1 /* $OpenBSD: moduli.c,v 1.30 2015/01/20 23:14:00 deraadt Exp $ */ 2 /* 3 * Copyright 1994 Phil Karn <karn (at) qualcomm.com> 4 * Copyright 1996-1998, 2003 William Allen Simpson <wsimpson (at) greendragon.com> 5 * Copyright 2000 Niels Provos <provos (at) citi.umich.edu> 6 * 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 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 18 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 19 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 20 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 21 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 22 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 23 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 24 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 26 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 27 */ 28 29 /* 30 * Two-step process to generate safe primes for DHGEX 31 * 32 * Sieve candidates for "safe" primes, 33 * suitable for use as Diffie-Hellman moduli; 34 * that is, where q = (p-1)/2 is also prime. 35 * 36 * First step: generate candidate primes (memory intensive) 37 * Second step: test primes' safety (processor intensive) 38 */ 39 40 #include "includes.h" 41 42 #ifdef WITH_OPENSSL 43 44 #include <sys/param.h> /* MAX */ 45 #include <sys/types.h> 46 47 #include <openssl/bn.h> 48 #include <openssl/dh.h> 49 50 #include <errno.h> 51 #include <stdio.h> 52 #include <stdlib.h> 53 #include <string.h> 54 #include <stdarg.h> 55 #include <time.h> 56 #include <unistd.h> 57 #include <limits.h> 58 59 #include "xmalloc.h" 60 #include "dh.h" 61 #include "log.h" 62 #include "misc.h" 63 64 #include "openbsd-compat/openssl-compat.h" 65 66 /* 67 * File output defines 68 */ 69 70 /* need line long enough for largest moduli plus headers */ 71 #define QLINESIZE (100+8192) 72 73 /* 74 * Size: decimal. 75 * Specifies the number of the most significant bit (0 to M). 76 * WARNING: internally, usually 1 to N. 77 */ 78 #define QSIZE_MINIMUM (511) 79 80 /* 81 * Prime sieving defines 82 */ 83 84 /* Constant: assuming 8 bit bytes and 32 bit words */ 85 #define SHIFT_BIT (3) 86 #define SHIFT_BYTE (2) 87 #define SHIFT_WORD (SHIFT_BIT+SHIFT_BYTE) 88 #define SHIFT_MEGABYTE (20) 89 #define SHIFT_MEGAWORD (SHIFT_MEGABYTE-SHIFT_BYTE) 90 91 /* 92 * Using virtual memory can cause thrashing. This should be the largest 93 * number that is supported without a large amount of disk activity -- 94 * that would increase the run time from hours to days or weeks! 95 */ 96 #define LARGE_MINIMUM (8UL) /* megabytes */ 97 98 /* 99 * Do not increase this number beyond the unsigned integer bit size. 100 * Due to a multiple of 4, it must be LESS than 128 (yielding 2**30 bits). 101 */ 102 #define LARGE_MAXIMUM (127UL) /* megabytes */ 103 104 /* 105 * Constant: when used with 32-bit integers, the largest sieve prime 106 * has to be less than 2**32. 