1 /* $OpenBSD: moduli.c,v 1.31 2016/09/12 01:22:38 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 "includes.h"
41
42 #ifdef WITH_OPENSSL
43
44 #include <sys/types.h>
45
46 #include <openssl/bn.h>
47 #include <openssl/dh.h>
48
49 #include <errno.h>
50 #include <stdio.h>
51 #include <stdlib.h>
52 #include <string.h>
53 #include <stdarg.h>
54 #include <time.h>
55 #include <unistd.h>
56 #include <limits.h>
57
58 #include "xmalloc.h"
59 #include "dh.h"
60 #include "log.h"
61 #include "misc.h"
62
63 #include "openbsd-compat/openssl-compat.h"
64
65 /*
66 * File output defines
67 */
68
69 /* need line long enough for largest moduli plus headers */
70 #define QLINESIZE (100+8192)
71
72 /*
73 * Size: decimal.
74 * Specifies the number of the most significant bit (0 to M).
75 * WARNING: internally, usually 1 to N.
76 */
77 #define QSIZE_MINIMUM (511)
78
79 /*
80 * Prime sieving defines
81 */
82
83 /* Constant: assuming 8 bit bytes and 32 bit words */
84 #define SHIFT_BIT (3)
85 #define SHIFT_BYTE (2)
86 #define SHIFT_WORD (SHIFT_BIT+SHIFT_BYTE)
87 #define SHIFT_MEGABYTE (20)
88 #define SHIFT_MEGAWORD (SHIFT_MEGABYTE-SHIFT_BYTE)
89
90 /*
91 * Using virtual memory can cause thrashing. This should be the largest
92 * number that is supported without a large amount of disk activity --
93 * that would increase the run time from hours to days or weeks!
94 */
95 #define LARGE_MINIMUM (8UL) /* megabytes */
96
97 /*
98 * Do not increase this number beyond the unsigned integer bit size.
99 * Due to a multiple of 4, it must be LESS than 128 (yielding 2**30 bits).
100 */
101 #define LARGE_MAXIMUM (127UL) /* megabytes */
102
103 /*
104 * Constant: when used with 32-bit integers, the largest sieve prime
105 * has to be less than 2**32.
106 */
107 #define SMALL_MAXIMUM (0xffffffffUL)
108
109 /* Constant: can sieve all primes less than 2**32, as 65537**2 > 2**32-1. */
110 #define TINY_NUMBER (1UL<<16)
111
112 /* Ensure enough bit space for testing 2*q. */
113 #define TEST_MAXIMUM (1UL<<16)
114 #define TEST_MINIMUM (QSIZE_MINIMUM + 1)
115 /* real TEST_MINIMUM (1UL << (SHIFT_WORD - TEST_POWER)) */
116 #define TEST_POWER (3) /* 2**n, n < SHIFT_WORD */
117
118 /* bit operations on 32-bit words */
119 #define BIT_CLEAR(a,n) ((a)[(n)>>SHIFT_WORD] &= ~(1L << ((n) & 31)))
120 #define BIT_SET(a,n) ((a)[(n)>>SHIFT_WORD] |= (1L << ((n) & 31)))
121 #define BIT_TEST(a,n) ((a)[(n)>>SHIFT_WORD] & (1L << ((n) & 31)))
122
123 /*
124 * Prime testing defines
125 */
126
127 /* Minimum number of primality tests to perform */
128 #define TRIAL_MINIMUM (4)
129
130 /*
131 * Sieving data (XXX - move to struct)
132 */
133
134 /* sieve 2**16 */
135 static u_int32_t *TinySieve, tinybits;
136
137 /* sieve 2**30 in 2**16 parts */
138 static u_int32_t *SmallSieve, smallbits, smallbase;
139
140 /* sieve relative to the initial value */
141 static u_int32_t *LargeSieve, largewords, largetries, largenumbers;
142 static u_int32_t largebits, largememory; /* megabytes */
143 static BIGNUM *largebase;
144
145 int gen_candidates(FILE *, u_int32_t, u_int32_t, BIGNUM *);
146 int prime_test(FILE *, FILE *, u_int32_t, u_int32_t, char *, unsigned long,
147 unsigned long);
148
149 /*
150 * print moduli out in consistent form,
151 */
152 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)153 qfileout(FILE * ofile, u_int32_t otype, u_int32_t otests, u_int32_t otries,
154 u_int32_t osize, u_int32_t ogenerator, BIGNUM * omodulus)
