fips/rand/fips_drbg_lib.c

   1 /* fips/rand/fips_drbg_lib.c */
   2 /* Written by Dr Stephen N Henson (steve@openssl.org) for the OpenSSL
   3  * project.
   4  */
   5 /* ====================================================================
   6  * Copyright (c) 2011 The OpenSSL Project.  All rights reserved.
   7  *
   8  * Redistribution and use in source and binary forms, with or without
   9  * modification, are permitted provided that the following conditions
  10  * are met:
  11  *
  12  * 1. Redistributions of source code must retain the above copyright
  13  *    notice, this list of conditions and the following disclaimer.
  14  *
  15  * 2. Redistributions in binary form must reproduce the above copyright
  16  *    notice, this list of conditions and the following disclaimer in
  17  *    the documentation and/or other materials provided with the
  18  *    distribution.
  19  *
  20  * 3. All advertising materials mentioning features or use of this
  21  *    software must display the following acknowledgment:
  22  *    "This product includes software developed by the OpenSSL Project
  23  *    for use in the OpenSSL Toolkit. (http://www.OpenSSL.org/)"
  24  *
  25  * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
  26  *    endorse or promote products derived from this software without
  27  *    prior written permission. For written permission, please contact
  28  *    licensing@OpenSSL.org.
  29  *
  30  * 5. Products derived from this software may not be called "OpenSSL"
  31  *    nor may "OpenSSL" appear in their names without prior written
  32  *    permission of the OpenSSL Project.
  33  *
  34  * 6. Redistributions of any form whatsoever must retain the following
  35  *    acknowledgment:
  36  *    "This product includes software developed by the OpenSSL Project
  37  *    for use in the OpenSSL Toolkit (http://www.OpenSSL.org/)"
  38  *
  39  * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
  40  * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  41  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  42  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE OpenSSL PROJECT OR
  43  * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  44  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  45  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  46  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  47  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
  48  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  49  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
  50  * OF THE POSSIBILITY OF SUCH DAMAGE.
  51  * ====================================================================
  52  */
  53
  54 #define OPENSSL_FIPSAPI
  55
  56 #include <string.h>
  57 #include <openssl/crypto.h>
  58 #include <openssl/err.h>
  59 #include <openssl/fips_rand.h>
  60 #include "fips_rand_lcl.h"
  61
  62 /* Support framework for SP800-90 DRBGs */
  63
  64 int FIPS_drbg_init(DRBG_CTX *dctx, int type, unsigned int flags)
  65         {
  66         int rv;
  67         memset(dctx, 0, sizeof(DRBG_CTX));
  68         dctx->status = DRBG_STATUS_UNINITIALISED;
  69         dctx->flags = flags;
  70         dctx->type = type;
  71
  72         dctx->entropy_blocklen = 0;
  73         dctx->health_check_cnt = 0;
  74         dctx->health_check_interval = DRBG_HEALTH_INTERVAL;
  75
  76         rv = fips_drbg_hash_init(dctx);
  77
  78         if (rv == -2)
  79                 rv = fips_drbg_ctr_init(dctx);
  80         if (rv == -2)
  81                 rv = fips_drbg_hmac_init(dctx);
  82         if (rv == -2)
  83                 rv = fips_drbg_ec_init(dctx);
  84
  85         if (rv <= 0)
  86                 {
  87                 if (rv == -2)
  88                         FIPSerr(FIPS_F_FIPS_DRBG_INIT, FIPS_R_UNSUPPORTED_DRBG_TYPE);
  89                 else
  90                         FIPSerr(FIPS_F_FIPS_DRBG_INIT, FIPS_R_ERROR_INITIALISING_DRBG);
  91                 }
  92
  93         /* If not in test mode run selftests on DRBG of the same type */
  94
  95         if (!(dctx->flags & DRBG_FLAG_TEST))
  96                 {
  97                 DRBG_CTX tctx;
