| 1 | /** |
| 2 | * \file entropy.h |
| 3 | * |
| 4 | * \brief Entropy accumulator implementation |
| 5 | */ |
| 6 | /* |
| 7 | * Copyright (C) 2006-2016, ARM Limited, All Rights Reserved |
| 8 | * SPDX-License-Identifier: GPL-2.0 |
| 9 | * |
| 10 | * This program is free software; you can redistribute it and/or modify |
| 11 | * it under the terms of the GNU General Public License as published by |
| 12 | * the Free Software Foundation; either version 2 of the License, or |
| 13 | * (at your option) any later version. |
| 14 | * |
| 15 | * This program is distributed in the hope that it will be useful, |
| 16 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 17 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 18 | * GNU General Public License for more details. |
| 19 | * |
| 20 | * You should have received a copy of the GNU General Public License along |
| 21 | * with this program; if not, write to the Free Software Foundation, Inc., |
| 22 | * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. |
| 23 | * |
| 24 | * This file is part of mbed TLS (https://tls.mbed.org) |
| 25 | */ |
| 26 | #ifndef MBEDTLS_ENTROPY_H |
| 27 | #define MBEDTLS_ENTROPY_H |
| 28 | |
| 29 | #if !defined(MBEDTLS_CONFIG_FILE) |
| 30 | #include "config.h" |
| 31 | #else |
| 32 | #include MBEDTLS_CONFIG_FILE |
| 33 | #endif |
| 34 | |
| 35 | #include <stddef.h> |
| 36 | |
| 37 | #if defined(MBEDTLS_SHA512_C) && !defined(MBEDTLS_ENTROPY_FORCE_SHA256) |
| 38 | #include "sha512.h" |
| 39 | #define MBEDTLS_ENTROPY_SHA512_ACCUMULATOR |
| 40 | #else |
| 41 | #if defined(MBEDTLS_SHA256_C) |
| 42 | #define MBEDTLS_ENTROPY_SHA256_ACCUMULATOR |
| 43 | #include "sha256.h" |
| 44 | #endif |
| 45 | #endif |
| 46 | |
| 47 | #if defined(MBEDTLS_THREADING_C) |
| 48 | #include "threading.h" |
| 49 | #endif |
| 50 | |
| 51 | #if defined(MBEDTLS_HAVEGE_C) |
| 52 | #include "havege.h" |
| 53 | #endif |
| 54 | |
| 55 | #define MBEDTLS_ERR_ENTROPY_SOURCE_FAILED -0x003C /**< Critical entropy source failure. */ |
| 56 | #define MBEDTLS_ERR_ENTROPY_MAX_SOURCES -0x003E /**< No more sources can be added. */ |
| 57 | #define MBEDTLS_ERR_ENTROPY_NO_SOURCES_DEFINED -0x0040 /**< No sources have been added to poll. */ |
| 58 | #define MBEDTLS_ERR_ENTROPY_NO_STRONG_SOURCE -0x003D /**< No strong sources have been added to poll. */ |
| 59 | #define MBEDTLS_ERR_ENTROPY_FILE_IO_ERROR -0x003F /**< Read/write error in file. */ |
| 60 | |
| 61 | /** |
| 62 | * \name SECTION: Module settings |
| 63 | * |
| 64 | * The configuration options you can set for this module are in this section. |
| 65 | * Either change them in config.h or define them on the compiler command line. |
| 66 | * \{ |
| 67 | */ |
| 68 | |
| 69 | #if !defined(MBEDTLS_ENTROPY_MAX_SOURCES) |
| 70 | #define MBEDTLS_ENTROPY_MAX_SOURCES 20 /**< Maximum number of sources supported */ |
| 71 | #endif |
| 72 | |
| 73 | #if !defined(MBEDTLS_ENTROPY_MAX_GATHER) |
| 74 | #define MBEDTLS_ENTROPY_MAX_GATHER 128 /**< Maximum amount requested from entropy sources */ |
| 75 | #endif |
| 76 | |
| 77 | /* \} name SECTION: Module settings */ |
| 78 | |
| 79 | #if defined(MBEDTLS_ENTROPY_SHA512_ACCUMULATOR) |
| 80 | #define MBEDTLS_ENTROPY_BLOCK_SIZE 64 /**< Block size of entropy accumulator (SHA-512) */ |
| 81 | #else |
| 82 | #define MBEDTLS_ENTROPY_BLOCK_SIZE 32 /**< Block size of entropy accumulator (SHA-256) */ |
| 83 | #endif |
| 84 | |
| 85 | #define MBEDTLS_ENTROPY_MAX_SEED_SIZE 1024 /**< Maximum size of seed we read from seed file */ |
| 86 | #define MBEDTLS_ENTROPY_SOURCE_MANUAL MBEDTLS_ENTROPY_MAX_SOURCES |
| 87 | |
| 88 | #define MBEDTLS_ENTROPY_SOURCE_STRONG 1 /**< Entropy source is strong */ |
| 89 | #define MBEDTLS_ENTROPY_SOURCE_WEAK 0 /**< Entropy source is weak */ |
