1/* $OpenBSD: moduli.c,v 1.26 2012/07/06 00:41:59 dtucker 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#include <sys/param.h>
43#include <sys/types.h>
44
45#ifdef __APPLE_CRYPTO__
46#include "ossl-bn.h"
47#include "ossl-dh.h"
48#else
49#include <openssl/bn.h>
50#include <openssl/dh.h>
51#endif
52
53#include <errno.h>
54#include <stdio.h>
55#include <stdlib.h>
56#include <string.h>
57#include <stdarg.h>
58#include <time.h>
59#include <unistd.h>
60
61#include "xmalloc.h"
62#include "dh.h"
63#include "log.h"
64
65#include "openbsd-compat/openssl-compat.h"
66
67/*
68 * File output defines
69 */
70
71/* need line long enough for largest moduli plus headers */
72#define QLINESIZE		(100+8192)
73
74/*
75 * Size: decimal.
76 * Specifies the number of the most significant bit (0 to M).
77 * WARNING: internally, usually 1 to N.
78 */
79#define QSIZE_MINIMUM		(511)
80
81/*
82 * Prime sieving defines
83 */
84
85/* Constant: assuming 8 bit bytes and 32 bit words */
86#define SHIFT_BIT	(3)
87#define SHIFT_BYTE	(2)
88#define SHIFT_WORD	(SHIFT_BIT+SHIFT_BYTE)
89#define SHIFT_MEGABYTE	(20)
90#define SHIFT_MEGAWORD	(SHIFT_MEGABYTE-SHIFT_BYTE)
91
92/*
93 * Using virtual memory can cause thrashing.  This should be the largest
94 * number that is supported without a large amount of disk activity --
95 * that would increase the run time from hours to days or weeks!
96 */
97#define LARGE_MINIMUM	(8UL)	/* megabytes */
98
99/*
100 * Do not increase this number beyond the unsigned integer bit size.
101 * Due to a multiple of 4, it must be LESS than 128 (yielding 2**30 bits).
102 */
103#define LARGE_MAXIMUM	(127UL)	/* megabytes */
104
105/*
106 * Constant: when used with 32-bit integers, the largest sieve prime
107 * has to be less than 2**32.
108 */
109#define SMALL_MAXIMUM	(0xffffffffUL)
110
111/* Constant: can sieve all primes less than 2**32, as 65537**2 > 2**32-1. */
112#define TINY_NUMBER	(1UL<<16)
113
114/* Ensure enough bit space for testing 2*q. */
115#define TEST_MAXIMUM	(1UL<<16)
116#define TEST_MINIMUM	(QSIZE_MINIMUM + 1)
117/* real TEST_MINIMUM	(1UL << (SHIFT_WORD - TEST_POWER)) */
118#define TEST_POWER	(3)	/* 2**n, n < SHIFT_WORD */
119
120/* bit operations on 32-bit words */
121#define BIT_CLEAR(a,n)	((a)[(n)>>SHIFT_WORD] &= ~(1L << ((n) & 31)))
122#define BIT_SET(a,n)	((a)[(n)>>SHIFT_WORD] |= (1L << ((n) & 31)))
123#define BIT_TEST(a,n)	((a)[(n)>>SHIFT_WORD] & (1L << ((n) & 31)))
124
125/*
126 * Prime testing defines
127 */
128
129/* Minimum number of primality tests to perform */
130#define TRIAL_MINIMUM	(4)
131
132/*
133 * Sieving data (XXX - move to struct)
134 */
135
136/* sieve 2**16 */
137static u_int32_t *TinySieve, tinybits;
138
139/* sieve 2**30 in 2**16 parts */
140static u_int32_t *SmallSieve, smallbits, smallbase;
141
142/* sieve relative to the initial value */
143static u_int32_t *LargeSieve, largewords, largetries, largenumbers;
144static u_int32_t largebits, largememory;	/* megabytes */
145static BIGNUM *largebase;
146
147int gen_candidates(FILE *, u_int32_t, u_int32_t, BIGNUM *);
