/src/openssl111/crypto/dsa/dsa_gen.c

Source (jump to first uncovered line)
/*
 * Copyright 1995-2019 The OpenSSL Project Authors. All Rights Reserved.
 *
 * Licensed under the OpenSSL license (the "License").  You may not use
 * this file except in compliance with the License.  You can obtain a copy
 * in the file LICENSE in the source distribution or at
 * https://www.openssl.org/source/license.html
 */

/*
 * 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 xxxHASH    EVP_sha1()

#include <openssl/opensslconf.h>
#include <stdio.h>
#include "internal/cryptlib.h"
#include <openssl/evp.h>
#include <openssl/bn.h>
#include <openssl/rand.h>
#include <openssl/sha.h>
#include "dsa_local.h"

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)
{
    if (ret->meth->dsa_paramgen)
        return ret->meth->dsa_paramgen(ret, bits, seed_in, seed_len,
                                       counter_ret, h_ret, cb);
    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) {
        if (qsize == SHA_DIGEST_LENGTH)
            evpmd = EVP_sha1();
        else if (qsize == SHA224_DIGEST_LENGTH)
            evpmd = EVP_sha224();
        else
            evpmd = EVP_sha256();
    } else {
        qsize = EVP_MD_size(evpmd);
    }

    if (bits < 512)
        bits = 512;

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

    if (seed_in != NULL) {
        if (seed_len < (size_t)qsize) {
            DSAerr(DSA_F_DSA_BUILTIN_PARAMGEN, DSA_R_SEED_LEN_SMALL);
            return 0;
        }
        if (seed_len > (size_t)qsize) {
            /* Only consume as much seed as is expected. */
            seed_len = qsize;
        }
        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 use_random_seed = (seed_in == NULL);

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

            if (use_random_seed) {
                if (RAND_bytes(seed, qsize) <= 0)
                    goto err;
            } else {
                /* If we come back through, use random seed next time. */
                seed_in = NULL;
            }
            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,
                                        use_random_seed, 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) {
        BN_free(ret->p);
        BN_free(ret->q);
        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);
    }
    BN_CTX_end(ctx);
    BN_CTX_free(ctx);
    BN_MONT_CTX_free(mont);
    return ok;
}

/*
 * 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 = EVP_MD_CTX_new();
    unsigned int h = 2;

    if (mctx == NULL)
        goto err;

    /* make sure L > N, otherwise we'll get trapped in an infinite loop */
    if (L <= N) {
        DSAerr(DSA_F_DSA_BUILTIN_PARAMGEN2, DSA_R_INVALID_PARAMETERS);
        goto err;
    }

    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 unverifiable 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 == NULL || seed_tmp == NULL)
            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 (test == NULL)
        goto err;

    /* 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) {
            BN_free(ret->p);
            ret->p = BN_dup(p);
        }
        if (q != ret->q) {
            BN_free(ret->q);
            ret->q = BN_dup(q);
        }
        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;
    }
    OPENSSL_free(seed);
    if (seed_out != seed_tmp)
        OPENSSL_free(seed_tmp);
    BN_CTX_end(ctx);
    BN_CTX_free(ctx);
    BN_MONT_CTX_free(mont);
    EVP_MD_CTX_free(mctx);
    return ok;
}