| 90 | |
| 91 | #ifdef __cplusplus |
| 92 | extern "C" { |
| 93 | #endif |
| 94 | |
| 95 | /** |
| 96 | * \brief Entropy poll callback pointer |
| 97 | * |
| 98 | * \param data Callback-specific data pointer |
| 99 | * \param output Data to fill |
| 100 | * \param len Maximum size to provide |
| 101 | * \param olen The actual amount of bytes put into the buffer (Can be 0) |
| 102 | * |
| 103 | * \return 0 if no critical failures occurred, |
| 104 | * MBEDTLS_ERR_ENTROPY_SOURCE_FAILED otherwise |
| 105 | */ |
| 106 | typedef int (*mbedtls_entropy_f_source_ptr)(void *data, unsigned char *output, size_t len, |
| 107 | size_t *olen); |
| 108 | |
| 109 | /** |
| 110 | * \brief Entropy source state |
| 111 | */ |
| 112 | typedef struct mbedtls_entropy_source_state |
| 113 | { |
| 114 | mbedtls_entropy_f_source_ptr f_source; /**< The entropy source callback */ |
| 115 | void * p_source; /**< The callback data pointer */ |
| 116 | size_t size; /**< Amount received in bytes */ |
| 117 | size_t threshold; /**< Minimum bytes required before release */ |
| 118 | int strong; /**< Is the source strong? */ |
| 119 | } |
| 120 | mbedtls_entropy_source_state; |
| 121 | |
| 122 | /** |
| 123 | * \brief Entropy context structure |
| 124 | */ |
| 125 | typedef struct mbedtls_entropy_context |
| 126 | { |
| 127 | int accumulator_started; |
| 128 | #if defined(MBEDTLS_ENTROPY_SHA512_ACCUMULATOR) |
| 129 | mbedtls_sha512_context accumulator; |
| 130 | #else |
| 131 | mbedtls_sha256_context accumulator; |
| 132 | #endif |
| 133 | int source_count; |
| 134 | mbedtls_entropy_source_state source[MBEDTLS_ENTROPY_MAX_SOURCES]; |
| 135 | #if defined(MBEDTLS_HAVEGE_C) |
| 136 | mbedtls_havege_state havege_data; |
| 137 | #endif |
| 138 | #if defined(MBEDTLS_THREADING_C) |
| 139 | mbedtls_threading_mutex_t mutex; /*!< mutex */ |
| 140 | #endif |
| 141 | #if defined(MBEDTLS_ENTROPY_NV_SEED) |
| 142 | int initial_entropy_run; |
| 143 | #endif |
| 144 | } |
| 145 | mbedtls_entropy_context; |
| 146 | |
| 147 | /** |
| 148 | * \brief Initialize the context |
| 149 | * |
| 150 | * \param ctx Entropy context to initialize |
| 151 | */ |
| 152 | void mbedtls_entropy_init( mbedtls_entropy_context *ctx ); |
| 153 | |
| 154 | /** |
| 155 | * \brief Free the data in the context |
| 156 | * |
| 157 | * \param ctx Entropy context to free |
| 158 | */ |
| 159 | void mbedtls_entropy_free( mbedtls_entropy_context *ctx ); |
| 160 | |
| 161 | /** |
| 162 | * \brief Adds an entropy source to poll |
| 163 | * (Thread-safe if MBEDTLS_THREADING_C is enabled) |
| 164 | * |
| 165 | * \param ctx Entropy context |
| 166 | * \param f_source Entropy function |
| 167 | * \param p_source Function data |
| 168 | * \param threshold Minimum required from source before entropy is released |
| 169 | * ( with mbedtls_entropy_func() ) (in bytes) |
| 170 | * \param strong MBEDTLS_ENTROPY_SOURCE_STRONG or |
| 171 | * MBEDTLS_ENTROPY_SOURCE_WEAK. |
| 172 | * At least one strong source needs to be added. |
| 173 | * Weaker sources (such as the cycle counter) can be used as |
| 174 | * a complement. |
| 175 | * |
| 176 | * \return 0 if successful or MBEDTLS_ERR_ENTROPY_MAX_SOURCES |
| 177 | */ |
| 178 | int mbedtls_entropy_add_source( mbedtls_entropy_context *ctx, |
| 179 | mbedtls_entropy_f_source_ptr f_source, void *p_source, |
| 180 | size_t threshold, int strong ); |
| 181 | |
| 182 | /** |
| 183 | * \brief Trigger an extra gather poll for the accumulator |
| 184 | * (Thread-safe if MBEDTLS_THREADING_C is enabled) |
| 185 | * |
| 186 | * \param ctx Entropy context |
| 187 | * |
| 188 | * \return 0 if successful, or MBEDTLS_ERR_ENTROPY_SOURCE_FAILED |
| 189 | */ |
| 190 | int mbedtls_entropy_gather( mbedtls_entropy_context *ctx ); |
