Annotation of src/usr.bin/ssh/moduli.c, Revision 1.26
1.26 ! dtucker 1: /* $OpenBSD: moduli.c,v 1.25 2011/10/19 00:06:10 djm 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 *);
1.26 ! dtucker 139: int prime_test(FILE *, FILE *, u_int32_t, u_int32_t, char *, unsigned long,
! 140: unsigned long);
1.1 djm 141:
142: /*
143: * print moduli out in consistent form,
144: */
145: static int
146: qfileout(FILE * ofile, u_int32_t otype, u_int32_t otests, u_int32_t otries,
147: u_int32_t osize, u_int32_t ogenerator, BIGNUM * omodulus)
148: {
149: struct tm *gtm;
150: time_t time_now;
151: int res;
152:
153: time(&time_now);
154: gtm = gmtime(&time_now);
1.2 djm 155:
1.1 djm 156: res = fprintf(ofile, "%04d%02d%02d%02d%02d%02d %u %u %u %u %x ",
157: gtm->tm_year + 1900, gtm->tm_mon + 1, gtm->tm_mday,
158: gtm->tm_hour, gtm->tm_min, gtm->tm_sec,
159: otype, otests, otries, osize, ogenerator);
160:
161: if (res < 0)
162: return (-1);
163:
164: if (BN_print_fp(ofile, omodulus) < 1)
165: return (-1);
166:
167: res = fprintf(ofile, "\n");
168: fflush(ofile);
169:
170: return (res > 0 ? 0 : -1);
171: }
172:
173:
174: /*
175: ** Sieve p's and q's with small factors
176: */
177: static void
178: sieve_large(u_int32_t s)
179: {
180: u_int32_t r, u;
181:
1.5 djm 182: debug3("sieve_large %u", s);
1.1 djm 183: largetries++;
184: /* r = largebase mod s */
185: r = BN_mod_word(largebase, s);
186: if (r == 0)
187: u = 0; /* s divides into largebase exactly */
188: else
189: u = s - r; /* largebase+u is first entry divisible by s */
190:
191: if (u < largebits * 2) {
192: /*
193: * The sieve omits p's and q's divisible by 2, so ensure that
194: * largebase+u is odd. Then, step through the sieve in
195: * increments of 2*s
196: */
197: if (u & 0x1)
198: u += s; /* Make largebase+u odd, and u even */
199:
200: /* Mark all multiples of 2*s */
201: for (u /= 2; u < largebits; u += s)
202: BIT_SET(LargeSieve, u);
203: }
204:
205: /* r = p mod s */
206: r = (2 * r + 1) % s;
207: if (r == 0)
208: u = 0; /* s divides p exactly */
209: else
210: u = s - r; /* p+u is first entry divisible by s */
211:
212: if (u < largebits * 4) {
213: /*
214: * The sieve omits p's divisible by 4, so ensure that
215: * largebase+u is not. Then, step through the sieve in
216: * increments of 4*s
217: */
218: while (u & 0x3) {
219: if (SMALL_MAXIMUM - u < s)
220: return;
221: u += s;
222: }
223:
224: /* Mark all multiples of 4*s */
225: for (u /= 4; u < largebits; u += s)
226: BIT_SET(LargeSieve, u);
227: }
228: }
229:
230: /*
1.6 djm 231: * list candidates for Sophie-Germain primes (where q = (p-1)/2)
1.1 djm 232: * to standard output.
233: * The list is checked against small known primes (less than 2**30).
234: */
235: int
1.11 avsm 236: gen_candidates(FILE *out, u_int32_t memory, u_int32_t power, BIGNUM *start)
1.1 djm 237: {
238: BIGNUM *q;
239: u_int32_t j, r, s, t;
240: u_int32_t smallwords = TINY_NUMBER >> 6;
241: u_int32_t tinywords = TINY_NUMBER >> 6;
242: time_t time_start, time_stop;
1.11 avsm 243: u_int32_t i;
244: int ret = 0;
1.1 djm 245:
246: largememory = memory;
247:
1.7 djm 248: if (memory != 0 &&
1.12 djm 249: (memory < LARGE_MINIMUM || memory > LARGE_MAXIMUM)) {
1.7 djm 250: error("Invalid memory amount (min %ld, max %ld)",
251: LARGE_MINIMUM, LARGE_MAXIMUM);
252: return (-1);
253: }
254:
1.1 djm 255: /*
1.2 djm 256: * Set power to the length in bits of the prime to be generated.
257: * This is changed to 1 less than the desired safe prime moduli p.