Coverage Report

Created: 2023-09-25 06:45

Line	Count	Source (jump to first uncovered line)
1		/*
2		* Copyright 1995-2019 The OpenSSL Project Authors. All Rights Reserved.
3		*
4		* Licensed under the OpenSSL license (the "License"). You may not use
5		* this file except in compliance with the License. You can obtain a copy
6		* in the file LICENSE in the source distribution or at
7		* https://www.openssl.org/source/license.html
8		*/
9
10		/*
11		* Parameter generation follows the updated Appendix 2.2 for FIPS PUB 186,
12		* also Appendix 2.2 of FIPS PUB 186-1 (i.e. use SHA as defined in FIPS PUB
13		* 180-1)
14		*/
15		#define xxxHASH EVP_sha1()
16
17		#include <openssl/opensslconf.h>
18		#include <stdio.h>
19		#include "internal/cryptlib.h"
20		#include <openssl/evp.h>
21		#include <openssl/bn.h>
22		#include <openssl/rand.h>
23		#include <openssl/sha.h>
24		#include "dsa_local.h"
25
26		int DSA_generate_parameters_ex(DSA *ret, int bits,
27		const unsigned char *seed_in, int seed_len,
28		int counter_ret, unsigned long h_ret,
29		BN_GENCB *cb)
30	0	{
31	0	if (ret->meth->dsa_paramgen)
32	0	return ret->meth->dsa_paramgen(ret, bits, seed_in, seed_len,
33	0	counter_ret, h_ret, cb);
34	0	else {
35	0	const EVP_MD *evpmd = bits >= 2048 ? EVP_sha256() : EVP_sha1();
36	0	size_t qbits = EVP_MD_size(evpmd) * 8;
37
38	0	return dsa_builtin_paramgen(ret, bits, qbits, evpmd,
39	0	seed_in, seed_len, NULL, counter_ret,
40	0	h_ret, cb);
41	0	}
42	0	}
43
44		int dsa_builtin_paramgen(DSA *ret, size_t bits, size_t qbits,
45		const EVP_MD evpmd, const unsigned char seed_in,
46		size_t seed_len, unsigned char *seed_out,
47		int counter_ret, unsigned long h_ret, BN_GENCB *cb)
48	0	{
49	0	int ok = 0;
50	0	unsigned char seed[SHA256_DIGEST_LENGTH];
51	0	unsigned char md[SHA256_DIGEST_LENGTH];
52	0	unsigned char buf[SHA256_DIGEST_LENGTH], buf2[SHA256_DIGEST_LENGTH];
53	0	BIGNUM r0, W, X, c, *test;
54	0	BIGNUM g = NULL, q = NULL, *p = NULL;
55	0	BN_MONT_CTX *mont = NULL;
56	0	int i, k, n = 0, m = 0, qsize = qbits >> 3;
57	0	int counter = 0;
58	0	int r = 0;
59	0	BN_CTX *ctx = NULL;
60	0	unsigned int h = 2;
61
62	0	if (qsize != SHA_DIGEST_LENGTH && qsize != SHA224_DIGEST_LENGTH &&
63	0	qsize != SHA256_DIGEST_LENGTH)
64		/* invalid q size */
65	0	return 0;
66
67	0	if (evpmd == NULL) {
68	0	if (qsize == SHA_DIGEST_LENGTH)
69	0	evpmd = EVP_sha1();
70	0	else if (qsize == SHA224_DIGEST_LENGTH)
71	0	evpmd = EVP_sha224();
72	0	else
73	0	evpmd = EVP_sha256();
74	0	} else {
75	0	qsize = EVP_MD_size(evpmd);
76	0	}
77
78	0	if (bits < 512)
79	0	bits = 512;
80
81	0	bits = (bits + 63) / 64 * 64;
82
83	0	if (seed_in != NULL) {
84	0	if (seed_len < (size_t)qsize) {
85	0	DSAerr(DSA_F_DSA_BUILTIN_PARAMGEN, DSA_R_SEED_LEN_SMALL);
86	0	return 0;
87	0	}
88	0	if (seed_len > (size_t)qsize) {
89		/* Only consume as much seed as is expected. */
90	0	seed_len = qsize;
91	0	}
92	0	memcpy(seed, seed_in, seed_len);
93	0	}
94
95	0	if ((mont = BN_MONT_CTX_new()) == NULL)
96	0	goto err;
97
