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Annotation of src/usr.bin/ssh/moduli.c, Revision 1.15

1.15    ! stevesk     1: /* $OpenBSD: moduli.c,v 1.14 2006/07/22 19:08:54 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:
1.15    ! stevesk    46: #include <string.h>
1.14      stevesk    47: #include <time.h>
                     48:
1.1       djm        49: #include "xmalloc.h"
                     50: #include "log.h"
                     51:
                     52: /*
                     53:  * File output defines
                     54:  */
                     55:
                     56: /* need line long enough for largest moduli plus headers */
1.9       deraadt    57: #define QLINESIZE              (100+8192)
1.1       djm        58:
                     59: /* Type: decimal.
                     60:  * Specifies the internal structure of the prime modulus.
                     61:  */
1.9       deraadt    62: #define QTYPE_UNKNOWN          (0)
                     63: #define QTYPE_UNSTRUCTURED     (1)
                     64: #define QTYPE_SAFE             (2)
1.10      dtucker    65: #define QTYPE_SCHNORR          (3)
1.9       deraadt    66: #define QTYPE_SOPHIE_GERMAIN   (4)
                     67: #define QTYPE_STRONG           (5)
1.1       djm        68:
                     69: /* Tests: decimal (bit field).
                     70:  * Specifies the methods used in checking for primality.
                     71:  * Usually, more than one test is used.
                     72:  */
1.9       deraadt    73: #define QTEST_UNTESTED         (0x00)
                     74: #define QTEST_COMPOSITE                (0x01)
                     75: #define QTEST_SIEVE            (0x02)
                     76: #define QTEST_MILLER_RABIN     (0x04)
                     77: #define QTEST_JACOBI           (0x08)
                     78: #define QTEST_ELLIPTIC         (0x10)
1.1       djm        79:
1.5       djm        80: /*
                     81:  * Size: decimal.
1.1       djm        82:  * Specifies the number of the most significant bit (0 to M).
1.5       djm        83:  * WARNING: internally, usually 1 to N.
1.1       djm        84:  */
1.9       deraadt    85: #define QSIZE_MINIMUM          (511)
1.1       djm        86:
                     87: /*
                     88:  * Prime sieving defines
                     89:  */
                     90:
                     91: /* Constant: assuming 8 bit bytes and 32 bit words */
1.9       deraadt    92: #define SHIFT_BIT      (3)
                     93: #define SHIFT_BYTE     (2)
                     94: #define SHIFT_WORD     (SHIFT_BIT+SHIFT_BYTE)
                     95: #define SHIFT_MEGABYTE (20)
                     96: #define SHIFT_MEGAWORD (SHIFT_MEGABYTE-SHIFT_BYTE)
1.1       djm        97:
                     98: /*
1.7       djm        99:  * Using virtual memory can cause thrashing.  This should be the largest
                    100:  * number that is supported without a large amount of disk activity --
                    101:  * that would increase the run time from hours to days or weeks!
                    102:  */
1.9       deraadt   103: #define LARGE_MINIMUM  (8UL)   /* megabytes */
1.7       djm       104:
                    105: /*
                    106:  * Do not increase this number beyond the unsigned integer bit size.
                    107:  * Due to a multiple of 4, it must be LESS than 128 (yielding 2**30 bits).
                    108:  */
1.9       deraadt   109: #define LARGE_MAXIMUM  (127UL) /* megabytes */
1.7       djm       110:
                    111: /*
1.1       djm       112:  * Constant: when used with 32-bit integers, the largest sieve prime
                    113:  * has to be less than 2**32.
