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   1 /*
   2  *  CTR_DRBG implementation based on AES-256 (NIST SP 800-90)
   3  *
   4  *  Copyright (C) 2006-2015, 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  *  The NIST SP 800-90 DRBGs are described in the following publication.
  25  *
  26  *  http://csrc.nist.gov/publications/nistpubs/800-90/SP800-90revised_March2007.pdf
  27  */
  28
  29 #if !defined(MBEDTLS_CONFIG_FILE)
  30 #include "mbedtls/config.h"
  31 #else
  32 #include MBEDTLS_CONFIG_FILE
  33 #endif
  34
  35 #if defined(MBEDTLS_CTR_DRBG_C)
  36
  37 #include "mbedtls/ctr_drbg.h"
  38 #include "mbedtls/platform_util.h"
  39
  40 #include <string.h>
  41
  42 #if defined(MBEDTLS_FS_IO)
  43 #include <stdio.h>
  44 #endif
  45
  46 #if defined(MBEDTLS_SELF_TEST)
  47 #if defined(MBEDTLS_PLATFORM_C)
  48 #include "mbedtls/platform.h"
  49 #else
  50 #include <stdio.h>
  51 #define mbedtls_printf printf
  52 #endif /* MBEDTLS_PLATFORM_C */
  53 #endif /* MBEDTLS_SELF_TEST */
  54
  55 /*
  56  * CTR_DRBG context initialization
  57  */
  58 void mbedtls_ctr_drbg_init( mbedtls_ctr_drbg_context *ctx )
  59 {
  60     memset( ctx, 0, sizeof( mbedtls_ctr_drbg_context ) );
  61
  62 #if defined(MBEDTLS_THREADING_C)
  63     mbedtls_mutex_init( &ctx->mutex );
  64 #endif
  65 }
  66
  67 /*
  68  * Non-public function wrapped by mbedtls_ctr_drbg_seed(). Necessary to allow
  69  * NIST tests to succeed (which require known length fixed entropy)
  70  */
  71 int mbedtls_ctr_drbg_seed_entropy_len(
  72                    mbedtls_ctr_drbg_context *ctx,
  73                    int (*f_entropy)(void *, unsigned char *, size_t),
  74                    void *p_entropy,
  75                    const unsigned char *custom,
  76                    size_t len,
  77                    size_t entropy_len )
  78 {
  79     int ret;
  80     unsigned char key[MBEDTLS_CTR_DRBG_KEYSIZE];
  81
  82     memset( key, 0, MBEDTLS_CTR_DRBG_KEYSIZE );
  83
  84     mbedtls_aes_init( &ctx->aes_ctx );
  85
  86     ctx->f_entropy = f_entropy;
  87     ctx->p_entropy = p_entropy;
  88
  89     ctx->entropy_len = entropy_len;
  90     ctx->reseed_interval = MBEDTLS_CTR_DRBG_RESEED_INTERVAL;
  91
  92     /*
  93      * Initialize with an empty key
  94      */
  95     if( ( ret = mbedtls_aes_setkey_enc( &ctx->aes_ctx, key, MBEDTLS_CTR_DRBG_KEYBITS ) ) != 0 )
  96     {
  97         return( ret );
  98     }
  99
 100     if( ( ret = mbedtls_ctr_drbg_reseed( ctx, custom, len ) ) != 0 )
 101     {
 102         return( ret );
 103     }
 104     return( 0 );
 105 }
 106
 107 int mbedtls_ctr_drbg_seed( mbedtls_ctr_drbg_context *ctx,
 108                    int (*f_entropy)(void *, unsigned char *, size_t),
 109                    void *p_entropy,
 110                    const unsigned char *custom,
 111                    size_t len )
 112 {
 113     return( mbedtls_ctr_drbg_seed_entropy_len( ctx, f_entropy, p_entropy, custom, len,
 114                                        MBEDTLS_CTR_DRBG_ENTROPY_LEN ) );
 115 }
 116
 117 void mbedtls_ctr_drbg_free( mbedtls_ctr_drbg_context *ctx )
