mirror of
https://github.com/Mbed-TLS/mbedtls.git
synced 2026-04-03 19:16:06 +02:00
a863415205
Let applications configure prediction resistance at runtime. Prediction resistance is always considered disabled when there is no actual entropy source, only a nonvolatile seed. Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
184 lines
6.0 KiB
C
184 lines
6.0 KiB
C
/** \file psa_crypto_random_impl.h
|
|
*
|
|
* \brief PSA crypto random generator implementation abstraction.
|
|
*/
|
|
/*
|
|
* Copyright The Mbed TLS Contributors
|
|
* SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later
|
|
*/
|
|
|
|
#ifndef PSA_CRYPTO_RANDOM_IMPL_H
|
|
#define PSA_CRYPTO_RANDOM_IMPL_H
|
|
|
|
#include "psa_util_internal.h"
|
|
|
|
#if defined(MBEDTLS_PSA_CRYPTO_EXTERNAL_RNG)
|
|
|
|
typedef mbedtls_psa_external_random_context_t mbedtls_psa_random_context_t;
|
|
|
|
#else /* MBEDTLS_PSA_CRYPTO_EXTERNAL_RNG */
|
|
|
|
#include "mbedtls/entropy.h"
|
|
|
|
/* Choose a DRBG based on configuration and availability */
|
|
#if defined(MBEDTLS_CTR_DRBG_C)
|
|
|
|
#include "mbedtls/ctr_drbg.h"
|
|
#undef MBEDTLS_PSA_HMAC_DRBG_MD_TYPE
|
|
|
|
#elif defined(MBEDTLS_HMAC_DRBG_C)
|
|
|
|
#include "mbedtls/hmac_drbg.h"
|
|
#if defined(MBEDTLS_MD_CAN_SHA512) && defined(MBEDTLS_MD_CAN_SHA256)
|
|
#include <limits.h>
|
|
#if SIZE_MAX > 0xffffffff
|
|
/* Looks like a 64-bit system, so prefer SHA-512. */
|
|
#define MBEDTLS_PSA_HMAC_DRBG_MD_TYPE MBEDTLS_MD_SHA512
|
|
#else
|
|
/* Looks like a 32-bit system, so prefer SHA-256. */
|
|
#define MBEDTLS_PSA_HMAC_DRBG_MD_TYPE MBEDTLS_MD_SHA256
|
|
#endif
|
|
#elif defined(MBEDTLS_MD_CAN_SHA512)
|
|
#define MBEDTLS_PSA_HMAC_DRBG_MD_TYPE MBEDTLS_MD_SHA512
|
|
#elif defined(MBEDTLS_MD_CAN_SHA256)
|
|
#define MBEDTLS_PSA_HMAC_DRBG_MD_TYPE MBEDTLS_MD_SHA256
|
|
#else
|
|
#error "No hash algorithm available for HMAC_DBRG."
|
|
#endif
|
|
|
|
#else /* !MBEDTLS_CTR_DRBG_C && !MBEDTLS_HMAC_DRBG_C*/
|
|
|
|
#error "No DRBG module available for the psa_crypto module."
|
|
|
|
#endif /* !MBEDTLS_CTR_DRBG_C && !MBEDTLS_HMAC_DRBG_C*/
|
|
|
|
/* The maximum number of bytes that mbedtls_psa_get_random() is expected to return. */
|
|
#if defined(MBEDTLS_CTR_DRBG_C)
|
|
#define MBEDTLS_PSA_RANDOM_MAX_REQUEST MBEDTLS_CTR_DRBG_MAX_REQUEST
|
|
#elif defined(MBEDTLS_HMAC_DRBG_C)
|
|
#define MBEDTLS_PSA_RANDOM_MAX_REQUEST MBEDTLS_HMAC_DRBG_MAX_REQUEST
|
|
#endif
|
|
|
|
#if defined(MBEDTLS_CTR_DRBG_C)
|
|
typedef mbedtls_ctr_drbg_context mbedtls_psa_drbg_context_t;
|
|
#elif defined(MBEDTLS_HMAC_DRBG_C)
|
|
typedef mbedtls_hmac_drbg_context mbedtls_psa_drbg_context_t;
|
|
#endif /* !MBEDTLS_CTR_DRBG_C && !MBEDTLS_HMAC_DRBG_C */
|
|
|
|
typedef struct {
|
|
void (* entropy_init)(mbedtls_entropy_context *ctx);
|
|
void (* entropy_free)(mbedtls_entropy_context *ctx);
|
|
mbedtls_entropy_context entropy;
|
|
mbedtls_psa_drbg_context_t drbg;
|
|
} mbedtls_psa_random_context_t;
|
|
|
|
/** Initialize the PSA DRBG.
|
|
*
|
|
* \param p_rng Pointer to the Mbed TLS DRBG state.
|
|
*/
|
|
static inline void mbedtls_psa_drbg_init(mbedtls_psa_drbg_context_t *p_rng)
|
|
{
|
|
#if defined(MBEDTLS_CTR_DRBG_C)
|
|
mbedtls_ctr_drbg_init(p_rng);
|
|
#elif defined(MBEDTLS_HMAC_DRBG_C)
|
|
mbedtls_hmac_drbg_init(p_rng);
|
|
#endif
|
|
}
|
|
|
|
/** Deinitialize the PSA DRBG.
