Annotation of src/usr.bin/ssh/moduli.c, Revision 1.24
1.24 ! stsp 1: /* $OpenBSD: moduli.c,v 1.23 2011/10/16 11:02:46 dtucker Exp $ */
1.1 djm 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:
1.24 ! stsp 40: #include <sys/param.h>
1.14 stevesk 41: #include <sys/types.h>
42:
43: #include <openssl/bn.h>
1.21 djm 44: #include <openssl/dh.h>
1.14 stevesk 45:
1.24 ! stsp 46: #include <errno.h>
1.17 stevesk 47: #include <stdio.h>
1.16 stevesk 48: #include <stdlib.h>
1.15 stevesk 49: #include <string.h>
1.18 deraadt 50: #include <stdarg.h>
1.14 stevesk 51: #include <time.h>
1.23 dtucker 52: #include <unistd.h>
1.14 stevesk 53:
1.1 djm 54: #include "xmalloc.h"
1.21 djm 55: #include "dh.h"
1.1 djm 56: #include "log.h"
57:
58: /*
59: * File output defines
60: */
61:
62: /* need line long enough for largest moduli plus headers */
1.9 deraadt 63: #define QLINESIZE (100+8192)
1.1 djm 64:
1.5 djm 65: /*
66: * Size: decimal.
1.1 djm 67: * Specifies the number of the most significant bit (0 to M).
1.5 djm 68: * WARNING: internally, usually 1 to N.
1.1 djm 69: */
1.9 deraadt 70: #define QSIZE_MINIMUM (511)
1.1 djm 71:
72: /*
73: * Prime sieving defines
74: */
75:
76: /* Constant: assuming 8 bit bytes and 32 bit words */
1.9 deraadt 77: #define SHIFT_BIT (3)
78: #define SHIFT_BYTE (2)
79: #define SHIFT_WORD (SHIFT_BIT+SHIFT_BYTE)
80: #define SHIFT_MEGABYTE (20)
81: #define SHIFT_MEGAWORD (SHIFT_MEGABYTE-SHIFT_BYTE)
1.1 djm 82:
83: /*
1.7 djm 84: * Using virtual memory can cause thrashing. This should be the largest
85: * number that is supported without a large amount of disk activity --
86: * that would increase the run time from hours to days or weeks!
87: */
1.9 deraadt 88: #define LARGE_MINIMUM (8UL) /* megabytes */
1.7 djm 89:
90: /*
91: * Do not increase this number beyond the unsigned integer bit size.
92: * Due to a multiple of 4, it must be LESS than 128 (yielding 2**30 bits).
93: */
1.9 deraadt 94: #define LARGE_MAXIMUM (127UL) /* megabytes */
1.7 djm 95:
96: /*
1.1 djm 97: * Constant: when used with 32-bit integers, the largest sieve prime
98: * has to be less than 2**32.
99: */
1.9 deraadt 100: #define SMALL_MAXIMUM (0xffffffffUL)
1.1 djm 101:
102: /* Constant: can sieve all primes less than 2**32, as 65537**2 > 2**32-1. */
1.9 deraadt 103: #define TINY_NUMBER (1UL<<16)
1.1 djm 104:
105: /* Ensure enough bit space for testing 2*q. */
1.12 djm 106: #define TEST_MAXIMUM (1UL<<16)
107: #define TEST_MINIMUM (QSIZE_MINIMUM + 1)
108: /* real TEST_MINIMUM (1UL << (SHIFT_WORD - TEST_POWER)) */
109: #define TEST_POWER (3) /* 2**n, n < SHIFT_WORD */
1.1 djm 110:
111: /* bit operations on 32-bit words */
1.12 djm 112: #define BIT_CLEAR(a,n) ((a)[(n)>>SHIFT_WORD] &= ~(1L << ((n) & 31)))
113: #define BIT_SET(a,n) ((a)[(n)>>SHIFT_WORD] |= (1L << ((n) & 31)))
114: #define BIT_TEST(a,n) ((a)[(n)>>SHIFT_WORD] & (1L << ((n) & 31)))
1.1 djm 115:
116: /*
117: * Prime testing defines
118: */
119:
1.7 djm 120: /* Minimum number of primality tests to perform */
1.12 djm 121: #define TRIAL_MINIMUM (4)
1.7 djm 122:
1.1 djm 123: /*
124: * Sieving data (XXX - move to struct)
125: */
126:
127: /* sieve 2**16 */
128: static u_int32_t *TinySieve, tinybits;
129:
130: /* sieve 2**30 in 2**16 parts */
131: static u_int32_t *SmallSieve, smallbits, smallbase;
132:
133: /* sieve relative to the initial value */
134: static u_int32_t *LargeSieve, largewords, largetries, largenumbers;
