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openssl/crypto/dsa/dsa_gen.c
Rich Salz 474e469bbd OPENSSL_NO_xxx cleanup: SHA 
Remove support for SHA0 and DSS0 (they were broken), and remove
the ability to attempt to build without SHA (it didn't work).
For simplicity, remove the option of not building various SHA algorithms;
you could argue that SHA_224/256/384/512 should be kept, since they're
like crypto algorithms, but I decided to go the other way.
So these options are gone:
	GENUINE_DSA         OPENSSL_NO_SHA0
	OPENSSL_NO_SHA      OPENSSL_NO_SHA1
	OPENSSL_NO_SHA224   OPENSSL_NO_SHA256
	OPENSSL_NO_SHA384   OPENSSL_NO_SHA512

Reviewed-by: Richard Levitte <levitte@openssl.org>
2015-01-27 12:34:45 -05:00

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/* 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.]
*/
/*
* 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> /* To see if OPENSSL_NO_SHA is defined */
#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"
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;
size_t qbits = bits >= 2048 ? 256 : 160;
if (bits >= 2048) {
qbits = 256;
evpmd = EVP_sha256();
} else {
qbits = 160;
evpmd = EVP_sha1();
}
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 ((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);
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 (!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) {
if (RAND_pseudo_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;
}
/*
* 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;
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 = M_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 (!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_pseudo_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;
}
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