  98                 if (!fips_drbg_kat(&tctx, type, flags | DRBG_FLAG_TEST))
  99                         {
 100                         FIPSerr(FIPS_F_FIPS_DRBG_INIT, FIPS_R_SELFTEST_FAILURE);
 101                         dctx->status = DRBG_STATUS_ERROR;
 102                         return 0;
 103                         }
 104                 }
 105
 106         return rv;
 107         }
 108
 109 DRBG_CTX *FIPS_drbg_new(int type, unsigned int flags)
 110         {
 111         DRBG_CTX *dctx;
 112         dctx = OPENSSL_malloc(sizeof(DRBG_CTX));
 113         if (!dctx)
 114                 {
 115                 FIPSerr(FIPS_F_FIPS_DRBG_NEW, ERR_R_MALLOC_FAILURE);
 116                 return NULL;
 117                 }
 118
 119         if (type == 0)
 120                 {
 121                 memset(dctx, 0, sizeof(DRBG_CTX));
 122                 dctx->type = 0;
 123                 dctx->status = DRBG_STATUS_UNINITIALISED;
 124                 return dctx;
 125                 }
 126
 127         if (FIPS_drbg_init(dctx, type, flags) <= 0)
 128                 {
 129                 OPENSSL_free(dctx);
 130                 return NULL;
 131                 }
 132
 133         return dctx;
 134         }
 135
 136 void FIPS_drbg_free(DRBG_CTX *dctx)
 137         {
 138         if (dctx->uninstantiate)
 139                 dctx->uninstantiate(dctx);
 140         OPENSSL_cleanse(&dctx->d, sizeof(dctx->d));
 141         OPENSSL_free(dctx);
 142         }
 143
 144 static size_t fips_get_entropy(DRBG_CTX *dctx, unsigned char **pout,
 145                                 int entropy, size_t min_len, size_t max_len)
 146         {
 147         unsigned char *tout, *p;
 148         size_t bl = dctx->entropy_blocklen, rv;
 149         if (dctx->flags & DRBG_FLAG_TEST || !bl)
 150                 return dctx->get_entropy(dctx, pout, entropy, min_len, max_len);
 151         rv = dctx->get_entropy(dctx, &tout, entropy + bl,
 152                                 min_len + bl, max_len + bl);
 153         *pout = tout + bl;
 154         if (rv < (min_len + bl) || (rv % bl))
 155                 return 0;
 156         /* Compare consecutive blocks for continuous PRNG test */
 157         for (p = tout; p < tout + rv - bl; p += bl)
 158                 {
 159                 if (!memcmp(p, p + bl, bl))
 160                         {
 161                         FIPSerr(FIPS_F_FIPS_GET_ENTROPY, FIPS_R_ENTROPY_SOURCE_STUCK);
 162                         return 0;
 163                         }
 164                 }
 165         rv -= bl;
 166         if (rv > max_len)
 167                 return max_len;
 168         return rv;
 169         }
 170
 171 static void fips_cleanup_entropy(DRBG_CTX *dctx,
 172                                         unsigned char *out, size_t olen)
 173         {
 174         size_t bl;
 175         if (dctx->flags & DRBG_FLAG_TEST)
 176                 bl = 0;
 177         else
 178                 bl = dctx->entropy_blocklen;
 179         /* Call cleanup with original arguments */
 180         dctx->cleanup_entropy(dctx, out - bl, olen + bl);
 181         }
 182
 183
 184 int FIPS_drbg_instantiate(DRBG_CTX *dctx,
 185                                 const unsigned char *pers, size_t perslen)
 186         {
 187         size_t entlen = 0, noncelen = 0;
 188         unsigned char *nonce = NULL, *entropy = NULL;
 189
 190 #if 0
 191         /* Put here so error script picks them up */
 192         FIPSerr(FIPS_F_FIPS_DRBG_INSTANTIATE,
 193                                 FIPS_R_PERSONALISATION_STRING_TOO_LONG);
 194         FIPSerr(FIPS_F_FIPS_DRBG_INSTANTIATE, FIPS_R_IN_ERROR_STATE);
 195         FIPSerr(FIPS_F_FIPS_DRBG_INSTANTIATE, FIPS_R_ALREADY_INSTANTIATED);
 196         FIPSerr(FIPS_F_FIPS_DRBG_INSTANTIATE, FIPS_R_ERROR_RETRIEVING_ENTROPY);
 197         FIPSerr(FIPS_F_FIPS_DRBG_INSTANTIATE, FIPS_R_ERROR_RETRIEVING_NONCE);
 198         FIPSerr(FIPS_F_FIPS_DRBG_INSTANTIATE, FIPS_R_INSTANTIATE_ERROR);
 199 #endif
 200
 201         int r = 0;
 202
 203         if (perslen > dctx->max_pers)
 204                 {
 205                 r = FIPS_R_PERSONALISATION_STRING_TOO_LONG;
 206                 goto end;