135: static u_int32_t largebits, largememory; /* megabytes */
136: static BIGNUM *largebase;
137:
1.11 avsm 138: int gen_candidates(FILE *, u_int32_t, u_int32_t, BIGNUM *);
1.23 dtucker 139: int prime_test(FILE *, FILE *, u_int32_t, u_int32_t, char *);
1.1 djm 140:
141: /*
142: * print moduli out in consistent form,
143: */
144: static int
145: qfileout(FILE * ofile, u_int32_t otype, u_int32_t otests, u_int32_t otries,
146: u_int32_t osize, u_int32_t ogenerator, BIGNUM * omodulus)
147: {
148: struct tm *gtm;
149: time_t time_now;
150: int res;
151:
152: time(&time_now);
153: gtm = gmtime(&time_now);
1.2 djm 154:
1.1 djm 155: res = fprintf(ofile, "%04d%02d%02d%02d%02d%02d %u %u %u %u %x ",
156: gtm->tm_year + 1900, gtm->tm_mon + 1, gtm->tm_mday,
157: gtm->tm_hour, gtm->tm_min, gtm->tm_sec,
158: otype, otests, otries, osize, ogenerator);
159:
160: if (res < 0)
161: return (-1);
162:
163: if (BN_print_fp(ofile, omodulus) < 1)
164: return (-1);
165:
166: res = fprintf(ofile, "\n");
167: fflush(ofile);
168:
169: return (res > 0 ? 0 : -1);
170: }
171:
172:
173: /*
174: ** Sieve p's and q's with small factors
175: */
176: static void
177: sieve_large(u_int32_t s)
178: {
179: u_int32_t r, u;
180:
1.5 djm 181: debug3("sieve_large %u", s);
1.1 djm 182: largetries++;
183: /* r = largebase mod s */
184: r = BN_mod_word(largebase, s);
185: if (r == 0)
186: u = 0; /* s divides into largebase exactly */
187: else
188: u = s - r; /* largebase+u is first entry divisible by s */
189:
190: if (u < largebits * 2) {
191: /*
192: * The sieve omits p's and q's divisible by 2, so ensure that
193: * largebase+u is odd. Then, step through the sieve in
194: * increments of 2*s
195: */
196: if (u & 0x1)
197: u += s; /* Make largebase+u odd, and u even */
198:
199: /* Mark all multiples of 2*s */
200: for (u /= 2; u < largebits; u += s)
201: BIT_SET(LargeSieve, u);
202: }
203:
204: /* r = p mod s */
205: r = (2 * r + 1) % s;
206: if (r == 0)
207: u = 0; /* s divides p exactly */
208: else
209: u = s - r; /* p+u is first entry divisible by s */
210:
211: if (u < largebits * 4) {
212: /*
213: * The sieve omits p's divisible by 4, so ensure that
214: * largebase+u is not. Then, step through the sieve in
215: * increments of 4*s
216: */
217: while (u & 0x3) {
218: if (SMALL_MAXIMUM - u < s)
219: return;
220: u += s;
221: }
222:
223: /* Mark all multiples of 4*s */
224: for (u /= 4; u < largebits; u += s)
225: BIT_SET(LargeSieve, u);
226: }
227: }
228:
229: /*
1.6 djm 230: * list candidates for Sophie-Germain primes (where q = (p-1)/2)
1.1 djm 231: * to standard output.
232: * The list is checked against small known primes (less than 2**30).
233: */
234: int
1.11 avsm 235: gen_candidates(FILE *out, u_int32_t memory, u_int32_t power, BIGNUM *start)
1.1 djm 236: {
237: BIGNUM *q;
238: u_int32_t j, r, s, t;
239: u_int32_t smallwords = TINY_NUMBER >> 6;
240: u_int32_t tinywords = TINY_NUMBER >> 6;
241: time_t time_start, time_stop;
1.11 avsm 242: u_int32_t i;
243: int ret = 0;
1.1 djm 244:
245: largememory = memory;
246:
1.7 djm 247: if (memory != 0 &&
1.12 djm 248: (memory < LARGE_MINIMUM || memory > LARGE_MAXIMUM)) {
1.7 djm 249: error("Invalid memory amount (min %ld, max %ld)",
250: LARGE_MINIMUM, LARGE_MAXIMUM);
251: return (-1);
252: }
253:
1.1 djm 254: /*
1.2 djm 255: * Set power to the length in bits of the prime to be generated.