258: */
1.1 djm 259: if (power > TEST_MAXIMUM) {
260: error("Too many bits: %u > %lu", power, TEST_MAXIMUM);
261: return (-1);
262: } else if (power < TEST_MINIMUM) {
263: error("Too few bits: %u < %u", power, TEST_MINIMUM);
264: return (-1);
265: }
266: power--; /* decrement before squaring */
267:
268: /*
1.2 djm 269: * The density of ordinary primes is on the order of 1/bits, so the
270: * density of safe primes should be about (1/bits)**2. Set test range
271: * to something well above bits**2 to be reasonably sure (but not
272: * guaranteed) of catching at least one safe prime.
1.1 djm 273: */
274: largewords = ((power * power) >> (SHIFT_WORD - TEST_POWER));
275:
276: /*
1.2 djm 277: * Need idea of how much memory is available. We don't have to use all
278: * of it.
1.1 djm 279: */
280: if (largememory > LARGE_MAXIMUM) {
281: logit("Limited memory: %u MB; limit %lu MB",
282: largememory, LARGE_MAXIMUM);
283: largememory = LARGE_MAXIMUM;
284: }
285:
286: if (largewords <= (largememory << SHIFT_MEGAWORD)) {
287: logit("Increased memory: %u MB; need %u bytes",
288: largememory, (largewords << SHIFT_BYTE));
289: largewords = (largememory << SHIFT_MEGAWORD);
290: } else if (largememory > 0) {
291: logit("Decreased memory: %u MB; want %u bytes",
292: largememory, (largewords << SHIFT_BYTE));
293: largewords = (largememory << SHIFT_MEGAWORD);
294: }
295:
1.13 djm 296: TinySieve = xcalloc(tinywords, sizeof(u_int32_t));
1.1 djm 297: tinybits = tinywords << SHIFT_WORD;
298:
1.13 djm 299: SmallSieve = xcalloc(smallwords, sizeof(u_int32_t));
1.1 djm 300: smallbits = smallwords << SHIFT_WORD;
301:
302: /*
303: * dynamically determine available memory
304: */
305: while ((LargeSieve = calloc(largewords, sizeof(u_int32_t))) == NULL)
306: largewords -= (1L << (SHIFT_MEGAWORD - 2)); /* 1/4 MB chunks */
307:
308: largebits = largewords << SHIFT_WORD;
309: largenumbers = largebits * 2; /* even numbers excluded */
310:
311: /* validation check: count the number of primes tried */
312: largetries = 0;
1.19 markus 313: if ((q = BN_new()) == NULL)
314: fatal("BN_new failed");
1.1 djm 315:
316: /*
1.2 djm 317: * Generate random starting point for subprime search, or use
318: * specified parameter.
1.1 djm 319: */
1.19 markus 320: if ((largebase = BN_new()) == NULL)
321: fatal("BN_new failed");
322: if (start == NULL) {
323: if (BN_rand(largebase, power, 1, 1) == 0)
324: fatal("BN_rand failed");
325: } else {
326: if (BN_copy(largebase, start) == NULL)
327: fatal("BN_copy: failed");
328: }
1.1 djm 329:
330: /* ensure odd */
1.19 markus 331: if (BN_set_bit(largebase, 0) == 0)
332: fatal("BN_set_bit: failed");
1.1 djm 333:
334: time(&time_start);
335:
1.2 djm 336: logit("%.24s Sieve next %u plus %u-bit", ctime(&time_start),
1.1 djm 337: largenumbers, power);
338: debug2("start point: 0x%s", BN_bn2hex(largebase));
339:
340: /*
1.2 djm 341: * TinySieve
342: */
1.1 djm 343: for (i = 0; i < tinybits; i++) {
344: if (BIT_TEST(TinySieve, i))
345: continue; /* 2*i+3 is composite */
346:
347: /* The next tiny prime */
348: t = 2 * i + 3;
349:
350: /* Mark all multiples of t */
351: for (j = i + t; j < tinybits; j += t)
352: BIT_SET(TinySieve, j);
353:
354: sieve_large(t);
355: }
356:
357: /*
1.2 djm 358: * Start the small block search at the next possible prime. To avoid
359: * fencepost errors, the last pass is skipped.
