241 lines
6.9 KiB
C
Executable file
241 lines
6.9 KiB
C
Executable file
/* $OpenBSD: ech_key.c,v 1.9 2019/01/19 01:12:48 tb Exp $ */
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/* ====================================================================
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* Copyright 2002 Sun Microsystems, Inc. ALL RIGHTS RESERVED.
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*
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* The Elliptic Curve Public-Key Crypto Library (ECC Code) included
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* herein is developed by SUN MICROSYSTEMS, INC., and is contributed
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* to the OpenSSL project.
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*
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* The ECC Code is licensed pursuant to the OpenSSL open source
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* license provided below.
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*
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* The ECDH software is originally written by Douglas Stebila of
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* Sun Microsystems Laboratories.
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*
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*/
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/* ====================================================================
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* Copyright (c) 1998-2003 The OpenSSL Project. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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*
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in
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* the documentation and/or other materials provided with the
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* distribution.
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*
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* 3. All advertising materials mentioning features or use of this
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* software must display the following acknowledgment:
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* "This product includes software developed by the OpenSSL Project
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* for use in the OpenSSL Toolkit. (http://www.OpenSSL.org/)"
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*
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* 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
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* endorse or promote products derived from this software without
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* prior written permission. For written permission, please contact
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* openssl-core@OpenSSL.org.
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*
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* 5. Products derived from this software may not be called "OpenSSL"
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* nor may "OpenSSL" appear in their names without prior written
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* permission of the OpenSSL Project.
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*
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* 6. Redistributions of any form whatsoever must retain the following
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* acknowledgment:
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* "This product includes software developed by the OpenSSL Project
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* for use in the OpenSSL Toolkit (http://www.OpenSSL.org/)"
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*
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* THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
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* EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OpenSSL PROJECT OR
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* ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
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* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
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* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
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* OF THE POSSIBILITY OF SUCH DAMAGE.
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* ====================================================================
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*
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* This product includes cryptographic software written by Eric Young
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* (eay@cryptsoft.com). This product includes software written by Tim
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* Hudson (tjh@cryptsoft.com).
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*
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*/
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#include <limits.h>
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#include <string.h>
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#include <openssl/opensslconf.h>
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#include <openssl/bn.h>
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#include <openssl/err.h>
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#include <openssl/obj_mac.h>
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#include <openssl/sha.h>
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#include "ech_locl.h"
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#include "ec_lcl.h"
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static int ecdh_compute_key(void *out, size_t len, const EC_POINT *pub_key,
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EC_KEY *ecdh,
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void *(*KDF)(const void *in, size_t inlen, void *out, size_t *outlen));
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/*
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* This implementation is based on the following primitives in the IEEE 1363
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* standard:
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* - ECKAS-DH1
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* - ECSVDP-DH
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* Finally an optional KDF is applied.
