[BACK]Return to moduli.c CVS log [TXT][DIR] Up to [local] / src / usr.bin / ssh

Annotation of src/usr.bin/ssh/moduli.c, Revision 1.17

1.17    ! stevesk     1: /* $OpenBSD: moduli.c,v 1.16 2006/07/26 13:57:17 stevesk 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:
                     40: #include "includes.h"
1.14      stevesk    41:
                     42: #include <sys/types.h>
                     43:
                     44: #include <openssl/bn.h>
                     45:
1.17    ! stevesk    46: #include <stdio.h>
1.16      stevesk    47: #include <stdlib.h>
1.15      stevesk    48: #include <string.h>
1.14      stevesk    49: #include <time.h>
                     50:
1.1       djm        51: #include "xmalloc.h"
                     52: #include "log.h"
                     53:
                     54: /*
                     55:  * File output defines
                     56:  */
                     57:
                     58: /* need line long enough for largest moduli plus headers */
1.9       deraadt    59: #define QLINESIZE              (100+8192)
1.1       djm        60:
                     61: /* Type: decimal.
                     62:  * Specifies the internal structure of the prime modulus.
                     63:  */
1.9       deraadt    64: #define QTYPE_UNKNOWN          (0)
                     65: #define QTYPE_UNSTRUCTURED     (1)
                     66: #define QTYPE_SAFE             (2)
1.10      dtucker    67: #define QTYPE_SCHNORR          (3)
1.9       deraadt    68: #define QTYPE_SOPHIE_GERMAIN   (4)
                     69: #define QTYPE_STRONG           (5)
1.1       djm        70:
                     71: /* Tests: decimal (bit field).
                     72:  * Specifies the methods used in checking for primality.
                     73:  * Usually, more than one test is used.
                     74:  */
1.9       deraadt    75: #define QTEST_UNTESTED         (0x00)
                     76: #define QTEST_COMPOSITE                (0x01)
                     77: #define QTEST_SIEVE            (0x02)
                     78: #define QTEST_MILLER_RABIN     (0x04)
                     79: #define QTEST_JACOBI           (0x08)
                     80: #define QTEST_ELLIPTIC         (0x10)
1.1       djm        81:
1.5       djm        82: /*
                     83:  * Size: decimal.
1.1       djm        84:  * Specifies the number of the most significant bit (0 to M).
1.5       djm        85:  * WARNING: internally, usually 1 to N.
1.1       djm        86:  */
1.9       deraadt    87: #define QSIZE_MINIMUM          (511)
1.1       djm        88:
                     89: /*
                     90:  * Prime sieving defines
                     91:  */
                     92:
                     93: /* Constant: assuming 8 bit bytes and 32 bit words */
1.9       deraadt    94: #define SHIFT_BIT      (3)
                     95: #define SHIFT_BYTE     (2)
                     96: #define SHIFT_WORD     (SHIFT_BIT+SHIFT_BYTE)
                     97: #define SHIFT_MEGABYTE (20)
                     98: #define SHIFT_MEGAWORD (SHIFT_MEGABYTE-SHIFT_BYTE)
1.1       djm        99:
                    100: /*
1.7       djm       101:  * Using virtual memory can cause thrashing.  This should be the largest
                    102:  * number that is supported without a large amount of disk activity --
                    103:  * that would increase the run time from hours to days or weeks!
                    104:  */
1.9       deraadt   105: #define LARGE_MINIMUM  (8UL)   /* megabytes */
1.7       djm       106:
                    107: /*
                    108:  * Do not increase this number beyond the unsigned integer bit size.
                    109:  * Due to a multiple of 4, it must be LESS than 128 (yielding 2**30 bits).
                    110:  */
1.9       deraadt   111: #define LARGE_MAXIMUM  (127UL) /* megabytes */
1.7       djm       112:
                    113: /*
1.1       djm       114:  * Constant: when used with 32-bit integers, the largest sieve prime
                    115:  * has to be less than 2**32.