 118 {
 119     if( ctx == NULL )
 120         return;
 121
 122 #if defined(MBEDTLS_THREADING_C)
 123     mbedtls_mutex_free( &ctx->mutex );
 124 #endif
 125     mbedtls_aes_free( &ctx->aes_ctx );
 126     mbedtls_platform_zeroize( ctx, sizeof( mbedtls_ctr_drbg_context ) );
 127 }
 128
 129 void mbedtls_ctr_drbg_set_prediction_resistance( mbedtls_ctr_drbg_context *ctx, int resistance )
 130 {
 131     ctx->prediction_resistance = resistance;
 132 }
 133
 134 void mbedtls_ctr_drbg_set_entropy_len( mbedtls_ctr_drbg_context *ctx, size_t len )
 135 {
 136     ctx->entropy_len = len;
 137 }
 138
 139 void mbedtls_ctr_drbg_set_reseed_interval( mbedtls_ctr_drbg_context *ctx, int interval )
 140 {
 141     ctx->reseed_interval = interval;
 142 }
 143
 144 static int block_cipher_df( unsigned char *output,
 145                             const unsigned char *data, size_t data_len )
 146 {
 147     unsigned char buf[MBEDTLS_CTR_DRBG_MAX_SEED_INPUT + MBEDTLS_CTR_DRBG_BLOCKSIZE + 16];
 148     unsigned char tmp[MBEDTLS_CTR_DRBG_SEEDLEN];
 149     unsigned char key[MBEDTLS_CTR_DRBG_KEYSIZE];
 150     unsigned char chain[MBEDTLS_CTR_DRBG_BLOCKSIZE];
 151     unsigned char *p, *iv;
 152     mbedtls_aes_context aes_ctx;
 153     int ret = 0;
 154
 155     int i, j;
 156     size_t buf_len, use_len;
 157
 158     if( data_len > MBEDTLS_CTR_DRBG_MAX_SEED_INPUT )
 159         return( MBEDTLS_ERR_CTR_DRBG_INPUT_TOO_BIG );
 160
 161     memset( buf, 0, MBEDTLS_CTR_DRBG_MAX_SEED_INPUT + MBEDTLS_CTR_DRBG_BLOCKSIZE + 16 );
 162     mbedtls_aes_init( &aes_ctx );
 163
 164     /*
 165      * Construct IV (16 bytes) and S in buffer
 166      * IV = Counter (in 32-bits) padded to 16 with zeroes
 167      * S = Length input string (in 32-bits) || Length of output (in 32-bits) ||
 168      *     data || 0x80
 169      *     (Total is padded to a multiple of 16-bytes with zeroes)
 170      */
 171     p = buf + MBEDTLS_CTR_DRBG_BLOCKSIZE;
 172     *p++ = ( data_len >> 24 ) & 0xff;
 173     *p++ = ( data_len >> 16 ) & 0xff;
 174     *p++ = ( data_len >> 8  ) & 0xff;
 175     *p++ = ( data_len       ) & 0xff;
 176     p += 3;
 177     *p++ = MBEDTLS_CTR_DRBG_SEEDLEN;
 178     memcpy( p, data, data_len );
 179     p[data_len] = 0x80;
 180
 181     buf_len = MBEDTLS_CTR_DRBG_BLOCKSIZE + 8 + data_len + 1;
 182
 183     for( i = 0; i < MBEDTLS_CTR_DRBG_KEYSIZE; i++ )
 184         key[i] = i;
 185
 186     if( ( ret = mbedtls_aes_setkey_enc( &aes_ctx, key, MBEDTLS_CTR_DRBG_KEYBITS ) ) != 0 )
 187     {
 188         goto exit;
 189     }
 190
 191     /*
 192      * Reduce data to MBEDTLS_CTR_DRBG_SEEDLEN bytes of data
 193      */
 194     for( j = 0; j < MBEDTLS_CTR_DRBG_SEEDLEN; j += MBEDTLS_CTR_DRBG_BLOCKSIZE )
 195     {
 196         p = buf;
 197         memset( chain, 0, MBEDTLS_CTR_DRBG_BLOCKSIZE );
 198         use_len = buf_len;
 199
 200         while( use_len > 0 )
 201         {
 202             for( i = 0; i < MBEDTLS_CTR_DRBG_BLOCKSIZE; i++ )
 203                 chain[i] ^= p[i];
 204             p += MBEDTLS_CTR_DRBG_BLOCKSIZE;
 205             use_len -= ( use_len >= MBEDTLS_CTR_DRBG_BLOCKSIZE ) ?