                    114:  */
1.9       deraadt   115: #define SMALL_MAXIMUM  (0xffffffffUL)
1.1       djm       116:
                    117: /* Constant: can sieve all primes less than 2**32, as 65537**2 > 2**32-1. */
1.9       deraadt   118: #define TINY_NUMBER    (1UL<<16)
1.1       djm       119:
                    120: /* Ensure enough bit space for testing 2*q. */
1.12      djm       121: #define TEST_MAXIMUM   (1UL<<16)
                    122: #define TEST_MINIMUM   (QSIZE_MINIMUM + 1)
                    123: /* real TEST_MINIMUM   (1UL << (SHIFT_WORD - TEST_POWER)) */
                    124: #define TEST_POWER     (3)     /* 2**n, n < SHIFT_WORD */
1.1       djm       125:
                    126: /* bit operations on 32-bit words */
1.12      djm       127: #define BIT_CLEAR(a,n) ((a)[(n)>>SHIFT_WORD] &= ~(1L << ((n) & 31)))
                    128: #define BIT_SET(a,n)   ((a)[(n)>>SHIFT_WORD] |= (1L << ((n) & 31)))
                    129: #define BIT_TEST(a,n)  ((a)[(n)>>SHIFT_WORD] & (1L << ((n) & 31)))
1.1       djm       130:
                    131: /*
                    132:  * Prime testing defines
                    133:  */
                    134:
1.7       djm       135: /* Minimum number of primality tests to perform */
1.12      djm       136: #define TRIAL_MINIMUM  (4)
1.7       djm       137:
1.1       djm       138: /*
                    139:  * Sieving data (XXX - move to struct)
                    140:  */
                    141:
                    142: /* sieve 2**16 */
                    143: static u_int32_t *TinySieve, tinybits;
                    144:
                    145: /* sieve 2**30 in 2**16 parts */
                    146: static u_int32_t *SmallSieve, smallbits, smallbase;
                    147:
                    148: /* sieve relative to the initial value */
                    149: static u_int32_t *LargeSieve, largewords, largetries, largenumbers;
                    150: static u_int32_t largebits, largememory;       /* megabytes */
                    151: static BIGNUM *largebase;
                    152:
1.11      avsm      153: int gen_candidates(FILE *, u_int32_t, u_int32_t, BIGNUM *);
1.8       markus    154: int prime_test(FILE *, FILE *, u_int32_t, u_int32_t);
1.1       djm       155:
                    156: /*
                    157:  * print moduli out in consistent form,
                    158:  */
                    159: static int
                    160: qfileout(FILE * ofile, u_int32_t otype, u_int32_t otests, u_int32_t otries,
                    161:     u_int32_t osize, u_int32_t ogenerator, BIGNUM * omodulus)
                    162: {
                    163:        struct tm *gtm;
                    164:        time_t time_now;
                    165:        int res;
                    166:
                    167:        time(&time_now);
                    168:        gtm = gmtime(&time_now);
1.2       djm       169:
1.1       djm       170:        res = fprintf(ofile, "%04d%02d%02d%02d%02d%02d %u %u %u %u %x ",
                    171:            gtm->tm_year + 1900, gtm->tm_mon + 1, gtm->tm_mday,
                    172:            gtm->tm_hour, gtm->tm_min, gtm->tm_sec,
                    173:            otype, otests, otries, osize, ogenerator);
                    174:
                    175:        if (res < 0)
                    176:                return (-1);
                    177:
                    178:        if (BN_print_fp(ofile, omodulus) < 1)
                    179:                return (-1);
                    180:
                    181:        res = fprintf(ofile, "\n");
                    182:        fflush(ofile);
                    183:
                    184:        return (res > 0 ? 0 : -1);
                    185: }
                    186:
                    187:
                    188: /*
                    189:  ** Sieve p's and q's with small factors
                    190:  */
                    191: static void
                    192: sieve_large(u_int32_t s)
                    193: {
                    194:        u_int32_t r, u;
                    195:
1.5       djm       196:        debug3("sieve_large %u", s);
1.1       djm       197:        largetries++;
                    198:        /* r = largebase mod s */
                    199:        r = BN_mod_word(largebase, s);
                    200:        if (r == 0)
                    201:                u = 0; /* s divides into largebase exactly */
                    202:        else
                    203:                u = s - r; /* largebase+u is first entry divisible by s */
                    204:
                    205:        if (u < largebits * 2) {