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*/
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static int
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ecdh_compute_key(void *out, size_t outlen, const EC_POINT *pub_key,
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EC_KEY *ecdh,
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void *(*KDF)(const void *in, size_t inlen, void *out, size_t *outlen))
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{
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BN_CTX *ctx;
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EC_POINT *tmp = NULL;
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BIGNUM *x = NULL, *y = NULL;
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const BIGNUM *priv_key;
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const EC_GROUP* group;
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int ret = -1;
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size_t buflen, len;
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unsigned char *buf = NULL;
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if (outlen > INT_MAX) {
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/* Sort of, anyway. */
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ECDHerror(ERR_R_MALLOC_FAILURE);
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return -1;
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}
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if ((ctx = BN_CTX_new()) == NULL)
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goto err;
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BN_CTX_start(ctx);
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if ((x = BN_CTX_get(ctx)) == NULL)
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goto err;
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if ((y = BN_CTX_get(ctx)) == NULL)
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goto err;
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priv_key = EC_KEY_get0_private_key(ecdh);
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if (priv_key == NULL) {
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ECDHerror(ECDH_R_NO_PRIVATE_VALUE);
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goto err;
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}
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group = EC_KEY_get0_group(ecdh);
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if (!EC_POINT_is_on_curve(group, pub_key, ctx))
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goto err;
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if ((tmp = EC_POINT_new(group)) == NULL) {
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ECDHerror(ERR_R_MALLOC_FAILURE);
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goto err;
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}
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if (!EC_POINT_mul(group, tmp, NULL, pub_key, priv_key, ctx)) {
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ECDHerror(ECDH_R_POINT_ARITHMETIC_FAILURE);
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goto err;
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}
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if (EC_METHOD_get_field_type(EC_GROUP_method_of(group)) ==
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NID_X9_62_prime_field) {
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if (!EC_POINT_get_affine_coordinates_GFp(group, tmp, x, y,
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ctx)) {
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ECDHerror(ECDH_R_POINT_ARITHMETIC_FAILURE);
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goto err;
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}
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}
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#ifndef OPENSSL_NO_EC2M
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else {
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if (!EC_POINT_get_affine_coordinates_GF2m(group, tmp, x, y,
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ctx)) {
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ECDHerror(ECDH_R_POINT_ARITHMETIC_FAILURE);
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goto err;
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}
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}
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#endif
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buflen = ECDH_size(ecdh);
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len = BN_num_bytes(x);
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if (len > buflen) {
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ECDHerror(ERR_R_INTERNAL_ERROR);
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goto err;
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}
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if (KDF == NULL && outlen < buflen) {
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/* The resulting key would be truncated. */
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ECDHerror(ECDH_R_KEY_TRUNCATION);
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goto err;
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}
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if ((buf = malloc(buflen)) == NULL) {
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ECDHerror(ERR_R_MALLOC_FAILURE);
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goto err;
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}
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memset(buf, 0, buflen - len);
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if (len != (size_t)BN_bn2bin(x, buf + buflen - len)) {
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ECDHerror(ERR_R_BN_LIB);
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goto err;
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}
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if (KDF != NULL) {
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if (KDF(buf, buflen, out, &outlen) == NULL) {
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ECDHerror(ECDH_R_KDF_FAILED);
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goto err;
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}
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ret = outlen;
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} else {
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/* No KDF, just copy out the key and zero the rest. */
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if (outlen > buflen) {
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memset((void *)((uintptr_t)out + buflen), 0, outlen - buflen);
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outlen = buflen;
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}
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memcpy(out, buf, outlen);
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ret = outlen;
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}
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err:
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EC_POINT_free(tmp);
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if (ctx)
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BN_CTX_end(ctx);
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BN_CTX_free(ctx);
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free(buf);
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return (ret);
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}
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static ECDH_METHOD openssl_ecdh_meth = {
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.name = "OpenSSL ECDH method",
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.compute_key = ecdh_compute_key
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};
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const ECDH_METHOD *
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ECDH_OpenSSL(void)
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{
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return &openssl_ecdh_meth;
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}
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/* replace w/ ecdh_compute_key() when ECDH_METHOD gets removed */
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int
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ossl_ecdh_compute_key(void *out, size_t outlen, const EC_POINT *pub_key,
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EC_KEY *eckey,
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void *(*KDF)(const void *in, size_t inlen, void *out, size_t *outlen))
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{
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ECDH_DATA *ecdh;
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if ((ecdh = ecdh_check(eckey)) == NULL)
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return 0;
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return ecdh->meth->compute_key(out, outlen, pub_key, eckey, KDF);
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}
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int
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ECDH_compute_key(void *out, size_t outlen, const EC_POINT *pub_key,
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EC_KEY *eckey,
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void *(*KDF)(const void *in, size_t inlen, void *out, size_t *outlen))
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{
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if (eckey->meth->compute_key != NULL)
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return eckey->meth->compute_key(out, outlen, pub_key, eckey, KDF);
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ECerror(EC_R_NOT_IMPLEMENTED);
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return 0;
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}
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