2191b3ba44
Submitted by: Alexei Khlebnikov <alexei.khlebnikov@opera.com> Reviewed by: steve OOM checking. Leak in OOM fix. Fall-through comment. Duplicate code elimination.
312 lines
9.9 KiB
C
312 lines
9.9 KiB
C
/* crypto/bn/bn_exp2.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.]
|
|
*/
|
|
/* ====================================================================
|
|
* Copyright (c) 1998-2000 The OpenSSL Project. All rights reserved.
|
|
*
|
|
* 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 above 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 acknowledgment:
|
|
* "This product includes software developed by the OpenSSL Project
|
|
* for use in the OpenSSL Toolkit. (http://www.openssl.org/)"
|
|
*
|
|
* 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
|
|
* endorse or promote products derived from this software without
|
|
* prior written permission. For written permission, please contact
|
|
* openssl-core@openssl.org.
|
|
*
|
|
* 5. Products derived from this software may not be called "OpenSSL"
|
|
* nor may "OpenSSL" appear in their names without prior written
|
|
* permission of the OpenSSL Project.
|
|
*
|
|
* 6. Redistributions of any form whatsoever must retain the following
|
|
* acknowledgment:
|
|
* "This product includes software developed by the OpenSSL Project
|
|
* for use in the OpenSSL Toolkit (http://www.openssl.org/)"
|
|
*
|
|
* THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
|
|
* EXPRESSED 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 OpenSSL PROJECT OR
|
|
* ITS 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.
|
|
* ====================================================================
|
|
*
|
|
* This product includes cryptographic software written by Eric Young
|
|
* (eay@cryptsoft.com). This product includes software written by Tim
|
|
* Hudson (tjh@cryptsoft.com).
|
|
*
|
|
*/
|
|
|
|
#include <stdio.h>
|
|
#include "cryptlib.h"
|
|
#include "bn_lcl.h"
|
|
|
|
#define TABLE_SIZE 32
|
|
|
|
int BN_mod_exp2_mont(BIGNUM *rr, const BIGNUM *a1, const BIGNUM *p1,
|
|
const BIGNUM *a2, const BIGNUM *p2, const BIGNUM *m,
|
|
BN_CTX *ctx, BN_MONT_CTX *in_mont)
|
|
{
|
|
int i,j,bits,b,bits1,bits2,ret=0,wpos1,wpos2,window1,window2,wvalue1,wvalue2;
|
|
int r_is_one=1;
|
|
BIGNUM *d,*r;
|
|
const BIGNUM *a_mod_m;
|
|
/* Tables of variables obtained from 'ctx' */
|
|
BIGNUM *val1[TABLE_SIZE], *val2[TABLE_SIZE];
|
|
BN_MONT_CTX *mont=NULL;
|
|
|
|
bn_check_top(a1);
|
|
bn_check_top(p1);
|
|
bn_check_top(a2);
|
|
bn_check_top(p2);
|
|
bn_check_top(m);
|
|
|
|
if (!(m->d[0] & 1))
|
|
{
|
|
BNerr(BN_F_BN_MOD_EXP2_MONT,BN_R_CALLED_WITH_EVEN_MODULUS);
|
|
return(0);
|
|
}
|
|
bits1=BN_num_bits(p1);
|
|
bits2=BN_num_bits(p2);
|
|
if ((bits1 == 0) && (bits2 == 0))
|
|
{
|
|
ret = BN_one(rr);
|
|
return ret;
|
|
}
|
|
|
|
bits=(bits1 > bits2)?bits1:bits2;
|
|
|
|
BN_CTX_start(ctx);
|
|
d = BN_CTX_get(ctx);
|
|
r = BN_CTX_get(ctx);
|
|
val1[0] = BN_CTX_get(ctx);
|
|
val2[0] = BN_CTX_get(ctx);
|
|
if(!d || !r || !val1[0] || !val2[0]) goto err;
|
|
|
|
if (in_mont != NULL)
|
|
mont=in_mont;
|
|
else
|
|
{
|
|
if ((mont=BN_MONT_CTX_new()) == NULL) goto err;
|
|
if (!BN_MONT_CTX_set(mont,m,ctx)) goto err;
|
|
}
|
|
|
|
window1 = BN_window_bits_for_exponent_size(bits1);