                    116:  */
1.9       deraadt   117: #define SMALL_MAXIMUM  (0xffffffffUL)
1.1       djm       118:
                    119: /* Constant: can sieve all primes less than 2**32, as 65537**2 > 2**32-1. */
1.9       deraadt   120: #define TINY_NUMBER    (1UL<<16)
1.1       djm       121:
                    122: /* Ensure enough bit space for testing 2*q. */
1.12      djm       123: #define TEST_MAXIMUM   (1UL<<16)
                    124: #define TEST_MINIMUM   (QSIZE_MINIMUM + 1)
                    125: /* real TEST_MINIMUM   (1UL << (SHIFT_WORD - TEST_POWER)) */
                    126: #define TEST_POWER     (3)     /* 2**n, n < SHIFT_WORD */
1.1       djm       127:
                    128: /* bit operations on 32-bit words */
1.12      djm       129: #define BIT_CLEAR(a,n) ((a)[(n)>>SHIFT_WORD] &= ~(1L << ((n) & 31)))
                    130: #define BIT_SET(a,n)   ((a)[(n)>>SHIFT_WORD] |= (1L << ((n) & 31)))
                    131: #define BIT_TEST(a,n)  ((a)[(n)>>SHIFT_WORD] & (1L << ((n) & 31)))
1.1       djm       132:
                    133: /*
                    134:  * Prime testing defines
                    135:  */
                    136:
1.7       djm       137: /* Minimum number of primality tests to perform */
1.12      djm       138: #define TRIAL_MINIMUM  (4)
1.7       djm       139:
1.1       djm       140: /*
                    141:  * Sieving data (XXX - move to struct)
                    142:  */
                    143:
                    144: /* sieve 2**16 */
                    145: static u_int32_t *TinySieve, tinybits;
                    146:
                    147: /* sieve 2**30 in 2**16 parts */
                    148: static u_int32_t *SmallSieve, smallbits, smallbase;
                    149:
                    150: /* sieve relative to the initial value */
                    151: static u_int32_t *LargeSieve, largewords, largetries, largenumbers;
                    152: static u_int32_t largebits, largememory;       /* megabytes */
                    153: static BIGNUM *largebase;
                    154:
1.11      avsm      155: int gen_candidates(FILE *, u_int32_t, u_int32_t, BIGNUM *);
1.8       markus    156: int prime_test(FILE *, FILE *, u_int32_t, u_int32_t);
1.1       djm       157:
                    158: /*
                    159:  * print moduli out in consistent form,
                    160:  */
                    161: static int
                    162: qfileout(FILE * ofile, u_int32_t otype, u_int32_t otests, u_int32_t otries,
                    163:     u_int32_t osize, u_int32_t ogenerator, BIGNUM * omodulus)
                    164: {
                    165:        struct tm *gtm;
                    166:        time_t time_now;
                    167:        int res;
                    168:
                    169:        time(&time_now);
                    170:        gtm = gmtime(&time_now);
1.2       djm       171:
1.1       djm       172:        res = fprintf(ofile, "%04d%02d%02d%02d%02d%02d %u %u %u %u %x ",
                    173:            gtm->tm_year + 1900, gtm->tm_mon + 1, gtm->tm_mday,
                    174:            gtm->tm_hour, gtm->tm_min, gtm->tm_sec,
                    175:            otype, otests, otries, osize, ogenerator);
                    176:
                    177:        if (res < 0)
                    178:                return (-1);
                    179:
                    180:        if (BN_print_fp(ofile, omodulus) < 1)
                    181:                return (-1);
                    182:
                    183:        res = fprintf(ofile, "\n");
                    184:        fflush(ofile);
                    185:
                    186:        return (res > 0 ? 0 : -1);
                    187: }
                    188:
                    189:
                    190: /*
                    191:  ** Sieve p's and q's with small factors
                    192:  */
                    193: static void
                    194: sieve_large(u_int32_t s)
                    195: {
                    196:        u_int32_t r, u;
                    197:
1.5       djm       198:        debug3("sieve_large %u", s);
1.1       djm       199:        largetries++;
                    200:        /* r = largebase mod s */
                    201:        r = BN_mod_word(largebase, s);
                    202:        if (r == 0)
                    203:                u = 0; /* s divides into largebase exactly */
                    204:        else
                    205:                u = s - r; /* largebase+u is first entry divisible by s */
                    206:
                    207:        if (u < largebits * 2) {
