pineapple/externals/libressl/crypto/ecdsa/ecs_ossl.c
2022-04-24 22:29:35 +02:00

546 lines
14 KiB
C
Executable file

/* $OpenBSD: ecs_ossl.c,v 1.24 2022/04/07 17:37:25 tb Exp $ */
/*
* 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).
*
*/
#include <string.h>
#include <openssl/opensslconf.h>
#include <openssl/err.h>
#include <openssl/obj_mac.h>
#include <openssl/bn.h>
#include "bn_lcl.h"
#include "ecs_locl.h"
static int ecdsa_prepare_digest(const unsigned char *dgst, int dgst_len,
BIGNUM *order, BIGNUM *ret);
static ECDSA_SIG *ecdsa_do_sign(const unsigned char *dgst, int dgst_len,
const BIGNUM *, const BIGNUM *, EC_KEY *eckey);
static int ecdsa_sign_setup(EC_KEY *eckey, BN_CTX *ctx_in, BIGNUM **kinvp,
BIGNUM **rp);
static int ecdsa_do_verify(const unsigned char *dgst, int dgst_len,
const ECDSA_SIG *sig, EC_KEY *eckey);
static ECDSA_METHOD openssl_ecdsa_meth = {
.name = "OpenSSL ECDSA method",
.ecdsa_do_sign = ecdsa_do_sign,
.ecdsa_sign_setup = ecdsa_sign_setup,
.ecdsa_do_verify = ecdsa_do_verify
};
const ECDSA_METHOD *
ECDSA_OpenSSL(void)
{
return &openssl_ecdsa_meth;
}
static int
ecdsa_prepare_digest(const unsigned char *dgst, int dgst_len, BIGNUM *order,
BIGNUM *ret)
{
int dgst_bits, order_bits;
if (!BN_bin2bn(dgst, dgst_len, ret)) {
ECDSAerror(ERR_R_BN_LIB);
return 0;
}
/* FIPS 186-3 6.4: Use order_bits leftmost bits if digest is too long */
dgst_bits = 8 * dgst_len;
order_bits = BN_num_bits(order);
if (dgst_bits > order_bits) {
if (!BN_rshift(ret, ret, dgst_bits - order_bits)) {
ECDSAerror(ERR_R_BN_LIB);
return 0;
}
}
return 1;
}
int
ossl_ecdsa_sign(int type, const unsigned char *dgst, int dlen, unsigned char *sig,
unsigned int *siglen, const BIGNUM *kinv, const BIGNUM *r, EC_KEY *eckey)
{
ECDSA_SIG *s;
if ((s = ECDSA_do_sign_ex(dgst, dlen, kinv, r, eckey)) == NULL) {
*siglen = 0;
return 0;
}
*siglen = i2d_ECDSA_SIG(s, &sig);
ECDSA_SIG_free(s);
return 1;
}
static int
ecdsa_sign_setup(EC_KEY *eckey, BN_CTX *ctx_in, BIGNUM **kinvp, BIGNUM **rp)
{
BN_CTX *ctx = ctx_in;
BIGNUM *k = NULL, *r = NULL, *order = NULL, *X = NULL;
EC_POINT *point = NULL;
const EC_GROUP *group;
int order_bits, ret = 0;
if (eckey == NULL || (group = EC_KEY_get0_group(eckey)) == NULL) {
ECDSAerror(ERR_R_PASSED_NULL_PARAMETER);
return 0;
}
if (ctx == NULL) {
if ((ctx = BN_CTX_new()) == NULL) {
ECDSAerror(ERR_R_MALLOC_FAILURE);
return 0;
}
}
if ((k = BN_new()) == NULL || (r = BN_new()) == NULL ||
(order = BN_new()) == NULL || (X = BN_new()) == NULL) {
ECDSAerror(ERR_R_MALLOC_FAILURE);
goto err;
}
if ((point = EC_POINT_new(group)) == NULL) {
ECDSAerror(ERR_R_EC_LIB);
goto err;
}
if (!EC_GROUP_get_order(group, order, ctx)) {
ECDSAerror(ERR_R_EC_LIB);
goto err;
}
if (BN_cmp(order, BN_value_one()) <= 0) {
ECDSAerror(EC_R_INVALID_GROUP_ORDER);
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 {
do {
if (!BN_rand_range(k, order)) {
ECDSAerror(
