crypto/dsa/dsa_gen.c

   1 /* crypto/dsa/dsa_gen.c */
   2 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
   3  * All rights reserved.
   4  *
   5  * This package is an SSL implementation written
   6  * by Eric Young (eay@cryptsoft.com).
   7  * The implementation was written so as to conform with Netscapes SSL.
   8  *
   9  * This library is free for commercial and non-commercial use as long as
  10  * the following conditions are aheared to.  The following conditions
  11  * apply to all code found in this distribution, be it the RC4, RSA,
  12  * lhash, DES, etc., code; not just the SSL code.  The SSL documentation
  13  * included with this distribution is covered by the same copyright terms
  14  * except that the holder is Tim Hudson (tjh@cryptsoft.com).
  15  *
  16  * Copyright remains Eric Young's, and as such any Copyright notices in
  17  * the code are not to be removed.
  18  * If this package is used in a product, Eric Young should be given attribution
  19  * as the author of the parts of the library used.
  20  * This can be in the form of a textual message at program startup or
  21  * in documentation (online or textual) provided with the package.
  22  *
  23  * Redistribution and use in source and binary forms, with or without
  24  * modification, are permitted provided that the following conditions
  25  * are met:
  26  * 1. Redistributions of source code must retain the copyright
  27  *    notice, this list of conditions and the following disclaimer.
  28  * 2. Redistributions in binary form must reproduce the above copyright
  29  *    notice, this list of conditions and the following disclaimer in the
  30  *    documentation and/or other materials provided with the distribution.
  31  * 3. All advertising materials mentioning features or use of this software
  32  *    must display the following acknowledgement:
  33  *    "This product includes cryptographic software written by
  34  *     Eric Young (eay@cryptsoft.com)"
  35  *    The word 'cryptographic' can be left out if the rouines from the library
  36  *    being used are not cryptographic related :-).
  37  * 4. If you include any Windows specific code (or a derivative thereof) from
  38  *    the apps directory (application code) you must include an acknowledgement:
  39  *    "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
  40  *
  41  * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
  42  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  43  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  44  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  45  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  46  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  47  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  48  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  49  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  50  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  51  * SUCH DAMAGE.
  52  *
  53  * The licence and distribution terms for any publically available version or
  54  * derivative of this code cannot be changed.  i.e. this code cannot simply be
  55  * copied and put under another distribution licence
  56  * [including the GNU Public Licence.]
  57  */
  58
  59 #undef GENUINE_DSA
  60
  61 #ifdef GENUINE_DSA
  62 /* Parameter generation follows the original release of FIPS PUB 186,
  63  * Appendix 2.2 (i.e. use SHA as defined in FIPS PUB 180) */
  64 #define HASH    EVP_sha()
  65 #else
  66 /* Parameter generation follows the updated Appendix 2.2 for FIPS PUB 186,
  67  * also Appendix 2.2 of FIPS PUB 186-1 (i.e. use SHA as defined in
  68  * FIPS PUB 180-1) */
  69 #define HASH    EVP_sha1()
  70 #endif
  71
  72 #include <openssl/opensslconf.h> /* To see if OPENSSL_NO_SHA is defined */
  73
  74 #ifndef OPENSSL_NO_SHA
  75
  76 #define OPENSSL_FIPSAPI
  77
  78 #include <stdio.h>
  79 #include "cryptlib.h"
  80 #include <openssl/evp.h>
  81 #include <openssl/bn.h>
  82 #include <openssl/rand.h>
  83 #include <openssl/sha.h>
  84
  85 #include "dsa_locl.h"
  86
