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_PSA_HMAC_DRBG_MD_TYPE)
25
26 #include "mbedtls/hmac_drbg.h"
27
28 #elif defined(MBEDTLS_CTR_DRBG_C)
29
30 #include "mbedtls/ctr_drbg.h"
31
32 #elif defined(MBEDTLS_HMAC_DRBG_C)
33
34 #include "mbedtls/hmac_drbg.h"
35 #if defined(MBEDTLS_MD_CAN_SHA512) && defined(MBEDTLS_MD_CAN_SHA256)
36 #include <limits.h>
37 #if SIZE_MAX > 0xffffffff
38 /* Looks like a 64-bit system, so prefer SHA-512. */
39 #define MBEDTLS_PSA_HMAC_DRBG_MD_TYPE MBEDTLS_MD_SHA512
40 #else
41 /* Looks like a 32-bit system, so prefer SHA-256. */
42 #define MBEDTLS_PSA_HMAC_DRBG_MD_TYPE MBEDTLS_MD_SHA256
43 #endif
44 #elif defined(MBEDTLS_MD_CAN_SHA512)
45 #define MBEDTLS_PSA_HMAC_DRBG_MD_TYPE MBEDTLS_MD_SHA512
46 #elif defined(MBEDTLS_MD_CAN_SHA256)
47 #define MBEDTLS_PSA_HMAC_DRBG_MD_TYPE MBEDTLS_MD_SHA256
48 #else
49 #error "No hash algorithm available for HMAC_DBRG."
50 #endif
51
52 #else /* !MBEDTLS_PSA_HMAC_DRBG_MD_TYPE && !MBEDTLS_CTR_DRBG_C && !MBEDTLS_HMAC_DRBG_C*/
53
54 #error "No DRBG module available for the psa_crypto module."
55
56 #endif /* !MBEDTLS_PSA_HMAC_DRBG_MD_TYPE && !MBEDTLS_CTR_DRBG_C && !MBEDTLS_HMAC_DRBG_C*/
57
58 #if defined(MBEDTLS_CTR_DRBG_C)
59 #include "mbedtls/ctr_drbg.h"
60 #elif defined(MBEDTLS_HMAC_DRBG_C)
61 #include "mbedtls/hmac_drbg.h"
62 #endif /* !MBEDTLS_CTR_DRBG_C && !MBEDTLS_HMAC_DRBG_C */
63
64 /* The maximum number of bytes that mbedtls_psa_get_random() is expected to return. */
65 #if defined(MBEDTLS_CTR_DRBG_C)
66 #define MBEDTLS_PSA_RANDOM_MAX_REQUEST MBEDTLS_CTR_DRBG_MAX_REQUEST
67 #elif defined(MBEDTLS_HMAC_DRBG_C)
68 #define MBEDTLS_PSA_RANDOM_MAX_REQUEST MBEDTLS_HMAC_DRBG_MAX_REQUEST
69 #endif
70
71 #if defined(MBEDTLS_CTR_DRBG_C)
72 typedef mbedtls_ctr_drbg_context mbedtls_psa_drbg_context_t;
73 #elif defined(MBEDTLS_HMAC_DRBG_C)
74 typedef mbedtls_hmac_drbg_context mbedtls_psa_drbg_context_t;
75 #endif /* !MBEDTLS_CTR_DRBG_C && !MBEDTLS_HMAC_DRBG_C */
76
77 typedef struct {
78 void (* entropy_init)(mbedtls_entropy_context *ctx);
79 void (* entropy_free)(mbedtls_entropy_context *ctx);
80 mbedtls_entropy_context entropy;
81 mbedtls_psa_drbg_context_t drbg;
82 } mbedtls_psa_random_context_t;
83
84 /** Initialize the PSA DRBG.
85 *
86 * \param p_rng Pointer to the Mbed TLS DRBG state.
87 */
mbedtls_psa_drbg_init(mbedtls_psa_drbg_context_t * p_rng)88 static inline void mbedtls_psa_drbg_init(mbedtls_psa_drbg_context_t *p_rng)
89 {
90 #if defined(MBEDTLS_CTR_DRBG_C)
91 mbedtls_ctr_drbg_init(p_rng);
92 #elif defined(MBEDTLS_HMAC_DRBG_C)
93 mbedtls_hmac_drbg_init(p_rng);
94 #endif
95 }
96
97 /** Deinitialize the PSA DRBG.
98 *
99 * \param p_rng Pointer to the Mbed TLS DRBG state.
100 */
mbedtls_psa_drbg_free(mbedtls_psa_drbg_context_t * p_rng)101 static inline void mbedtls_psa_drbg_free(mbedtls_psa_drbg_context_t *p_rng)
102 {
103 #if defined(MBEDTLS_CTR_DRBG_C)
104 mbedtls_ctr_drbg_free(p_rng);
105 #elif defined(MBEDTLS_HMAC_DRBG_C)
106 mbedtls_hmac_drbg_free(p_rng);
107 #endif
108 }
109
110 /** Seed the PSA DRBG.
111 *
112 * \param entropy An entropy context to read the seed from.
113 * \param custom The personalization string.
114 * This can be \c NULL, in which case the personalization
115 * string is empty regardless of the value of \p len.
116 * \param len The length of the personalization string.
117 *
118 * \return \c 0 on success.
119 * \return An Mbed TLS error code (\c MBEDTLS_ERR_xxx) on failure.
120 */
mbedtls_psa_drbg_seed(mbedtls_psa_drbg_context_t * drbg_ctx,mbedtls_entropy_context * entropy,const unsigned char * custom,size_t len)121 static inline int mbedtls_psa_drbg_seed(mbedtls_psa_drbg_context_t *drbg_ctx,
122 mbedtls_entropy_context *entropy,
123 const unsigned char *custom, size_t len)
124 {
125 #if defined(MBEDTLS_CTR_DRBG_C)
126 return mbedtls_ctr_drbg_seed(drbg_ctx, mbedtls_entropy_func, entropy, custom, len);
127 #elif defined(MBEDTLS_HMAC_DRBG_C)
128 const mbedtls_md_info_t *md_info = mbedtls_md_info_from_type(MBEDTLS_PSA_HMAC_DRBG_MD_TYPE);
129 return mbedtls_hmac_drbg_seed(drbg_ctx, md_info, mbedtls_entropy_func, entropy, custom, len);
130 #endif
131 }
132
133 #endif /* MBEDTLS_PSA_CRYPTO_EXTERNAL_RNG */
134
135 #endif /* PSA_CRYPTO_RANDOM_IMPL_H */
136
