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
  83         if (rv <= 0)
  84                 {
  85                 if (rv == -2)
  86                         FIPSerr(FIPS_F_FIPS_DRBG_INIT, FIPS_R_UNSUPPORTED_DRBG_TYPE);
  87                 else
  88                         FIPSerr(FIPS_F_FIPS_DRBG_INIT, FIPS_R_ERROR_INITIALISING_DRBG);
  89                 }
  90
  91         /* If not in test mode run selftests on DRBG of the same type */
  92
  93         if (!(dctx->flags & DRBG_FLAG_TEST))
  94                 {
  95                 DRBG_CTX tctx;
  96                 if (!fips_drbg_kat(&tctx, type, flags | DRBG_FLAG_TEST))
  97                         {
  98                         FIPSerr(FIPS_F_FIPS_DRBG_INIT, FIPS_R_SELFTEST_FAILURE);
  99                         return 0;
 100                         }
 101                 }
 102
 103         return rv;
 104         }
 105
 106 DRBG_CTX *FIPS_drbg_new(int type, unsigned int flags)
 107         {
 108         DRBG_CTX *dctx;
 109         dctx = OPENSSL_malloc(sizeof(DRBG_CTX));
 110         if (!dctx)
 111                 {
 112                 FIPSerr(FIPS_F_FIPS_DRBG_NEW, ERR_R_MALLOC_FAILURE);
 113                 return NULL;
 114                 }
 115         if (type == 0)
 116                 return dctx;
 117
 118         if (FIPS_drbg_init(dctx, type, flags) <= 0)
 119                 {
 120                 OPENSSL_free(dctx);
 121                 return NULL;
 122                 }
 123
 124         return dctx;
 125         }
 126
 127 void FIPS_drbg_free(DRBG_CTX *dctx)
 128         {
 129         if (dctx->uninstantiate)
 130                 dctx->uninstantiate(dctx);
 131         OPENSSL_cleanse(&dctx->d, sizeof(dctx->d));
 132         OPENSSL_free(dctx);
 133         }
 134
 135 static size_t fips_get_entropy(DRBG_CTX *dctx, unsigned char **pout,
 136                                 int entropy, size_t min_len, size_t max_len)
 137         {
 138         unsigned char *tout, *p;
 139         size_t bl = dctx->entropy_blocklen, rv;
 140         if (dctx->flags & DRBG_FLAG_TEST || !bl)
 141                 return dctx->get_entropy(dctx, pout, entropy, min_len, max_len);
 142         rv = dctx->get_entropy(dctx, &tout, entropy + bl,
 143                                 min_len + bl, max_len + bl);
 144         *pout = tout + bl;
 145         if (rv < (min_len + bl) || (rv % bl))
 146                 return 0;
 147         /* Compare consecutive blocks for continuous PRNG test */
 148         for (p = tout; p < tout + rv - bl; p += bl)
 149                 {
 150                 if (!memcmp(p, p + bl, bl))
 151                         {
 152                         FIPSerr(FIPS_F_FIPS_GET_ENTROPY, FIPS_R_ENTROPY_SOURCE_STUCK);
 153                         return 0;
 154                         }
 155                 }
 156         rv -= bl;
 157         if (rv > max_len)
 158                 return max_len;
 159         return rv;
 160         }
 161
 162 static void fips_cleanup_entropy(DRBG_CTX *dctx,
 163                                         unsigned char *out, size_t olen)
 164         {
 165         size_t bl;
 166         if (dctx->flags & DRBG_FLAG_TEST)
 167                 bl = 0;
 168         else
 169                 bl = dctx->entropy_blocklen;
 170         /* Call cleanup with original arguments */
 171         dctx->cleanup_entropy(dctx, out - bl, olen + bl);
 172         }
 173
 174
 175 int FIPS_drbg_instantiate(DRBG_CTX *dctx,
 176                                 const unsigned char *pers, size_t perslen)
 177         {
 178         size_t entlen = 0, noncelen = 0;
 179         unsigned char *nonce = NULL, *entropy = NULL;
 180
 181 #if 0
 182         /* Put here so error script picks them up */
 183         FIPSerr(FIPS_F_FIPS_DRBG_INSTANTIATE,
 184                                 FIPS_R_PERSONALISATION_STRING_TOO_LONG);
 185         FIPSerr(FIPS_F_FIPS_DRBG_INSTANTIATE, FIPS_R_IN_ERROR_STATE);
 186         FIPSerr(FIPS_F_FIPS_DRBG_INSTANTIATE, FIPS_R_ALREADY_INSTANTIATED);
 187         FIPSerr(FIPS_F_FIPS_DRBG_INSTANTIATE, FIPS_R_ERROR_RETRIEVING_ENTROPY);