148int prime_test(FILE *, FILE *, u_int32_t, u_int32_t, char *, unsigned long,
149    unsigned long);
150
151/*
152 * print moduli out in consistent form,
153 */
154static int
155qfileout(FILE * ofile, u_int32_t otype, u_int32_t otests, u_int32_t otries,
156    u_int32_t osize, u_int32_t ogenerator, BIGNUM * omodulus)
157{
158	struct tm *gtm;
159	time_t time_now;
160	int res;
161
162	time(&time_now);
163	gtm = gmtime(&time_now);
164
165	res = fprintf(ofile, "%04d%02d%02d%02d%02d%02d %u %u %u %u %x ",
166	    gtm->tm_year + 1900, gtm->tm_mon + 1, gtm->tm_mday,
167	    gtm->tm_hour, gtm->tm_min, gtm->tm_sec,
168	    otype, otests, otries, osize, ogenerator);
169
170	if (res < 0)
171		return (-1);
172
173	if (BN_print_fp(ofile, omodulus) < 1)
174		return (-1);
175
176	res = fprintf(ofile, "\n");
177	fflush(ofile);
178
179	return (res > 0 ? 0 : -1);
180}
181
182
183/*
184 ** Sieve p's and q's with small factors
185 */
186static void
187sieve_large(u_int32_t s)
188{
189	u_int32_t r, u;
190
191	debug3("sieve_large %u", s);
192	largetries++;
193	/* r = largebase mod s */
194	r = BN_mod_word(largebase, s);
195	if (r == 0)
196		u = 0; /* s divides into largebase exactly */
197	else
198		u = s - r; /* largebase+u is first entry divisible by s */
199
200	if (u < largebits * 2) {
201		/*
202		 * The sieve omits p's and q's divisible by 2, so ensure that
203		 * largebase+u is odd. Then, step through the sieve in
204		 * increments of 2*s
205		 */
206		if (u & 0x1)
207			u += s; /* Make largebase+u odd, and u even */
208
209		/* Mark all multiples of 2*s */
210		for (u /= 2; u < largebits; u += s)
211			BIT_SET(LargeSieve, u);
212	}
213
214	/* r = p mod s */
215	r = (2 * r + 1) % s;
216	if (r == 0)
217		u = 0; /* s divides p exactly */
218	else
219		u = s - r; /* p+u is first entry divisible by s */
220
221	if (u < largebits * 4) {
222		/*
223		 * The sieve omits p's divisible by 4, so ensure that
224		 * largebase+u is not. Then, step through the sieve in
225		 * increments of 4*s
226		 */
227		while (u & 0x3) {
228			if (SMALL_MAXIMUM - u < s)
229				return;
230			u += s;
231		}
232
233		/* Mark all multiples of 4*s */
234		for (u /= 4; u < largebits; u += s)
235			BIT_SET(LargeSieve, u);
236	}
237}
238
239/*
240 * list candidates for Sophie-Germain primes (where q = (p-1)/2)
241 * to standard output.
242 * The list is checked against small known primes (less than 2**30).
243 */
244int
245gen_candidates(FILE *out, u_int32_t memory, u_int32_t power, BIGNUM *start)
246{
247	BIGNUM *q;
248	u_int32_t j, r, s, t;
249	u_int32_t smallwords = TINY_NUMBER >> 6;
250	u_int32_t tinywords = TINY_NUMBER >> 6;
251	time_t time_start, time_stop;
252	u_int32_t i;
253	int ret = 0;
254
255	largememory = memory;
256
257	if (memory != 0 &&
258	    (memory < LARGE_MINIMUM || memory > LARGE_MAXIMUM)) {
259		error("Invalid memory amount (min %ld, max %ld)",
260		    LARGE_MINIMUM, LARGE_MAXIMUM);
261		return (-1);
262	}
263
264	/*
265	 * Set power to the length in bits of the prime to be generated.
