1 /* $OpenBSD: moduli.c,v 1.28 2013/10/24 00:49:49 dtucker Exp $ */ 2 /* 3 * Copyright 1994 Phil Karn <karn@qualcomm.com> 4 * Copyright 1996-1998, 2003 William Allen Simpson <wsimpson@greendragon.com> 5 * Copyright 2000 Niels Provos <provos@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 <sys/param.h> 41 #include <sys/types.h> 42 43 #include <openssl/bn.h> 44 #include <openssl/dh.h> 45 46 #include <errno.h> 47 #include <stdio.h> 48 #include <stdlib.h> 49 #include <string.h> 50 #include <stdarg.h> 51 #include <time.h> 52 #include <unistd.h> 53 54 #include "xmalloc.h" 55 #include "dh.h" 56 #include "log.h" 57 #include "misc.h" 58 59 /* 60 * File output defines 61 */ 62 63 /* need line long enough for largest moduli plus headers */ 64 #define QLINESIZE (100+8192) 65 66 /* 67 * Size: decimal. 68 * Specifies the number of the most significant bit (0 to M). 69 * WARNING: internally, usually 1 to N. 70 */ 71 #define QSIZE_MINIMUM (511) 72 73 /* 74 * Prime sieving defines 75 */ 76 77 /* Constant: assuming 8 bit bytes and 32 bit words */ 78 #define SHIFT_BIT (3) 79 #define SHIFT_BYTE (2) 80 #define SHIFT_WORD (SHIFT_BIT+SHIFT_BYTE) 81 #define SHIFT_MEGABYTE (20) 82 #define SHIFT_MEGAWORD (SHIFT_MEGABYTE-SHIFT_BYTE) 83 84 /* 85 * Using virtual memory can cause thrashing. This should be the largest 86 * number that is supported without a large amount of disk activity -- 87 * that would increase the run time from hours to days or weeks! 88 */ 89 #define LARGE_MINIMUM (8UL) /* megabytes */ 90 91 /* 92 * Do not increase this number beyond the unsigned integer bit size. 93 * Due to a multiple of 4, it must be LESS than 128 (yielding 2**30 bits). 94 */ 95 #define LARGE_MAXIMUM (127UL) /* megabytes */ 96 97 /* 98 * Constant: when used with 32-bit integers, the largest sieve prime 99 * has to be less than 2**32. 100 */ 101 #define SMALL_MAXIMUM (0xffffffffUL) 102 103 /* Constant: can sieve all primes less than 2**32, as 65537**2 > 2**32-1. */ 104 #define TINY_NUMBER (1UL<<16) 105 106 /* Ensure enough bit space for testing 2*q. */ 107 #define TEST_MAXIMUM (1UL<<16) 108 #define TEST_MINIMUM (QSIZE_MINIMUM + 1) 109 /* real TEST_MINIMUM (1UL << (SHIFT_WORD - TEST_POWER)) */ 110 #define TEST_POWER (3) /* 2**n, n < SHIFT_WORD */ 111 112 /* bit operations on 32-bit words */ 113 #define BIT_CLEAR(a,n) ((a)[(n)>>SHIFT_WORD] &= ~(1L << ((n) & 31))) 114 #define BIT_SET(a,n) ((a)[(n)>>SHIFT_WORD] |= (1L << ((n) & 31))) 115 #define BIT_TEST(a,n) ((a)[(n)>>SHIFT_WORD] & (1L << ((n) & 31))) 116 117 /* 118 * Prime testing defines 119 */ 120 121 /* Minimum number of primality tests to perform */ 122 #define TRIAL_MINIMUM (4) 123 124 /* 125 * Sieving data (XXX - move to struct) 126 */ 127 128 /* sieve 2**16 */ 129 static u_int32_t *TinySieve, tinybits; 130 131 /* sieve 2**30 in 2**16 parts */ 132 static u_int32_t *SmallSieve, smallbits, smallbase; 133 134 /* sieve relative to the initial value */ 135 static u_int32_t *LargeSieve, largewords, largetries, largenumbers; 136 