360: */
1.1 djm 361: for (smallbase = TINY_NUMBER + 3;
1.12 djm 362: smallbase < (SMALL_MAXIMUM - TINY_NUMBER);
363: smallbase += TINY_NUMBER) {
1.1 djm 364: for (i = 0; i < tinybits; i++) {
365: if (BIT_TEST(TinySieve, i))
366: continue; /* 2*i+3 is composite */
367:
368: /* The next tiny prime */
369: t = 2 * i + 3;
370: r = smallbase % t;
371:
372: if (r == 0) {
373: s = 0; /* t divides into smallbase exactly */
374: } else {
375: /* smallbase+s is first entry divisible by t */
376: s = t - r;
377: }
378:
379: /*
380: * The sieve omits even numbers, so ensure that
381: * smallbase+s is odd. Then, step through the sieve
382: * in increments of 2*t
383: */
384: if (s & 1)
385: s += t; /* Make smallbase+s odd, and s even */
386:
387: /* Mark all multiples of 2*t */
388: for (s /= 2; s < smallbits; s += t)
389: BIT_SET(SmallSieve, s);
390: }
391:
392: /*
1.2 djm 393: * SmallSieve
394: */
1.1 djm 395: for (i = 0; i < smallbits; i++) {
396: if (BIT_TEST(SmallSieve, i))
397: continue; /* 2*i+smallbase is composite */
398:
399: /* The next small prime */
400: sieve_large((2 * i) + smallbase);
401: }
402:
403: memset(SmallSieve, 0, smallwords << SHIFT_BYTE);
404: }
405:
406: time(&time_stop);
407:
408: logit("%.24s Sieved with %u small primes in %ld seconds",
409: ctime(&time_stop), largetries, (long) (time_stop - time_start));
410:
411: for (j = r = 0; j < largebits; j++) {
412: if (BIT_TEST(LargeSieve, j))
413: continue; /* Definitely composite, skip */
414:
415: debug2("test q = largebase+%u", 2 * j);
1.19 markus 416: if (BN_set_word(q, 2 * j) == 0)
417: fatal("BN_set_word failed");
418: if (BN_add(q, q, largebase) == 0)
419: fatal("BN_add failed");
1.21 djm 420: if (qfileout(out, MODULI_TYPE_SOPHIE_GERMAIN,
421: MODULI_TESTS_SIEVE, largetries,
422: (power - 1) /* MSB */, (0), q) == -1) {
1.1 djm 423: ret = -1;
424: break;
425: }
426:
427: r++; /* count q */
428: }
429:
430: time(&time_stop);
431:
432: xfree(LargeSieve);
433: xfree(SmallSieve);
434: xfree(TinySieve);
435:
436: logit("%.24s Found %u candidates", ctime(&time_stop), r);
437:
438: return (ret);
439: }
440:
1.23 dtucker 441: static void
442: write_checkpoint(char *cpfile, u_int32_t lineno)
443: {
444: FILE *fp;
1.25 djm 445: char tmp[MAXPATHLEN];
1.23 dtucker 446: int r;
447:
1.25 djm 448: r = snprintf(tmp, sizeof(tmp), "%s.XXXXXXXXXX", cpfile);
1.23 dtucker 449: if (r == -1 || r >= MAXPATHLEN) {
450: logit("write_checkpoint: temp pathname too long");
451: return;
452: }
1.25 djm 453: if ((r = mkstemp(tmp)) == -1) {
454: logit("mkstemp(%s): %s", tmp, strerror(errno));
1.23 dtucker 455: return;
456: }
457: if ((fp = fdopen(r, "w")) == NULL) {
458: logit("write_checkpoint: fdopen: %s", strerror(errno));
459: close(r);
460: return;
461: }
462: if (fprintf(fp, "%lu\n", (unsigned long)lineno) > 0 && fclose(fp) == 0
1.25 djm 463: && rename(tmp, cpfile) == 0)
1.23 dtucker 464: debug3("wrote checkpoint line %lu to '%s'",
465: (unsigned long)lineno, cpfile);
466: else
467: logit("failed to write to checkpoint file '%s': %s", cpfile,
468: strerror(errno));
469: }
470:
471: static unsigned long
472: read_checkpoint(char *cpfile)
473: {
474: FILE *fp;
475: unsigned long lineno = 0;
476:
477: if ((fp = fopen(cpfile, "r")) == NULL)
478: return 0;
479: if (fscanf(fp, "%lu\n", &lineno) < 1)
480: logit("Failed to load checkpoint from '%s'", cpfile);
481: else
482: logit("Loaded checkpoint from '%s' line %lu", cpfile, lineno);
483: fclose(fp);
484: return lineno;
485: }
486:
1.1 djm 487: /*
488: * perform a Miller-Rabin primality test
489: * on the list of candidates
490: * (checking both q and p)
491: * The result is a list of so-call "safe" primes
492: */
493: int
1.23 dtucker 494: prime_test(FILE *in, FILE *out, u_int32_t trials, u_int32_t generator_wanted,