|
|
window2 = BN_window_bits_for_exponent_size(bits2);
|
|
|
|
/*
|
|
* Build table for a1: val1[i] := a1^(2*i + 1) mod m for i = 0 .. 2^(window1-1)
|
|
*/
|
|
if (a1->neg || BN_ucmp(a1,m) >= 0)
|
|
{
|
|
if (!BN_mod(val1[0],a1,m,ctx))
|
|
goto err;
|
|
a_mod_m = val1[0];
|
|
}
|
|
else
|
|
a_mod_m = a1;
|
|
if (BN_is_zero(a_mod_m))
|
|
{
|
|
BN_zero(rr);
|
|
ret = 1;
|
|
goto err;
|
|
}
|
|
|
|
if (!BN_to_montgomery(val1[0],a_mod_m,mont,ctx)) goto err;
|
|
if (window1 > 1)
|
|
{
|
|
if (!BN_mod_mul_montgomery(d,val1[0],val1[0],mont,ctx)) goto err;
|
|
|
|
j=1<<(window1-1);
|
|
for (i=1; i<j; i++)
|
|
{
|
|
if(((val1[i] = BN_CTX_get(ctx)) == NULL) ||
|
|
!BN_mod_mul_montgomery(val1[i],val1[i-1],
|
|
d,mont,ctx))
|
|
goto err;
|
|
}
|
|
}
|
|
|
|
|
|
/*
|
|
* Build table for a2: val2[i] := a2^(2*i + 1) mod m for i = 0 .. 2^(window2-1)
|
|
*/
|
|
if (a2->neg || BN_ucmp(a2,m) >= 0)
|
|
{
|
|
if (!BN_mod(val2[0],a2,m,ctx))
|
|
goto err;
|
|
a_mod_m = val2[0];
|
|
}
|
|
else
|
|
a_mod_m = a2;
|
|
if (BN_is_zero(a_mod_m))
|
|
{
|
|
BN_zero(rr);
|
|
ret = 1;
|
|
goto err;
|
|
}
|
|
if (!BN_to_montgomery(val2[0],a_mod_m,mont,ctx)) goto err;
|
|
if (window2 > 1)
|
|
{
|
|
if (!BN_mod_mul_montgomery(d,val2[0],val2[0],mont,ctx)) goto err;
|
|
|
|
j=1<<(window2-1);
|
|
for (i=1; i<j; i++)
|
|
{
|
|
if(((val2[i] = BN_CTX_get(ctx)) == NULL) ||
|
|
!BN_mod_mul_montgomery(val2[i],val2[i-1],
|
|
d,mont,ctx))
|
|
goto err;
|
|
}
|
|
}
|
|
|
|
|
|
/* Now compute the power product, using independent windows. */
|
|
r_is_one=1;
|
|
wvalue1=0; /* The 'value' of the first window */
|
|
wvalue2=0; /* The 'value' of the second window */
|
|
wpos1=0; /* If wvalue1 > 0, the bottom bit of the first window */
|
|
wpos2=0; /* If wvalue2 > 0, the bottom bit of the second window */
|
|
|
|
if (!BN_to_montgomery(r,BN_value_one(),mont,ctx)) goto err;
|
|
for (b=bits-1; b>=0; b--)
|
|
{
|
|
if (!r_is_one)
|
|
{
|
|
if (!BN_mod_mul_montgomery(r,r,r,mont,ctx))
|
|
goto err;
|
|
}
|
|
|
|
if (!wvalue1)
|
|
if (BN_is_bit_set(p1, b))
|
|
{
|
|
/* consider bits b-window1+1 .. b for this window */
|
|
i = b-window1+1;
|
|
while (!BN_is_bit_set(p1, i)) /* works for i<0 */
|
|
i++;
|
|
wpos1 = i;
|
|
wvalue1 = 1;
|
|
for (i = b-1; i >= wpos1; i--)
|
|
{
|
|
wvalue1 <<= 1;
|
|
if (BN_is_bit_set(p1, i))
|
|
wvalue1++;
|
|
}
|
|
}
|
|
|
|
if (!wvalue2)
|
|
if (BN_is_bit_set(p2, b))
|
|
{
|
|
/* consider bits b-window2+1 .. b for this window */
|
|
i = b-window2+1;
|
|
while (!BN_is_bit_set(p2, i))
|
|
i++;
|
|
wpos2 = i;
|
|
wvalue2 = 1;
|
|
for (i = b-1; i >= wpos2; i--)
|
|
{
|
|
wvalue2 <<= 1;
|
|
if (BN_is_bit_set(p2, i))
|
|
wvalue2++;
|
|
}
|
|
}
|
|
|
|
if (wvalue1 && b == wpos1)
|
|
{
|
|
/* wvalue1 is odd and < 2^window1 */
|
|
if (!BN_mod_mul_montgomery(r,r,val1[wvalue1>>1],mont,ctx))
|
|
goto err;
|
|
wvalue1 = 0;
|
|
r_is_one = 0;
|
|
}
|
|
|
|
if (wvalue2 && b == wpos2)
|
|
{
|
|
/* wvalue2 is odd and < 2^window2 */
|
|
if (!BN_mod_mul_montgomery(r,r,val2[wvalue2>>1],mont,ctx))
|
|
goto err;
|
|
wvalue2 = 0;
|
|
r_is_one = 0;
|
|
}
|
|
}
|
|
if (!BN_from_montgomery(rr,r,mont,ctx))
|
|
goto err;
|
|
ret=1;
|
|
err:
|
|
if ((in_mont == NULL) && (mont != NULL)) BN_MONT_CTX_free(mont);
|
|
BN_CTX_end(ctx);
|
|
bn_check_top(rr);
|
|
return(ret);
|
|
}
|