fips/rand/fips_drbg_lib.c

   1 /* Written by Dr Stephen N Henson (steve@openssl.org) for the OpenSSL
   2  * project.
   3  */
   4 /* ====================================================================
   5  * Copyright (c) 2011 The OpenSSL Project.  All rights reserved.
   6  *
   7  * Redistribution and use in source and binary forms, with or without
   8  * modification, are permitted provided that the following conditions
   9  * are met:
  10  *
  11  * 1. Redistributions of source code must retain the above copyright
  12  *    notice, this list of conditions and the following disclaimer.
  13  *
  14  * 2. Redistributions in binary form must reproduce the above copyright
  15  *    notice, this list of conditions and the following disclaimer in
  16  *    the documentation and/or other materials provided with the
  17  *    distribution.
  18  *
  19  * 3. All advertising materials mentioning features or use of this
  20  *    software must display the following acknowledgment:
  21  *    "This product includes software developed by the OpenSSL Project
  22  *    for use in the OpenSSL Toolkit. (http://www.OpenSSL.org/)"
  23  *
  24  * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
  25  *    endorse or promote products derived from this software without
  26  *    prior written permission. For written permission, please contact
  27  *    licensing@OpenSSL.org.
  28  *
  29  * 5. Products derived from this software may not be called "OpenSSL"
  30  *    nor may "OpenSSL" appear in their names without prior written
  31  *    permission of the OpenSSL Project.
  32  *
  33  * 6. Redistributions of any form whatsoever must retain the following
  34  *    acknowledgment:
  35  *    "This product includes software developed by the OpenSSL Project
  36  *    for use in the OpenSSL Toolkit (http://www.OpenSSL.org/)"
  37  *
  38  * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
  39  * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  40  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  41  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE OpenSSL PROJECT OR
  42  * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  43  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  44  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  45  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  46  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
  47  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  48  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
  49  * OF THE POSSIBILITY OF SUCH DAMAGE.
  50  * ====================================================================
  51  */
  52
  53 #define OPENSSL_FIPSAPI
  54
  55 #include <string.h>
  56 #include <openssl/crypto.h>
  57 #include <openssl/err.h>
  58 #include <openssl/fips_rand.h>
  59 #include "fips_rand_lcl.h"
  60
  61 /* Support framework for SP800-90 DRBGs */
  62
  63 int FIPS_drbg_init(DRBG_CTX *dctx, int type, unsigned int flags)
  64         {
  65         int rv;
  66         memset(dctx, 0, sizeof(DRBG_CTX));
  67         dctx->status = DRBG_STATUS_UNINITIALISED;
  68         dctx->xflags = flags;
  69         dctx->type = type;
  70
  71         dctx->iflags = 0;
  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->xflags & DRBG_FLAG_TEST))
  96                 {
  97                 if (!FIPS_drbg_health_check(dctx))
  98                         {
  99                         FIPSerr(FIPS_F_FIPS_DRBG_INIT, FIPS_R_SELFTEST_FAILURE);
 100                         return 0;
 101                         }
 102                 }
 103
 104         return rv;
 105         }
 106
 107 DRBG_CTX *FIPS_drbg_new(int type, unsigned int flags)
 108         {
 109         DRBG_CTX *dctx;
 110         dctx = OPENSSL_malloc(sizeof(DRBG_CTX));
 111         if (!dctx)
 112                 {
 113                 FIPSerr(FIPS_F_FIPS_DRBG_NEW, ERR_R_MALLOC_FAILURE);