                    206:                /*
                    207:                 * The sieve omits p's and q's divisible by 2, so ensure that
                    208:                 * largebase+u is odd. Then, step through the sieve in
                    209:                 * increments of 2*s
                    210:                 */
                    211:                if (u & 0x1)
                    212:                        u += s; /* Make largebase+u odd, and u even */
                    213:
                    214:                /* Mark all multiples of 2*s */
                    215:                for (u /= 2; u < largebits; u += s)
                    216:                        BIT_SET(LargeSieve, u);
                    217:        }
                    218:
                    219:        /* r = p mod s */
                    220:        r = (2 * r + 1) % s;
                    221:        if (r == 0)
                    222:                u = 0; /* s divides p exactly */
                    223:        else
                    224:                u = s - r; /* p+u is first entry divisible by s */
                    225:
                    226:        if (u < largebits * 4) {
                    227:                /*
                    228:                 * The sieve omits p's divisible by 4, so ensure that
                    229:                 * largebase+u is not. Then, step through the sieve in
                    230:                 * increments of 4*s
                    231:                 */
                    232:                while (u & 0x3) {
                    233:                        if (SMALL_MAXIMUM - u < s)
                    234:                                return;
                    235:                        u += s;
                    236:                }
                    237:
                    238:                /* Mark all multiples of 4*s */
                    239:                for (u /= 4; u < largebits; u += s)
                    240:                        BIT_SET(LargeSieve, u);
                    241:        }
                    242: }
                    243:
                    244: /*
1.6       djm       245:  * list candidates for Sophie-Germain primes (where q = (p-1)/2)
1.1       djm       246:  * to standard output.
                    247:  * The list is checked against small known primes (less than 2**30).
                    248:  */
                    249: int
1.11      avsm      250: gen_candidates(FILE *out, u_int32_t memory, u_int32_t power, BIGNUM *start)
1.1       djm       251: {
                    252:        BIGNUM *q;
                    253:        u_int32_t j, r, s, t;
                    254:        u_int32_t smallwords = TINY_NUMBER >> 6;
                    255:        u_int32_t tinywords = TINY_NUMBER >> 6;
                    256:        time_t time_start, time_stop;
1.11      avsm      257:        u_int32_t i;
                    258:        int ret = 0;
1.1       djm       259:
                    260:        largememory = memory;
                    261:
1.7       djm       262:        if (memory != 0 &&
1.12      djm       263:            (memory < LARGE_MINIMUM || memory > LARGE_MAXIMUM)) {
1.7       djm       264:                error("Invalid memory amount (min %ld, max %ld)",
                    265:                    LARGE_MINIMUM, LARGE_MAXIMUM);
                    266:                return (-1);
                    267:        }
                    268:
1.1       djm       269:        /*
1.2       djm       270:         * Set power to the length in bits of the prime to be generated.
                    271:         * This is changed to 1 less than the desired safe prime moduli p.
                    272:         */
1.1       djm       273:        if (power > TEST_MAXIMUM) {
                    274:                error("Too many bits: %u > %lu", power, TEST_MAXIMUM);
                    275:                return (-1);
                    276:        } else if (power < TEST_MINIMUM) {
                    277:                error("Too few bits: %u < %u", power, TEST_MINIMUM);
                    278:                return (-1);
                    279:        }
                    280:        power--; /* decrement before squaring */
                    281:
                    282:        /*
1.2       djm       283:         * The density of ordinary primes is on the order of 1/bits, so the
                    284:         * density of safe primes should be about (1/bits)**2. Set test range
                    285:         * to something well above bits**2 to be reasonably sure (but not
                    286:         * guaranteed) of catching at least one safe prime.
