xref: /openssh-portable/moduli.c (revision 8142fcaf)
1 /* $OpenBSD: moduli.c,v 1.35 2019/07/03 03:24:02 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 %lld seconds",
416 	    ctime(&time_stop), largetries, (long 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 < 0 || 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, is_prime;
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 {
720 				u_int32_t r = BN_mod_word(p, 10);
721 
722 				if (r == 3 || r == 7)
723 					generator_known = 5;
724 			}
725 		}
726 		/*
727 		 * skip tests when desired generator doesn't match
728 		 */
729 		if (generator_wanted > 0 &&
730 		    generator_wanted != generator_known) {
731 			debug2("%10u: generator %d != %d",
732 			    count_in, generator_known, generator_wanted);
733 			continue;
734 		}
735 
736 		/*
737 		 * Primes with no known generator are useless for DH, so
738 		 * skip those.
739 		 */
740 		if (generator_known == 0) {
741 			debug2("%10u: no known generator", count_in);
742 			continue;
743 		}
744 
745 		count_possible++;
746 
747 		/*
748 		 * The (1/4)^N performance bound on Miller-Rabin is
749 		 * extremely pessimistic, so don't spend a lot of time
750 		 * really verifying that q is prime until after we know
751 		 * that p is also prime. A single pass will weed out the
752 		 * vast majority of composite q's.
753 		 */
754 		is_prime = BN_is_prime_ex(q, 1, ctx, NULL);
755 		if (is_prime < 0)
756 			fatal("BN_is_prime_ex failed");
757 		if (is_prime == 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 		is_prime = BN_is_prime_ex(p, trials, ctx, NULL);
771 		if (is_prime < 0)
772 			fatal("BN_is_prime_ex failed");
773 		if (is_prime == 0) {
774 			debug("%10u: p is not prime", count_in);
775 			continue;
776 		}
777 		debug("%10u: p is almost certainly prime", count_in);
778 
779 		/* recheck q more rigorously */
780 		is_prime = BN_is_prime_ex(q, trials - 1, ctx, NULL);
781 		if (is_prime < 0)
782 			fatal("BN_is_prime_ex failed");
783 		if (is_prime == 0) {
784 			debug("%10u: q is not prime", count_in);
785 			continue;
786 		}
787 		debug("%10u: q is almost certainly prime", count_in);
788 
789 		if (qfileout(out, MODULI_TYPE_SAFE,
790 		    in_tests | MODULI_TESTS_MILLER_RABIN,
791 		    in_tries, in_size, generator_known, p)) {
792 			res = -1;
793 			break;
794 		}
795 
796 		count_out++;
797 	}
798 
799 	time(&time_stop);
800 	free(lp);
801 	BN_free(p);
802 	BN_free(q);
803 	BN_CTX_free(ctx);
804 
805 	if (checkpoint_file != NULL)
806 		unlink(checkpoint_file);
807 
808 	logit("%.24s Found %u safe primes of %u candidates in %ld seconds",
809 	    ctime(&time_stop), count_out, count_possible,
810 	    (long) (time_stop - time_start));
811 
812 	return (res);
813 }
814 
815 #endif /* WITH_OPENSSL */
816