  87 int DSA_generate_parameters_ex(DSA *ret, int bits,
  88                 const unsigned char *seed_in, int seed_len,
  89                 int *counter_ret, unsigned long *h_ret, BN_GENCB *cb)
  90         {
  91         if(ret->meth->dsa_paramgen)
  92                 return ret->meth->dsa_paramgen(ret, bits, seed_in, seed_len,
  93                                 counter_ret, h_ret, cb);
  94         else
  95                 {
  96                 const EVP_MD *evpmd;
  97                 size_t qbits = bits >= 2048 ? 256 : 160;
  98
  99                 if (bits >= 2048)
 100                         {
 101                         qbits = 256;
 102                         evpmd = EVP_sha256();
 103                         }
 104                 else
 105                         {
 106                         qbits = 160;
 107                         evpmd = EVP_sha1();
 108                         }
 109
 110                 return dsa_builtin_paramgen(ret, bits, qbits, evpmd,
 111                         seed_in, seed_len, NULL, counter_ret, h_ret, cb);
 112                 }
 113         }
 114
 115 int dsa_builtin_paramgen(DSA *ret, size_t bits, size_t qbits,
 116         const EVP_MD *evpmd, const unsigned char *seed_in, size_t seed_len,
 117         unsigned char *seed_out,
 118         int *counter_ret, unsigned long *h_ret, BN_GENCB *cb)
 119         {
 120         int ok=0;
 121         unsigned char seed[SHA256_DIGEST_LENGTH];
 122         unsigned char md[SHA256_DIGEST_LENGTH];
 123         unsigned char buf[SHA256_DIGEST_LENGTH],buf2[SHA256_DIGEST_LENGTH];
 124         BIGNUM *r0,*W,*X,*c,*test;
 125         BIGNUM *g=NULL,*q=NULL,*p=NULL;
 126         BN_MONT_CTX *mont=NULL;
 127         int i, k, n=0, m=0, qsize = qbits >> 3;
 128         int counter=0;
 129         int r=0;
 130         BN_CTX *ctx=NULL;
 131         unsigned int h=2;
 132
 133         if (qsize != SHA_DIGEST_LENGTH && qsize != SHA224_DIGEST_LENGTH &&
 134             qsize != SHA256_DIGEST_LENGTH)
 135                 /* invalid q size */
 136                 return 0;
 137
 138         if (evpmd == NULL)
 139                 /* use SHA1 as default */
 140                 evpmd = EVP_sha1();
 141
 142         if (bits < 512)
 143                 bits = 512;
 144
 145         bits = (bits+63)/64*64;
 146
 147         /* NB: seed_len == 0 is special case: copy generated seed to
 148          * seed_in if it is not NULL.
 149          */
 150         if (seed_len && (seed_len < (size_t)qsize))
 151                 seed_in = NULL;         /* seed buffer too small -- ignore */
 152         if (seed_len > (size_t)qsize)
 153                 seed_len = qsize;       /* App. 2.2 of FIPS PUB 186 allows larger SEED,
 154                                          * but our internal buffers are restricted to 160 bits*/
 155         if (seed_in != NULL)
 156                 memcpy(seed, seed_in, seed_len);
 157
 158         if ((ctx=BN_CTX_new()) == NULL)
 159                 goto err;
 160
 161         if ((mont=BN_MONT_CTX_new()) == NULL)
 162                 goto err;
 163
 164         BN_CTX_start(ctx);
 165         r0 = BN_CTX_get(ctx);
 166         g = BN_CTX_get(ctx);
 167         W = BN_CTX_get(ctx);
 168         q = BN_CTX_get(ctx);
 169         X = BN_CTX_get(ctx);
 170         c = BN_CTX_get(ctx);
 171         p = BN_CTX_get(ctx);
 172         test = BN_CTX_get(ctx);
 173
 174         if (!BN_lshift(test,BN_value_one(),bits-1))
 175                 goto err;
 176
 177         for (;;)
 178                 {
 179                 for (;;) /* find q */
 180                         {
 181                         int seed_is_random;
 182
 183                         /* step 1 */
 184                         if(!BN_GENCB_call(cb, 0, m++))
 185                                 goto err;
 186
 187                         if (!seed_len)
 188                                 {
 189                                 if (RAND_pseudo_bytes(seed, qsize) < 0)
 190                                         goto err;
 191                                 seed_is_random = 1;