 206                        MBEDTLS_CTR_DRBG_BLOCKSIZE : use_len;
 207
 208             if( ( ret = mbedtls_aes_crypt_ecb( &aes_ctx, MBEDTLS_AES_ENCRYPT, chain, chain ) ) != 0 )
 209             {
 210                 goto exit;
 211             }
 212         }
 213
 214         memcpy( tmp + j, chain, MBEDTLS_CTR_DRBG_BLOCKSIZE );
 215
 216         /*
 217          * Update IV
 218          */
 219         buf[3]++;
 220     }
 221
 222     /*
 223      * Do final encryption with reduced data
 224      */
 225     if( ( ret = mbedtls_aes_setkey_enc( &aes_ctx, tmp, MBEDTLS_CTR_DRBG_KEYBITS ) ) != 0 )
 226     {
 227         goto exit;
 228     }
 229     iv = tmp + MBEDTLS_CTR_DRBG_KEYSIZE;
 230     p = output;
 231
 232     for( j = 0; j < MBEDTLS_CTR_DRBG_SEEDLEN; j += MBEDTLS_CTR_DRBG_BLOCKSIZE )
 233     {
 234         if( ( ret = mbedtls_aes_crypt_ecb( &aes_ctx, MBEDTLS_AES_ENCRYPT, iv, iv ) ) != 0 )
 235         {
 236             goto exit;
 237         }
 238         memcpy( p, iv, MBEDTLS_CTR_DRBG_BLOCKSIZE );
 239         p += MBEDTLS_CTR_DRBG_BLOCKSIZE;
 240     }
 241 exit:
 242     mbedtls_aes_free( &aes_ctx );
 243     /*
 244     * tidy up the stack
 245     */
 246     mbedtls_platform_zeroize( buf, sizeof( buf ) );
 247     mbedtls_platform_zeroize( tmp, sizeof( tmp ) );
 248     mbedtls_platform_zeroize( key, sizeof( key ) );
 249     mbedtls_platform_zeroize( chain, sizeof( chain ) );
 250     if( 0 != ret )
 251     {
 252         /*
 253         * wipe partial seed from memory
 254         */
 255         mbedtls_platform_zeroize( output, MBEDTLS_CTR_DRBG_SEEDLEN );
 256     }
 257
 258     return( ret );
 259 }
 260
 261 static int ctr_drbg_update_internal( mbedtls_ctr_drbg_context *ctx,
 262                               const unsigned char data[MBEDTLS_CTR_DRBG_SEEDLEN] )
 263 {
 264     unsigned char tmp[MBEDTLS_CTR_DRBG_SEEDLEN];
 265     unsigned char *p = tmp;
 266     int i, j;
 267     int ret = 0;
 268
 269     memset( tmp, 0, MBEDTLS_CTR_DRBG_SEEDLEN );
 270
 271     for( j = 0; j < MBEDTLS_CTR_DRBG_SEEDLEN; j += MBEDTLS_CTR_DRBG_BLOCKSIZE )
 272     {
 273         /*
 274          * Increase counter
 275          */
 276         for( i = MBEDTLS_CTR_DRBG_BLOCKSIZE; i > 0; i-- )
 277             if( ++ctx->counter[i - 1] != 0 )
 278                 break;
 279
 280         /*
 281          * Crypt counter block
 282          */
 283         if( ( ret = mbedtls_aes_crypt_ecb( &ctx->aes_ctx, MBEDTLS_AES_ENCRYPT, ctx->counter, p ) ) != 0 )
 284         {
 285             return( ret );
 286         }
 287
 288         p += MBEDTLS_CTR_DRBG_BLOCKSIZE;
 289     }
 290
 291     for( i = 0; i < MBEDTLS_CTR_DRBG_SEEDLEN; i++ )
 292         tmp[i] ^= data[i];
 293
 294     /*
 295      * Update key and counter
 296      */
 297     if( ( ret = mbedtls_aes_setkey_enc( &ctx->aes_ctx, tmp, MBEDTLS_CTR_DRBG_KEYBITS ) ) != 0 )
 298     {
 299         return( ret );
 300     }
 301     memcpy( ctx->counter, tmp + MBEDTLS_CTR_DRBG_KEYSIZE, MBEDTLS_CTR_DRBG_BLOCKSIZE );