1.1       djm       287:         */
                    288:        largewords = ((power * power) >> (SHIFT_WORD - TEST_POWER));
                    289:
                    290:        /*
1.2       djm       291:         * Need idea of how much memory is available. We don't have to use all
                    292:         * of it.
1.1       djm       293:         */
                    294:        if (largememory > LARGE_MAXIMUM) {
                    295:                logit("Limited memory: %u MB; limit %lu MB",
                    296:                    largememory, LARGE_MAXIMUM);
                    297:                largememory = LARGE_MAXIMUM;
                    298:        }
                    299:
                    300:        if (largewords <= (largememory << SHIFT_MEGAWORD)) {
                    301:                logit("Increased memory: %u MB; need %u bytes",
                    302:                    largememory, (largewords << SHIFT_BYTE));
                    303:                largewords = (largememory << SHIFT_MEGAWORD);
                    304:        } else if (largememory > 0) {
                    305:                logit("Decreased memory: %u MB; want %u bytes",
                    306:                    largememory, (largewords << SHIFT_BYTE));
                    307:                largewords = (largememory << SHIFT_MEGAWORD);
                    308:        }
                    309:
1.13      djm       310:        TinySieve = xcalloc(tinywords, sizeof(u_int32_t));
1.1       djm       311:        tinybits = tinywords << SHIFT_WORD;
                    312:
1.13      djm       313:        SmallSieve = xcalloc(smallwords, sizeof(u_int32_t));
1.1       djm       314:        smallbits = smallwords << SHIFT_WORD;
                    315:
                    316:        /*
                    317:         * dynamically determine available memory
                    318:         */
                    319:        while ((LargeSieve = calloc(largewords, sizeof(u_int32_t))) == NULL)
                    320:                largewords -= (1L << (SHIFT_MEGAWORD - 2)); /* 1/4 MB chunks */
                    321:
                    322:        largebits = largewords << SHIFT_WORD;
                    323:        largenumbers = largebits * 2;   /* even numbers excluded */
                    324:
                    325:        /* validation check: count the number of primes tried */
                    326:        largetries = 0;
                    327:        q = BN_new();
                    328:
                    329:        /*
1.2       djm       330:         * Generate random starting point for subprime search, or use
                    331:         * specified parameter.
1.1       djm       332:         */
                    333:        largebase = BN_new();
                    334:        if (start == NULL)
                    335:                BN_rand(largebase, power, 1, 1);
                    336:        else
                    337:                BN_copy(largebase, start);
                    338:
                    339:        /* ensure odd */
                    340:        BN_set_bit(largebase, 0);
                    341:
                    342:        time(&time_start);
                    343:
1.2       djm       344:        logit("%.24s Sieve next %u plus %u-bit", ctime(&time_start),
1.1       djm       345:            largenumbers, power);
                    346:        debug2("start point: 0x%s", BN_bn2hex(largebase));
                    347:
                    348:        /*
1.2       djm       349:         * TinySieve
                    350:         */
1.1       djm       351:        for (i = 0; i < tinybits; i++) {
                    352:                if (BIT_TEST(TinySieve, i))
                    353:                        continue; /* 2*i+3 is composite */
                    354:
                    355:                /* The next tiny prime */
                    356:                t = 2 * i + 3;
                    357:
                    358:                /* Mark all multiples of t */
                    359:                for (j = i + t; j < tinybits; j += t)
                    360:                        BIT_SET(TinySieve, j);
                    361:
                    362:                sieve_large(t);
                    363:        }
                    364:
                    365:        /*
1.2       djm       366:         * Start the small block search at the next possible prime. To avoid
                    367:         * fencepost errors, the last pass is skipped.
