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openssl/crypto/dsa/dsa_ossl.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

447 lines
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/* crypto/dsa/dsa_ossl.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.]
*/
/* Original version from Steven Schoch <schoch@sheba.arc.nasa.gov> */
#include <stdio.h>
#include "cryptlib.h"
#include <openssl/bn.h>
#include <openssl/sha.h>
#include <openssl/dsa.h>
#include <openssl/rand.h>
#include <openssl/asn1.h>
static DSA_SIG *dsa_do_sign(const unsigned char *dgst, int dlen, DSA *dsa);
static int dsa_sign_setup_no_digest(DSA *dsa, BN_CTX *ctx_in, BIGNUM **kinvp,
BIGNUM **rp);
static int dsa_sign_setup(DSA *dsa, BN_CTX *ctx_in, BIGNUM **kinvp,
BIGNUM **rp, const unsigned char *dgst, int dlen);
static int dsa_do_verify(const unsigned char *dgst, int dgst_len,
DSA_SIG *sig, DSA *dsa);
static int dsa_init(DSA *dsa);
static int dsa_finish(DSA *dsa);
static DSA_METHOD openssl_dsa_meth = {
"OpenSSL DSA method",
dsa_do_sign,
dsa_sign_setup_no_digest,
dsa_do_verify,
NULL, /* dsa_mod_exp, */
NULL, /* dsa_bn_mod_exp, */
dsa_init,
dsa_finish,
DSA_FLAG_FIPS_METHOD,
NULL,
NULL,
NULL
};
/*-
* These macro wrappers replace attempts to use the dsa_mod_exp() and
* bn_mod_exp() handlers in the DSA_METHOD structure. We avoid the problem of
* having a the macro work as an expression by bundling an "err_instr". So;
*
* if (!dsa->meth->bn_mod_exp(dsa, r,dsa->g,&k,dsa->p,ctx,
* dsa->method_mont_p)) goto err;
*
* can be replaced by;
*
* DSA_BN_MOD_EXP(goto err, dsa, r, dsa->g, &k, dsa->p, ctx,
* dsa->method_mont_p);
*/
#define DSA_MOD_EXP(err_instr,dsa,rr,a1,p1,a2,p2,m,ctx,in_mont) \
do { \
int _tmp_res53; \
if((dsa)->meth->dsa_mod_exp) \
_tmp_res53 = (dsa)->meth->dsa_mod_exp((dsa), (rr), (a1), (p1), \
(a2), (p2), (m), (ctx), (in_mont)); \
else \
_tmp_res53 = BN_mod_exp2_mont((rr), (a1), (p1), (a2), (p2), \
(m), (ctx), (in_mont)); \
if(!_tmp_res53) err_instr; \
} while(0)
#define DSA_BN_MOD_EXP(err_instr,dsa,r,a,p,m,ctx,m_ctx) \
do { \
int _tmp_res53; \
if((dsa)->meth->bn_mod_exp) \
_tmp_res53 = (dsa)->meth->bn_mod_exp((dsa), (r), (a), (p), \
(m), (ctx), (m_ctx)); \
else \
_tmp_res53 = BN_mod_exp_mont((r), (a), (p), (m), (ctx), (m_ctx)); \
if(!_tmp_res53) err_instr; \
} while(0)
const DSA_METHOD *DSA_OpenSSL(void)
{
return &openssl_dsa_meth;
}
static DSA_SIG *dsa_do_sign(const unsigned char *dgst, int dlen, DSA *dsa)
{
BIGNUM *kinv = NULL, *r = NULL, *s = NULL;
BIGNUM *m;
BIGNUM *xr;
BN_CTX *ctx = NULL;
int reason = ERR_R_BN_LIB;
DSA_SIG *ret = NULL;
int noredo = 0;
m = BN_new();
xr = BN_new();
if (!m || !xr)
goto err;
if (!dsa->p || !dsa->q || !dsa->g) {
reason = DSA_R_MISSING_PARAMETERS;
goto err;
}
s = BN_new();
if (s == NULL)
goto err;
ctx = BN_CTX_new();
if (ctx == NULL)
goto err;
redo:
if ((dsa->kinv == NULL) || (dsa->r == NULL)) {
if (!dsa_sign_setup(dsa, ctx, &kinv, &r, dgst, dlen))
goto err;
} else {
kinv = dsa->kinv;
dsa->kinv = NULL;
r = dsa->r;
dsa->r = NULL;
noredo = 1;
}
if (dlen > BN_num_bytes(dsa->q))
/*
* if the digest length is greater than the size of q use the
* BN_num_bits(dsa->q) leftmost bits of the digest, see fips 186-3,
* 4.2
*/
dlen = BN_num_bytes(dsa->q);
if (BN_bin2bn(dgst, dlen, m) == NULL)
goto err;
/* Compute s = inv(k) (m + xr) mod q */
if (!BN_mod_mul(xr, dsa->priv_key, r, dsa->q, ctx))
goto err; /* s = xr */
if (!BN_add(s, xr, m))
goto err; /* s = m + xr */
if (BN_cmp(s, dsa->q) > 0)
if (!BN_sub(s, s, dsa->q))
goto err;
if (!BN_mod_mul(s, s, kinv, dsa->q, ctx))
goto err;
ret = DSA_SIG_new();
if (ret == NULL)
goto err;
/*
* Redo if r or s is zero as required by FIPS 186-3: this is very
* unlikely.