static u_int32_t largebits, largememory; /* megabytes */ 137 static BIGNUM *largebase; 138 139 int gen_candidates(FILE *, u_int32_t, u_int32_t, BIGNUM *); 140 int prime_test(FILE *, FILE *, u_int32_t, u_int32_t, char *, unsigned long, 141 unsigned long); 142 143 /* 144 * print moduli out in consistent form, 145 */ 146 static int 147 qfileout(FILE * ofile, u_int32_t otype, u_int32_t otests, u_int32_t otries, 148 u_int32_t osize, u_int32_t ogenerator, BIGNUM * omodulus) 149 { 150 struct tm *gtm; 151 time_t time_now; 152 int res; 153 154 time(&time_now); 155 gtm = gmtime(&time_now); 156 157 res = fprintf(ofile, "%04d%02d%02d%02d%02d%02d %u %u %u %u %x ", 158 gtm->tm_year + 1900, gtm->tm_mon + 1, gtm->tm_mday, 159 gtm->tm_hour, gtm->tm_min, gtm->tm_sec, 160 otype, otests, otries, osize, ogenerator); 161 162 if (res < 0) 163 return (-1); 164 165 if (BN_print_fp(ofile, omodulus) < 1) 166 return (-1); 167 168 res = fprintf(ofile, "\n"); 169 fflush(ofile); 170 171 return (res > 0 ? 0 : -1); 172 } 173 174 175 /* 176 ** Sieve p's and q's with small factors 177 */ 178 static void 179 sieve_large(u_int32_t s) 180 { 181 u_int32_t r, u; 182 183 debug3("sieve_large %u", s); 184 largetries++; 185 /* r = largebase mod s */ 186 r = BN_mod_word(largebase, s); 187 if (r == 0) 188 u = 0; /* s divides into largebase exactly */ 189 else 190 u = s - r; /* largebase+u is first entry divisible by s */ 191 192 if (u < largebits * 2) { 193 /* 194 * The sieve omits p's and q's divisible by 2, so ensure that 195 * largebase+u is odd. Then, step through the sieve in 196 * increments of 2*s 197 */ 198 if (u & 0x1) 199 u += s; /* Make largebase+u odd, and u even */ 200 201 /* Mark all multiples of 2*s */ 202 for (u /= 2; u < largebits; u += s) 203 BIT_SET(LargeSieve, u); 204 } 205 206 /* r = p mod s */ 207 r = (2 * r + 1) % s; 208 if (r == 0) 209 u = 0; /* s divides p exactly */ 210 else 211 u = s - r; /* p+u is first entry divisible by s */ 212 213 if (u < largebits * 4) { 214 /* 215 * The sieve omits p's divisible by 4, so ensure that 216 * largebase+u is not. Then, step through the sieve in 217 * increments of 4*s 218 */ 219 while (u & 0x3) { 220 if (SMALL_MAXIMUM - u < s) 221 return; 222 u += s; 223 } 224 225 /* Mark all multiples of 4*s */ 226 for (u /= 4; u < largebits; u += s) 227 BIT_SET(LargeSieve, u); 228 } 229 } 230 231 /* 232 * list candidates for Sophie-Germain primes (where q = (p-1)/2) 233 * to standard output. 234 * The list is checked against small known primes (less than 2**30). 235 */ 236 int 237 gen_candidates(FILE *out, u_int32_t memory, u_int32_t power, BIGNUM *start) 238 { 239 BIGNUM *q; 240 u_int32_t j, r, s, t; 241 u_int32_t smallwords = TINY_NUMBER >> 6; 242 u_int32_t tinywords = TINY_NUMBER >> 6; 243 time_t time_start, time_stop; 244 u_int32_t i; 245 int ret = 0; 246 247 largememory = memory; 248 249 if (memory != 0 && 250 (memory < LARGE_MINIMUM || memory > LARGE_MAXIMUM)) { 251 error("Invalid memory amount (min %ld, max %ld)", 252 LARGE_MINIMUM, LARGE_MAXIMUM); 253 return (-1); 254 } 255 256 /* 257 * Set power to the length in bits of the prime to be generated. 