/src/openssl/crypto/dsa/dsa_gen.c

Source (jump to first uncovered line)
/* crypto/dsa/dsa_gen.c */
/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
 * All rights reserved.
 *
 * This package is an SSL implementation written
 * by Eric Young (eay@cryptsoft.com).
 * The implementation was written so as to conform with Netscapes SSL.
 *
 * This library is free for commercial and non-commercial use as long as
 * the following conditions are aheared to.  The following conditions
 * apply to all code found in this distribution, be it the RC4, RSA,
 * lhash, DES, etc., code; not just the SSL code.  The SSL documentation
 * included with this distribution is covered by the same copyright terms
 * except that the holder is Tim Hudson (tjh@cryptsoft.com).
 *
 * Copyright remains Eric Young's, and as such any Copyright notices in
 * the code are not to be removed.
 * If this package is used in a product, Eric Young should be given attribution
 * as the author of the parts of the library used.
 * This can be in the form of a textual message at program startup or
 * in documentation (online or textual) provided with the package.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *    "This product includes cryptographic software written by
 *     Eric Young (eay@cryptsoft.com)"
 *    The word 'cryptographic' can be left out if the rouines from the library
 *    being used are not cryptographic related :-).
 * 4. If you include any Windows specific code (or a derivative thereof) from
 *    the apps directory (application code) you must include an acknowledgement:
 *    "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
 *
 * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 * The licence and distribution terms for any publically available version or
 * derivative of this code cannot be changed.  i.e. this code cannot simply be
 * copied and put under another distribution licence
 * [including the GNU Public Licence.]
 */

#undef GENUINE_DSA

#ifdef GENUINE_DSA
/*
 * Parameter generation follows the original release of FIPS PUB 186,
 * Appendix 2.2 (i.e. use SHA as defined in FIPS PUB 180)
 */
# define HASH    EVP_sha()
#else
/*
 * Parameter generation follows the updated Appendix 2.2 for FIPS PUB 186,
 * also Appendix 2.2 of FIPS PUB 186-1 (i.e. use SHA as defined in FIPS PUB
 * 180-1)
 */
# define HASH    EVP_sha1()
#endif

#include <openssl/opensslconf.h> /* To see if OPENSSL_NO_SHA is defined */

#ifndef OPENSSL_NO_SHA

# include <stdio.h>
# include "cryptlib.h"
# include <openssl/evp.h>
# include <openssl/bn.h>
# include <openssl/rand.h>
# include <openssl/sha.h>
# include "dsa_locl.h"

# ifdef OPENSSL_FIPS
/* Workaround bug in prototype */
#  define fips_dsa_builtin_paramgen2 fips_dsa_paramgen_bad
#  include <openssl/fips.h>
# endif

int DSA_generate_parameters_ex(DSA *ret, int bits,
                               const unsigned char *seed_in, int seed_len,
                               int *counter_ret, unsigned long *h_ret,
                               BN_GENCB *cb)
{
# ifdef OPENSSL_FIPS
    if (FIPS_mode() && !(ret->meth->flags & DSA_FLAG_FIPS_METHOD)
        && !(ret->flags & DSA_FLAG_NON_FIPS_ALLOW)) {
        DSAerr(DSA_F_DSA_GENERATE_PARAMETERS_EX, DSA_R_NON_FIPS_DSA_METHOD);
        return 0;
    }
# endif
    if (ret->meth->dsa_paramgen)
        return ret->meth->dsa_paramgen(ret, bits, seed_in, seed_len,
                                       counter_ret, h_ret, cb);
# ifdef OPENSSL_FIPS
    else if (FIPS_mode()) {
        return FIPS_dsa_generate_parameters_ex(ret, bits,
                                               seed_in, seed_len,
                                               counter_ret, h_ret, cb);
    }
# endif
    else {
        const EVP_MD *evpmd = bits >= 2048 ? EVP_sha256() : EVP_sha1();
        size_t qbits = EVP_MD_size(evpmd) * 8;

        return dsa_builtin_paramgen(ret, bits, qbits, evpmd,
                                    seed_in, seed_len, NULL, counter_ret,
                                    h_ret, cb);
    }
}

int dsa_builtin_paramgen(DSA *ret, size_t bits, size_t qbits,
                         const EVP_MD *evpmd, const unsigned char *seed_in,
                         size_t seed_len, unsigned char *seed_out,
                         int *counter_ret, unsigned long *h_ret, BN_GENCB *cb)
{
    int ok = 0;
    unsigned char seed[SHA256_DIGEST_LENGTH];
    unsigned char md[SHA256_DIGEST_LENGTH];
    unsigned char buf[SHA256_DIGEST_LENGTH], buf2[SHA256_DIGEST_LENGTH];
    BIGNUM *r0, *W, *X, *c, *test;
    BIGNUM *g = NULL, *q = NULL, *p = NULL;
    BN_MONT_CTX *mont = NULL;
    int i, k, n = 0, m = 0, qsize = qbits >> 3;
    int counter = 0;
    int r = 0;
    BN_CTX *ctx = NULL;
    unsigned int h = 2;

    if (qsize != SHA_DIGEST_LENGTH && qsize != SHA224_DIGEST_LENGTH &&
        qsize != SHA256_DIGEST_LENGTH)
        /* invalid q size */
        return 0;

    if (evpmd == NULL)
        /* use SHA1 as default */
        evpmd = EVP_sha1();

    if (bits < 512)
        bits = 512;

    bits = (bits + 63) / 64 * 64;

    /*
     * NB: seed_len == 0 is special case: copy generated seed to seed_in if
     * it is not NULL.
     */
    if (seed_len && (seed_len < (size_t)qsize))
        seed_in = NULL;         /* seed buffer too small -- ignore */
    if (seed_len > (size_t)qsize)
        seed_len = qsize;       /* App. 2.2 of FIPS PUB 186 allows larger
                                 * SEED, but our internal buffers are
                                 * restricted to 160 bits */
    if (seed_in != NULL)
        memcpy(seed, seed_in, seed_len);

    if ((mont = BN_MONT_CTX_new()) == NULL)
        goto err;

    if ((ctx = BN_CTX_new()) == NULL)
        goto err;

