1 /* $NetBSD: moduli.c,v 1.17 2023/07/26 17:58:15 christos Exp $ */
2 /* $OpenBSD: moduli.c,v 1.39 2023/03/02 06:41:56 dtucker Exp $ */
3 /*
4 * Copyright 1994 Phil Karn <karn@qualcomm.com>
5 * Copyright 1996-1998, 2003 William Allen Simpson <wsimpson@greendragon.com>
6 * Copyright 2000 Niels Provos <provos@citi.umich.edu>
7 * All rights reserved.
8 *
9 * Redistribution and use in source and binary forms, with or without
10 * modification, are permitted provided that the following conditions
11 * are met:
12 * 1. Redistributions of source code must retain the above copyright
13 * notice, this list of conditions and the following disclaimer.
14 * 2. Redistributions in binary form must reproduce the above copyright
15 * notice, this list of conditions and the following disclaimer in the
16 * documentation and/or other materials provided with the distribution.
17 *
18 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
19 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
20 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
21 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
22 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
23 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
24 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
25 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
26 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
27 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
28 */
29
30 /*
31 * Two-step process to generate safe primes for DHGEX
32 *
33 * Sieve candidates for "safe" primes,
34 * suitable for use as Diffie-Hellman moduli;
35 * that is, where q = (p-1)/2 is also prime.
36 *
37 * First step: generate candidate primes (memory intensive)
38 * Second step: test primes' safety (processor intensive)
39 */
40 #include "includes.h"
41 __RCSID("$NetBSD: moduli.c,v 1.17 2023/07/26 17:58:15 christos Exp $");
42
43 #include <sys/types.h>
44
45 #include <openssl/bn.h>
46 #include <openssl/dh.h>
47
48 #include <errno.h>
49 #include <stdio.h>
50 #include <stdlib.h>
51 #include <string.h>
52 #include <stdarg.h>
53 #include <time.h>
54 #include <unistd.h>
55 #include <limits.h>
56
57 #include "xmalloc.h"
58 #include "dh.h"
59 #include "log.h"
60 #include "misc.h"
61
62 /*
63 * File output defines
64 */
65
66 /* need line long enough for largest moduli plus headers */
67 #define QLINESIZE (100+8192)
68
69 /*
70 * Size: decimal.
71 * Specifies the number of the most significant bit (0 to M).
72 * WARNING: internally, usually 1 to N.
73 */
74 #define QSIZE_MINIMUM (511)
75
76 /*
77 * Prime sieving defines
78 */
79
80 /* Constant: assuming 8 bit bytes and 32 bit words */
81 #define SHIFT_BIT (3)
82 #define SHIFT_BYTE (2)
83 #define SHIFT_WORD (SHIFT_BIT+SHIFT_BYTE)
84 #define SHIFT_MEGABYTE (20)
85 #define SHIFT_MEGAWORD (SHIFT_MEGABYTE-SHIFT_BYTE)
86
87 /*
88 * Using virtual memory can cause thrashing. This should be the largest
89 * number that is supported without a large amount of disk activity --
90 * that would increase the run time from hours to days or weeks!
91 */
92 #define LARGE_MINIMUM (8UL) /* megabytes */
93
94 /*
95 * Do not increase this number beyond the unsigned integer bit size.
96 * Due to a multiple of 4, it must be LESS than 128 (yielding 2**30 bits).
97 */
98 #define LARGE_MAXIMUM (127UL) /* megabytes */
99
100 /*
101 * Constant: when used with 32-bit integers, the largest sieve prime
102 * has to be less than 2**32.
