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boringssl/crypto/bn/montgomery.c

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Inital import. Initial fork from f2d678e6e89b6508147086610e985d4e8416e867 (1.0.2 beta). (This change contains substantial changes from the original and effectively starts a new history.)
2014-06-20 20:00:00 +01:00
/* 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>
Remove string.h from base.h. Including string.h in base.h causes any file that includes a BoringSSL header to include string.h. Generally this wouldn't be a problem, although string.h might slow down the compile if it wasn't otherwise needed. However, it also causes problems for ipsec-tools in Android because OpenSSL didn't have this behaviour. This change removes string.h from base.h and, instead, adds it to each .c file that requires it. Change-Id: I5968e50b0e230fd3adf9b72dd2836e6f52d6fb37 Reviewed-on: https://boringssl-review.googlesource.com/3200 Reviewed-by: David Benjamin <davidben@chromium.org> Reviewed-by: Adam Langley <agl@google.com>
2015-01-31 01:08:37 +00:00
#include <string.h>
Check for 0 modulus in BN_MONT_CTX_set. The function BN_MONT_CTX_set was assuming that the modulus was non-zero and therefore that |mod->top| > 0. In an error situation that may not be the case and could cause a seg fault. This is a follow on from CVE-2015-1794. (Imported from upstream's 512368c9ed4d53fb230000e83071eb81bf628b22.) The CVE itself doesn't affect us as the bit strength check in the DHE logic excludes zero. Also add tests to bn_test for a couple of division by zero cases. (This and BN_div.) Change-Id: Ibd8ef98d6be48eb95110021c23cd8e278656764d Reviewed-on: https://boringssl-review.googlesource.com/5690 Reviewed-by: Adam Langley <agl@google.com>
2015-08-11 22:10:55 +01:00
#include <openssl/err.h>
Inital import. Initial fork from f2d678e6e89b6508147086610e985d4e8416e867 (1.0.2 beta). (This change contains substantial changes from the original and effectively starts a new history.)
2014-06-20 20:00:00 +01:00
#include <openssl/mem.h>
#include <openssl/thread.h>
#include "internal.h"
Convert BN_MONT_CTX to new-style locking. This introduces a per-RSA/DSA/DH lock. This is good for lock contention, although pthread locks are depressingly bloated. Change-Id: I07c4d1606fc35135fc141ebe6ba904a28c8f8a0c Reviewed-on: https://boringssl-review.googlesource.com/4324 Reviewed-by: Adam Langley <agl@google.com>
2015-04-13 19:04:14 +01:00
#include "../internal.h"
Inital import. Initial fork from f2d678e6e89b6508147086610e985d4e8416e867 (1.0.2 beta). (This change contains substantial changes from the original and effectively starts a new history.)
2014-06-20 20:00:00 +01:00
#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;
}
Remove BN_MONT_CTX_init. One less exported function. Nothing ever stack-allocates them, within BoringSSL or in consumers. This avoids the slightly odd mechanism where BN_MONT_CTX_free might or might not free the BN_MONT_CTX itself based on a flag. (This is also consistent with OpenSSL 1.1.x which does away with the _init variants of both this and BIGNUM so it shouldn't be a compatibility concern long-term either.) Change-Id: Id885ae35a26f75686cc68a8aa971e2ea6767ba88 Reviewed-on: https://boringssl-review.googlesource.com/6350 Reviewed-by: Adam Langley <alangley@gmail.com>
2015-10-26 15:31:51 +00:00
memset(ret, 0, sizeof(BN_MONT_CTX));
BN_init(&ret->RR);
BN_init(&ret->N);
BN_init(&ret->Ni);
Inital import. Initial fork from f2d678e6e89b6508147086610e985d4e8416e867 (1.0.2 beta). (This change contains substantial changes from the original and effectively starts a new history.)
2014-06-20 20:00:00 +01:00
Remove BN_MONT_CTX_init. One less exported function. Nothing ever stack-allocates them, within BoringSSL or in consumers. This avoids the slightly odd mechanism where BN_MONT_CTX_free might or might not free the BN_MONT_CTX itself based on a flag. (This is also consistent with OpenSSL 1.1.x which does away with the _init variants of both this and BIGNUM so it shouldn't be a compatibility concern long-term either.) Change-Id: Id885ae35a26f75686cc68a8aa971e2ea6767ba88 Reviewed-on: https://boringssl-review.googlesource.com/6350 Reviewed-by: Adam Langley <alangley@gmail.com>
2015-10-26 15:31:51 +00:00
return ret;
Inital import. Initial fork from f2d678e6e89b6508147086610e985d4e8416e867 (1.0.2 beta). (This change contains substantial changes from the original and effectively starts a new history.)