    BN_CTX_start(ctx);

    r0 = BN_CTX_get(ctx);
    g = BN_CTX_get(ctx);
    W = BN_CTX_get(ctx);
    q = BN_CTX_get(ctx);
    X = BN_CTX_get(ctx);
    c = BN_CTX_get(ctx);
    p = BN_CTX_get(ctx);
    test = BN_CTX_get(ctx);

    if (test == NULL)
        goto err;

    if (!BN_lshift(test, BN_value_one(), bits - 1))
        goto err;

    for (;;) {
        for (;;) {              /* find q */
            int seed_is_random;

            /* step 1 */
            if (!BN_GENCB_call(cb, 0, m++))
                goto err;

            if (!seed_len || !seed_in) {
                if (RAND_bytes(seed, qsize) <= 0)
                    goto err;
                seed_is_random = 1;
            } else {
                seed_is_random = 0;
                seed_len = 0;   /* use random seed if 'seed_in' turns out to
                                 * be bad */
            }
            memcpy(buf, seed, qsize);
            memcpy(buf2, seed, qsize);
            /* precompute "SEED + 1" for step 7: */
            for (i = qsize - 1; i >= 0; i--) {
                buf[i]++;
                if (buf[i] != 0)
                    break;
            }

            /* step 2 */
            if (!EVP_Digest(seed, qsize, md, NULL, evpmd, NULL))
                goto err;
            if (!EVP_Digest(buf, qsize, buf2, NULL, evpmd, NULL))
                goto err;
            for (i = 0; i < qsize; i++)
                md[i] ^= buf2[i];

            /* step 3 */
            md[0] |= 0x80;
            md[qsize - 1] |= 0x01;
            if (!BN_bin2bn(md, qsize, q))
                goto err;

            /* step 4 */
            r = BN_is_prime_fasttest_ex(q, DSS_prime_checks, ctx,
                                        seed_is_random, cb);
            if (r > 0)
                break;
            if (r != 0)
                goto err;

            /* do a callback call */
            /* step 5 */
        }

        if (!BN_GENCB_call(cb, 2, 0))
            goto err;
        if (!BN_GENCB_call(cb, 3, 0))
            goto err;

        /* step 6 */
        counter = 0;
        /* "offset = 2" */

        n = (bits - 1) / 160;

        for (;;) {
            if ((counter != 0) && !BN_GENCB_call(cb, 0, counter))
                goto err;

            /* step 7 */
            BN_zero(W);
            /* now 'buf' contains "SEED + offset - 1" */
            for (k = 0; k <= n; k++) {
                /*
                 * obtain "SEED + offset + k" by incrementing:
                 */
                for (i = qsize - 1; i >= 0; i--) {
                    buf[i]++;
                    if (buf[i] != 0)
                        break;
                }

                if (!EVP_Digest(buf, qsize, md, NULL, evpmd, NULL))
                    goto err;

                /* step 8 */
                if (!BN_bin2bn(md, qsize, r0))
                    goto err;
                if (!BN_lshift(r0, r0, (qsize << 3) * k))
                    goto err;
                if (!BN_add(W, W, r0))
                    goto err;
            }

            /* more of step 8 */
            if (!BN_mask_bits(W, bits - 1))
                goto err;
            if (!BN_copy(X, W))
                goto err;
            if (!BN_add(X, X, test))
                goto err;

            /* step 9 */
            if (!BN_lshift1(r0, q))
                goto err;
            if (!BN_mod(c, X, r0, ctx))
                goto err;
            if (!BN_sub(r0, c, BN_value_one()))
                goto err;
            if (!BN_sub(p, X, r0))
                goto err;

            /* step 10 */
            if (BN_cmp(p, test) >= 0) {
                /* step 11 */
                r = BN_is_prime_fasttest_ex(p, DSS_prime_checks, ctx, 1, cb);
                if (r > 0)
                    goto end;   /* found it */
                if (r != 0)
                    goto err;
            }

            /* step 13 */
            counter++;
            /* "offset = offset + n + 1" */

            /* step 14 */
            if (counter >= 4096)
                break;
        }
    }
 end:
    if (!BN_GENCB_call(cb, 2, 1))
        goto err;

    /* We now need to generate g */
    /* Set r0=(p-1)/q */
    if (!BN_sub(test, p, BN_value_one()))
        goto err;
    if (!BN_div(r0, NULL, test, q, ctx))
        goto err;

    if (!BN_set_word(test, h))
        goto err;
    if (!BN_MONT_CTX_set(mont, p, ctx))
        goto err;

    for (;;) {
        /* g=test^r0%p */
        if (!BN_mod_exp_mont(g, test, r0, p, ctx, mont))
            goto err;
        if (!BN_is_one(g))
            break;
        if (!BN_add(test, test, BN_value_one()))
            goto err;
        h++;
    }

    if (!BN_GENCB_call(cb, 3, 1))
        goto err;

    ok = 1;
 err:
    if (ok) {
        if (ret->p)
            BN_free(ret->p);
        if (ret->q)
            BN_free(ret->q);
        if (ret->g)
            BN_free(ret->g);
        ret->p = BN_dup(p);
        ret->q = BN_dup(q);
        ret->g = BN_dup(g);
        if (ret->p == NULL || ret->q == NULL || ret->g == NULL) {
            ok = 0;
            goto err;
        }
        if (counter_ret != NULL)
            *counter_ret = counter;
        if (h_ret != NULL)
            *h_ret = h;
        if (seed_out)
            memcpy(seed_out, seed, qsize);
    }
    if (ctx) {
        BN_CTX_end(ctx);
        BN_CTX_free(ctx);
    }
    if (mont != NULL)
        BN_MONT_CTX_free(mont);
    return ok;
}

# ifdef OPENSSL_FIPS
#  undef fips_dsa_builtin_paramgen2
extern int fips_dsa_builtin_paramgen2(DSA *ret, size_t L, size_t N,
                                      const EVP_MD *evpmd,
                                      const unsigned char *seed_in,
                                      size_t seed_len, int idx,
                                      unsigned char *seed_out,
                                      int *counter_ret, unsigned long *h_ret,
                                      BN_GENCB *cb);
# endif