103 */
104 #define SMALL_MAXIMUM (0xffffffffUL)
105
106 /* Constant: can sieve all primes less than 2**32, as 65537**2 > 2**32-1. */
107 #define TINY_NUMBER (1UL<<16)
108
109 /* Ensure enough bit space for testing 2*q. */
110 #define TEST_MAXIMUM (1UL<<16)
111 #define TEST_MINIMUM (QSIZE_MINIMUM + 1)
112 /* real TEST_MINIMUM (1UL << (SHIFT_WORD - TEST_POWER)) */
113 #define TEST_POWER (3) /* 2**n, n < SHIFT_WORD */
114
115 /* bit operations on 32-bit words */
116 #define BIT_CLEAR(a,n) ((a)[(n)>>SHIFT_WORD] &= ~(1L << ((n) & 31)))
117 #define BIT_SET(a,n) ((a)[(n)>>SHIFT_WORD] |= (1L << ((n) & 31)))
118 #define BIT_TEST(a,n) ((a)[(n)>>SHIFT_WORD] & (1L << ((n) & 31)))
119
120 /*
121 * Prime testing defines
122 */
123
124 /* Minimum number of primality tests to perform */
125 #define TRIAL_MINIMUM (4)
126
127 /*
128 * Sieving data (XXX - move to struct)
129 */
130
131 /* sieve 2**16 */
132 static u_int32_t *TinySieve, tinybits;
133
134 /* sieve 2**30 in 2**16 parts */
135 static u_int32_t *SmallSieve, smallbits, smallbase;
136
137 /* sieve relative to the initial value */
138 static u_int32_t *LargeSieve, largewords, largetries, largenumbers;
139 static u_int32_t largebits, largememory; /* megabytes */
140 static BIGNUM *largebase;
141
142 int gen_candidates(FILE *, u_int32_t, u_int32_t, BIGNUM *);
143 int prime_test(FILE *, FILE *, u_int32_t, u_int32_t, char *, unsigned long,
144 unsigned long);
145
146 /*
147 * print moduli out in consistent form,
148 */
149 static int
qfileout(FILE * ofile,u_int32_t otype,u_int32_t otests,u_int32_t otries,u_int32_t osize,u_int32_t ogenerator,BIGNUM * omodulus)150 qfileout(FILE * ofile, u_int32_t otype, u_int32_t otests, u_int32_t otries,
151 u_int32_t osize, u_int32_t ogenerator, BIGNUM * omodulus)
152 {
153 struct tm *gtm;
154 time_t time_now;
155 int res;
156
157 time(&time_now);
158 gtm = gmtime(&time_now);
159 if (gtm == NULL)
160 return -1;
161
162 res = fprintf(ofile, "%04d%02d%02d%02d%02d%02d %u %u %u %u %x ",
163 gtm->tm_year + 1900, gtm->tm_mon + 1, gtm->tm_mday,
164 gtm->tm_hour, gtm->tm_min, gtm->tm_sec,
165 otype, otests, otries, osize, ogenerator);
166
167 if (res < 0)
168 return (-1);
169
170 if (BN_print_fp(ofile, omodulus) < 1)
171 return (-1);
172
173 res = fprintf(ofile, "\n");
174 fflush(ofile);
175
176 return (res > 0 ? 0 : -1);
177 }
178
179
180 /*
181 ** Sieve p's and q's with small factors
182 */
183 static void
sieve_large(u_int32_t s32)184 sieve_large(u_int32_t s32)
185 {
186 u_int64_t r, u, s = s32;
187
188 debug3("sieve_large %u", s32);
189 largetries++;
190 /* r = largebase mod s */
191 r = BN_mod_word(largebase, s32);
192 if (r == 0)
193 u = 0; /* s divides into largebase exactly */
194 else
195 u = s - r; /* largebase+u is first entry divisible by s */
196
197 if (u < largebits * 2ULL) {
198 /*
199 * The sieve omits p's and q's divisible by 2, so ensure that
200 * largebase+u is odd. Then, step through the sieve in
201 * increments of 2*s
202 */
203 if (u & 0x1)
204 u += s; /* Make largebase+u odd, and u even */
205
206 /* Mark all multiples of 2*s */
207 for (u /= 2; u < largebits; u += s)
208 BIT_SET(LargeSieve, u);
209 }
210
211 /* r = p mod s */
212 r = (2 * r + 1) % s;
213 if (r == 0)
214 u = 0; /* s divides p exactly */
215 else
216 u = s - r; /* p+u is first entry divisible by s */
217
218 if (u < largebits * 4ULL) {
219 /*
220 * The sieve omits p's divisible by 4, so ensure that
221 * largebase+u is not. Then, step through the sieve in
222 * increments of 4*s
223 */
224 while (u & 0x3) {
225 if (SMALL_MAXIMUM - u < s)
226 return;
227 u += s;
228 }
229
230 /* Mark all multiples of 4*s */
231 for (u /= 4; u < largebits; u += s)
232 BIT_SET(LargeSieve, u);
233 }
234 }
235
236 /*
237 * list candidates for Sophie-Germain primes (where q = (p-1)/2)
238 * to standard output.