107 */ 108 #define SMALL_MAXIMUM (0xffffffffUL) 109 110 /* Constant: can sieve all primes less than 2**32, as 65537**2 > 2**32-1. */ 111 #define TINY_NUMBER (1UL<<16) 112 113 /* Ensure enough bit space for testing 2*q. */ 114 #define TEST_MAXIMUM (1UL<<16) 115 #define TEST_MINIMUM (QSIZE_MINIMUM + 1) 116 /* real TEST_MINIMUM (1UL << (SHIFT_WORD - TEST_POWER)) */ 117 #define TEST_POWER (3) /* 2**n, n < SHIFT_WORD */ 118 119 /* bit operations on 32-bit words */ 120 #define BIT_CLEAR(a,n) ((a)[(n)>>SHIFT_WORD] &= ~(1L << ((n) & 31))) 121 #define BIT_SET(a,n) ((a)[(n)>>SHIFT_WORD] |= (1L << ((n) & 31))) 122 #define BIT_TEST(a,n) ((a)[(n)>>SHIFT_WORD] & (1L << ((n) & 31))) 123 124 /* 125 * Prime testing defines 126 */ 127 128 /* Minimum number of primality tests to perform */ 129 #define TRIAL_MINIMUM (4) 130 131 /* 132 * Sieving data (XXX - move to struct) 133 */ 134 135 /* sieve 2**16 */ 136 static u_int32_t *TinySieve, tinybits; 137 138 /* sieve 2**30 in 2**16 parts */ 139 static u_int32_t *SmallSieve, smallbits, smallbase; 140 141 /* sieve relative to the initial value */ 142 static u_int32_t *LargeSieve, largewords, largetries, largenumbers; 143 static u_int32_t largebits, largememory; /* megabytes */ 144 static BIGNUM *largebase; 145 146 int gen_candidates(FILE *, u_int32_t, u_int32_t, BIGNUM *); 147 int prime_test(FILE *, FILE *, u_int32_t, u_int32_t, char *, unsigned long, 148 unsigned long); 149 150 /* 151 * print moduli out in consistent form, 152 */ 153 static int 154 qfileout(FILE * ofile, u_int32_t otype, u_int32_t otests, u_int32_t otries, 155 u_int32_t osize, u_int32_t ogenerator, BIGNUM * omodulus) 156 { 157 struct tm *gtm; 158 time_t time_now; 159 int res; 160 161 time(&time_now); 162 gtm = gmtime(&time_now); 163 164 res = fprintf(ofile, "%04d%02d%02d%02d%02d%02d %u %u %u %u %x ", 165 gtm->tm_year + 1900, gtm->tm_mon + 1, gtm->tm_mday, 166 gtm->tm_hour, gtm->tm_min, gtm->tm_sec, 167 otype, otests, otries, osize, ogenerator); 168 169 if (res < 0) 170 return (-1); 171 172 if (BN_print_fp(ofile, omodulus) < 1) 173 return (-1); 174 175 res = fprintf(ofile, "\n"); 176 fflush(ofile); 177 178 return (res > 0 ? 0 : -1); 179 } 180 181 182 /* 183 ** Sieve p's and q's with small factors 184 */ 185 static void 186 sieve_large(u_int32_t s) 187 { 188 u_int32_t r, u; 189 190 debug3("sieve_large %u", s); 191 largetries++; 192 /* r = largebase mod s */ 193 r = BN_mod_word(largebase, s); 194 if (r == 0) 195 u = 0; /* s divides into largebase exactly */ 196 else 197 u = s - r; /* largebase+u is first entry divisible by s */ 198 199 if (u < largebits * 2) { 200 /* 201 * The sieve omits p's and q's divisible by 2, so ensure that 202 * largebase+u is odd. Then, step through the sieve in 203 * increments of 2*s 204 */ 205 if (u & 0x1) 206 u += s; /* Make largebase+u odd, and u even */ 207 208 /* Mark all multiples of 2*s */ 209 for (u /= 2; u < largebits; u += s) 210 BIT_SET(LargeSieve, u); 211 } 212 213 /* r = p mod s */ 214 r = (2 * r + 1) % s; 215 if (r == 0) 216 u = 0; /* s divides p exactly */ 217 else 218 u = s - r; /* p+u is first entry divisible by s */ 219 220 if (u < largebits * 4) { 221 /* 222 * The sieve omits p's divisible by 4, so ensure that 223 * largebase+u is not. Then, step through the sieve in 224 * increments of 4*s 225 */ 226 while (u & 0x3) { 227 if (SMALL_MAXIMUM - u < s) 228 return; 229 u += s; 230 } 231 232 /* Mark all multiples of 4*s */ 233 for (u /= 4; u < largebits; u += s) 234 BIT_SET(LargeSieve, u); 235 } 236 } 237 238 /* 239 * list candidates for Sophie-Germain primes (where q = (p-1)/2) 240 * to standard output. 