242 lines
6.9 KiB
C
Executable File
242 lines
6.9 KiB
C
Executable File
/* $OpenBSD: ech_key.c,v 1.9 2019/01/19 01:12:48 tb Exp $ */
|
|
/* ====================================================================
|
|
* Copyright 2002 Sun Microsystems, Inc. ALL RIGHTS RESERVED.
|
|
*
|
|
* The Elliptic Curve Public-Key Crypto Library (ECC Code) included
|
|
* herein is developed by SUN MICROSYSTEMS, INC., and is contributed
|
|
* to the OpenSSL project.
|
|
*
|
|
* The ECC Code is licensed pursuant to the OpenSSL open source
|
|
* license provided below.
|
|
*
|
|
* The ECDH software is originally written by Douglas Stebila of
|
|
* Sun Microsystems Laboratories.
|
|
*
|
|
*/
|
|
/* ====================================================================
|
|
* Copyright (c) 1998-2003 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 <limits.h>
|
|
#include <string.h>
|
|
|
|
#include <openssl/opensslconf.h>
|
|
|
|
#include <openssl/bn.h>
|
|
#include <openssl/err.h>
|
|
#include <openssl/obj_mac.h>
|
|
#include <openssl/sha.h>
|
|
|
|
#include "ech_locl.h"
|
|
#include "ec_lcl.h"
|
|
|
|
static int ecdh_compute_key(void *out, size_t len, const EC_POINT *pub_key,
|
|
EC_KEY *ecdh,
|
|
void *(*KDF)(const void *in, size_t inlen, void *out, size_t *outlen));
|
|
|
|
/*
|
|
* This implementation is based on the following primitives in the IEEE 1363
|
|
* standard:
|
|
* - ECKAS-DH1
|
|
* - ECSVDP-DH
|
|
* Finally an optional KDF is applied.
|
|
*/
|
|
static int
|
|
ecdh_compute_key(void *out, size_t outlen, const EC_POINT *pub_key,
|
|
EC_KEY *ecdh,
|
|
void *(*KDF)(const void *in, size_t inlen, void *out, size_t *outlen))
|
|
{
|
|
BN_CTX *ctx;
|
|
EC_POINT *tmp = NULL;
|
|
BIGNUM *x = NULL, *y = NULL;
|
|
const BIGNUM *priv_key;
|
|
const EC_GROUP* group;
|
|
int ret = -1;
|
|
size_t buflen, len;
|
|
unsigned char *buf = NULL;
|
|
|
|
if (outlen > INT_MAX) {
|
|
/* Sort of, anyway. */
|
|
ECDHerror(ERR_R_MALLOC_FAILURE);
|
|
return -1;
|
|
}
|
|
|
|
if ((ctx = BN_CTX_new()) == NULL)
|
|
goto err;
|
|
BN_CTX_start(ctx);
|
|
if ((x = BN_CTX_get(ctx)) == NULL)
|
|
goto err;
|
|
if ((y = BN_CTX_get(ctx)) == NULL)
|
|
goto err;
|
|
|
|
priv_key = EC_KEY_get0_private_key(ecdh);
|
|
if (priv_key == NULL) {
|
|
ECDHerror(ECDH_R_NO_PRIVATE_VALUE);
|
|
goto err;
|
|
}
|
|
|
|
group = EC_KEY_get0_group(ecdh);
|
|
|
|
if (!EC_POINT_is_on_curve(group, pub_key, ctx))
|
|
goto err;
|
|
|
|
if ((tmp = EC_POINT_new(group)) == NULL) {
|
|
ECDHerror(ERR_R_MALLOC_FAILURE);
|
|
goto err;
|
|
}
|
|
|
|
if (!EC_POINT_mul(group, tmp, NULL, pub_key, priv_key, ctx)) {