 192                                 }
 193                         else
 194                                 {
 195                                 seed_is_random = 0;
 196                                 seed_len=0; /* use random seed if 'seed_in' turns out to be bad*/
 197                                 }
 198                         memcpy(buf , seed, qsize);
 199                         memcpy(buf2, seed, qsize);
 200                         /* precompute "SEED + 1" for step 7: */
 201                         for (i = qsize-1; i >= 0; i--)
 202                                 {
 203                                 buf[i]++;
 204                                 if (buf[i] != 0)
 205                                         break;
 206                                 }
 207
 208                         /* step 2 */
 209                         if (!EVP_Digest(seed, qsize, md,   NULL, evpmd, NULL))
 210                                 goto err;
 211                         if (!EVP_Digest(buf,  qsize, buf2, NULL, evpmd, NULL))
 212                                 goto err;
 213                         for (i = 0; i < qsize; i++)
 214                                 md[i]^=buf2[i];
 215
 216                         /* step 3 */
 217                         md[0] |= 0x80;
 218                         md[qsize-1] |= 0x01;
 219                         if (!BN_bin2bn(md, qsize, q))
 220                                 goto err;
 221
 222                         /* step 4 */
 223                         r = BN_is_prime_fasttest_ex(q, DSS_prime_checks, ctx,
 224                                         seed_is_random, cb);
 225                         if (r > 0)
 226                                 break;
 227                         if (r != 0)
 228                                 goto err;
 229
 230                         /* do a callback call */
 231                         /* step 5 */
 232                         }
 233
 234                 if(!BN_GENCB_call(cb, 2, 0)) goto err;
 235                 if(!BN_GENCB_call(cb, 3, 0)) goto err;
 236
 237                 /* step 6 */
 238                 counter=0;
 239                 /* "offset = 2" */
 240
 241                 n=(bits-1)/160;
 242
 243                 for (;;)
 244                         {
 245                         if ((counter != 0) && !BN_GENCB_call(cb, 0, counter))
 246                                 goto err;
 247
 248                         /* step 7 */
 249                         BN_zero(W);
 250                         /* now 'buf' contains "SEED + offset - 1" */
 251                         for (k=0; k<=n; k++)
 252                                 {
 253                                 /* obtain "SEED + offset + k" by incrementing: */
 254                                 for (i = qsize-1; i >= 0; i--)
 255                                         {
 256                                         buf[i]++;
 257                                         if (buf[i] != 0)
 258                                                 break;
 259                                         }
 260
 261                                 if (!EVP_Digest(buf, qsize, md ,NULL, evpmd,
 262                                                                         NULL))
 263                                         goto err;
 264
 265                                 /* step 8 */
 266                                 if (!BN_bin2bn(md, qsize, r0))
 267                                         goto err;
 268                                 if (!BN_lshift(r0,r0,(qsize << 3)*k)) goto err;
 269                                 if (!BN_add(W,W,r0)) goto err;
 270                                 }
 271
 272                         /* more of step 8 */
 273                         if (!BN_mask_bits(W,bits-1)) goto err;
 274                         if (!BN_copy(X,W)) goto err;
 275                         if (!BN_add(X,X,test)) goto err;
 276
 277                         /* step 9 */
 278                         if (!BN_lshift1(r0,q)) goto err;
 279                         if (!BN_mod(c,X,r0,ctx)) goto err;