155 {
156 struct tm *gtm;
157 time_t time_now;
158 int res;
159
160 time(&time_now);
161 gtm = gmtime(&time_now);
162
163 res = fprintf(ofile, "%04d%02d%02d%02d%02d%02d %u %u %u %u %x ",
164 gtm->tm_year + 1900, gtm->tm_mon + 1, gtm->tm_mday,
165 gtm->tm_hour, gtm->tm_min, gtm->tm_sec,
166 otype, otests, otries, osize, ogenerator);
167
168 if (res < 0)
169 return (-1);
170
171 if (BN_print_fp(ofile, omodulus) < 1)
172 return (-1);
173
174 res = fprintf(ofile, "\n");
175 fflush(ofile);
176
177 return (res > 0 ? 0 : -1);
178 }
179
180
181 /*
182 ** Sieve p's and q's with small factors
183 */
184 static void
sieve_large(u_int32_t s)185 sieve_large(u_int32_t s)
186 {
187 u_int32_t r, u;
188
189 debug3("sieve_large %u", s);
190 largetries++;
191 /* r = largebase mod s */
192 r = BN_mod_word(largebase, s);
193 if (r == 0)
194 u = 0; /* s divides into largebase exactly */
195 else
196 u = s - r; /* largebase+u is first entry divisible by s */
197
198 if (u < largebits * 2) {
199 /*
200 * The sieve omits p's and q's divisible by 2, so ensure that
201 * largebase+u is odd. Then, step through the sieve in
202 * increments of 2*s
203 */
204 if (u & 0x1)
205 u += s; /* Make largebase+u odd, and u even */
206
207 /* Mark all multiples of 2*s */
208 for (u /= 2; u < largebits; u += s)
209 BIT_SET(LargeSieve, u);
210 }
211
212 /* r = p mod s */
213 r = (2 * r + 1) % s;
214 if (r == 0)
215 u = 0; /* s divides p exactly */
216 else
217 u = s - r; /* p+u is first entry divisible by s */
218
219 if (u < largebits * 4) {
220 /*
221 * The sieve omits p's divisible by 4, so ensure that
222 * largebase+u is not. Then, step through the sieve in
223 * increments of 4*s
224 */
225 while (u & 0x3) {
226 if (SMALL_MAXIMUM - u < s)
227 return;
228 u += s;
229 }
230
231 /* Mark all multiples of 4*s */
232 for (u /= 4; u < largebits; u += s)
233 BIT_SET(LargeSieve, u);
234 }
235 }
236
237 /*
238 * list candidates for Sophie-Germain primes (where q = (p-1)/2)
239 * to standard output.
240 * The list is checked against small known primes (less than 2**30).
241 */
242 int
gen_candidates(FILE * out,u_int32_t memory,u_int32_t power,BIGNUM * start)243 gen_candidates(FILE *out, u_int32_t memory, u_int32_t power, BIGNUM *start)
244 {
245 BIGNUM *q;
246 u_int32_t j, r, s, t;
247 u_int32_t smallwords = TINY_NUMBER >> 6;
248 u_int32_t tinywords = TINY_NUMBER >> 6;
249 time_t time_start, time_stop;
250 u_int32_t i;
251 int ret = 0;
252
253 largememory = memory;
254
255 if (memory != 0 &&
256 (memory < LARGE_MINIMUM || memory > LARGE_MAXIMUM)) {
257 error("Invalid memory amount (min %ld, max %ld)",
258 LARGE_MINIMUM, LARGE_MAXIMUM);
259 return (-1);
260 }
261
262 /*
263 * Set power to the length in bits of the prime to be generated.
264 * This is changed to 1 less than the desired safe prime moduli p.
265 */
266 if (power > TEST_MAXIMUM) {
267 error("Too many bits: %u > %lu", power, TEST_MAXIMUM);
268 return (-1);
269 } else if (power < TEST_MINIMUM) {
270 error("Too few bits: %u < %u", power, TEST_MINIMUM);
271 return (-1);
272 }
273 power--; /* decrement before squaring */
274
275 /*
276 * The density of ordinary primes is on the order of 1/bits, so the
277 * density of safe primes should be about (1/bits)**2. Set test range
278 * to something well above bits**2 to be reasonably sure (but not
279 * guaranteed) of catching at least one safe prime.