239 * The list is checked against small known primes (less than 2**30).
240 */
241 int
gen_candidates(FILE * out,u_int32_t memory,u_int32_t power,BIGNUM * start)242 gen_candidates(FILE *out, u_int32_t memory, u_int32_t power, BIGNUM *start)
243 {
244 BIGNUM *q;
245 u_int32_t j, r, s, t;
246 u_int32_t smallwords = TINY_NUMBER >> 6;
247 u_int32_t tinywords = TINY_NUMBER >> 6;
248 time_t time_start, time_stop;
249 u_int32_t i;
250 int ret = 0;
251
252 largememory = memory;
253
254 if (memory != 0 &&
255 (memory < LARGE_MINIMUM || memory > LARGE_MAXIMUM)) {
256 error("Invalid memory amount (min %ld, max %ld)",
257 LARGE_MINIMUM, LARGE_MAXIMUM);
258 return (-1);
259 }
260
261 /*
262 * Set power to the length in bits of the prime to be generated.
263 * This is changed to 1 less than the desired safe prime moduli p.
264 */
265 if (power > TEST_MAXIMUM) {
266 error("Too many bits: %u > %lu", power, TEST_MAXIMUM);
267 return (-1);
268 } else if (power < TEST_MINIMUM) {
269 error("Too few bits: %u < %u", power, TEST_MINIMUM);
270 return (-1);
271 }
272 power--; /* decrement before squaring */
273
274 /*
275 * The density of ordinary primes is on the order of 1/bits, so the
276 * density of safe primes should be about (1/bits)**2. Set test range
277 * to something well above bits**2 to be reasonably sure (but not
278 * guaranteed) of catching at least one safe prime.
279 */
280 largewords = ((power * power) >> (SHIFT_WORD - TEST_POWER));
281
282 /*
283 * Need idea of how much memory is available. We don't have to use all
284 * of it.
285 */
286 if (largememory > LARGE_MAXIMUM) {
287 logit("Limited memory: %u MB; limit %lu MB",
288 largememory, LARGE_MAXIMUM);
289 largememory = LARGE_MAXIMUM;
290 }
291
292 if (largewords <= (largememory << SHIFT_MEGAWORD)) {
293 logit("Increased memory: %u MB; need %u bytes",
294 largememory, (largewords << SHIFT_BYTE));
295 largewords = (largememory << SHIFT_MEGAWORD);
296 } else if (largememory > 0) {
297 logit("Decreased memory: %u MB; want %u bytes",
298 largememory, (largewords << SHIFT_BYTE));
299 largewords = (largememory << SHIFT_MEGAWORD);
300 }
301
302 TinySieve = xcalloc(tinywords, sizeof(u_int32_t));
303 tinybits = tinywords << SHIFT_WORD;
304
305 SmallSieve = xcalloc(smallwords, sizeof(u_int32_t));
306 smallbits = smallwords << SHIFT_WORD;
307
308 /*
309 * dynamically determine available memory
310 */
311 while ((LargeSieve = calloc(largewords, sizeof(u_int32_t))) == NULL)
312 largewords -= (1L << (SHIFT_MEGAWORD - 2)); /* 1/4 MB chunks */
313
314 largebits = largewords << SHIFT_WORD;
315 largenumbers = largebits * 2; /* even numbers excluded */
316
317 /* validation check: count the number of primes tried */
318 largetries = 0;
319 if ((q = BN_new()) == NULL)
320 fatal("BN_new failed");
321
322 /*
323 * Generate random starting point for subprime search, or use
324 * specified parameter.