                    368:         */
1.1       djm       369:        for (smallbase = TINY_NUMBER + 3;
1.12      djm       370:            smallbase < (SMALL_MAXIMUM - TINY_NUMBER);
                    371:            smallbase += TINY_NUMBER) {
1.1       djm       372:                for (i = 0; i < tinybits; i++) {
                    373:                        if (BIT_TEST(TinySieve, i))
                    374:                                continue; /* 2*i+3 is composite */
                    375:
                    376:                        /* The next tiny prime */
                    377:                        t = 2 * i + 3;
                    378:                        r = smallbase % t;
                    379:
                    380:                        if (r == 0) {
                    381:                                s = 0; /* t divides into smallbase exactly */
                    382:                        } else {
                    383:                                /* smallbase+s is first entry divisible by t */
                    384:                                s = t - r;
                    385:                        }
                    386:
                    387:                        /*
                    388:                         * The sieve omits even numbers, so ensure that
                    389:                         * smallbase+s is odd. Then, step through the sieve
                    390:                         * in increments of 2*t
                    391:                         */
                    392:                        if (s & 1)
                    393:                                s += t; /* Make smallbase+s odd, and s even */
                    394:
                    395:                        /* Mark all multiples of 2*t */
                    396:                        for (s /= 2; s < smallbits; s += t)
                    397:                                BIT_SET(SmallSieve, s);
                    398:                }
                    399:
                    400:                /*
1.2       djm       401:                 * SmallSieve
                    402:                 */
1.1       djm       403:                for (i = 0; i < smallbits; i++) {
                    404:                        if (BIT_TEST(SmallSieve, i))
                    405:                                continue; /* 2*i+smallbase is composite */
                    406:
                    407:                        /* The next small prime */
                    408:                        sieve_large((2 * i) + smallbase);
                    409:                }
                    410:
                    411:                memset(SmallSieve, 0, smallwords << SHIFT_BYTE);
                    412:        }
                    413:
                    414:        time(&time_stop);
                    415:
                    416:        logit("%.24s Sieved with %u small primes in %ld seconds",
                    417:            ctime(&time_stop), largetries, (long) (time_stop - time_start));
                    418:
                    419:        for (j = r = 0; j < largebits; j++) {
                    420:                if (BIT_TEST(LargeSieve, j))
                    421:                        continue; /* Definitely composite, skip */
                    422:
                    423:                debug2("test q = largebase+%u", 2 * j);
                    424:                BN_set_word(q, 2 * j);
                    425:                BN_add(q, q, largebase);
1.6       djm       426:                if (qfileout(out, QTYPE_SOPHIE_GERMAIN, QTEST_SIEVE,
1.1       djm       427:                    largetries, (power - 1) /* MSB */, (0), q) == -1) {
                    428:                        ret = -1;
                    429:                        break;
                    430:                }
                    431:
                    432:                r++; /* count q */
                    433:        }
                    434:
                    435:        time(&time_stop);
                    436:
                    437:        xfree(LargeSieve);
                    438:        xfree(SmallSieve);
                    439:        xfree(TinySieve);
                    440:
                    441:        logit("%.24s Found %u candidates", ctime(&time_stop), r);
                    442:
                    443:        return (ret);
                    444: }
                    445:
                    446: /*
                    447:  * perform a Miller-Rabin primality test
                    448:  * on the list of candidates
                    449:  * (checking both q and p)
                    450:  * The result is a list of so-call "safe" primes
                    451:  */
                    452: int
1.7       djm       453: prime_test(FILE *in, FILE *out, u_int32_t trials, u_int32_t generator_wanted)
1.1       djm       454: {
                    455:        BIGNUM *q, *p, *a;
                    456:        BN_CTX *ctx;