                    208:                /*
                    209:                 * The sieve omits p's and q's divisible by 2, so ensure that
                    210:                 * largebase+u is odd. Then, step through the sieve in
                    211:                 * increments of 2*s
                    212:                 */
                    213:                if (u & 0x1)
                    214:                        u += s; /* Make largebase+u odd, and u even */
                    215:
                    216:                /* Mark all multiples of 2*s */
                    217:                for (u /= 2; u < largebits; u += s)
                    218:                        BIT_SET(LargeSieve, u);
                    219:        }
                    220:
                    221:        /* r = p mod s */
                    222:        r = (2 * r + 1) % s;
                    223:        if (r == 0)
                    224:                u = 0; /* s divides p exactly */
                    225:        else
                    226:                u = s - r; /* p+u is first entry divisible by s */
                    227:
                    228:        if (u < largebits * 4) {
                    229:                /*
                    230:                 * The sieve omits p's divisible by 4, so ensure that
                    231:                 * largebase+u is not. Then, step through the sieve in
                    232:                 * increments of 4*s
                    233:                 */
                    234:                while (u & 0x3) {
                    235:                        if (SMALL_MAXIMUM - u < s)
                    236:                                return;
                    237:                        u += s;
                    238:                }
                    239:
                    240:                /* Mark all multiples of 4*s */
                    241:                for (u /= 4; u < largebits; u += s)
                    242:                        BIT_SET(LargeSieve, u);
                    243:        }
                    244: }
                    245:
                    246: /*
1.6       djm       247:  * list candidates for Sophie-Germain primes (where q = (p-1)/2)
1.1       djm       248:  * to standard output.
                    249:  * The list is checked against small known primes (less than 2**30).
                    250:  */
                    251: int
1.11      avsm      252: gen_candidates(FILE *out, u_int32_t memory, u_int32_t power, BIGNUM *start)
1.1       djm       253: {
                    254:        BIGNUM *q;
                    255:        u_int32_t j, r, s, t;
                    256:        u_int32_t smallwords = TINY_NUMBER >> 6;
                    257:        u_int32_t tinywords = TINY_NUMBER >> 6;
                    258:        time_t time_start, time_stop;
1.11      avsm      259:        u_int32_t i;
                    260:        int ret = 0;
1.1       djm       261:
                    262:        largememory = memory;
                    263:
1.7       djm       264:        if (memory != 0 &&
1.12      djm       265:            (memory < LARGE_MINIMUM || memory > LARGE_MAXIMUM)) {
1.7       djm       266:                error("Invalid memory amount (min %ld, max %ld)",
                    267:                    LARGE_MINIMUM, LARGE_MAXIMUM);
                    268:                return (-1);
                    269:        }
                    270:
1.1       djm       271:        /*
1.2       djm       272:         * Set power to the length in bits of the prime to be generated.
                    273:         * This is changed to 1 less than the desired safe prime moduli p.
                    274:         */
1.1       djm       275:        if (power > TEST_MAXIMUM) {
                    276:                error("Too many bits: %u > %lu", power, TEST_MAXIMUM);
                    277:                return (-1);
                    278:        } else if (power < TEST_MINIMUM) {
                    279:                error("Too few bits: %u < %u", power, TEST_MINIMUM);
                    280:                return (-1);
                    281:        }
                    282:        power--; /* decrement before squaring */
                    283:
                    284:        /*
1.2       djm       285:         * The density of ordinary primes is on the order of 1/bits, so the
                    286:         * density of safe primes should be about (1/bits)**2. Set test range
                    287:         * to something well above bits**2 to be reasonably sure (but not
                    288:         * guaranteed) of catching at least one safe prime.
