dh: Add OpenSSL libcrypto specific DH implementation
Signed-off-by: Simo Sorce <simo@redhat.com> Reviewed-by: Anderson Toshiyuki Sasaki <ansasaki@redhat.com> Reviewed-by: Andreas Schneider <asn@cryptomilk.org>
Этот коммит содержится в:
Simo Sorce
Andreas Schneider
родитель
7551857d08
Коммит
33399e52f0
@ -218,7 +218,7 @@ else (WITH_GCRYPT)
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pki_crypto.c
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ecdh_crypto.c
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libcrypto.c
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dh_key.c
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dh_crypto.c
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)
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if(OPENSSL_VERSION VERSION_LESS "1.1.0")
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set(libssh_SRCS ${libssh_SRCS} libcrypto-compat.c)
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261
src/dh_crypto.c
Обычный файл
261
src/dh_crypto.c
Обычный файл
@ -0,0 +1,261 @@
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/*
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* This file is part of the SSH Library
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*
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* Copyright (c) 2019 by Simo Sorce - Red Hat, Inc.
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*
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* The SSH Library is free software; you can redistribute it and/or modify
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* it under the terms of the GNU Lesser General Public License as published by
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* the Free Software Foundation; either version 2.1 of the License, or (at your
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* option) any later version.
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*
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* The SSH Library is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
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* or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
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* License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public License
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* along with the SSH Library; see the file COPYING. If not, write to
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* the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
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* MA 02111-1307, USA.
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*/
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#include "config.h"
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#include "libssh/session.h"
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#include "libssh/dh.h"
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#include "libssh/buffer.h"
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#include "libssh/ssh2.h"
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#include "libssh/pki.h"
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#include "libssh/bignum.h"
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#include "openssl/crypto.h"
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#include "openssl/dh.h"
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extern bignum ssh_dh_generator;
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extern bignum ssh_dh_group1;
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extern bignum ssh_dh_group14;
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extern bignum ssh_dh_group16;
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extern bignum ssh_dh_group18;
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struct dh_ctx {
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DH *keypair[2];
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};
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int ssh_dh_keypair_get_keys(struct dh_ctx *ctx, int peer,
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const_bignum *priv, const_bignum *pub)
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{
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if (((peer != DH_CLIENT_KEYPAIR) && (peer != DH_SERVER_KEYPAIR)) ||
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((priv == NULL) && (pub == NULL)) || (ctx == NULL) ||
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(ctx->keypair[peer] == NULL)) {
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return SSH_ERROR;
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}
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DH_get0_key(ctx->keypair[peer], pub, priv);
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if (priv && (*priv == NULL || bignum_num_bits(*priv) == 0)) {
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return SSH_ERROR;
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}
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if (pub && (*pub == NULL || bignum_num_bits(*pub) == 0)) {
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return SSH_ERROR;
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}
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return SSH_OK;
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}
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int ssh_dh_keypair_set_keys(struct dh_ctx *ctx, int peer,
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const bignum priv, const bignum pub)
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{
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bignum priv_key = NULL;
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bignum pub_key = NULL;
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if (((peer != DH_CLIENT_KEYPAIR) && (peer != DH_SERVER_KEYPAIR)) ||
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((priv == NULL) && (pub == NULL)) || (ctx == NULL) ||
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(ctx->keypair[peer] == NULL)) {
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return SSH_ERROR;
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}
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if (priv) {
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priv_key = BN_dup(priv);
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}
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if (pub) {
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pub_key = BN_dup(pub);
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}
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(void)DH_set0_key(ctx->keypair[peer], pub_key, priv_key);
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return SSH_OK;
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}
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int ssh_dh_get_parameters(struct dh_ctx *ctx,
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const_bignum *modulus, const_bignum *generator)
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{
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if (ctx == NULL || ctx->keypair[0] == NULL) {
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return SSH_ERROR;
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}
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DH_get0_pqg(ctx->keypair[0], modulus, NULL, generator);
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return SSH_OK;
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}
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int ssh_dh_set_parameters(struct dh_ctx *ctx,
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const bignum modulus, const bignum generator)
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{
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int rc;
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if ((ctx == NULL) || (modulus == NULL) || (generator == NULL)) {
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return SSH_ERROR;
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}
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for (int i = 0; i < 2; i++) {
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bignum p = NULL;
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bignum g = NULL;
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/* when setting modulus or generator,
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* make sure to invalidate existing keys */
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DH_free(ctx->keypair[i]);
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ctx->keypair[i] = DH_new();
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if (ctx->keypair[i] == NULL) {