*/
if (BN_is_zero(r) || BN_is_zero(s)) {
if (noredo) {
reason = DSA_R_NEED_NEW_SETUP_VALUES;
goto err;
}
goto redo;
}
ret->r = r;
ret->s = s;
err:
if (!ret) {
DSAerr(DSA_F_DSA_DO_SIGN, reason);
BN_free(r);
BN_free(s);
}
if (ctx != NULL)
BN_CTX_free(ctx);
BN_clear_free(m);
BN_clear_free(xr);
if (kinv != NULL) /* dsa->kinv is NULL now if we used it */
BN_clear_free(kinv);
return (ret);
}
static int dsa_sign_setup_no_digest(DSA *dsa, BN_CTX *ctx_in,
BIGNUM **kinvp, BIGNUM **rp)
{
return dsa_sign_setup(dsa, ctx_in, kinvp, rp, NULL, 0);
}
static int dsa_sign_setup(DSA *dsa, BN_CTX *ctx_in,
BIGNUM **kinvp, BIGNUM **rp,
const unsigned char *dgst, int dlen)
{
BN_CTX *ctx = NULL;
BIGNUM *k, *kq, *K, *kinv = NULL, *r = NULL;
int ret = 0;
if (!dsa->p || !dsa->q || !dsa->g) {
DSAerr(DSA_F_DSA_SIGN_SETUP, DSA_R_MISSING_PARAMETERS);
return 0;
}
k = BN_new();
kq = BN_new();
if (!k || !kq)
goto err;
if (ctx_in == NULL) {
if ((ctx = BN_CTX_new()) == NULL)
goto err;
} else
ctx = ctx_in;
if ((r = BN_new()) == NULL)
goto err;
/* Get random k */
do {
if (dgst != NULL) {
/*
* We calculate k from SHA512(private_key + H(message) + random).
* This protects the private key from a weak PRNG.
*/
if (!BN_generate_dsa_nonce(k, dsa->q, dsa->priv_key, dgst,
dlen, ctx))
goto err;
} else if (!BN_rand_range(k, dsa->q))
goto err;
} while (BN_is_zero(k));
if ((dsa->flags & DSA_FLAG_NO_EXP_CONSTTIME) == 0) {
BN_set_flags(k, BN_FLG_CONSTTIME);
}
if (dsa->flags & DSA_FLAG_CACHE_MONT_P) {
if (!BN_MONT_CTX_set_locked(&dsa->method_mont_p,
CRYPTO_LOCK_DSA, dsa->p, ctx))
goto err;
}
/* Compute r = (g^k mod p) mod q */
if ((dsa->flags & DSA_FLAG_NO_EXP_CONSTTIME) == 0) {
if (!BN_copy(kq, k))
goto err;
/*
* We do not want timing information to leak the length of k, so we
* compute g^k using an equivalent exponent of fixed length. (This
* is a kludge that we need because the BN_mod_exp_mont() does not
* let us specify the desired timing behaviour.)