                    457:        char *cp, *lp;
                    458:        u_int32_t count_in = 0, count_out = 0, count_possible = 0;
                    459:        u_int32_t generator_known, in_tests, in_tries, in_type, in_size;
                    460:        time_t time_start, time_stop;
                    461:        int res;
1.7       djm       462:
                    463:        if (trials < TRIAL_MINIMUM) {
                    464:                error("Minimum primality trials is %d", TRIAL_MINIMUM);
                    465:                return (-1);
                    466:        }
1.1       djm       467:
                    468:        time(&time_start);
                    469:
                    470:        p = BN_new();
                    471:        q = BN_new();
                    472:        ctx = BN_CTX_new();
                    473:
                    474:        debug2("%.24s Final %u Miller-Rabin trials (%x generator)",
                    475:            ctime(&time_start), trials, generator_wanted);
                    476:
                    477:        res = 0;
                    478:        lp = xmalloc(QLINESIZE + 1);
                    479:        while (fgets(lp, QLINESIZE, in) != NULL) {
                    480:                int ll = strlen(lp);
                    481:
                    482:                count_in++;
                    483:                if (ll < 14 || *lp == '!' || *lp == '#') {
                    484:                        debug2("%10u: comment or short line", count_in);
                    485:                        continue;
                    486:                }
                    487:
                    488:                /* XXX - fragile parser */
                    489:                /* time */
                    490:                cp = &lp[14];   /* (skip) */
                    491:
                    492:                /* type */
                    493:                in_type = strtoul(cp, &cp, 10);
                    494:
                    495:                /* tests */
                    496:                in_tests = strtoul(cp, &cp, 10);
                    497:
                    498:                if (in_tests & QTEST_COMPOSITE) {
                    499:                        debug2("%10u: known composite", count_in);
                    500:                        continue;
                    501:                }
1.5       djm       502:
1.1       djm       503:                /* tries */
                    504:                in_tries = strtoul(cp, &cp, 10);
                    505:
                    506:                /* size (most significant bit) */
                    507:                in_size = strtoul(cp, &cp, 10);
                    508:
                    509:                /* generator (hex) */
                    510:                generator_known = strtoul(cp, &cp, 16);
                    511:
                    512:                /* Skip white space */
                    513:                cp += strspn(cp, " ");
                    514:
                    515:                /* modulus (hex) */
                    516:                switch (in_type) {
1.6       djm       517:                case QTYPE_SOPHIE_GERMAIN:
                    518:                        debug2("%10u: (%u) Sophie-Germain", count_in, in_type);
1.1       djm       519:                        a = q;
                    520:                        BN_hex2bn(&a, cp);
                    521:                        /* p = 2*q + 1 */
                    522:                        BN_lshift(p, q, 1);
                    523:                        BN_add_word(p, 1);
                    524:                        in_size += 1;
                    525:                        generator_known = 0;
                    526:                        break;
1.5       djm       527:                case QTYPE_UNSTRUCTURED:
                    528:                case QTYPE_SAFE:
1.10      dtucker   529:                case QTYPE_SCHNORR:
1.5       djm       530:                case QTYPE_STRONG:
                    531:                case QTYPE_UNKNOWN:
1.1       djm       532:                        debug2("%10u: (%u)", count_in, in_type);
                    533:                        a = p;
                    534:                        BN_hex2bn(&a, cp);
                    535:                        /* q = (p-1) / 2 */
                    536:                        BN_rshift(q, p, 1);
                    537:                        break;
1.5       djm       538:                default:
                    539:                        debug2("Unknown prime type");
                    540:                        break;
1.1       djm       541:                }
                    542:
                    543:                /*
                    544:                 * due to earlier inconsistencies in interpretation, check
                    545:                 * the proposed bit size.