280 */
281 largewords = ((power * power) >> (SHIFT_WORD - TEST_POWER));
282
283 /*
284 * Need idea of how much memory is available. We don't have to use all
285 * of it.
286 */
287 if (largememory > LARGE_MAXIMUM) {
288 logit("Limited memory: %u MB; limit %lu MB",
289 largememory, LARGE_MAXIMUM);
290 largememory = LARGE_MAXIMUM;
291 }
292
293 if (largewords <= (largememory << SHIFT_MEGAWORD)) {
294 logit("Increased memory: %u MB; need %u bytes",
295 largememory, (largewords << SHIFT_BYTE));
296 largewords = (largememory << SHIFT_MEGAWORD);
297 } else if (largememory > 0) {
298 logit("Decreased memory: %u MB; want %u bytes",
299 largememory, (largewords << SHIFT_BYTE));
300 largewords = (largememory << SHIFT_MEGAWORD);
301 }
302
303 TinySieve = xcalloc(tinywords, sizeof(u_int32_t));
304 tinybits = tinywords << SHIFT_WORD;
305
306 SmallSieve = xcalloc(smallwords, sizeof(u_int32_t));
307 smallbits = smallwords << SHIFT_WORD;
308
309 /*
310 * dynamically determine available memory
311 */
312 while ((LargeSieve = calloc(largewords, sizeof(u_int32_t))) == NULL)
313 largewords -= (1L << (SHIFT_MEGAWORD - 2)); /* 1/4 MB chunks */
314
315 largebits = largewords << SHIFT_WORD;
316 largenumbers = largebits * 2; /* even numbers excluded */
317
318 /* validation check: count the number of primes tried */
319 largetries = 0;
320 if ((q = BN_new()) == NULL)
321 fatal("BN_new failed");
322
323 /*
324 * Generate random starting point for subprime search, or use
325 * specified parameter.
326 */
327 if ((largebase = BN_new()) == NULL)
328 fatal("BN_new failed");
329 if (start == NULL) {
330 if (BN_rand(largebase, power, 1, 1) == 0)
331 fatal("BN_rand failed");
332 } else {
333 if (BN_copy(largebase, start) == NULL)
334 fatal("BN_copy: failed");
335 }
336
337 /* ensure odd */
338 if (BN_set_bit(largebase, 0) == 0)
339 fatal("BN_set_bit: failed");
340
341 time(&time_start);
342
343 logit("%.24s Sieve next %u plus %u-bit", ctime(&time_start),
344 largenumbers, power);
345 debug2("start point: 0x%s", BN_bn2hex(largebase));
346
347 /*
348 * TinySieve
349 */
350 for (i = 0; i < tinybits; i++) {
351 if (BIT_TEST(TinySieve, i))
352 continue; /* 2*i+3 is composite */
353
354 /* The next tiny prime */
355 t = 2 * i + 3;
356
357 /* Mark all multiples of t */
358 for (j = i + t; j < tinybits; j += t)
359 BIT_SET(TinySieve, j);
360
361 sieve_large(t);
362 }
363
364 /*
365 * Start the small block search at the next possible prime. To avoid
366 * fencepost errors, the last pass is skipped.
367 */
368 for (smallbase = TINY_NUMBER + 3;
369 smallbase < (SMALL_MAXIMUM - TINY_NUMBER);
370 smallbase += TINY_NUMBER) {
371 for (i = 0; i < tinybits; i++) {
372 if (BIT_TEST(TinySieve, i))
373 continue; /* 2*i+3 is composite */
374
375 /* The next tiny prime */
376 t = 2 * i + 3;
377 r = smallbase % t;
378
379 if (r == 0) {
380 s = 0; /* t divides into smallbase exactly */
381 } else {
382 /* smallbase+s is first entry divisible by t */
383 s = t - r;
384 }
385
386 /*
387 * The sieve omits even numbers, so ensure that
388 * smallbase+s is odd. Then, step through the sieve
389 * in increments of 2*t
390 */
391 if (s & 1)
392 s += t; /* Make smallbase+s odd, and s even */
393
394 /* Mark all multiples of 2*t */
395 for (s /= 2; s < smallbits; s += t)
396 BIT_SET(SmallSieve, s);
397 }
398
399 /*
400 * SmallSieve
401 */
402 for (i = 0; i < smallbits; i++) {
403 if (BIT_TEST(SmallSieve, i))
404 continue; /* 2*i+smallbase is composite */
405
406 /* The next small prime */
407 sieve_large((2 * i) + smallbase);