1.26 ! dtucker 495: char *checkpoint_file, unsigned long start_lineno, unsigned long num_lines)
1.1 djm 496: {
497: BIGNUM *q, *p, *a;
498: BN_CTX *ctx;
499: char *cp, *lp;
500: u_int32_t count_in = 0, count_out = 0, count_possible = 0;
501: u_int32_t generator_known, in_tests, in_tries, in_type, in_size;
1.26 ! dtucker 502: unsigned long last_processed = 0, end_lineno;
1.1 djm 503: time_t time_start, time_stop;
504: int res;
1.7 djm 505:
506: if (trials < TRIAL_MINIMUM) {
507: error("Minimum primality trials is %d", TRIAL_MINIMUM);
508: return (-1);
509: }
1.1 djm 510:
511: time(&time_start);
512:
1.19 markus 513: if ((p = BN_new()) == NULL)
514: fatal("BN_new failed");
515: if ((q = BN_new()) == NULL)
516: fatal("BN_new failed");
517: if ((ctx = BN_CTX_new()) == NULL)
518: fatal("BN_CTX_new failed");
1.1 djm 519:
520: debug2("%.24s Final %u Miller-Rabin trials (%x generator)",
521: ctime(&time_start), trials, generator_wanted);
522:
1.23 dtucker 523: if (checkpoint_file != NULL)
524: last_processed = read_checkpoint(checkpoint_file);
1.26 ! dtucker 525: if (start_lineno > last_processed)
! 526: last_processed = start_lineno;
! 527: if (num_lines == 0)
! 528: end_lineno = ULONG_MAX;
! 529: else
! 530: end_lineno = last_processed + num_lines;
! 531: debug2("process line %lu to line %lu", last_processed, end_lineno);
1.23 dtucker 532:
1.1 djm 533: res = 0;
534: lp = xmalloc(QLINESIZE + 1);
1.26 ! dtucker 535: while (fgets(lp, QLINESIZE + 1, in) != NULL && count_in < end_lineno) {
1.1 djm 536: count_in++;
1.23 dtucker 537: if (checkpoint_file != NULL) {
538: if (count_in <= last_processed) {
539: debug3("skipping line %u, before checkpoint",
540: count_in);
541: continue;
542: }
543: write_checkpoint(checkpoint_file, count_in);
544: }
1.20 ray 545: if (strlen(lp) < 14 || *lp == '!' || *lp == '#') {
1.1 djm 546: debug2("%10u: comment or short line", count_in);
547: continue;
548: }
549:
550: /* XXX - fragile parser */
551: /* time */
552: cp = &lp[14]; /* (skip) */
553:
554: /* type */
555: in_type = strtoul(cp, &cp, 10);
556:
557: /* tests */
558: in_tests = strtoul(cp, &cp, 10);
559:
1.21 djm 560: if (in_tests & MODULI_TESTS_COMPOSITE) {
1.1 djm 561: debug2("%10u: known composite", count_in);
562: continue;
563: }
1.5 djm 564:
1.1 djm 565: /* tries */
566: in_tries = strtoul(cp, &cp, 10);
567:
568: /* size (most significant bit) */
569: in_size = strtoul(cp, &cp, 10);
570:
571: /* generator (hex) */
572: generator_known = strtoul(cp, &cp, 16);
573:
574: /* Skip white space */
575: cp += strspn(cp, " ");
576:
577: /* modulus (hex) */
578: switch (in_type) {
1.21 djm 579: case MODULI_TYPE_SOPHIE_GERMAIN:
1.6 djm 580: debug2("%10u: (%u) Sophie-Germain", count_in, in_type);
1.1 djm 581: a = q;
1.19 markus 582: if (BN_hex2bn(&a, cp) == 0)
583: fatal("BN_hex2bn failed");
1.1 djm 584: /* p = 2*q + 1 */
1.19 markus 585: if (BN_lshift(p, q, 1) == 0)
586: fatal("BN_lshift failed");
587: if (BN_add_word(p, 1) == 0)
588: fatal("BN_add_word failed");
1.1 djm 589: in_size += 1;
590: generator_known = 0;
591: break;
1.21 djm 592: case MODULI_TYPE_UNSTRUCTURED:
593: case MODULI_TYPE_SAFE:
594: case MODULI_TYPE_SCHNORR:
595: case MODULI_TYPE_STRONG:
596: case MODULI_TYPE_UNKNOWN:
1.1 djm 597: debug2("%10u: (%u)", count_in, in_type);
598: a = p;
1.19 markus 599: if (BN_hex2bn(&a, cp) == 0)
600: fatal("BN_hex2bn failed");
1.1 djm 601: /* q = (p-1) / 2 */
1.19 markus 602: if (BN_rshift(q, p, 1) == 0)
603: fatal("BN_rshift failed");
1.1 djm 604: break;
1.5 djm 605: default:
606: debug2("Unknown prime type");
607: break;
1.1 djm 608: }
609:
610: /*
611: * due to earlier inconsistencies in interpretation, check
612: * the proposed bit size.