 188         FIPSerr(FIPS_F_FIPS_DRBG_INSTANTIATE, FIPS_R_ERROR_RETRIEVING_NONCE);
 189         FIPSerr(FIPS_F_FIPS_DRBG_INSTANTIATE, FIPS_R_INSTANTIATE_ERROR);
 190 #endif
 191
 192         int r = 0;
 193
 194         if (perslen > dctx->max_pers)
 195                 {
 196                 r = FIPS_R_PERSONALISATION_STRING_TOO_LONG;
 197                 goto end;
 198                 }
 199
 200         if (dctx->status != DRBG_STATUS_UNINITIALISED)
 201                 {
 202                 if (dctx->status == DRBG_STATUS_ERROR)
 203                         r = FIPS_R_IN_ERROR_STATE;
 204                 else
 205                         r = FIPS_R_ALREADY_INSTANTIATED;
 206                 goto end;
 207                 }
 208
 209         dctx->status = DRBG_STATUS_ERROR;
 210
 211         entlen = fips_get_entropy(dctx, &entropy, dctx->strength,
 212                                 dctx->min_entropy, dctx->max_entropy);
 213
 214         if (entlen < dctx->min_entropy || entlen > dctx->max_entropy)
 215                 {
 216                 r = FIPS_R_ERROR_RETRIEVING_ENTROPY;
 217                 goto end;
 218                 }
 219
 220         if (dctx->max_nonce > 0)
 221                 {
 222                 noncelen = dctx->get_nonce(dctx, &nonce,
 223                                         dctx->strength / 2,
 224                                         dctx->min_nonce, dctx->max_nonce);
 225
 226                 if (noncelen < dctx->min_nonce || noncelen > dctx->max_nonce)
 227                         {
 228                         r = FIPS_R_ERROR_RETRIEVING_NONCE;
 229                         goto end;
 230                         }
 231
 232                 }
 233
 234         if (!dctx->instantiate(dctx,
 235                                 entropy, entlen,
 236                                 nonce, noncelen,
 237                                 pers, perslen))
 238                 {
 239                 r = FIPS_R_ERROR_INSTANTIATING_DRBG;
 240                 goto end;
 241                 }
 242
 243
 244         dctx->status = DRBG_STATUS_READY;
 245         dctx->reseed_counter = 1;
 246
 247         end:
 248
 249         if (entropy && dctx->cleanup_entropy)
 250                 fips_cleanup_entropy(dctx, entropy, entlen);
 251
 252         if (nonce && dctx->cleanup_nonce)
 253                 dctx->cleanup_nonce(dctx, nonce, noncelen);
 254
 255         if (dctx->status == DRBG_STATUS_READY)
 256                 return 1;
 257
 258         if (r && !(dctx->flags & DRBG_FLAG_NOERR))
 259                 FIPSerr(FIPS_F_FIPS_DRBG_INSTANTIATE, r);
 260
 261         return 0;
 262
 263         }
 264
 265 int FIPS_drbg_reseed(DRBG_CTX *dctx,
 266                         const unsigned char *adin, size_t adinlen)
 267         {
 268         unsigned char *entropy = NULL;
 269         size_t entlen;
 270         int r = 0;
 271
 272 #if 0
 273         FIPSerr(FIPS_F_FIPS_DRBG_RESEED, FIPS_R_NOT_INSTANTIATED);
 274         FIPSerr(FIPS_F_FIPS_DRBG_RESEED, FIPS_R_ADDITIONAL_INPUT_TOO_LONG);
 275 #endif
 276         if (dctx->status != DRBG_STATUS_READY
 277                 && dctx->status != DRBG_STATUS_RESEED)
 278                 {
 279                 if (dctx->status == DRBG_STATUS_ERROR)
 280                         r = FIPS_R_IN_ERROR_STATE;
 281                 else if(dctx->status == DRBG_STATUS_UNINITIALISED)
 282                         r = FIPS_R_NOT_INSTANTIATED;
 283                 goto end;
 284                 }
 285
 286         if (!adin)
 287                 adinlen = 0;
 288         else if (adinlen > dctx->max_adin)
 289                 {
 290                 r = FIPS_R_ADDITIONAL_INPUT_TOO_LONG;
 291                 goto end;
 292                 }
 293
 294         dctx->status = DRBG_STATUS_ERROR;
 295
 296         entlen = fips_get_entropy(dctx, &entropy, dctx->strength,
 297                                 dctx->min_entropy, dctx->max_entropy);
 298
 299         if (entlen < dctx->min_entropy || entlen > dctx->max_entropy)
 300                 {