/*
 * This is a parameter generation algorithm for the DSA2 algorithm as
 * described in FIPS 186-3.
 */

int dsa_builtin_paramgen2(DSA *ret, size_t L, size_t N,
                          const EVP_MD *evpmd, const unsigned char *seed_in,
                          size_t seed_len, int idx, unsigned char *seed_out,
                          int *counter_ret, unsigned long *h_ret,
                          BN_GENCB *cb)
{
    int ok = -1;
    unsigned char *seed = NULL, *seed_tmp = NULL;
    unsigned char md[EVP_MAX_MD_SIZE];
    int mdsize;
    BIGNUM *r0, *W, *X, *c, *test;
    BIGNUM *g = NULL, *q = NULL, *p = NULL;
    BN_MONT_CTX *mont = NULL;
    int i, k, n = 0, m = 0, qsize = N >> 3;
    int counter = 0;
    int r = 0;
    BN_CTX *ctx = NULL;
    EVP_MD_CTX mctx;
    unsigned int h = 2;

# ifdef OPENSSL_FIPS

    if (FIPS_mode())
        return fips_dsa_builtin_paramgen2(ret, L, N, evpmd,
                                          seed_in, seed_len, idx,
                                          seed_out, counter_ret, h_ret, cb);
# endif

    EVP_MD_CTX_init(&mctx);

    if (evpmd == NULL) {
        if (N == 160)
            evpmd = EVP_sha1();
        else if (N == 224)
            evpmd = EVP_sha224();
        else
            evpmd = EVP_sha256();
    }

    mdsize = EVP_MD_size(evpmd);
    /* If unverificable g generation only don't need seed */
    if (!ret->p || !ret->q || idx >= 0) {
        if (seed_len == 0)
            seed_len = mdsize;

        seed = OPENSSL_malloc(seed_len);

        if (seed_out)
            seed_tmp = seed_out;
        else
            seed_tmp = OPENSSL_malloc(seed_len);

        if (!seed || !seed_tmp)
            goto err;

        if (seed_in)
            memcpy(seed, seed_in, seed_len);

    }

    if ((ctx = BN_CTX_new()) == NULL)
        goto err;

    if ((mont = BN_MONT_CTX_new()) == NULL)
        goto err;

    BN_CTX_start(ctx);
    r0 = BN_CTX_get(ctx);
    g = BN_CTX_get(ctx);
    W = BN_CTX_get(ctx);
    X = BN_CTX_get(ctx);
    c = BN_CTX_get(ctx);
    test = BN_CTX_get(ctx);

    /* if p, q already supplied generate g only */
    if (ret->p && ret->q) {
        p = ret->p;
        q = ret->q;
        if (idx >= 0)
            memcpy(seed_tmp, seed, seed_len);
        goto g_only;
    } else {
        p = BN_CTX_get(ctx);
        q = BN_CTX_get(ctx);
        if (q == NULL)
            goto err;
    }

    if (!BN_lshift(test, BN_value_one(), L - 1))
        goto err;
    for (;;) {
        for (;;) {              /* find q */
            unsigned char *pmd;
            /* step 1 */
            if (!BN_GENCB_call(cb, 0, m++))
                goto err;

            if (!seed_in) {
                if (RAND_bytes(seed, seed_len) <= 0)
                    goto err;
            }
            /* step 2 */
            if (!EVP_Digest(seed, seed_len, md, NULL, evpmd, NULL))
                goto err;
            /* Take least significant bits of md */
            if (mdsize > qsize)
                pmd = md + mdsize - qsize;
            else
                pmd = md;

            if (mdsize < qsize)
                memset(md + mdsize, 0, qsize - mdsize);

            /* step 3 */
            pmd[0] |= 0x80;
            pmd[qsize - 1] |= 0x01;
            if (!BN_bin2bn(pmd, qsize, q))
                goto err;

            /* step 4 */
            r = BN_is_prime_fasttest_ex(q, DSS_prime_checks, ctx,
                                        seed_in ? 1 : 0, cb);
            if (r > 0)
                break;
            if (r != 0)
                goto err;
            /* Provided seed didn't produce a prime: error */
            if (seed_in) {
                ok = 0;
                DSAerr(DSA_F_DSA_BUILTIN_PARAMGEN2, DSA_R_Q_NOT_PRIME);
                goto err;
            }

            /* do a callback call */
            /* step 5 */
        }
        /* Copy seed to seed_out before we mess with it */
        if (seed_out)
            memcpy(seed_out, seed, seed_len);

        if (!BN_GENCB_call(cb, 2, 0))
            goto err;
        if (!BN_GENCB_call(cb, 3, 0))
            goto err;

        /* step 6 */
        counter = 0;
        /* "offset = 1" */

        n = (L - 1) / (mdsize << 3);

        for (;;) {
            if ((counter != 0) && !BN_GENCB_call(cb, 0, counter))
                goto err;

            /* step 7 */
            BN_zero(W);
            /* now 'buf' contains "SEED + offset - 1" */
            for (k = 0; k <= n; k++) {
                /*
                 * obtain "SEED + offset + k" by incrementing:
                 */
                for (i = seed_len - 1; i >= 0; i--) {
                    seed[i]++;
                    if (seed[i] != 0)
                        break;
                }

                if (!EVP_Digest(seed, seed_len, md, NULL, evpmd, NULL))
                    goto err;

                /* step 8 */
                if (!BN_bin2bn(md, mdsize, r0))
                    goto err;
                if (!BN_lshift(r0, r0, (mdsize << 3) * k))
                    goto err;
                if (!BN_add(W, W, r0))
                    goto err;
            }

            /* more of step 8 */
            if (!BN_mask_bits(W, L - 1))
                goto err;
            if (!BN_copy(X, W))
                goto err;
            if (!BN_add(X, X, test))
                goto err;

            /* step 9 */
            if (!BN_lshift1(r0, q))
                goto err;
            if (!BN_mod(c, X, r0, ctx))
                goto err;
            if (!BN_sub(r0, c, BN_value_one()))
                goto err;
            if (!BN_sub(p, X, r0))
                goto err;

            /* step 10 */
            if (BN_cmp(p, test) >= 0) {
                /* step 11 */
                r = BN_is_prime_fasttest_ex(p, DSS_prime_checks, ctx, 1, cb);
                if (r > 0)
                    goto end;   /* found it */
                if (r != 0)
                    goto err;
            }

            /* step 13 */
            counter++;
            /* "offset = offset + n + 1" */

            /* step 14 */
            if (counter >= (int)(4 * L))
                break;
        }
        if (seed_in) {
            ok = 0;
            DSAerr(DSA_F_DSA_BUILTIN_PARAMGEN2, DSA_R_INVALID_PARAMETERS);
            goto err;
        }
    }
 end:
    if (!BN_GENCB_call(cb, 2, 1))
        goto err;

 g_only:

    /* We now need to generate g */
    /* Set r0=(p-1)/q */
    if (!BN_sub(test, p, BN_value_one()))
        goto err;
    if (!BN_div(r0, NULL, test, q, ctx))
        goto err;

    if (idx < 0) {
        if (!BN_set_word(test, h))
            goto err;
    } else
        h = 1;
    if (!BN_MONT_CTX_set(mont, p, ctx))
        goto err;

    for (;;) {
        static const unsigned char ggen[4] = { 0x67, 0x67, 0x65, 0x6e };
        if (idx >= 0) {
            md[0] = idx & 0xff;
            md[1] = (h >> 8) & 0xff;
            md[2] = h & 0xff;
            if (!EVP_DigestInit_ex(&mctx, evpmd, NULL))
                goto err;
            if (!EVP_DigestUpdate(&mctx, seed_tmp, seed_len))
                goto err;
            if (!EVP_DigestUpdate(&mctx, ggen, sizeof(ggen)))
                goto err;
            if (!EVP_DigestUpdate(&mctx, md, 3))
                goto err;
            if (!EVP_DigestFinal_ex(&mctx, md, NULL))
                goto err;
            if (!BN_bin2bn(md, mdsize, test))
                goto err;
        }
        /* g=test^r0%p */
        if (!BN_mod_exp_mont(g, test, r0, p, ctx, mont))
            goto err;
        if (!BN_is_one(g))
            break;
        if (idx < 0 && !BN_add(test, test, BN_value_one()))
            goto err;
        h++;
        if (idx >= 0 && h > 0xffff)
            goto err;
    }

    if (!BN_GENCB_call(cb, 3, 1))
        goto err;

    ok = 1;
 err:
    if (ok == 1) {
        if (p != ret->p) {
            if (ret->p)
                BN_free(ret->p);
            ret->p = BN_dup(p);
        }
        if (q != ret->q) {
            if (ret->q)
                BN_free(ret->q);
            ret->q = BN_dup(q);
        }
        if (ret->g)
            BN_free(ret->g);
        ret->g = BN_dup(g);
        if (ret->p == NULL || ret->q == NULL || ret->g == NULL) {
            ok = -1;
            goto err;
        }
        if (counter_ret != NULL)
            *counter_ret = counter;
        if (h_ret != NULL)
            *h_ret = h;
    }
    if (seed)
        OPENSSL_free(seed);
    if (seed_out != seed_tmp)
        OPENSSL_free(seed_tmp);
    if (ctx) {
        BN_CTX_end(ctx);
        BN_CTX_free(ctx);
    }
    if (mont != NULL)
        BN_MONT_CTX_free(mont);
    EVP_MD_CTX_cleanup(&mctx);
    return ok;
}

int dsa_paramgen_check_g(DSA *dsa)
{
    BN_CTX *ctx;
    BIGNUM *tmp;
    BN_MONT_CTX *mont = NULL;
    int rv = -1;
    ctx = BN_CTX_new();
    if (!ctx)
        return -1;
    BN_CTX_start(ctx);
    if (BN_cmp(dsa->g, BN_value_one()) <= 0)
        return 0;
    if (BN_cmp(dsa->g, dsa->p) >= 0)
        return 0;
    tmp = BN_CTX_get(ctx);
    if (!tmp)
        goto err;
    if ((mont = BN_MONT_CTX_new()) == NULL)
        goto err;
    if (!BN_MONT_CTX_set(mont, dsa->p, ctx))
        goto err;
    /* Work out g^q mod p */
    if (!BN_mod_exp_mont(tmp, dsa->g, dsa->q, dsa->p, ctx, mont))
        goto err;
    if (!BN_cmp(tmp, BN_value_one()))
        rv = 1;
    else
        rv = 0;
 err:
    BN_CTX_end(ctx);
    if (mont)
        BN_MONT_CTX_free(mont);
    BN_CTX_free(ctx);
    return rv;

