376 lines
10 KiB
C
376 lines
10 KiB
C
/* Originally written by Bodo Moeller for the OpenSSL project.
|
|
* ====================================================================
|
|
* Copyright (c) 1998-2005 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 Sun Microsystems, Inc. ALL RIGHTS RESERVED.
|
|
*
|
|
* Portions of the attached software ("Contribution") are developed by
|
|
* SUN MICROSYSTEMS, INC., and are contributed to the OpenSSL project.
|
|
*
|
|
* The Contribution is licensed pursuant to the OpenSSL open source
|
|
* license provided above.
|
|
*
|
|
* The elliptic curve binary polynomial software is originally written by
|
|
* Sheueling Chang Shantz and Douglas Stebila of Sun Microsystems
|
|
* Laboratories. */
|
|
|
|
#include <openssl/ec.h>
|
|
|
|
#include <openssl/bn.h>
|
|
#include <openssl/err.h>
|
|
|
|
#include "internal.h"
|
|
|
|
|
|
static size_t ec_GFp_simple_point2oct(const EC_GROUP *group,
|
|
const EC_POINT *point,
|
|
point_conversion_form_t form,
|
|
uint8_t *buf, size_t len, BN_CTX *ctx) {
|
|
size_t ret;
|
|
BN_CTX *new_ctx = NULL;
|
|
int used_ctx = 0;
|
|
BIGNUM *x, *y;
|
|
size_t field_len, i;
|
|
|
|
if ((form != POINT_CONVERSION_COMPRESSED) &&
|
|
(form != POINT_CONVERSION_UNCOMPRESSED)) {
|
|
OPENSSL_PUT_ERROR(EC, EC_R_INVALID_FORM);
|
|
goto err;
|
|
}
|
|
|
|
if (EC_POINT_is_at_infinity(group, point)) {
|
|
OPENSSL_PUT_ERROR(EC, EC_R_POINT_AT_INFINITY);
|
|
goto err;
|
|
}
|
|
|
|
// ret := required output buffer length
|
|
field_len = BN_num_bytes(&group->field);
|
|
ret =
|
|
(form == POINT_CONVERSION_COMPRESSED) ? 1 + field_len : 1 + 2 * field_len;
|
|
|
|
// if 'buf' is NULL, just return required length
|
|
if (buf != NULL) {
|
|
if (len < ret) {
|
|
OPENSSL_PUT_ERROR(EC, EC_R_BUFFER_TOO_SMALL);
|
|
goto err;
|
|
}
|
|
|
|
if (ctx == NULL) {
|
|
ctx = new_ctx = BN_CTX_new();
|
|
if (ctx == NULL) {
|
|
goto err;
|
|
}
|
|
}
|
|
|
|
BN_CTX_start(ctx);
|
|
used_ctx = 1;
|
|
x = BN_CTX_get(ctx);
|
|
y = BN_CTX_get(ctx);
|
|
if (y == NULL) {
|
|
goto err;
|
|
}
|
|
|
|
if (!EC_POINT_get_affine_coordinates_GFp(group, point, x, y, ctx)) {
|
|
goto err;
|
|
}
|
|
|
|
if ((form == POINT_CONVERSION_COMPRESSED) &&
|
|
BN_is_odd(y)) {
|
|
buf[0] = form + 1;
|
|
} else {
|
|
buf[0] = form;
|
|
}
|
|
i = 1;
|
|
|
|
if (!BN_bn2bin_padded(buf + i, field_len, x)) {
|
|
OPENSSL_PUT_ERROR(EC, ERR_R_INTERNAL_ERROR);
|
|
goto err;
|
|
}
|
|
i += field_len;
|
|
|
|
if (form == POINT_CONVERSION_UNCOMPRESSED) {
|
|
if (!BN_bn2bin_padded(buf + i, field_len, y)) {
|
|
OPENSSL_PUT_ERROR(EC, ERR_R_INTERNAL_ERROR);
|
|
goto err;
|
|
}
|
|
i += field_len;
|
|
}
|
|
|
|
if (i != ret) {
|
|
OPENSSL_PUT_ERROR(EC, ERR_R_INTERNAL_ERROR);