|
|
ECDHerror(ECDH_R_POINT_ARITHMETIC_FAILURE);
|
|
goto err;
|
|
}
|
|
|
|
if (EC_METHOD_get_field_type(EC_GROUP_method_of(group)) ==
|
|
NID_X9_62_prime_field) {
|
|
if (!EC_POINT_get_affine_coordinates_GFp(group, tmp, x, y,
|
|
ctx)) {
|
|
ECDHerror(ECDH_R_POINT_ARITHMETIC_FAILURE);
|
|
goto err;
|
|
}
|
|
}
|
|
#ifndef OPENSSL_NO_EC2M
|
|
else {
|
|
if (!EC_POINT_get_affine_coordinates_GF2m(group, tmp, x, y,
|
|
ctx)) {
|
|
ECDHerror(ECDH_R_POINT_ARITHMETIC_FAILURE);
|
|
goto err;
|
|
}
|
|
}
|
|
#endif
|
|
|
|
buflen = ECDH_size(ecdh);
|
|
len = BN_num_bytes(x);
|
|
if (len > buflen) {
|
|
ECDHerror(ERR_R_INTERNAL_ERROR);
|
|
goto err;
|
|
}
|
|
if (KDF == NULL && outlen < buflen) {
|
|
/* The resulting key would be truncated. */
|
|
ECDHerror(ECDH_R_KEY_TRUNCATION);
|
|
goto err;
|
|
}
|
|
if ((buf = malloc(buflen)) == NULL) {
|
|
ECDHerror(ERR_R_MALLOC_FAILURE);
|
|
goto err;
|
|
}
|
|
|
|
memset(buf, 0, buflen - len);
|
|
if (len != (size_t)BN_bn2bin(x, buf + buflen - len)) {
|
|
ECDHerror(ERR_R_BN_LIB);
|
|
goto err;
|
|
}
|
|
|
|
if (KDF != NULL) {
|
|
if (KDF(buf, buflen, out, &outlen) == NULL) {
|
|
ECDHerror(ECDH_R_KDF_FAILED);
|
|
goto err;
|
|
}
|
|
ret = outlen;
|
|
} else {
|
|
/* No KDF, just copy out the key and zero the rest. */
|
|
if (outlen > buflen) {
|
|
memset((void *)((uintptr_t)out + buflen), 0, outlen - buflen);
|
|
outlen = buflen;
|
|
}
|
|
memcpy(out, buf, outlen);
|
|
ret = outlen;
|
|
}
|
|
|
|
err:
|
|
EC_POINT_free(tmp);
|
|
if (ctx)
|
|
BN_CTX_end(ctx);
|
|
BN_CTX_free(ctx);
|
|
free(buf);
|
|
return (ret);
|
|
}
|
|
|
|
static ECDH_METHOD openssl_ecdh_meth = {
|
|
.name = "OpenSSL ECDH method",
|
|
.compute_key = ecdh_compute_key
|
|
};
|
|
|
|
const ECDH_METHOD *
|
|
ECDH_OpenSSL(void)
|
|
{
|
|
return &openssl_ecdh_meth;
|
|
}
|
|
|
|
/* replace w/ ecdh_compute_key() when ECDH_METHOD gets removed */
|
|
int
|
|
ossl_ecdh_compute_key(void *out, size_t outlen, const EC_POINT *pub_key,
|
|
EC_KEY *eckey,
|
|
void *(*KDF)(const void *in, size_t inlen, void *out, size_t *outlen))
|
|
{
|
|
ECDH_DATA *ecdh;
|
|
|
|
if ((ecdh = ecdh_check(eckey)) == NULL)
|
|
return 0;
|
|
return ecdh->meth->compute_key(out, outlen, pub_key, eckey, KDF);
|
|
}
|
|
|
|
int
|
|
ECDH_compute_key(void *out, size_t outlen, const EC_POINT *pub_key,
|
|
EC_KEY *eckey,
|
|
void *(*KDF)(const void *in, size_t inlen, void *out, size_t *outlen))
|
|
{
|
|
if (eckey->meth->compute_key != NULL)
|
|
return eckey->meth->compute_key(out, outlen, pub_key, eckey, KDF);
|
|
ECerror(EC_R_NOT_IMPLEMENTED);
|
|
return 0;
|
|
}
|