ECDSA_R_RANDOM_NUMBER_GENERATION_FAILED);
goto err;
}
} while (BN_is_zero(k));
/*
* 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(r, k, order) ||
!BN_add(X, r, order) ||
!BN_copy(k, BN_num_bits(r) > order_bits ? r : X))
goto err;
BN_set_flags(k, BN_FLG_CONSTTIME);
/* Compute r, the x-coordinate of G * k. */
if (!EC_POINT_mul(group, point, k, NULL, NULL, ctx)) {
ECDSAerror(ERR_R_EC_LIB);
goto err;
}
if (!EC_POINT_get_affine_coordinates(group, point, X, NULL,
ctx)) {
ECDSAerror(ERR_R_EC_LIB);
goto err;
}
if (!BN_nnmod(r, X, order, ctx)) {
ECDSAerror(ERR_R_BN_LIB);
goto err;
}
} while (BN_is_zero(r));
if (BN_mod_inverse_ct(k, k, order, ctx) == NULL) {
ECDSAerror(ERR_R_BN_LIB);
goto err;
}
BN_clear_free(*rp);
BN_clear_free(*kinvp);
*rp = r;
*kinvp = k;
ret = 1;
err:
if (ret == 0) {
BN_clear_free(k);
BN_clear_free(r);
}
if (ctx_in == NULL)
BN_CTX_free(ctx);
BN_free(order);
EC_POINT_free(point);
BN_clear_free(X);
return (ret);
}
/* replace w/ ecdsa_sign_setup() when ECDSA_METHOD gets removed */
int
ossl_ecdsa_sign_setup(EC_KEY *eckey, BN_CTX *ctx_in, BIGNUM **kinvp, BIGNUM **rp)
{
ECDSA_DATA *ecdsa;
if ((ecdsa = ecdsa_check(eckey)) == NULL)
return 0;
return ecdsa->meth->ecdsa_sign_setup(eckey, ctx_in, kinvp, rp);
}
static ECDSA_SIG *
ecdsa_do_sign(const unsigned char *dgst, int dgst_len,
const BIGNUM *in_kinv, const BIGNUM *in_r, EC_KEY *eckey)
{
BIGNUM *b = NULL, *binv = NULL, *bm = NULL, *bxr = NULL;
BIGNUM *kinv = NULL, *m = NULL, *order = NULL, *range = NULL, *s;
const BIGNUM *ckinv, *priv_key;
BN_CTX *ctx = NULL;
const EC_GROUP *group;
ECDSA_SIG *ret;
ECDSA_DATA *ecdsa;
int ok = 0;
ecdsa = ecdsa_check(eckey);
group = EC_KEY_get0_group(eckey);
priv_key = EC_KEY_get0_private_key(eckey);
if (group == NULL || priv_key == NULL || ecdsa == NULL) {
ECDSAerror(ERR_R_PASSED_NULL_PARAMETER);
return NULL;
}
if ((ret = ECDSA_SIG_new()) == NULL) {
ECDSAerror(ERR_R_MALLOC_FAILURE);
return NULL;
}
s = ret->s;
if ((ctx = BN_CTX_new()) == NULL || (order = BN_new()) == NULL ||
(range = BN_new()) == NULL || (b = BN_new()) == NULL ||
(binv = BN_new()) == NULL || (bm = BN_new()) == NULL ||
(bxr = BN_new()) == NULL || (m = BN_new()) == NULL) {
ECDSAerror(ERR_R_MALLOC_FAILURE);
goto err;
}
if (!EC_GROUP_get_order(group, order, ctx)) {
ECDSAerror(ERR_R_EC_LIB);
goto err;
}
if (!ecdsa_prepare_digest(dgst, dgst_len, order, m))
goto err;
do {
if (in_kinv == NULL || in_r == NULL) {
if (!ECDSA_sign_setup(eckey, ctx, &kinv, &ret->r)) {
ECDSAerror(ERR_R_ECDSA_LIB);
goto err;
}
ckinv = kinv;
} else {
ckinv = in_kinv;
if (BN_copy(ret->r, in_r) == NULL) {
ECDSAerror(ERR_R_MALLOC_FAILURE);
goto err;
}
}
/*
* Compute:
*
* s = inv(k)(m + xr) mod order
*
* In order to reduce the possibility of a side-channel attack,
* the following is calculated using a blinding value:
*
* s = inv(b)(bm + bxr)inv(k) mod order
*
* where b is a random value in the range [1, order-1].