|
|
goto err;
|
|
}
|
|
}
|
|
|
|
if (used_ctx) {
|
|
BN_CTX_end(ctx);
|
|
}
|
|
BN_CTX_free(new_ctx);
|
|
return ret;
|
|
|
|
err:
|
|
if (used_ctx) {
|
|
BN_CTX_end(ctx);
|
|
}
|
|
BN_CTX_free(new_ctx);
|
|
return 0;
|
|
}
|
|
|
|
|
|
static int ec_GFp_simple_oct2point(const EC_GROUP *group, EC_POINT *point,
|
|
const uint8_t *buf, size_t len,
|
|
BN_CTX *ctx) {
|
|
point_conversion_form_t form;
|
|
int y_bit;
|
|
BN_CTX *new_ctx = NULL;
|
|
BIGNUM *x, *y;
|
|
size_t field_len, enc_len;
|
|
int ret = 0;
|
|
|
|
if (len == 0) {
|
|
OPENSSL_PUT_ERROR(EC, EC_R_BUFFER_TOO_SMALL);
|
|
return 0;
|
|
}
|
|
form = buf[0];
|
|
y_bit = form & 1;
|
|
form = form & ~1U;
|
|
if ((form != POINT_CONVERSION_COMPRESSED &&
|
|
form != POINT_CONVERSION_UNCOMPRESSED) ||
|
|
(form == POINT_CONVERSION_UNCOMPRESSED && y_bit)) {
|
|
OPENSSL_PUT_ERROR(EC, EC_R_INVALID_ENCODING);
|
|
return 0;
|
|
}
|
|
|
|
field_len = BN_num_bytes(&group->field);
|
|
enc_len =
|
|
(form == POINT_CONVERSION_COMPRESSED) ? 1 + field_len : 1 + 2 * field_len;
|
|
|
|
if (len != enc_len) {
|
|
OPENSSL_PUT_ERROR(EC, EC_R_INVALID_ENCODING);
|
|
return 0;
|
|
}
|
|
|
|
if (ctx == NULL) {
|
|
ctx = new_ctx = BN_CTX_new();
|
|
if (ctx == NULL) {
|
|
return 0;
|
|
}
|
|
}
|
|
|
|
BN_CTX_start(ctx);
|
|
x = BN_CTX_get(ctx);
|
|
y = BN_CTX_get(ctx);
|
|
if (x == NULL || y == NULL) {
|
|
goto err;
|
|
}
|
|
|
|
if (!BN_bin2bn(buf + 1, field_len, x)) {
|
|
goto err;
|
|
}
|
|
if (BN_ucmp(x, &group->field) >= 0) {
|
|
OPENSSL_PUT_ERROR(EC, EC_R_INVALID_ENCODING);
|
|
goto err;
|
|
}
|
|
|
|
if (form == POINT_CONVERSION_COMPRESSED) {
|
|
if (!EC_POINT_set_compressed_coordinates_GFp(group, point, x, y_bit, ctx)) {
|
|
goto err;
|
|
}
|
|
} else {
|
|
if (!BN_bin2bn(buf + 1 + field_len, field_len, y)) {
|
|
goto err;
|
|
}
|
|
if (BN_ucmp(y, &group->field) >= 0) {
|
|
OPENSSL_PUT_ERROR(EC, EC_R_INVALID_ENCODING);
|
|
goto err;
|
|
}
|
|
|
|
if (!EC_POINT_set_affine_coordinates_GFp(group, point, x, y, ctx)) {
|
|
goto err;
|
|
}
|
|
}
|
|
|
|
ret = 1;
|
|
|
|
err:
|
|
BN_CTX_end(ctx);
|
|
BN_CTX_free(new_ctx);
|
|
return ret;
|
|
}
|
|
|
|
int EC_POINT_oct2point(const EC_GROUP *group, EC_POINT *point,
|
|
const uint8_t *buf, size_t len, BN_CTX *ctx) {
|
|
if (EC_GROUP_cmp(group, point->group, NULL) != 0) {
|
|
OPENSSL_PUT_ERROR(EC, EC_R_INCOMPATIBLE_OBJECTS);
|
|
return 0;
|
|
}
|
|
return ec_GFp_simple_oct2point(group, point, buf, len, ctx);
|
|
}
|
|
|
|
size_t EC_POINT_point2oct(const EC_GROUP *group, const EC_POINT *point,
|
|
point_conversion_form_t form, uint8_t *buf,
|
|
size_t len, BN_CTX *ctx) {
|
|
if (EC_GROUP_cmp(group, point->group, NULL) != 0) {
|
|
OPENSSL_PUT_ERROR(EC, EC_R_INCOMPATIBLE_OBJECTS);