1.1       djm       289:         */
                    290:        largewords = ((power * power) >> (SHIFT_WORD - TEST_POWER));
                    291:
                    292:        /*
1.2       djm       293:         * Need idea of how much memory is available. We don't have to use all
                    294:         * of it.
1.1       djm       295:         */
                    296:        if (largememory > LARGE_MAXIMUM) {
                    297:                logit("Limited memory: %u MB; limit %lu MB",
                    298:                    largememory, LARGE_MAXIMUM);
                    299:                largememory = LARGE_MAXIMUM;
                    300:        }
                    301:
                    302:        if (largewords <= (largememory << SHIFT_MEGAWORD)) {
                    303:                logit("Increased memory: %u MB; need %u bytes",
                    304:                    largememory, (largewords << SHIFT_BYTE));
                    305:                largewords = (largememory << SHIFT_MEGAWORD);
                    306:        } else if (largememory > 0) {
                    307:                logit("Decreased memory: %u MB; want %u bytes",
                    308:                    largememory, (largewords << SHIFT_BYTE));
                    309:                largewords = (largememory << SHIFT_MEGAWORD);
                    310:        }
                    311:
1.13      djm       312:        TinySieve = xcalloc(tinywords, sizeof(u_int32_t));
1.1       djm       313:        tinybits = tinywords << SHIFT_WORD;
                    314:
1.13      djm       315:        SmallSieve = xcalloc(smallwords, sizeof(u_int32_t));
1.1       djm       316:        smallbits = smallwords << SHIFT_WORD;
                    317:
                    318:        /*
                    319:         * dynamically determine available memory
                    320:         */
                    321:        while ((LargeSieve = calloc(largewords, sizeof(u_int32_t))) == NULL)
                    322:                largewords -= (1L << (SHIFT_MEGAWORD - 2)); /* 1/4 MB chunks */
                    323:
                    324:        largebits = largewords << SHIFT_WORD;
                    325:        largenumbers = largebits * 2;   /* even numbers excluded */
                    326:
                    327:        /* validation check: count the number of primes tried */
                    328:        largetries = 0;
                    329:        q = BN_new();
                    330:
                    331:        /*
1.2       djm       332:         * Generate random starting point for subprime search, or use
                    333:         * specified parameter.
1.1       djm       334:         */
                    335:        largebase = BN_new();
                    336:        if (start == NULL)
                    337:                BN_rand(largebase, power, 1, 1);
                    338:        else
                    339:                BN_copy(largebase, start);
                    340:
                    341:        /* ensure odd */
                    342:        BN_set_bit(largebase, 0);
                    343:
                    344:        time(&time_start);
                    345:
1.2       djm       346:        logit("%.24s Sieve next %u plus %u-bit", ctime(&time_start),
1.1       djm       347:            largenumbers, power);
                    348:        debug2("start point: 0x%s", BN_bn2hex(largebase));
                    349:
                    350:        /*
1.2       djm       351:         * TinySieve
                    352:         */
1.1       djm       353:        for (i = 0; i < tinybits; i++) {
                    354:                if (BIT_TEST(TinySieve, i))
                    355:                        continue; /* 2*i+3 is composite */
                    356:
                    357:                /* The next tiny prime */
                    358:                t = 2 * i + 3;
                    359:
                    360:                /* Mark all multiples of t */
                    361:                for (j = i + t; j < tinybits; j += t)
                    362:                        BIT_SET(TinySieve, j);
                    363:
                    364:                sieve_large(t);
                    365:        }
                    366:
                    367:        /*
1.2       djm       368:         * Start the small block search at the next possible prime. To avoid
                    369:         * fencepost errors, the last pass is skipped.