258 * This is changed to 1 less than the desired safe prime moduli p. 259 */ 260 if (power > TEST_MAXIMUM) { 261 error("Too many bits: %u > %lu", power, TEST_MAXIMUM); 262 return (-1); 263 } else if (power < TEST_MINIMUM) { 264 error("Too few bits: %u < %u", power, TEST_MINIMUM); 265 return (-1); 266 } 267 power--; /* decrement before squaring */ 268 269 /* 270 * The density of ordinary primes is on the order of 1/bits, so the 271 * density of safe primes should be about (1/bits)**2. Set test range 272 * to something well above bits**2 to be reasonably sure (but not 273 * guaranteed) of catching at least one safe prime. 274 */ 275 largewords = ((power * power) >> (SHIFT_WORD - TEST_POWER)); 276 277 /* 278 * Need idea of how much memory is available. We don't have to use all 279 * of it. 280 */ 281 if (largememory > LARGE_MAXIMUM) { 282 logit("Limited memory: %u MB; limit %lu MB", 283 largememory, LARGE_MAXIMUM); 284 largememory = LARGE_MAXIMUM; 285 } 286 287 if (largewords <= (largememory << SHIFT_MEGAWORD)) { 288 logit("Increased memory: %u MB; need %u bytes", 289 largememory, (largewords << SHIFT_BYTE)); 290 largewords = (largememory << SHIFT_MEGAWORD); 291 } else if (largememory > 0) { 292 logit("Decreased memory: %u MB; want %u bytes", 293 largememory, (largewords << SHIFT_BYTE)); 294 largewords = (largememory << SHIFT_MEGAWORD); 295 } 296 297 TinySieve = xcalloc(tinywords, sizeof(u_int32_t)); 298 tinybits = tinywords << SHIFT_WORD; 299 300 SmallSieve = xcalloc(smallwords, sizeof(u_int32_t)); 301 smallbits = smallwords << SHIFT_WORD; 302 303 /* 304 * dynamically determine available memory 305 */ 306 while ((LargeSieve = calloc(largewords, sizeof(u_int32_t))) == NULL) 307 largewords -= (1L << (SHIFT_MEGAWORD - 2)); /* 1/4 MB chunks */ 308 309 largebits = largewords << SHIFT_WORD; 310 largenumbers = largebits * 2; /* even numbers excluded */ 311 312 /* validation check: count the number of primes tried */ 313 largetries = 0; 314 if ((q = BN_new()) == NULL) 315 fatal("BN_new failed"); 316 317 /* 318 * Generate random starting point for subprime search, or use 319 * specified parameter. 320 */ 321 if ((largebase = BN_new()) == NULL) 322 fatal("BN_new failed"); 323 if (start == NULL) { 324 if (BN_rand(largebase, power, 1, 1) == 0) 325 fatal("BN_rand failed"); 326 } else { 327 if (BN_copy(largebase, start) == NULL) 328 fatal("BN_copy: failed"); 329 } 330 331 /* ensure odd */ 332 if (BN_set_bit(largebase, 0) == 0) 333 fatal("BN_set_bit: failed"); 334 335 time(&time_start); 336 337 logit("%.24s Sieve next %u plus %u-bit", ctime(&time_start), 338 largenumbers, power); 339 debug2("start point: 0x%s", BN_bn2hex(largebase)); 340 341 /* 342 * TinySieve 343 */ 344 for (i = 0; i < tinybits; i++) { 345 if (BIT_TEST(TinySieve, i)) 346 continue; /* 2*i+3 is composite */ 347 348 /* The next tiny prime */ 349 t = 2 * i + 3; 350 351 /* Mark all multiples of t */ 352 for (j = i + t; j < tinybits; j += t) 353 BIT_SET(TinySieve, j); 354 355 sieve_large(t); 356 } 357 358 /* 359 * Start the small block search at the next possible prime. To avoid 360 * fencepost errors, the last pass is skipped. 