408 }
409
410 memset(SmallSieve, 0, smallwords << SHIFT_BYTE);
411 }
412
413 time(&time_stop);
414
415 logit("%.24s Sieved with %u small primes in %ld seconds",
416 ctime(&time_stop), largetries, (long) (time_stop - time_start));
417
418 for (j = r = 0; j < largebits; j++) {
419 if (BIT_TEST(LargeSieve, j))
420 continue; /* Definitely composite, skip */
421
422 debug2("test q = largebase+%u", 2 * j);
423 if (BN_set_word(q, 2 * j) == 0)
424 fatal("BN_set_word failed");
425 if (BN_add(q, q, largebase) == 0)
426 fatal("BN_add failed");
427 if (qfileout(out, MODULI_TYPE_SOPHIE_GERMAIN,
428 MODULI_TESTS_SIEVE, largetries,
429 (power - 1) /* MSB */, (0), q) == -1) {
430 ret = -1;
431 break;
432 }
433
434 r++; /* count q */
435 }
436
437 time(&time_stop);
438
439 free(LargeSieve);
440 free(SmallSieve);
441 free(TinySieve);
442
443 logit("%.24s Found %u candidates", ctime(&time_stop), r);
444
445 return (ret);
446 }
447
448 static void
write_checkpoint(char * cpfile,u_int32_t lineno)449 write_checkpoint(char *cpfile, u_int32_t lineno)
450 {
451 FILE *fp;
452 char tmp[PATH_MAX];
453 int r;
454
455 r = snprintf(tmp, sizeof(tmp), "%s.XXXXXXXXXX", cpfile);
456 if (r == -1 || r >= PATH_MAX) {
457 logit("write_checkpoint: temp pathname too long");
458 return;
459 }
460 if ((r = mkstemp(tmp)) == -1) {
461 logit("mkstemp(%s): %s", tmp, strerror(errno));
462 return;
463 }
464 if ((fp = fdopen(r, "w")) == NULL) {
465 logit("write_checkpoint: fdopen: %s", strerror(errno));
466 unlink(tmp);
467 close(r);
468 return;
469 }
470 if (fprintf(fp, "%lu\n", (unsigned long)lineno) > 0 && fclose(fp) == 0
471 && 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 }
478
479 static unsigned long
read_checkpoint(char * cpfile)480 read_checkpoint(char *cpfile)
481 {
482 FILE *fp;
483 unsigned long lineno = 0;
484
485 if ((fp = fopen(cpfile, "r")) == NULL)
486 return 0;
487 if (fscanf(fp, "%lu\n", &lineno) < 1)
488 logit("Failed to load checkpoint from '%s'", cpfile);
489 else
490 logit("Loaded checkpoint from '%s' line %lu", cpfile, lineno);
491 fclose(fp);
492 return lineno;
493 }
494
495 static unsigned long
count_lines(FILE * f)496 count_lines(FILE *f)
497 {
498 unsigned long count = 0;
499 char lp[QLINESIZE + 1];
500
501 if (fseek(f, 0, SEEK_SET) != 0) {
502 debug("input file is not seekable");
503 return ULONG_MAX;
504 }
505 while (fgets(lp, QLINESIZE + 1, f) != NULL)
506 count++;
507 rewind(f);
508 debug("input file has %lu lines", count);
509 return count;
510 }
511
512 static char *
fmt_time(time_t seconds)513 fmt_time(time_t seconds)
514 {
515 int day, hr, min;
516 static char buf[128];
517
518 min = (seconds / 60) % 60;
519 hr = (seconds / 60 / 60) % 24;
520 day = seconds / 60 / 60 / 24;
521 if (day > 0)
522 snprintf(buf, sizeof buf, "%dd %d:%02d", day, hr, min);
523 else
524 snprintf(buf, sizeof buf, "%d:%02d", hr, min);
525 return buf;
526 }
527
528 static void
print_progress(unsigned long start_lineno,unsigned long current_lineno,unsigned long end_lineno)529 print_progress(unsigned long start_lineno, unsigned long current_lineno,
530 unsigned long end_lineno)
531 {
532 static time_t time_start, time_prev;
533 time_t time_now, elapsed;
534 unsigned long num_to_process, processed, remaining, percent, eta;
535 double time_per_line;
536 char *eta_str;
537
538 time_now = monotime();
539 if (time_start == 0) {
540 time_start = time_prev = time_now;
541 return;
542 }
543 /* print progress after 1m then once per 5m */
544 if (time_now - time_prev < 5 * 60)