                    370:         */
1.1       djm       371:        for (smallbase = TINY_NUMBER + 3;
1.12      djm       372:            smallbase < (SMALL_MAXIMUM - TINY_NUMBER);
                    373:            smallbase += TINY_NUMBER) {
1.1       djm       374:                for (i = 0; i < tinybits; i++) {
                    375:                        if (BIT_TEST(TinySieve, i))
                    376:                                continue; /* 2*i+3 is composite */
                    377:
                    378:                        /* The next tiny prime */
                    379:                        t = 2 * i + 3;
                    380:                        r = smallbase % t;
                    381:
                    382:                        if (r == 0) {
                    383:                                s = 0; /* t divides into smallbase exactly */
                    384:                        } else {
                    385:                                /* smallbase+s is first entry divisible by t */
                    386:                                s = t - r;
                    387:                        }
                    388:
                    389:                        /*
                    390:                         * The sieve omits even numbers, so ensure that
                    391:                         * smallbase+s is odd. Then, step through the sieve
                    392:                         * in increments of 2*t
                    393:                         */
                    394:                        if (s & 1)
                    395:                                s += t; /* Make smallbase+s odd, and s even */
                    396:
                    397:                        /* Mark all multiples of 2*t */
                    398:                        for (s /= 2; s < smallbits; s += t)
                    399:                                BIT_SET(SmallSieve, s);
                    400:                }
                    401:
                    402:                /*
1.2       djm       403:                 * SmallSieve
                    404:                 */
1.1       djm       405:                for (i = 0; i < smallbits; i++) {
                    406:                        if (BIT_TEST(SmallSieve, i))
                    407:                                continue; /* 2*i+smallbase is composite */
                    408:
                    409:                        /* The next small prime */
                    410:                        sieve_large((2 * i) + smallbase);
                    411:                }
                    412:
                    413:                memset(SmallSieve, 0, smallwords << SHIFT_BYTE);
                    414:        }
                    415:
                    416:        time(&time_stop);
                    417:
                    418:        logit("%.24s Sieved with %u small primes in %ld seconds",
                    419:            ctime(&time_stop), largetries, (long) (time_stop - time_start));
                    420:
                    421:        for (j = r = 0; j < largebits; j++) {
                    422:                if (BIT_TEST(LargeSieve, j))
                    423:                        continue; /* Definitely composite, skip */
                    424:
                    425:                debug2("test q = largebase+%u", 2 * j);
                    426:                BN_set_word(q, 2 * j);
                    427:                BN_add(q, q, largebase);
1.6       djm       428:                if (qfileout(out, QTYPE_SOPHIE_GERMAIN, QTEST_SIEVE,
1.1       djm       429:                    largetries, (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:        xfree(LargeSieve);
                    440:        xfree(SmallSieve);
                    441:        xfree(TinySieve);
                    442:
                    443:        logit("%.24s Found %u candidates", ctime(&time_stop), r);
                    444:
                    445:        return (ret);
                    446: }
                    447:
                    448: /*
                    449:  * perform a Miller-Rabin primality test
                    450:  * on the list of candidates
                    451:  * (checking both q and p)
                    452:  * The result is a list of so-call "safe" primes
                    453:  */
                    454: int
1.7       djm       455: prime_test(FILE *in, FILE *out, u_int32_t trials, u_int32_t generator_wanted)
1.1       djm       456: {
                    457:        BIGNUM *q, *p, *a;
                    458:        BN_CTX *ctx;
                    459:        char *cp, *lp;
                    460:        u_int32_t count_in = 0, count_out = 0, count_possible = 0;