613: */
1.11 avsm 614: if ((u_int32_t)BN_num_bits(p) != (in_size + 1)) {
1.1 djm 615: debug2("%10u: bit size %u mismatch", count_in, in_size);
616: continue;
617: }
618: if (in_size < QSIZE_MINIMUM) {
619: debug2("%10u: bit size %u too short", count_in, in_size);
620: continue;
621: }
622:
1.21 djm 623: if (in_tests & MODULI_TESTS_MILLER_RABIN)
1.1 djm 624: in_tries += trials;
625: else
626: in_tries = trials;
1.5 djm 627:
1.1 djm 628: /*
629: * guess unknown generator
630: */
631: if (generator_known == 0) {
632: if (BN_mod_word(p, 24) == 11)
633: generator_known = 2;
634: else if (BN_mod_word(p, 12) == 5)
635: generator_known = 3;
636: else {
637: u_int32_t r = BN_mod_word(p, 10);
638:
1.5 djm 639: if (r == 3 || r == 7)
1.1 djm 640: generator_known = 5;
641: }
642: }
643: /*
644: * skip tests when desired generator doesn't match
645: */
646: if (generator_wanted > 0 &&
647: generator_wanted != generator_known) {
648: debug2("%10u: generator %d != %d",
649: count_in, generator_known, generator_wanted);
1.4 dtucker 650: continue;
651: }
652:
653: /*
654: * Primes with no known generator are useless for DH, so
655: * skip those.
656: */
657: if (generator_known == 0) {
658: debug2("%10u: no known generator", count_in);
1.1 djm 659: continue;
660: }
661:
662: count_possible++;
663:
664: /*
1.2 djm 665: * The (1/4)^N performance bound on Miller-Rabin is
666: * extremely pessimistic, so don't spend a lot of time
667: * really verifying that q is prime until after we know
668: * that p is also prime. A single pass will weed out the
1.1 djm 669: * vast majority of composite q's.
670: */
1.22 djm 671: if (BN_is_prime_ex(q, 1, ctx, NULL) <= 0) {
1.5 djm 672: debug("%10u: q failed first possible prime test",
1.1 djm 673: count_in);
674: continue;
675: }
1.2 djm 676:
1.1 djm 677: /*
1.2 djm 678: * q is possibly prime, so go ahead and really make sure
679: * that p is prime. If it is, then we can go back and do
680: * the same for q. If p is composite, chances are that
1.1 djm 681: * will show up on the first Rabin-Miller iteration so it
682: * doesn't hurt to specify a high iteration count.
683: */
1.22 djm 684: if (!BN_is_prime_ex(p, trials, ctx, NULL)) {
1.5 djm 685: debug("%10u: p is not prime", count_in);
1.1 djm 686: continue;
687: }
688: debug("%10u: p is almost certainly prime", count_in);
689:
690: /* recheck q more rigorously */
1.22 djm 691: if (!BN_is_prime_ex(q, trials - 1, ctx, NULL)) {
1.1 djm 692: debug("%10u: q is not prime", count_in);
693: continue;
694: }
695: debug("%10u: q is almost certainly prime", count_in);
696:
1.21 djm 697: if (qfileout(out, MODULI_TYPE_SAFE,
698: in_tests | MODULI_TESTS_MILLER_RABIN,
1.1 djm 699: in_tries, in_size, generator_known, p)) {
700: res = -1;
701: break;
702: }
703:
704: count_out++;
705: }
706:
707: time(&time_stop);
708: xfree(lp);
709: BN_free(p);
710: BN_free(q);
711: BN_CTX_free(ctx);
1.23 dtucker 712:
713: if (checkpoint_file != NULL)
714: unlink(checkpoint_file);
1.1 djm 715:
716: logit("%.24s Found %u safe primes of %u candidates in %ld seconds",
1.2 djm 717: ctime(&time_stop), count_out, count_possible,
1.1 djm 718: (long) (time_stop - time_start));
719:
720: return (res);
721: }