dsa_gen.c revision 340704
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/* 63 * Parameter generation follows the original release of FIPS PUB 186, 64 * Appendix 2.2 (i.e. use SHA as defined in FIPS PUB 180) 65 */ 66# define HASH EVP_sha() 67#else 68/* 69 * Parameter generation follows the updated Appendix 2.2 for FIPS PUB 186, 70 * also Appendix 2.2 of FIPS PUB 186-1 (i.e. use SHA as defined in FIPS PUB 71 * 180-1) 72 */ 73# define HASH EVP_sha1() 74#endif 75 76#include <openssl/opensslconf.h> /* To see if OPENSSL_NO_SHA is defined */ 77 78#ifndef OPENSSL_NO_SHA 79 80# include <stdio.h> 81# include "cryptlib.h" 82# include <openssl/evp.h> 83# include <openssl/bn.h> 84# include <openssl/rand.h> 85# include <openssl/sha.h> 86# include "dsa_locl.h" 87 88# ifdef OPENSSL_FIPS 89/* Workaround bug in prototype */ 90# define fips_dsa_builtin_paramgen2 fips_dsa_paramgen_bad 91# include <openssl/fips.h> 92# endif 93 94int DSA_generate_parameters_ex(DSA *ret, int bits, 95 const unsigned char *seed_in, int seed_len, 96 int *counter_ret, unsigned long *h_ret, 97 BN_GENCB *cb) 98{ 99# ifdef OPENSSL_FIPS 100 if (FIPS_mode() && !(ret->meth->flags & DSA_FLAG_FIPS_METHOD) 101 && !(ret->flags & DSA_FLAG_NON_FIPS_ALLOW)) { 102 DSAerr(DSA_F_DSA_GENERATE_PARAMETERS_EX, DSA_R_NON_FIPS_DSA_METHOD); 103 return 0; 104 } 105# endif 106 if (ret->meth->dsa_paramgen) 107 return ret->meth->dsa_paramgen(ret, bits, seed_in, seed_len, 108 counter_ret, h_ret, cb); 109# ifdef OPENSSL_FIPS 110 else if (FIPS_mode()) { 111 return FIPS_dsa_generate_parameters_ex(ret, bits, 112 seed_in, seed_len, 113 counter_ret, h_ret, cb); 114 } 115# endif 116 else { 117 const EVP_MD *evpmd = bits >= 2048 ? EVP_sha256() : EVP_sha1(); 118 size_t qbits = EVP_MD_size(evpmd) * 8; 119 120 return dsa_builtin_paramgen(ret, bits, qbits, evpmd, 121 seed_in, seed_len, NULL, counter_ret, 122 h_ret, cb); 123 } 124} 125 126int dsa_builtin_paramgen(DSA *ret, size_t bits, size_t qbits, 127 const EVP_MD *evpmd, const unsigned char *seed_in, 128 size_t seed_len, unsigned char *seed_out, 129 int *counter_ret, unsigned long *h_ret, BN_GENCB *cb) 130{ 131 int ok = 0; 132 unsigned char seed[SHA256_DIGEST_LENGTH]; 133 unsigned char md[SHA256_DIGEST_LENGTH]; 134 unsigned char buf[SHA256_DIGEST_LENGTH], buf2[SHA256_DIGEST_LENGTH]; 135 BIGNUM *r0, *W, *X, *c, *test; 136 BIGNUM *g = NULL, *q = NULL, *p = NULL; 137 BN_MONT_CTX *mont = NULL; 138 int i, k, n = 0, m = 0, qsize = qbits >> 3; 139 int counter = 0; 140 int r = 0; 141 BN_CTX *ctx = NULL; 142 unsigned int h = 2; 143 144 if (qsize != SHA_DIGEST_LENGTH && qsize != SHA224_DIGEST_LENGTH && 145 qsize != SHA256_DIGEST_LENGTH) 146 /* invalid q size */ 147 