545 return;
546 time_prev = time_now;
547 elapsed = time_now - time_start;
548 processed = current_lineno - start_lineno;
549 remaining = end_lineno - current_lineno;
550 num_to_process = end_lineno - start_lineno;
551 time_per_line = (double)elapsed / processed;
552 /* if we don't know how many we're processing just report count+time */
553 time(&time_now);
554 if (end_lineno == ULONG_MAX) {
555 logit("%.24s processed %lu in %s", ctime(&time_now),
556 processed, fmt_time(elapsed));
557 return;
558 }
559 percent = 100 * processed / num_to_process;
560 eta = time_per_line * remaining;
561 eta_str = xstrdup(fmt_time(eta));
562 logit("%.24s processed %lu of %lu (%lu%%) in %s, ETA %s",
563 ctime(&time_now), processed, num_to_process, percent,
564 fmt_time(elapsed), eta_str);
565 free(eta_str);
566 }
567
568 /*
569 * perform a Miller-Rabin primality test
570 * on the list of candidates
571 * (checking both q and p)
572 * The result is a list of so-call "safe" primes
573 */
574 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)575 prime_test(FILE *in, FILE *out, u_int32_t trials, u_int32_t generator_wanted,
576 char *checkpoint_file, unsigned long start_lineno, unsigned long num_lines)
577 {
578 BIGNUM *q, *p, *a;
579 BN_CTX *ctx;
580 char *cp, *lp;
581 u_int32_t count_in = 0, count_out = 0, count_possible = 0;
582 u_int32_t generator_known, in_tests, in_tries, in_type, in_size;
583 unsigned long last_processed = 0, end_lineno;
584 time_t time_start, time_stop;
585 int res;
586
587 if (trials < TRIAL_MINIMUM) {
588 error("Minimum primality trials is %d", TRIAL_MINIMUM);
589 return (-1);
590 }
591
592 if (num_lines == 0)
593 end_lineno = count_lines(in);
594 else
595 end_lineno = start_lineno + num_lines;
596
597 time(&time_start);
598
599 if ((p = BN_new()) == NULL)
600 fatal("BN_new failed");
601 if ((q = BN_new()) == NULL)
602 fatal("BN_new failed");
603 if ((ctx = BN_CTX_new()) == NULL)
604 fatal("BN_CTX_new failed");
605
606 debug2("%.24s Final %u Miller-Rabin trials (%x generator)",
607 ctime(&time_start), trials, generator_wanted);
608
609 if (checkpoint_file != NULL)
610 last_processed = read_checkpoint(checkpoint_file);
611 last_processed = start_lineno = MAXIMUM(last_processed, start_lineno);
612 if (end_lineno == ULONG_MAX)
613 debug("process from line %lu from pipe", last_processed);
614 else
615 debug("process from line %lu to line %lu", last_processed,
616 end_lineno);
617
618 res = 0;
619 lp = xmalloc(QLINESIZE + 1);
620 while (fgets(lp, QLINESIZE + 1, in) != NULL && count_in < end_lineno) {
621 count_in++;
622 if (count_in <= last_processed) {
623 debug3("skipping line %u, before checkpoint or "
624 "specified start line", count_in);
625 continue;
626 }
627 if (checkpoint_file != NULL)
628 write_checkpoint(checkpoint_file, count_in);
629 print_progress(start_lineno, count_in, end_lineno);
630 if (strlen(lp) < 14 || *lp == '!' || *lp == '#') {
631 debug2("%10u: comment or short line", count_in);
632 continue;
633 }
634
635 /* XXX - fragile parser */
636 /* time */
637 cp = &lp[14]; /* (skip) */
638
639 /* type */
640 in_type = strtoul(cp, &cp, 10);
641
642 /* tests */
643 in_tests = strtoul(cp, &cp, 10);
644
645 if (in_tests & MODULI_TESTS_COMPOSITE) {
646 debug2("%10u: known composite", count_in);
647 continue;
648 }
649
650 /* tries */
651 in_tries = strtoul(cp, &cp, 10);
652
653 /* size (most significant bit) */
654 in_size = strtoul(cp, &cp, 10);
655
656 /* generator (hex) */
657 generator_known = strtoul(cp, &cp, 16);
658
