/* 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) 1998-2006 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 <openssl/bn.h>
#include <string.h>
#include <openssl/mem.h>
#include <openssl/thread.h>
#include "internal.h"
#include "../internal.h"
#if !defined(OPENSSL_NO_ASM) && \
(defined(OPENSSL_X86) || defined(OPENSSL_X86_64))
#define OPENSSL_BN_ASM_MONT
#endif
BN_MONT_CTX *BN_MONT_CTX_new(void) {
BN_MONT_CTX *ret = OPENSSL_malloc(sizeof(BN_MONT_CTX));
if (ret == NULL) {
return NULL;
}
BN_MONT_CTX_init(ret);
ret->flags = BN_FLG_MALLOCED;
return ret;
}
void BN_MONT_CTX_init(BN_MONT_CTX *mont) {
memset(mont, 0, sizeof(BN_MONT_CTX));
BN_init(&mont->RR);
BN_init(&mont->N);
BN_init(&mont->Ni);
}
void BN_MONT_CTX_free(BN_MONT_CTX *mont) {
if (mont == NULL) {
return;
}
BN_free(&mont->RR);
BN_free(&mont->N);
BN_free(&mont->Ni);
if (mont->flags & BN_FLG_MALLOCED) {
OPENSSL_free(mont);
}
}
BN_MONT_CTX *BN_MONT_CTX_copy(BN_MONT_CTX *to, BN_MONT_CTX *from) {
if (to == from) {
return to;
}
if (!BN_copy(&to->RR, &from->RR) ||
!BN_copy(&to->N, &from->N) ||
!BN_copy(&to->Ni, &from->Ni)) {
return NULL;
}
to->ri = from->ri;
to->n0[0] = from->n0[0];
to->n0[1] = from->n0[1];
return to;
}
int BN_MONT_CTX_set(BN_MONT_CTX *mont, const BIGNUM *mod, BN_CTX *ctx) {
int ret = 0;
BIGNUM *Ri, *R;
BIGNUM tmod;
BN_ULONG buf[2];
BN_CTX_start(ctx);
Ri = BN_CTX_get(ctx);
if (Ri == NULL) {
goto err;
}
R = &mont->RR; /* grab RR as a temp */
if (!BN_copy(&mont->N, mod)) {
goto err; /* Set N */
}
mont->N.neg = 0;
BN_init(&tmod);
tmod.d = buf;
tmod.dmax = 2;
tmod.neg = 0;
mont->ri = (BN_num_bits(mod) + (BN_BITS2 - 1)) / BN_BITS2 * BN_BITS2;
#if defined(OPENSSL_BN_ASM_MONT) && (BN_BITS2 <= 32)
/* Only certain BN_BITS2<=32 platforms actually make use of
* n0[1], and we could use the #else case (with a shorter R
* value) for the others. However, currently only the assembler
* files do know which is which. */
BN_zero(R);
if (!BN_set_bit(R, 2 * BN_BITS2)) {
goto err;
}
tmod.top = 0;
if ((buf[0] = mod->d[0])) {
tmod.top = 1;
}
if ((buf[1] = mod->top > 1 ? mod->d[1] : 0)) {
tmod.top = 2;
}
if (BN_mod_inverse(Ri, R, &tmod, ctx) == NULL) {
goto err;
}
if (!BN_lshift(Ri, Ri, 2 * BN_BITS2)) {
goto err; /* R*Ri */
}
if (!BN_is_zero(Ri)) {
if (!BN_sub_word(Ri, 1)) {
goto err;
}
} else {
/* if N mod word size == 1 */
if (bn_expand(Ri, (int)sizeof(BN_ULONG) * 2) == NULL) {
goto err;
}
/* Ri-- (mod double word size) */
Ri->neg = 0;
Ri->d[0] = BN_MASK2;
Ri->d[1] = BN_MASK2;
Ri->top = 2;
}
if (!BN_div(Ri, NULL, Ri, &tmod, ctx)) {
goto err;
}
/* Ni = (R*Ri-1)/N,
* keep only couple of least significant words: */
mont->n0[0] = (Ri->top > 0) ? Ri->d[0] : 0;
mont->n0[1] = (Ri->top > 1) ? Ri->d[1] : 0;
#else
BN_zero(R);