 207                 }
 208
 209         if (dctx->status != DRBG_STATUS_UNINITIALISED)
 210                 {
 211                 if (dctx->status == DRBG_STATUS_ERROR)
 212                         r = FIPS_R_IN_ERROR_STATE;
 213                 else
 214                         r = FIPS_R_ALREADY_INSTANTIATED;
 215                 goto end;
 216                 }
 217
 218         dctx->status = DRBG_STATUS_ERROR;
 219
 220         entlen = fips_get_entropy(dctx, &entropy, dctx->strength,
 221                                 dctx->min_entropy, dctx->max_entropy);
 222
 223         if (entlen < dctx->min_entropy || entlen > dctx->max_entropy)
 224                 {
 225                 r = FIPS_R_ERROR_RETRIEVING_ENTROPY;
 226                 goto end;
 227                 }
 228
 229         if (dctx->max_nonce > 0)
 230                 {
 231                 noncelen = dctx->get_nonce(dctx, &nonce,
 232                                         dctx->strength / 2,
 233                                         dctx->min_nonce, dctx->max_nonce);
 234
 235                 if (noncelen < dctx->min_nonce || noncelen > dctx->max_nonce)
 236                         {
 237                         r = FIPS_R_ERROR_RETRIEVING_NONCE;
 238                         goto end;
 239                         }
 240
 241                 }
 242
 243         if (!dctx->instantiate(dctx,
 244                                 entropy, entlen,
 245                                 nonce, noncelen,
 246                                 pers, perslen))
 247                 {
 248                 r = FIPS_R_ERROR_INSTANTIATING_DRBG;
 249                 goto end;
 250                 }
 251
 252
 253         dctx->status = DRBG_STATUS_READY;
 254         if (!(dctx->flags & DRBG_CUSTOM_RESEED))
 255                 dctx->reseed_counter = 1;
 256
 257         end:
 258
 259         if (entropy && dctx->cleanup_entropy)
 260                 fips_cleanup_entropy(dctx, entropy, entlen);
 261
 262         if (nonce && dctx->cleanup_nonce)
 263                 dctx->cleanup_nonce(dctx, nonce, noncelen);
 264
 265         if (dctx->status == DRBG_STATUS_READY)
 266                 return 1;
 267
 268         if (r && !(dctx->flags & DRBG_FLAG_NOERR))
 269                 FIPSerr(FIPS_F_FIPS_DRBG_INSTANTIATE, r);
 270
 271         return 0;
 272
 273         }
 274
 275 int FIPS_drbg_reseed(DRBG_CTX *dctx,
 276                         const unsigned char *adin, size_t adinlen)
 277         {
 278         unsigned char *entropy = NULL;
 279         size_t entlen;
 280         int r = 0;
 281
 282 #if 0
 283         FIPSerr(FIPS_F_FIPS_DRBG_RESEED, FIPS_R_NOT_INSTANTIATED);
 284         FIPSerr(FIPS_F_FIPS_DRBG_RESEED, FIPS_R_ADDITIONAL_INPUT_TOO_LONG);
 285 #endif
 286         if (dctx->status != DRBG_STATUS_READY
 287                 && dctx->status != DRBG_STATUS_RESEED)
 288                 {
 289                 if (dctx->status == DRBG_STATUS_ERROR)
 290                         r = FIPS_R_IN_ERROR_STATE;
 291                 else if(dctx->status == DRBG_STATUS_UNINITIALISED)
 292                         r = FIPS_R_NOT_INSTANTIATED;
 293                 goto end;
 294                 }
 295
 296         if (!adin)
 297                 adinlen = 0;
 298         else if (adinlen > dctx->max_adin)
 299                 {
 300                 r = FIPS_R_ADDITIONAL_INPUT_TOO_LONG;
 301                 goto end;
 302                 }
 303
 304         dctx->status = DRBG_STATUS_ERROR;
 305
 306         entlen = fips_get_entropy(dctx, &entropy, dctx->strength,
 307                                 dctx->min_entropy, dctx->max_entropy);
 308
 309         if (entlen < dctx->min_entropy || entlen > dctx->max_entropy)
 310                 {
 311                 r = FIPS_R_ERROR_RETRIEVING_ENTROPY;
 312                 goto end;
 313                 }
 314
 315         if (!dctx->reseed(dctx, entropy, entlen, adin, adinlen))
 316                 goto end;
 317
 318         dctx->status = DRBG_STATUS_READY;
 319         if (!(dctx->flags & DRBG_CUSTOM_RESEED))
 320                 dctx->reseed_counter = 1;
 321         end:
 322
 323         if (entropy && dctx->cleanup_entropy)