 280                         if (!BN_sub(r0,c,BN_value_one())) goto err;
 281                         if (!BN_sub(p,X,r0)) goto err;
 282
 283                         /* step 10 */
 284                         if (BN_cmp(p,test) >= 0)
 285                                 {
 286                                 /* step 11 */
 287                                 r = BN_is_prime_fasttest_ex(p, DSS_prime_checks,
 288                                                 ctx, 1, cb);
 289                                 if (r > 0)
 290                                                 goto end; /* found it */
 291                                 if (r != 0)
 292                                         goto err;
 293                                 }
 294
 295                         /* step 13 */
 296                         counter++;
 297                         /* "offset = offset + n + 1" */
 298
 299                         /* step 14 */
 300                         if (counter >= 4096) break;
 301                         }
 302                 }
 303 end:
 304         if(!BN_GENCB_call(cb, 2, 1))
 305                 goto err;
 306
 307         /* We now need to generate g */
 308         /* Set r0=(p-1)/q */
 309         if (!BN_sub(test,p,BN_value_one())) goto err;
 310         if (!BN_div(r0,NULL,test,q,ctx)) goto err;
 311
 312         if (!BN_set_word(test,h)) goto err;
 313         if (!BN_MONT_CTX_set(mont,p,ctx)) goto err;
 314
 315         for (;;)
 316                 {
 317                 /* g=test^r0%p */
 318                 if (!BN_mod_exp_mont(g,test,r0,p,ctx,mont)) goto err;
 319                 if (!BN_is_one(g)) break;
 320                 if (!BN_add(test,test,BN_value_one())) goto err;
 321                 h++;
 322                 }
 323
 324         if(!BN_GENCB_call(cb, 3, 1))
 325                 goto err;
 326
 327         ok=1;
 328 err:
 329         if (ok)
 330                 {
 331                 if(ret->p) BN_free(ret->p);
 332                 if(ret->q) BN_free(ret->q);
 333                 if(ret->g) BN_free(ret->g);
 334                 ret->p=BN_dup(p);
 335                 ret->q=BN_dup(q);
 336                 ret->g=BN_dup(g);
 337                 if (ret->p == NULL || ret->q == NULL || ret->g == NULL)
 338                         {
 339                         ok=0;
 340                         goto err;
 341                         }
 342                 if (counter_ret != NULL) *counter_ret=counter;
 343                 if (h_ret != NULL) *h_ret=h;
 344                 if (seed_out)
 345                         memcpy(seed_out, seed, qsize);
 346                 }
 347         if(ctx)
 348                 {
 349                 BN_CTX_end(ctx);
 350                 BN_CTX_free(ctx);
 351                 }
 352         if (mont != NULL) BN_MONT_CTX_free(mont);
 353         return ok;
 354         }
 355
 356 /* This is a parameter generation algorithm for the DSA2 algorithm as
 357  * described in FIPS 186-3.
 358  */
 359
 360 int dsa_builtin_paramgen2(DSA *ret, size_t L, size_t N,
 361         const EVP_MD *evpmd, const unsigned char *seed_in, size_t seed_len,
 362         int idx, unsigned char *seed_out,
 363         int *counter_ret, unsigned long *h_ret, BN_GENCB *cb)
 364         {
 365         int ok=-1;
 366         unsigned char *seed = NULL, *seed_tmp = NULL;
 367         unsigned char md[EVP_MAX_MD_SIZE];
 368         int mdsize;
 369         BIGNUM *r0,*W,*X,*c,*test;
 370         BIGNUM *g=NULL,*q=NULL,*p=NULL;
 371         BN_MONT_CTX *mont=NULL;
 372         int i, k, n=0, m=0, qsize = N >> 3;
 373         int counter=0;
 374         int r=0;
 375         BN_CTX *ctx=NULL;
 376         EVP_MD_CTX mctx;
 377         unsigned int h=2;
 378
 379         EVP_MD_CTX_init(&mctx);
 380
 381         if (evpmd == NULL)
 382                 {
 383                 if (N == 160)
 384                         evpmd = EVP_sha1();
 385                 else if (N == 224)
 386                         evpmd = EVP_sha224();
 387                 else
 388                         evpmd = EVP_sha256();
 389                 }
 390