 114                 return NULL;
 115                 }
 116
 117         if (type == 0)
 118                 {
 119                 memset(dctx, 0, sizeof(DRBG_CTX));
 120                 dctx->type = 0;
 121                 dctx->status = DRBG_STATUS_UNINITIALISED;
 122                 return dctx;
 123                 }
 124
 125         if (FIPS_drbg_init(dctx, type, flags) <= 0)
 126                 {
 127                 OPENSSL_free(dctx);
 128                 return NULL;
 129                 }
 130
 131         return dctx;
 132         }
 133
 134 void FIPS_drbg_free(DRBG_CTX *dctx)
 135         {
 136         if (dctx->uninstantiate)
 137                 dctx->uninstantiate(dctx);
 138         /* Don't free up default DRBG */
 139         if (dctx == FIPS_get_default_drbg())
 140                 {
 141                 memset(dctx, 0, sizeof(DRBG_CTX));
 142                 dctx->type = 0;
 143                 dctx->status = DRBG_STATUS_UNINITIALISED;
 144                 }
 145         else
 146                 {
 147                 OPENSSL_cleanse(&dctx->d, sizeof(dctx->d));
 148                 OPENSSL_free(dctx);
 149                 }
 150         }
 151
 152 static size_t fips_get_entropy(DRBG_CTX *dctx, unsigned char **pout,
 153                                 int entropy, size_t min_len, size_t max_len)
 154         {
 155         unsigned char *tout, *p;
 156         size_t bl = dctx->entropy_blocklen, rv;
 157         if (dctx->xflags & DRBG_FLAG_TEST || !bl)
 158                 return dctx->get_entropy(dctx, pout, entropy, min_len, max_len);
 159         rv = dctx->get_entropy(dctx, &tout, entropy + bl,
 160                                 min_len + bl, max_len + bl);
 161         *pout = tout + bl;
 162         if (rv < (min_len + bl) || (rv % bl))
 163                 return 0;
 164         /* Compare consecutive blocks for continuous PRNG test */
 165         for (p = tout; p < tout + rv - bl; p += bl)
 166                 {
 167                 if (!memcmp(p, p + bl, bl))
 168                         {
 169                         FIPSerr(FIPS_F_FIPS_GET_ENTROPY, FIPS_R_ENTROPY_SOURCE_STUCK);
 170                         return 0;
 171                         }
 172                 }
 173         rv -= bl;
 174         if (rv > max_len)
 175                 return max_len;
 176         return rv;
 177         }
 178
 179 static void fips_cleanup_entropy(DRBG_CTX *dctx,
 180                                         unsigned char *out, size_t olen)
 181         {
 182         size_t bl;
 183         if (dctx->xflags & DRBG_FLAG_TEST)
 184                 bl = 0;
 185         else
 186                 bl = dctx->entropy_blocklen;
 187         /* Call cleanup with original arguments */
 188         dctx->cleanup_entropy(dctx, out - bl, olen + bl);
 189         }
 190
 191
 192 int FIPS_drbg_instantiate(DRBG_CTX *dctx,
 193                                 const unsigned char *pers, size_t perslen)
 194         {
 195         size_t entlen = 0, noncelen = 0;
 196         unsigned char *nonce = NULL, *entropy = NULL;
 197
 198 #if 0
 199         /* Put here so error script picks them up */
 200         FIPSerr(FIPS_F_FIPS_DRBG_INSTANTIATE,
 201                                 FIPS_R_PERSONALISATION_STRING_TOO_LONG);
 202         FIPSerr(FIPS_F_FIPS_DRBG_INSTANTIATE, FIPS_R_IN_ERROR_STATE);
 203         FIPSerr(FIPS_F_FIPS_DRBG_INSTANTIATE, FIPS_R_ALREADY_INSTANTIATED);
 204         FIPSerr(FIPS_F_FIPS_DRBG_INSTANTIATE, FIPS_R_ERROR_RETRIEVING_ENTROPY);
 205         FIPSerr(FIPS_F_FIPS_DRBG_INSTANTIATE, FIPS_R_ERROR_RETRIEVING_NONCE);
 206         FIPSerr(FIPS_F_FIPS_DRBG_INSTANTIATE, FIPS_R_INSTANTIATE_ERROR);
 207         FIPSerr(FIPS_F_FIPS_DRBG_INSTANTIATE, FIPS_R_DRBG_NOT_INITIALISED);
 208 #endif
 209
 210         int r = 0;
 211
 212         if (perslen > dctx->max_pers)
 213                 {