 302
 303     return( 0 );
 304 }
 305
 306 void mbedtls_ctr_drbg_update( mbedtls_ctr_drbg_context *ctx,
 307                       const unsigned char *additional, size_t add_len )
 308 {
 309     unsigned char add_input[MBEDTLS_CTR_DRBG_SEEDLEN];
 310
 311     if( add_len > 0 )
 312     {
 313         /* MAX_INPUT would be more logical here, but we have to match
 314          * block_cipher_df()'s limits since we can't propagate errors */
 315         if( add_len > MBEDTLS_CTR_DRBG_MAX_SEED_INPUT )
 316             add_len = MBEDTLS_CTR_DRBG_MAX_SEED_INPUT;
 317
 318         block_cipher_df( add_input, additional, add_len );
 319         ctr_drbg_update_internal( ctx, add_input );
 320     }
 321 }
 322
 323 int mbedtls_ctr_drbg_reseed( mbedtls_ctr_drbg_context *ctx,
 324                      const unsigned char *additional, size_t len )
 325 {
 326     unsigned char seed[MBEDTLS_CTR_DRBG_MAX_SEED_INPUT];
 327     size_t seedlen = 0;
 328     int ret;
 329
 330     if( ctx->entropy_len > MBEDTLS_CTR_DRBG_MAX_SEED_INPUT ||
 331         len > MBEDTLS_CTR_DRBG_MAX_SEED_INPUT - ctx->entropy_len )
 332         return( MBEDTLS_ERR_CTR_DRBG_INPUT_TOO_BIG );
 333
 334     memset( seed, 0, MBEDTLS_CTR_DRBG_MAX_SEED_INPUT );
 335
 336     /*
 337      * Gather entropy_len bytes of entropy to seed state
 338      */
 339     if( 0 != ctx->f_entropy( ctx->p_entropy, seed,
 340                              ctx->entropy_len ) )
 341     {
 342         return( MBEDTLS_ERR_CTR_DRBG_ENTROPY_SOURCE_FAILED );
 343     }
 344
 345     seedlen += ctx->entropy_len;
 346
 347     /*
 348      * Add additional data
 349      */
 350     if( additional && len )
 351     {
 352         memcpy( seed + seedlen, additional, len );
 353         seedlen += len;
 354     }
 355
 356     /*
 357      * Reduce to 384 bits
 358      */
 359     if( ( ret = block_cipher_df( seed, seed, seedlen ) ) != 0 )
 360     {
 361         return( ret );
 362     }
 363
 364     /*
 365      * Update state
 366      */
 367     if( ( ret = ctr_drbg_update_internal( ctx, seed ) ) != 0 )
 368     {
 369         return( ret );
 370     }
 371     ctx->reseed_counter = 1;
 372
 373     return( 0 );
 374 }
 375
 376 int mbedtls_ctr_drbg_random_with_add( void *p_rng,
 377                               unsigned char *output, size_t output_len,
 378                               const unsigned char *additional, size_t add_len )
 379 {
 380     int ret = 0;
 381     mbedtls_ctr_drbg_context *ctx = (mbedtls_ctr_drbg_context *) p_rng;
 382     unsigned char add_input[MBEDTLS_CTR_DRBG_SEEDLEN];
 383     unsigned char *p = output;
 384     unsigned char tmp[MBEDTLS_CTR_DRBG_BLOCKSIZE];
 385     int i;
 386     size_t use_len;
 387
 388     if( output_len > MBEDTLS_CTR_DRBG_MAX_REQUEST )
 389         return( MBEDTLS_ERR_CTR_DRBG_REQUEST_TOO_BIG );
 390
 391     if( add_len > MBEDTLS_CTR_DRBG_MAX_INPUT )
 392         return( MBEDTLS_ERR_CTR_DRBG_INPUT_TOO_BIG );
 393