256: * This is changed to 1 less than the desired safe prime moduli p.
257: */
1.1 djm 258: if (power > TEST_MAXIMUM) {
259: error("Too many bits: %u > %lu", power, TEST_MAXIMUM);
260: return (-1);
261: } else if (power < TEST_MINIMUM) {
262: error("Too few bits: %u < %u", power, TEST_MINIMUM);
263: return (-1);
264: }
265: power--; /* decrement before squaring */
266:
267: /*
1.2 djm 268: * The density of ordinary primes is on the order of 1/bits, so the
269: * density of safe primes should be about (1/bits)**2. Set test range
270: * to something well above bits**2 to be reasonably sure (but not
271: * guaranteed) of catching at least one safe prime.
1.1 djm 272: */
273: largewords = ((power * power) >> (SHIFT_WORD - TEST_POWER));
274:
275: /*
1.2 djm 276: * Need idea of how much memory is available. We don't have to use all
277: * of it.
1.1 djm 278: */
279: if (largememory > LARGE_MAXIMUM) {
280: logit("Limited memory: %u MB; limit %lu MB",
281: largememory, LARGE_MAXIMUM);
282: largememory = LARGE_MAXIMUM;
283: }
284:
285: if (largewords <= (largememory << SHIFT_MEGAWORD)) {
286: logit("Increased memory: %u MB; need %u bytes",
287: largememory, (largewords << SHIFT_BYTE));
288: largewords = (largememory << SHIFT_MEGAWORD);
289: } else if (largememory > 0) {
290: logit("Decreased memory: %u MB; want %u bytes",
291: largememory, (largewords << SHIFT_BYTE));
292: largewords = (largememory << SHIFT_MEGAWORD);
293: }
294:
1.13 djm 295: TinySieve = xcalloc(tinywords, sizeof(u_int32_t));
1.1 djm 296: tinybits = tinywords << SHIFT_WORD;
297:
1.13 djm 298: SmallSieve = xcalloc(smallwords, sizeof(u_int32_t));
1.1 djm 299: smallbits = smallwords << SHIFT_WORD;
300:
301: /*
302: * dynamically determine available memory
303: */
304: while ((LargeSieve = calloc(largewords, sizeof(u_int32_t))) == NULL)
305: largewords -= (1L << (SHIFT_MEGAWORD - 2)); /* 1/4 MB chunks */
306:
307: largebits = largewords << SHIFT_WORD;
308: largenumbers = largebits * 2; /* even numbers excluded */
309:
310: /* validation check: count the number of primes tried */
311: largetries = 0;
1.19 markus 312: if ((q = BN_new()) == NULL)
313: fatal("BN_new failed");
1.1 djm 314:
315: /*
1.2 djm 316: * Generate random starting point for subprime search, or use
317: * specified parameter.
1.1 djm 318: */
1.19 markus 319: if ((largebase = BN_new()) == NULL)
320: fatal("BN_new failed");
321: if (start == NULL) {
322: if (BN_rand(largebase, power, 1, 1) == 0)
323: fatal("BN_rand failed");
324: } else {
325: if (BN_copy(largebase, start) == NULL)
326: fatal("BN_copy: failed");
327: }
1.1 djm 328:
329: /* ensure odd */
1.19 markus 330: if (BN_set_bit(largebase, 0) == 0)
331: fatal("BN_set_bit: failed");
1.1 djm 332:
333: time(&time_start);
334:
1.2 djm 335: logit("%.24s Sieve next %u plus %u-bit", ctime(&time_start),
1.1 djm 336: largenumbers, power);
337: debug2("start point: 0x%s", BN_bn2hex(largebase));
338:
339: /*
1.2 djm 340: * TinySieve
341: */
1.1 djm 342: for (i = 0; i < tinybits; i++) {
343: if (BIT_TEST(TinySieve, i))
344: continue; /* 2*i+3 is composite */
345:
346: /* The next tiny prime */
347: t = 2 * i + 3;
348:
349: /* Mark all multiples of t */
350: for (j = i + t; j < tinybits; j += t)
351: BIT_SET(TinySieve, j);
352:
353: sieve_large(t);
354: }
355:
356: /*
1.2 djm 357: * Start the small block search at the next possible prime. To avoid
358: * fencepost errors, the last pass is skipped.
