/** * \file entropy.h * * \brief Entropy accumulator implementation */ /* * Copyright The Mbed TLS Contributors * SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later */ #ifndef MBEDTLS_ENTROPY_H #define MBEDTLS_ENTROPY_H #include "mbedtls/private_access.h" #include "mbedtls/build_info.h" #include #include "md.h" #if defined(MBEDTLS_MD_CAN_SHA512) && !defined(MBEDTLS_ENTROPY_FORCE_SHA256) #define MBEDTLS_ENTROPY_SHA512_ACCUMULATOR #define MBEDTLS_ENTROPY_MD MBEDTLS_MD_SHA512 #define MBEDTLS_ENTROPY_BLOCK_SIZE 64 /**< Block size of entropy accumulator (SHA-512) */ #else #if defined(MBEDTLS_MD_CAN_SHA256) #define MBEDTLS_ENTROPY_SHA256_ACCUMULATOR #define MBEDTLS_ENTROPY_MD MBEDTLS_MD_SHA256 #define MBEDTLS_ENTROPY_BLOCK_SIZE 32 /**< Block size of entropy accumulator (SHA-256) */ #endif #endif #if defined(MBEDTLS_THREADING_C) #include "mbedtls/threading.h" #endif /** Critical entropy source failure. */ #define MBEDTLS_ERR_ENTROPY_SOURCE_FAILED -0x003C /** No more sources can be added. */ #define MBEDTLS_ERR_ENTROPY_MAX_SOURCES -0x003E /** No sources have been added to poll. */ #define MBEDTLS_ERR_ENTROPY_NO_SOURCES_DEFINED -0x0040 /** No strong sources have been added to poll. */ #define MBEDTLS_ERR_ENTROPY_NO_STRONG_SOURCE -0x003D /** Read/write error in file. */ #define MBEDTLS_ERR_ENTROPY_FILE_IO_ERROR -0x003F /** * \name SECTION: Module settings * * The configuration options you can set for this module are in this section. * Either change them in mbedtls_config.h or define them on the compiler command line. * \{ */ #if !defined(MBEDTLS_ENTROPY_MAX_SOURCES) #define MBEDTLS_ENTROPY_MAX_SOURCES 20 /**< Maximum number of sources supported */ #endif #if !defined(MBEDTLS_ENTROPY_MAX_GATHER) #define MBEDTLS_ENTROPY_MAX_GATHER 128 /**< Maximum amount requested from entropy sources */ #endif /** \} name SECTION: Module settings */ #define MBEDTLS_ENTROPY_MAX_SEED_SIZE 1024 /**< Maximum size of seed we read from seed file */ #define MBEDTLS_ENTROPY_SOURCE_MANUAL MBEDTLS_ENTROPY_MAX_SOURCES #define MBEDTLS_ENTROPY_SOURCE_STRONG 1 /**< Entropy source is strong */ #define MBEDTLS_ENTROPY_SOURCE_WEAK 0 /**< Entropy source is weak */ #ifdef __cplusplus extern "C" { #endif /** * \brief Entropy poll callback pointer * * \param data Callback-specific data pointer * \param output Data to fill * \param len Maximum size to provide * \param olen The actual amount of bytes put into the buffer (Can be 0) * * \return 0 if no critical failures occurred, * MBEDTLS_ERR_ENTROPY_SOURCE_FAILED otherwise */ typedef int (*mbedtls_entropy_f_source_ptr)(void *data, unsigned char *output, size_t len, size_t *olen); /** * \brief Entropy source state */ typedef struct mbedtls_entropy_source_state { mbedtls_entropy_f_source_ptr MBEDTLS_PRIVATE(f_source); /**< The entropy source callback */ void *MBEDTLS_PRIVATE(p_source); /**< The callback data pointer */ size_t MBEDTLS_PRIVATE(size); /**< Amount received in bytes */ size_t MBEDTLS_PRIVATE(threshold); /**< Minimum bytes required before release */ int MBEDTLS_PRIVATE(strong); /**< Is the source strong? */ } mbedtls_entropy_source_state; /** * \brief Entropy context structure */ typedef struct mbedtls_entropy_context { mbedtls_md_context_t MBEDTLS_PRIVATE(accumulator); int MBEDTLS_PRIVATE(accumulator_started); /* 0 after init. * 1 after the first update. * -1 after free. */ int MBEDTLS_PRIVATE(source_count); /* Number of entries used in source. */ mbedtls_entropy_source_state MBEDTLS_PRIVATE(source)[MBEDTLS_ENTROPY_MAX_SOURCES]; #if defined(MBEDTLS_THREADING_C) mbedtls_threading_mutex_t MBEDTLS_PRIVATE(mutex); /*!