| 1 | /* |
| 2 | * Entropy accumulator implementation |
| 3 | * |
| 4 | * Copyright (C) 2006-2016, ARM Limited, All Rights Reserved |
| 5 | * SPDX-License-Identifier: GPL-2.0 |
| 6 | * |
| 7 | * This program is free software; you can redistribute it and/or modify |
| 8 | * it under the terms of the GNU General Public License as published by |
| 9 | * the Free Software Foundation; either version 2 of the License, or |
| 10 | * (at your option) any later version. |
| 11 | * |
| 12 | * This program is distributed in the hope that it will be useful, |
| 13 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 14 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 15 | * GNU General Public License for more details. |
| 16 | * |
| 17 | * You should have received a copy of the GNU General Public License along |
| 18 | * with this program; if not, write to the Free Software Foundation, Inc., |
| 19 | * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. |
| 20 | * |
| 21 | * This file is part of mbed TLS (https://tls.mbed.org) |
| 22 | */ |
| 23 | |
| 24 | #if !defined(MBEDTLS_CONFIG_FILE) |
| 25 | #include "mbedtls/config.h" |
| 26 | #else |
| 27 | #include MBEDTLS_CONFIG_FILE |
| 28 | #endif |
| 29 | |
| 30 | #if defined(MBEDTLS_ENTROPY_C) |
| 31 | |
| 32 | #if defined(MBEDTLS_TEST_NULL_ENTROPY) |
| 33 | #warning "**** WARNING! MBEDTLS_TEST_NULL_ENTROPY defined! " |
| 34 | #warning "**** THIS BUILD HAS NO DEFINED ENTROPY SOURCES " |
| 35 | #warning "**** THIS BUILD IS *NOT* SUITABLE FOR PRODUCTION USE " |
| 36 | #endif |
| 37 | |
| 38 | #include "mbedtls/entropy.h" |
| 39 | #include "mbedtls/entropy_poll.h" |
| 40 | #include "mbedtls/platform_util.h" |
| 41 | |
| 42 | #include <string.h> |
| 43 | |
| 44 | #if defined(MBEDTLS_FS_IO) |
| 45 | #include <stdio.h> |
| 46 | #endif |
| 47 | |
| 48 | #if defined(MBEDTLS_ENTROPY_NV_SEED) |
| 49 | #include "mbedtls/platform.h" |
| 50 | #endif |
| 51 | |
| 52 | #if defined(MBEDTLS_SELF_TEST) |
| 53 | #if defined(MBEDTLS_PLATFORM_C) |
| 54 | #include "mbedtls/platform.h" |
| 55 | #else |
| 56 | #include <stdio.h> |
| 57 | #define mbedtls_printf printf |
| 58 | #endif /* MBEDTLS_PLATFORM_C */ |
| 59 | #endif /* MBEDTLS_SELF_TEST */ |
| 60 | |
| 61 | #if defined(MBEDTLS_HAVEGE_C) |
| 62 | #include "mbedtls/havege.h" |
| 63 | #endif |
| 64 | |
| 65 | #define ENTROPY_MAX_LOOP 256 /**< Maximum amount to loop before error */ |
| 66 | |
| 67 | void mbedtls_entropy_init( mbedtls_entropy_context *ctx ) |
| 68 | { |
| 69 | ctx->source_count = 0; |
| 70 | memset( ctx->source, 0, sizeof( ctx->source ) ); |
| 71 | |
| 72 | #if defined(MBEDTLS_THREADING_C) |
| 73 | mbedtls_mutex_init( &ctx->mutex ); |
| 74 | #endif |
| 75 | |
| 76 | ctx->accumulator_started = 0; |
| 77 | #if defined(MBEDTLS_ENTROPY_SHA512_ACCUMULATOR) |
| 78 | mbedtls_sha512_init( &ctx->accumulator ); |
| 79 | #else |
| 80 | mbedtls_sha256_init( &ctx->accumulator ); |
| 81 | #endif |
| 82 | #if defined(MBEDTLS_HAVEGE_C) |
| 83 | mbedtls_havege_init( &ctx->havege_data ); |
| 84 | #endif |
| 85 | |
| 86 | /* Reminder: Update ENTROPY_HAVE_STRONG in the test files |