|
|
return 0;
|
|
}
|
|
return ec_GFp_simple_point2oct(group, point, form, buf, len, ctx);
|
|
}
|
|
|
|
int EC_POINT_set_compressed_coordinates_GFp(const EC_GROUP *group,
|
|
EC_POINT *point, const BIGNUM *x,
|
|
int y_bit, BN_CTX *ctx) {
|
|
if (EC_GROUP_cmp(group, point->group, NULL) != 0) {
|
|
OPENSSL_PUT_ERROR(EC, EC_R_INCOMPATIBLE_OBJECTS);
|
|
return 0;
|
|
}
|
|
|
|
if (BN_is_negative(x) || BN_cmp(x, &group->field) >= 0) {
|
|
OPENSSL_PUT_ERROR(EC, EC_R_INVALID_COMPRESSED_POINT);
|
|
return 0;
|
|
}
|
|
|
|
BN_CTX *new_ctx = NULL;
|
|
int ret = 0;
|
|
|
|
ERR_clear_error();
|
|
|
|
if (ctx == NULL) {
|
|
ctx = new_ctx = BN_CTX_new();
|
|
if (ctx == NULL) {
|
|
return 0;
|
|
}
|
|
}
|
|
|
|
y_bit = (y_bit != 0);
|
|
|
|
BN_CTX_start(ctx);
|
|
BIGNUM *tmp1 = BN_CTX_get(ctx);
|
|
BIGNUM *tmp2 = BN_CTX_get(ctx);
|
|
BIGNUM *a = BN_CTX_get(ctx);
|
|
BIGNUM *b = BN_CTX_get(ctx);
|
|
BIGNUM *y = BN_CTX_get(ctx);
|
|
if (y == NULL ||
|
|
!EC_GROUP_get_curve_GFp(group, NULL, a, b, ctx)) {
|
|
goto err;
|
|
}
|
|
|
|
// Recover y. We have a Weierstrass equation
|
|
// y^2 = x^3 + a*x + b,
|
|
// so y is one of the square roots of x^3 + a*x + b.
|
|
|
|
// tmp1 := x^3
|
|
if (!BN_mod_sqr(tmp2, x, &group->field, ctx) ||
|
|
!BN_mod_mul(tmp1, tmp2, x, &group->field, ctx)) {
|
|
goto err;
|
|
}
|
|
|
|
// tmp1 := tmp1 + a*x
|
|
if (group->a_is_minus3) {
|
|
if (!BN_mod_lshift1_quick(tmp2, x, &group->field) ||
|
|
!BN_mod_add_quick(tmp2, tmp2, x, &group->field) ||
|
|
!BN_mod_sub_quick(tmp1, tmp1, tmp2, &group->field)) {
|
|
goto err;
|
|
}
|
|
} else {
|
|
if (!BN_mod_mul(tmp2, a, x, &group->field, ctx) ||
|
|
!BN_mod_add_quick(tmp1, tmp1, tmp2, &group->field)) {
|
|
goto err;
|
|
}
|
|
}
|
|
|
|
// tmp1 := tmp1 + b
|
|
if (!BN_mod_add_quick(tmp1, tmp1, b, &group->field)) {
|
|
goto err;
|
|
}
|
|
|
|
if (!BN_mod_sqrt(y, tmp1, &group->field, ctx)) {
|
|
unsigned long err = ERR_peek_last_error();
|
|
|
|
if (ERR_GET_LIB(err) == ERR_LIB_BN &&
|
|
ERR_GET_REASON(err) == BN_R_NOT_A_SQUARE) {
|
|
ERR_clear_error();
|
|
OPENSSL_PUT_ERROR(EC, EC_R_INVALID_COMPRESSED_POINT);
|
|
} else {
|
|
OPENSSL_PUT_ERROR(EC, ERR_R_BN_LIB);
|
|
}
|
|
goto err;
|
|
}
|
|
|
|
if (y_bit != BN_is_odd(y)) {
|
|
if (BN_is_zero(y)) {
|
|
OPENSSL_PUT_ERROR(EC, EC_R_INVALID_COMPRESSION_BIT);
|
|
goto err;
|
|
}
|
|
if (!BN_usub(y, &group->field, y)) {
|
|
goto err;
|
|
}
|
|
}
|
|
if (y_bit != BN_is_odd(y)) {
|
|
OPENSSL_PUT_ERROR(EC, ERR_R_INTERNAL_ERROR);
|
|
goto err;
|
|
}
|
|
|
|
if (!EC_POINT_set_affine_coordinates_GFp(group, point, x, y, ctx)) {
|
|
goto err;
|
|
}
|
|
|
|
ret = 1;
|
|
|
|
err:
|
|
BN_CTX_end(ctx);
|
|
BN_CTX_free(new_ctx);
|
|
return ret;
|
|
}
|