241 * The list is checked against small known primes (less than 2**30). 242 */ 243 int 244 gen_candidates(FILE *out, u_int32_t memory, u_int32_t power, BIGNUM *start) 245 { 246 BIGNUM *q; 247 u_int32_t j, r, s, t; 248 u_int32_t smallwords = TINY_NUMBER >> 6; 249 u_int32_t tinywords = TINY_NUMBER >> 6; 250 time_t time_start, time_stop; 251 u_int32_t i; 252 int ret = 0; 253 254 largememory = memory; 255 256 if (memory != 0 && 257 (memory < LARGE_MINIMUM || memory > LARGE_MAXIMUM)) { 258 error("Invalid memory amount (min %ld, max %ld)", 259 LARGE_MINIMUM, LARGE_MAXIMUM); 260 return (-1); 261 } 262 263 /* 264 * Set power to the length in bits of the prime to be generated. 265 * This is changed to 1 less than the desired safe prime moduli p. 266 */ 267 if (power > TEST_MAXIMUM) { 268 error("Too many bits: %u > %lu", power, TEST_MAXIMUM); 269 return (-1); 270 } else if (power < TEST_MINIMUM) { 271 error("Too few bits: %u < %u", power, TEST_MINIMUM); 272 return (-1); 273 } 274 power--; /* decrement before squaring */ 275 276 /* 277 * The density of ordinary primes is on the order of 1/bits, so the 278 * density of safe primes should be about (1/bits)**2. Set test range 279 * to something well above bits**2 to be reasonably sure (but not 280 * guaranteed) of catching at least one safe prime. 281 */ 282 largewords = ((power * power) >> (SHIFT_WORD - TEST_POWER)); 283 284 /* 285 * Need idea of how much memory is available. We don't have to use all 286 * of it. 287 */ 288 if (largememory > LARGE_MAXIMUM) { 289 logit("Limited memory: %u MB; limit %lu MB", 290 largememory, LARGE_MAXIMUM); 291 largememory = LARGE_MAXIMUM; 292 } 293 294 if (largewords <= (largememory << SHIFT_MEGAWORD)) { 295 logit("Increased memory: %u MB; need %u bytes", 296 largememory, (largewords << SHIFT_BYTE)); 297 largewords = (largememory << SHIFT_MEGAWORD); 298 } else if (largememory > 0) { 299 logit("Decreased memory: %u MB; want %u bytes", 300 largememory, (largewords << SHIFT_BYTE)); 301 largewords = (largememory << SHIFT_MEGAWORD); 302 } 303 304 TinySieve = xcalloc(tinywords, sizeof(u_int32_t)); 305 tinybits = tinywords << SHIFT_WORD; 306 307 SmallSieve = xcalloc(smallwords, sizeof(u_int32_t)); 308 smallbits = smallwords << SHIFT_WORD; 309 310 /* 311 * dynamically determine available memory 312 */ 313 while ((LargeSieve = calloc(largewords, sizeof(u_int32_t))) == NULL) 314 largewords -= (1L << (SHIFT_MEGAWORD - 2)); /* 1/4 MB chunks */ 315 316 largebits = largewords << SHIFT_WORD; 317 largenumbers = largebits * 2; /* even numbers excluded */ 318 319 /* validation check: count the number of primes tried */ 320 largetries = 0; 321 if ((q = BN_new()) == NULL) 322 fatal("BN_new failed"); 323 324 /* 325 * Generate random starting point for subprime search, or use 326 * specified parameter. 