| 87 | * when adding more strong entropy sources here. */ |
| 88 | |
| 89 | #if defined(MBEDTLS_TEST_NULL_ENTROPY) |
| 90 | mbedtls_entropy_add_source( ctx, mbedtls_null_entropy_poll, NULL, |
| 91 | 1, MBEDTLS_ENTROPY_SOURCE_STRONG ); |
| 92 | #endif |
| 93 | |
| 94 | #if !defined(MBEDTLS_NO_DEFAULT_ENTROPY_SOURCES) |
| 95 | #if !defined(MBEDTLS_NO_PLATFORM_ENTROPY) |
| 96 | mbedtls_entropy_add_source( ctx, mbedtls_platform_entropy_poll, NULL, |
| 97 | MBEDTLS_ENTROPY_MIN_PLATFORM, |
| 98 | MBEDTLS_ENTROPY_SOURCE_STRONG ); |
| 99 | #endif |
| 100 | #if defined(MBEDTLS_TIMING_C) |
| 101 | mbedtls_entropy_add_source( ctx, mbedtls_hardclock_poll, NULL, |
| 102 | MBEDTLS_ENTROPY_MIN_HARDCLOCK, |
| 103 | MBEDTLS_ENTROPY_SOURCE_WEAK ); |
| 104 | #endif |
| 105 | #if defined(MBEDTLS_HAVEGE_C) |
| 106 | mbedtls_entropy_add_source( ctx, mbedtls_havege_poll, &ctx->havege_data, |
| 107 | MBEDTLS_ENTROPY_MIN_HAVEGE, |
| 108 | MBEDTLS_ENTROPY_SOURCE_STRONG ); |
| 109 | #endif |
| 110 | #if defined(MBEDTLS_ENTROPY_HARDWARE_ALT) |
| 111 | mbedtls_entropy_add_source( ctx, mbedtls_hardware_poll, NULL, |
| 112 | MBEDTLS_ENTROPY_MIN_HARDWARE, |
| 113 | MBEDTLS_ENTROPY_SOURCE_STRONG ); |
| 114 | #endif |
| 115 | #if defined(MBEDTLS_ENTROPY_NV_SEED) |
| 116 | mbedtls_entropy_add_source( ctx, mbedtls_nv_seed_poll, NULL, |
| 117 | MBEDTLS_ENTROPY_BLOCK_SIZE, |
| 118 | MBEDTLS_ENTROPY_SOURCE_STRONG ); |
| 119 | ctx->initial_entropy_run = 0; |
| 120 | #endif |
| 121 | #endif /* MBEDTLS_NO_DEFAULT_ENTROPY_SOURCES */ |
| 122 | } |
| 123 | |
| 124 | void mbedtls_entropy_free( mbedtls_entropy_context *ctx ) |
| 125 | { |
| 126 | #if defined(MBEDTLS_HAVEGE_C) |
| 127 | mbedtls_havege_free( &ctx->havege_data ); |
| 128 | #endif |
| 129 | #if defined(MBEDTLS_THREADING_C) |
| 130 | mbedtls_mutex_free( &ctx->mutex ); |
| 131 | #endif |
| 132 | #if defined(MBEDTLS_ENTROPY_SHA512_ACCUMULATOR) |
| 133 | mbedtls_sha512_free( &ctx->accumulator ); |
| 134 | #else |
| 135 | mbedtls_sha256_free( &ctx->accumulator ); |
| 136 | #endif |
| 137 | #if defined(MBEDTLS_ENTROPY_NV_SEED) |
| 138 | ctx->initial_entropy_run = 0; |
| 139 | #endif |
| 140 | ctx->source_count = 0; |
| 141 | mbedtls_platform_zeroize( ctx->source, sizeof( ctx->source ) ); |
| 142 | ctx->accumulator_started = 0; |
| 143 | } |
| 144 | |
| 145 | int mbedtls_entropy_add_source( mbedtls_entropy_context *ctx, |
| 146 | mbedtls_entropy_f_source_ptr f_source, void *p_source, |
| 147 | size_t threshold, int strong ) |
| 148 | { |
| 149 | int idx, ret = 0; |
| 150 | |
| 151 | #if defined(MBEDTLS_THREADING_C) |
| 152 | if( ( ret = mbedtls_mutex_lock( &ctx->mutex ) ) != 0 ) |
| 153 | return( ret ); |
| 154 | #endif |
| 155 | |
| 156 | idx = ctx->source_count; |
| 157 | if( idx >= MBEDTLS_ENTROPY_MAX_SOURCES ) |
| 158 | { |
| 159 | ret = MBEDTLS_ERR_ENTROPY_MAX_SOURCES; |
| 160 | goto exit; |
| 161 | } |
| 162 | |
| 163 | ctx->source[idx].f_source = f_source; |
| 164 | ctx->source[idx].p_source = p_source; |
| 165 | ctx->source[idx].threshold = threshold; |
| 166 | ctx->source[idx].strong = strong; |
| 167 | |
| 168 | ctx->source_count++; |
| 169 | |