266	 * This is changed to 1 less than the desired safe prime moduli p.
267	 */
268	if (power > TEST_MAXIMUM) {
269		error("Too many bits: %u > %lu", power, TEST_MAXIMUM);
270		return (-1);
271	} else if (power < TEST_MINIMUM) {
272		error("Too few bits: %u < %u", power, TEST_MINIMUM);
273		return (-1);
274	}
275	power--; /* decrement before squaring */
276
277	/*
278	 * The density of ordinary primes is on the order of 1/bits, so the
279	 * density of safe primes should be about (1/bits)**2. Set test range
280	 * to something well above bits**2 to be reasonably sure (but not
281	 * guaranteed) of catching at least one safe prime.
282	 */
283	largewords = ((power * power) >> (SHIFT_WORD - TEST_POWER));
284
285	/*
286	 * Need idea of how much memory is available. We don't have to use all
287	 * of it.
288	 */
289	if (largememory > LARGE_MAXIMUM) {
290		logit("Limited memory: %u MB; limit %lu MB",
291		    largememory, LARGE_MAXIMUM);
292		largememory = LARGE_MAXIMUM;
293	}
294
295	if (largewords <= (largememory << SHIFT_MEGAWORD)) {
296		logit("Increased memory: %u MB; need %u bytes",
297		    largememory, (largewords << SHIFT_BYTE));
298		largewords = (largememory << SHIFT_MEGAWORD);
299	} else if (largememory > 0) {
300		logit("Decreased memory: %u MB; want %u bytes",
301		    largememory, (largewords << SHIFT_BYTE));
302		largewords = (largememory << SHIFT_MEGAWORD);
303	}
304
305	TinySieve = xcalloc(tinywords, sizeof(u_int32_t));
306	tinybits = tinywords << SHIFT_WORD;
307
308	SmallSieve = xcalloc(smallwords, sizeof(u_int32_t));
309	smallbits = smallwords << SHIFT_WORD;
310
311	/*
312	 * dynamically determine available memory
313	 */
314	while ((LargeSieve = calloc(largewords, sizeof(u_int32_t))) == NULL)
315		largewords -= (1L << (SHIFT_MEGAWORD - 2)); /* 1/4 MB chunks */
316
317	largebits = largewords << SHIFT_WORD;
318	largenumbers = largebits * 2;	/* even numbers excluded */
319
320	/* validation check: count the number of primes tried */
321	largetries = 0;
322	if ((q = BN_new()) == NULL)
323		fatal("BN_new failed");
324
325	/*
326	 * Generate random starting point for subprime search, or use
327	 * specified parameter.
328	 */
329	if ((largebase = BN_new()) == NULL)
330		fatal("BN_new failed");
331	if (start == NULL) {
332		if (BN_rand(largebase, power, 1, 1) == 0)
333			fatal("BN_rand failed");
334	} else {
335		if (BN_copy(largebase, start) == NULL)
336			fatal("BN_copy: failed");
337	}
338
339	/* ensure odd */
340	if (BN_set_bit(largebase, 0) == 0)
341		fatal("BN_set_bit: failed");
342
343	time(&time_start);
344
345	logit("%.24s Sieve next %u plus %u-bit", ctime(&time_start),
346	    largenumbers, power);
347	debug2("start point: 0x%s", BN_bn2hex(largebase));
348
349	/*
350	 * TinySieve
351	 */
352	for (i = 0; i < tinybits; i++) {
353		if (BIT_TEST(TinySieve, i))
354			continue; /* 2*i+3 is composite */
355
356		/* The next tiny prime */
357		t = 2 * i + 3;
358
359		/* Mark all multiples of t */
360		for (j = i + t; j < tinybits; j += t)
361			BIT_SET(TinySieve, j);
362
363		sieve_large(t);
364	}
365
366	/*
367	 * Start the small block search at the next possible prime. To avoid
368	 * fencepost errors, the last pass is skipped.