325 */
326 if ((largebase = BN_new()) == NULL)
327 fatal("BN_new failed");
328 if (start == NULL) {
329 if (BN_rand(largebase, power, 1, 1) == 0)
330 fatal("BN_rand failed");
331 } else {
332 if (BN_copy(largebase, start) == NULL)
333 fatal("BN_copy: failed");
334 }
335
336 /* ensure odd */
337 if (BN_set_bit(largebase, 0) == 0)
338 fatal("BN_set_bit: failed");
339
340 time(&time_start);
341
342 logit("%.24s Sieve next %u plus %u-bit", ctime(&time_start),
343 largenumbers, power);
344 debug2("start point: 0x%s", BN_bn2hex(largebase));
345
346 /*
347 * TinySieve
348 */
349 for (i = 0; i < tinybits; i++) {
350 if (BIT_TEST(TinySieve, i))
351 continue; /* 2*i+3 is composite */
352
353 /* The next tiny prime */
354 t = 2 * i + 3;
355
356 /* Mark all multiples of t */
357 for (j = i + t; j < tinybits; j += t)
358 BIT_SET(TinySieve, j);
359
360 sieve_large(t);
361 }
362
363 /*
364 * Start the small block search at the next possible prime. To avoid
365 * fencepost errors, the last pass is skipped.
366 */
367 for (smallbase = TINY_NUMBER + 3;
368 smallbase < (SMALL_MAXIMUM - TINY_NUMBER);
369 smallbase += TINY_NUMBER) {
370 for (i = 0; i < tinybits; i++) {
371 if (BIT_TEST(TinySieve, i))
372 continue; /* 2*i+3 is composite */
373
374 /* The next tiny prime */
375 t = 2 * i + 3;
376 r = smallbase % t;
377
378 if (r == 0) {
379 s = 0; /* t divides into smallbase exactly */
380 } else {
381 /* smallbase+s is first entry divisible by t */
382 s = t - r;
383 }
384
385 /*
386 * The sieve omits even numbers, so ensure that
387 * smallbase+s is odd. Then, step through the sieve
388 * in increments of 2*t
389 */
390 if (s & 1)
391 s += t; /* Make smallbase+s odd, and s even */
392
393 /* Mark all multiples of 2*t */
394 for (s /= 2; s < smallbits; s += t)
395 BIT_SET(SmallSieve, s);
396 }
397
398 /*
399 * SmallSieve
400 */
401 for (i = 0; i < smallbits; i++) {
402 if (BIT_TEST(SmallSieve, i))
403 continue; /* 2*i+smallbase is composite */
404
405 /* The next small prime */
406 sieve_large((2 * i) + smallbase);
407 }
408
409 memset(SmallSieve, 0, smallwords << SHIFT_BYTE);
410 }
411
412 time(&time_stop);
413
414 logit("%.24s Sieved with %u small primes in %lld seconds",
415 ctime(&time_stop), largetries, (long long)(time_stop - time_start));
416
417 for (j = r = 0; j < largebits; j++) {
418 if (BIT_TEST(LargeSieve, j))
419 continue; /* Definitely composite, skip */
420
421 debug2("test q = largebase+%u", 2 * j);
422 if (BN_set_word(q, 2 * j) == 0)
423 fatal("BN_set_word failed");
424 if (BN_add(q, q, largebase) == 0)
425 fatal("BN_add failed");
426 if (qfileout(out, MODULI_TYPE_SOPHIE_GERMAIN,
427 MODULI_TESTS_SIEVE, largetries,
428 (power - 1) /* MSB */, (0), q) == -1) {
429 ret = -1;
430 break;
431 }
432
433 r++; /* count q */
434 }
435
436 time(&time_stop);
437
438 free(LargeSieve);
439 free(SmallSieve);
440 free(TinySieve);
441
442 logit("%.24s Found %u candidates", ctime(&time_stop), r);
443
444 return (ret);
445 }
446
447 static void
write_checkpoint(char * cpfile,u_int32_t lineno)448 write_checkpoint(char *cpfile, u_int32_t lineno)
449 {
450 FILE *fp;
451 char tmp[PATH_MAX];
452 int r, writeok, closeok;
453
454 r = snprintf(tmp, sizeof(tmp), "%s.XXXXXXXXXX", cpfile);
455 if (r < 0 || r >= PATH_MAX) {
