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