GCC Code Coverage Report
Directory: ./ Exec Total Coverage
File: lib/libcrypto/ecdh/ech_key.c Lines: 39 64 60.9 %
Date: 2017-11-07 Branches: 23 40 57.5 %

Line Branch Exec Source
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/* $OpenBSD: ech_key.c,v 1.7 2017/01/29 17:49:23 beck 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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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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107
1279
	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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1279
	if ((ctx = BN_CTX_new()) == NULL)
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		goto err;
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1279
	BN_CTX_start(ctx);
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1279
	if ((x = BN_CTX_get(ctx)) == NULL)
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		goto err;
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1279
	if ((y = BN_CTX_get(ctx)) == NULL)
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		goto err;
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121
1279
	priv_key = EC_KEY_get0_private_key(ecdh);
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1279
	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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127
1279
	group = EC_KEY_get0_group(ecdh);
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1279
	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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133
1279
	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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138
1279
	if (EC_METHOD_get_field_type(EC_GROUP_method_of(group)) ==
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	    NID_X9_62_prime_field) {
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1159
		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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120
		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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156
1279
	buflen = ECDH_size(ecdh);
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1279
	len = BN_num_bytes(x);
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1279
	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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2378
	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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1279
	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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1279
	memset(buf, 0, buflen - len);
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1279
	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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1279
	if (KDF != NULL) {
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180
		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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180
		ret = outlen;
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180
	} else {
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		/* No KDF, just copy out the key and zero the rest. */
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1099
		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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1099
		memcpy(out, buf, outlen);
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1099
		ret = outlen;
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	}
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err:
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1279
	EC_POINT_free(tmp);
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1279
	if (ctx)
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1279
		BN_CTX_end(ctx);
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1279
	BN_CTX_free(ctx);
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1279
	free(buf);
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1279
	return (ret);
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1279
}
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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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204
	return &openssl_ecdh_meth;
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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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2558
	ECDH_DATA *ecdh = ecdh_check(eckey);
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1279
	if (ecdh == NULL)
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		return 0;
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1279
	return ecdh->meth->compute_key(out, outlen, pub_key, eckey, KDF);
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1279
}