| 170 | exit: |
| 171 | #if defined(MBEDTLS_THREADING_C) |
| 172 | if( mbedtls_mutex_unlock( &ctx->mutex ) != 0 ) |
| 173 | return( MBEDTLS_ERR_THREADING_MUTEX_ERROR ); |
| 174 | #endif |
| 175 | |
| 176 | return( ret ); |
| 177 | } |
| 178 | |
| 179 | /* |
| 180 | * Entropy accumulator update |
| 181 | */ |
| 182 | static int entropy_update( mbedtls_entropy_context *ctx, unsigned char source_id, |
| 183 | const unsigned char *data, size_t len ) |
| 184 | { |
| 185 | unsigned char header[2]; |
| 186 | unsigned char tmp[MBEDTLS_ENTROPY_BLOCK_SIZE]; |
| 187 | size_t use_len = len; |
| 188 | const unsigned char *p = data; |
| 189 | int ret = 0; |
| 190 | |
| 191 | if( use_len > MBEDTLS_ENTROPY_BLOCK_SIZE ) |
| 192 | { |
| 193 | #if defined(MBEDTLS_ENTROPY_SHA512_ACCUMULATOR) |
| 194 | if( ( ret = mbedtls_sha512_ret( data, len, tmp, 0 ) ) != 0 ) |
| 195 | goto cleanup; |
| 196 | #else |
| 197 | if( ( ret = mbedtls_sha256_ret( data, len, tmp, 0 ) ) != 0 ) |
| 198 | goto cleanup; |
| 199 | #endif |
| 200 | p = tmp; |
| 201 | use_len = MBEDTLS_ENTROPY_BLOCK_SIZE; |
| 202 | } |
| 203 | |
| 204 | header[0] = source_id; |
| 205 | header[1] = use_len & 0xFF; |
| 206 | |
| 207 | /* |
| 208 | * Start the accumulator if this has not already happened. Note that |
| 209 | * it is sufficient to start the accumulator here only because all calls to |
| 210 | * gather entropy eventually execute this code. |
| 211 | */ |
| 212 | #if defined(MBEDTLS_ENTROPY_SHA512_ACCUMULATOR) |
| 213 | if( ctx->accumulator_started == 0 && |
| 214 | ( ret = mbedtls_sha512_starts_ret( &ctx->accumulator, 0 ) ) != 0 ) |
| 215 | goto cleanup; |
| 216 | else |
| 217 | ctx->accumulator_started = 1; |
| 218 | if( ( ret = mbedtls_sha512_update_ret( &ctx->accumulator, header, 2 ) ) != 0 ) |
| 219 | goto cleanup; |
| 220 | ret = mbedtls_sha512_update_ret( &ctx->accumulator, p, use_len ); |
| 221 | #else |
| 222 | if( ctx->accumulator_started == 0 && |
| 223 | ( ret = mbedtls_sha256_starts_ret( &ctx->accumulator, 0 ) ) != 0 ) |
| 224 | goto cleanup; |
| 225 | else |
| 226 | ctx->accumulator_started = 1; |
| 227 | if( ( ret = mbedtls_sha256_update_ret( &ctx->accumulator, header, 2 ) ) != 0 ) |
| 228 | goto cleanup; |
| 229 | ret = mbedtls_sha256_update_ret( &ctx->accumulator, p, use_len ); |
| 230 | #endif |
| 231 | |
| 232 | cleanup: |
| 233 | mbedtls_platform_zeroize( tmp, sizeof( tmp ) ); |
| 234 | |
| 235 | return( ret ); |
| 236 | } |
| 237 | |
| 238 | int mbedtls_entropy_update_manual( mbedtls_entropy_context *ctx, |
| 239 | const unsigned char *data, size_t len ) |
| 240 | { |
| 241 | int ret; |
| 242 | |
| 243 | #if defined(MBEDTLS_THREADING_C) |
| 244 | if( ( ret = mbedtls_mutex_lock( &ctx->mutex ) ) != 0 ) |
| 245 | return( ret ); |
| 246 | #endif |
| 247 | |
| 248 | ret = entropy_update( ctx, MBEDTLS_ENTROPY_SOURCE_MANUAL, data, len ); |
| 249 | |
| 250 | #if defined(MBEDTLS_THREADING_C) |
| 251 | if( mbedtls_mutex_unlock( &ctx->mutex ) != 0 ) |
| 252 | return( MBEDTLS_ERR_THREADING_MUTEX_ERROR ); |
| 253 | #endif |
| 254 | |
| 255 | return( ret ); |
| 256 | } |
| 257 | |
| 258 | /* |