 214                 r = FIPS_R_PERSONALISATION_STRING_TOO_LONG;
 215                 goto end;
 216                 }
 217
 218         if (!dctx->instantiate)
 219                 {
 220                 r = FIPS_R_DRBG_NOT_INITIALISED;
 221                 goto end;
 222                 }
 223
 224         if (dctx->status != DRBG_STATUS_UNINITIALISED)
 225                 {
 226                 if (dctx->status == DRBG_STATUS_ERROR)
 227                         r = FIPS_R_IN_ERROR_STATE;
 228                 else
 229                         r = FIPS_R_ALREADY_INSTANTIATED;
 230                 goto end;
 231                 }
 232
 233         dctx->status = DRBG_STATUS_ERROR;
 234
 235         entlen = fips_get_entropy(dctx, &entropy, dctx->strength,
 236                                 dctx->min_entropy, dctx->max_entropy);
 237
 238         if (entlen < dctx->min_entropy || entlen > dctx->max_entropy)
 239                 {
 240                 r = FIPS_R_ERROR_RETRIEVING_ENTROPY;
 241                 goto end;
 242                 }
 243
 244         if (dctx->max_nonce > 0)
 245                 {
 246                 noncelen = dctx->get_nonce(dctx, &nonce,
 247                                         dctx->strength / 2,
 248                                         dctx->min_nonce, dctx->max_nonce);
 249
 250                 if (noncelen < dctx->min_nonce || noncelen > dctx->max_nonce)
 251                         {
 252                         r = FIPS_R_ERROR_RETRIEVING_NONCE;
 253                         goto end;
 254                         }
 255
 256                 }
 257
 258         if (!dctx->instantiate(dctx,
 259                                 entropy, entlen,
 260                                 nonce, noncelen,
 261                                 pers, perslen))
 262                 {
 263                 r = FIPS_R_ERROR_INSTANTIATING_DRBG;
 264                 goto end;
 265                 }
 266
 267
 268         dctx->status = DRBG_STATUS_READY;
 269         if (!(dctx->iflags & DRBG_CUSTOM_RESEED))
 270                 dctx->reseed_counter = 1;
 271
 272         end:
 273
 274         if (entropy && dctx->cleanup_entropy)
 275                 fips_cleanup_entropy(dctx, entropy, entlen);
 276
 277         if (nonce && dctx->cleanup_nonce)
 278                 dctx->cleanup_nonce(dctx, nonce, noncelen);
 279
 280         if (dctx->status == DRBG_STATUS_READY)
 281                 return 1;
 282
 283         if (r && !(dctx->iflags & DRBG_FLAG_NOERR))
 284                 FIPSerr(FIPS_F_FIPS_DRBG_INSTANTIATE, r);
 285
 286         return 0;
 287
 288         }
 289
 290 static int drbg_reseed(DRBG_CTX *dctx,
 291                         const unsigned char *adin, size_t adinlen, int hcheck)
 292         {
 293         unsigned char *entropy = NULL;
 294         size_t entlen = 0;
 295         int r = 0;
 296
 297 #if 0
 298         FIPSerr(FIPS_F_DRBG_RESEED, FIPS_R_NOT_INSTANTIATED);
 299         FIPSerr(FIPS_F_DRBG_RESEED, FIPS_R_ADDITIONAL_INPUT_TOO_LONG);
 300 #endif
 301         if (dctx->status != DRBG_STATUS_READY
 302                 && dctx->status != DRBG_STATUS_RESEED)
 303                 {
 304                 if (dctx->status == DRBG_STATUS_ERROR)
 305                         r = FIPS_R_IN_ERROR_STATE;
 306                 else if(dctx->status == DRBG_STATUS_UNINITIALISED)
 307                         r = FIPS_R_NOT_INSTANTIATED;
 308                 goto end;
 309                 }
 310
 311         if (!adin)
 312                 adinlen = 0;
 313         else if (adinlen > dctx->max_adin)
 314                 {
 315                 r = FIPS_R_ADDITIONAL_INPUT_TOO_LONG;
 316                 goto end;
 317                 }
 318
 319         dctx->status = DRBG_STATUS_ERROR;
 320         /* Peform health check on all reseed operations if not a prediction
 321          * resistance request and not in test mode.