return 0; 148 149 if (evpmd == NULL) { 150 if (qsize == SHA_DIGEST_LENGTH) 151 evpmd = EVP_sha1(); 152 else if (qsize == SHA224_DIGEST_LENGTH) 153 evpmd = EVP_sha224(); 154 else 155 evpmd = EVP_sha256(); 156 } else { 157 qsize = EVP_MD_size(evpmd); 158 } 159 160 if (bits < 512) 161 bits = 512; 162 163 bits = (bits + 63) / 64 * 64; 164 165 /* 166 * NB: seed_len == 0 is special case: copy generated seed to seed_in if 167 * it is not NULL. 168 */ 169 if (seed_len && (seed_len < (size_t)qsize)) 170 seed_in = NULL; /* seed buffer too small -- ignore */ 171 if (seed_len > (size_t)qsize) 172 seed_len = qsize; /* App. 2.2 of FIPS PUB 186 allows larger 173 * SEED, but our internal buffers are 174 * restricted to 160 bits */ 175 if (seed_in != NULL) 176 memcpy(seed, seed_in, seed_len); 177 178 if ((mont = BN_MONT_CTX_new()) == NULL) 179 goto err; 180 181 if ((ctx = BN_CTX_new()) == NULL) 182 goto err; 183 184 BN_CTX_start(ctx); 185 186 r0 = BN_CTX_get(ctx); 187 g = BN_CTX_get(ctx); 188 W = BN_CTX_get(ctx); 189 q = BN_CTX_get(ctx); 190 X = BN_CTX_get(ctx); 191 c = BN_CTX_get(ctx); 192 p = BN_CTX_get(ctx); 193 test = BN_CTX_get(ctx); 194 195 if (test == NULL) 196 goto err; 197 198 if (!BN_lshift(test, BN_value_one(), bits - 1)) 199 goto err; 200 201 for (;;) { 202 for (;;) { /* find q */ 203 int seed_is_random; 204 205 /* step 1 */ 206 if (!BN_GENCB_call(cb, 0, m++)) 207 goto err; 208 209 if (!seed_len || !seed_in) { 210 if (RAND_bytes(seed, qsize) <= 0) 211 goto err; 212 seed_is_random = 1; 213 } else { 214 seed_is_random = 0; 215 seed_len = 0; /* use random seed if 'seed_in' turns out to 216 * be bad */ 217 } 218 memcpy(buf, seed, qsize); 219 memcpy(buf2, seed, qsize); 220 /* precompute "SEED + 1" for step 7: */ 221 for (i = qsize - 1; i >= 0; i--) { 222 buf[i]++; 223 if (buf[i] != 0) 224 break; 225 } 226 227 /* step 2 */ 228 if (!EVP_Digest(seed, qsize, md, NULL, evpmd, NULL)) 229 goto err; 230 if (!EVP_Digest(buf, qsize, buf2, NULL, evpmd, NULL)) 231 goto err; 232 for (i = 0; i < qsize; i++) 233 md[i] ^= buf2[i]; 234 235 /* step 3 */ 236 md[0] |= 0x80; 237 md[qsize - 1] |= 0x01; 238 if (!BN_bin2bn(md, qsize, q)) 239 goto err; 240 241 /* step 4 */ 242 r = BN_is_prime_fasttest_ex(q, DSS_prime_checks, ctx, 243 seed_is_random, cb); 244 if (r > 0) 245 break; 246 if (r != 0) 247 goto err; 248 249 /* do a callback call */ 250 /* step 5 */ 251 } 252 253 if (!BN_GENCB_call(cb, 2, 0)) 254 goto err; 255 if (!BN_GENCB_call(cb, 3, 0)) 256 goto err; 257 258 /* step 6 */ 259 counter = 0; 260 /* "offset = 2" */ 261 262 n = (bits - 1) / 160; 263 264 for (;;) { 265 if ((counter != 0) && !BN_GENCB_call(cb, 0, counter)) 266 goto err; 267 268 /* step 7 */ 269 BN_zero(W); 