| 259 | * Run through the different sources to add entropy to our accumulator |
| 260 | */ |
| 261 | static int entropy_gather_internal( mbedtls_entropy_context *ctx ) |
| 262 | { |
| 263 | int ret, i, have_one_strong = 0; |
| 264 | unsigned char buf[MBEDTLS_ENTROPY_MAX_GATHER]; |
| 265 | size_t olen; |
| 266 | |
| 267 | if( ctx->source_count == 0 ) |
| 268 | return( MBEDTLS_ERR_ENTROPY_NO_SOURCES_DEFINED ); |
| 269 | |
| 270 | /* |
| 271 | * Run through our entropy sources |
| 272 | */ |
| 273 | for( i = 0; i < ctx->source_count; i++ ) |
| 274 | { |
| 275 | if( ctx->source[i].strong == MBEDTLS_ENTROPY_SOURCE_STRONG ) |
| 276 | have_one_strong = 1; |
| 277 | |
| 278 | olen = 0; |
| 279 | if( ( ret = ctx->source[i].f_source( ctx->source[i].p_source, |
| 280 | buf, MBEDTLS_ENTROPY_MAX_GATHER, &olen ) ) != 0 ) |
| 281 | { |
| 282 | goto cleanup; |
| 283 | } |
| 284 | |
| 285 | /* |
| 286 | * Add if we actually gathered something |
| 287 | */ |
| 288 | if( olen > 0 ) |
| 289 | { |
| 290 | if( ( ret = entropy_update( ctx, (unsigned char) i, |
| 291 | buf, olen ) ) != 0 ) |
| 292 | return( ret ); |
| 293 | ctx->source[i].size += olen; |
| 294 | } |
| 295 | } |
| 296 | |
| 297 | if( have_one_strong == 0 ) |
| 298 | ret = MBEDTLS_ERR_ENTROPY_NO_STRONG_SOURCE; |
| 299 | |
| 300 | cleanup: |
| 301 | mbedtls_platform_zeroize( buf, sizeof( buf ) ); |
| 302 | |
| 303 | return( ret ); |
| 304 | } |
| 305 | |
| 306 | /* |
| 307 | * Thread-safe wrapper for entropy_gather_internal() |
| 308 | */ |
| 309 | int mbedtls_entropy_gather( mbedtls_entropy_context *ctx ) |
| 310 | { |
| 311 | int ret; |
| 312 | |
| 313 | #if defined(MBEDTLS_THREADING_C) |
| 314 | if( ( ret = mbedtls_mutex_lock( &ctx->mutex ) ) != 0 ) |
| 315 | return( ret ); |
| 316 | #endif |
| 317 | |
| 318 | ret = entropy_gather_internal( ctx ); |
| 319 | |
| 320 | #if defined(MBEDTLS_THREADING_C) |
| 321 | if( mbedtls_mutex_unlock( &ctx->mutex ) != 0 ) |
| 322 | return( MBEDTLS_ERR_THREADING_MUTEX_ERROR ); |
| 323 | #endif |
| 324 | |
| 325 | return( ret ); |
| 326 | } |
| 327 | |
| 328 | int mbedtls_entropy_func( void *data, unsigned char *output, size_t len ) |
| 329 | { |
| 330 | int ret, count = 0, i, done; |
| 331 | mbedtls_entropy_context *ctx = (mbedtls_entropy_context *) data; |
| 332 | unsigned char buf[MBEDTLS_ENTROPY_BLOCK_SIZE]; |
| 333 | |
| 334 | if( len > MBEDTLS_ENTROPY_BLOCK_SIZE ) |
| 335 | return( MBEDTLS_ERR_ENTROPY_SOURCE_FAILED ); |
| 336 | |
| 337 | #if defined(MBEDTLS_ENTROPY_NV_SEED) |
| 338 | /* Update the NV entropy seed before generating any entropy for outside |
| 339 | * use. |
| 340 | */ |
| 341 | if( ctx->initial_entropy_run == 0 ) |
| 342 | { |
| 343 | ctx->initial_entropy_run = 1; |
| 344 | if( ( ret = mbedtls_entropy_update_nv_seed( ctx ) ) != 0 ) |
| 345 | return( ret ); |
| 346 | } |
| 347 | #endif |
| 348 | |
| 349 | #if defined(MBEDTLS_THREADING_C) |
| 350 | if( ( ret = mbedtls_mutex_lock( &ctx->mutex ) ) != 0 ) |
| 351 | return( ret ); |
| 352 | #endif |
| 353 | |
| 354 | /* |
| 355 | * Always gather extra entropy before a call |
| 356 | */ |
| 357 | do |
| 358 | { |