 391         mdsize = M_EVP_MD_size(evpmd);
 392         /* If unverificable g generation only don't need seed */
 393         if (!ret->p || !ret->q || idx >= 0)
 394                 {
 395                 if (seed_len == 0)
 396                         seed_len = mdsize;
 397
 398                 seed = OPENSSL_malloc(seed_len);
 399
 400                 if (seed_out)
 401                         seed_tmp = seed_out;
 402                 else
 403                         seed_tmp = OPENSSL_malloc(seed_len);
 404
 405                 if (!seed || !seed_tmp)
 406                         goto err;
 407
 408                 if (seed_in)
 409                         memcpy(seed, seed_in, seed_len);
 410
 411                 }
 412
 413         if ((ctx=BN_CTX_new()) == NULL)
 414                 goto err;
 415
 416         if ((mont=BN_MONT_CTX_new()) == NULL)
 417                 goto err;
 418
 419         BN_CTX_start(ctx);
 420         r0 = BN_CTX_get(ctx);
 421         g = BN_CTX_get(ctx);
 422         W = BN_CTX_get(ctx);
 423         X = BN_CTX_get(ctx);
 424         c = BN_CTX_get(ctx);
 425         test = BN_CTX_get(ctx);
 426
 427         /* if p, q already supplied generate g only */
 428         if (ret->p && ret->q)
 429                 {
 430                 p = ret->p;
 431                 q = ret->q;
 432                 if (idx >= 0)
 433                         memcpy(seed_tmp, seed, seed_len);
 434                 goto g_only;
 435                 }
 436         else
 437                 {
 438                 p = BN_CTX_get(ctx);
 439                 q = BN_CTX_get(ctx);
 440                 }
 441
 442         if (!BN_lshift(test,BN_value_one(),L-1))
 443                 goto err;
 444         for (;;)
 445                 {
 446                 for (;;) /* find q */
 447                         {
 448                         unsigned char *pmd;
 449                         /* step 1 */
 450                         if(!BN_GENCB_call(cb, 0, m++))
 451                                 goto err;
 452
 453                         if (!seed_in)
 454                                 {
 455                                 if (RAND_pseudo_bytes(seed, seed_len) < 0)
 456                                         goto err;
 457                                 }
 458                         /* step 2 */
 459                         if (!EVP_Digest(seed, seed_len, md, NULL, evpmd, NULL))
 460                                 goto err;
 461                         /* Take least significant bits of md */
 462                         if (mdsize > qsize)
 463                                 pmd = md + mdsize - qsize;
 464                         else
 465                                 pmd = md;
 466
 467                         if (mdsize < qsize)
 468                                 memset(md + mdsize, 0, qsize - mdsize);
 469
 470                         /* step 3 */
 471                         pmd[0] |= 0x80;
 472                         pmd[qsize-1] |= 0x01;
 473                         if (!BN_bin2bn(pmd, qsize, q))
 474                                 goto err;
 475
 476                         /* step 4 */
 477                         r = BN_is_prime_fasttest_ex(q, DSS_prime_checks, ctx,
 478                                         seed_in ? 1 : 0, cb);
 479                         if (r > 0)
 480                                 break;
 481                         if (r != 0)
 482                                 goto err;
 483                         /* Provided seed didn't produce a prime: error */
 484                         if (seed_in)
 485                                 {
 486                                 ok = 0;
 487                                 DSAerr(DSA_F_DSA_BUILTIN_PARAMGEN2, DSA_R_Q_NOT_PRIME);
 488                                 goto err;
 489                                 }
 490
 491                         /* do a callback call */
 492                         /* step 5 */
 493                         }
 494                 /* Copy seed to seed_out before we mess with it */
 495                 if (seed_out)