*/
/* Generate b in range [1, order-1]. */
if (!BN_sub(range, order, BN_value_one())) {
ECDSAerror(ERR_R_BN_LIB);
goto err;
}
if (!BN_rand_range(b, range)) {
ECDSAerror(ERR_R_BN_LIB);
goto err;
}
if (!BN_add(b, b, BN_value_one())) {
ECDSAerror(ERR_R_BN_LIB);
goto err;
}
if (BN_mod_inverse_ct(binv, b, order, ctx) == NULL) {
ECDSAerror(ERR_R_BN_LIB);
goto err;
}
if (!BN_mod_mul(bxr, b, priv_key, order, ctx)) { /* bx */
ECDSAerror(ERR_R_BN_LIB);
goto err;
}
if (!BN_mod_mul(bxr, bxr, ret->r, order, ctx)) { /* bxr */
ECDSAerror(ERR_R_BN_LIB);
goto err;
}
if (!BN_mod_mul(bm, b, m, order, ctx)) { /* bm */
ECDSAerror(ERR_R_BN_LIB);
goto err;
}
if (!BN_mod_add(s, bm, bxr, order, ctx)) { /* s = bm + bxr */
ECDSAerror(ERR_R_BN_LIB);
goto err;
}
if (!BN_mod_mul(s, s, ckinv, order, ctx)) { /* s = b(m + xr)k^-1 */
ECDSAerror(ERR_R_BN_LIB);
goto err;
}
if (!BN_mod_mul(s, s, binv, order, ctx)) { /* s = (m + xr)k^-1 */
ECDSAerror(ERR_R_BN_LIB);
goto err;
}
if (BN_is_zero(s)) {
/*
* If kinv and r have been supplied by the caller,
* don't generate new kinv and r values
*/
if (in_kinv != NULL && in_r != NULL) {
ECDSAerror(ECDSA_R_NEED_NEW_SETUP_VALUES);
goto err;
}
} else
/* s != 0 => we have a valid signature */
break;
} while (1);
ok = 1;
err:
if (ok == 0) {
ECDSA_SIG_free(ret);
ret = NULL;
}
BN_CTX_free(ctx);
BN_clear_free(b);
BN_clear_free(binv);
BN_clear_free(bm);
BN_clear_free(bxr);
BN_clear_free(kinv);
BN_clear_free(m);
BN_free(order);
BN_free(range);
return ret;
}
/* replace w/ ecdsa_do_sign() when ECDSA_METHOD gets removed */
ECDSA_SIG *
ossl_ecdsa_sign_sig(const unsigned char *dgst, int dgst_len,
const BIGNUM *in_kinv, const BIGNUM *in_r, EC_KEY *eckey)
{
ECDSA_DATA *ecdsa;
if ((ecdsa = ecdsa_check(eckey)) == NULL)
return NULL;
return ecdsa->meth->ecdsa_do_sign(dgst, dgst_len, in_kinv, in_r, eckey);
}
int
ossl_ecdsa_verify(int type, const unsigned char *dgst, int dgst_len,
const unsigned char *sigbuf, int sig_len, EC_KEY *eckey)
{
ECDSA_SIG *s;
unsigned char *der = NULL;
const unsigned char *p = sigbuf;
int derlen = -1;
int ret = -1;
if ((s = ECDSA_SIG_new()) == NULL)
return (ret);
if (d2i_ECDSA_SIG(&s, &p, sig_len) == NULL)
goto err;
/* Ensure signature uses DER and doesn't have trailing garbage */
derlen = i2d_ECDSA_SIG(s, &der);
if (derlen != sig_len || memcmp(sigbuf, der, derlen))
goto err;