327 */ 328 if ((largebase = BN_new()) == NULL) 329 fatal("BN_new failed"); 330 if (start == NULL) { 331 if (BN_rand(largebase, power, 1, 1) == 0) 332 fatal("BN_rand failed"); 333 } else { 334 if (BN_copy(largebase, start) == NULL) 335 fatal("BN_copy: failed"); 336 } 337 338 /* ensure odd */ 339 if (BN_set_bit(largebase, 0) == 0) 340 fatal("BN_set_bit: failed"); 341 342 time(&time_start); 343 344 logit("%.24s Sieve next %u plus %u-bit", ctime(&time_start), 345 largenumbers, power); 346 debug2("start point: 0x%s", BN_bn2hex(largebase)); 347 348 /* 349 * TinySieve 350 */ 351 for (i = 0; i < tinybits; i++) { 352 if (BIT_TEST(TinySieve, i)) 353 continue; /* 2*i+3 is composite */ 354 355 /* The next tiny prime */ 356 t = 2 * i + 3; 357 358 /* Mark all multiples of t */ 359 for (j = i + t; j < tinybits; j += t) 360 BIT_SET(TinySieve, j); 361 362 sieve_large(t); 363 } 364 365 /* 366 * Start the small block search at the next possible prime. To avoid 367 * fencepost errors, the last pass is skipped. 368 */ 369 for (smallbase = TINY_NUMBER + 3; 370 smallbase < (SMALL_MAXIMUM - TINY_NUMBER); 371 smallbase += TINY_NUMBER) { 372 for (i = 0; i < tinybits; i++) { 373 if (BIT_TEST(TinySieve, i)) 374 continue; /* 2*i+3 is composite */ 375 376 /* The next tiny prime */ 377 t = 2 * i + 3; 378 r = smallbase % t; 379 380 if (r == 0) { 381 s = 0; /* t divides into smallbase exactly */ 382 } else { 383 /* smallbase+s is first entry divisible by t */ 384 s = t - r; 385 } 386 387 /* 388 * The sieve omits even numbers, so ensure that 389 * smallbase+s is odd. Then, step through the sieve 390 * in increments of 2*t 391 */ 392 if (s & 1) 393 s += t; /* Make smallbase+s odd, and s even */ 394 395 /* Mark all multiples of 2*t */ 396 for (s /= 2; s < smallbits; s += t) 397 BIT_SET(SmallSieve, s); 398 } 399 400 /* 401 * SmallSieve 402 */ 403 for (i = 0; i < smallbits; i++) { 404 if (BIT_TEST(SmallSieve, i)) 405 continue; /* 2*i+smallbase is composite */ 406 407 /* The next small prime */ 408 sieve_large((2 * i) + smallbase); 409 } 410 411 memset(SmallSieve, 0, smallwords << SHIFT_BYTE); 412 } 413 414 time(&time_stop); 415 416 logit("%.24s Sieved with %u small primes in %ld seconds", 417 ctime(&time_stop), largetries, (long) (time_stop - time_start)); 418 419 for (j = r = 0; j < largebits; j++) { 420 if (BIT_TEST(LargeSieve, j)) 421 continue; /* Definitely composite, skip */ 422 423 debug2("test q = largebase+%u", 2 * j); 424 if (BN_set_word(q, 2 * j) == 0) 425 fatal("BN_set_word failed"); 426 if (BN_add(q, q, largebase) == 0) 427 fatal("BN_add failed"); 428 if (qfileout(out, MODULI_TYPE_SOPHIE_GERMAIN, 429 MODULI_TESTS_SIEVE, largetries, 430 (power - 1) /* MSB */, (0), q) == -1) { 431 ret = -1; 432 break; 433 } 434 435 r++; /* count q */ 436 } 437 438 time(&time_stop); 439 440 free(LargeSieve); 441 free(SmallSieve); 442 free(TinySieve); 443 444 logit("%.24s Found %u candidates", ctime(&time_stop), r); 445 446 return (ret); 447 } 448 449 static void 450 write_checkpoint(char *cpfile, u_int32_t lineno) 451 { 452 FILE *fp; 453 char tmp[PATH_MAX]; 454 int r; 455 456 r = snprintf(tmp, sizeof(tmp), "%s.XXXXXXXXXX", cpfile); 457 if (r == -1 || r >= PATH_MAX) { 458 logit("write_checkpoint: temp pathname too long"); 459 return; 460 } 461 if ((r = mkstemp(tmp)) == -1) { 462 logit("mkstemp(%s): %s", tmp, strerror(errno)); 