if (!BN_set_bit(R, BN_BITS2)) {
goto err; /* R */
}
buf[0] = mod->d[0]; /* tmod = N mod word size */
buf[1] = 0;
tmod.top = buf[0] != 0 ? 1 : 0;
/* Ri = R^-1 mod N*/
if (BN_mod_inverse(Ri, R, &tmod, ctx) == NULL) {
goto err;
}
if (!BN_lshift(Ri, Ri, BN_BITS2)) {
goto err; /* R*Ri */
}
if (!BN_is_zero(Ri)) {
if (!BN_sub_word(Ri, 1)) {
goto err;
}
} else {
/* if N mod word size == 1 */
if (!BN_set_word(Ri, BN_MASK2)) {
goto err; /* Ri-- (mod word size) */
}
}
if (!BN_div(Ri, NULL, Ri, &tmod, ctx)) {
goto err;
}
/* Ni = (R*Ri-1)/N,
* keep only least significant word: */
mont->n0[0] = (Ri->top > 0) ? Ri->d[0] : 0;
mont->n0[1] = 0;
#endif
/* setup RR for conversions */
BN_zero(&(mont->RR));
if (!BN_set_bit(&(mont->RR), mont->ri * 2)) {
goto err;
}
if (!BN_mod(&(mont->RR), &(mont->RR), &(mont->N), ctx)) {
goto err;
}
ret = 1;
err:
BN_CTX_end(ctx);
return ret;
}
BN_MONT_CTX *BN_MONT_CTX_set_locked(BN_MONT_CTX **pmont, CRYPTO_MUTEX *lock,
const BIGNUM *mod, BN_CTX *bn_ctx) {
CRYPTO_MUTEX_lock_read(lock);
BN_MONT_CTX *ctx = *pmont;
CRYPTO_MUTEX_unlock(lock);
if (ctx) {
return ctx;
}
CRYPTO_MUTEX_lock_write(lock);
ctx = *pmont;
if (ctx) {
goto out;
}
ctx = BN_MONT_CTX_new();
if (ctx == NULL) {
goto out;
}
if (!BN_MONT_CTX_set(ctx, mod, bn_ctx)) {
BN_MONT_CTX_free(ctx);
ctx = NULL;
goto out;
}
*pmont = ctx;
out:
CRYPTO_MUTEX_unlock(lock);
return ctx;
}
int BN_to_montgomery(BIGNUM *ret, const BIGNUM *a, const BN_MONT_CTX *mont,
BN_CTX *ctx) {
return BN_mod_mul_montgomery(ret, a, &mont->RR, mont, ctx);
}
#if 0
static int BN_from_montgomery_word(BIGNUM *ret, BIGNUM *r,
const BN_MONT_CTX *mont) {
const BIGNUM *n;
BN_ULONG *ap, *np, *rp, n0, v, carry;
int nl, max, i;
n = &mont->N;
nl = n->top;
if (nl == 0) {
ret->top = 0;
return 1;
}
max = (2 * nl); /* carry is stored separately */
if (bn_wexpand(r, max) == NULL) {
return 0;
}
r->neg ^= n->neg;
np = n->d;
rp = r->d;
/* clear the top words of T */
if (max > r->top) {
memset(&rp[r->top], 0, (max - r->top) * sizeof(BN_ULONG));
}
r->top = max;
n0 = mont->n0[0];
for (carry = 0, i = 0; i < nl; i++, rp++) {
v = bn_mul_add_words(rp, np, nl, (rp[0] * n0) & BN_MASK2);
v = (v + carry + rp[nl]) & BN_MASK2;
carry |= (v != rp[nl]);
carry &= (v <= rp[nl]);
rp[nl] = v;
}
if (bn_wexpand(ret, nl) == NULL) {
return 0;
}
ret->top = nl;
ret->neg = r->neg;
rp = ret->d;
ap = &(r->d[nl]);
{
BN_ULONG *nrp;
size_t m;
v = bn_sub_words(rp, ap, np, nl) - carry;
/* if subtraction result is real, then trick unconditional memcpy below to
* perform in-place "refresh" instead of actual copy. */
m = (0 - (size_t)v);
nrp = (BN_ULONG *)(((intptr_t)rp & ~m) | ((intptr_t)ap & m));
for (i = 0, nl -= 4; i < nl; i += 4) {
BN_ULONG t1, t2, t3, t4;
t1 = nrp[i + 0];
t2 = nrp[i + 1];