98	0	if ((ctx = BN_CTX_new()) == NULL)
99	0	goto err;
100
101	0	BN_CTX_start(ctx);
102
103	0	r0 = BN_CTX_get(ctx);
104	0	g = BN_CTX_get(ctx);
105	0	W = BN_CTX_get(ctx);
106	0	q = BN_CTX_get(ctx);
107	0	X = BN_CTX_get(ctx);
108	0	c = BN_CTX_get(ctx);
109	0	p = BN_CTX_get(ctx);
110	0	test = BN_CTX_get(ctx);
111
112	0	if (test == NULL)
113	0	goto err;
114
115	0	if (!BN_lshift(test, BN_value_one(), bits - 1))
116	0	goto err;
117
118	0	for (;;) {
119	0	for (;;) { /* find q */
120	0	int use_random_seed = (seed_in == NULL);
121
122		/* step 1 */
123	0	if (!BN_GENCB_call(cb, 0, m++))
124	0	goto err;
125
126	0	if (use_random_seed) {
127	0	if (RAND_bytes(seed, qsize) <= 0)
128	0	goto err;
129	0	} else {
130		/* If we come back through, use random seed next time. */
131	0	seed_in = NULL;
132	0	}
133	0	memcpy(buf, seed, qsize);
134	0	memcpy(buf2, seed, qsize);
135		/* precompute "SEED + 1" for step 7: */
136	0	for (i = qsize - 1; i >= 0; i--) {
137	0	buf[i]++;
138	0	if (buf[i] != 0)
139	0	break;
140	0	}
141
142		/* step 2 */
143	0	if (!EVP_Digest(seed, qsize, md, NULL, evpmd, NULL))
144	0	goto err;
145	0	if (!EVP_Digest(buf, qsize, buf2, NULL, evpmd, NULL))
146	0	goto err;
147	0	for (i = 0; i < qsize; i++)
148	0	md[i] ^= buf2[i];
149
150		/* step 3 */
151	0	md[0] \|= 0x80;
152	0	md[qsize - 1] \|= 0x01;
153	0	if (!BN_bin2bn(md, qsize, q))
154	0	goto err;
155
156		/* step 4 */
157	0	r = BN_is_prime_fasttest_ex(q, DSS_prime_checks, ctx,
158	0	use_random_seed, cb);
159	0	if (r > 0)
160	0	break;
161	0	if (r != 0)
162	0	goto err;
163
164		/* do a callback call */
165		/* step 5 */
166	0	}
167
168	0	if (!BN_GENCB_call(cb, 2, 0))
169	0	goto err;
170	0	if (!BN_GENCB_call(cb, 3, 0))
171	0	goto err;
172
173		/* step 6 */
174	0	counter = 0;
175		/* "offset = 2" */
176
177	0	n = (bits - 1) / 160;
178
179	0	for (;;) {
180	0	if ((counter != 0) && !BN_GENCB_call(cb, 0, counter))
181	0	goto err;
182
183		/* step 7 */
184	0	BN_zero(W);
185		/* now 'buf' contains "SEED + offset - 1" */
186	0	for (k = 0; k <= n; k++) {
187		/*
188		* obtain "SEED + offset + k" by incrementing:
189		*/
190	0	for (i = qsize - 1; i >= 0; i--) {
191	0	buf[i]++;
192	0	if (buf[i] != 0)
193	0	break;
194	0	}
195
196	0	if (!EVP_Digest(buf, qsize, md, NULL, evpmd, NULL))
197	0	goto err;
198
199		/* step 8 */
200	0	if (!BN_bin2bn(md, qsize, r0))
201	0	goto err;
202	0	if (!BN_lshift(r0, r0, (qsize << 3) * k))
203	0	goto err;
204	0	if (!BN_add(W, W, r0))
205	0	goto err;
206	0	}
207
208		/* more of step 8 */
209	0	if (!BN_mask_bits(W, bits - 1))
210	0	goto err;
211	0	if (!BN_copy(X, W))
212	0	goto err;
213	0	if (!BN_add(X, X, test))
214	0	goto err;
215
216		/* step 9 */
217	0	if (!BN_lshift1(r0, q))
218	0	goto err;
219	0	if (!BN_mod(c, X, r0, ctx))
220	0	goto err;
221	0	if (!BN_sub(r0, c, BN_value_one()))
222	0	goto err;
223	0	if (!BN_sub(p, X, r0))
224	0	goto err;
225
226		/* step 10 */
227	0	if (BN_cmp(p, test) >= 0) {
228		/* step 11 */
229	0	r = BN_is_prime_fasttest_ex(p, DSS_prime_checks, ctx, 1, cb);
