psa_crypto_random_impl.h (4131B)
1 /** \file psa_crypto_random_impl.h 2 * 3 * \brief PSA crypto random generator implementation abstraction. 4 */ 5 /* 6 * Copyright The Mbed TLS Contributors 7 * SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later 8 */ 9 10 #ifndef PSA_CRYPTO_RANDOM_IMPL_H 11 #define PSA_CRYPTO_RANDOM_IMPL_H 12 13 #include "psa_util_internal.h" 14 15 #if defined(MBEDTLS_PSA_CRYPTO_EXTERNAL_RNG) 16 17 typedef mbedtls_psa_external_random_context_t mbedtls_psa_random_context_t; 18 19 #else /* MBEDTLS_PSA_CRYPTO_EXTERNAL_RNG */ 20 21 #include "mbedtls/entropy.h" 22 23 /* Choose a DRBG based on configuration and availability */ 24 #if defined(MBEDTLS_CTR_DRBG_C) 25 26 #include "mbedtls/ctr_drbg.h" 27 #undef MBEDTLS_PSA_HMAC_DRBG_MD_TYPE 28 29 #elif defined(MBEDTLS_HMAC_DRBG_C) 30 31 #include "mbedtls/hmac_drbg.h" 32 #if defined(MBEDTLS_MD_CAN_SHA512) && defined(MBEDTLS_MD_CAN_SHA256) 33 #include <limits.h> 34 #if SIZE_MAX > 0xffffffff 35 /* Looks like a 64-bit system, so prefer SHA-512. */ 36 #define MBEDTLS_PSA_HMAC_DRBG_MD_TYPE MBEDTLS_MD_SHA512 37 #else 38 /* Looks like a 32-bit system, so prefer SHA-256. */ 39 #define MBEDTLS_PSA_HMAC_DRBG_MD_TYPE MBEDTLS_MD_SHA256 40 #endif 41 #elif defined(MBEDTLS_MD_CAN_SHA512) 42 #define MBEDTLS_PSA_HMAC_DRBG_MD_TYPE MBEDTLS_MD_SHA512 43 #elif defined(MBEDTLS_MD_CAN_SHA256) 44 #define MBEDTLS_PSA_HMAC_DRBG_MD_TYPE MBEDTLS_MD_SHA256 45 #else 46 #error "No hash algorithm available for HMAC_DBRG." 47 #endif 48 49 #else /* !MBEDTLS_CTR_DRBG_C && !MBEDTLS_HMAC_DRBG_C*/ 50 51 #error "No DRBG module available for the psa_crypto module." 52 53 #endif /* !MBEDTLS_CTR_DRBG_C && !MBEDTLS_HMAC_DRBG_C*/ 54 55 /* The maximum number of bytes that mbedtls_psa_get_random() is expected to return. */ 56 #if defined(MBEDTLS_CTR_DRBG_C) 57 #define MBEDTLS_PSA_RANDOM_MAX_REQUEST MBEDTLS_CTR_DRBG_MAX_REQUEST 58 #elif defined(MBEDTLS_HMAC_DRBG_C) 59 #define MBEDTLS_PSA_RANDOM_MAX_REQUEST MBEDTLS_HMAC_DRBG_MAX_REQUEST 60 #endif 61 62 #if defined(MBEDTLS_CTR_DRBG_C) 63 typedef mbedtls_ctr_drbg_context mbedtls_psa_drbg_context_t; 64 #elif defined(MBEDTLS_HMAC_DRBG_C) 65 typedef mbedtls_hmac_drbg_context mbedtls_psa_drbg_context_t; 66 #endif /* !MBEDTLS_CTR_DRBG_C && !MBEDTLS_HMAC_DRBG_C */ 67 68 typedef struct { 69 void (* entropy_init)(mbedtls_entropy_context *ctx); 70 void (* entropy_free)(mbedtls_entropy_context *ctx); 71 mbedtls_entropy_context entropy; 72 mbedtls_psa_drbg_context_t drbg; 73 } mbedtls_psa_random_context_t; 74 75 /** Initialize the PSA DRBG. 76 * 77 * \param p_rng Pointer to the Mbed TLS DRBG state. 78 */ 79 static inline void mbedtls_psa_drbg_init(mbedtls_psa_drbg_context_t *p_rng) 80 { 81 #if defined(MBEDTLS_CTR_DRBG_C) 82 mbedtls_ctr_drbg_init(p_rng); 83 #elif defined(MBEDTLS_HMAC_DRBG_C) 84 mbedtls_hmac_drbg_init(p_rng); 85 #endif 86 } 87 88 /** Deinitialize the PSA DRBG. 89 * 90 * \param p_rng Pointer to the Mbed TLS DRBG state. 91 */ 92 static inline void mbedtls_psa_drbg_free(mbedtls_psa_drbg_context_t *p_rng) 93 { 94 #if defined(MBEDTLS_CTR_DRBG_C) 95 mbedtls_ctr_drbg_free(p_rng); 96 #elif defined(MBEDTLS_HMAC_DRBG_C) 97 mbedtls_hmac_drbg_free(p_rng); 98 #endif 99 } 100 101 /** Seed the PSA DRBG. 102 * 103 * \param entropy An entropy context to read the seed from. 104 * \param custom The personalization string. 105 * This can be \c NULL, in which case the personalization 106 * string is empty regardless of the value of \p len. 107 * \param len The length of the personalization string. 108 * 109 * \return \c 0 on success. 110 * \return An Mbed TLS error code (\c MBEDTLS_ERR_xxx) on failure. 111 */ 112 static inline int mbedtls_psa_drbg_seed(mbedtls_psa_drbg_context_t *drbg_ctx, 113 mbedtls_entropy_context *entropy, 114 const unsigned char *custom, size_t len) 115 { 116 #if defined(MBEDTLS_CTR_DRBG_C) 117 return mbedtls_ctr_drbg_seed(drbg_ctx, mbedtls_entropy_func, entropy, custom, len); 118 #elif defined(MBEDTLS_HMAC_DRBG_C) 119 const mbedtls_md_info_t *md_info = mbedtls_md_info_from_type(MBEDTLS_PSA_HMAC_DRBG_MD_TYPE); 120 return mbedtls_hmac_drbg_seed(drbg_ctx, md_info, mbedtls_entropy_func, entropy, custom, len); 121 #endif 122 } 123 124 #endif /* MBEDTLS_PSA_CRYPTO_EXTERNAL_RNG */ 125 126 #endif /* PSA_CRYPTO_RANDOM_IMPL_H */