359: */
1.1 djm 360: for (smallbase = TINY_NUMBER + 3;
1.12 djm 361: smallbase < (SMALL_MAXIMUM - TINY_NUMBER);
362: smallbase += TINY_NUMBER) {
1.1 djm 363: for (i = 0; i < tinybits; i++) {
364: if (BIT_TEST(TinySieve, i))
365: continue; /* 2*i+3 is composite */
366:
367: /* The next tiny prime */
368: t = 2 * i + 3;
369: r = smallbase % t;
370:
371: if (r == 0) {
372: s = 0; /* t divides into smallbase exactly */
373: } else {
374: /* smallbase+s is first entry divisible by t */
375: s = t - r;
376: }
377:
378: /*
379: * The sieve omits even numbers, so ensure that
380: * smallbase+s is odd. Then, step through the sieve
381: * in increments of 2*t
382: */
383: if (s & 1)
384: s += t; /* Make smallbase+s odd, and s even */
385:
386: /* Mark all multiples of 2*t */
387: for (s /= 2; s < smallbits; s += t)
388: BIT_SET(SmallSieve, s);
389: }
390:
391: /*
1.2 djm 392: * SmallSieve
393: */
1.1 djm 394: for (i = 0; i < smallbits; i++) {
395: if (BIT_TEST(SmallSieve, i))
396: continue; /* 2*i+smallbase is composite */
397:
398: /* The next small prime */
399: sieve_large((2 * i) + smallbase);
400: }
401:
402: memset(SmallSieve, 0, smallwords << SHIFT_BYTE);
403: }
404:
405: time(&time_stop);
406:
407: logit("%.24s Sieved with %u small primes in %ld seconds",
408: ctime(&time_stop), largetries, (long) (time_stop - time_start));
409:
410: for (j = r = 0; j < largebits; j++) {
411: if (BIT_TEST(LargeSieve, j))
412: continue; /* Definitely composite, skip */
413:
414: debug2("test q = largebase+%u", 2 * j);
1.19 markus 415: if (BN_set_word(q, 2 * j) == 0)
416: fatal("BN_set_word failed");
417: if (BN_add(q, q, largebase) == 0)
418: fatal("BN_add failed");
1.21 djm 419: if (qfileout(out, MODULI_TYPE_SOPHIE_GERMAIN,
420: MODULI_TESTS_SIEVE, largetries,
421: (power - 1) /* MSB */, (0), q) == -1) {
1.1 djm 422: ret = -1;
423: break;
424: }
425:
426: r++; /* count q */
427: }
428:
429: time(&time_stop);
430:
431: xfree(LargeSieve);
432: xfree(SmallSieve);
433: xfree(TinySieve);
434:
435: logit("%.24s Found %u candidates", ctime(&time_stop), r);
436:
437: return (ret);
438: }
439:
1.23 dtucker 440: static void
441: write_checkpoint(char *cpfile, u_int32_t lineno)
442: {
443: FILE *fp;
444: char tmpfile[MAXPATHLEN];
445: int r;
446:
447: r = snprintf(tmpfile, sizeof(tmpfile), "%s.XXXXXXXXXX", cpfile);
448: if (r == -1 || r >= MAXPATHLEN) {
449: logit("write_checkpoint: temp pathname too long");
450: return;
451: }
452: if ((r = mkstemp(tmpfile)) == -1) {
453: logit("mkstemp(%s): %s", tmpfile, strerror(errno));
454: return;
455: }
456: if ((fp = fdopen(r, "w")) == NULL) {
457: logit("write_checkpoint: fdopen: %s", strerror(errno));
458: close(r);
459: return;
460: }
461: if (fprintf(fp, "%lu\n", (unsigned long)lineno) > 0 && fclose(fp) == 0
462: && rename(tmpfile, cpfile) == 0)
463: debug3("wrote checkpoint line %lu to '%s'",
464: (unsigned long)lineno, cpfile);
465: else
466: logit("failed to write to checkpoint file '%s': %s", cpfile,
467: strerror(errno));
468: }
469:
470: static unsigned long
471: read_checkpoint(char *cpfile)
472: {
473: FILE *fp;
474: unsigned long lineno = 0;
475:
476: if ((fp = fopen(cpfile, "r")) == NULL)
477: return 0;
478: if (fscanf(fp, "%lu\n", &lineno) < 1)
479: logit("Failed to load checkpoint from '%s'", cpfile);
480: else
481: logit("Loaded checkpoint from '%s' line %lu", cpfile, lineno);
482: fclose(fp);
483: return lineno;
484: }
485:
1.1 djm 486: /*
487: * perform a Miller-Rabin primality test
