PSA_CRYPTO_EXTERNAL_RNG */ /* Set default configuration if * mbedtls_psa_crypto_configure_entropy_sources() hasn't been called. */ if( rng->entropy_init == NULL ) rng->entropy_init = mbedtls_entropy_init; if( rng->entropy_free == NULL ) rng->entropy_free = mbedtls_entropy_free; rng->entropy_init( &rng->entropy ); #if defined(MBEDTLS_PSA_INJECT_ENTROPY) && \ defined(MBEDTLS_NO_DEFAULT_ENTROPY_SOURCES) /* The PSA entropy injection feature depends on using NV seed as an entropy * source. Add NV seed as an entropy source for PSA entropy injection. */ mbedtls_entropy_add_source( &rng->entropy, mbedtls_nv_seed_poll, NULL, MBEDTLS_ENTROPY_BLOCK_SIZE, MBEDTLS_ENTROPY_SOURCE_STRONG ); #endif mbedtls_psa_drbg_init( MBEDTLS_PSA_RANDOM_STATE ); #endif /* MBEDTLS_PSA_CRYPTO_EXTERNAL_RNG */ } /** Deinitialize the PSA random generator. */ static void mbedtls_psa_random_free( mbedtls_psa_random_context_t *rng ) { #if defined(MBEDTLS_PSA_CRYPTO_EXTERNAL_RNG) memset( rng, 0, sizeof( *rng ) ); #else /* MBEDTLS_PSA_CRYPTO_EXTERNAL_RNG */ mbedtls_psa_drbg_free( MBEDTLS_PSA_RANDOM_STATE ); rng->entropy_free( &rng->entropy ); #endif /* MBEDTLS_PSA_CRYPTO_EXTERNAL_RNG */ } /** Seed the PSA random generator. */ static psa_status_t mbedtls_psa_random_seed( mbedtls_psa_random_context_t *rng ) { #if defined(MBEDTLS_PSA_CRYPTO_EXTERNAL_RNG) /* Do nothing: the external RNG seeds itself. */ (void) rng; return( PSA_SUCCESS ); #else /* MBEDTLS_PSA_CRYPTO_EXTERNAL_RNG */ const unsigned char drbg_seed[] = "PSA"; int ret = mbedtls_psa_drbg_seed( &rng->entropy, drbg_seed, sizeof( drbg_seed ) - 1 ); return mbedtls_to_psa_error( ret ); #endif /* MBEDTLS_PSA_CRYPTO_EXTERNAL_RNG */ } psa_status_t psa_generate_random( uint8_t *output, size_t output_size ) { GUARD_MODULE_INITIALIZED; #if defined(MBEDTLS_PSA_CRYPTO_EXTERNAL_RNG) size_t output_length = 0; psa_status_t status = mbedtls_psa_external_get_random( &global_data.rng, output, output_size, &output_length ); if( status != PSA_SUCCESS ) return( status ); /* Breaking up a request into smaller chunks is currently not supported * for the extrernal RNG interface. */ if( output_length != output_size ) return( PSA_ERROR_INSUFFICIENT_ENTROPY ); return( PSA_SUCCESS ); #else /* MBEDTLS_PSA_CRYPTO_EXTERNAL_RNG */ while( output_size > 0 ) { size_t request_size = ( output_size > MBEDTLS_PSA_RANDOM_MAX_REQUEST ? MBEDTLS_PSA_RANDOM_MAX_REQUEST : output_size ); int ret = mbedtls_psa_get_random( MBEDTLS_PSA_RANDOM_STATE, output, request_size ); if( ret != 0 ) return( mbedtls_to_psa_error( ret ) ); output_size -= request_size; output += request_size; } return( PSA_SUCCESS ); #endif /* MBEDTLS_PSA_CRYPTO_EXTERNAL_RNG */ } /* Wrapper function allowing the classic API to use the PSA RNG. * * `mbedtls_psa_get_random(MBEDTLS_PSA_RANDOM_STATE, ...)` calls * `psa_generate_random(...)