456 logit("write_checkpoint: temp pathname too long");
457 return;
458 }
459 if ((r = mkstemp(tmp)) == -1) {
460 logit("mkstemp(%s): %s", tmp, strerror(errno));
461 return;
462 }
463 if ((fp = fdopen(r, "w")) == NULL) {
464 logit("write_checkpoint: fdopen: %s", strerror(errno));
465 unlink(tmp);
466 close(r);
467 return;
468 }
469 writeok = (fprintf(fp, "%lu\n", (unsigned long)lineno) > 0);
470 closeok = (fclose(fp) == 0);
471 if (writeok && closeok && rename(tmp, cpfile) == 0) {
472 debug3("wrote checkpoint line %lu to '%s'",
473 (unsigned long)lineno, cpfile);
474 } else {
475 logit("failed to write to checkpoint file '%s': %s", cpfile,
476 strerror(errno));
477 (void)unlink(tmp);
478 }
479 }
480
481 static unsigned long
read_checkpoint(char * cpfile)482 read_checkpoint(char *cpfile)
483 {
484 FILE *fp;
485 unsigned long lineno = 0;
486
487 if ((fp = fopen(cpfile, "r")) == NULL)
488 return 0;
489 if (fscanf(fp, "%lu\n", &lineno) < 1)
490 logit("Failed to load checkpoint from '%s'", cpfile);
491 else
492 logit("Loaded checkpoint from '%s' line %lu", cpfile, lineno);
493 fclose(fp);
494 return lineno;
495 }
496
497 static unsigned long
count_lines(FILE * f)498 count_lines(FILE *f)
499 {
500 unsigned long count = 0;
501 char lp[QLINESIZE + 1];
502
503 if (fseek(f, 0, SEEK_SET) != 0) {
504 debug("input file is not seekable");
505 return ULONG_MAX;
506 }
507 while (fgets(lp, QLINESIZE + 1, f) != NULL)
508 count++;
509 rewind(f);
510 debug("input file has %lu lines", count);
511 return count;
512 }
513
514 static char *
fmt_time(time_t seconds)515 fmt_time(time_t seconds)
516 {
517 int day, hr, min;
518 static char buf[128];
519
520 min = (seconds / 60) % 60;
521 hr = (seconds / 60 / 60) % 24;
522 day = seconds / 60 / 60 / 24;
523 if (day > 0)
524 snprintf(buf, sizeof buf, "%dd %d:%02d", day, hr, min);
525 else
526 snprintf(buf, sizeof buf, "%d:%02d", hr, min);
527 return buf;
528 }
529
530 static void
print_progress(unsigned long start_lineno,unsigned long current_lineno,unsigned long end_lineno)531 print_progress(unsigned long start_lineno, unsigned long current_lineno,
532 unsigned long end_lineno)
533 {
534 static time_t time_start, time_prev;
535 time_t time_now, elapsed;
536 unsigned long num_to_process, processed, remaining, percent, eta;
537 double time_per_line;
538 char *eta_str;
539
540 time_now = monotime();
541 if (time_start == 0) {
542 time_start = time_prev = time_now;
543 return;
544 }
545 /* print progress after 1m then once per 5m */
546 if (time_now - time_prev < 5 * 60)
547 return;
548 time_prev = time_now;
549 elapsed = time_now - time_start;
550 processed = current_lineno - start_lineno;
551 remaining = end_lineno - current_lineno;
552 num_to_process = end_lineno - start_lineno;
553 time_per_line = (double)elapsed / processed;
554 /* if we don't know how many we're processing just report count+time */
555 time(&time_now);
556 if (end_lineno == ULONG_MAX) {
557 logit("%.24s processed %lu in %s", ctime(&time_now),
558 processed, fmt_time(elapsed));
559 return;
560 }
561 percent = 100 * processed / num_to_process;
562 eta = time_per_line * remaining;
563 eta_str = xstrdup(fmt_time(eta));
564 logit("%.24s processed %lu of %lu (%lu%%) in %s, ETA %s",
565 ctime(&time_now), processed, num_to_process, percent,
