/** * \file entropy.h * * \brief Entropy accumulator implementation * * Copyright (C) 2006-2013, Brainspark B.V. * * This file is part of PolarSSL (http://www.polarssl.org) * Lead Maintainer: Paul Bakker * * All rights reserved. * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License along * with this program; if not, write to the Free Software Foundation, Inc., * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. */ #ifndef POLARSSL_ENTROPY_H #define POLARSSL_ENTROPY_H #include #include "config.h" #if defined(POLARSSL_SHA512_C) && !defined(POLARSSL_ENTROPY_FORCE_SHA256) #include "sha512.h" #define POLARSSL_ENTROPY_SHA512_ACCUMULATOR #else #if defined(POLARSSL_SHA256_C) #define POLARSSL_ENTROPY_SHA256_ACCUMULATOR #include "sha256.h" #endif #endif #if defined(POLARSSL_THREADING_C) #include "threading.h" #endif #if defined(POLARSSL_HAVEGE_C) #include "havege.h" #endif #define POLARSSL_ERR_ENTROPY_SOURCE_FAILED -0x003C /**< Critical entropy source failure. */ #define POLARSSL_ERR_ENTROPY_MAX_SOURCES -0x003E /**< No more sources can be added. */ #define POLARSSL_ERR_ENTROPY_NO_SOURCES_DEFINED -0x0040 /**< No sources have been added to poll. */ #define POLARSSL_ERR_ENTROPY_FILE_IO_ERROR -0x0058 /**< Read/write error in file. */ /** * \name SECTION: Module settings * * The configuration options you can set for this module are in this section. * Either change them in config.h or define them on the compiler command line. * \{ */ #if !defined(ENTROPY_MAX_SOURCES) #define ENTROPY_MAX_SOURCES 20 /**< Maximum number of sources supported */ #endif #if !defined(ENTROPY_MAX_GATHER) #define ENTROPY_MAX_GATHER 128 /**< Maximum amount requested from entropy sources */ #endif /* \} name SECTION: Module settings */ #if defined(POLARSSL_ENTROPY_SHA512_ACCUMULATOR) #define ENTROPY_BLOCK_SIZE 64 /**< Block size of entropy accumulator (SHA-512) */ #else #define ENTROPY_BLOCK_SIZE 32 /**< Block size of entropy accumulator (SHA-256) */ #endif #define ENTROPY_MAX_SEED_SIZE 1024 /**< Maximum size of seed we read from seed file */ #define ENTROPY_SOURCE_MANUAL ENTROPY_MAX_SOURCES #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, * POLARSSL_ERR_ENTROPY_SOURCE_FAILED otherwise */ typedef int (*f_source_ptr)(void *data, unsigned char *output, size_t len, size_t *olen); /** * \brief Entropy source state */ typedef struct { f_source_ptr f_source; /**< The entropy source callback */ void * p_source; /**< The callback data pointer */ size_t size; /**< Amount received */ size_t threshold; /**< Minimum level required before release */ } source_state; /** * \brief Entropy context structure */ typedef struct { #if defined(POLARSSL_ENTROPY_SHA512_ACCUMULATOR) sha512_context accumulator; #else sha256_context accumulator; #endif int source_count; source_state source[ENTROPY_MAX_SOURCES]; #if defined(POLARSSL_HAVEGE_C) havege_state havege_data; #endif #if defined(POLARSSL_THREADING_C) threading_mutex_t mutex; /*!< mutex */ #endif } entropy_context; /** * \brief Initialize the context * * \param ctx Entropy context to initialize */ void entropy_init( entropy_context *ctx ); /** * \brief Free the data in the context * * \param ctx Entropy context to free */ void entropy_free( entropy_context *ctx ); /** * \brief Adds an entropy source to poll * (Thread-safe if POLARSSL_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 entropy_func() ) * * \return 0 if successful or POLARSSL_ERR_ENTROPY_MAX_SOURCES */ int entropy_add_source( entropy_context *ctx, f_source_ptr f_source, void *p_source, size_t threshold ); /** * \brief Trigger an extra gather poll for the accumulator * (Thread-safe if POLARSSL_THREADING_C is enabled) * * \param ctx Entropy context * * \return 0 if successful, or POLARSSL_ERR_ENTROPY_SOURCE_FAILED */ int entropy_gather( entropy_context *ctx ); /** * \brief Retrieve entropy from the accumulator (Max ENTROPY_BLOCK_SIZE) * (Thread-safe if POLARSSL_THREADING_C is enabled) * * \param data Entropy context * \param output Buffer to fill * \param len Length of buffer * * \return 0 if successful, or POLARSSL_ERR_ENTROPY_SOURCE_FAILED */ int entropy_func( void *data, unsigned char *output, size_t len ); /** * \brief Add data to the accumulator manually * (Thread-safe if POLARSSL_THREADING_C is enabled) * * \param ctx Entropy context * \param data Data to add * \param len Length of data * * \return 0 if successful */ int entropy_update_manual( entropy_context *ctx, const unsigned char *data, size_t len ); #if defined(POLARSSL_FS_IO) /** * \brief Write a seed file * * \param ctx Entropy context * \param path Name of the file * * \return 0 if successful, * POLARSSL_ERR_ENTROPY_FILE_IO_ERROR on file error, or * POLARSSL_ERR_ENTROPY_SOURCE_FAILED */ int entropy_write_seed_file( entropy_context *ctx, const char *path ); /** * \brief Read and update a seed file. Seed is added to this * instance. No more than 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, * POLARSSL_ERR_ENTROPY_FILE_IO_ERROR on file error, * POLARSSL_ERR_ENTROPY_SOURCE_FAILED */ int entropy_update_seed_file( entropy_context *ctx, const char *path ); #endif #ifdef __cplusplus } #endif #endif /* entropy.h */