361 */ 362 for (smallbase = TINY_NUMBER + 3; 363 smallbase < (SMALL_MAXIMUM - TINY_NUMBER); 364 smallbase += TINY_NUMBER) { 365 for (i = 0; i < tinybits; i++) { 366 if (BIT_TEST(TinySieve, i)) 367 continue; /* 2*i+3 is composite */ 368 369 /* The next tiny prime */ 370 t = 2 * i + 3; 371 r = smallbase % t; 372 373 if (r == 0) { 374 s = 0; /* t divides into smallbase exactly */ 375 } else { 376 /* smallbase+s is first entry divisible by t */ 377 s = t - r; 378 } 379 380 /* 381 * The sieve omits even numbers, so ensure that 382 * smallbase+s is odd. Then, step through the sieve 383 * in increments of 2*t 384 */ 385 if (s & 1) 386 s += t; /* Make smallbase+s odd, and s even */ 387 388 /* Mark all multiples of 2*t */ 389 for (s /= 2; s < smallbits; s += t) 390 BIT_SET(SmallSieve, s); 391 } 392 393 /* 394 * SmallSieve 395 */ 396 for (i = 0; i < smallbits; i++) { 397 if (BIT_TEST(SmallSieve, i)) 398 continue; /* 2*i+smallbase is composite */ 399 400 /* The next small prime */ 401 sieve_large((2 * i) + smallbase); 402 } 403 404 memset(SmallSieve, 0, smallwords << SHIFT_BYTE); 405 } 406 407 time(&time_stop); 408 409 logit("%.24s Sieved with %u small primes in %ld seconds", 410 ctime(&time_stop), largetries, (long) (time_stop - time_start)); 411 412 for (j = r = 0; j < largebits; j++) { 413 if (BIT_TEST(LargeSieve, j)) 414 continue; /* Definitely composite, skip */ 415 416 debug2("test q = largebase+%u", 2 * j); 417 if (BN_set_word(q, 2 * j) == 0) 418 fatal("BN_set_word failed"); 419 if (BN_add(q, q, largebase) == 0) 420 fatal("BN_add failed"); 421 if (qfileout(out, MODULI_TYPE_SOPHIE_GERMAIN, 422 MODULI_TESTS_SIEVE, largetries, 423 (power - 1) /* MSB */, (0), q) == -1) { 424 ret = -1; 425 break; 426 } 427 428 r++; /* count q */ 429 } 430 431 time(&time_stop); 432 433 free(LargeSieve); 434 free(SmallSieve); 435 free(TinySieve); 436 437 logit("%.24s Found %u candidates", ctime(&time_stop), r); 438 439 return (ret); 440 } 441 442 static void 443 write_checkpoint(char *cpfile, u_int32_t lineno) 444 { 445 FILE *fp; 446 char tmp[MAXPATHLEN]; 447 int r; 448 449 r = snprintf(tmp, sizeof(tmp), "%s.XXXXXXXXXX", cpfile); 450 if (r == -1 || r >= MAXPATHLEN) { 451 logit("write_checkpoint: temp pathname too long"); 452 return; 453 } 454 if ((r = mkstemp(tmp)) == -1) { 455 logit("mkstemp(%s): %s", tmp, strerror(errno)); 456 return; 457 } 458 if ((fp = fdopen(r, "w")) == NULL) { 459 logit("write_checkpoint: fdopen: %s", strerror(errno)); 460 close(r); 461 return; 462 } 463 if (fprintf(fp, "%lu\n", (unsigned long)lineno) > 0 && fclose(fp) == 0 464 && rename(tmp, cpfile) == 0) 465 debug3("wrote checkpoint line %lu to '%s'", 466 (unsigned long)lineno, cpfile); 467 else 468 logit("failed to write to checkpoint file '%s': %s", cpfile, 469 strerror(errno)); 470 } 471 472 static unsigned long 473 read_checkpoint(char *cpfile) 474 { 475 FILE *fp; 476 unsigned long lineno = 0; 477 478 if ((fp = fopen(cpfile, "r")) == NULL) 479 return 0; 480 if (fscanf(fp, "%lu\n", &lineno) < 1) 481 logit("Failed to load checkpoint from '%s'", cpfile); 482 else 483 logit("Loaded checkpoint from '%s' line %lu", cpfile, lineno); 484 fclose(fp); 485 return lineno; 486 } 487 488 static unsigned long 489 count_lines(FILE *f) 490 { 491 unsigned long count = 0; 492 char lp[QLINESIZE + 1]; 493 494 if (fseek(f, 0, SEEK_SET) != 0) { 495 debug("input file is not seekable"); 496 return ULONG_MAX; 497 } 498 while (fgets(lp, QLINESIZE + 1, f) != NULL) 499 count++; 500 rewind(f); 501 debug("input file has %lu lines", count); 502 return count; 503 } 504 505 static char * 506 fmt_time(time_t seconds) 507 { 508 int day, hr, min; 509 static char buf[128]; 510 511 min = (seconds / 60) % 60; 512 hr = (seconds / 60 / 60) % 24; 513 day = seconds / 60 / 60 / 24; 514 if (day > 0) 515 snprintf(buf, sizeof buf, "%dd %d:%02d", day, hr, min); 516 else 517 snprintf(buf, sizeof buf, "%d:%02d", hr, min); 518 return buf; 519 } 520 521 static void 522 print_progress(unsigned long start_lineno, unsigned long current_lineno, 523 unsigned long end_lineno) 524 { 525 static time_t time_start, time_prev; 526 time_t time_now, elapsed; 527 unsigned long num_to_process, processed, remaining, percent, eta; 528 double time_per_line; 529 char *eta_str; 530 531 time_now = monotime(); 532 if (time_start == 0) { 533 time_start = time_prev = time_now; 534 return; 535 } 536 /* print progress after 1m then once per 5m */ 537 if (time_now - time_prev < 5 * 60) 538 return; 539 time_prev = time_now; 540 elapsed = time_now - time_start; 541 processed = current_lineno - start_lineno; 542 remaining = end_lineno - current_lineno; 543 num_to_process = end_lineno - start_lineno; 544 time_per_line = (double)elapsed / processed; 545 /* if we don't know how many we're processing just report count+time */ 546 time(&time_now); 547 if (end_lineno == ULONG_MAX) { 548 logit("%.24s processed %lu in %s", ctime(&time_now), 549 processed, fmt_time(elapsed)); 550 return; 551 } 552 percent = 100 * processed / num_to_process; 553 eta = time_per_line * remaining; 554 eta_str = xstrdup(fmt_time(eta)); 555 logit("%.24s processed %lu of %lu (%lu%%) in %s, ETA %s", 556 ctime(&time_now), processed, num_to_process, percent, 557 fmt_time(elapsed), eta_str); 558 free(eta_str); 559 } 560 561 /* 562 * perform a Miller-Rabin primality test 563 * on the list of candidates 564 * (checking both q and p) 565 * The result is a list of so-call "safe" primes 566 */ 567 int 568 prime_test(FILE *in, FILE *out, u_int32_t trials, u_int32_t generator_wanted, 569 char *checkpoint_file, unsigned long start_lineno, unsigned long num_lines) 570 { 571 BIGNUM *q, *p, *a; 572 BN_CTX *ctx; 573 char *cp, *lp; 574 u_int32_t count_in = 0, count_out = 0, count_possible = 0; 575 u_int32_t