566 fmt_time(elapsed), eta_str);
567 free(eta_str);
568 }
569
570 /*
571 * perform a Miller-Rabin primality test
572 * on the list of candidates
573 * (checking both q and p)
574 * The result is a list of so-call "safe" primes
575 */
576 int
prime_test(FILE * in,FILE * out,u_int32_t trials,u_int32_t generator_wanted,char * checkpoint_file,unsigned long start_lineno,unsigned long num_lines)577 prime_test(FILE *in, FILE *out, u_int32_t trials, u_int32_t generator_wanted,
578 char *checkpoint_file, unsigned long start_lineno, unsigned long num_lines)
579 {
580 BIGNUM *q, *p, *a;
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, is_prime;
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
605 debug2("%.24s Final %u Miller-Rabin trials (%x generator)",
606 ctime(&time_start), trials, generator_wanted);
607
608 if (checkpoint_file != NULL)
609 last_processed = read_checkpoint(checkpoint_file);
610 last_processed = start_lineno = MAXIMUM(last_processed, start_lineno);
611 if (end_lineno == ULONG_MAX)
612 debug("process from line %lu from pipe", last_processed);
613 else
614 debug("process from line %lu to line %lu", last_processed,
615 end_lineno);
616
617 res = 0;
618 lp = xmalloc(QLINESIZE + 1);
619 while (fgets(lp, QLINESIZE + 1, in) != NULL && count_in < end_lineno) {
620 count_in++;
621 if (count_in <= last_processed) {
622 debug3("skipping line %u, before checkpoint or "
623 "specified start line", count_in);
624 continue;
625 }
626 if (checkpoint_file != NULL)
627 write_checkpoint(checkpoint_file, count_in);
628 print_progress(start_lineno, count_in, end_lineno);
629 if (strlen(lp) < 14 || *lp == '!' || *lp == '#') {
630 debug2("%10u: comment or short line", count_in);
631 continue;
632 }
633
634 /* XXX - fragile parser */
635 /* time */
636 cp = &lp[14]; /* (skip) */
637
638 /* type */
639 in_type = strtoul(cp, &cp, 10);
640
641 /* tests */
642 in_tests = strtoul(cp, &cp, 10);
643
644 if (in_tests & MODULI_TESTS_COMPOSITE) {
645 debug2("%10u: known composite", count_in);
646 continue;
647 }
648
649 /* tries */
650 in_tries = strtoul(cp, &cp, 10);
651
652 /* size (most significant bit) */
653 in_size = strtoul(cp, &cp, 10);
654
655 /* generator (hex) */
656 generator_known = strtoul(cp, &cp, 16);
657
658 /* Skip white space */
659 cp += strspn(cp, " ");
660
661 /* modulus (hex) */
662 switch (in_type) {
663 case MODULI_TYPE_SOPHIE_GERMAIN:
664 debug2("%10u: (%u) Sophie-Germain", count_in, in_type);
665 a = q;
666 if (BN_hex2bn(&a, cp) == 0)
667 fatal("BN_hex2bn failed");
668 /* p = 2*q + 1 */
669 if (BN_lshift(p, q, 1) == 0)
670 fatal("BN_lshift failed");
671 if (BN_add_word(p, 1) == 0)
672 fatal("BN_add_word failed");
673 in_size += 1;
674 generator_known = 0;
675 break;
676 case MODULI_TYPE_UNSTRUCTURED:
677 case MODULI_TYPE_SAFE:
678 case MODULI_TYPE_SCHNORR:
679 case MODULI_TYPE_STRONG:
680 case MODULI_TYPE_UNKNOWN:
681 debug2("%10u: (%u)", count_in, in_type);
682 a = p;
683 if (BN_hex2bn(&a, cp) == 0)
684 fatal("BN_hex2bn failed");
685 /* q = (p-1) / 2 */
686 if (BN_rshift(q, p, 1) == 0)
687 fatal("BN_rshift failed");
688 break;
689 default:
690 debug2("Unknown prime type");
691 break;
692 }
693
694 /*
695 * due to earlier inconsistencies in interpretation, check
696 * the proposed bit size.