 324                 fips_cleanup_entropy(dctx, entropy, entlen);
 325
 326         if (dctx->status == DRBG_STATUS_READY)
 327                 return 1;
 328
 329         if (r && !(dctx->flags & DRBG_FLAG_NOERR))
 330                 FIPSerr(FIPS_F_FIPS_DRBG_RESEED, r);
 331
 332         return 0;
 333         }
 334
 335 static int fips_drbg_check(DRBG_CTX *dctx)
 336         {
 337         if (dctx->flags & DRBG_FLAG_TEST)
 338                 return 1;
 339         dctx->health_check_cnt++;
 340         if (dctx->health_check_cnt >= dctx->health_check_interval)
 341                 {
 342                 DRBG_CTX tctx;
 343                 if (!fips_drbg_kat(&tctx, dctx->type,
 344                                                 dctx->flags | DRBG_FLAG_TEST))
 345                         {
 346                         FIPSerr(FIPS_F_FIPS_DRBG_CHECK, FIPS_R_SELFTEST_FAILURE);
 347                         dctx->status = DRBG_STATUS_ERROR;
 348                         return 0;
 349                         }
 350                 dctx->health_check_cnt = 0;
 351                 }
 352         return 1;
 353         }
 354
 355 int FIPS_drbg_generate(DRBG_CTX *dctx, unsigned char *out, size_t outlen,
 356                         int strength, int prediction_resistance,
 357                         const unsigned char *adin, size_t adinlen)
 358         {
 359         int r = 0;
 360
 361         if (!fips_drbg_check(dctx))
 362                 return 0;
 363
 364         if (dctx->status != DRBG_STATUS_READY
 365                 && dctx->status != DRBG_STATUS_RESEED)
 366                 {
 367                 if (dctx->status == DRBG_STATUS_ERROR)
 368                         r = FIPS_R_IN_ERROR_STATE;
 369                 else if(dctx->status == DRBG_STATUS_UNINITIALISED)
 370                         r = FIPS_R_NOT_INSTANTIATED;
 371                 goto end;
 372                 }
 373
 374         if (outlen > dctx->max_request)
 375                 {
 376                 r = FIPS_R_REQUEST_TOO_LARGE_FOR_DRBG;
 377                 return 0;
 378                 }
 379
 380         if (strength > dctx->strength)
 381                 {
 382                 r = FIPS_R_INSUFFICIENT_SECURITY_STRENGTH;
 383                 goto end;
 384                 }
 385
 386         if (dctx->flags & DRBG_CUSTOM_RESEED)
 387                 dctx->generate(dctx, NULL, outlen, NULL, 0);
 388         else if (dctx->reseed_counter >= dctx->reseed_interval)
 389                 dctx->status = DRBG_STATUS_RESEED;
 390
 391         if (dctx->status == DRBG_STATUS_RESEED || prediction_resistance)
 392                 {
 393                 if (!FIPS_drbg_reseed(dctx, adin, adinlen))
 394                         {
 395                         r = FIPS_R_RESEED_ERROR;
 396                         goto end;
 397                         }
 398                 adin = NULL;
 399                 adinlen = 0;
 400                 }
 401
 402         if (!dctx->generate(dctx, out, outlen, adin, adinlen))
 403                 {
 404                 r = FIPS_R_GENERATE_ERROR;
 405                 dctx->status = DRBG_STATUS_ERROR;
 406                 goto end;
 407                 }
 408         if (!(dctx->flags & DRBG_CUSTOM_RESEED))
 409                 {
 410                 if (dctx->reseed_counter >= dctx->reseed_interval)
 411                         dctx->status = DRBG_STATUS_RESEED;
 412                 else
 413                         dctx->reseed_counter++;
 414                 }
 415
 416         end:
 417         if (r)
 418                 {
 419                 if (!(dctx->flags & DRBG_FLAG_NOERR))
 420                         FIPSerr(FIPS_F_FIPS_DRBG_GENERATE, r);
 421                 return 0;
 422                 }
 423
 424         return 1;
 425         }
 426
 427 int FIPS_drbg_uninstantiate(DRBG_CTX *dctx)
 428         {
 429         int rv;
 430         if (!dctx->uninstantiate)
 431                 rv = 1;
 432         else
 433                 rv = dctx->uninstantiate(dctx);
 434         /* Although we'd like to cleanse here we can't because we have to
 435          * test the uninstantiate really zeroes the data.
