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Diffstat (limited to 'include/mbedtls/entropy.h')
| -rw-r--r-- | include/mbedtls/entropy.h | 273 |
1 files changed, 273 insertions, 0 deletions
diff --git a/include/mbedtls/entropy.h b/include/mbedtls/entropy.h new file mode 100644 index 0000000..20fd687 --- /dev/null +++ b/include/mbedtls/entropy.h @@ -0,0 +1,273 @@ +/** + * \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 <stddef.h> + +#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 */ |