2014-06-20 20:00:00 +01:00
}
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);
Remove BN_MONT_CTX_init. One less exported function. Nothing ever stack-allocates them, within BoringSSL or in consumers. This avoids the slightly odd mechanism where BN_MONT_CTX_free might or might not free the BN_MONT_CTX itself based on a flag. (This is also consistent with OpenSSL 1.1.x which does away with the _init variants of both this and BIGNUM so it shouldn't be a compatibility concern long-term either.) Change-Id: Id885ae35a26f75686cc68a8aa971e2ea6767ba88 Reviewed-on: https://boringssl-review.googlesource.com/6350 Reviewed-by: Adam Langley <alangley@gmail.com>
2015-10-26 15:31:51 +00:00
OPENSSL_free(mont);
Inital import. Initial fork from f2d678e6e89b6508147086610e985d4e8416e867 (1.0.2 beta). (This change contains substantial changes from the original and effectively starts a new history.)
2014-06-20 20:00:00 +01:00
}
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];
Check for 0 modulus in BN_MONT_CTX_set. The function BN_MONT_CTX_set was assuming that the modulus was non-zero and therefore that |mod->top| > 0. In an error situation that may not be the case and could cause a seg fault. This is a follow on from CVE-2015-1794. (Imported from upstream's 512368c9ed4d53fb230000e83071eb81bf628b22.) The CVE itself doesn't affect us as the bit strength check in the DHE logic excludes zero. Also add tests to bn_test for a couple of division by zero cases. (This and BN_div.) Change-Id: Ibd8ef98d6be48eb95110021c23cd8e278656764d Reviewed-on: https://boringssl-review.googlesource.com/5690 Reviewed-by: Adam Langley <agl@google.com>
2015-08-11 22:10:55 +01:00
if (BN_is_zero(mod)) {
OPENSSL_PUT_ERROR(BN, BN_R_DIV_BY_ZERO);
return 0;
}
Inital import. Initial fork from f2d678e6e89b6508147086610e985d4e8416e867 (1.0.2 beta). (This change contains substantial changes from the original and effectively starts a new history.)
2014-06-20 20:00:00 +01:00
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;
}
Convert BN_MONT_CTX to new-style locking. This introduces a per-RSA/DSA/DH lock. This is good for lock contention, although pthread locks are depressingly bloated. Change-Id: I07c4d1606fc35135fc141ebe6ba904a28c8f8a0c Reviewed-on: https://boringssl-review.googlesource.com/4324 Reviewed-by: Adam Langley <agl@google.com>
2015-04-13 19:04:14 +01:00
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);
Inital import. Initial fork from f2d678e6e89b6508147086610e985d4e8416e867 (1.0.2 beta). (This change contains substantial changes from the original and effectively starts a new history.)
2014-06-20 20:00:00 +01:00
Convert BN_MONT_CTX to new-style locking. This introduces a per-RSA/DSA/DH lock. This is good for lock contention, although pthread locks are depressingly bloated. Change-Id: I07c4d1606fc35135fc141ebe6ba904a28c8f8a0c Reviewed-on: https://boringssl-review.googlesource.com/4324 Reviewed-by: Adam Langley <agl@google.com>
2015-04-13 19:04:14 +01:00
if (ctx) {
return ctx;
Inital import. Initial fork from f2d678e6e89b6508147086610e985d4e8416e867 (1.0.2 beta). (This change contains substantial changes from the original and effectively starts a new history.)