270 /* now 'buf' contains "SEED + offset - 1" */ 271 for (k = 0; k <= n; k++) { 272 /* 273 * obtain "SEED + offset + k" by incrementing: 274 */ 275 for (i = qsize - 1; i >= 0; i--) { 276 buf[i]++; 277 if (buf[i] != 0) 278 break; 279 } 280 281 if (!EVP_Digest(buf, qsize, md, NULL, evpmd, NULL)) 282 goto err; 283 284 /* step 8 */ 285 if (!BN_bin2bn(md, qsize, r0)) 286 goto err; 287 if (!BN_lshift(r0, r0, (qsize << 3) * k)) 288 goto err; 289 if (!BN_add(W, W, r0)) 290 goto err; 291 } 292 293 /* more of step 8 */ 294 if (!BN_mask_bits(W, bits - 1)) 295 goto err; 296 if (!BN_copy(X, W)) 297 goto err; 298 if (!BN_add(X, X, test)) 299 goto err; 300 301 /* step 9 */ 302 if (!BN_lshift1(r0, q)) 303 goto err; 304 if (!BN_mod(c, X, r0, ctx)) 305 goto err; 306 if (!BN_sub(r0, c, BN_value_one())) 307 goto err; 308 if (!BN_sub(p, X, r0)) 309 goto err; 310 311 /* step 10 */ 312 if (BN_cmp(p, test) >= 0) { 313 /* step 11 */ 314 r = BN_is_prime_fasttest_ex(p, DSS_prime_checks, ctx, 1, cb); 315 if (r > 0) 316 goto end; /* found it */ 317 if (r != 0) 318 goto err; 319 } 320 321 /* step 13 */ 322 counter++; 323 /* "offset = offset + n + 1" */ 324 325 /* step 14 */ 326 if (counter >= 4096) 327 break; 328 } 329 } 330 end: 331 if (!BN_GENCB_call(cb, 2, 1)) 332 goto err; 333 334 /* We now need to generate g */ 335 /* Set r0=(p-1)/q */ 336 if (!BN_sub(test, p, BN_value_one())) 337 goto err; 338 if (!BN_div(r0, NULL, test, q, ctx)) 339 goto err; 340 341 if (!BN_set_word(test, h)) 342 goto err; 343 if (!BN_MONT_CTX_set(mont, p, ctx)) 344 goto err; 345 346 for (;;) { 347 /* g=test^r0%p */ 348 if (!BN_mod_exp_mont(g, test, r0, p, ctx, mont)) 349 goto err; 350 if (!BN_is_one(g)) 351 break; 352 if (!BN_add(test, test, BN_value_one())) 353 goto err; 354 h++; 355 } 356 357 if (!BN_GENCB_call(cb, 3, 1)) 358 goto err; 359 360 ok = 1; 361 err: 362 if (ok) { 363 if (ret->p) 364 BN_free(ret->p); 365 if (ret->q) 366 BN_free(ret->q); 367 if (ret->g) 368 BN_free(ret->g); 369 ret->p = BN_dup(p); 370 ret->q = BN_dup(q); 371 ret->g = BN_dup(g); 372 if (ret->p == NULL || ret->q == NULL || ret->g == NULL) { 373 ok = 0; 374 goto err; 375 } 376 if (counter_ret != NULL) 377 *counter_ret = counter; 378 if (h_ret != NULL) 379 *h_ret = h; 380 if (seed_out) 381 memcpy(seed_out, seed, qsize); 382 } 383 if (ctx) { 384 BN_CTX_end(ctx); 385 BN_CTX_free(ctx); 386 } 387 if (mont != NULL) 388 BN_MONT_CTX_free(mont); 389 return ok; 390} 391 392# ifdef OPENSSL_FIPS 393# undef fips_dsa_builtin_paramgen2 394extern int fips_dsa_builtin_paramgen2(DSA *ret, size_t L, size_t N, 395 const EVP_MD *evpmd, 396 const unsigned char *seed_in, 397 size_t seed_len, int idx, 398 unsigned char *seed_out, 399 int *counter_ret, unsigned long *h_ret, 400 BN_GENCB *cb); 401# endif 402 403/* 404 * This is a parameter generation algorithm for the DSA2 algorithm as 405 * described in FIPS 186-3. 