463 return; 464 } 465 if ((fp = fdopen(r, "w")) == NULL) { 466 logit("write_checkpoint: fdopen: %s", strerror(errno)); 467 unlink(tmp); 468 close(r); 469 return; 470 } 471 if (fprintf(fp, "%lu\n", (unsigned long)lineno) > 0 && fclose(fp) == 0 472 && rename(tmp, cpfile) == 0) 473 debug3("wrote checkpoint line %lu to '%s'", 474 (unsigned long)lineno, cpfile); 475 else 476 logit("failed to write to checkpoint file '%s': %s", cpfile, 477 strerror(errno)); 478 } 479 480 static unsigned long 481 read_checkpoint(char *cpfile) 482 { 483 FILE *fp; 484 unsigned long lineno = 0; 485 486 if ((fp = fopen(cpfile, "r")) == NULL) 487 return 0; 488 if (fscanf(fp, "%lu\n", &lineno) < 1) 489 logit("Failed to load checkpoint from '%s'", cpfile); 490 else 491 logit("Loaded checkpoint from '%s' line %lu", cpfile, lineno); 492 fclose(fp); 493 return lineno; 494 } 495 496 static unsigned long 497 count_lines(FILE *f) 498 { 499 unsigned long count = 0; 500 char lp[QLINESIZE + 1]; 501 502 if (fseek(f, 0, SEEK_SET) != 0) { 503 debug("input file is not seekable"); 504 return ULONG_MAX; 505 } 506 while (fgets(lp, QLINESIZE + 1, f) != NULL) 507 count++; 508 rewind(f); 509 debug("input file has %lu lines", count); 510 return count; 511 } 512 513 static char * 514 fmt_time(time_t seconds) 515 { 516 int day, hr, min; 517 static char buf[128]; 518 519 min = (seconds / 60) % 60; 520 hr = (seconds / 60 / 60) % 24; 521 day = seconds / 60 / 60 / 24; 522 if (day > 0) 523 snprintf(buf, sizeof buf, "%dd %d:%02d", day, hr, min); 524 else 525 snprintf(buf, sizeof buf, "%d:%02d", hr, min); 526 return buf; 527 } 528 529 static void 530 print_progress(unsigned long start_lineno, unsigned long current_lineno, 531 unsigned long end_lineno) 532 { 533 static time_t time_start, time_prev; 534 time_t time_now, elapsed; 535 unsigned long num_to_process, processed, remaining, percent, eta; 536 double time_per_line; 537 char *eta_str; 538 539 time_now = monotime(); 540 if (time_start == 0) { 541 time_start = time_prev = time_now; 542 return; 543 } 544 /* print progress after 1m then once per 5m */ 545 if (time_now - time_prev < 5 * 60) 546 return; 547 time_prev = time_now; 548 elapsed = time_now - time_start; 549 processed = current_lineno - start_lineno; 550 remaining = end_lineno - current_lineno; 551 num_to_process = end_lineno - start_lineno; 552 time_per_line = (double)elapsed / processed; 553 /* if we don't know how many we're processing just report count+time */ 554 time(&time_now); 555 if (end_lineno == ULONG_MAX) { 556 logit("%.24s processed %lu in %s", ctime(&time_now), 557 processed, fmt_time(elapsed)); 558 return; 559 } 560 percent = 100 * processed / num_to_process; 561 eta = time_per_line * remaining; 562 eta_str = xstrdup(fmt_time(eta)); 563 logit("%.24s processed %lu of %lu (%lu%%) in %s, ETA %s", 564 ctime(&time_now), processed, num_to_process, percent, 565 fmt_time(elapsed), eta_str); 566 free(eta_str); 567 } 568 569 /* 570 * perform a Miller-Rabin primality test 571 * on the list of candidates 572 * (checking both q and p) 573 * The result is a list of so-call "safe" primes 574 */ 575 int 576 prime_test(FILE *in, FILE *out, u_int32_t trials, u_int32_t generator_wanted, 577 char *checkpoint_file, unsigned long start_lineno, unsigned long num_lines) 578 { 579 BIGNUM *q, *p, *a; 580 BN_CTX *ctx; 581 char *cp, *lp; 582 u_int32_t count_in = 0, count_out = 0, count_possible = 0; 583 u_int32_t generator_known, in_tests, in_tries, in_type, in_size; 584 unsigned long last_processed = 0, end_lineno; 585 time_t time_start, time_stop; 586 int res; 587 588 if (trials < TRIAL_MINIMUM) { 589 error("Minimum primality trials is %d", TRIAL_MINIMUM); 590 return (-1); 591 } 592 593 if (num_lines == 0) 594 end_lineno = count_lines(in); 595 else 596 end_lineno = start_lineno + num_lines; 597 598 time(&time_start); 599 600 if ((p = BN_new()) == NULL) 601 fatal("BN_new failed"); 602 if ((q = BN_new()) == NULL) 603 fatal("BN_new failed"); 604 if ((ctx = BN_CTX_new()) == NULL) 605 fatal("BN_CTX_new failed"); 606 607 debug2("%.24s Final %u Miller-Rabin trials (%x generator)", 608 ctime(&time_start), trials, generator_wanted); 609 610 if (checkpoint_file != NULL) 611 last_processed = read_checkpoint(checkpoint_file); 612 last_processed = start_lineno = MAX(last_processed, start_lineno); 613 if (end_lineno == ULONG_MAX) 614 debug("process from line %lu from pipe", last_processed); 615 else 616 debug("process from line %lu to line %lu", last_processed, 617 end_lineno); 618 619 res = 0; 620 lp = xmalloc(QLINESIZE + 1); 621 while (fgets(lp, QLINESIZE + 1, in) != NULL && count_in < end_lineno) { 622 count_in++; 623 if (count_in <= last_processed) { 624 debug3("skipping line %u, before checkpoint or " 625 "specified start line", count_in); 626 continue; 627 } 628 if (checkpoint_file != NULL) 629 write_checkpoint(checkpoint_file, count_in); 630 print_progress(start_lineno, count_in, end_lineno); 631 if (strlen(lp) < 14 || *lp == '!' || *lp == '#') { 632 debug2("%10u: comment or short line", count_in); 633 continue; 634 } 635 636 /* XXX - fragile parser */ 637 /* time */ 638 cp = &lp[14]; /* (skip) */ 639 640 /* type */ 641 in_type = strtoul(cp, &cp, 10); 642 643 /* tests */ 644 in_tests = strtoul(cp, &cp, 10); 645 646 if (in_tests & MODULI_TESTS_COMPOSITE) { 647 debug2("%10u: known composite", count_in); 648 continue; 649 } 650 651 /* tries */ 652 in_tries = strtoul(cp, &cp, 10); 653 654 /* size (most significant bit) */ 655 in_size = strtoul(cp, &cp, 10); 656 657 /* generator (hex) */ 658 generator_known = strtoul(cp, &cp, 16); 659 660 /* Skip white space */ 661 cp += strspn(cp, " "); 662 663 /* modulus (hex) */ 664 switch (in_type) { 665 case MODULI_TYPE_SOPHIE_GERMAIN: 666 debug2("%10u: (%u) Sophie-Germain", count_in, in_type); 667 a = q; 668 if (BN_hex2bn(&a, cp) == 0) 669 fatal("BN_hex2bn failed"); 670 /* p = 2*q + 1 */ 671 if (BN_lshift(p, q, 1) == 0) 672 fatal("BN_lshift failed"); 673 if (BN_add_word(p, 1) == 0) 674 fatal("BN_add_word failed"); 675 in_size += 1; 676 generator_known = 0; 677 break; 678 case MODULI_TYPE_UNSTRUCTURED: 679 case MODULI_TYPE_SAFE: 680 case MODULI_TYPE_SCHNORR: 681 case MODULI_TYPE_STRONG: 682 case MODULI_TYPE_UNKNOWN: 683 debug2("%10u: (%u)", count_in, in_type); 684 a = p; 685 if (BN_hex2bn(&a, cp) == 0) 686 