yuzu/externals/libressl/crypto/dh/dh_key.c

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2020-12-28 19:15:37 +04:00
/* $OpenBSD: dh_key.c,v 1.36 2018/11/12 17:39:17 tb Exp $ */
/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
* All rights reserved.
*
* This package is an SSL implementation written
* by Eric Young (eay@cryptsoft.com).
* The implementation was written so as to conform with Netscapes SSL.
*
* This library is free for commercial and non-commercial use as long as
* the following conditions are aheared to. The following conditions
* apply to all code found in this distribution, be it the RC4, RSA,
* lhash, DES, etc., code; not just the SSL code. The SSL documentation
* included with this distribution is covered by the same copyright terms
* except that the holder is Tim Hudson (tjh@cryptsoft.com).
*
* Copyright remains Eric Young's, and as such any Copyright notices in
* the code are not to be removed.
* If this package is used in a product, Eric Young should be given attribution
* as the author of the parts of the library used.
* This can be in the form of a textual message at program startup or
* in documentation (online or textual) provided with the package.
*
* 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 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 acknowledgement:
* "This product includes cryptographic software written by
* Eric Young (eay@cryptsoft.com)"
* The word 'cryptographic' can be left out if the rouines from the library
* being used are not cryptographic related :-).
* 4. If you include any Windows specific code (or a derivative thereof) from
* the apps directory (application code) you must include an acknowledgement:
* "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
*
* THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
* ANY EXPRESS 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 AUTHOR OR 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.
*
* The licence and distribution terms for any publically available version or
* derivative of this code cannot be changed. i.e. this code cannot simply be
* copied and put under another distribution licence
* [including the GNU Public Licence.]
*/
#include <stdio.h>
#include <openssl/bn.h>
#include <openssl/dh.h>
#include <openssl/err.h>
#include "bn_lcl.h"
static int generate_key(DH *dh);
static int compute_key(unsigned char *key, const BIGNUM *pub_key, DH *dh);
static int dh_bn_mod_exp(const DH *dh, BIGNUM *r, const BIGNUM *a,
const BIGNUM *p, const BIGNUM *m, BN_CTX *ctx, BN_MONT_CTX *m_ctx);
static int dh_init(DH *dh);
static int dh_finish(DH *dh);
int
DH_generate_key(DH *dh)
{
return dh->meth->generate_key(dh);
}
int
DH_compute_key(unsigned char *key, const BIGNUM *pub_key, DH *dh)
{
return dh->meth->compute_key(key, pub_key, dh);
}
static DH_METHOD dh_ossl = {
.name = "OpenSSL DH Method",
.generate_key = generate_key,
.compute_key = compute_key,
.bn_mod_exp = dh_bn_mod_exp,
.init = dh_init,
.finish = dh_finish,
};
const DH_METHOD *
DH_OpenSSL(void)
{
return &dh_ossl;
}
static int
generate_key(DH *dh)
{
int ok = 0;
unsigned l;
BN_CTX *ctx;
BN_MONT_CTX *mont = NULL;
BIGNUM *pub_key = NULL, *priv_key = NULL, *two = NULL;
if (BN_num_bits(dh->p) > OPENSSL_DH_MAX_MODULUS_BITS) {
DHerror(DH_R_MODULUS_TOO_LARGE);
return 0;
}
ctx = BN_CTX_new();
if (ctx == NULL)
goto err;
if ((priv_key = dh->priv_key) == NULL) {
if ((priv_key = BN_new()) == NULL)
goto err;
}
if ((pub_key = dh->pub_key) == NULL) {
if ((pub_key = BN_new()) == NULL)
goto err;
}
if (dh->flags & DH_FLAG_CACHE_MONT_P) {
mont = BN_MONT_CTX_set_locked(&dh->method_mont_p,
CRYPTO_LOCK_DH, dh->p, ctx);
if (!mont)
goto err;
}
if (dh->priv_key == NULL) {
if (dh->q) {
if ((two = BN_new()) == NULL)
goto err;
if (!BN_add(two, BN_value_one(), BN_value_one()))
goto err;
if (!bn_rand_interval(priv_key, two, dh->q))
goto err;
} else {
/* secret exponent length */
l = dh->length ? dh->length : BN_num_bits(dh->p) - 1;
if (!BN_rand(priv_key, l, 0, 0))
goto err;
}
}
if (!dh->meth->bn_mod_exp(dh, pub_key, dh->g, priv_key, dh->p, ctx,
mont))
goto err;
dh->pub_key = pub_key;
dh->priv_key = priv_key;
ok = 1;
err:
if (ok != 1)
DHerror(ERR_R_BN_LIB);
if (dh->pub_key == NULL)
BN_free(pub_key);
if (dh->priv_key == NULL)
BN_free(priv_key);
BN_CTX_free(ctx);
BN_free(two);
return ok;
}
static int
compute_key(unsigned char *key, const BIGNUM *pub_key, DH *dh)
{
BN_CTX *ctx = NULL;
BN_MONT_CTX *mont = NULL;
BIGNUM *tmp;
int ret = -1;
int check_result;
if (BN_num_bits(dh->p) > OPENSSL_DH_MAX_MODULUS_BITS) {
DHerror(DH_R_MODULUS_TOO_LARGE);
goto err;
}
ctx = BN_CTX_new();
if (ctx == NULL)
goto err;
BN_CTX_start(ctx);
if ((tmp = BN_CTX_get(ctx)) == NULL)
goto err;
if (dh->priv_key == NULL) {
DHerror(DH_R_NO_PRIVATE_VALUE);
goto err;
}
if (dh->flags & DH_FLAG_CACHE_MONT_P) {
mont = BN_MONT_CTX_set_locked(&dh->method_mont_p,
CRYPTO_LOCK_DH, dh->p, ctx);
BN_set_flags(dh->priv_key, BN_FLG_CONSTTIME);
if (!mont)
goto err;
}
if (!DH_check_pub_key(dh, pub_key, &check_result) || check_result) {
DHerror(DH_R_INVALID_PUBKEY);
goto err;
}
if (!dh->meth->bn_mod_exp(dh, tmp, pub_key, dh->priv_key, dh->p, ctx,
mont)) {
DHerror(ERR_R_BN_LIB);
goto err;
}
ret = BN_bn2bin(tmp, key);
err:
if (ctx != NULL) {
BN_CTX_end(ctx);
BN_CTX_free(ctx);
}
return ret;
}
static int
dh_bn_mod_exp(const DH *dh, BIGNUM *r, const BIGNUM *a, const BIGNUM *p,
const BIGNUM *m, BN_CTX *ctx, BN_MONT_CTX *m_ctx)
{
return BN_mod_exp_mont_ct(r, a, p, m, ctx, m_ctx);
}
static int
dh_init(DH *dh)
{
dh->flags |= DH_FLAG_CACHE_MONT_P;
return 1;
}
static int
dh_finish(DH *dh)
{
BN_MONT_CTX_free(dh->method_mont_p);
return 1;
}