 436          */
 437         memset(&dctx->d, 0, sizeof(dctx->d));
 438         dctx->status = DRBG_STATUS_UNINITIALISED;
 439         /* If method has problems uninstantiating, return error */
 440         return rv;
 441         }
 442
 443 int FIPS_drbg_set_callbacks(DRBG_CTX *dctx,
 444         size_t (*get_entropy)(DRBG_CTX *ctx, unsigned char **pout,
 445                                 int entropy, size_t min_len, size_t max_len),
 446         void (*cleanup_entropy)(DRBG_CTX *ctx, unsigned char *out, size_t olen),
 447         size_t entropy_blocklen,
 448         size_t (*get_nonce)(DRBG_CTX *ctx, unsigned char **pout,
 449                                 int entropy, size_t min_len, size_t max_len),
 450         void (*cleanup_nonce)(DRBG_CTX *ctx, unsigned char *out, size_t olen))
 451         {
 452         if (dctx->status != DRBG_STATUS_UNINITIALISED)
 453                 return 0;
 454         dctx->entropy_blocklen = entropy_blocklen;
 455         dctx->get_entropy = get_entropy;
 456         dctx->cleanup_entropy = cleanup_entropy;
 457         dctx->get_nonce = get_nonce;
 458         dctx->cleanup_nonce = cleanup_nonce;
 459         return 1;
 460         }
 461
 462 int FIPS_drbg_set_rand_callbacks(DRBG_CTX *dctx,
 463         size_t (*get_adin)(DRBG_CTX *ctx, unsigned char **pout),
 464         void (*cleanup_adin)(DRBG_CTX *ctx, unsigned char *out, size_t olen),
 465         int (*rand_seed_cb)(DRBG_CTX *ctx, const void *buf, int num),
 466         int (*rand_add_cb)(DRBG_CTX *ctx,
 467                                 const void *buf, int num, double entropy))
 468         {
 469         if (dctx->status != DRBG_STATUS_UNINITIALISED)
 470                 return 0;
 471         dctx->get_adin = get_adin;
 472         dctx->cleanup_adin = cleanup_adin;
 473         dctx->rand_seed_cb = rand_seed_cb;
 474         dctx->rand_add_cb = rand_add_cb;
 475         return 1;
 476         }
 477
 478 void *FIPS_drbg_get_app_data(DRBG_CTX *dctx)
 479         {
 480         return dctx->app_data;
 481         }
 482
 483 void FIPS_drbg_set_app_data(DRBG_CTX *dctx, void *app_data)
 484         {
 485         dctx->app_data = app_data;
 486         }
 487
 488 size_t FIPS_drbg_get_blocklength(DRBG_CTX *dctx)
 489         {
 490         return dctx->blocklength;
 491         }
 492
 493 int FIPS_drbg_get_strength(DRBG_CTX *dctx)
 494         {
 495         return dctx->strength;
 496         }
 497
 498 void FIPS_drbg_set_check_interval(DRBG_CTX *dctx, int interval)
 499         {
 500         dctx->health_check_interval = interval;
 501         }
 502
 503 static int drbg_stick = 0;
 504
 505 void FIPS_drbg_stick(void)
 506         {
 507         drbg_stick = 1;
 508         }
 509
 510 /* Continuous DRBG utility function */
 511 int fips_drbg_cprng_test(DRBG_CTX *dctx, const unsigned char *out)
 512         {
 513         /* No CPRNG in test mode */
 514         if (dctx->flags & DRBG_FLAG_TEST)
 515                 return 1;
 516         /* Check block is valid: should never happen */
 517         if (dctx->lb_valid == 0)
 518                 {
 519                 FIPSerr(FIPS_F_FIPS_DRBG_CPRNG_TEST, FIPS_R_INTERNAL_ERROR);
 520                 fips_set_selftest_fail();
 521                 return 0;
 522                 }
 523         if (drbg_stick)
 524                 memcpy(dctx->lb, out, dctx->blocklength);
 525         /* Check against last block: fail if match */
 526         if (!memcmp(dctx->lb, out, dctx->blocklength))
 527                 {
 528                 FIPSerr(FIPS_F_FIPS_DRBG_CPRNG_TEST, FIPS_R_DRBG_STUCK);
 529                 fips_set_selftest_fail();
 530                 return 0;
 531                 }
 532         /* Save last block for next comparison */
 533         memcpy(dctx->lb, out, dctx->blocklength);
 534         return 1;
 535         }