generator_known, in_tests, in_tries, in_type, in_size; 576 unsigned long last_processed = 0, end_lineno; 577 time_t time_start, time_stop; 578 int res; 579 580 if (trials < TRIAL_MINIMUM) { 581 error("Minimum primality trials is %d", TRIAL_MINIMUM); 582 return (-1); 583 } 584 585 if (num_lines == 0) 586 end_lineno = count_lines(in); 587 else 588 end_lineno = start_lineno + num_lines; 589 590 time(&time_start); 591 592 if ((p = BN_new()) == NULL) 593 fatal("BN_new failed"); 594 if ((q = BN_new()) == NULL) 595 fatal("BN_new failed"); 596 if ((ctx = BN_CTX_new()) == NULL) 597 fatal("BN_CTX_new failed"); 598 599 debug2("%.24s Final %u Miller-Rabin trials (%x generator)", 600 ctime(&time_start), trials, generator_wanted); 601 602 if (checkpoint_file != NULL) 603 last_processed = read_checkpoint(checkpoint_file); 604 last_processed = start_lineno = MAX(last_processed, start_lineno); 605 if (end_lineno == ULONG_MAX) 606 debug("process from line %lu from pipe", last_processed); 607 else 608 debug("process from line %lu to line %lu", last_processed, 609 end_lineno); 610 611 res = 0; 612 lp = xmalloc(QLINESIZE + 1); 613 while (fgets(lp, QLINESIZE + 1, in) != NULL && count_in < end_lineno) { 614 count_in++; 615 if (count_in <= last_processed) { 616 debug3("skipping line %u, before checkpoint or " 617 "specified start line", count_in); 618 continue; 619 } 620 if (checkpoint_file != NULL) 621 write_checkpoint(checkpoint_file, count_in); 622 print_progress(start_lineno, count_in, end_lineno); 623 if (strlen(lp) < 14 || *lp == '!' || *lp == '#') { 624 debug2("%10u: comment or short line", count_in); 625 continue; 626 } 627 628 /* XXX - fragile parser */ 629 /* time */ 630 cp = &lp[14]; /* (skip) */ 631 632 /* type */ 633 in_type = strtoul(cp, &cp, 10); 634 635 /* tests */ 636 in_tests = strtoul(cp, &cp, 10); 637 638 if (in_tests & MODULI_TESTS_COMPOSITE) { 639 debug2("%10u: known composite", count_in); 640 continue; 641 } 642 643 /* tries */ 644 in_tries = strtoul(cp, &cp, 10); 645 646 /* size (most significant bit) */ 647 in_size = strtoul(cp, &cp, 10); 648 649 /* generator (hex) */ 650 generator_known = strtoul(cp, &cp, 16); 651 652 /* Skip white space */ 653 cp += strspn(cp, " "); 654 655 /* modulus (hex) */ 656 switch (in_type) { 657 case MODULI_TYPE_SOPHIE_GERMAIN: 658 debug2("%10u: (%u) Sophie-Germain", count_in, in_type); 659 a = q; 660 if (BN_hex2bn(&a, cp) == 0) 661 fatal("BN_hex2bn failed"); 662 /* p = 2*q + 1 */ 663 if (BN_lshift(p, q, 1) == 0) 664 fatal("BN_lshift failed"); 665 if (BN_add_word(p, 1) == 0) 666 fatal("BN_add_word failed"); 667 in_size += 1; 668 generator_known = 0; 669 break; 670 case MODULI_TYPE_UNSTRUCTURED: 671 case MODULI_TYPE_SAFE: 672 case MODULI_TYPE_SCHNORR: 673 case MODULI_TYPE_STRONG: 674 case MODULI_TYPE_UNKNOWN: 675 debug2("%10u: (%u)", count_in, in_type); 676 a = p; 677 if (BN_hex2bn(&a, cp) == 0) 678 fatal("BN_hex2bn failed"); 679 /* q = (p-1) / 2 */ 680 if (BN_rshift(q, p, 1) == 0) 681 fatal("BN_rshift failed"); 682 break; 