406 */ 407 408int dsa_builtin_paramgen2(DSA *ret, size_t L, size_t N, 409 const EVP_MD *evpmd, const unsigned char *seed_in, 410 size_t seed_len, int idx, unsigned char *seed_out, 411 int *counter_ret, unsigned long *h_ret, 412 BN_GENCB *cb) 413{ 414 int ok = -1; 415 unsigned char *seed = NULL, *seed_tmp = NULL; 416 unsigned char md[EVP_MAX_MD_SIZE]; 417 int mdsize; 418 BIGNUM *r0, *W, *X, *c, *test; 419 BIGNUM *g = NULL, *q = NULL, *p = NULL; 420 BN_MONT_CTX *mont = NULL; 421 int i, k, n = 0, m = 0, qsize = N >> 3; 422 int counter = 0; 423 int r = 0; 424 BN_CTX *ctx = NULL; 425 EVP_MD_CTX mctx; 426 unsigned int h = 2; 427 428# ifdef OPENSSL_FIPS 429 430 if (FIPS_mode()) 431 return fips_dsa_builtin_paramgen2(ret, L, N, evpmd, 432 seed_in, seed_len, idx, 433 seed_out, counter_ret, h_ret, cb); 434# endif 435 436 EVP_MD_CTX_init(&mctx); 437 438 /* make sure L > N, otherwise we'll get trapped in an infinite loop */ 439 if (L <= N) { 440 DSAerr(DSA_F_DSA_BUILTIN_PARAMGEN2, DSA_R_INVALID_PARAMETERS); 441 goto err; 442 } 443 444 if (evpmd == NULL) { 445 if (N == 160) 446 evpmd = EVP_sha1(); 447 else if (N == 224) 448 evpmd = EVP_sha224(); 449 else 450 evpmd = EVP_sha256(); 451 } 452 453 mdsize = EVP_MD_size(evpmd); 454 /* If unverificable g generation only don't need seed */ 455 if (!ret->p || !ret->q || idx >= 0) { 456 if (seed_len == 0) 457 seed_len = mdsize; 458 459 seed = OPENSSL_malloc(seed_len); 460 461 if (seed_out) 462 seed_tmp = seed_out; 463 else 464 seed_tmp = OPENSSL_malloc(seed_len); 465 466 if (!seed || !seed_tmp) 467 goto err; 468 469 if (seed_in) 470 memcpy(seed, seed_in, seed_len); 471 472 } 473 474 if ((ctx = BN_CTX_new()) == NULL) 475 goto err; 476 477 if ((mont = BN_MONT_CTX_new()) == NULL) 478 goto err; 479 480 BN_CTX_start(ctx); 481 r0 = BN_CTX_get(ctx); 482 g = BN_CTX_get(ctx); 483 W = BN_CTX_get(ctx); 484 X = BN_CTX_get(ctx); 485 c = BN_CTX_get(ctx); 486 test = BN_CTX_get(ctx); 487 488 /* if p, q already supplied generate g only */ 489 if (ret->p && ret->q) { 490 p = ret->p; 491 q = ret->q; 492 if (idx >= 0) 493 memcpy(seed_tmp, seed, seed_len); 494 goto g_only; 495 } else { 496 p = BN_CTX_get(ctx); 497 q = BN_CTX_get(ctx); 498 if (q == NULL) 499 goto err; 500 } 501 502 if (!BN_lshift(test, BN_value_one(), L - 1)) 503 goto err; 504 for (;;) { 505 for (;;) { /* find q */ 506 unsigned char *pmd; 507 /* step 1 */ 508 if (!BN_GENCB_call(cb, 0, m++)) 509 goto err; 510 511 if (!seed_in) { 512 if (RAND_bytes(seed, seed_len) <= 0) 513 goto err; 