fatal("BN_hex2bn failed"); 687 /* q = (p-1) / 2 */ 688 if (BN_rshift(q, p, 1) == 0) 689 fatal("BN_rshift failed"); 690 break; 691 default: 692 debug2("Unknown prime type"); 693 break; 694 } 695 696 /* 697 * due to earlier inconsistencies in interpretation, check 698 * the proposed bit size. 699 */ 700 if ((u_int32_t)BN_num_bits(p) != (in_size + 1)) { 701 debug2("%10u: bit size %u mismatch", count_in, in_size); 702 continue; 703 } 704 if (in_size < QSIZE_MINIMUM) { 705 debug2("%10u: bit size %u too short", count_in, in_size); 706 continue; 707 } 708 709 if (in_tests & MODULI_TESTS_MILLER_RABIN) 710 in_tries += trials; 711 else 712 in_tries = trials; 713 714 /* 715 * guess unknown generator 716 */ 717 if (generator_known == 0) { 718 if (BN_mod_word(p, 24) == 11) 719 generator_known = 2; 720 else if (BN_mod_word(p, 12) == 5) 721 generator_known = 3; 722 else { 723 u_int32_t r = BN_mod_word(p, 10); 724 725 if (r == 3 || r == 7) 726 generator_known = 5; 727 } 728 } 729 /* 730 * skip tests when desired generator doesn't match 731 */ 732 if (generator_wanted > 0 && 733 generator_wanted != generator_known) { 734 debug2("%10u: generator %d != %d", 735 count_in, generator_known, generator_wanted); 736 continue; 737 } 738 739 /* 740 * Primes with no known generator are useless for DH, so 741 * skip those. 742 */ 743 if (generator_known == 0) { 744 debug2("%10u: no known generator", count_in); 745 continue; 746 } 747 748 count_possible++; 749 750 /* 751 * The (1/4)^N performance bound on Miller-Rabin is 752 * extremely pessimistic, so don't spend a lot of time 753 * really verifying that q is prime until after we know 754 * that p is also prime. A single pass will weed out the 755 * vast majority of composite q's. 756 */ 757 if (BN_is_prime_ex(q, 1, ctx, NULL) <= 0) { 758 debug("%10u: q failed first possible prime test", 759 count_in); 760 continue; 761 } 762 763 /* 764 * q is possibly prime, so go ahead and really make sure 765 * that p is prime. If it is, then we can go back and do 766 * the same for q. If p is composite, chances are that 767 * will show up on the first Rabin-Miller iteration so it 768 * doesn't hurt to specify a high iteration count. 769 */ 770 if (!BN_is_prime_ex(p, trials, ctx, NULL)) { 771 debug("%10u: p is not prime", count_in); 772 continue; 773 } 774 debug("%10u: p is almost certainly prime", count_in); 775 776 /* recheck q more rigorously */ 777 if (!BN_is_prime_ex(q, trials - 1, ctx, NULL)) { 778 debug("%10u: q is not prime", count_in); 779 continue; 780 } 781 debug("%10u: q is almost certainly prime", count_in); 782 783 if (qfileout(out, MODULI_TYPE_SAFE, 784 in_tests | MODULI_TESTS_MILLER_RABIN, 785 in_tries, in_size, generator_known, p)) { 786 res = -1; 787 break; 788 } 789 790 count_out++; 791 } 792 793 time(&time_stop); 794 free(lp); 795 BN_free(p); 796 BN_free(q); 797 BN_CTX_free(ctx); 798 799 if (checkpoint_file != NULL) 800 unlink(checkpoint_file); 801 802 logit("%.24s Found %u safe primes of %u candidates in %ld seconds", 803 ctime(&time_stop), count_out, count_possible, 804 (long) (time_stop - time_start)); 805 806 return (res); 807 } 808 809 #endif /* WITH_OPENSSL */ 810