`. The state parameter is ignored since the * PSA API doesn't support passing an explicit state. * * In the non-external case, psa_generate_random() calls an * `mbedtls_xxx_drbg_random` function which has exactly the same signature * and semantics as mbedtls_psa_get_random(). As an optimization, * instead of doing this back-and-forth between the PSA API and the * classic API, psa_crypto_random_impl.h defines `mbedtls_psa_get_random` * as a constant function pointer to `mbedtls_xxx_drbg_random`. */ #if defined (MBEDTLS_PSA_CRYPTO_EXTERNAL_RNG) int mbedtls_psa_get_random( void *p_rng, unsigned char *output, size_t output_size ) { /* This function takes a pointer to the RNG state because that's what * classic mbedtls functions using an RNG expect. The PSA RNG manages * its own state internally and doesn't let the caller access that state. * So we just ignore the state parameter, and in practice we'll pass * NULL. */ (void) p_rng; psa_status_t status = psa_generate_random( output, output_size ); if( status == PSA_SUCCESS ) return( 0 ); else return( MBEDTLS_ERR_ENTROPY_SOURCE_FAILED ); } #endif /* MBEDTLS_PSA_CRYPTO_EXTERNAL_RNG */ #if defined(MBEDTLS_PSA_INJECT_ENTROPY) #include "entropy_poll.h" psa_status_t mbedtls_psa_inject_entropy( const uint8_t *seed, size_t seed_size ) { if( global_data.initialized ) return( PSA_ERROR_NOT_PERMITTED ); if( ( ( seed_size < MBEDTLS_ENTROPY_MIN_PLATFORM ) || ( seed_size < MBEDTLS_ENTROPY_BLOCK_SIZE ) ) || ( seed_size > MBEDTLS_ENTROPY_MAX_SEED_SIZE ) ) return( PSA_ERROR_INVALID_ARGUMENT ); return( mbedtls_psa_storage_inject_entropy( seed, seed_size ) ); } #endif /* MBEDTLS_PSA_INJECT_ENTROPY */ /** Validate the key type and size for key generation * * \param type The key type * \param bits The number of bits of the key * * \retval #PSA_SUCCESS * The key type and size are valid. * \retval #PSA_ERROR_INVALID_ARGUMENT * The size in bits of the key is not valid. * \retval #PSA_ERROR_NOT_SUPPORTED * The type and/or the size in bits of the key or the combination of * the two is not supported. */ static psa_status_t psa_validate_key_type_and_size_for_key_generation( psa_key_type_t type, size_t bits ) { psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED; if( key_type_is_raw_bytes( type ) ) { status = psa_validate_unstructured_key_bit_size( type, bits ); if( status != PSA_SUCCESS ) return( status ); } else #if defined(PSA_WANT_KEY_TYPE_RSA_KEY_PAIR) if( PSA_KEY_TYPE_IS_RSA( type ) && PSA_KEY_TYPE_IS_KEY_PAIR( type ) ) { if( bits > PSA_VENDOR_RSA_MAX_KEY_BITS ) return( PSA_ERROR_NOT_SUPPORTED ); /* Accept only byte-aligned keys, for the same reasons as * in psa_import_rsa_key(). */ if( bits % 8 != 0 ) return( PSA_ERROR_NOT_SUPPORTED ); } else #endif /* defined(PSA_WANT_KEY_TYPE_RSA_KEY_PAIR) */ #if defined(PSA_WANT_KEY_TYPE_ECC_KEY_PAIR) if( PSA_KEY_TYPE_IS_ECC( type ) && PSA_KEY_TYPE_IS_KEY_PAIR( type ) ) { /* To avoid empty block, return successfully here. */ return( PSA_SUCCESS ); } else #endif /* defined(PSA_WANT_KEY_TYPE_ECC_KEY_PAIR) */ { return( PSA_ERROR_NOT_SUPPORTED ); } return( PSA_SUCCESS ); } psa_status_t psa_generate_key_internal( 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; psa_key_type_t type = attributes->core.type; if( ( attributes->domain_parameters == NULL ) && ( attributes->domain_parameters_size != 0 ) ) return( PSA_ERROR_INVALID_ARGUMENT ); if( key_type_is_raw_bytes( type ) ) { status = psa_generate_random( key_buffer, key_buffer_size ); if( status != PSA_SUCCESS ) return( status ); #if defined(MBEDTLS_PSA_BUILTIN_KEY_TYPE_DES) if( type == PSA_KEY_TYPE_DES ) psa_des_set_key_parity( key_buffer, key_buffer_size ); #endif /* MBEDTLS_PSA_BUILTIN_KEY_TYPE_DES */ } else #if defined(MBEDTLS_PSA_BUILTIN_KEY_TYPE_RSA_KEY_PAIR) && \ defined(MBEDTLS_GENPRIME) if ( type == PSA_KEY_TYPE_RSA_KEY_PAIR ) { return( mbedtls_psa_rsa_generate_key( attributes, key_buffer, key_buffer_size, key_buffer_length ) ); } else #endif /* defined(MBEDTLS_PSA_BUILTIN_KEY_TYPE_RSA_KEY_PAIR) * defined(MBEDTLS_GENPRIME) */ #if defined(MBEDTLS_PSA_BUILTIN_KEY_TYPE_ECC_KEY_PAIR) if ( PSA_KEY_TYPE_IS_ECC( type ) && PSA_KEY_TYPE_IS_KEY_PAIR( type ) ) { return( mbedtls_psa_ecp_generate_key( attributes, key_buffer, key_buffer_size, key_buffer_length ) ); } else #endif /* defined(MBEDTLS_PSA_BUILTIN_KEY_TYPE_ECC_KEY_PAIR) */ { (void)key_buffer_length; return( PSA_ERROR_NOT_SUPPORTED ); } return( PSA_SUCCESS ); } psa_status_t psa_generate_key( const psa_key_attributes_t *attributes, mbedtls_svc_key_id_t *key ) { psa_status_t status; psa_key_slot_t *slot = NULL; psa_se_drv_table_entry_t *driver = NULL; size_t key_buffer_size; *key = MBEDTLS_SVC_KEY_ID_INIT; /* Reject any attempt to create a zero-length key so that we don't * risk tripping up later, e.g. on a malloc(0) that returns NULL. */ if( psa_get_key_bits( attributes ) == 0 ) return( PSA_ERROR_INVALID_ARGUMENT ); /* Reject any attempt to create a public key. */ if( PSA_KEY_TYPE_IS_PUBLIC_KEY(attributes->core.type) ) return( PSA_ERROR_INVALID_ARGUMENT ); status = psa_start_key_creation( PSA_KEY_CREATION_GENERATE, attributes, &slot, &driver ); if( status != PSA_SUCCESS ) goto exit; /* In the case of a transparent key or an opaque key stored in local * storage ( thus not in the case of generating a key in a secure element * with storage ( MBEDTLS_PSA_CRYPTO_SE_C ) ),we have to allocate a * buffer to hold the generated key material. */ if( slot->key.data == NULL ) { if ( PSA_KEY_LIFETIME_GET_LOCATION( attributes->core.lifetime ) == PSA_KEY_LOCATION_LOCAL_STORAGE ) { status = psa_validate_key_type_and_size_for_key_generation( attributes->core.type, attributes->core.bits ); if( status != PSA_SUCCESS ) goto exit; key_buffer_size = PSA_EXPORT_KEY_OUTPUT_SIZE( attributes->core.type, attributes->core.bits ); } else { status = psa_driver_wrapper_get_key_buffer_size( attributes, &key_buffer_size ); if( status != PSA_SUCCESS ) goto exit; } status = psa_allocate_buffer_to_slot( slot, key_buffer_size ); if( status != PSA_SUCCESS ) goto exit; } status = psa_driver_wrapper_generate_key( attributes, slot->key.data, slot->key.bytes, &slot->key.bytes ); if( status != PSA_SUCCESS ) psa_remove_key_data_from_memory( slot ); exit: if( status == PSA_SUCCESS ) status = psa_finish_key_creation( slot, driver, key ); if( status != PSA_SUCCESS ) psa_fail_key_creation( slot, driver ); return( status ); } /****************************************************************/ /* Module setup */ /****************************************************************/ #if !defined(MBEDTLS_PSA_CRYPTO_EXTERNAL_RNG) psa_status_t mbedtls_psa_crypto_configure_entropy_sources( void (* entropy_init )( mbedtls_entropy_context *ctx ), void (* entropy_free )( mbedtls_entropy_context *ctx ) ) { if( global_data.rng_state != RNG_NOT_INITIALIZED ) return( PSA_ERROR_BAD_STATE ); global_data.rng.entropy_init = entropy_init; global_data.rng.entropy_free = entropy_free; return( PSA_SUCCESS ); } #endif /* !defined(MBEDTLS_PSA_CRYPTO_EXTERNAL_RNG) */ void mbedtls_psa_crypto_free( void ) { psa_wipe_all_key_slots( ); if( global_data.rng_state != RNG_NOT_INITIALIZED ) { mbedtls_psa_random_free( &global_data.rng ); } /* Wipe all remaining data, including configuration. * In particular, this sets all state indicator to the value * indicating "uninitialized". */ mbedtls_platform_zeroize( &global_data, sizeof( global_data ) ); /* Terminate drivers */ psa_driver_wrapper_free( ); } #if defined(PSA_CRYPTO_STORAGE_HAS_TRANSACTIONS) /** Recover a transaction that was interrupted by a power failure. * * This function is called during initialization, before psa_crypto_init() * returns. If this function returns a failure status, the initialization * fails. */ static psa_status_t psa_crypto_recover_transaction( const psa_crypto_transaction_t *transaction ) { switch( transaction->unknown.type ) { case PSA_CRYPTO_TRANSACTION_CREATE_KEY: case PSA_CRYPTO_TRANSACTION_DESTROY_KEY: /* TODO - fall through to the failure case until this * is implemented. * https://github.com/ARMmbed/mbed-crypto/issues/218 */ default: /* We found an unsupported transaction in the storage. * We don't know what state the storage is in. Give up. */ return( PSA_ERROR_DATA_INVALID ); } } #endif /* PSA_CRYPTO_STORAGE_HAS_TRANSACTIONS */ psa_status_t psa_crypto_init( void ) { psa_status_t status; /* Double initialization is explicitly allowed. */ if( global_data.initialized != 0 ) return( PSA_SUCCESS ); /* Initialize and seed the random generator. */ mbedtls_psa_random_init( &global_data.rng ); global_data.rng_state = RNG_INITIALIZED; status = mbedtls_psa_random_seed( &global_data.rng ); if( status != PSA_SUCCESS ) goto exit; global_data.rng_state = RNG_SEEDED; status = psa_initialize_key_slots( ); if( status != PSA_SUCCESS ) goto exit; /* Init drivers */ status = psa_driver_wrapper_init( ); if( status != PSA_SUCCESS ) goto exit; #if defined(PSA_CRYPTO_STORAGE_HAS_TRANSACTIONS) status = psa_crypto_load_transaction( ); if( status == PSA_SUCCESS ) { status = psa_crypto_recover_transaction( &psa_crypto_transaction ); if( status != PSA_SUCCESS ) goto exit; status = psa_crypto_stop_transaction( ); } else if( status == PSA_ERROR_DOES_NOT_EXIST ) { /* There's no transaction to complete. It's all good. */ status = PSA_SUCCESS; } #endif /* PSA_CRYPTO_STORAGE_HAS_TRANSACTIONS */ /* All done. */ global_data.initialized = 1; exit: if( status != PSA_SUCCESS ) mbedtls_psa_crypto_free( ); return( status ); } #endif /* MBEDTLS_PSA_CRYPTO_C */