                    461:        u_int32_t generator_known, in_tests, in_tries, in_type, in_size;
                    462:        time_t time_start, time_stop;
                    463:        int res;
1.7       djm       464:
                    465:        if (trials < TRIAL_MINIMUM) {
                    466:                error("Minimum primality trials is %d", TRIAL_MINIMUM);
                    467:                return (-1);
                    468:        }
1.1       djm       469:
                    470:        time(&time_start);
                    471:
                    472:        p = BN_new();
                    473:        q = BN_new();
                    474:        ctx = BN_CTX_new();
                    475:
                    476:        debug2("%.24s Final %u Miller-Rabin trials (%x generator)",
                    477:            ctime(&time_start), trials, generator_wanted);
                    478:
                    479:        res = 0;
                    480:        lp = xmalloc(QLINESIZE + 1);
                    481:        while (fgets(lp, QLINESIZE, in) != NULL) {
                    482:                int ll = strlen(lp);
                    483:
                    484:                count_in++;
                    485:                if (ll < 14 || *lp == '!' || *lp == '#') {
                    486:                        debug2("%10u: comment or short line", count_in);
                    487:                        continue;
                    488:                }
                    489:
                    490:                /* XXX - fragile parser */
                    491:                /* time */
                    492:                cp = &lp[14];   /* (skip) */
                    493:
                    494:                /* type */
                    495:                in_type = strtoul(cp, &cp, 10);
                    496:
                    497:                /* tests */
                    498:                in_tests = strtoul(cp, &cp, 10);
                    499:
                    500:                if (in_tests & QTEST_COMPOSITE) {
                    501:                        debug2("%10u: known composite", count_in);
                    502:                        continue;
                    503:                }
1.5       djm       504:
1.1       djm       505:                /* tries */
                    506:                in_tries = strtoul(cp, &cp, 10);
                    507:
                    508:                /* size (most significant bit) */
                    509:                in_size = strtoul(cp, &cp, 10);
                    510:
                    511:                /* generator (hex) */
                    512:                generator_known = strtoul(cp, &cp, 16);
                    513:
                    514:                /* Skip white space */
                    515:                cp += strspn(cp, " ");
                    516:
                    517:                /* modulus (hex) */
                    518:                switch (in_type) {
1.6       djm       519:                case QTYPE_SOPHIE_GERMAIN:
                    520:                        debug2("%10u: (%u) Sophie-Germain", count_in, in_type);
1.1       djm       521:                        a = q;
                    522:                        BN_hex2bn(&a, cp);
                    523:                        /* p = 2*q + 1 */
                    524:                        BN_lshift(p, q, 1);
                    525:                        BN_add_word(p, 1);
                    526:                        in_size += 1;
                    527:                        generator_known = 0;
                    528:                        break;
1.5       djm       529:                case QTYPE_UNSTRUCTURED:
                    530:                case QTYPE_SAFE:
1.10      dtucker   531:                case QTYPE_SCHNORR:
1.5       djm       532:                case QTYPE_STRONG:
                    533:                case QTYPE_UNKNOWN:
1.1       djm       534:                        debug2("%10u: (%u)", count_in, in_type);
                    535:                        a = p;
                    536:                        BN_hex2bn(&a, cp);
                    537:                        /* q = (p-1) / 2 */
                    538:                        BN_rshift(q, p, 1);
                    539:                        break;
1.5       djm       540:                default:
                    541:                        debug2("Unknown prime type");
                    542:                        break;
1.1       djm       543:                }
                    544:
                    545:                /*
                    546:                 * due to earlier inconsistencies in interpretation, check
                    547:                 * the proposed bit size.