 394     memset( add_input, 0, MBEDTLS_CTR_DRBG_SEEDLEN );
 395
 396     if( ctx->reseed_counter > ctx->reseed_interval ||
 397         ctx->prediction_resistance )
 398     {
 399         if( ( ret = mbedtls_ctr_drbg_reseed( ctx, additional, add_len ) ) != 0 )
 400         {
 401             return( ret );
 402         }
 403         add_len = 0;
 404     }
 405
 406     if( add_len > 0 )
 407     {
 408         if( ( ret = block_cipher_df( add_input, additional, add_len ) ) != 0 )
 409         {
 410             return( ret );
 411         }
 412         if( ( ret = ctr_drbg_update_internal( ctx, add_input ) ) != 0 )
 413         {
 414             return( ret );
 415         }
 416     }
 417
 418     while( output_len > 0 )
 419     {
 420         /*
 421          * Increase counter
 422          */
 423         for( i = MBEDTLS_CTR_DRBG_BLOCKSIZE; i > 0; i-- )
 424             if( ++ctx->counter[i - 1] != 0 )
 425                 break;
 426
 427         /*
 428          * Crypt counter block
 429          */
 430         if( ( ret = mbedtls_aes_crypt_ecb( &ctx->aes_ctx, MBEDTLS_AES_ENCRYPT, ctx->counter, tmp ) ) != 0 )
 431         {
 432             return( ret );
 433         }
 434
 435         use_len = ( output_len > MBEDTLS_CTR_DRBG_BLOCKSIZE ) ? MBEDTLS_CTR_DRBG_BLOCKSIZE :
 436                                                        output_len;
 437         /*
 438          * Copy random block to destination
 439          */
 440         memcpy( p, tmp, use_len );
 441         p += use_len;
 442         output_len -= use_len;
 443     }
 444
 445     if( ( ret = ctr_drbg_update_internal( ctx, add_input ) ) != 0 )
 446     {
 447         return( ret );
 448     }
 449
 450     ctx->reseed_counter++;
 451
 452     return( 0 );
 453 }
 454
 455 int mbedtls_ctr_drbg_random( void *p_rng, unsigned char *output, size_t output_len )
 456 {
 457     int ret;
 458     mbedtls_ctr_drbg_context *ctx = (mbedtls_ctr_drbg_context *) p_rng;
 459
 460 #if defined(MBEDTLS_THREADING_C)
 461     if( ( ret = mbedtls_mutex_lock( &ctx->mutex ) ) != 0 )
 462         return( ret );
 463 #endif
 464
 465     ret = mbedtls_ctr_drbg_random_with_add( ctx, output, output_len, NULL, 0 );
 466
 467 #if defined(MBEDTLS_THREADING_C)
 468     if( mbedtls_mutex_unlock( &ctx->mutex ) != 0 )
 469         return( MBEDTLS_ERR_THREADING_MUTEX_ERROR );
 470 #endif
 471
 472     return( ret );
 473 }
 474
 475 #if defined(MBEDTLS_FS_IO)
 476 int mbedtls_ctr_drbg_write_seed_file( mbedtls_ctr_drbg_context *ctx, const char *path )
 477 {
 478     int ret = MBEDTLS_ERR_CTR_DRBG_FILE_IO_ERROR;
 479     FILE *f;
 480     unsigned char buf[ MBEDTLS_CTR_DRBG_MAX_INPUT ];
 481
 482     if( ( f = fopen( path, "wb" ) ) == NULL )
 483         return( MBEDTLS_ERR_CTR_DRBG_FILE_IO_ERROR );
 484
 485     if( ( ret = mbedtls_ctr_drbg_random( ctx, buf, MBEDTLS_CTR_DRBG_MAX_INPUT ) ) != 0 )
 486         goto exit;
 487
 488     if( fwrite( buf, 1, MBEDTLS_CTR_DRBG_MAX_INPUT, f ) != MBEDTLS_CTR_DRBG_MAX_INPUT )