t3 = nrp[i + 2];
ap[i + 0] = 0;
t4 = nrp[i + 3];
ap[i + 1] = 0;
rp[i + 0] = t1;
ap[i + 2] = 0;
rp[i + 1] = t2;
ap[i + 3] = 0;
rp[i + 2] = t3;
rp[i + 3] = t4;
}
for (nl += 4; i < nl; i++) {
rp[i] = nrp[i], ap[i] = 0;
}
}
bn_correct_top(r);
bn_correct_top(ret);
return 1;
}
#endif
#define PTR_SIZE_INT size_t
static int BN_from_montgomery_word(BIGNUM *ret, BIGNUM *r, const BN_MONT_CTX *mont)
{
BIGNUM *n;
BN_ULONG *ap,*np,*rp,n0,v,carry;
int nl,max,i;
n= (BIGNUM*) &(mont->N);
nl=n->top;
if (nl == 0) { ret->top=0; return(1); }
max=(2*nl); /* carry is stored separately */
if (bn_wexpand(r,max) == NULL) return(0);
r->neg^=n->neg;
np=n->d;
rp=r->d;
/* clear the top words of T */
#if 1
for (i=r->top; i<max; i++) /* memset? XXX */
rp[i]=0;
#else
memset(&(rp[r->top]),0,(max-r->top)*sizeof(BN_ULONG));
#endif
r->top=max;
n0=mont->n0[0];
for (carry=0, i=0; i<nl; i++, rp++)
{
v=bn_mul_add_words(rp,np,nl,(rp[0]*n0)&BN_MASK2);
v = (v+carry+rp[nl])&BN_MASK2;
carry |= (v != rp[nl]);
carry &= (v <= rp[nl]);
rp[nl]=v;
}
if (bn_wexpand(ret,nl) == NULL) return(0);
ret->top=nl;
ret->neg=r->neg;
rp=ret->d;
ap=&(r->d[nl]);
{
BN_ULONG *nrp;
size_t m;
v=bn_sub_words(rp,ap,np,nl)-carry;
/* if subtraction result is real, then
* trick unconditional memcpy below to perform in-place
* "refresh" instead of actual copy. */
m=(0-(size_t)v);
nrp=(BN_ULONG *)(((PTR_SIZE_INT)rp&~m)|((PTR_SIZE_INT)ap&m));
for (i=0,nl-=4; i<nl; i+=4)
{
BN_ULONG t1,t2,t3,t4;
t1=nrp[i+0];
t2=nrp[i+1];
t3=nrp[i+2]; ap[i+0]=0;
t4=nrp[i+3]; ap[i+1]=0;
rp[i+0]=t1; ap[i+2]=0;
rp[i+1]=t2; ap[i+3]=0;
rp[i+2]=t3;
rp[i+3]=t4;
}
for (nl+=4; i<nl; i++)
rp[i]=nrp[i], ap[i]=0;
}
bn_correct_top(r);
bn_correct_top(ret);
return(1);
}
int BN_from_montgomery(BIGNUM *ret, const BIGNUM *a, const BN_MONT_CTX *mont,
BN_CTX *ctx) {
int retn = 0;
BIGNUM *t;
BN_CTX_start(ctx);
t = BN_CTX_get(ctx);
if (t == NULL) {
return 0;
}
if (BN_copy(t, a)) {
retn = BN_from_montgomery_word(ret, t, mont);
}
BN_CTX_end(ctx);
return retn;
}
int BN_mod_mul_montgomery(BIGNUM *r, const BIGNUM *a, const BIGNUM *b,
const BN_MONT_CTX *mont, BN_CTX *ctx) {
BIGNUM *tmp;
int ret = 0;
#if defined(OPENSSL_BN_ASM_MONT)
int num = mont->N.top;
if (num > 1 && a->top == num && b->top == num) {
if (bn_wexpand(r, num) == NULL) {
return 0;
}
if (bn_mul_mont(r->d, a->d, b->d, mont->N.d, mont->n0, num)) {
r->neg = a->neg ^ b->neg;
r->top = num;
bn_correct_top(r);
return 1;
}
}
#endif
BN_CTX_start(ctx);
tmp = BN_CTX_get(ctx);
if (tmp == NULL) {
goto err;
}
if (a == b) {
if (!BN_sqr(tmp, a, ctx)) {
goto err;
}
} else {
if (!BN_mul(tmp, a, b, ctx)) {
goto err;
}
}
/* reduce from aRR to aR */
if (!BN_from_montgomery_word(r, tmp, mont)) {
goto err;
}
ret = 1;
err:
BN_CTX_end(ctx);
return ret;
}