230	0	if (r > 0)
231	0	goto end; /* found it */
232	0	if (r != 0)
233	0	goto err;
234	0	}
235
236		/* step 13 */
237	0	counter++;
238		/* "offset = offset + n + 1" */
239
240		/* step 14 */
241	0	if (counter >= 4096)
242	0	break;
243	0	}
244	0	}
245	0	end:
246	0	if (!BN_GENCB_call(cb, 2, 1))
247	0	goto err;
248
249		/* We now need to generate g */
250		/* Set r0=(p-1)/q */
251	0	if (!BN_sub(test, p, BN_value_one()))
252	0	goto err;
253	0	if (!BN_div(r0, NULL, test, q, ctx))
254	0	goto err;
255
256	0	if (!BN_set_word(test, h))
257	0	goto err;
258	0	if (!BN_MONT_CTX_set(mont, p, ctx))
259	0	goto err;
260
261	0	for (;;) {
262		/* g=test^r0%p */
263	0	if (!BN_mod_exp_mont(g, test, r0, p, ctx, mont))
264	0	goto err;
265	0	if (!BN_is_one(g))
266	0	break;
267	0	if (!BN_add(test, test, BN_value_one()))
268	0	goto err;
269	0	h++;
270	0	}
271
272	0	if (!BN_GENCB_call(cb, 3, 1))
273	0	goto err;
274
275	0	ok = 1;
276	0	err:
277	0	if (ok) {
278	0	BN_free(ret->p);
279	0	BN_free(ret->q);
280	0	BN_free(ret->g);
281	0	ret->p = BN_dup(p);
282	0	ret->q = BN_dup(q);
283	0	ret->g = BN_dup(g);
284	0	if (ret->p == NULL \|\| ret->q == NULL \|\| ret->g == NULL) {
285	0	ok = 0;
286	0	goto err;
287	0	}
288	0	if (counter_ret != NULL)
289	0	*counter_ret = counter;
290	0	if (h_ret != NULL)
291	0	*h_ret = h;
292	0	if (seed_out)
293	0	memcpy(seed_out, seed, qsize);
294	0	}
295	0	BN_CTX_end(ctx);
296	0	BN_CTX_free(ctx);
297	0	BN_MONT_CTX_free(mont);
298	0	return ok;
299	0	}
300
301		/*
302		* This is a parameter generation algorithm for the DSA2 algorithm as
303		* described in FIPS 186-3.
304		*/
305
306		int dsa_builtin_paramgen2(DSA *ret, size_t L, size_t N,
307		const EVP_MD evpmd, const unsigned char seed_in,
308		size_t seed_len, int idx, unsigned char *seed_out,
309		int counter_ret, unsigned long h_ret,
310		BN_GENCB *cb)
311	0	{
312	0	int ok = -1;
313	0	unsigned char seed = NULL, seed_tmp = NULL;
314	0	unsigned char md[EVP_MAX_MD_SIZE];
315	0	int mdsize;
316	0	BIGNUM r0, W, X, c, *test;
317	0	BIGNUM g = NULL, q = NULL, *p = NULL;
318	0	BN_MONT_CTX *mont = NULL;
319	0	int i, k, n = 0, m = 0, qsize = N >> 3;
320	0	int counter = 0;
321	0	int r = 0;
322	0	BN_CTX *ctx = NULL;
323	0	EVP_MD_CTX *mctx = EVP_MD_CTX_new();
324	0	unsigned int h = 2;
325
326	0	if (mctx == NULL)
327	0	goto err;
328
329		/* make sure L > N, otherwise we'll get trapped in an infinite loop */
330	0	if (L <= N) {
331	0	DSAerr(DSA_F_DSA_BUILTIN_PARAMGEN2, DSA_R_INVALID_PARAMETERS);
332	0	goto err;
333	0	}
334
335	0	if (evpmd == NULL) {
336	0	if (N == 160)
337	0	evpmd = EVP_sha1();
338	0	else if (N == 224)
339	0	evpmd = EVP_sha224();
340	0	else
341	0	evpmd = EVP_sha256();
342	0	}
343
344	0	mdsize = EVP_MD_size(evpmd);
345		/* If unverifiable g generation only don't need seed */
346	0	if (!ret->p \|\| !ret->q \|\| idx >= 0) {
347	0	if (seed_len == 0)
348	0	seed_len = mdsize;
349
350	0	seed = OPENSSL_malloc(seed_len);
351
352	0	if (seed_out)
353	0	seed_tmp = seed_out;
354	0	else