697 */
698 if ((u_int32_t)BN_num_bits(p) != (in_size + 1)) {
699 debug2("%10u: bit size %u mismatch", count_in, in_size);
700 continue;
701 }
702 if (in_size < QSIZE_MINIMUM) {
703 debug2("%10u: bit size %u too short", count_in, in_size);
704 continue;
705 }
706
707 if (in_tests & MODULI_TESTS_MILLER_RABIN)
708 in_tries += trials;
709 else
710 in_tries = trials;
711
712 /*
713 * guess unknown generator
714 */
715 if (generator_known == 0) {
716 if (BN_mod_word(p, 24) == 11)
717 generator_known = 2;
718 else {
719 u_int32_t r = BN_mod_word(p, 10);
720
721 if (r == 3 || r == 7)
722 generator_known = 5;
723 }
724 }
725 /*
726 * skip tests when desired generator doesn't match
727 */
728 if (generator_wanted > 0 &&
729 generator_wanted != generator_known) {
730 debug2("%10u: generator %d != %d",
731 count_in, generator_known, generator_wanted);
732 continue;
733 }
734
735 /*
736 * Primes with no known generator are useless for DH, so
737 * skip those.
738 */
739 if (generator_known == 0) {
740 debug2("%10u: no known generator", count_in);
741 continue;
742 }
743
744 count_possible++;
745
746 /*
747 * The (1/4)^N performance bound on Miller-Rabin is
748 * extremely pessimistic, so don't spend a lot of time
749 * really verifying that q is prime until after we know
750 * that p is also prime. A single pass will weed out the
751 * vast majority of composite q's.
752 */
753 is_prime = BN_is_prime_ex(q, 1, NULL, NULL);
754 if (is_prime < 0)
755 fatal("BN_is_prime_ex failed");
756 if (is_prime == 0) {
757 debug("%10u: q failed first possible prime test",
758 count_in);
759 continue;
760 }
761
762 /*
763 * q is possibly prime, so go ahead and really make sure
764 * that p is prime. If it is, then we can go back and do
765 * the same for q. If p is composite, chances are that
766 * will show up on the first Rabin-Miller iteration so it
767 * doesn't hurt to specify a high iteration count.
768 */
769 is_prime = BN_is_prime_ex(p, trials, NULL, NULL);
770 if (is_prime < 0)
771 fatal("BN_is_prime_ex failed");
772 if (is_prime == 0) {
773 debug("%10u: p is not prime", count_in);
774 continue;
775 }
776 debug("%10u: p is almost certainly prime", count_in);
777
778 /* recheck q more rigorously */
779 is_prime = BN_is_prime_ex(q, trials - 1, NULL, NULL);
780 if (is_prime < 0)
781 fatal("BN_is_prime_ex failed");
782 if (is_prime == 0) {
783 debug("%10u: q is not prime", count_in);
784 continue;
785 }
786 debug("%10u: q is almost certainly prime", count_in);
787
788 if (qfileout(out, MODULI_TYPE_SAFE,
789 in_tests | MODULI_TESTS_MILLER_RABIN,
790 in_tries, in_size, generator_known, p)) {
791 res = -1;
792 break;
793 }
794
795 count_out++;
796 }
797
798 time(&time_stop);
799 free(lp);
800 BN_free(p);
801 BN_free(q);
802
803 if (checkpoint_file != NULL)
804 unlink(checkpoint_file);
805
806 logit("%.24s Found %u safe primes of %u candidates in %ld seconds",
807 ctime(&time_stop), count_out, count_possible,
808 (long) (time_stop - time_start));
809
810 return (res);
811 }
812