 496                         memcpy(seed_out, seed, seed_len);
 497
 498                 if(!BN_GENCB_call(cb, 2, 0)) goto err;
 499                 if(!BN_GENCB_call(cb, 3, 0)) goto err;
 500
 501                 /* step 6 */
 502                 counter=0;
 503                 /* "offset = 1" */
 504
 505                 n=(L-1)/(mdsize << 3);
 506
 507                 for (;;)
 508                         {
 509                         if ((counter != 0) && !BN_GENCB_call(cb, 0, counter))
 510                                 goto err;
 511
 512                         /* step 7 */
 513                         BN_zero(W);
 514                         /* now 'buf' contains "SEED + offset - 1" */
 515                         for (k=0; k<=n; k++)
 516                                 {
 517                                 /* obtain "SEED + offset + k" by incrementing: */
 518                                 for (i = seed_len-1; i >= 0; i--)
 519                                         {
 520                                         seed[i]++;
 521                                         if (seed[i] != 0)
 522                                                 break;
 523                                         }
 524
 525                                 if (!EVP_Digest(seed, seed_len, md ,NULL, evpmd,
 526                                                                         NULL))
 527                                         goto err;
 528
 529                                 /* step 8 */
 530                                 if (!BN_bin2bn(md, mdsize, r0))
 531                                         goto err;
 532                                 if (!BN_lshift(r0,r0,(mdsize << 3)*k)) goto err;
 533                                 if (!BN_add(W,W,r0)) goto err;
 534                                 }
 535
 536                         /* more of step 8 */
 537                         if (!BN_mask_bits(W,L-1)) goto err;
 538                         if (!BN_copy(X,W)) goto err;
 539                         if (!BN_add(X,X,test)) goto err;
 540
 541                         /* step 9 */
 542                         if (!BN_lshift1(r0,q)) goto err;
 543                         if (!BN_mod(c,X,r0,ctx)) goto err;
 544                         if (!BN_sub(r0,c,BN_value_one())) goto err;
 545                         if (!BN_sub(p,X,r0)) goto err;
 546
 547                         /* step 10 */
 548                         if (BN_cmp(p,test) >= 0)
 549                                 {
 550                                 /* step 11 */
 551                                 r = BN_is_prime_fasttest_ex(p, DSS_prime_checks,
 552                                                 ctx, 1, cb);
 553                                 if (r > 0)
 554                                                 goto end; /* found it */
 555                                 if (r != 0)
 556                                         goto err;
 557                                 }
 558
 559                         /* step 13 */
 560                         counter++;
 561                         /* "offset = offset + n + 1" */
 562
 563                         /* step 14 */
 564                         if (counter >= (int)(4 * L)) break;
 565                         }
 566                 if (seed_in)
 567                         {
 568                         ok = 0;
 569                         DSAerr(DSA_F_DSA_BUILTIN_PARAMGEN2, DSA_R_INVALID_PARAMETERS);
 570                         goto err;
 571                         }
 572                 }
 573 end:
 574         if(!BN_GENCB_call(cb, 2, 1))
 575                 goto err;
 576
 577         g_only:
 578
 579         /* We now need to generate g */
 580         /* Set r0=(p-1)/q */
 581         if (!BN_sub(test,p,BN_value_one())) goto err;
 582         if (!BN_div(r0,NULL,test,q,ctx)) goto err;
 583
 584         if (idx < 0)
 585                 {
 586                 if (!BN_set_word(test,h))
 587                         goto err;
 588                 }
 589         else
 590                 h = 1;
 591         if (!BN_MONT_CTX_set(mont,p,ctx)) goto err;
