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openssl/crypto/dsa/dsa_gen.c

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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.]
*/
#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
#define OPENSSL_FIPSAPI
#include <stdio.h>
#include "cryptlib.h"
#include <openssl/evp.h>
#include <openssl/bn.h>
#include <openssl/rand.h>
#include <openssl/sha.h>
#ifdef OPENSSL_FIPS
#include <openssl/fips.h>
#include <openssl/fips_rand.h>
#endif
#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;
#ifdef OPENSSL_FIPS
if(FIPS_selftest_failed())
{
FIPSerr(FIPS_F_DSA_BUILTIN_PARAMGEN, FIPS_R_FIPS_SELFTEST_FAILED);
goto err;
}
if (FIPS_module_mode() && !(ret->flags & DSA_FLAG_NON_FIPS_ALLOW)
&& (bits < OPENSSL_DSA_FIPS_MIN_MODULUS_BITS))
{
DSAerr(DSA_F_DSA_BUILTIN_PARAMGEN, DSA_R_KEY_SIZE_TOO_SMALL);
goto err;
}
#endif
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;
}
#ifdef OPENSSL_FIPS
/* Security strength of parameter values for (L,N): see FIPS186-3 4.2
* and SP800-131A
*/
static int fips_ffc_strength(size_t L, size_t N)
{
if (L >= 15360 && N >= 512)
return 256;
if (L >= 7680 && N >= 384)
return 192;
if (L >= 3072 && N >= 256)
return 128;
if (L >= 2048 && N >= 224)
return 112;
if (L >= 1024 && N >= 160)
return 80;
return 0;
}
/* Valid DSA2 parameters from FIPS 186-3 */
static int dsa2_valid_parameters(size_t L, size_t N)
{
if (L == 1024 && N == 160)
return 80;
if (L == 2048 && N == 224)
return 112;
if (L == 2048 && N == 256)
return 112;
if (L == 3072 && N == 256)
return 128;
return 0;
}
int fips_check_dsa_prng(DSA *dsa, size_t L, size_t N)
{
int strength;
if (!FIPS_module_mode())
return 1;
if (dsa->flags & (DSA_FLAG_NON_FIPS_ALLOW|DSA_FLAG_FIPS_CHECKED))
return 1;
if (!L || !N)
{
L = BN_num_bits(dsa->p);
N = BN_num_bits(dsa->q);
}
if (!dsa2_valid_parameters(L, N))
{
FIPSerr(FIPS_F_FIPS_CHECK_DSA_PRNG, FIPS_R_INVALID_PARAMETERS);
return 0;
}
strength = fips_ffc_strength(L, N);
if (!strength)
{
FIPSerr(FIPS_F_FIPS_CHECK_DSA_PRNG,FIPS_R_KEY_TOO_SHORT);
return 0;
}
if (FIPS_rand_strength() >= strength)
return 1;
FIPSerr(FIPS_F_FIPS_CHECK_DSA_PRNG,FIPS_R_PRNG_STRENGTH_TOO_LOW);
return 0;
}
#endif /* OPENSSL_FIPS */
/* 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);
#ifdef OPENSSL_FIPS
if(FIPS_selftest_failed())
{
FIPSerr(FIPS_F_DSA_BUILTIN_PARAMGEN2,
FIPS_R_FIPS_SELFTEST_FAILED);
goto err;
}
if (!fips_check_dsa_prng(ret, L, N))
goto err;
#endif
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 (;;)
{
__fips_constseg
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
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