| 359 | if( count++ > ENTROPY_MAX_LOOP ) |
| 360 | { |
| 361 | ret = MBEDTLS_ERR_ENTROPY_SOURCE_FAILED; |
| 362 | goto exit; |
| 363 | } |
| 364 | |
| 365 | if( ( ret = entropy_gather_internal( ctx ) ) != 0 ) |
| 366 | goto exit; |
| 367 | |
| 368 | done = 1; |
| 369 | for( i = 0; i < ctx->source_count; i++ ) |
| 370 | if( ctx->source[i].size < ctx->source[i].threshold ) |
| 371 | done = 0; |
| 372 | } |
| 373 | while( ! done ); |
| 374 | |
| 375 | memset( buf, 0, MBEDTLS_ENTROPY_BLOCK_SIZE ); |
| 376 | |
| 377 | #if defined(MBEDTLS_ENTROPY_SHA512_ACCUMULATOR) |
| 378 | /* |
| 379 | * Note that at this stage it is assumed that the accumulator was started |
| 380 | * in a previous call to entropy_update(). If this is not guaranteed, the |
| 381 | * code below will fail. |
| 382 | */ |
| 383 | if( ( ret = mbedtls_sha512_finish_ret( &ctx->accumulator, buf ) ) != 0 ) |
| 384 | goto exit; |
| 385 | |
| 386 | /* |
| 387 | * Reset accumulator and counters and recycle existing entropy |
| 388 | */ |
| 389 | mbedtls_sha512_free( &ctx->accumulator ); |
| 390 | mbedtls_sha512_init( &ctx->accumulator ); |
| 391 | if( ( ret = mbedtls_sha512_starts_ret( &ctx->accumulator, 0 ) ) != 0 ) |
| 392 | goto exit; |
| 393 | if( ( ret = mbedtls_sha512_update_ret( &ctx->accumulator, buf, |
| 394 | MBEDTLS_ENTROPY_BLOCK_SIZE ) ) != 0 ) |
| 395 | goto exit; |
| 396 | |
| 397 | /* |
| 398 | * Perform second SHA-512 on entropy |
| 399 | */ |
| 400 | if( ( ret = mbedtls_sha512_ret( buf, MBEDTLS_ENTROPY_BLOCK_SIZE, |
| 401 | buf, 0 ) ) != 0 ) |
| 402 | goto exit; |
| 403 | #else /* MBEDTLS_ENTROPY_SHA512_ACCUMULATOR */ |
| 404 | if( ( ret = mbedtls_sha256_finish_ret( &ctx->accumulator, buf ) ) != 0 ) |
| 405 | goto exit; |
| 406 | |
| 407 | /* |
| 408 | * Reset accumulator and counters and recycle existing entropy |
| 409 | */ |
| 410 | mbedtls_sha256_free( &ctx->accumulator ); |
| 411 | mbedtls_sha256_init( &ctx->accumulator ); |
| 412 | if( ( ret = mbedtls_sha256_starts_ret( &ctx->accumulator, 0 ) ) != 0 ) |
| 413 | goto exit; |
| 414 | if( ( ret = mbedtls_sha256_update_ret( &ctx->accumulator, buf, |
| 415 | MBEDTLS_ENTROPY_BLOCK_SIZE ) ) != 0 ) |
| 416 | goto exit; |
| 417 | |
| 418 | /* |
| 419 | * Perform second SHA-256 on entropy |
| 420 | */ |
| 421 | if( ( ret = mbedtls_sha256_ret( buf, MBEDTLS_ENTROPY_BLOCK_SIZE, |
| 422 | buf, 0 ) ) != 0 ) |
| 423 | goto exit; |
| 424 | #endif /* MBEDTLS_ENTROPY_SHA512_ACCUMULATOR */ |
| 425 | |
| 426 | for( i = 0; i < ctx->source_count; i++ ) |
| 427 | ctx->source[i].size = 0; |
| 428 | |
| 429 | memcpy( output, buf, len ); |
| 430 | |
| 431 | ret = 0; |
| 432 | |
| 433 | exit: |
| 434 | mbedtls_platform_zeroize( buf, sizeof( buf ) ); |
| 435 | |
| 436 | #if defined(MBEDTLS_THREADING_C) |
| 437 | if( mbedtls_mutex_unlock( &ctx->mutex ) != 0 ) |
| 438 | return( MBEDTLS_ERR_THREADING_MUTEX_ERROR ); |
| 439 | #endif |
| 440 | |
| 441 | return( ret ); |
| 442 | } |
| 443 | |
| 444 | #if defined(MBEDTLS_ENTROPY_NV_SEED) |
| 445 | int mbedtls_entropy_update_nv_seed( mbedtls_entropy_context *ctx ) |
| 446 | { |
| 447 | int ret = MBEDTLS_ERR_ENTROPY_FILE_IO_ERROR; |
