GCC Code Coverage Report
Directory: ./ Exec Total Coverage
File: lib/libcrypto/dh/dh_key.c Lines: 60 74 81.1 %
Date: 2017-11-07 Branches: 32 65 49.2 %

Line Branch Exec Source
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/* $OpenBSD: dh_key.c,v 1.27 2017/01/29 17:49:22 beck Exp $ */
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/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
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 * All rights reserved.
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 *
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 * This package is an SSL implementation written
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 * by Eric Young (eay@cryptsoft.com).
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 * The implementation was written so as to conform with Netscapes SSL.
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 *
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 * This library is free for commercial and non-commercial use as long as
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 * the following conditions are aheared to.  The following conditions
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 * apply to all code found in this distribution, be it the RC4, RSA,
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 * lhash, DES, etc., code; not just the SSL code.  The SSL documentation
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 * included with this distribution is covered by the same copyright terms
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 * except that the holder is Tim Hudson (tjh@cryptsoft.com).
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 *
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 * Copyright remains Eric Young's, and as such any Copyright notices in
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 * the code are not to be removed.
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 * If this package is used in a product, Eric Young should be given attribution
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 * as the author of the parts of the library used.
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 * This can be in the form of a textual message at program startup or
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 * in documentation (online or textual) provided with the package.
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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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 * 1. Redistributions of source code must retain the copyright
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 *    notice, this list of conditions and the following disclaimer.
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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 the
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 *    documentation and/or other materials provided with the distribution.
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 * 3. All advertising materials mentioning features or use of this software
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 *    must display the following acknowledgement:
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 *    "This product includes cryptographic software written by
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 *     Eric Young (eay@cryptsoft.com)"
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 *    The word 'cryptographic' can be left out if the rouines from the library
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 *    being used are not cryptographic related :-).
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 * 4. If you include any Windows specific code (or a derivative thereof) from
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 *    the apps directory (application code) you must include an acknowledgement:
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 *    "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
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 *
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 * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
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 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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 * SUCH DAMAGE.
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 *
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 * The licence and distribution terms for any publically available version or
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 * derivative of this code cannot be changed.  i.e. this code cannot simply be
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 * copied and put under another distribution licence
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 * [including the GNU Public Licence.]
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 */
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#include <stdio.h>
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#include <openssl/bn.h>
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#include <openssl/dh.h>
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#include <openssl/err.h>
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#include "bn_lcl.h"
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static int generate_key(DH *dh);
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static int compute_key(unsigned char *key, const BIGNUM *pub_key, DH *dh);
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static int dh_bn_mod_exp(const DH *dh, BIGNUM *r, const BIGNUM *a,
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	    const BIGNUM *p, const BIGNUM *m, BN_CTX *ctx, BN_MONT_CTX *m_ctx);
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static int dh_init(DH *dh);
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static int dh_finish(DH *dh);
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int
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DH_generate_key(DH *dh)
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{
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736
	return dh->meth->generate_key(dh);
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}
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int
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DH_compute_key(unsigned char *key, const BIGNUM *pub_key, DH *dh)
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{
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712
	return dh->meth->compute_key(key, pub_key, dh);
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}
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static DH_METHOD dh_ossl = {
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	.name = "OpenSSL DH Method",
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	.generate_key = generate_key,
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	.compute_key = compute_key,
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	.bn_mod_exp = dh_bn_mod_exp,
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	.init = dh_init,
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	.finish = dh_finish,
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};
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const DH_METHOD *
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DH_OpenSSL(void)
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{
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2838
	return &dh_ossl;
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}
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static int
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generate_key(DH *dh)
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{
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	int ok = 0;
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	int generate_new_key = 0;
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	unsigned l;
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	BN_CTX *ctx;
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	BN_MONT_CTX *mont = NULL;
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	BIGNUM *pub_key = NULL, *priv_key = NULL;
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736
	ctx = BN_CTX_new();
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368
	if (ctx == NULL)
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		goto err;
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115