488: * on the list of candidates
489: * (checking both q and p)
490: * The result is a list of so-call "safe" primes
491: */
492: int
1.23 dtucker 493: prime_test(FILE *in, FILE *out, u_int32_t trials, u_int32_t generator_wanted,
494: char *checkpoint_file)
1.1 djm 495: {
496: BIGNUM *q, *p, *a;
497: BN_CTX *ctx;
498: char *cp, *lp;
499: u_int32_t count_in = 0, count_out = 0, count_possible = 0;
500: u_int32_t generator_known, in_tests, in_tries, in_type, in_size;
1.23 dtucker 501: unsigned long last_processed = 0;
1.1 djm 502: time_t time_start, time_stop;
503: int res;
1.7 djm 504:
505: if (trials < TRIAL_MINIMUM) {
506: error("Minimum primality trials is %d", TRIAL_MINIMUM);
507: return (-1);
508: }
1.1 djm 509:
510: time(&time_start);
511:
1.19 markus 512: if ((p = BN_new()) == NULL)
513: fatal("BN_new failed");
514: if ((q = BN_new()) == NULL)
515: fatal("BN_new failed");
516: if ((ctx = BN_CTX_new()) == NULL)
517: fatal("BN_CTX_new failed");
1.1 djm 518:
519: debug2("%.24s Final %u Miller-Rabin trials (%x generator)",
520: ctime(&time_start), trials, generator_wanted);
521:
1.23 dtucker 522: if (checkpoint_file != NULL)
523: last_processed = read_checkpoint(checkpoint_file);
524:
1.1 djm 525: res = 0;
526: lp = xmalloc(QLINESIZE + 1);
1.20 ray 527: while (fgets(lp, QLINESIZE + 1, in) != NULL) {
1.1 djm 528: count_in++;
1.23 dtucker 529: if (checkpoint_file != NULL) {
530: if (count_in <= last_processed) {
531: debug3("skipping line %u, before checkpoint",
532: count_in);
533: continue;
534: }
535: write_checkpoint(checkpoint_file, count_in);
536: }
1.20 ray 537: if (strlen(lp) < 14 || *lp == '!' || *lp == '#') {
1.1 djm 538: debug2("%10u: comment or short line", count_in);
539: continue;
540: }
541:
542: /* XXX - fragile parser */
543: /* time */
544: cp = &lp[14]; /* (skip) */
545:
546: /* type */
547: in_type = strtoul(cp, &cp, 10);
548:
549: /* tests */
550: in_tests = strtoul(cp, &cp, 10);
551:
1.21 djm 552: if (in_tests & MODULI_TESTS_COMPOSITE) {
1.1 djm 553: debug2("%10u: known composite", count_in);
554: continue;
555: }
1.5 djm 556:
1.1 djm 557: /* tries */
558: in_tries = strtoul(cp, &cp, 10);
559:
560: /* size (most significant bit) */
561: in_size = strtoul(cp, &cp, 10);
562:
563: /* generator (hex) */
564: generator_known = strtoul(cp, &cp, 16);
565:
566: /* Skip white space */
567: cp += strspn(cp, " ");
568:
569: /* modulus (hex) */
570: switch (in_type) {
1.21 djm 571: case MODULI_TYPE_SOPHIE_GERMAIN:
1.6 djm 572: debug2("%10u: (%u) Sophie-Germain", count_in, in_type);
1.1 djm 573: a = q;
1.19 markus 574: if (BN_hex2bn(&a, cp) == 0)
575: fatal("BN_hex2bn failed");
1.1 djm 576: /* p = 2*q + 1 */
1.19 markus 577: if (BN_lshift(p, q, 1) == 0)
578: fatal("BN_lshift failed");
579: if (BN_add_word(p, 1) == 0)
580: fatal("BN_add_word failed");
1.1 djm 581: in_size += 1;
582: generator_known = 0;
583: break;
1.21 djm 584: case MODULI_TYPE_UNSTRUCTURED:
585: case MODULI_TYPE_SAFE:
586: case MODULI_TYPE_SCHNORR:
587: case MODULI_TYPE_STRONG:
588: case MODULI_TYPE_UNKNOWN:
1.1 djm 589: debug2("%10u: (%u)", count_in, in_type);
590: a = p;
1.19 markus 591: if (BN_hex2bn(&a, cp) == 0)
592: fatal("BN_hex2bn failed");
1.1 djm 593: /* q = (p-1) / 2 */
1.19 markus 594: if (BN_rshift(q, p, 1) == 0)
595: fatal("BN_rshift failed");
1.1 djm 596: break;
1.5 djm 597: default:
598: debug2("Unknown prime type");
599: break;
1.1 djm 600: }
601:
602: /*
603: * due to earlier inconsistencies in interpretation, check
604: * the proposed bit size.
