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