2014-06-20 20:00:00 +01:00
}
Convert BN_MONT_CTX to new-style locking. This introduces a per-RSA/DSA/DH lock. This is good for lock contention, although pthread locks are depressingly bloated. Change-Id: I07c4d1606fc35135fc141ebe6ba904a28c8f8a0c Reviewed-on: https://boringssl-review.googlesource.com/4324 Reviewed-by: Adam Langley <agl@google.com>
2015-04-13 19:04:14 +01:00
CRYPTO_MUTEX_lock_write(lock);
ctx = *pmont;
if (ctx) {
goto out;
bignum: allow concurrent BN_MONT_CTX_set_locked() The lazy-initialisation of BN_MONT_CTX was serialising all threads, as noted by Daniel Sands and co at Sandia. This was to handle the case that 2 or more threads race to lazy-init the same context, but stunted all scalability in the case where 2 or more threads are doing unrelated things! We favour the latter case by punishing the former. The init work gets done by each thread that finds the context to be uninitialised, and we then lock the "set" logic after that work is done - the winning thread's work gets used, the losing threads throw away what they've done. (Imported from upstream's bf43446835bfd3f9abf1898a99ae20f2285320f3)
2014-06-20 20:00:00 +01:00
}
Inital import. Initial fork from f2d678e6e89b6508147086610e985d4e8416e867 (1.0.2 beta). (This change contains substantial changes from the original and effectively starts a new history.)
2014-06-20 20:00:00 +01:00
Convert BN_MONT_CTX to new-style locking. This introduces a per-RSA/DSA/DH lock. This is good for lock contention, although pthread locks are depressingly bloated. Change-Id: I07c4d1606fc35135fc141ebe6ba904a28c8f8a0c Reviewed-on: https://boringssl-review.googlesource.com/4324 Reviewed-by: Adam Langley <agl@google.com>
2015-04-13 19:04:14 +01:00
ctx = BN_MONT_CTX_new();
if (ctx == NULL) {
goto out;
Inital import. Initial fork from f2d678e6e89b6508147086610e985d4e8416e867 (1.0.2 beta). (This change contains substantial changes from the original and effectively starts a new history.)
2014-06-20 20:00:00 +01:00
}
Convert BN_MONT_CTX to new-style locking. This introduces a per-RSA/DSA/DH lock. This is good for lock contention, although pthread locks are depressingly bloated. Change-Id: I07c4d1606fc35135fc141ebe6ba904a28c8f8a0c Reviewed-on: https://boringssl-review.googlesource.com/4324 Reviewed-by: Adam Langley <agl@google.com>
2015-04-13 19:04:14 +01:00
if (!BN_MONT_CTX_set(ctx, mod, bn_ctx)) {
BN_MONT_CTX_free(ctx);
ctx = NULL;
goto out;
}
*pmont = ctx;
Inital import. Initial fork from f2d678e6e89b6508147086610e985d4e8416e867 (1.0.2 beta). (This change contains substantial changes from the original and effectively starts a new history.)
2014-06-20 20:00:00 +01:00
Convert BN_MONT_CTX to new-style locking. This introduces a per-RSA/DSA/DH lock. This is good for lock contention, although pthread locks are depressingly bloated. Change-Id: I07c4d1606fc35135fc141ebe6ba904a28c8f8a0c Reviewed-on: https://boringssl-review.googlesource.com/4324 Reviewed-by: Adam Langley <agl@google.com>
2015-04-13 19:04:14 +01:00
out:
CRYPTO_MUTEX_unlock(lock);
return ctx;
Inital import. Initial fork from f2d678e6e89b6508147086610e985d4e8416e867 (1.0.2 beta). (This change contains substantial changes from the original and effectively starts a new history.)
2014-06-20 20:00:00 +01:00
}
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;
}
Add in missing curly braces part 1. Everything before crypto/ec. Change-Id: Icbfab8e4ffe5cc56bf465eb57d3fdad3959a085c Reviewed-on: https://boringssl-review.googlesource.com/3401 Reviewed-by: Adam Langley <agl@google.com>
2015-02-11 06:16:26 +00:00
if (BN_copy(t, a)) {
Inital import. Initial fork from f2d678e6e89b6508147086610e985d4e8416e867 (1.0.2 beta). (This change contains substantial changes from the original and effectively starts a new history.)
2014-06-20 20:00:00 +01:00
retn = BN_from_montgomery_word(ret, t, mont);
Add in missing curly braces part 1. Everything before crypto/ec. Change-Id: Icbfab8e4ffe5cc56bf465eb57d3fdad3959a085c Reviewed-on: https://boringssl-review.googlesource.com/3401 Reviewed-by: Adam Langley <agl@google.com>
2015-02-11 06:16:26 +00:00
}
Inital import. Initial fork from f2d678e6e89b6508147086610e985d4e8416e867 (1.0.2 beta). (This change contains substantial changes from the original and effectively starts a new history.)
2014-06-20 20:00:00 +01:00
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;
}
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