| 448 | unsigned char buf[MBEDTLS_ENTROPY_BLOCK_SIZE]; |
| 449 | |
| 450 | /* Read new seed and write it to NV */ |
| 451 | if( ( ret = mbedtls_entropy_func( ctx, buf, MBEDTLS_ENTROPY_BLOCK_SIZE ) ) != 0 ) |
| 452 | return( ret ); |
| 453 | |
| 454 | if( mbedtls_nv_seed_write( buf, MBEDTLS_ENTROPY_BLOCK_SIZE ) < 0 ) |
| 455 | return( MBEDTLS_ERR_ENTROPY_FILE_IO_ERROR ); |
| 456 | |
| 457 | /* Manually update the remaining stream with a separator value to diverge */ |
| 458 | memset( buf, 0, MBEDTLS_ENTROPY_BLOCK_SIZE ); |
| 459 | ret = mbedtls_entropy_update_manual( ctx, buf, MBEDTLS_ENTROPY_BLOCK_SIZE ); |
| 460 | |
| 461 | return( ret ); |
| 462 | } |
| 463 | #endif /* MBEDTLS_ENTROPY_NV_SEED */ |
| 464 | |
| 465 | #if defined(MBEDTLS_FS_IO) |
| 466 | int mbedtls_entropy_write_seed_file( mbedtls_entropy_context *ctx, const char *path ) |
| 467 | { |
| 468 | int ret = MBEDTLS_ERR_ENTROPY_FILE_IO_ERROR; |
| 469 | FILE *f; |
| 470 | unsigned char buf[MBEDTLS_ENTROPY_BLOCK_SIZE]; |
| 471 | |
| 472 | if( ( f = fopen( path, "wb" ) ) == NULL ) |
| 473 | return( MBEDTLS_ERR_ENTROPY_FILE_IO_ERROR ); |
| 474 | |
| 475 | if( ( ret = mbedtls_entropy_func( ctx, buf, MBEDTLS_ENTROPY_BLOCK_SIZE ) ) != 0 ) |
| 476 | goto exit; |
| 477 | |
| 478 | if( fwrite( buf, 1, MBEDTLS_ENTROPY_BLOCK_SIZE, f ) != MBEDTLS_ENTROPY_BLOCK_SIZE ) |
| 479 | { |
| 480 | ret = MBEDTLS_ERR_ENTROPY_FILE_IO_ERROR; |
| 481 | goto exit; |
| 482 | } |
| 483 | |
| 484 | ret = 0; |
| 485 | |
| 486 | exit: |
| 487 | mbedtls_platform_zeroize( buf, sizeof( buf ) ); |
| 488 | |
| 489 | fclose( f ); |
| 490 | return( ret ); |
| 491 | } |
| 492 | |
| 493 | int mbedtls_entropy_update_seed_file( mbedtls_entropy_context *ctx, const char *path ) |
| 494 | { |
| 495 | int ret = 0; |
| 496 | FILE *f; |
| 497 | size_t n; |
| 498 | unsigned char buf[ MBEDTLS_ENTROPY_MAX_SEED_SIZE ]; |
| 499 | |
| 500 | if( ( f = fopen( path, "rb" ) ) == NULL ) |
| 501 | return( MBEDTLS_ERR_ENTROPY_FILE_IO_ERROR ); |
| 502 | |
| 503 | fseek( f, 0, SEEK_END ); |
| 504 | n = (size_t) ftell( f ); |
| 505 | fseek( f, 0, SEEK_SET ); |
| 506 | |
| 507 | if( n > MBEDTLS_ENTROPY_MAX_SEED_SIZE ) |
| 508 | n = MBEDTLS_ENTROPY_MAX_SEED_SIZE; |
| 509 | |
| 510 | if( fread( buf, 1, n, f ) != n ) |
| 511 | ret = MBEDTLS_ERR_ENTROPY_FILE_IO_ERROR; |
| 512 | else |
| 513 | ret = mbedtls_entropy_update_manual( ctx, buf, n ); |
| 514 | |
| 515 | fclose( f ); |
| 516 | |
| 517 | mbedtls_platform_zeroize( buf, sizeof( buf ) ); |
| 518 | |
| 519 | if( ret != 0 ) |
| 520 | return( ret ); |
| 521 | |
| 522 | return( mbedtls_entropy_write_seed_file( ctx, path ) ); |
| 523 | } |
| 524 | #endif /* MBEDTLS_FS_IO */ |
| 525 | |
| 526 | #if defined(MBEDTLS_SELF_TEST) |
| 527 | #if !defined(MBEDTLS_TEST_NULL_ENTROPY) |
| 528 | /* |
| 529 | * Dummy source function |
| 530 | */ |
| 531 | static int entropy_dummy_source( void *data, unsigned char *output, |
| 532 | size_t len, size_t *olen ) |
| 533 | { |
| 534 | ((void) data); |
| 535 | |
| 536 | memset( output, 0x2a, len ); |
| 537 | *olen = len; |
| 538 | |
| 539 | return( 0 ); |
| 540 | } |