*/
if (!BN_add(kq, kq, dsa->q))
goto err;
if (BN_num_bits(kq) <= BN_num_bits(dsa->q)) {
if (!BN_add(kq, kq, dsa->q))
goto err;
}
K = kq;
} else {
K = k;
}
DSA_BN_MOD_EXP(goto err, dsa, r, dsa->g, K, dsa->p, ctx,
dsa->method_mont_p);
if (!BN_mod(r, r, dsa->q, ctx))
goto err;
/* Compute part of 's = inv(k) (m + xr) mod q' */
if ((kinv = BN_mod_inverse(NULL, k, dsa->q, ctx)) == NULL)
goto err;
if (*kinvp != NULL)
BN_clear_free(*kinvp);
*kinvp = kinv;
kinv = NULL;
if (*rp != NULL)
BN_clear_free(*rp);
*rp = r;
ret = 1;
err:
if (!ret) {
DSAerr(DSA_F_DSA_SIGN_SETUP, ERR_R_BN_LIB);
if (r != NULL)
BN_clear_free(r);
}
if (ctx_in == NULL)
BN_CTX_free(ctx);
BN_clear_free(k);
BN_clear_free(kq);
return (ret);
}
static int dsa_do_verify(const unsigned char *dgst, int dgst_len,
DSA_SIG *sig, DSA *dsa)
{
BN_CTX *ctx;
BIGNUM *u1, *u2, *t1;
BN_MONT_CTX *mont = NULL;
int ret = -1, i;
if (!dsa->p || !dsa->q || !dsa->g) {
DSAerr(DSA_F_DSA_DO_VERIFY, DSA_R_MISSING_PARAMETERS);
return -1;
}
i = BN_num_bits(dsa->q);
/* fips 186-3 allows only different sizes for q */
if (i != 160 && i != 224 && i != 256) {
DSAerr(DSA_F_DSA_DO_VERIFY, DSA_R_BAD_Q_VALUE);
return -1;
}
if (BN_num_bits(dsa->p) > OPENSSL_DSA_MAX_MODULUS_BITS) {
DSAerr(DSA_F_DSA_DO_VERIFY, DSA_R_MODULUS_TOO_LARGE);
return -1;
}
u1 = BN_new();
u2 = BN_new();
t1 = BN_new();
ctx = BN_CTX_new();
if (!u1 || !u2 || !t1 || !ctx)
goto err;
if (BN_is_zero(sig->r) || BN_is_negative(sig->r) ||
BN_ucmp(sig->r, dsa->q) >= 0) {
ret = 0;
goto err;
}
if (BN_is_zero(sig->s) || BN_is_negative(sig->s) ||
BN_ucmp(sig->s, dsa->q) >= 0) {
ret = 0;
goto err;
}
/*
* Calculate W = inv(S) mod Q save W in u2
*/
if ((BN_mod_inverse(u2, sig->s, dsa->q, ctx)) == NULL)
goto err;
/* save M in u1 */
if (dgst_len > (i >> 3))
/*
* if the digest length is greater than the size of q use the
* BN_num_bits(dsa->q) leftmost bits of the digest, see fips 186-3,
* 4.2
*/
dgst_len = (i >> 3);
if (BN_bin2bn(dgst, dgst_len, u1) == NULL)
goto err;
/* u1 = M * w mod q */
if (!BN_mod_mul(u1, u1, u2, dsa->q, ctx))
goto err;
/* u2 = r * w mod q */
if (!BN_mod_mul(u2, sig->r, u2, dsa->q, ctx))
goto err;
if (dsa->flags & DSA_FLAG_CACHE_MONT_P) {
mont = BN_MONT_CTX_set_locked(&dsa->method_mont_p,
CRYPTO_LOCK_DSA, dsa->p, ctx);
if (!mont)
goto err;
}
DSA_MOD_EXP(goto err, dsa, t1, dsa->g, u1, dsa->pub_key, u2, dsa->p, ctx,
mont);
/* BN_copy(&u1,&t1); */
/* let u1 = u1 mod q */
if (!BN_mod(u1, t1, dsa->q, ctx))
goto err;
/*
* V is now in u1. If the signature is correct, it will be equal to R.
*/
ret = (BN_ucmp(u1, sig->r) == 0);
err:
if (ret < 0)
DSAerr(DSA_F_DSA_DO_VERIFY, ERR_R_BN_LIB);
if (ctx != NULL)
BN_CTX_free(ctx);
if (u1)
BN_free(u1);
if (u2)
BN_free(u2);
if (t1)
BN_free(t1);
return (ret);
}
static int dsa_init(DSA *dsa)
{
dsa->flags |= DSA_FLAG_CACHE_MONT_P;
return (1);
}
static int dsa_finish(DSA *dsa)
{
if (dsa->method_mont_p)
BN_MONT_CTX_free(dsa->method_mont_p);
return (1);
}
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