}
#endif

Coverage Report

Created: 2022-11-30 06:20

Line	Count	Source (jump to first uncovered line)
1		/* crypto/dsa/dsa_gen.c */
2		/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
3		* All rights reserved.
4		*
5		* This package is an SSL implementation written
6		* by Eric Young (eay@cryptsoft.com).
7		* The implementation was written so as to conform with Netscapes SSL.
8		*
9		* This library is free for commercial and non-commercial use as long as
10		* the following conditions are aheared to. The following conditions
11		* apply to all code found in this distribution, be it the RC4, RSA,
12		* lhash, DES, etc., code; not just the SSL code. The SSL documentation
13		* included with this distribution is covered by the same copyright terms
14		* except that the holder is Tim Hudson (tjh@cryptsoft.com).
15		*
16		* Copyright remains Eric Young's, and as such any Copyright notices in
17		* the code are not to be removed.
18		* If this package is used in a product, Eric Young should be given attribution
19		* as the author of the parts of the library used.
20		* This can be in the form of a textual message at program startup or
21		* in documentation (online or textual) provided with the package.
22		*
23		* Redistribution and use in source and binary forms, with or without
24		* modification, are permitted provided that the following conditions
25		* are met:
26		* 1. Redistributions of source code must retain the copyright
27		* notice, this list of conditions and the following disclaimer.
28		* 2. Redistributions in binary form must reproduce the above copyright
29		* notice, this list of conditions and the following disclaimer in the
30		* documentation and/or other materials provided with the distribution.
31		* 3. All advertising materials mentioning features or use of this software
32		* must display the following acknowledgement:
33		* "This product includes cryptographic software written by
34		* Eric Young (eay@cryptsoft.com)"
35		* The word 'cryptographic' can be left out if the rouines from the library
36		* being used are not cryptographic related :-).
37		* 4. If you include any Windows specific code (or a derivative thereof) from
38		* the apps directory (application code) you must include an acknowledgement:
39		* "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
40		*
41		* THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
42		* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
43		* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
44		* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
45		* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
46		* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
47		* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
48		* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
49		* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
50		* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
51		* SUCH DAMAGE.
52		*
53		* The licence and distribution terms for any publically available version or
54		* derivative of this code cannot be changed. i.e. this code cannot simply be
55		* copied and put under another distribution licence
56		* [including the GNU Public Licence.]
57		*/
58
59		#undef GENUINE_DSA
60
61		#ifdef GENUINE_DSA
62		/*
63		* Parameter generation follows the original release of FIPS PUB 186,
64		* Appendix 2.2 (i.e. use SHA as defined in FIPS PUB 180)
65		*/
66		# define HASH EVP_sha()
67		#else
68		/*
69		* Parameter generation follows the updated Appendix 2.2 for FIPS PUB 186,
70		* also Appendix 2.2 of FIPS PUB 186-1 (i.e. use SHA as defined in FIPS PUB
71		* 180-1)
72		*/
73		# define HASH EVP_sha1()
74		#endif
75
76		#include <openssl/opensslconf.h> /* To see if OPENSSL_NO_SHA is defined */
77
78		#ifndef OPENSSL_NO_SHA
79
80		# include <stdio.h>
81		# include "cryptlib.h"
82		# include <openssl/evp.h>
83		# include <openssl/bn.h>
84		# include <openssl/rand.h>
85		# include <openssl/sha.h>
86		# include "dsa_locl.h"
87
88		# ifdef OPENSSL_FIPS
89		/* Workaround bug in prototype */
90		# define fips_dsa_builtin_paramgen2 fips_dsa_paramgen_bad
91		# include <openssl/fips.h>
92		# endif
93
94		int DSA_generate_parameters_ex(DSA *ret, int bits,
95		const unsigned char *seed_in, int seed_len,
96		int counter_ret, unsigned long h_ret,
97		BN_GENCB *cb)
98	0	{
99		# ifdef OPENSSL_FIPS
100		if (FIPS_mode() && !(ret->meth->flags & DSA_FLAG_FIPS_METHOD)
101		&& !(ret->flags & DSA_FLAG_NON_FIPS_ALLOW)) {
102		DSAerr(DSA_F_DSA_GENERATE_PARAMETERS_EX, DSA_R_NON_FIPS_DSA_METHOD);
103		return 0;
104		}
105		# endif
106	0	if (ret->meth->dsa_paramgen)
107	0	return ret->meth->dsa_paramgen(ret, bits, seed_in, seed_len,
108	0	counter_ret, h_ret, cb);
109		# ifdef OPENSSL_FIPS
110		else if (FIPS_mode()) {
111		return FIPS_dsa_generate_parameters_ex(ret, bits,
112		seed_in, seed_len,
113		counter_ret, h_ret, cb);
114		}
115		# endif
116	0	else {
117	0	const EVP_MD *evpmd = bits >= 2048 ? EVP_sha256() : EVP_sha1();