| 541 | #endif /* !MBEDTLS_TEST_NULL_ENTROPY */ |
| 542 | |
| 543 | #if defined(MBEDTLS_ENTROPY_HARDWARE_ALT) |
| 544 | |
| 545 | static int mbedtls_entropy_source_self_test_gather( unsigned char *buf, size_t buf_len ) |
| 546 | { |
| 547 | int ret = 0; |
| 548 | size_t entropy_len = 0; |
| 549 | size_t olen = 0; |
| 550 | size_t attempts = buf_len; |
| 551 | |
| 552 | while( attempts > 0 && entropy_len < buf_len ) |
| 553 | { |
| 554 | if( ( ret = mbedtls_hardware_poll( NULL, buf + entropy_len, |
| 555 | buf_len - entropy_len, &olen ) ) != 0 ) |
| 556 | return( ret ); |
| 557 | |
| 558 | entropy_len += olen; |
| 559 | attempts--; |
| 560 | } |
| 561 | |
| 562 | if( entropy_len < buf_len ) |
| 563 | { |
| 564 | ret = 1; |
| 565 | } |
| 566 | |
| 567 | return( ret ); |
| 568 | } |
| 569 | |
| 570 | |
| 571 | static int mbedtls_entropy_source_self_test_check_bits( const unsigned char *buf, |
| 572 | size_t buf_len ) |
| 573 | { |
| 574 | unsigned char set= 0xFF; |
| 575 | unsigned char unset = 0x00; |
| 576 | size_t i; |
| 577 | |
| 578 | for( i = 0; i < buf_len; i++ ) |
| 579 | { |
| 580 | set &= buf[i]; |
| 581 | unset |= buf[i]; |
| 582 | } |
| 583 | |
| 584 | return( set == 0xFF || unset == 0x00 ); |
| 585 | } |
| 586 | |
| 587 | /* |
| 588 | * A test to ensure hat the entropy sources are functioning correctly |
| 589 | * and there is no obvious failure. The test performs the following checks: |
| 590 | * - The entropy source is not providing only 0s (all bits unset) or 1s (all |
| 591 | * bits set). |
| 592 | * - The entropy source is not providing values in a pattern. Because the |
| 593 | * hardware could be providing data in an arbitrary length, this check polls |
| 594 | * the hardware entropy source twice and compares the result to ensure they |
| 595 | * are not equal. |
| 596 | * - The error code returned by the entropy source is not an error. |
| 597 | */ |
| 598 | int mbedtls_entropy_source_self_test( int verbose ) |
| 599 | { |
| 600 | int ret = 0; |
| 601 | unsigned char buf0[2 * sizeof( unsigned long long int )]; |
| 602 | unsigned char buf1[2 * sizeof( unsigned long long int )]; |
| 603 | |
| 604 | if( verbose != 0 ) |
| 605 | mbedtls_printf( " ENTROPY_BIAS test: " ); |
| 606 | |
| 607 | memset( buf0, 0x00, sizeof( buf0 ) ); |
| 608 | memset( buf1, 0x00, sizeof( buf1 ) ); |
| 609 | |
| 610 | if( ( ret = mbedtls_entropy_source_self_test_gather( buf0, sizeof( buf0 ) ) ) != 0 ) |
| 611 | goto cleanup; |
| 612 | if( ( ret = mbedtls_entropy_source_self_test_gather( buf1, sizeof( buf1 ) ) ) != 0 ) |
| 613 | goto cleanup; |
| 614 | |
| 615 | /* Make sure that the returned values are not all 0 or 1 */ |
| 616 | if( ( ret = mbedtls_entropy_source_self_test_check_bits( buf0, sizeof( buf0 ) ) ) != 0 ) |
| 617 | goto cleanup; |
| 618 | if( ( ret = mbedtls_entropy_source_self_test_check_bits( buf1, sizeof( buf1 ) ) ) != 0 ) |
| 619 | goto cleanup; |
| 620 | |
| 621 | /* Make sure that the entropy source is not returning values in a |
| 622 | * pattern */ |
| 623 | ret = memcmp( buf0, buf1, sizeof( buf0 ) ) == 0; |
| 624 | |
| 625 | cleanup: |
| 626 | if( verbose != 0 ) |