 489         ret = MBEDTLS_ERR_CTR_DRBG_FILE_IO_ERROR;
 490     else
 491         ret = 0;
 492
 493 exit:
 494     mbedtls_platform_zeroize( buf, sizeof( buf ) );
 495
 496     fclose( f );
 497     return( ret );
 498 }
 499
 500 int mbedtls_ctr_drbg_update_seed_file( mbedtls_ctr_drbg_context *ctx, const char *path )
 501 {
 502     int ret = 0;
 503     FILE *f;
 504     size_t n;
 505     unsigned char buf[ MBEDTLS_CTR_DRBG_MAX_INPUT ];
 506
 507     if( ( f = fopen( path, "rb" ) ) == NULL )
 508         return( MBEDTLS_ERR_CTR_DRBG_FILE_IO_ERROR );
 509
 510     fseek( f, 0, SEEK_END );
 511     n = (size_t) ftell( f );
 512     fseek( f, 0, SEEK_SET );
 513
 514     if( n > MBEDTLS_CTR_DRBG_MAX_INPUT )
 515     {
 516         fclose( f );
 517         return( MBEDTLS_ERR_CTR_DRBG_INPUT_TOO_BIG );
 518     }
 519
 520     if( fread( buf, 1, n, f ) != n )
 521         ret = MBEDTLS_ERR_CTR_DRBG_FILE_IO_ERROR;
 522     else
 523         mbedtls_ctr_drbg_update( ctx, buf, n );
 524
 525     fclose( f );
 526
 527     mbedtls_platform_zeroize( buf, sizeof( buf ) );
 528
 529     if( ret != 0 )
 530         return( ret );
 531
 532     return( mbedtls_ctr_drbg_write_seed_file( ctx, path ) );
 533 }
 534 #endif /* MBEDTLS_FS_IO */
 535
 536 #if defined(MBEDTLS_SELF_TEST)
 537
 538 static const unsigned char entropy_source_pr[96] =
 539     { 0xc1, 0x80, 0x81, 0xa6, 0x5d, 0x44, 0x02, 0x16,
 540       0x19, 0xb3, 0xf1, 0x80, 0xb1, 0xc9, 0x20, 0x02,
 541       0x6a, 0x54, 0x6f, 0x0c, 0x70, 0x81, 0x49, 0x8b,
 542       0x6e, 0xa6, 0x62, 0x52, 0x6d, 0x51, 0xb1, 0xcb,
 543       0x58, 0x3b, 0xfa, 0xd5, 0x37, 0x5f, 0xfb, 0xc9,
 544       0xff, 0x46, 0xd2, 0x19, 0xc7, 0x22, 0x3e, 0x95,
 545       0x45, 0x9d, 0x82, 0xe1, 0xe7, 0x22, 0x9f, 0x63,
 546       0x31, 0x69, 0xd2, 0x6b, 0x57, 0x47, 0x4f, 0xa3,
 547       0x37, 0xc9, 0x98, 0x1c, 0x0b, 0xfb, 0x91, 0x31,
 548       0x4d, 0x55, 0xb9, 0xe9, 0x1c, 0x5a, 0x5e, 0xe4,
 549       0x93, 0x92, 0xcf, 0xc5, 0x23, 0x12, 0xd5, 0x56,
 550       0x2c, 0x4a, 0x6e, 0xff, 0xdc, 0x10, 0xd0, 0x68 };
 551
 552 static const unsigned char entropy_source_nopr[64] =
 553     { 0x5a, 0x19, 0x4d, 0x5e, 0x2b, 0x31, 0x58, 0x14,
 554       0x54, 0xde, 0xf6, 0x75, 0xfb, 0x79, 0x58, 0xfe,
 555       0xc7, 0xdb, 0x87, 0x3e, 0x56, 0x89, 0xfc, 0x9d,
 556       0x03, 0x21, 0x7c, 0x68, 0xd8, 0x03, 0x38, 0x20,
 557       0xf9, 0xe6, 0x5e, 0x04, 0xd8, 0x56, 0xf3, 0xa9,
 558       0xc4, 0x4a, 0x4c, 0xbd, 0xc1, 0xd0, 0x08, 0x46,
 559       0xf5, 0x98, 0x3d, 0x77, 0x1c, 0x1b, 0x13, 0x7e,
 560       0x4e, 0x0f, 0x9d, 0x8e, 0xf4, 0x09, 0xf9, 0x2e };
 561
 562 static const unsigned char nonce_pers_pr[16] =
 563     { 0xd2, 0x54, 0xfc, 0xff, 0x02, 0x1e, 0x69, 0xd2,
 564       0x29, 0xc9, 0xcf, 0xad, 0x85, 0xfa, 0x48, 0x6c };
 565
 566 static const unsigned char nonce_pers_nopr[16] =
 567     { 0x1b, 0x54, 0xb8, 0xff, 0x06, 0x42, 0xbf, 0xf5,
 568       0x21, 0xf1, 0x5c, 0x1c, 0x0b, 0x66, 0x5f, 0x3f };
 569
 570 static const unsigned char result_pr[16] =