369	 */
370	for (smallbase = TINY_NUMBER + 3;
371	    smallbase < (SMALL_MAXIMUM - TINY_NUMBER);
372	    smallbase += TINY_NUMBER) {
373		for (i = 0; i < tinybits; i++) {
374			if (BIT_TEST(TinySieve, i))
375				continue; /* 2*i+3 is composite */
376
377			/* The next tiny prime */
378			t = 2 * i + 3;
379			r = smallbase % t;
380
381			if (r == 0) {
382				s = 0; /* t divides into smallbase exactly */
383			} else {
384				/* smallbase+s is first entry divisible by t */
385				s = t - r;
386			}
387
388			/*
389			 * The sieve omits even numbers, so ensure that
390			 * smallbase+s is odd. Then, step through the sieve
391			 * in increments of 2*t
392			 */
393			if (s & 1)
394				s += t; /* Make smallbase+s odd, and s even */
395
396			/* Mark all multiples of 2*t */
397			for (s /= 2; s < smallbits; s += t)
398				BIT_SET(SmallSieve, s);
399		}
400
401		/*
402		 * SmallSieve
403		 */
404		for (i = 0; i < smallbits; i++) {
405			if (BIT_TEST(SmallSieve, i))
406				continue; /* 2*i+smallbase is composite */
407
408			/* The next small prime */
409			sieve_large((2 * i) + smallbase);
410		}
411
412		memset(SmallSieve, 0, smallwords << SHIFT_BYTE);
413	}
414
415	time(&time_stop);
416
417	logit("%.24s Sieved with %u small primes in %ld seconds",
418	    ctime(&time_stop), largetries, (long) (time_stop - time_start));
419
420	for (j = r = 0; j < largebits; j++) {
421		if (BIT_TEST(LargeSieve, j))
422			continue; /* Definitely composite, skip */
423
424		debug2("test q = largebase+%u", 2 * j);
425		if (BN_set_word(q, 2 * j) == 0)
426			fatal("BN_set_word failed");
427		if (BN_add(q, q, largebase) == 0)
428			fatal("BN_add failed");
429		if (qfileout(out, MODULI_TYPE_SOPHIE_GERMAIN,
430		    MODULI_TESTS_SIEVE, largetries,
431		    (power - 1) /* MSB */, (0), q) == -1) {
432			ret = -1;
433			break;
434		}
435
436		r++; /* count q */
437	}
438
439	time(&time_stop);
440
441	xfree(LargeSieve);
442	xfree(SmallSieve);
443	xfree(TinySieve);
444
445	logit("%.24s Found %u candidates", ctime(&time_stop), r);
446
447	return (ret);
448}
449
450static void
451write_checkpoint(char *cpfile, u_int32_t lineno)
452{
453	FILE *fp;
454	char tmp[MAXPATHLEN];
455	int r;
456
457	r = snprintf(tmp, sizeof(tmp), "%s.XXXXXXXXXX", cpfile);
458	if (r == -1 || r >= MAXPATHLEN) {
459		logit("write_checkpoint: temp pathname too long");
460		return;
461	}
462	if ((r = mkstemp(tmp)) == -1) {
463		logit("mkstemp(%s): %s", tmp, strerror(errno));
464		return;
465	}
466	if ((fp = fdopen(r, "w")) == NULL) {
467		logit("write_checkpoint: fdopen: %s", strerror(errno));
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
480static unsigned long
481read_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/*
497 * perform a Miller-Rabin primality test
498 * on the list of candidates
499 * (checking both q and p)
500 * The result is a list of so-call "safe" primes
501 */
502int
503prime_test(FILE *in, FILE *out, u_int32_t trials, u_int32_t generator_wanted,
504    char *checkpoint_file, unsigned long start_lineno, unsigned long num_lines)
505{
506	BIGNUM *q, *p, *a;
507	BN_CTX *ctx;
508	char *cp, *lp;
509	u_int32_t count_in = 0, count_out = 0, count_possible = 0;