 322          */
 323         if (hcheck && !(dctx->xflags & DRBG_FLAG_TEST))
 324                 {
 325                 if (!FIPS_drbg_health_check(dctx))
 326                         {
 327                         r = FIPS_R_SELFTEST_FAILURE;
 328                         goto end;
 329                         }
 330                 }
 331
 332         entlen = fips_get_entropy(dctx, &entropy, dctx->strength,
 333                                 dctx->min_entropy, dctx->max_entropy);
 334
 335         if (entlen < dctx->min_entropy || entlen > dctx->max_entropy)
 336                 {
 337                 r = FIPS_R_ERROR_RETRIEVING_ENTROPY;
 338                 goto end;
 339                 }
 340
 341         if (!dctx->reseed(dctx, entropy, entlen, adin, adinlen))
 342                 goto end;
 343
 344         dctx->status = DRBG_STATUS_READY;
 345         if (!(dctx->iflags & DRBG_CUSTOM_RESEED))
 346                 dctx->reseed_counter = 1;
 347         end:
 348
 349         if (entropy && dctx->cleanup_entropy)
 350                 fips_cleanup_entropy(dctx, entropy, entlen);
 351
 352         if (dctx->status == DRBG_STATUS_READY)
 353                 return 1;
 354
 355         if (r && !(dctx->iflags & DRBG_FLAG_NOERR))
 356                 FIPSerr(FIPS_F_DRBG_RESEED, r);
 357
 358         return 0;
 359         }
 360
 361 int FIPS_drbg_reseed(DRBG_CTX *dctx,
 362                         const unsigned char *adin, size_t adinlen)
 363         {
 364         return drbg_reseed(dctx, adin, adinlen, 1);
 365         }
 366
 367 static int fips_drbg_check(DRBG_CTX *dctx)
 368         {
 369         if (dctx->xflags & DRBG_FLAG_TEST)
 370                 return 1;
 371         dctx->health_check_cnt++;
 372         if (dctx->health_check_cnt >= dctx->health_check_interval)
 373                 {
 374                 if (!FIPS_drbg_health_check(dctx))
 375                         {
 376                         FIPSerr(FIPS_F_FIPS_DRBG_CHECK, FIPS_R_SELFTEST_FAILURE);
 377                         return 0;
 378                         }
 379                 }
 380         return 1;
 381         }
 382
 383 int FIPS_drbg_generate(DRBG_CTX *dctx, unsigned char *out, size_t outlen,
 384                         int prediction_resistance,
 385                         const unsigned char *adin, size_t adinlen)
 386         {
 387         int r = 0;
 388
 389         if (!fips_drbg_check(dctx))
 390                 return 0;
 391
 392         if (dctx->status != DRBG_STATUS_READY
 393                 && dctx->status != DRBG_STATUS_RESEED)
 394                 {
 395                 if (dctx->status == DRBG_STATUS_ERROR)
 396                         r = FIPS_R_IN_ERROR_STATE;
 397                 else if(dctx->status == DRBG_STATUS_UNINITIALISED)
 398                         r = FIPS_R_NOT_INSTANTIATED;
 399                 goto end;
 400                 }
 401
 402         if (outlen > dctx->max_request)
 403                 {
 404                 r = FIPS_R_REQUEST_TOO_LARGE_FOR_DRBG;
 405                 return 0;
 406                 }
 407
 408         if (adinlen > dctx->max_adin)
 409                 {
 410                 r = FIPS_R_ADDITIONAL_INPUT_TOO_LONG;
 411                 goto end;
 412                 }
 413
 414         if (dctx->iflags & DRBG_CUSTOM_RESEED)
 415                 dctx->generate(dctx, NULL, outlen, NULL, 0);
 416         else if (dctx->reseed_counter >= dctx->reseed_interval)
 417                 dctx->status = DRBG_STATUS_RESEED;
 418
 419         if (dctx->status == DRBG_STATUS_RESEED || prediction_resistance)
 420                 {
 421                 /* If prediction resistance request don't do health check */
 422                 int hcheck = prediction_resistance ? 0 : 1;
 423
 424                 if (!drbg_reseed(dctx, adin, adinlen, hcheck))
 425                         {
 426                         r = FIPS_R_RESEED_ERROR;
 427                         goto end;
 428                         }
 429                 adin = NULL;
 430                 adinlen = 0;
 431                 }
 432
 433         if (!dctx->generate(dctx, out, outlen, adin, adinlen))
 434                 {
 435                 r = FIPS_R_GENERATE_ERROR;
 436                 dctx->status = DRBG_STATUS_ERROR;
 437                 goto end;
 438                 }
 439         if (!(dctx->iflags & DRBG_CUSTOM_RESEED))
 440                 {
 441                 if (dctx->reseed_counter >= dctx->reseed_interval)
 442                         dctx->status = DRBG_STATUS_RESEED;
 443                 else
 444                         dctx->reseed_counter++;
 445                 }
 446
 447         end:
 448         if (r)
 449                 {
 450                 if (!(dctx->iflags & DRBG_FLAG_NOERR))
 451                         FIPSerr(FIPS_F_FIPS_DRBG_GENERATE, r);
 452                 return 0;
 453                 }
 454
 455         return 1;
 456         }
 457
 458 int FIPS_drbg_uninstantiate(DRBG_CTX *dctx)
 459         {
 460         int rv;
 461         if (!dctx->uninstantiate)
 462                 rv = 1;
 463         else
 464                 rv = dctx->uninstantiate(dctx);
 465         /* Although we'd like to cleanse here we can't because we have to
 466          * test the uninstantiate really zeroes the data.