|
|
*
|
|
* \param p_rng Pointer to the Mbed TLS DRBG state.
|
|
*/
|
|
static inline void mbedtls_psa_drbg_free(mbedtls_psa_drbg_context_t *p_rng)
|
|
{
|
|
#if defined(MBEDTLS_CTR_DRBG_C)
|
|
mbedtls_ctr_drbg_free(p_rng);
|
|
#elif defined(MBEDTLS_HMAC_DRBG_C)
|
|
mbedtls_hmac_drbg_free(p_rng);
|
|
#endif
|
|
}
|
|
|
|
/** Seed the PSA DRBG.
|
|
*
|
|
* \param drbg_ctx The DRBG context to seed.
|
|
* It must be initialized but not active.
|
|
* \param entropy An entropy context to read the seed from.
|
|
* \param custom The personalization string.
|
|
* This can be \c NULL, in which case the personalization
|
|
* string is empty regardless of the value of \p len.
|
|
* \param len The length of the personalization string.
|
|
*
|
|
* \return \c 0 on success.
|
|
* \return An Mbed TLS error code (\c MBEDTLS_ERR_xxx) on failure.
|
|
*/
|
|
static inline int mbedtls_psa_drbg_seed(mbedtls_psa_drbg_context_t *drbg_ctx,
|
|
mbedtls_entropy_context *entropy,
|
|
const unsigned char *custom, size_t len)
|
|
{
|
|
#if defined(MBEDTLS_CTR_DRBG_C)
|
|
return mbedtls_ctr_drbg_seed(drbg_ctx, mbedtls_entropy_func, entropy, custom, len);
|
|
#elif defined(MBEDTLS_HMAC_DRBG_C)
|
|
const mbedtls_md_info_t *md_info = mbedtls_md_info_from_type(MBEDTLS_PSA_HMAC_DRBG_MD_TYPE);
|
|
return mbedtls_hmac_drbg_seed(drbg_ctx, md_info, mbedtls_entropy_func, entropy, custom, len);
|
|
#endif
|
|
}
|
|
|
|
/** Reseed the PSA DRBG.
|
|
*
|
|
* \param drbg_ctx The DRBG context to reseed.
|
|
* It must be active.
|
|
* \param additional Additional data to inject.
|
|
* \param len The length of \p additional in bytes.
|
|
* This can be 0 to simply reseed from the entropy source.
|
|
*
|
|
* \return \c 0 on success.
|
|
* \return An Mbed TLS error code (\c MBEDTLS_ERR_xxx) on failure.
|
|
*/
|
|
static inline int mbedtls_psa_drbg_reseed(mbedtls_psa_drbg_context_t *drbg_ctx,
|
|
const unsigned char *additional,
|
|
size_t len)
|
|
{
|
|
#if defined(MBEDTLS_CTR_DRBG_C)
|
|
return mbedtls_ctr_drbg_reseed(drbg_ctx, additional, len);
|
|
#elif defined(MBEDTLS_HMAC_DRBG_C)
|
|
return mbedtls_hmac_drbg_reseed(drbg_ctx, additional, len);
|
|
#endif
|
|
}
|
|
|
|
/** Deplete the PSA DRBG, i.e. cause it to reseed the next time it is used.
|
|
*
|
|
* \note This function is not thread-safe.
|
|
*
|
|
* \param drbg_ctx The DRBG context to deplete.
|
|
* It must be active.
|
|
*/
|
|
static inline void mbedtls_psa_drbg_deplete(mbedtls_psa_drbg_context_t *drbg_ctx)
|
|
{
|
|
drbg_ctx->reseed_counter = drbg_ctx->reseed_interval;
|
|
}
|
|
|
|
#if MBEDTLS_ENTROPY_TRUE_SOURCES > 0
|
|
/** Set prediction resistance in the PSA DRBG.
|
|
*
|
|
* \note This function is not thread-safe.
|
|
*
|
|
* \param drbg_ctx The DRBG context to reconfigure.
|
|
* It must be active.
|
|
* \param enabled \c 1 to enable, or \c 0 to disable.
|
|
*/
|
|
static inline void mbedtls_psa_drbg_set_prediction_resistance(
|
|
mbedtls_psa_drbg_context_t *drbg_ctx,
|
|
unsigned enabled)
|
|
{
|
|
#if defined(MBEDTLS_CTR_DRBG_C)
|
|
mbedtls_ctr_drbg_set_prediction_resistance(drbg_ctx, enabled);
|
|
#elif defined(MBEDTLS_HMAC_DRBG_C)
|
|
mbedtls_hmac_drbg_set_prediction_resistance(drbg_ctx, enabled);
|
|
#endif
|
|
}
|
|
#endif /* MBEDTLS_ENTROPY_TRUE_SOURCES > 0 */
|
|
|
|
#endif /* MBEDTLS_PSA_CRYPTO_EXTERNAL_RNG */
|
|
|
|
#endif /* PSA_CRYPTO_RANDOM_IMPL_H */
|