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Merge pull request #4110 from gilles-peskine-arm/psa-external-random-in-mbedtls

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Expose the PSA RNG in mbedtls
This commit is contained in:
Dave Rodgman
2021-02-22 14:47:29 +00:00
committed by GitHub
parent bd21b18a1f 277a3a6609
commit d6ee36ed04
13 changed files with 597 additions and 87 deletions
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4
library/entropy_poll.c
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@ -220,13 +220,13 @@ int mbedtls_null_entropy_poll( void *data,
{
((void) data);
((void) output);
*olen = 0;
*olen = 0;
if( len < sizeof(unsigned char) )
return( 0 );
output[0] = 0;
*olen = sizeof(unsigned char);
return( 0 );
}
#endif

58
library/psa_crypto_random_impl.h
View File

@ -1,6 +1,14 @@
/** \file psa_crypto_random_impl.h
*
* \brief PSA crypto random generator implementation abstraction.
*
* The definitions here need to be consistent with the declarations
* in include/mbedtls/psa_util.h. This file contains some redundant
* declarations to increase the chance that a compiler will detect
* inconsistencies if one file is changed without updating the other,
* but not all potential inconsistencies can be enforced, so make sure
* to check the public declarations and contracts in
* include/mbedtls/psa_util.h if you modify this file.
*/
/*
* Copyright The Mbed TLS Contributors
@ -22,6 +30,8 @@
#ifndef PSA_CRYPTO_RANDOM_IMPL_H
#define PSA_CRYPTO_RANDOM_IMPL_H
#include <mbedtls/psa_util.h>
#if defined(MBEDTLS_PSA_CRYPTO_EXTERNAL_RNG)
#include <string.h>
@ -75,14 +85,6 @@ int mbedtls_psa_get_random( void *p_rng,
#include "mbedtls/entropy.h"
/** The type of the PSA DRBG context.
*/
#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
/** Initialize the PSA DRBG.
*
* \param p_rng Pointer to the Mbed TLS DRBG state.
@ -122,33 +124,18 @@ typedef struct
mbedtls_psa_drbg_context_t drbg;
} mbedtls_psa_random_context_t;
/* The type of an Mbed TLS random generator function. This should be
* part of the public API instead of repeating the type everywhere.
* For the time being, declare it here. Declaring a type is necessary
* to define mbedtls_psa_get_random as a variable of a function pointer
* type without incurring the wrath of check-names.sh. */
typedef int mbedtls_f_rng_t( void *p_rng, unsigned char *output, size_t output_size );
/** Return random data.
*
* This function is suitable as the \p f_rng parameter to Mbed TLS functions
* that require a random generator. Use #MBEDTLS_PSA_RANDOM_STATE to
* obtain the \p p_rng parameter.
*
* \param p_rng The DRBG context. This must be
* #MBEDTLS_PSA_RANDOM_STATE.
* \param output The buffer to fill.
* \param output_len The length of the buffer in bytes.
* It must be at most #MBEDTLS_PSA_RANDOM_MAX_REQUEST.
*
* \retval \c 0 on success.
* \return \c MBEDTLS_ERR_xxx_DRBG_xxx or
* \c MBEDTLS_ERR_PLATFORM_xxx on failure.
/* Defined in include/mbedtls/psa_util.h so that it's visible to
* application code. The declaration here is redundant, but included
* as a safety net to make it more likely that a future change that
* accidentally causes the implementation to diverge from the interface
* will be noticed. */
/* Do not include the declaration under MSVC because it doesn't accept it
* ("error C2370: 'mbedtls_psa_get_random' : redefinition; different storage class").
* Observed with Visual Studio 2013. A known bug apparently:
* https://stackoverflow.com/questions/8146541/duplicate-external-static-declarations-not-allowed-in-visual-studio
*/
#if defined(MBEDTLS_CTR_DRBG_C)
static mbedtls_f_rng_t *const mbedtls_psa_get_random = mbedtls_ctr_drbg_random;
#elif defined(MBEDTLS_HMAC_DRBG_C)
static mbedtls_f_rng_t *const mbedtls_psa_get_random = mbedtls_hmac_drbg_random;
#if !defined(_MSC_VER)
static mbedtls_f_rng_t *const mbedtls_psa_get_random;
#endif
/** The maximum number of bytes that mbedtls_psa_get_random() is expected to
@ -167,6 +154,9 @@ static mbedtls_f_rng_t *const mbedtls_psa_get_random = mbedtls_hmac_drbg_random;
*/
/* psa_crypto.c sets this variable to a pointer to the DRBG state in the
* global PSA crypto state. */
/* The type `mbedtls_psa_drbg_context_t` is defined in
* include/mbedtls/psa_util.h so that `mbedtls_psa_random_state` can be
* declared there and be visible to application code. */
extern mbedtls_psa_drbg_context_t *const mbedtls_psa_random_state;
/** A pointer to the PSA DRBG state.