659 /* Skip white space */
660 cp += strspn(cp, " ");
661
662 /* modulus (hex) */
663 switch (in_type) {
664 case MODULI_TYPE_SOPHIE_GERMAIN:
665 debug2("%10u: (%u) Sophie-Germain", count_in, in_type);
666 a = q;
667 if (BN_hex2bn(&a, cp) == 0)
668 fatal("BN_hex2bn failed");
669 /* p = 2*q + 1 */
670 if (BN_lshift(p, q, 1) == 0)
671 fatal("BN_lshift failed");
672 if (BN_add_word(p, 1) == 0)
673 fatal("BN_add_word failed");
674 in_size += 1;
675 generator_known = 0;
676 break;
677 case MODULI_TYPE_UNSTRUCTURED:
678 case MODULI_TYPE_SAFE:
679 case MODULI_TYPE_SCHNORR:
680 case MODULI_TYPE_STRONG:
681 case MODULI_TYPE_UNKNOWN:
682 debug2("%10u: (%u)", count_in, in_type);
683 a = p;
684 if (BN_hex2bn(&a, cp) == 0)
685 fatal("BN_hex2bn failed");
686 /* q = (p-1) / 2 */
687 if (BN_rshift(q, p, 1) == 0)
688 fatal("BN_rshift failed");
689 break;
690 default:
691 debug2("Unknown prime type");
692 break;
693 }
694
695 /*
696 * due to earlier inconsistencies in interpretation, check
697 * the proposed bit size.
698 */
699 if ((u_int32_t)BN_num_bits(p) != (in_size + 1)) {
700 debug2("%10u: bit size %u mismatch", count_in, in_size);
701 continue;
702 }
703 if (in_size < QSIZE_MINIMUM) {
704 debug2("%10u: bit size %u too short", count_in, in_size);
705 continue;
706 }
707
708 if (in_tests & MODULI_TESTS_MILLER_RABIN)
709 in_tries += trials;
710 else
711 in_tries = trials;
712
713 /*
714 * guess unknown generator
715 */
716 if (generator_known == 0) {
717 if (BN_mod_word(p, 24) == 11)
718 generator_known = 2;
719 else if (BN_mod_word(p, 12) == 5)
720 generator_known = 3;
721 else {
722 u_int32_t r = BN_mod_word(p, 10);
723
724 if (r == 3 || r == 7)
725 generator_known = 5;
726 }
727 }
728 /*
729 * skip tests when desired generator doesn't match
730 */
731 if (generator_wanted > 0 &&
732 generator_wanted != generator_known) {
733 debug2("%10u: generator %d != %d",
734 count_in, generator_known, generator_wanted);
735 continue;
736 }
737
738 /*
739 * Primes with no known generator are useless for DH, so
740 * skip those.
741 */
742 if (generator_known == 0) {
743 debug2("%10u: no known generator", count_in);
744 continue;
745 }
746
747 count_possible++;
748
749 /*
750 * The (1/4)^N performance bound on Miller-Rabin is
751 * extremely pessimistic, so don't spend a lot of time
752 * really verifying that q is prime until after we know
753 * that p is also prime. A single pass will weed out the
754 * vast majority of composite q's.
755 */
756 if (BN_is_prime_ex(q, 1, ctx, NULL) <= 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 if (!BN_is_prime_ex(p, trials, ctx, NULL)) {
770 debug("%10u: p is not prime", count_in);
771 continue;
772 }
773 debug("%10u: p is almost certainly prime", count_in);
774
775 /* recheck q more rigorously */
776 if (!BN_is_prime_ex(q, trials - 1, ctx, NULL)) {
777 debug("%10u: q is not prime", count_in);
778 continue;
779 }
780 debug("%10u: q is almost certainly prime", count_in);
781
782 if (qfileout(out, MODULI_TYPE_SAFE,
783 in_tests | MODULI_TESTS_MILLER_RABIN,
784 in_tries, in_size, generator_known, p)) {
785 res = -1;
786 break;
787 }
788
789 count_out++;
790 }
791
792 time(&time_stop);
793 free(lp);
794 BN_free(p);
795 BN_free(q);
796 BN_CTX_free(ctx);
797
798 if (checkpoint_file != NULL)
799 unlink(checkpoint_file);
800
801 logit("%.24s Found %u safe primes of %u candidates in %ld seconds",
802 ctime(&time_stop), count_out, count_possible,
803 (long) (time_stop - time_start));
804
805 return (res);
806 }
807
808 #endif /* WITH_OPENSSL */
809