 301                 r = FIPS_R_ERROR_RETRIEVING_ENTROPY;
 302                 goto end;
 303                 }
 304
 305         if (!dctx->reseed(dctx, entropy, entlen, adin, adinlen))
 306                 goto end;
 307
 308         dctx->status = DRBG_STATUS_READY;
 309         dctx->reseed_counter = 1;
 310         end:
 311
 312         if (entropy && dctx->cleanup_entropy)
 313                 fips_cleanup_entropy(dctx, entropy, entlen);
 314
 315         if (dctx->status == DRBG_STATUS_READY)
 316                 return 1;
 317
 318         if (r && !(dctx->flags & DRBG_FLAG_NOERR))
 319                 FIPSerr(FIPS_F_FIPS_DRBG_RESEED, r);
 320
 321         return 0;
 322         }
 323
 324 static int fips_drbg_check(DRBG_CTX *dctx)
 325         {
 326         if (dctx->flags & DRBG_FLAG_TEST)
 327                 return 1;
 328         dctx->health_check_cnt++;
 329         if (dctx->health_check_cnt >= dctx->health_check_interval)
 330                 {
 331                 DRBG_CTX tctx;
 332                 if (!fips_drbg_kat(&tctx, dctx->type,
 333                                                 dctx->flags | DRBG_FLAG_TEST))
 334                         {
 335                         FIPSerr(FIPS_F_FIPS_DRBG_CHECK, FIPS_R_SELFTEST_FAILURE);
 336                         return 0;
 337                         }
 338                 dctx->health_check_cnt = 0;
 339                 }
 340         return 1;
 341         }
 342
 343 int FIPS_drbg_generate(DRBG_CTX *dctx, unsigned char *out, size_t outlen,
 344                         int strength, int prediction_resistance,
 345                         const unsigned char *adin, size_t adinlen)
 346         {
 347         int r = 0;
 348
 349         if (!fips_drbg_check(dctx))
 350                 return 0;
 351
 352         if (dctx->status != DRBG_STATUS_READY
 353                 && dctx->status != DRBG_STATUS_RESEED)
 354                 {
 355                 if (dctx->status == DRBG_STATUS_ERROR)
 356                         r = FIPS_R_IN_ERROR_STATE;
 357                 else if(dctx->status == DRBG_STATUS_UNINITIALISED)
 358                         r = FIPS_R_NOT_INSTANTIATED;
 359                 goto end;
 360                 }
 361
 362         if (outlen > dctx->max_request)
 363                 {
 364                 r = FIPS_R_REQUEST_TOO_LARGE_FOR_DRBG;
 365                 return 0;
 366                 }
 367
 368         if (strength > dctx->strength)
 369                 {
 370                 r = FIPS_R_INSUFFICIENT_SECURITY_STRENGTH;
 371                 goto end;
 372                 }
 373
 374         if (dctx->status == DRBG_STATUS_RESEED || prediction_resistance)
 375                 {
 376                 if (!FIPS_drbg_reseed(dctx, adin, adinlen))
 377                         {
 378                         r = FIPS_R_RESEED_ERROR;
 379                         goto end;
 380                         }
 381                 adin = NULL;
 382                 adinlen = 0;
 383                 }
 384
 385         if (!dctx->generate(dctx, out, outlen, adin, adinlen))
 386                 {
 387                 r = FIPS_R_GENERATE_ERROR;
 388                 dctx->status = DRBG_STATUS_ERROR;
 389                 goto end;
 390                 }
 391         if (dctx->reseed_counter >= dctx->reseed_interval)
 392                 dctx->status = DRBG_STATUS_RESEED;
 393         else
 394                 dctx->reseed_counter++;
 395
 396         end:
 397         if (r)
 398                 {
 399                 if (!(dctx->flags & DRBG_FLAG_NOERR))
 400                         FIPSerr(FIPS_F_FIPS_DRBG_GENERATE, r);
 401                 return 0;
 402                 }
 403
 404         return 1;
 405         }
 406
 407 int FIPS_drbg_uninstantiate(DRBG_CTX *dctx)
 408         {
 409         int rv;
 410         if (!dctx->uninstantiate)
 411                 rv = 1;
 412         else
 413                 rv = dctx->uninstantiate(dctx);
 414         /* Although we'd like to cleanse here we can't because we have to
 415          * test the uninstantiate really zeroes the data.