510	u_int32_t generator_known, in_tests, in_tries, in_type, in_size;
511	unsigned long last_processed = 0, end_lineno;
512	time_t time_start, time_stop;
513	int res;
514
515	if (trials < TRIAL_MINIMUM) {
516		error("Minimum primality trials is %d", TRIAL_MINIMUM);
517		return (-1);
518	}
519
520	time(&time_start);
521
522	if ((p = BN_new()) == NULL)
523		fatal("BN_new failed");
524	if ((q = BN_new()) == NULL)
525		fatal("BN_new failed");
526	if ((ctx = BN_CTX_new()) == NULL)
527		fatal("BN_CTX_new failed");
528
529	debug2("%.24s Final %u Miller-Rabin trials (%x generator)",
530	    ctime(&time_start), trials, generator_wanted);
531
532	if (checkpoint_file != NULL)
533		last_processed = read_checkpoint(checkpoint_file);
534	if (start_lineno > last_processed)
535		last_processed = start_lineno;
536	if (num_lines == 0)
537		end_lineno = ULONG_MAX;
538	else
539		end_lineno = last_processed + num_lines;
540	debug2("process line %lu to line %lu", last_processed, end_lineno);
541
542	res = 0;
543	lp = xmalloc(QLINESIZE + 1);
544	while (fgets(lp, QLINESIZE + 1, in) != NULL && count_in < end_lineno) {
545		count_in++;
546		if (checkpoint_file != NULL) {
547			if (count_in <= last_processed) {
548				debug3("skipping line %u, before checkpoint",
549				    count_in);
550				continue;
551			}
552			write_checkpoint(checkpoint_file, count_in);
553		}
554		if (strlen(lp) < 14 || *lp == '!' || *lp == '#') {
555			debug2("%10u: comment or short line", count_in);
556			continue;
557		}
558
559		/* XXX - fragile parser */
560		/* time */
561		cp = &lp[14];	/* (skip) */
562
563		/* type */
564		in_type = strtoul(cp, &cp, 10);
565
566		/* tests */
567		in_tests = strtoul(cp, &cp, 10);
568
569		if (in_tests & MODULI_TESTS_COMPOSITE) {
570			debug2("%10u: known composite", count_in);
571			continue;
572		}
573
574		/* tries */
575		in_tries = strtoul(cp, &cp, 10);
576
577		/* size (most significant bit) */
578		in_size = strtoul(cp, &cp, 10);
579
580		/* generator (hex) */
581		generator_known = strtoul(cp, &cp, 16);
582
583		/* Skip white space */
584		cp += strspn(cp, " ");
585
586		/* modulus (hex) */
587		switch (in_type) {
588		case MODULI_TYPE_SOPHIE_GERMAIN:
589			debug2("%10u: (%u) Sophie-Germain", count_in, in_type);
590			a = q;
591			if (BN_hex2bn(&a, cp) == 0)
592				fatal("BN_hex2bn failed");
593			/* p = 2*q + 1 */
594			if (BN_lshift(p, q, 1) == 0)
595				fatal("BN_lshift failed");
596			if (BN_add_word(p, 1) == 0)
597				fatal("BN_add_word failed");
598			in_size += 1;
599			generator_known = 0;
600			break;
601		case MODULI_TYPE_UNSTRUCTURED:
602		case MODULI_TYPE_SAFE:
603		case MODULI_TYPE_SCHNORR:
604		case MODULI_TYPE_STRONG:
605		case MODULI_TYPE_UNKNOWN:
606			debug2("%10u: (%u)", count_in, in_type);
607			a = p;
608			if (BN_hex2bn(&a, cp) == 0)
609				fatal("BN_hex2bn failed");
610			/* q = (p-1) / 2 */
611			if (BN_rshift(q, p, 1) == 0)
612				fatal("BN_rshift failed");
613			break;
614		default:
615			debug2("Unknown prime type");
616			break;
617		}
618
619		/*
620		 * due to earlier inconsistencies in interpretation, check
621		 * the proposed bit size.