ret = ECDSA_do_verify(dgst, dgst_len, s, eckey);
err:
freezero(der, derlen);
ECDSA_SIG_free(s);
return (ret);
}
static int
ecdsa_do_verify(const unsigned char *dgst, int dgst_len, const ECDSA_SIG *sig,
EC_KEY *eckey)
{
BN_CTX *ctx;
BIGNUM *order, *u1, *u2, *m, *X;
EC_POINT *point = NULL;
const EC_GROUP *group;
const EC_POINT *pub_key;
int ret = -1;
if (eckey == NULL || (group = EC_KEY_get0_group(eckey)) == NULL ||
(pub_key = EC_KEY_get0_public_key(eckey)) == NULL || sig == NULL) {
ECDSAerror(ECDSA_R_MISSING_PARAMETERS);
return -1;
}
if ((ctx = BN_CTX_new()) == NULL) {
ECDSAerror(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);
X = BN_CTX_get(ctx);
if (X == NULL) {
ECDSAerror(ERR_R_BN_LIB);
goto err;
}
if (!EC_GROUP_get_order(group, order, ctx)) {
ECDSAerror(ERR_R_EC_LIB);
goto err;
}
/* Verify that r and s are in the range [1, order-1]. */
if (BN_is_zero(sig->r) || BN_is_negative(sig->r) ||
BN_ucmp(sig->r, order) >= 0 ||
BN_is_zero(sig->s) || BN_is_negative(sig->s) ||
BN_ucmp(sig->s, order) >= 0) {
ECDSAerror(ECDSA_R_BAD_SIGNATURE);
ret = 0;
goto err;
}
if (!ecdsa_prepare_digest(dgst, dgst_len, order, m))
goto err;
if (BN_mod_inverse_ct(u2, sig->s, order, ctx) == NULL) { /* w = inv(s) */
ECDSAerror(ERR_R_BN_LIB);
goto err;
}
if (!BN_mod_mul(u1, m, u2, order, ctx)) { /* u1 = mw */
ECDSAerror(ERR_R_BN_LIB);
goto err;
}
if (!BN_mod_mul(u2, sig->r, u2, order, ctx)) { /* u2 = rw */
ECDSAerror(ERR_R_BN_LIB);
goto err;
}
/* Compute the x-coordinate of G * u1 + pub_key * u2. */
if ((point = EC_POINT_new(group)) == NULL) {
ECDSAerror(ERR_R_MALLOC_FAILURE);
goto err;
}
if (!EC_POINT_mul(group, point, u1, pub_key, u2, ctx)) {
ECDSAerror(ERR_R_EC_LIB);
goto err;
}
if (!EC_POINT_get_affine_coordinates(group, point, X, NULL, ctx)) {
ECDSAerror(ERR_R_EC_LIB);
goto err;
}
if (!BN_nnmod(u1, X, order, ctx)) {
ECDSAerror(ERR_R_BN_LIB);
goto err;
}
/* If the signature is correct, the x-coordinate is equal to sig->r. */
ret = (BN_ucmp(u1, sig->r) == 0);
err:
BN_CTX_end(ctx);
BN_CTX_free(ctx);
EC_POINT_free(point);
return ret;
}
/* replace w/ ecdsa_do_verify() when ECDSA_METHOD gets removed */
int
ossl_ecdsa_verify_sig(const unsigned char *dgst, int dgst_len,
const ECDSA_SIG *sig, EC_KEY *eckey)
{
ECDSA_DATA *ecdsa;
if ((ecdsa = ecdsa_check(eckey)) == NULL)
return 0;
return ecdsa->meth->ecdsa_do_verify(dgst, dgst_len, sig, eckey);
}