118	0	size_t qbits = EVP_MD_size(evpmd) * 8;
119
120	0	return dsa_builtin_paramgen(ret, bits, qbits, evpmd,
121	0	seed_in, seed_len, NULL, counter_ret,
122	0	h_ret, cb);
123	0	}
124	0	}
125
126		int dsa_builtin_paramgen(DSA *ret, size_t bits, size_t qbits,
127		const EVP_MD evpmd, const unsigned char seed_in,
128		size_t seed_len, unsigned char *seed_out,
129		int counter_ret, unsigned long h_ret, BN_GENCB *cb)
130	0	{
131	0	int ok = 0;
132	0	unsigned char seed[SHA256_DIGEST_LENGTH];
133	0	unsigned char md[SHA256_DIGEST_LENGTH];
134	0	unsigned char buf[SHA256_DIGEST_LENGTH], buf2[SHA256_DIGEST_LENGTH];
135	0	BIGNUM r0, W, X, c, *test;
136	0	BIGNUM g = NULL, q = NULL, *p = NULL;
137	0	BN_MONT_CTX *mont = NULL;
138	0	int i, k, n = 0, m = 0, qsize = qbits >> 3;
139	0	int counter = 0;
140	0	int r = 0;
141	0	BN_CTX *ctx = NULL;
142	0	unsigned int h = 2;
143
144	0	if (qsize != SHA_DIGEST_LENGTH && qsize != SHA224_DIGEST_LENGTH &&
145	0	qsize != SHA256_DIGEST_LENGTH)
146		/* invalid q size */
147	0	return 0;
148
149	0	if (evpmd == NULL)
150		/* use SHA1 as default */
151	0	evpmd = EVP_sha1();
152
153	0	if (bits < 512)
154	0	bits = 512;
155
156	0	bits = (bits + 63) / 64 * 64;
157
158		/*
159		* NB: seed_len == 0 is special case: copy generated seed to seed_in if
160		* it is not NULL.
161		*/
162	0	if (seed_len && (seed_len < (size_t)qsize))
163	0	seed_in = NULL; /* seed buffer too small -- ignore */
164	0	if (seed_len > (size_t)qsize)
165	0	seed_len = qsize; /* App. 2.2 of FIPS PUB 186 allows larger
166		* SEED, but our internal buffers are
167		* restricted to 160 bits */
168	0	if (seed_in != NULL)
169	0	memcpy(seed, seed_in, seed_len);
170
171	0	if ((mont = BN_MONT_CTX_new()) == NULL)
172	0	goto err;
173
174	0	if ((ctx = BN_CTX_new()) == NULL)
175	0	goto err;
176
177	0	BN_CTX_start(ctx);
178
179	0	r0 = BN_CTX_get(ctx);
180	0	g = BN_CTX_get(ctx);
181	0	W = BN_CTX_get(ctx);
182	0	q = BN_CTX_get(ctx);
183	0	X = BN_CTX_get(ctx);
184	0	c = BN_CTX_get(ctx);
185	0	p = BN_CTX_get(ctx);
186	0	test = BN_CTX_get(ctx);
187
188	0	if (test == NULL)
189	0	goto err;
190
191	0	if (!BN_lshift(test, BN_value_one(), bits - 1))
192	0	goto err;
193
194	0	for (;;) {
195	0	for (;;) { /* find q */
196	0	int seed_is_random;
197
198		/* step 1 */
199	0	if (!BN_GENCB_call(cb, 0, m++))
200	0	goto err;
201
202	0	if (!seed_len \|\| !seed_in) {
203	0	if (RAND_bytes(seed, qsize) <= 0)
204	0	goto err;
205	0	seed_is_random = 1;
206	0	} else {
207	0	seed_is_random = 0;
208	0	seed_len = 0; /* use random seed if 'seed_in' turns out to
209		* be bad */
210	0	}
211	0	memcpy(buf, seed, qsize);
212	0	memcpy(buf2, seed, qsize);
213		/* precompute "SEED + 1" for step 7: */
214	0	for (i = qsize - 1; i >= 0; i--) {
215	0	buf[i]++;
216	0	if (buf[i] != 0)
217	0	break;
218	0	}
219
220		/* step 2 */
221	0	if (!EVP_Digest(seed, qsize, md, NULL, evpmd, NULL))
222	0	goto err;
223	0	if (!EVP_Digest(buf, qsize, buf2, NULL, evpmd, NULL))
224	0	goto err;
225	0	for (i = 0; i < qsize; i++)
226	0	md[i] ^= buf2[i];
227
228		/* step 3 */
229	0	md[0] \|= 0x80;
230	0	md[qsize - 1] \|= 0x01;
231	0	if (!BN_bin2bn(md, qsize, q))
232	0	goto err;
233
234		/* step 4 */
235	0	r = BN_is_prime_fasttest_ex(q, DSS_prime_checks, ctx,
236	0	seed_is_random, cb);
237	0	if (r > 0)
238	0	break;
239	0	if (r != 0)
240	0	goto err;
241
242		/* do a callback call */
243		/* step 5 */
244	0	}
245
246	0	if (!BN_GENCB_call(cb, 2, 0))
247	0	goto err;
248	0	if (!BN_GENCB_call(cb, 3, 0))
249	0	goto err;
250
251		/* step 6 */
252	0	counter = 0;
253		/* "offset = 2" */
254
255	0	n = (bits - 1) / 160;
256
257	0	for (;;) {
258	0	if ((counter != 0) && !BN_GENCB_call(cb, 0, counter))
259	0	goto err;
260
261		/* step 7 */
262	0	BN_zero(W);
263		/* now 'buf' contains "SEED + offset - 1" */
264	0	for (k = 0; k <= n; k++) {
265		/*
266		* obtain "SEED + offset + k" by incrementing:
267		*/
268	0	for (i = qsize - 1; i >= 0; i--) {
269	0	buf[i]++;
270	0	if (buf[i] != 0)
271	0	break;
272	0	}
273
274	0	if (!EVP_Digest(buf, qsize, md, NULL, evpmd, NULL))
275	0	goto err;
276
277		/* step 8 */
278	0	if (!BN_bin2bn(md, qsize, r0))
279	0	goto err;
280	0	if (!BN_lshift(r0, r0, (qsize << 3) * k))
281	0	goto err;
282	0	if (!BN_add(W, W, r0))
283	0	goto err;
284	0	}
285
286		/* more of step 8 */
287	0	if (!BN_mask_bits(W, bits - 1))
288	0	goto err;
289	0	if (!BN_copy(X, W))
290	0	goto err;
291	0	if (!BN_add(X, X, test))
292	0	goto err;
293
294		/* step 9 */
295	0	if (!BN_lshift1(r0, q))
296	0	goto err;
297	0	if (!BN_mod(c, X, r0, ctx))
298	0	goto err;
299	0	if (!BN_sub(r0, c, BN_value_one()))
300	0	goto err;
301	0	if (!BN_sub(p, X, r0))
302	0	goto err;
303
304		/* step 10 */
305	0	if (BN_cmp(p, test) >= 0) {
306		/* step 11 */
307	0	r = BN_is_prime_fasttest_ex(p, DSS_prime_checks, ctx, 1, cb);
308	0	if (r > 0)
309	0	goto end; /* found it */
310	0	if (r != 0)
311	0	goto err;
312	0	}
313
314		/* step 13 */
315	0	counter++;
316		/* "offset = offset + n + 1" */
317
318		/* step 14 */
319	0	if (counter >= 4096)
320	0	break;
321	0	}
322	0	}
323	0	end:
324	0	if (!BN_GENCB_call(cb, 2, 1))
325	0	goto err;
326
327		/* We now need to generate g */
328		/* Set r0=(p-1)/q */
329	0	if (!BN_sub(test, p, BN_value_one()))
330	0	goto err;
331	0	if (!BN_div(r0, NULL, test, q, ctx))
332	0	goto err;
333
334	0	if (!BN_set_word(test, h))
335	0	goto err;
336	0	if (!BN_MONT_CTX_set(mont, p, ctx))
337	0	goto err;
338
339	0	for (;;) {
340		/* g=test^r0%p */
341	0	if (!BN_mod_exp_mont(g, test, r0, p, ctx, mont))
342	0	goto err;
343	0	if (!BN_is_one(g))
344	0	break;
345	0	if (!BN_add(test, test, BN_value_one()))
346	0	goto err;
347	0	h++;
348	0	}
349
350	0	if (!BN_GENCB_call(cb, 3, 1))
351	0	goto err;
352
353	0	ok = 1;
354	0	err:
355	0	if (ok) {
356	0	if (ret->p)
357	0	BN_free(ret->p);
358	0	if (ret->q)
359	0	BN_free(ret->q);
360	0	if (ret->g)
361	0	BN_free(ret->g);
362	0	ret->p = BN_dup(p);
363	0	ret->q = BN_dup(q);
364	0	ret->g = BN_dup(g);
365	0	if (ret->p == NULL \|\| ret->q == NULL \|\| ret->g == NULL) {
366	0	ok = 0;
367	0	goto err;
368	0	}
369	0	if (counter_ret != NULL)
370	0	*counter_ret = counter;
371	0	if (h_ret != NULL)
372	0	*h_ret = h;
373	0	if (seed_out)
374	0	memcpy(seed_out, seed, qsize);
375	0	}
376	0	if (ctx) {
377	0	BN_CTX_end(ctx);
378	0	BN_CTX_free(ctx);
379	0	}
380	0	if (mont != NULL)
381	0	BN_MONT_CTX_free(mont);
382	0	return ok;
383	0	}
384
385		# ifdef OPENSSL_FIPS
386		# undef fips_dsa_builtin_paramgen2
387		extern int fips_dsa_builtin_paramgen2(DSA *ret, size_t L, size_t N,
388		const EVP_MD *evpmd,
389		const unsigned char *seed_in,
390		size_t seed_len, int idx,
391		unsigned char *seed_out,
392		int counter_ret, unsigned long h_ret,
393		BN_GENCB *cb);
394		# endif
395
396		/*
397		* This is a parameter generation algorithm for the DSA2 algorithm as
398		* described in FIPS 186-3.
399		*/
400
401		int dsa_builtin_paramgen2(DSA *ret, size_t L, size_t N,
402		const EVP_MD evpmd, const unsigned char seed_in,
403		size_t seed_len, int idx, unsigned char *seed_out,
404		int counter_ret, unsigned long h_ret,
405		BN_GENCB *cb)
406	0	{
407	0	int ok = -1;
408	0	unsigned char seed = NULL, seed_tmp = NULL;
409	0	unsigned char md[EVP_MAX_MD_SIZE];
410	0	int mdsize;
411	0	BIGNUM r0, W, X, c, *test;
412	0	BIGNUM g = NULL, q = NULL, *p = NULL;
413	0	BN_MONT_CTX *mont = NULL;
414	0	int i, k, n = 0, m = 0, qsize = N >> 3;
415	0	int counter = 0;
416	0	int r = 0;
417	0	BN_CTX *ctx = NULL;
418	0	EVP_MD_CTX mctx;
419	0	unsigned int h = 2;
420
421		# ifdef OPENSSL_FIPS
422
423		if (FIPS_mode())
424		return fips_dsa_builtin_paramgen2(ret, L, N, evpmd,
425		seed_in, seed_len, idx,
426		seed_out, counter_ret, h_ret, cb);
427		# endif
428
429	0	EVP_MD_CTX_init(&mctx);
430
431	0	if (evpmd == NULL) {
432	0	if (N == 160)
433	0	evpmd = EVP_sha1();
434	0	else if (N == 224)
435	0	evpmd = EVP_sha224();
436	0	else
437	0	evpmd = EVP_sha256();
438	0	}
439
440	0	mdsize = EVP_MD_size(evpmd);
441		/* If unverificable g generation only don't need seed */
442	0	if (!ret->p \|\| !ret->q \|\| idx >= 0) {
443	0	if (seed_len == 0)
444	0	seed_len = mdsize;
445
446	0	seed = OPENSSL_malloc(seed_len);
447
448	0	if (seed_out)
449	0	seed_tmp = seed_out;
450	0	else
451	0	seed_tmp = OPENSSL_malloc(seed_len);
452
453	0	if (!seed \|\| !seed_tmp)
454	0	goto err;
455
456	0	if (seed_in)
457	0	memcpy(seed, seed_in, seed_len);
458
459	0	}
460
461	0	if ((ctx = BN_CTX_new()) == NULL)
462	0	goto err;
463
464	0	if ((mont = BN_MONT_CTX_new()) == NULL)
465	0	goto err;
466
467	0	BN_CTX_start(ctx);
468	0	r0 = BN_CTX_get(ctx);
469	0	g = BN_CTX_get(ctx);
470	0	W = BN_CTX_get(ctx);
471	0	X = BN_CTX_get(ctx);
472	0	c = BN_CTX_get(ctx);
473	0	test = BN_CTX_get(ctx);
474
475		/* if p, q already supplied generate g only */
476	0	if (ret->p && ret->q) {
477	0	p = ret->p;
478	0	q = ret->q;
479	0	if (idx >= 0)
480	0	memcpy(seed_tmp, seed, seed_len);
481	0	goto g_only;
482	0	} else {
483	0	p = BN_CTX_get(ctx);
484	0	q = BN_CTX_get(ctx);
485	0	if (q == NULL)
486	0	goto err;
487	0	}
488
489	0	if (!BN_lshift(test, BN_value_one(), L - 1))
490	0	goto err;
491	0	for (;;) {
492	0	for (;;) { /* find q */
493	0	unsigned char *pmd;
494		/* step 1 */
495	0	if (!BN_GENCB_call(cb, 0, m++))
496	0	goto err;
497
498	0	if (!seed_in) {
499	0	if (RAND_bytes(seed, seed_len) <= 0)
500	0	goto err;
501	0	}
502		/* step 2 */
503	0	if (!EVP_Digest(seed, seed_len, md, NULL, evpmd, NULL))
504	0	goto err;
505		/* Take least significant bits of md */
506	0	if (mdsize > qsize)
507	0	pmd = md + mdsize - qsize;
508	0	else
509	0	pmd = md;
510
511	0	if (mdsize < qsize)
512	0	memset(md + mdsize, 0, qsize - mdsize);
513
514		/* step 3 */
515	0	pmd[0] \|= 0x80;
516	0	pmd[qsize - 1] \|= 0x01;
517	0	if (!BN_bin2bn(pmd, qsize, q))
518	0	goto err;
519
520		/* step 4 */
521	0	r = BN_is_prime_fasttest_ex(q, DSS_prime_checks, ctx,
522	0	seed_in ? 1 : 0, cb);
523	0	if (r > 0)
524	0	break;
525	0	if (r != 0)
526	0	goto err;
527		/* Provided seed didn't produce a prime: error */
528	0	if (seed_in) {
529	0	ok = 0;
530	0	DSAerr(DSA_F_DSA_BUILTIN_PARAMGEN2, DSA_R_Q_NOT_PRIME);
531	0	goto err;
532	0	}