622		 */
623		if ((u_int32_t)BN_num_bits(p) != (in_size + 1)) {
624			debug2("%10u: bit size %u mismatch", count_in, in_size);
625			continue;
626		}
627		if (in_size < QSIZE_MINIMUM) {
628			debug2("%10u: bit size %u too short", count_in, in_size);
629			continue;
630		}
631
632		if (in_tests & MODULI_TESTS_MILLER_RABIN)
633			in_tries += trials;
634		else
635			in_tries = trials;
636
637		/*
638		 * guess unknown generator
639		 */
640		if (generator_known == 0) {
641			if (BN_mod_word(p, 24) == 11)
642				generator_known = 2;
643			else if (BN_mod_word(p, 12) == 5)
644				generator_known = 3;
645			else {
646				u_int32_t r = BN_mod_word(p, 10);
647
648				if (r == 3 || r == 7)
649					generator_known = 5;
650			}
651		}
652		/*
653		 * skip tests when desired generator doesn't match
654		 */
655		if (generator_wanted > 0 &&
656		    generator_wanted != generator_known) {
657			debug2("%10u: generator %d != %d",
658			    count_in, generator_known, generator_wanted);
659			continue;
660		}
661
662		/*
663		 * Primes with no known generator are useless for DH, so
664		 * skip those.
665		 */
666		if (generator_known == 0) {
667			debug2("%10u: no known generator", count_in);
668			continue;
669		}
670
671		count_possible++;
672
673		/*
674		 * The (1/4)^N performance bound on Miller-Rabin is
675		 * extremely pessimistic, so don't spend a lot of time
676		 * really verifying that q is prime until after we know
677		 * that p is also prime. A single pass will weed out the
678		 * vast majority of composite q's.
679		 */
680		if (BN_is_prime_ex(q, 1, ctx, NULL) <= 0) {
681			debug("%10u: q failed first possible prime test",
682			    count_in);
683			continue;
684		}
685
686		/*
687		 * q is possibly prime, so go ahead and really make sure
688		 * that p is prime. If it is, then we can go back and do
689		 * the same for q. If p is composite, chances are that
690		 * will show up on the first Rabin-Miller iteration so it
691		 * doesn't hurt to specify a high iteration count.
692		 */
693		if (!BN_is_prime_ex(p, trials, ctx, NULL)) {
694			debug("%10u: p is not prime", count_in);
695			continue;
696		}
697		debug("%10u: p is almost certainly prime", count_in);
698
699		/* recheck q more rigorously */
700		if (!BN_is_prime_ex(q, trials - 1, ctx, NULL)) {
701			debug("%10u: q is not prime", count_in);
702			continue;
703		}
704		debug("%10u: q is almost certainly prime", count_in);
705
706		if (qfileout(out, MODULI_TYPE_SAFE,
707		    in_tests | MODULI_TESTS_MILLER_RABIN,
708		    in_tries, in_size, generator_known, p)) {
709			res = -1;
710			break;
711		}
712
713		count_out++;
714	}
715
716	time(&time_stop);
717	xfree(lp);
718	BN_free(p);
719	BN_free(q);
720	BN_CTX_free(ctx);
721
722	if (checkpoint_file != NULL)
723		unlink(checkpoint_file);
724
725	logit("%.24s Found %u safe primes of %u candidates in %ld seconds",
726	    ctime(&time_stop), count_out, count_possible,
727	    (long) (time_stop - time_start));
728
729	return (res);
730}
731