368
	if (dh->priv_key == NULL) {
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264
		priv_key = BN_new();
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264
		if (priv_key == NULL)
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			goto err;
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		generate_new_key = 1;
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264
	} else
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		priv_key = dh->priv_key;
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123
368
	if (dh->pub_key == NULL) {
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		pub_key = BN_new();
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368
		if (pub_key == NULL)
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			goto err;
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	} else
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		pub_key = dh->pub_key;
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130
368
	if (dh->flags & DH_FLAG_CACHE_MONT_P) {
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736
		mont = BN_MONT_CTX_set_locked(&dh->method_mont_p,
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368
		    CRYPTO_LOCK_DH, dh->p, ctx);
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368
		if (!mont)
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			goto err;
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	}
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137
368
	if (generate_new_key) {
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264
		if (dh->q) {
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			do {
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				if (!BN_rand_range(priv_key, dh->q))
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					goto err;
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			} while (BN_is_zero(priv_key) || BN_is_one(priv_key));
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		} else {
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			/* secret exponent length */
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792
			l = dh->length ? dh->length : BN_num_bits(dh->p) - 1;
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264
			if (!BN_rand(priv_key, l, 0, 0))
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				goto err;
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		}
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	}
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151
	{
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368
		BIGNUM prk;
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154
368
		BN_init(&prk);
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368
		BN_with_flags(&prk, priv_key, BN_FLG_CONSTTIME);
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157
368
		if (!dh->meth->bn_mod_exp(dh, pub_key, dh->g, &prk, dh->p, ctx,
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		    mont)) {
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			goto err;
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		}
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1472
	}
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163
368
	dh->pub_key = pub_key;
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368
	dh->priv_key = priv_key;
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368
	ok = 1;
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err:
167
368
	if (ok != 1)
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		DHerror(ERR_R_BN_LIB);
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170

736
	if (pub_key != NULL && dh->pub_key == NULL)
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		BN_free(pub_key);
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736
	if (priv_key != NULL && dh->priv_key == NULL)
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		BN_free(priv_key);
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368
	BN_CTX_free(ctx);
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368
	return ok;
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368
}
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static int
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compute_key(unsigned char *key, const BIGNUM *pub_key, DH *dh)
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{
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	BN_CTX *ctx = NULL;
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	BN_MONT_CTX *mont = NULL;
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	BIGNUM *tmp;
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	int ret = -1;
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712
        int check_result;
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187
356
	if (BN_num_bits(dh->p) > OPENSSL_DH_MAX_MODULUS_BITS) {
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		DHerror(DH_R_MODULUS_TOO_LARGE);
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		goto err;
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	}
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192
356
	ctx = BN_CTX_new();
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356
	if (ctx == NULL)
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		goto err;
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356
	BN_CTX_start(ctx);
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356
	if ((tmp = BN_CTX_get(ctx)) == NULL)
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		goto err;
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199
356
	if (dh->priv_key == NULL) {
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		DHerror(DH_R_NO_PRIVATE_VALUE);
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		goto err;
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	}
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204
356
	if (dh->flags & DH_FLAG_CACHE_MONT_P) {
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712
		mont = BN_MONT_CTX_set_locked(&dh->method_mont_p,
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356
		    CRYPTO_LOCK_DH, dh->p, ctx);
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208
356
		BN_set_flags(dh->priv_key, BN_FLG_CONSTTIME);
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210
356
		if (!mont)
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			goto err;
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	}
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214
356
        if (!DH_check_pub_key(dh, pub_key, &check_result) || check_result) {
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		DHerror(DH_R_INVALID_PUBKEY);
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		goto err;
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	}
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219
356
	if (!dh->meth->bn_mod_exp(dh, tmp, pub_key, dh->priv_key, dh->p, ctx,
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	    mont)) {
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		DHerror(ERR_R_BN_LIB);
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		goto err;
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	}
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225
356
	ret = BN_bn2bin(tmp, key);
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err:
227
356
	if (ctx != NULL) {
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356
		BN_CTX_end(ctx);
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356
		BN_CTX_free(ctx);
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356
	}
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356
	return ret;
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356
}
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234
static int
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dh_bn_mod_exp(const DH *dh, BIGNUM *r, const BIGNUM *a, const BIGNUM *p,
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    const BIGNUM *m, BN_CTX *ctx, BN_MONT_CTX *m_ctx)
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{
238
1448
	return BN_mod_exp_mont_ct(r, a, p, m, ctx, m_ctx);
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}
240
241
static int
242
dh_init(DH *dh)
243
{
244
4708
	dh->flags |= DH_FLAG_CACHE_MONT_P;
245
2354
	return 1;
246
}
247
248
static int
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dh_finish(DH *dh)
250
{
251
2344
	BN_MONT_CTX_free(dh->method_mont_p);
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1172
	return 1;
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}