 416          */
 417         memset(&dctx->d, 0, sizeof(dctx->d));
 418         dctx->status = DRBG_STATUS_UNINITIALISED;
 419         /* If method has problems uninstantiating, return error */
 420         return rv;
 421         }
 422
 423 int FIPS_drbg_set_callbacks(DRBG_CTX *dctx,
 424         size_t (*get_entropy)(DRBG_CTX *ctx, unsigned char **pout,
 425                                 int entropy, size_t min_len, size_t max_len),
 426         void (*cleanup_entropy)(DRBG_CTX *ctx, unsigned char *out, size_t olen),
 427         size_t entropy_blocklen,
 428         size_t (*get_nonce)(DRBG_CTX *ctx, unsigned char **pout,
 429                                 int entropy, size_t min_len, size_t max_len),
 430         void (*cleanup_nonce)(DRBG_CTX *ctx, unsigned char *out, size_t olen))
 431         {
 432         if (dctx->status != DRBG_STATUS_UNINITIALISED)
 433                 return 0;
 434         dctx->entropy_blocklen = entropy_blocklen;
 435         dctx->get_entropy = get_entropy;
 436         dctx->cleanup_entropy = cleanup_entropy;
 437         dctx->get_nonce = get_nonce;
 438         dctx->cleanup_nonce = cleanup_nonce;
 439         return 1;
 440         }
 441
 442 int FIPS_drbg_set_rand_callbacks(DRBG_CTX *dctx,
 443         size_t (*get_adin)(DRBG_CTX *ctx, unsigned char **pout),
 444         void (*cleanup_adin)(DRBG_CTX *ctx, unsigned char *out, size_t olen),
 445         int (*rand_seed_cb)(DRBG_CTX *ctx, const void *buf, int num),
 446         int (*rand_add_cb)(DRBG_CTX *ctx,
 447                                 const void *buf, int num, double entropy))
 448         {
 449         if (dctx->status != DRBG_STATUS_UNINITIALISED)
 450                 return 0;
 451         dctx->get_adin = get_adin;
 452         dctx->cleanup_adin = cleanup_adin;
 453         dctx->rand_seed_cb = rand_seed_cb;
 454         dctx->rand_add_cb = rand_add_cb;
 455         return 1;
 456         }
 457
 458 void *FIPS_drbg_get_app_data(DRBG_CTX *dctx)
 459         {
 460         return dctx->app_data;
 461         }
 462
 463 void FIPS_drbg_set_app_data(DRBG_CTX *dctx, void *app_data)
 464         {
 465         dctx->app_data = app_data;
 466         }
 467
 468 size_t FIPS_drbg_get_blocklength(DRBG_CTX *dctx)
 469         {
 470         return dctx->blocklength;
 471         }
 472
 473 int FIPS_drbg_get_strength(DRBG_CTX *dctx)
 474         {
 475         return dctx->strength;
 476         }
 477
 478 void FIPS_drbg_set_check_interval(DRBG_CTX *dctx, int interval)
 479         {
 480         dctx->health_check_interval = interval;
 481         }
 482
 483 static int drbg_stick = 0;
 484
 485 void FIPS_drbg_stick(void)
 486         {
 487         drbg_stick = 1;
 488         }
 489
 490 /* Continuous DRBG utility function */
 491 int fips_drbg_cprng_test(DRBG_CTX *dctx, const unsigned char *out)
 492         {
 493         /* No CPRNG in test mode */
 494         if (dctx->flags & DRBG_FLAG_TEST)
 495                 return 1;
 496         /* Check block is valid: should never happen */
 497         if (dctx->lb_valid == 0)
 498                 {
 499                 FIPSerr(FIPS_F_FIPS_DRBG_CPRNG_TEST, FIPS_R_INTERNAL_ERROR);
 500                 fips_set_selftest_fail();
 501                 return 0;
 502                 }
 503         if (drbg_stick)
 504                 memcpy(dctx->lb, out, dctx->blocklength);
 505         /* Check against last block: fail if match */
 506         if (!memcmp(dctx->lb, out, dctx->blocklength))
 507                 {
 508                 FIPSerr(FIPS_F_FIPS_DRBG_CPRNG_TEST, FIPS_R_DRBG_STUCK);
 509                 fips_set_selftest_fail();
 510                 return 0;
 511                 }
 512         /* Save last block for next comparison */
 513         memcpy(dctx->lb, out, dctx->blocklength);
 514         return 1;
 515         }