< mutex */ #endif #if defined(MBEDTLS_ENTROPY_NV_SEED) int MBEDTLS_PRIVATE(initial_entropy_run); #endif } mbedtls_entropy_context; #if !defined(MBEDTLS_NO_PLATFORM_ENTROPY) /** * \brief Platform-specific entropy poll callback */ int mbedtls_platform_entropy_poll(void *data, unsigned char *output, size_t len, size_t *olen); #endif /** * \brief Initialize the context * * \param ctx Entropy context to initialize */ void mbedtls_entropy_init(mbedtls_entropy_context *ctx); /** * \brief Free the data in the context * * \param ctx Entropy context to free */ void mbedtls_entropy_free(mbedtls_entropy_context *ctx); /** * \brief Adds an entropy source to poll * (Thread-safe if MBEDTLS_THREADING_C is enabled) * * \param ctx Entropy context * \param f_source Entropy function * \param p_source Function data * \param threshold Minimum required from source before entropy is released * ( with mbedtls_entropy_func() ) (in bytes) * \param strong MBEDTLS_ENTROPY_SOURCE_STRONG or * MBEDTLS_ENTROPY_SOURCE_WEAK. * At least one strong source needs to be added. * Weaker sources (such as the cycle counter) can be used as * a complement. * * \return 0 if successful or MBEDTLS_ERR_ENTROPY_MAX_SOURCES */ int mbedtls_entropy_add_source(mbedtls_entropy_context *ctx, mbedtls_entropy_f_source_ptr f_source, void *p_source, size_t threshold, int strong); /** * \brief Trigger an extra gather poll for the accumulator * (Thread-safe if MBEDTLS_THREADING_C is enabled) * * \param ctx Entropy context * * \return 0 if successful, or MBEDTLS_ERR_ENTROPY_SOURCE_FAILED */ int mbedtls_entropy_gather(mbedtls_entropy_context *ctx); /** * \brief Retrieve entropy from the accumulator * (Maximum length: MBEDTLS_ENTROPY_BLOCK_SIZE) * (Thread-safe if MBEDTLS_THREADING_C is enabled) * * \param data Entropy context * \param output Buffer to fill * \param len Number of bytes desired, must be at most MBEDTLS_ENTROPY_BLOCK_SIZE * * \return 0 if successful, or MBEDTLS_ERR_ENTROPY_SOURCE_FAILED */ int mbedtls_entropy_func(void *data, unsigned char *output, size_t len); /** * \brief Add data to the accumulator manually * (Thread-safe if MBEDTLS_THREADING_C is enabled) * * \param ctx Entropy context * \param data Data to add * \param len Length of data * * \return 0 if successful */ int mbedtls_entropy_update_manual(mbedtls_entropy_context *ctx, const unsigned char *data, size_t len); #if defined(MBEDTLS_ENTROPY_NV_SEED) /** * \brief Trigger an update of the seed file in NV by using the * current entropy pool. * * \param ctx Entropy context * * \return 0 if successful */ int mbedtls_entropy_update_nv_seed(mbedtls_entropy_context *ctx); #endif /* MBEDTLS_ENTROPY_NV_SEED */ #if defined(MBEDTLS_FS_IO) /** * \brief Write a seed file * * \param ctx Entropy context * \param path Name of the file * * \return 0 if successful, * MBEDTLS_ERR_ENTROPY_FILE_IO_ERROR on file error, or * MBEDTLS_ERR_ENTROPY_SOURCE_FAILED */ int mbedtls_entropy_write_seed_file(mbedtls_entropy_context *ctx, const char *path); /** * \brief Read and update a seed file. Seed is added to this * instance. No more than MBEDTLS_ENTROPY_MAX_SEED_SIZE bytes are * read from the seed file. The rest is ignored. * * \param ctx Entropy context * \param path Name of the file * * \return 0 if successful, * MBEDTLS_ERR_ENTROPY_FILE_IO_ERROR on file error, * MBEDTLS_ERR_ENTROPY_SOURCE_FAILED */ int mbedtls_entropy_update_seed_file(mbedtls_entropy_context *ctx, const char *path); #endif /* MBEDTLS_FS_IO */ #if defined(MBEDTLS_SELF_TEST) /** * \brief Checkup routine * * This module self-test also calls the entropy self-test, * mbedtls_entropy_source_self_test(); * * \return 0 if successful, or 1 if a test failed */ int mbedtls_entropy_self_test(int verbose); #if defined(MBEDTLS_ENTROPY_HARDWARE_ALT) /** * \brief Checkup routine * * Verifies the integrity of the hardware entropy source * provided by the function 'mbedtls_hardware_poll()'. * * Note this is the only hardware entropy source that is known * at link time, and other entropy sources configured * dynamically at runtime by the function * mbedtls_entropy_add_source() will not be tested. * * \return 0 if successful, or 1 if a test failed */ int mbedtls_entropy_source_self_test(int verbose); #endif /* MBEDTLS_ENTROPY_HARDWARE_ALT */ #endif /* MBEDTLS_SELF_TEST */ #ifdef __cplusplus } #endif #endif /* entropy.h */