683 default: 684 debug2("Unknown prime type"); 685 break; 686 } 687 688 /* 689 * due to earlier inconsistencies in interpretation, check 690 * the proposed bit size. 691 */ 692 if ((u_int32_t)BN_num_bits(p) != (in_size + 1)) { 693 debug2("%10u: bit size %u mismatch", count_in, in_size); 694 continue; 695 } 696 if (in_size < QSIZE_MINIMUM) { 697 debug2("%10u: bit size %u too short", count_in, in_size); 698 continue; 699 } 700 701 if (in_tests & MODULI_TESTS_MILLER_RABIN) 702 in_tries += trials; 703 else 704 in_tries = trials; 705 706 /* 707 * guess unknown generator 708 */ 709 if (generator_known == 0) { 710 if (BN_mod_word(p, 24) == 11) 711 generator_known = 2; 712 else if (BN_mod_word(p, 12) == 5) 713 generator_known = 3; 714 else { 715 u_int32_t r = BN_mod_word(p, 10); 716 717 if (r == 3 || r == 7) 718 generator_known = 5; 719 } 720 } 721 /* 722 * skip tests when desired generator doesn't match 723 */ 724 if (generator_wanted > 0 && 725 generator_wanted != generator_known) { 726 debug2("%10u: generator %d != %d", 727 count_in, generator_known, generator_wanted); 728 continue; 729 } 730 731 /* 732 * Primes with no known generator are useless for DH, so 733 * skip those. 734 */ 735 if (generator_known == 0) { 736 debug2("%10u: no known generator", count_in); 737 continue; 738 } 739 740 count_possible++; 741 742 /* 743 * The (1/4)^N performance bound on Miller-Rabin is 744 * extremely pessimistic, so don't spend a lot of time 745 * really verifying that q is prime until after we know 746 * that p is also prime. A single pass will weed out the 747 * vast majority of composite q's. 748 */ 749 if (BN_is_prime_ex(q, 1, ctx, NULL) <= 0) { 750 debug("%10u: q failed first possible prime test", 751 count_in); 752 continue; 753 } 754 755 /* 756 * q is possibly prime, so go ahead and really make sure 757 * that p is prime. If it is, then we can go back and do 758 * the same for q. If p is composite, chances are that 759 * will show up on the first Rabin-Miller iteration so it 760 * doesn't hurt to specify a high iteration count. 761 */ 762 if (!BN_is_prime_ex(p, trials, ctx, NULL)) { 763 debug("%10u: p is not prime", count_in); 764 continue; 765 } 766 debug("%10u: p is almost certainly prime", count_in); 767 768 /* recheck q more rigorously */ 769 if (!BN_is_prime_ex(q, trials - 1, ctx, NULL)) { 770 debug("%10u: q is not prime", count_in); 771 continue; 772 } 773 debug("%10u: q is almost certainly prime", count_in); 774 775 if (qfileout(out, MODULI_TYPE_SAFE, 776 in_tests | MODULI_TESTS_MILLER_RABIN, 777 in_tries, in_size, generator_known, p)) { 778 res = -1; 779 break; 780 } 781 782 count_out++; 783 } 784 785 time(&time_stop); 786 free(lp); 787 BN_free(p); 788 BN_free(q); 789 BN_CTX_free(ctx); 790 791 if (checkpoint_file != NULL) 792 unlink(checkpoint_file); 793 794 logit("%.24s Found %u safe primes of %u candidates in %ld seconds", 795 ctime(&time_stop), count_out, count_possible, 796 (long) (time_stop - time_start)); 797 798 return (res); 799 } 800