                    548:                 */
1.11      avsm      549:                if ((u_int32_t)BN_num_bits(p) != (in_size + 1)) {
1.1       djm       550:                        debug2("%10u: bit size %u mismatch", count_in, in_size);
                    551:                        continue;
                    552:                }
                    553:                if (in_size < QSIZE_MINIMUM) {
                    554:                        debug2("%10u: bit size %u too short", count_in, in_size);
                    555:                        continue;
                    556:                }
                    557:
                    558:                if (in_tests & QTEST_MILLER_RABIN)
                    559:                        in_tries += trials;
                    560:                else
                    561:                        in_tries = trials;
1.5       djm       562:
1.1       djm       563:                /*
                    564:                 * guess unknown generator
                    565:                 */
                    566:                if (generator_known == 0) {
                    567:                        if (BN_mod_word(p, 24) == 11)
                    568:                                generator_known = 2;
                    569:                        else if (BN_mod_word(p, 12) == 5)
                    570:                                generator_known = 3;
                    571:                        else {
                    572:                                u_int32_t r = BN_mod_word(p, 10);
                    573:
1.5       djm       574:                                if (r == 3 || r == 7)
1.1       djm       575:                                        generator_known = 5;
                    576:                        }
                    577:                }
                    578:                /*
                    579:                 * skip tests when desired generator doesn't match
                    580:                 */
                    581:                if (generator_wanted > 0 &&
                    582:                    generator_wanted != generator_known) {
                    583:                        debug2("%10u: generator %d != %d",
                    584:                            count_in, generator_known, generator_wanted);
1.4       dtucker   585:                        continue;
                    586:                }
                    587:
                    588:                /*
                    589:                 * Primes with no known generator are useless for DH, so
                    590:                 * skip those.
                    591:                 */
                    592:                if (generator_known == 0) {
                    593:                        debug2("%10u: no known generator", count_in);
1.1       djm       594:                        continue;
                    595:                }
                    596:
                    597:                count_possible++;
                    598:
                    599:                /*
1.2       djm       600:                 * The (1/4)^N performance bound on Miller-Rabin is
                    601:                 * extremely pessimistic, so don't spend a lot of time
                    602:                 * really verifying that q is prime until after we know
                    603:                 * that p is also prime. A single pass will weed out the
1.1       djm       604:                 * vast majority of composite q's.
                    605:                 */
                    606:                if (BN_is_prime(q, 1, NULL, ctx, NULL) <= 0) {
1.5       djm       607:                        debug("%10u: q failed first possible prime test",
1.1       djm       608:                            count_in);
                    609:                        continue;
                    610:                }
1.2       djm       611:
1.1       djm       612:                /*
1.2       djm       613:                 * q is possibly prime, so go ahead and really make sure
                    614:                 * that p is prime. If it is, then we can go back and do
                    615:                 * the same for q. If p is composite, chances are that
1.1       djm       616:                 * will show up on the first Rabin-Miller iteration so it
                    617:                 * doesn't hurt to specify a high iteration count.
                    618:                 */
                    619:                if (!BN_is_prime(p, trials, NULL, ctx, NULL)) {
1.5       djm       620:                        debug("%10u: p is not prime", count_in);
1.1       djm       621:                        continue;
                    622:                }
                    623:                debug("%10u: p is almost certainly prime", count_in);
                    624:
                    625:                /* recheck q more rigorously */
                    626:                if (!BN_is_prime(q, trials - 1, NULL, ctx, NULL)) {
                    627:                        debug("%10u: q is not prime", count_in);
                    628:                        continue;
                    629:                }
                    630:                debug("%10u: q is almost certainly prime", count_in);
                    631:
1.2       djm       632:                if (qfileout(out, QTYPE_SAFE, (in_tests | QTEST_MILLER_RABIN),
1.1       djm       633:                    in_tries, in_size, generator_known, p)) {
                    634:                        res = -1;
                    635:                        break;
                    636:                }
                    637:
                    638:                count_out++;
                    639:        }
                    640:
                    641:        time(&time_stop);
                    642:        xfree(lp);
                    643:        BN_free(p);
                    644:        BN_free(q);
                    645:        BN_CTX_free(ctx);
                    646:
                    647:        logit("%.24s Found %u safe primes of %u candidates in %ld seconds",
1.2       djm       648:            ctime(&time_stop), count_out, count_possible,
1.1       djm       649:            (long) (time_stop - time_start));
                    650:
                    651:        return (res);
                    652: }