355	0	seed_tmp = OPENSSL_malloc(seed_len);
356
357	0	if (seed == NULL \|\| seed_tmp == NULL)
358	0	goto err;
359
360	0	if (seed_in)
361	0	memcpy(seed, seed_in, seed_len);
362
363	0	}
364
365	0	if ((ctx = BN_CTX_new()) == NULL)
366	0	goto err;
367
368	0	if ((mont = BN_MONT_CTX_new()) == NULL)
369	0	goto err;
370
371	0	BN_CTX_start(ctx);
372	0	r0 = BN_CTX_get(ctx);
373	0	g = BN_CTX_get(ctx);
374	0	W = BN_CTX_get(ctx);
375	0	X = BN_CTX_get(ctx);
376	0	c = BN_CTX_get(ctx);
377	0	test = BN_CTX_get(ctx);
378	0	if (test == NULL)
379	0	goto err;
380
381		/* if p, q already supplied generate g only */
382	0	if (ret->p && ret->q) {
383	0	p = ret->p;
384	0	q = ret->q;
385	0	if (idx >= 0)
386	0	memcpy(seed_tmp, seed, seed_len);
387	0	goto g_only;
388	0	} else {
389	0	p = BN_CTX_get(ctx);
390	0	q = BN_CTX_get(ctx);
391	0	if (q == NULL)
392	0	goto err;
393	0	}
394
395	0	if (!BN_lshift(test, BN_value_one(), L - 1))
396	0	goto err;
397	0	for (;;) {
398	0	for (;;) { /* find q */
399	0	unsigned char *pmd;
400		/* step 1 */
401	0	if (!BN_GENCB_call(cb, 0, m++))
402	0	goto err;
403
404	0	if (!seed_in) {
405	0	if (RAND_bytes(seed, seed_len) <= 0)
406	0	goto err;
407	0	}
408		/* step 2 */
409	0	if (!EVP_Digest(seed, seed_len, md, NULL, evpmd, NULL))
410	0	goto err;
411		/* Take least significant bits of md */
412	0	if (mdsize > qsize)
413	0	pmd = md + mdsize - qsize;
414	0	else
415	0	pmd = md;
416
417	0	if (mdsize < qsize)
418	0	memset(md + mdsize, 0, qsize - mdsize);
419
420		/* step 3 */
421	0	pmd[0] \|= 0x80;
422	0	pmd[qsize - 1] \|= 0x01;
423	0	if (!BN_bin2bn(pmd, qsize, q))
424	0	goto err;
425
426		/* step 4 */
427	0	r = BN_is_prime_fasttest_ex(q, DSS_prime_checks, ctx,
428	0	seed_in ? 1 : 0, cb);
429	0	if (r > 0)
430	0	break;
431	0	if (r != 0)
432	0	goto err;
433		/* Provided seed didn't produce a prime: error */
434	0	if (seed_in) {
435	0	ok = 0;
436	0	DSAerr(DSA_F_DSA_BUILTIN_PARAMGEN2, DSA_R_Q_NOT_PRIME);
437	0	goto err;
438	0	}
439
440		/* do a callback call */
441		/* step 5 */
442	0	}
443		/* Copy seed to seed_out before we mess with it */
444	0	if (seed_out)
445	0	memcpy(seed_out, seed, seed_len);
446
447	0	if (!BN_GENCB_call(cb, 2, 0))
448	0	goto err;
449	0	if (!BN_GENCB_call(cb, 3, 0))
450	0	goto err;
451
452		/* step 6 */
453	0	counter = 0;
454		/* "offset = 1" */
455
456	0	n = (L - 1) / (mdsize << 3);
457
458	0	for (;;) {
459	0	if ((counter != 0) && !BN_GENCB_call(cb, 0, counter))
460	0	goto err;
461
462		/* step 7 */
463	0	BN_zero(W);
464		/* now 'buf' contains "SEED + offset - 1" */
465	0	for (k = 0; k <= n; k++) {
466		/*
467		* obtain "SEED + offset + k" by incrementing:
468		*/
469	0	for (i = seed_len - 1; i >= 0; i--) {
470	0	seed[i]++;
471	0	if (seed[i] != 0)
472	0	break;
473	0	}
474
475	0	if (!EVP_Digest(seed, seed_len, md, NULL, evpmd, NULL))
476	0	goto err;
477
478		/* step 8 */
479	0	if (!BN_bin2bn(md, mdsize, r0))
480	0	goto err;
481	0	if (!BN_lshift(r0, r0, (mdsize << 3) * k))
482	0	goto err;
483	0	if (!BN_add(W, W, r0))