| 191 | |
| 192 | /** |
| 193 | * \brief Retrieve entropy from the accumulator |
| 194 | * (Maximum length: MBEDTLS_ENTROPY_BLOCK_SIZE) |
| 195 | * (Thread-safe if MBEDTLS_THREADING_C is enabled) |
| 196 | * |
| 197 | * \param data Entropy context |
| 198 | * \param output Buffer to fill |
| 199 | * \param len Number of bytes desired, must be at most MBEDTLS_ENTROPY_BLOCK_SIZE |
| 200 | * |
| 201 | * \return 0 if successful, or MBEDTLS_ERR_ENTROPY_SOURCE_FAILED |
| 202 | */ |
| 203 | int mbedtls_entropy_func( void *data, unsigned char *output, size_t len ); |
| 204 | |
| 205 | /** |
| 206 | * \brief Add data to the accumulator manually |
| 207 | * (Thread-safe if MBEDTLS_THREADING_C is enabled) |
| 208 | * |
| 209 | * \param ctx Entropy context |
| 210 | * \param data Data to add |
| 211 | * \param len Length of data |
| 212 | * |
| 213 | * \return 0 if successful |
| 214 | */ |
| 215 | int mbedtls_entropy_update_manual( mbedtls_entropy_context *ctx, |
| 216 | const unsigned char *data, size_t len ); |
| 217 | |
| 218 | #if defined(MBEDTLS_ENTROPY_NV_SEED) |
| 219 | /** |
| 220 | * \brief Trigger an update of the seed file in NV by using the |
| 221 | * current entropy pool. |
| 222 | * |
| 223 | * \param ctx Entropy context |
| 224 | * |
| 225 | * \return 0 if successful |
| 226 | */ |
| 227 | int mbedtls_entropy_update_nv_seed( mbedtls_entropy_context *ctx ); |
| 228 | #endif /* MBEDTLS_ENTROPY_NV_SEED */ |
| 229 | |
| 230 | #if defined(MBEDTLS_FS_IO) |
| 231 | /** |
| 232 | * \brief Write a seed file |
| 233 | * |
| 234 | * \param ctx Entropy context |
| 235 | * \param path Name of the file |
| 236 | * |
| 237 | * \return 0 if successful, |
| 238 | * MBEDTLS_ERR_ENTROPY_FILE_IO_ERROR on file error, or |
| 239 | * MBEDTLS_ERR_ENTROPY_SOURCE_FAILED |
| 240 | */ |
| 241 | int mbedtls_entropy_write_seed_file( mbedtls_entropy_context *ctx, const char *path ); |
| 242 | |
| 243 | /** |
| 244 | * \brief Read and update a seed file. Seed is added to this |
| 245 | * instance. No more than MBEDTLS_ENTROPY_MAX_SEED_SIZE bytes are |
| 246 | * read from the seed file. The rest is ignored. |
| 247 | * |
| 248 | * \param ctx Entropy context |
| 249 | * \param path Name of the file |
| 250 | * |
| 251 | * \return 0 if successful, |
| 252 | * MBEDTLS_ERR_ENTROPY_FILE_IO_ERROR on file error, |
| 253 | * MBEDTLS_ERR_ENTROPY_SOURCE_FAILED |
| 254 | */ |
| 255 | int mbedtls_entropy_update_seed_file( mbedtls_entropy_context *ctx, const char *path ); |
| 256 | #endif /* MBEDTLS_FS_IO */ |
| 257 | |
| 258 | #if defined(MBEDTLS_SELF_TEST) |
| 259 | /** |
| 260 | * \brief Checkup routine |
| 261 | * |
| 262 | * This module self-test also calls the entropy self-test, |
| 263 | * mbedtls_entropy_source_self_test(); |
| 264 | * |
| 265 | * \return 0 if successful, or 1 if a test failed |
| 266 | */ |
| 267 | int mbedtls_entropy_self_test( int verbose ); |
| 268 | |
| 269 | #if defined(MBEDTLS_ENTROPY_HARDWARE_ALT) |
| 270 | /** |
| 271 | * \brief Checkup routine |
| 272 | * |
| 273 | * Verifies the integrity of the hardware entropy source |
| 274 | * provided by the function 'mbedtls_hardware_poll()'. |
| 275 | * |
| 276 | * Note this is the only hardware entropy source that is known |
| 277 | * at link time, and other entropy sources configured |
| 278 | * dynamically at runtime by the function |
| 279 | * mbedtls_entropy_add_source() will not be tested. |
| 280 | * |
| 281 | * \return 0 if successful, or 1 if a test failed |
| 282 | */ |
| 283 | int mbedtls_entropy_source_self_test( int verbose ); |
| 284 | #endif /* MBEDTLS_ENTROPY_HARDWARE_ALT */ |
| 285 | #endif /* MBEDTLS_SELF_TEST */ |
| 286 | |
| 287 | #ifdef __cplusplus |
| 288 | } |
| 289 | #endif |
| 290 | |
| 291 | #endif /* entropy.h */ |