 467          */
 468         memset(&dctx->d, 0, sizeof(dctx->d));
 469         dctx->status = DRBG_STATUS_UNINITIALISED;
 470         /* If method has problems uninstantiating, return error */
 471         return rv;
 472         }
 473
 474 int FIPS_drbg_set_callbacks(DRBG_CTX *dctx,
 475         size_t (*get_entropy)(DRBG_CTX *ctx, unsigned char **pout,
 476                                 int entropy, size_t min_len, size_t max_len),
 477         void (*cleanup_entropy)(DRBG_CTX *ctx, unsigned char *out, size_t olen),
 478         size_t entropy_blocklen,
 479         size_t (*get_nonce)(DRBG_CTX *ctx, unsigned char **pout,
 480                                 int entropy, size_t min_len, size_t max_len),
 481         void (*cleanup_nonce)(DRBG_CTX *ctx, unsigned char *out, size_t olen))
 482         {
 483         if (dctx->status != DRBG_STATUS_UNINITIALISED)
 484                 return 0;
 485         dctx->entropy_blocklen = entropy_blocklen;
 486         dctx->get_entropy = get_entropy;
 487         dctx->cleanup_entropy = cleanup_entropy;
 488         dctx->get_nonce = get_nonce;
 489         dctx->cleanup_nonce = cleanup_nonce;
 490         return 1;
 491         }
 492
 493 int FIPS_drbg_set_rand_callbacks(DRBG_CTX *dctx,
 494         size_t (*get_adin)(DRBG_CTX *ctx, unsigned char **pout),
 495         void (*cleanup_adin)(DRBG_CTX *ctx, unsigned char *out, size_t olen),
 496         int (*rand_seed_cb)(DRBG_CTX *ctx, const void *buf, int num),
 497         int (*rand_add_cb)(DRBG_CTX *ctx,
 498                                 const void *buf, int num, double entropy))
 499         {
 500         if (dctx->status != DRBG_STATUS_UNINITIALISED)
 501                 return 0;
 502         dctx->get_adin = get_adin;
 503         dctx->cleanup_adin = cleanup_adin;
 504         dctx->rand_seed_cb = rand_seed_cb;
 505         dctx->rand_add_cb = rand_add_cb;
 506         return 1;
 507         }
 508
 509 void *FIPS_drbg_get_app_data(DRBG_CTX *dctx)
 510         {
 511         return dctx->app_data;
 512         }
 513
 514 void FIPS_drbg_set_app_data(DRBG_CTX *dctx, void *app_data)
 515         {
 516         dctx->app_data = app_data;
 517         }
 518
 519 size_t FIPS_drbg_get_blocklength(DRBG_CTX *dctx)
 520         {
 521         return dctx->blocklength;
 522         }
 523
 524 int FIPS_drbg_get_strength(DRBG_CTX *dctx)
 525         {
 526         return dctx->strength;
 527         }
 528
 529 void FIPS_drbg_set_check_interval(DRBG_CTX *dctx, int interval)
 530         {
 531         dctx->health_check_interval = interval;
 532         }
 533
 534 void FIPS_drbg_set_reseed_interval(DRBG_CTX *dctx, int interval)
 535         {
 536         dctx->reseed_interval = interval;
 537         }
 538
 539 static int drbg_stick = 0;
 540
 541 void FIPS_drbg_stick(void)
 542         {
 543         drbg_stick = 1;
 544         }
 545
 546 /* Continuous DRBG utility function */
 547 int fips_drbg_cprng_test(DRBG_CTX *dctx, const unsigned char *out)
 548         {
 549         /* No CPRNG in test mode */
 550         if (dctx->xflags & DRBG_FLAG_TEST)
 551                 return 1;
 552         /* Check block is valid: should never happen */
 553         if (dctx->lb_valid == 0)
 554                 {
 555                 FIPSerr(FIPS_F_FIPS_DRBG_CPRNG_TEST, FIPS_R_INTERNAL_ERROR);
 556                 fips_set_selftest_fail();
 557                 return 0;
 558                 }
 559         if (drbg_stick)
 560                 memcpy(dctx->lb, out, dctx->blocklength);
 561         /* Check against last block: fail if match */
 562         if (!memcmp(dctx->lb, out, dctx->blocklength))
 563                 {
 564                 FIPSerr(FIPS_F_FIPS_DRBG_CPRNG_TEST, FIPS_R_DRBG_STUCK);
 565                 fips_set_selftest_fail();
 566                 return 0;
 567                 }
 568         /* Save last block for next comparison */
 569         memcpy(dctx->lb, out, dctx->blocklength);
 570         return 1;
 571         }