-/* crypto/ec/ecdsa_ossl.c */
/*
- * Written by Nils Larsch for the OpenSSL project
- */
-/* ====================================================================
- * Copyright (c) 1998-2004 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).
+ * Copyright 2002-2017 The OpenSSL Project Authors. All Rights Reserved.
*
+ * Licensed under the OpenSSL license (the "License"). You may not use
+ * this file except in compliance with the License. You can obtain a copy
+ * in the file LICENSE in the source distribution or at
+ * https://www.openssl.org/source/license.html
*/
#include <string.h>
const unsigned char *dgst, int dlen)
{
BN_CTX *ctx = NULL;
- BIGNUM *k = NULL, *r = NULL, *order = NULL, *X = NULL;
+ BIGNUM *k = NULL, *r = NULL, *X = NULL;
+ const BIGNUM *order;
EC_POINT *tmp_point = NULL;
const EC_GROUP *group;
int ret = 0;
+ int order_bits;
if (eckey == NULL || (group = EC_KEY_get0_group(eckey)) == NULL) {
ECerr(EC_F_ECDSA_SIGN_SETUP, ERR_R_PASSED_NULL_PARAMETER);
return 0;
}
+ if (!EC_KEY_can_sign(eckey)) {
+ ECerr(EC_F_ECDSA_SIGN_SETUP, EC_R_CURVE_DOES_NOT_SUPPORT_SIGNING);
+ return 0;
+ }
+
if (ctx_in == NULL) {
if ((ctx = BN_CTX_new()) == NULL) {
ECerr(EC_F_ECDSA_SIGN_SETUP, ERR_R_MALLOC_FAILURE);
k = BN_new(); /* this value is later returned in *kinvp */
r = BN_new(); /* this value is later returned in *rp */
- order = BN_new();
X = BN_new();
- if (k == NULL || r == NULL || order == NULL || X == NULL) {
+ if (k == NULL || r == NULL || X == NULL) {
ECerr(EC_F_ECDSA_SIGN_SETUP, ERR_R_MALLOC_FAILURE);
goto err;
}
ECerr(EC_F_ECDSA_SIGN_SETUP, ERR_R_EC_LIB);
goto err;
}
- if (!EC_GROUP_get_order(group, order, ctx)) {
+ order = EC_GROUP_get0_order(group);
+ if (order == NULL) {
ECerr(EC_F_ECDSA_SIGN_SETUP, ERR_R_EC_LIB);
goto err;
}
+ /* Preallocate space */
+ order_bits = BN_num_bits(order);
+ if (!BN_set_bit(k, order_bits)
+ || !BN_set_bit(r, order_bits)
+ || !BN_set_bit(X, order_bits))
+ goto err;
+
do {
/* get random k */
do
/*
* We do not want timing information to leak the length of k, so we
* compute G*k using an equivalent scalar of fixed bit-length.
+ *
+ * We unconditionally perform both of these additions to prevent a
+ * small timing information leakage. We then choose the sum that is
+ * one bit longer than the order. This guarantees the code
+ * path used in the constant time implementations elsewhere.
+ *
+ * TODO: revisit the BN_copy aiming for a memory access agnostic
+ * conditional copy.
*/
-
- if (!BN_add(k, k, order))
+ if (!BN_add(r, k, order)
+ || !BN_add(X, r, order)
+ || !BN_copy(k, BN_num_bits(r) > order_bits ? r : X))
goto err;
- if (BN_num_bits(k) <= BN_num_bits(order))
- if (!BN_add(k, k, order))
- goto err;
/* compute r the x-coordinate of generator * k */
if (!EC_POINT_mul(group, tmp_point, k, NULL, NULL, ctx)) {
}
if (ctx != ctx_in)
BN_CTX_free(ctx);
- BN_free(order);
EC_POINT_free(tmp_point);
BN_clear_free(X);
return (ret);
EC_KEY *eckey)
{
int ok = 0, i;
- BIGNUM *kinv = NULL, *s, *m = NULL, *tmp = NULL, *order = NULL;
- const BIGNUM *ckinv;
+ BIGNUM *kinv = NULL, *s, *m = NULL, *tmp = NULL, *blind = NULL;
+ BIGNUM *blindm = NULL;
+ const BIGNUM *order, *ckinv;
BN_CTX *ctx = NULL;
const EC_GROUP *group;
ECDSA_SIG *ret;
return NULL;
}
+ if (!EC_KEY_can_sign(eckey)) {
+ ECerr(EC_F_OSSL_ECDSA_SIGN_SIG, EC_R_CURVE_DOES_NOT_SUPPORT_SIGNING);
+ return NULL;
+ }
+
ret = ECDSA_SIG_new();
if (ret == NULL) {
ECerr(EC_F_OSSL_ECDSA_SIGN_SIG, ERR_R_MALLOC_FAILURE);
return NULL;
}