484	0	goto err;
485	0	}
486
487		/* more of step 8 */
488	0	if (!BN_mask_bits(W, L - 1))
489	0	goto err;
490	0	if (!BN_copy(X, W))
491	0	goto err;
492	0	if (!BN_add(X, X, test))
493	0	goto err;
494
495		/* step 9 */
496	0	if (!BN_lshift1(r0, q))
497	0	goto err;
498	0	if (!BN_mod(c, X, r0, ctx))
499	0	goto err;
500	0	if (!BN_sub(r0, c, BN_value_one()))
501	0	goto err;
502	0	if (!BN_sub(p, X, r0))
503	0	goto err;
504
505		/* step 10 */
506	0	if (BN_cmp(p, test) >= 0) {
507		/* step 11 */
508	0	r = BN_is_prime_fasttest_ex(p, DSS_prime_checks, ctx, 1, cb);
509	0	if (r > 0)
510	0	goto end; /* found it */
511	0	if (r != 0)
512	0	goto err;
513	0	}
514
515		/* step 13 */
516	0	counter++;
517		/* "offset = offset + n + 1" */
518
519		/* step 14 */
520	0	if (counter >= (int)(4 * L))
521	0	break;
522	0	}
523	0	if (seed_in) {
524	0	ok = 0;
525	0	DSAerr(DSA_F_DSA_BUILTIN_PARAMGEN2, DSA_R_INVALID_PARAMETERS);
526	0	goto err;
527	0	}
528	0	}
529	0	end:
530	0	if (!BN_GENCB_call(cb, 2, 1))
531	0	goto err;
532
533	0	g_only:
534
535		/* We now need to generate g */
536		/* Set r0=(p-1)/q */
537	0	if (!BN_sub(test, p, BN_value_one()))
538	0	goto err;
539	0	if (!BN_div(r0, NULL, test, q, ctx))
540	0	goto err;
541
542	0	if (idx < 0) {
543	0	if (!BN_set_word(test, h))
544	0	goto err;
545	0	} else
546	0	h = 1;
547	0	if (!BN_MONT_CTX_set(mont, p, ctx))
548	0	goto err;
549
550	0	for (;;) {
551	0	static const unsigned char ggen[4] = { 0x67, 0x67, 0x65, 0x6e };
552	0	if (idx >= 0) {
553	0	md[0] = idx & 0xff;
554	0	md[1] = (h >> 8) & 0xff;
555	0	md[2] = h & 0xff;
556	0	if (!EVP_DigestInit_ex(mctx, evpmd, NULL))
557	0	goto err;
558	0	if (!EVP_DigestUpdate(mctx, seed_tmp, seed_len))
559	0	goto err;
560	0	if (!EVP_DigestUpdate(mctx, ggen, sizeof(ggen)))
561	0	goto err;
562	0	if (!EVP_DigestUpdate(mctx, md, 3))
563	0	goto err;
564	0	if (!EVP_DigestFinal_ex(mctx, md, NULL))
565	0	goto err;
566	0	if (!BN_bin2bn(md, mdsize, test))
567	0	goto err;
568	0	}
569		/* g=test^r0%p */
570	0	if (!BN_mod_exp_mont(g, test, r0, p, ctx, mont))
571	0	goto err;
572	0	if (!BN_is_one(g))
573	0	break;
574	0	if (idx < 0 && !BN_add(test, test, BN_value_one()))
575	0	goto err;
576	0	h++;
577	0	if (idx >= 0 && h > 0xffff)
578	0	goto err;
579	0	}
580
581	0	if (!BN_GENCB_call(cb, 3, 1))
582	0	goto err;
583
584	0	ok = 1;
585	0	err:
586	0	if (ok == 1) {
587	0	if (p != ret->p) {
588	0	BN_free(ret->p);
589	0	ret->p = BN_dup(p);
590	0	}
591	0	if (q != ret->q) {
592	0	BN_free(ret->q);
593	0	ret->q = BN_dup(q);
594	0	}
595	0	BN_free(ret->g);
596	0	ret->g = BN_dup(g);
597	0	if (ret->p == NULL \|\| ret->q == NULL \|\| ret->g == NULL) {
598	0	ok = -1;
599	0	goto err;
600	0	}
601	0	if (counter_ret != NULL)
602	0	*counter_ret = counter;
603	0	if (h_ret != NULL)
604	0	*h_ret = h;
605	0	}
606	0	OPENSSL_free(seed);
607	0	if (seed_out != seed_tmp)
608	0	OPENSSL_free(seed_tmp);
609	0	BN_CTX_end(ctx);
610	0	BN_CTX_free(ctx);
611	0	BN_MONT_CTX_free(mont);
612	0	EVP_MD_CTX_free(mctx);
613	0	return ok;
614	0	}