605: */
1.11 avsm 606: if ((u_int32_t)BN_num_bits(p) != (in_size + 1)) {
1.1 djm 607: debug2("%10u: bit size %u mismatch", count_in, in_size);
608: continue;
609: }
610: if (in_size < QSIZE_MINIMUM) {
611: debug2("%10u: bit size %u too short", count_in, in_size);
612: continue;
613: }
614:
1.21 djm 615: if (in_tests & MODULI_TESTS_MILLER_RABIN)
1.1 djm 616: in_tries += trials;
617: else
618: in_tries = trials;
1.5 djm 619:
1.1 djm 620: /*
621: * guess unknown generator
622: */
623: if (generator_known == 0) {
624: if (BN_mod_word(p, 24) == 11)
625: generator_known = 2;
626: else if (BN_mod_word(p, 12) == 5)
627: generator_known = 3;
628: else {
629: u_int32_t r = BN_mod_word(p, 10);
630:
1.5 djm 631: if (r == 3 || r == 7)
1.1 djm 632: generator_known = 5;
633: }
634: }
635: /*
636: * skip tests when desired generator doesn't match
637: */
638: if (generator_wanted > 0 &&
639: generator_wanted != generator_known) {
640: debug2("%10u: generator %d != %d",
641: count_in, generator_known, generator_wanted);
1.4 dtucker 642: continue;
643: }
644:
645: /*
646: * Primes with no known generator are useless for DH, so
647: * skip those.
648: */
649: if (generator_known == 0) {
650: debug2("%10u: no known generator", count_in);
1.1 djm 651: continue;
652: }
653:
654: count_possible++;
655:
656: /*
1.2 djm 657: * The (1/4)^N performance bound on Miller-Rabin is
658: * extremely pessimistic, so don't spend a lot of time
659: * really verifying that q is prime until after we know
660: * that p is also prime. A single pass will weed out the
1.1 djm 661: * vast majority of composite q's.
662: */
1.22 djm 663: if (BN_is_prime_ex(q, 1, ctx, NULL) <= 0) {
1.5 djm 664: debug("%10u: q failed first possible prime test",
1.1 djm 665: count_in);
666: continue;
667: }
1.2 djm 668:
1.1 djm 669: /*
1.2 djm 670: * q is possibly prime, so go ahead and really make sure
671: * that p is prime. If it is, then we can go back and do
672: * the same for q. If p is composite, chances are that
1.1 djm 673: * will show up on the first Rabin-Miller iteration so it
674: * doesn't hurt to specify a high iteration count.
675: */
1.22 djm 676: if (!BN_is_prime_ex(p, trials, ctx, NULL)) {
1.5 djm 677: debug("%10u: p is not prime", count_in);
1.1 djm 678: continue;
679: }
680: debug("%10u: p is almost certainly prime", count_in);
681:
682: /* recheck q more rigorously */
1.22 djm 683: if (!BN_is_prime_ex(q, trials - 1, ctx, NULL)) {
1.1 djm 684: debug("%10u: q is not prime", count_in);
685: continue;
686: }
687: debug("%10u: q is almost certainly prime", count_in);
688:
1.21 djm 689: if (qfileout(out, MODULI_TYPE_SAFE,
690: in_tests | MODULI_TESTS_MILLER_RABIN,
1.1 djm 691: in_tries, in_size, generator_known, p)) {
692: res = -1;
693: break;
694: }
695:
696: count_out++;
697: }
698:
699: time(&time_stop);
700: xfree(lp);
701: BN_free(p);
702: BN_free(q);
703: BN_CTX_free(ctx);
1.23 dtucker 704:
705: if (checkpoint_file != NULL)
706: unlink(checkpoint_file);
1.1 djm 707:
708: logit("%.24s Found %u safe primes of %u candidates in %ld seconds",
1.2 djm 709: ctime(&time_stop), count_out, count_possible,
1.1 djm 710: (long) (time_stop - time_start));
711:
712: return (res);
713: }
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