openssl/crypto/dsa/dsa_key.c
Bodo Möller bd31fb2145 Change to mitigate branch prediction attacks
Submitted by: Matthew D Wood
Reviewed by: Bodo Moeller
2007-03-28 00:15:28 +00:00

129 lines
4.4 KiB
C

/* crypto/dsa/dsa_key.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.]
*/
#include <stdio.h>
#include <time.h>
#include "cryptlib.h"
#ifndef OPENSSL_NO_SHA
#include <openssl/bn.h>
#include <openssl/dsa.h>
#include <openssl/rand.h>
static int dsa_builtin_keygen(DSA *dsa);
int DSA_generate_key(DSA *dsa)
{
if(dsa->meth->dsa_keygen)
return dsa->meth->dsa_keygen(dsa);
return dsa_builtin_keygen(dsa);
}
static int dsa_builtin_keygen(DSA *dsa)
{
int ok=0;
BN_CTX *ctx=NULL;
BIGNUM *pub_key=NULL,*priv_key=NULL;
if ((ctx=BN_CTX_new()) == NULL) goto err;
if (dsa->priv_key == NULL)
{
if ((priv_key=BN_new()) == NULL) goto err;
}
else
priv_key=dsa->priv_key;
do
if (!BN_rand_range(priv_key,dsa->q)) goto err;
while (BN_is_zero(priv_key));
if (dsa->pub_key == NULL)
{
if ((pub_key=BN_new()) == NULL) goto err;
}
else
pub_key=dsa->pub_key;
{
BIGNUM local_prk;
BIGNUM *prk;
if ((dsa->flags & DSA_FLAG_NO_EXP_CONSTTIME) == 0)
{
BN_init(&local_prk);
prk = &local_prk;
BN_with_flags(prk, priv_key, BN_FLG_CONSTTIME);
}
else
prk = priv_key;
if (!BN_mod_exp(pub_key,dsa->g,prk,dsa->p,ctx)) goto err;
}
dsa->priv_key=priv_key;
dsa->pub_key=pub_key;
ok=1;
err:
if ((pub_key != NULL) && (dsa->pub_key == NULL)) BN_free(pub_key);
if ((priv_key != NULL) && (dsa->priv_key == NULL)) BN_free(priv_key);
if (ctx != NULL) BN_CTX_free(ctx);
return(ok);
}
#endif