| 627 | { |
| 628 | if( ret != 0 ) |
| 629 | mbedtls_printf( "failed\n" ); |
| 630 | else |
| 631 | mbedtls_printf( "passed\n" ); |
| 632 | |
| 633 | mbedtls_printf( "\n" ); |
| 634 | } |
| 635 | |
| 636 | return( ret != 0 ); |
| 637 | } |
| 638 | |
| 639 | #endif /* MBEDTLS_ENTROPY_HARDWARE_ALT */ |
| 640 | |
| 641 | /* |
| 642 | * The actual entropy quality is hard to test, but we can at least |
| 643 | * test that the functions don't cause errors and write the correct |
| 644 | * amount of data to buffers. |
| 645 | */ |
| 646 | int mbedtls_entropy_self_test( int verbose ) |
| 647 | { |
| 648 | int ret = 1; |
| 649 | #if !defined(MBEDTLS_TEST_NULL_ENTROPY) |
| 650 | mbedtls_entropy_context ctx; |
| 651 | unsigned char buf[MBEDTLS_ENTROPY_BLOCK_SIZE] = { 0 }; |
| 652 | unsigned char acc[MBEDTLS_ENTROPY_BLOCK_SIZE] = { 0 }; |
| 653 | size_t i, j; |
| 654 | #endif /* !MBEDTLS_TEST_NULL_ENTROPY */ |
| 655 | |
| 656 | if( verbose != 0 ) |
| 657 | mbedtls_printf( " ENTROPY test: " ); |
| 658 | |
| 659 | #if !defined(MBEDTLS_TEST_NULL_ENTROPY) |
| 660 | mbedtls_entropy_init( &ctx ); |
| 661 | |
| 662 | /* First do a gather to make sure we have default sources */ |
| 663 | if( ( ret = mbedtls_entropy_gather( &ctx ) ) != 0 ) |
| 664 | goto cleanup; |
| 665 | |
| 666 | ret = mbedtls_entropy_add_source( &ctx, entropy_dummy_source, NULL, 16, |
| 667 | MBEDTLS_ENTROPY_SOURCE_WEAK ); |
| 668 | if( ret != 0 ) |
| 669 | goto cleanup; |
| 670 | |
| 671 | if( ( ret = mbedtls_entropy_update_manual( &ctx, buf, sizeof buf ) ) != 0 ) |
| 672 | goto cleanup; |
| 673 | |
| 674 | /* |
| 675 | * To test that mbedtls_entropy_func writes correct number of bytes: |
| 676 | * - use the whole buffer and rely on ASan to detect overruns |
| 677 | * - collect entropy 8 times and OR the result in an accumulator: |
| 678 | * any byte should then be 0 with probably 2^(-64), so requiring |
| 679 | * each of the 32 or 64 bytes to be non-zero has a false failure rate |
| 680 | * of at most 2^(-58) which is acceptable. |
| 681 | */ |
| 682 | for( i = 0; i < 8; i++ ) |
| 683 | { |
| 684 | if( ( ret = mbedtls_entropy_func( &ctx, buf, sizeof( buf ) ) ) != 0 ) |
| 685 | goto cleanup; |
| 686 | |
| 687 | for( j = 0; j < sizeof( buf ); j++ ) |
| 688 | acc[j] |= buf[j]; |
| 689 | } |
| 690 | |
| 691 | for( j = 0; j < sizeof( buf ); j++ ) |
| 692 | { |
| 693 | if( acc[j] == 0 ) |
| 694 | { |
| 695 | ret = 1; |
| 696 | goto cleanup; |
| 697 | } |
| 698 | } |
| 699 | |
| 700 | #if defined(MBEDTLS_ENTROPY_HARDWARE_ALT) |
| 701 | if( ( ret = mbedtls_entropy_source_self_test( 0 ) ) != 0 ) |
| 702 | goto cleanup; |
| 703 | #endif |
| 704 | |
| 705 | cleanup: |
| 706 | mbedtls_entropy_free( &ctx ); |
| 707 | #endif /* !MBEDTLS_TEST_NULL_ENTROPY */ |
| 708 | |
| 709 | if( verbose != 0 ) |
| 710 | { |
| 711 | if( ret != 0 ) |
| 712 | mbedtls_printf( "failed\n" ); |
| 713 | else |
| 714 | mbedtls_printf( "passed\n" ); |
| 715 | |
| 716 | mbedtls_printf( "\n" ); |
| 717 | } |
| 718 | |
| 719 | return( ret != 0 ); |
| 720 | } |
| 721 | #endif /* MBEDTLS_SELF_TEST */ |
| 722 | |
| 723 | #endif /* MBEDTLS_ENTROPY_C */ |