 592
 593         for (;;)
 594                 {
 595                 static const unsigned char ggen[4] = {0x67,0x67,0x65,0x6e};
 596                 if (idx >= 0)
 597                         {
 598                         md[0] = idx & 0xff;
 599                         md[1] = (h >> 8) & 0xff;
 600                         md[2] = h & 0xff;
 601                         if (!EVP_DigestInit_ex(&mctx, evpmd, NULL))
 602                                 goto err;
 603                         if (!EVP_DigestUpdate(&mctx, seed_tmp, seed_len))
 604                                 goto err;
 605                         if (!EVP_DigestUpdate(&mctx, ggen, sizeof(ggen)))
 606                                 goto err;
 607                         if (!EVP_DigestUpdate(&mctx, md, 3))
 608                                 goto err;
 609                         if (!EVP_DigestFinal_ex(&mctx, md, NULL))
 610                                 goto err;
 611                         if (!BN_bin2bn(md, mdsize, test))
 612                                 goto err;
 613                         }
 614                 /* g=test^r0%p */
 615                 if (!BN_mod_exp_mont(g,test,r0,p,ctx,mont)) goto err;
 616                 if (!BN_is_one(g)) break;
 617                 if (idx < 0 && !BN_add(test,test,BN_value_one())) goto err;
 618                 h++;
 619                 if ( idx >= 0 && h > 0xffff)
 620                         goto err;
 621                 }
 622
 623         if(!BN_GENCB_call(cb, 3, 1))
 624                 goto err;
 625
 626         ok=1;
 627 err:
 628         if (ok == 1)
 629                 {
 630                 if (p != ret->p)
 631                         {
 632                         if(ret->p) BN_free(ret->p);
 633                         ret->p=BN_dup(p);
 634                         }
 635                 if (q != ret->q)
 636                         {
 637                         if(ret->q) BN_free(ret->q);
 638                         ret->q=BN_dup(q);
 639                         }
 640                 if(ret->g) BN_free(ret->g);
 641                 ret->g=BN_dup(g);
 642                 if (ret->p == NULL || ret->q == NULL || ret->g == NULL)
 643                         {
 644                         ok=-1;
 645                         goto err;
 646                         }
 647                 if (counter_ret != NULL) *counter_ret=counter;
 648                 if (h_ret != NULL) *h_ret=h;
 649                 }
 650         if (seed)
 651                 OPENSSL_free(seed);
 652         if (seed_out != seed_tmp)
 653                 OPENSSL_free(seed_tmp);
 654         if(ctx)
 655                 {
 656                 BN_CTX_end(ctx);
 657                 BN_CTX_free(ctx);
 658                 }
 659         if (mont != NULL) BN_MONT_CTX_free(mont);
 660         EVP_MD_CTX_cleanup(&mctx);
 661         return ok;
 662         }
 663
 664 int dsa_paramgen_check_g(DSA *dsa)
 665         {
 666         BN_CTX *ctx;
 667         BIGNUM *tmp;
 668         BN_MONT_CTX *mont = NULL;
 669         int rv = -1;
 670         ctx = BN_CTX_new();
 671         if (!ctx)
 672                 return -1;
 673         BN_CTX_start(ctx);
 674         if (BN_cmp(dsa->g, BN_value_one()) <= 0)
 675                 return 0;
 676         if (BN_cmp(dsa->g, dsa->p) >= 0)
 677                 return 0;
 678         tmp = BN_CTX_get(ctx);
 679         if (!tmp)
 680                 goto err;
 681         if ((mont=BN_MONT_CTX_new()) == NULL)
 682                 goto err;
 683         if (!BN_MONT_CTX_set(mont,dsa->p,ctx))
 684                 goto err;
 685         /* Work out g^q mod p */
 686         if (!BN_mod_exp_mont(tmp,dsa->g,dsa->q, dsa->p, ctx, mont))
 687                 goto err;
 688         if (!BN_cmp(tmp, BN_value_one()))
 689                 rv = 1;
 690         else
 691                 rv = 0;
 692         err:
 693         BN_CTX_end(ctx);
 694         if (mont)
 695                 BN_MONT_CTX_free(mont);
 696         BN_CTX_free(ctx);
 697         return rv;
 698
 699         }
 700
 701 #endif