+ ret->r = BN_new();
+ ret->s = BN_new();
+ if (ret->r == NULL || ret->s == NULL) {
+ ECerr(EC_F_OSSL_ECDSA_SIGN_SIG, ERR_R_MALLOC_FAILURE);
+ goto err;
+ }
s = ret->s;
- if ((ctx = BN_CTX_new()) == NULL || (order = BN_new()) == NULL ||
- (tmp = BN_new()) == NULL || (m = BN_new()) == NULL) {
+ ctx = BN_CTX_secure_new();
+ if (ctx == NULL) {
+ ECerr(EC_F_OSSL_ECDSA_SIGN_SIG, ERR_R_MALLOC_FAILURE);
+ goto err;
+ }
+
+ BN_CTX_start(ctx);
+ tmp = BN_CTX_get(ctx);
+ m = BN_CTX_get(ctx);
+ blind = BN_CTX_get(ctx);
+ blindm = BN_CTX_get(ctx);
+ if (blindm == NULL) {
ECerr(EC_F_OSSL_ECDSA_SIGN_SIG, ERR_R_MALLOC_FAILURE);
goto err;
}
- if (!EC_GROUP_get_order(group, order, ctx)) {
+ order = EC_GROUP_get0_order(group);
+ if (order == NULL) {
ECerr(EC_F_OSSL_ECDSA_SIGN_SIG, ERR_R_EC_LIB);
goto err;
}
}
}
- if (!BN_mod_mul(tmp, priv_key, ret->r, order, ctx)) {
+ /*
+ * The normal signature calculation is:
+ *
+ * s := k^-1 * (m + r * priv_key) mod order
+ *
+ * We will blind this to protect against side channel attacks
+ *
+ * s := blind^-1 * k^-1 * (blind * m + blind * r * priv_key) mod order
+ */
+
+ /* Generate a blinding value */
+ do {
+ if (!BN_rand(blind, BN_num_bits(order) - 1, BN_RAND_TOP_ANY,
+ BN_RAND_BOTTOM_ANY))
+ goto err;
+ } while (BN_is_zero(blind));
+ BN_set_flags(blind, BN_FLG_CONSTTIME);
+ BN_set_flags(blindm, BN_FLG_CONSTTIME);
+ BN_set_flags(tmp, BN_FLG_CONSTTIME);
+
+ /* tmp := blind * priv_key * r mod order */
+ if (!BN_mod_mul(tmp, blind, priv_key, order, ctx)) {
+ ECerr(EC_F_OSSL_ECDSA_SIGN_SIG, ERR_R_BN_LIB);
+ goto err;
+ }
+ if (!BN_mod_mul(tmp, tmp, ret->r, order, ctx)) {
+ ECerr(EC_F_OSSL_ECDSA_SIGN_SIG, ERR_R_BN_LIB);
+ goto err;
+ }
+
+ /* blindm := blind * m mod order */
+ if (!BN_mod_mul(blindm, blind, m, order, ctx)) {
ECerr(EC_F_OSSL_ECDSA_SIGN_SIG, ERR_R_BN_LIB);
goto err;
}
- if (!BN_mod_add_quick(s, tmp, m, order)) {
+
+ /* s : = (blind * priv_key * r) + (blind * m) mod order */
+ if (!BN_mod_add_quick(s, tmp, blindm, order)) {
ECerr(EC_F_OSSL_ECDSA_SIGN_SIG, ERR_R_BN_LIB);
goto err;
}
+
+ /* s := s * k^-1 mod order */
if (!BN_mod_mul(s, s, ckinv, order, ctx)) {
ECerr(EC_F_OSSL_ECDSA_SIGN_SIG, ERR_R_BN_LIB);
goto err;
}
+
+ /* s:= s * blind^-1 mod order */
+ if (BN_mod_inverse(blind, blind, order, ctx) == NULL) {
+ ECerr(EC_F_OSSL_ECDSA_SIGN_SIG, ERR_R_BN_LIB);
+ goto err;
+ }
+ if (!BN_mod_mul(s, s, blind, order, ctx)) {
+ ECerr(EC_F_OSSL_ECDSA_SIGN_SIG, ERR_R_BN_LIB);
+ goto err;
+ }
+
if (BN_is_zero(s)) {
/*
* if kinv and r have been supplied by the caller don't to
ECDSA_SIG_free(ret);
ret = NULL;
}
+ BN_CTX_end(ctx);
BN_CTX_free(ctx);
- BN_clear_free(m);
- BN_clear_free(tmp);
- BN_free(order);
BN_clear_free(kinv);
return ret;
}
{
int ret = -1, i;
BN_CTX *ctx;
- BIGNUM *order, *u1, *u2, *m, *X;
+ const BIGNUM *order;
+ BIGNUM *u1, *u2, *m, *X;
EC_POINT *point = NULL;
const EC_GROUP *group;
const EC_POINT *pub_key;
return -1;
}
+ if (!EC_KEY_can_sign(eckey)) {
+ ECerr(EC_F_OSSL_ECDSA_VERIFY_SIG, EC_R_CURVE_DOES_NOT_SUPPORT_SIGNING);
+ return -1;
+ }
+
ctx = BN_CTX_new();
if (ctx == NULL) {
ECerr(EC_F_OSSL_ECDSA_VERIFY_SIG, ERR_R_MALLOC_FAILURE);
return -1;
}
BN_CTX_start(ctx);
- order = BN_CTX_get(ctx);
u1 = BN_CTX_get(ctx);
u2 = BN_CTX_get(ctx);
m = BN_CTX_get(ctx);
goto err;
}
- if (!EC_GROUP_get_order(group, order, ctx)) {
+ order = EC_GROUP_get0_order(group);
+ if (order == NULL) {
ECerr(EC_F_OSSL_ECDSA_VERIFY_SIG, ERR_R_EC_LIB);
goto err;
}
projects / openssl.git / blobdiff