                    546:                 */
1.11      avsm      547:                if ((u_int32_t)BN_num_bits(p) != (in_size + 1)) {
1.1       djm       548:                        debug2("%10u: bit size %u mismatch", count_in, in_size);
                    549:                        continue;
                    550:                }
                    551:                if (in_size < QSIZE_MINIMUM) {
                    552:                        debug2("%10u: bit size %u too short", count_in, in_size);
                    553:                        continue;
                    554:                }
                    555:
                    556:                if (in_tests & QTEST_MILLER_RABIN)
                    557:                        in_tries += trials;
                    558:                else
                    559:                        in_tries = trials;
1.5       djm       560:
1.1       djm       561:                /*
                    562:                 * guess unknown generator
                    563:                 */
                    564:                if (generator_known == 0) {
                    565:                        if (BN_mod_word(p, 24) == 11)
                    566:                                generator_known = 2;
                    567:                        else if (BN_mod_word(p, 12) == 5)
                    568:                                generator_known = 3;
                    569:                        else {
                    570:                                u_int32_t r = BN_mod_word(p, 10);
                    571:
1.5       djm       572:                                if (r == 3 || r == 7)
1.1       djm       573:                                        generator_known = 5;
                    574:                        }
                    575:                }
                    576:                /*
                    577:                 * skip tests when desired generator doesn't match
                    578:                 */
                    579:                if (generator_wanted > 0 &&
                    580:                    generator_wanted != generator_known) {
                    581:                        debug2("%10u: generator %d != %d",
                    582:                            count_in, generator_known, generator_wanted);
1.4       dtucker   583:                        continue;
                    584:                }
                    585:
                    586:                /*
                    587:                 * Primes with no known generator are useless for DH, so
                    588:                 * skip those.
                    589:                 */
                    590:                if (generator_known == 0) {
                    591:                        debug2("%10u: no known generator", count_in);
1.1       djm       592:                        continue;
                    593:                }
                    594:
                    595:                count_possible++;
                    596:
                    597:                /*
1.2       djm       598:                 * The (1/4)^N performance bound on Miller-Rabin is
                    599:                 * extremely pessimistic, so don't spend a lot of time
                    600:                 * really verifying that q is prime until after we know
                    601:                 * that p is also prime. A single pass will weed out the
1.1       djm       602:                 * vast majority of composite q's.
                    603:                 */
                    604:                if (BN_is_prime(q, 1, NULL, ctx, NULL) <= 0) {
1.5       djm       605:                        debug("%10u: q failed first possible prime test",
1.1       djm       606:                            count_in);
                    607:                        continue;
                    608:                }
1.2       djm       609:
1.1       djm       610:                /*
1.2       djm       611:                 * q is possibly prime, so go ahead and really make sure
                    612:                 * that p is prime. If it is, then we can go back and do
                    613:                 * the same for q. If p is composite, chances are that
1.1       djm       614:                 * will show up on the first Rabin-Miller iteration so it
                    615:                 * doesn't hurt to specify a high iteration count.
                    616:                 */
                    617:                if (!BN_is_prime(p, trials, NULL, ctx, NULL)) {
1.5       djm       618:                        debug("%10u: p is not prime", count_in);
1.1       djm       619:                        continue;
                    620:                }
                    621:                debug("%10u: p is almost certainly prime", count_in);
                    622:
                    623:                /* recheck q more rigorously */
                    624:                if (!BN_is_prime(q, trials - 1, NULL, ctx, NULL)) {
                    625:                        debug("%10u: q is not prime", count_in);
                    626:                        continue;
                    627:                }
                    628:                debug("%10u: q is almost certainly prime", count_in);
                    629:
1.2       djm       630:                if (qfileout(out, QTYPE_SAFE, (in_tests | QTEST_MILLER_RABIN),
1.1       djm       631:                    in_tries, in_size, generator_known, p)) {
                    632:                        res = -1;
                    633:                        break;
                    634:                }
                    635:
                    636:                count_out++;
                    637:        }
                    638:
                    639:        time(&time_stop);
                    640:        xfree(lp);
                    641:        BN_free(p);
                    642:        BN_free(q);
                    643:        BN_CTX_free(ctx);
                    644:
                    645:        logit("%.24s Found %u safe primes of %u candidates in %ld seconds",
1.2       djm       646:            ctime(&time_stop), count_out, count_possible,
1.1       djm       647:            (long) (time_stop - time_start));
                    648:
                    649:        return (res);
                    650: }