533
534		/* do a callback call */
535		/* step 5 */
536	0	}
537		/* Copy seed to seed_out before we mess with it */
538	0	if (seed_out)
539	0	memcpy(seed_out, seed, seed_len);
540
541	0	if (!BN_GENCB_call(cb, 2, 0))
542	0	goto err;
543	0	if (!BN_GENCB_call(cb, 3, 0))
544	0	goto err;
545
546		/* step 6 */
547	0	counter = 0;
548		/* "offset = 1" */
549
550	0	n = (L - 1) / (mdsize << 3);
551
552	0	for (;;) {
553	0	if ((counter != 0) && !BN_GENCB_call(cb, 0, counter))
554	0	goto err;
555
556		/* step 7 */
557	0	BN_zero(W);
558		/* now 'buf' contains "SEED + offset - 1" */
559	0	for (k = 0; k <= n; k++) {
560		/*
561		* obtain "SEED + offset + k" by incrementing:
562		*/
563	0	for (i = seed_len - 1; i >= 0; i--) {
564	0	seed[i]++;
565	0	if (seed[i] != 0)
566	0	break;
567	0	}
568
569	0	if (!EVP_Digest(seed, seed_len, md, NULL, evpmd, NULL))
570	0	goto err;
571
572		/* step 8 */
573	0	if (!BN_bin2bn(md, mdsize, r0))
574	0	goto err;
575	0	if (!BN_lshift(r0, r0, (mdsize << 3) * k))
576	0	goto err;
577	0	if (!BN_add(W, W, r0))
578	0	goto err;
579	0	}
580
581		/* more of step 8 */
582	0	if (!BN_mask_bits(W, L - 1))
583	0	goto err;
584	0	if (!BN_copy(X, W))
585	0	goto err;
586	0	if (!BN_add(X, X, test))
587	0	goto err;
588
589		/* step 9 */
590	0	if (!BN_lshift1(r0, q))
591	0	goto err;
592	0	if (!BN_mod(c, X, r0, ctx))
593	0	goto err;
594	0	if (!BN_sub(r0, c, BN_value_one()))
595	0	goto err;
596	0	if (!BN_sub(p, X, r0))
597	0	goto err;
598
599		/* step 10 */
600	0	if (BN_cmp(p, test) >= 0) {
601		/* step 11 */
602	0	r = BN_is_prime_fasttest_ex(p, DSS_prime_checks, ctx, 1, cb);
603	0	if (r > 0)
604	0	goto end; /* found it */
605	0	if (r != 0)
606	0	goto err;
607	0	}
608
609		/* step 13 */
610	0	counter++;
611		/* "offset = offset + n + 1" */
612
613		/* step 14 */
614	0	if (counter >= (int)(4 * L))
615	0	break;
616	0	}
617	0	if (seed_in) {
618	0	ok = 0;
619	0	DSAerr(DSA_F_DSA_BUILTIN_PARAMGEN2, DSA_R_INVALID_PARAMETERS);
620	0	goto err;
621	0	}
622	0	}
623	0	end:
624	0	if (!BN_GENCB_call(cb, 2, 1))
625	0	goto err;
626
627	0	g_only:
628
629		/* We now need to generate g */
630		/* Set r0=(p-1)/q */
631	0	if (!BN_sub(test, p, BN_value_one()))
632	0	goto err;
633	0	if (!BN_div(r0, NULL, test, q, ctx))
634	0	goto err;
635
636	0	if (idx < 0) {
637	0	if (!BN_set_word(test, h))
638	0	goto err;
639	0	} else
640	0	h = 1;
641	0	if (!BN_MONT_CTX_set(mont, p, ctx))
642	0	goto err;
643
644	0	for (;;) {
645	0	static const unsigned char ggen[4] = { 0x67, 0x67, 0x65, 0x6e };
646	0	if (idx >= 0) {
647	0	md[0] = idx & 0xff;
648	0	md[1] = (h >> 8) & 0xff;
649	0	md[2] = h & 0xff;
650	0	if (!EVP_DigestInit_ex(&mctx, evpmd, NULL))
651	0	goto err;
652	0	if (!EVP_DigestUpdate(&mctx, seed_tmp, seed_len))
653	0	goto err;
654	0	if (!EVP_DigestUpdate(&mctx, ggen, sizeof(ggen)))
655	0	goto err;
656	0	if (!EVP_DigestUpdate(&mctx, md, 3))
657	0	goto err;
658	0	if (!EVP_DigestFinal_ex(&mctx, md, NULL))
659	0	goto err;
660	0	if (!BN_bin2bn(md, mdsize, test))
661	0	goto err;
662	0	}
663		/* g=test^r0%p */
664	0	if (!BN_mod_exp_mont(g, test, r0, p, ctx, mont))
665	0	goto err;
666	0	if (!BN_is_one(g))
667	0	break;
668	0	if (idx < 0 && !BN_add(test, test, BN_value_one()))
669	0	goto err;
670	0	h++;
671	0	if (idx >= 0 && h > 0xffff)
672	0	goto err;
673	0	}
674
675	0	if (!BN_GENCB_call(cb, 3, 1))
676	0	goto err;
677
678	0	ok = 1;
679	0	err:
680	0	if (ok == 1) {
681	0	if (p != ret->p) {
682	0	if (ret->p)
683	0	BN_free(ret->p);
684	0	ret->p = BN_dup(p);
685	0	}
686	0	if (q != ret->q) {
687	0	if (ret->q)
688	0	BN_free(ret->q);
689	0	ret->q = BN_dup(q);
690	0	}
691	0	if (ret->g)
692	0	BN_free(ret->g);
693	0	ret->g = BN_dup(g);
694	0	if (ret->p == NULL \|\| ret->q == NULL \|\| ret->g == NULL) {
695	0	ok = -1;
696	0	goto err;
697	0	}
698	0	if (counter_ret != NULL)
699	0	*counter_ret = counter;
700	0	if (h_ret != NULL)
701	0	*h_ret = h;
702	0	}
703	0	if (seed)
704	0	OPENSSL_free(seed);
705	0	if (seed_out != seed_tmp)
706	0	OPENSSL_free(seed_tmp);
707	0	if (ctx) {
708	0	BN_CTX_end(ctx);
709	0	BN_CTX_free(ctx);
710	0	}
711	0	if (mont != NULL)
712	0	BN_MONT_CTX_free(mont);
713	0	EVP_MD_CTX_cleanup(&mctx);
714	0	return ok;
715	0	}
716
717		int dsa_paramgen_check_g(DSA *dsa)
718	0	{
719	0	BN_CTX *ctx;
720	0	BIGNUM *tmp;
721	0	BN_MONT_CTX *mont = NULL;
722	0	int rv = -1;
723	0	ctx = BN_CTX_new();
724	0	if (!ctx)
725	0	return -1;
726	0	BN_CTX_start(ctx);
727	0	if (BN_cmp(dsa->g, BN_value_one()) <= 0)
728	0	return 0;
729	0	if (BN_cmp(dsa->g, dsa->p) >= 0)
730	0	return 0;
731	0	tmp = BN_CTX_get(ctx);
732	0	if (!tmp)
733	0	goto err;
734	0	if ((mont = BN_MONT_CTX_new()) == NULL)
735	0	goto err;
736	0	if (!BN_MONT_CTX_set(mont, dsa->p, ctx))
737	0	goto err;
738		/* Work out g^q mod p */
739	0	if (!BN_mod_exp_mont(tmp, dsa->g, dsa->q, dsa->p, ctx, mont))
740	0	goto err;
741	0	if (!BN_cmp(tmp, BN_value_one()))
742	0	rv = 1;
743	0	else
744	0	rv = 0;
745	0	err:
746	0	BN_CTX_end(ctx);
747	0	if (mont)
748	0	BN_MONT_CTX_free(mont);
749	0	BN_CTX_free(ctx);
750	0	return rv;
751
752	0	}
753		#endif