 571     { 0x34, 0x01, 0x16, 0x56, 0xb4, 0x29, 0x00, 0x8f,
 572       0x35, 0x63, 0xec, 0xb5, 0xf2, 0x59, 0x07, 0x23 };
 573
 574 static const unsigned char result_nopr[16] =
 575     { 0xa0, 0x54, 0x30, 0x3d, 0x8a, 0x7e, 0xa9, 0x88,
 576       0x9d, 0x90, 0x3e, 0x07, 0x7c, 0x6f, 0x21, 0x8f };
 577
 578 static size_t test_offset;
 579 static int ctr_drbg_self_test_entropy( void *data, unsigned char *buf,
 580                                        size_t len )
 581 {
 582     const unsigned char *p = data;
 583     memcpy( buf, p + test_offset, len );
 584     test_offset += len;
 585     return( 0 );
 586 }
 587
 588 #define CHK( c )    if( (c) != 0 )                          \
 589                     {                                       \
 590                         if( verbose != 0 )                  \
 591                             mbedtls_printf( "failed\n" );  \
 592                         return( 1 );                        \
 593                     }
 594
 595 /*
 596  * Checkup routine
 597  */
 598 int mbedtls_ctr_drbg_self_test( int verbose )
 599 {
 600     mbedtls_ctr_drbg_context ctx;
 601     unsigned char buf[16];
 602
 603     mbedtls_ctr_drbg_init( &ctx );
 604
 605     /*
 606      * Based on a NIST CTR_DRBG test vector (PR = True)
 607      */
 608     if( verbose != 0 )
 609         mbedtls_printf( "  CTR_DRBG (PR = TRUE) : " );
 610
 611     test_offset = 0;
 612     CHK( mbedtls_ctr_drbg_seed_entropy_len( &ctx, ctr_drbg_self_test_entropy,
 613                                 (void *) entropy_source_pr, nonce_pers_pr, 16, 32 ) );
 614     mbedtls_ctr_drbg_set_prediction_resistance( &ctx, MBEDTLS_CTR_DRBG_PR_ON );
 615     CHK( mbedtls_ctr_drbg_random( &ctx, buf, MBEDTLS_CTR_DRBG_BLOCKSIZE ) );
 616     CHK( mbedtls_ctr_drbg_random( &ctx, buf, MBEDTLS_CTR_DRBG_BLOCKSIZE ) );
 617     CHK( memcmp( buf, result_pr, MBEDTLS_CTR_DRBG_BLOCKSIZE ) );
 618
 619     mbedtls_ctr_drbg_free( &ctx );
 620
 621     if( verbose != 0 )
 622         mbedtls_printf( "passed\n" );
 623
 624     /*
 625      * Based on a NIST CTR_DRBG test vector (PR = FALSE)
 626      */
 627     if( verbose != 0 )
 628         mbedtls_printf( "  CTR_DRBG (PR = FALSE): " );
 629
 630     mbedtls_ctr_drbg_init( &ctx );
 631
 632     test_offset = 0;
 633     CHK( mbedtls_ctr_drbg_seed_entropy_len( &ctx, ctr_drbg_self_test_entropy,
 634                             (void *) entropy_source_nopr, nonce_pers_nopr, 16, 32 ) );
 635     CHK( mbedtls_ctr_drbg_random( &ctx, buf, 16 ) );
 636     CHK( mbedtls_ctr_drbg_reseed( &ctx, NULL, 0 ) );
 637     CHK( mbedtls_ctr_drbg_random( &ctx, buf, 16 ) );
 638     CHK( memcmp( buf, result_nopr, 16 ) );
 639
 640     mbedtls_ctr_drbg_free( &ctx );
 641
 642     if( verbose != 0 )
 643         mbedtls_printf( "passed\n" );
 644
 645     if( verbose != 0 )
 646             mbedtls_printf( "\n" );
 647
 648     return( 0 );
 649 }
 650 #endif /* MBEDTLS_SELF_TEST */
 651
 652 #endif /* MBEDTLS_CTR_DRBG_C */