514 } 515 /* step 2 */ 516 if (!EVP_Digest(seed, seed_len, md, NULL, evpmd, NULL)) 517 goto err; 518 /* Take least significant bits of md */ 519 if (mdsize > qsize) 520 pmd = md + mdsize - qsize; 521 else 522 pmd = md; 523 524 if (mdsize < qsize) 525 memset(md + mdsize, 0, qsize - mdsize); 526 527 /* step 3 */ 528 pmd[0] |= 0x80; 529 pmd[qsize - 1] |= 0x01; 530 if (!BN_bin2bn(pmd, qsize, q)) 531 goto err; 532 533 /* step 4 */ 534 r = BN_is_prime_fasttest_ex(q, DSS_prime_checks, ctx, 535 seed_in ? 1 : 0, cb); 536 if (r > 0) 537 break; 538 if (r != 0) 539 goto err; 540 /* Provided seed didn't produce a prime: error */ 541 if (seed_in) { 542 ok = 0; 543 DSAerr(DSA_F_DSA_BUILTIN_PARAMGEN2, DSA_R_Q_NOT_PRIME); 544 goto err; 545 } 546 547 /* do a callback call */ 548 /* step 5 */ 549 } 550 /* Copy seed to seed_out before we mess with it */ 551 if (seed_out) 552 memcpy(seed_out, seed, seed_len); 553 554 if (!BN_GENCB_call(cb, 2, 0)) 555 goto err; 556 if (!BN_GENCB_call(cb, 3, 0)) 557 goto err; 558 559 /* step 6 */ 560 counter = 0; 561 /* "offset = 1" */ 562 563 n = (L - 1) / (mdsize << 3); 564 565 for (;;) { 566 if ((counter != 0) && !BN_GENCB_call(cb, 0, counter)) 567 goto err; 568 569 /* step 7 */ 570 BN_zero(W); 571 /* now 'buf' contains "SEED + offset - 1" */ 572 for (k = 0; k <= n; k++) { 573 /* 574 * obtain "SEED + offset + k" by incrementing: 575 */ 576 for (i = seed_len - 1; i >= 0; i--) { 577 seed[i]++; 578 if (seed[i] != 0) 579 break; 580 } 581 582 if (!EVP_Digest(seed, seed_len, md, NULL, evpmd, NULL)) 583 goto err; 584 585 /* step 8 */ 586 if (!BN_bin2bn(md, mdsize, r0)) 587 goto err; 588 if (!BN_lshift(r0, r0, (mdsize << 3) * k)) 589 goto err; 590 if (!BN_add(W, W, r0)) 591 goto err; 592 } 593 594 /* more of step 8 */ 595 if (!BN_mask_bits(W, L - 1)) 596 goto err; 597 if (!BN_copy(X, W)) 598 goto err; 599 if (!BN_add(X, X, test)) 600 goto err; 601 602 /* step 9 */ 603 if (!BN_lshift1(r0, q)) 604 goto err; 605 if (!BN_mod(c, X, r0, ctx)) 606 goto err; 607 if (!BN_sub(r0, c, BN_value_one())) 608 goto err; 609 if (!BN_sub(p, X, r0)) 610 goto err; 611 612 /* step 10 */ 613 if (BN_cmp(p, test) >= 0) { 614 /* step 11 */ 615 r = BN_is_prime_fasttest_ex(p, DSS_prime_checks, ctx, 1, cb); 616 if (r > 0) 617 goto end; /* found it */ 618 if (r != 0) 619 goto err; 620 } 621 622 /* step 13 */ 623 counter++; 624 /* "offset = offset + n + 1" */ 625 626 /* step 14 */ 627 if (counter >= (int)(4 * L)) 628 break; 629 } 630 if (seed_in) { 631 ok = 0; 632 DSAerr(DSA_F_DSA_BUILTIN_PARAMGEN2, DSA_R_INVALID_PARAMETERS); 633 goto err; 634 } 635 } 636 end: 637 if (!BN_GENCB_call(cb, 2, 1)) 638 goto err; 639 640 g_only: 641 642 /* We now need to generate g */ 643 /* Set r0=(p-1)/q */ 644 if (!BN_sub(test, p, BN_value_one())) 645 goto err; 646 if (!BN_div(r0, NULL, test, q, ctx)) 647 goto err; 648 649 if (idx < 0) { 650 if (!BN_set_word(test, h)) 651 goto err; 652 } else 653 h = 1; 654 if (!BN_MONT_CTX_set(mont, p, ctx)) 655 goto err; 656 657 for (;;) { 658 static const unsigned char ggen[4] = { 0x67, 0x67, 0x65, 0x6e }; 659 if (idx >= 0) { 660 md[0] = idx & 0xff; 661 md[1] = (h >> 8) & 0xff; 662 md[2] = h & 0xff; 663 if (!EVP_DigestInit_ex(&mctx, evpmd, NULL)) 664 goto err; 665 if (!EVP_DigestUpdate(&mctx, seed_tmp, seed_len)) 666 goto err; 667 if (!EVP_DigestUpdate(&mctx, ggen, sizeof(ggen))) 668 goto err; 669 if (!EVP_DigestUpdate(&mctx, md, 3)) 670 goto err; 671 if (!EVP_DigestFinal_ex(&mctx, md, NULL)) 672 goto err; 673 if (!BN_bin2bn(md, mdsize, test)) 674 goto err; 675 } 676 /* g=test^r0%p */ 677 if (!BN_mod_exp_mont(g, test, r0, p, ctx, mont)) 678 goto err; 679 if (!BN_is_one(g)) 680 break; 681 if (idx < 0 && !BN_add(test, test, BN_value_one())) 682 goto err; 683 h++; 684 if (idx >= 0 && h > 0xffff) 685 goto err; 686 } 687 688 if (!BN_GENCB_call(cb, 3, 1)) 689 goto err; 690 691 ok = 1; 692 err: 693 if (ok == 1) { 694 if (p != ret->p) { 695 if (ret->p) 696 BN_free(ret->p); 697 ret->p = BN_dup(p); 698 } 699 if (q != ret->q) { 700 if (ret->q) 701 BN_free(ret->q); 702 ret->q = BN_dup(q); 703 } 704 if (ret->g) 705 BN_free(ret->g); 706 ret->g = BN_dup(g); 707 if (ret->p == NULL || ret->q == NULL || ret->g == NULL) { 708 ok = -1; 709 goto err; 710 } 711 if (counter_ret != NULL) 712 *counter_ret = counter; 713 if (h_ret != NULL) 714 *h_ret = h; 715 } 716 if (seed) 717 OPENSSL_free(seed); 718 if (seed_out != seed_tmp) 719 OPENSSL_free(seed_tmp); 720 if (ctx) { 721 BN_CTX_end(ctx); 722 BN_CTX_free(ctx); 723 } 724 if (mont != NULL) 725 BN_MONT_CTX_free(mont); 726 EVP_MD_CTX_cleanup(&mctx); 727 return ok; 728} 729 730int dsa_paramgen_check_g(DSA *dsa) 731{ 732 BN_CTX *ctx; 733 BIGNUM *tmp; 734 BN_MONT_CTX *mont = NULL; 735 int rv = -1; 736 ctx = BN_CTX_new(); 737 if (!ctx) 738 return -1; 739 BN_CTX_start(ctx); 740 if (BN_cmp(dsa->g, BN_value_one()) <= 0) 741 return 0; 742 if (BN_cmp(dsa->g, dsa->p) >= 0) 743 return 0; 744 tmp = BN_CTX_get(ctx); 745 if (!tmp) 746 goto err; 747 if ((mont = BN_MONT_CTX_new()) == NULL) 748 goto err; 749 if (!BN_MONT_CTX_set(mont, dsa->p, ctx)) 750 goto err; 751 /* Work out g^q mod p */ 752 if (!BN_mod_exp_mont(tmp, dsa->g, dsa->q, dsa->p, ctx, mont)) 753 goto err; 754 if (!BN_cmp(tmp, BN_value_one())) 755 rv = 1; 756 else 757 rv = 0; 758 err: 759 BN_CTX_end(ctx); 760 if (mont) 761 BN_MONT_CTX_free(mont); 762 BN_CTX_free(ctx); 763 return rv; 764 765} 766#endif 767