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rc = SSH_ERROR;
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goto done;
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}
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p = BN_dup(modulus);
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g = BN_dup(generator);
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rc = DH_set0_pqg(ctx->keypair[i], p, NULL, g);
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if (rc != 1) {
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BN_free(p);
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BN_free(g);
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rc = SSH_ERROR;
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goto done;
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}
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}
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rc = SSH_OK;
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done:
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if (rc != SSH_OK) {
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DH_free(ctx->keypair[0]);
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DH_free(ctx->keypair[1]);
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ctx->keypair[0] = NULL;
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ctx->keypair[1] = NULL;
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}
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return rc;
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}
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/**
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* @internal
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* @brief allocate and initialize ephemeral values used in dh kex
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*/
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int ssh_dh_init_common(struct ssh_crypto_struct *crypto)
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{
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struct dh_ctx *ctx;
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int rc;
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ctx = calloc(1, sizeof(*ctx));
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if (ctx == NULL) {
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return SSH_ERROR;
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}
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crypto->dh_ctx = ctx;
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switch (crypto->kex_type) {
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case SSH_KEX_DH_GROUP1_SHA1:
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rc = ssh_dh_set_parameters(ctx, ssh_dh_group1, ssh_dh_generator);
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break;
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case SSH_KEX_DH_GROUP14_SHA1:
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rc = ssh_dh_set_parameters(ctx, ssh_dh_group14, ssh_dh_generator);
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break;
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case SSH_KEX_DH_GROUP16_SHA512:
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rc = ssh_dh_set_parameters(ctx, ssh_dh_group16, ssh_dh_generator);
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break;
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case SSH_KEX_DH_GROUP18_SHA512:
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rc = ssh_dh_set_parameters(ctx, ssh_dh_group18, ssh_dh_generator);
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break;
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default:
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rc = SSH_OK;
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break;
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}
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if (rc != SSH_OK) {
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ssh_dh_cleanup(crypto);
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}
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return rc;
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}
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void ssh_dh_cleanup(struct ssh_crypto_struct *crypto)
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{
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if (crypto->dh_ctx != NULL) {
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DH_free(crypto->dh_ctx->keypair[0]);
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DH_free(crypto->dh_ctx->keypair[1]);
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crypto->dh_ctx = NULL;
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}
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}
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/** @internal
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* @brief generates a secret DH parameter of at least DH_SECURITY_BITS
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* security as well as the corresponding public key.
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* @param[out] parms a dh_ctx that will hold the new keys.
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* @param peer Select either client or server key storage. Valid values are:
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* DH_CLIENT_KEYPAIR or DH_SERVER_KEYPAIR
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*
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* @return SSH_OK on success, SSH_ERROR on error
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*/
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int ssh_dh_keypair_gen_keys(struct dh_ctx *dh_ctx, int peer)
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{
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int rc;
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if ((dh_ctx == NULL) || (dh_ctx->keypair[peer] == NULL)) {
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return SSH_ERROR;
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}
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rc = DH_generate_key(dh_ctx->keypair[peer]);
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if (rc != 1) {
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return SSH_ERROR;
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}
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return SSH_OK;
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}
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/** @internal
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* @brief generates a shared secret between the local peer and the remote
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* peer. The local peer must have been initialized using either the
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* ssh_dh_keypair_gen_keys() function or by seetting manually both
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* the private and public keys. The remote peer only needs to have
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* the remote's peer public key set.
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* @param[in] local peer identifier (DH_CLIENT_KEYPAIR or DH_SERVER_KEYPAIR)
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* @param[in] remote peer identifier (DH_CLIENT_KEYPAIR or DH_SERVER_KEYPAIR)
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* @param[out] dest a new bignum with the shared secret value is returned.
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* @return SSH_OK on success, SSH_ERROR on error
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*/
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int ssh_dh_compute_shared_secret(struct dh_ctx *dh_ctx, int local, int remote,
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bignum *dest)
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{
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unsigned char *kstring = NULL;
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const_bignum pub_key = NULL;
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int klen, rc;
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if ((dh_ctx == NULL) ||
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(dh_ctx->keypair[local] == NULL) ||
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(dh_ctx->keypair[remote] == NULL)) {
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return SSH_ERROR;
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}
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kstring = malloc(DH_size(dh_ctx->keypair[local]));
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if (kstring == NULL) {
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rc = SSH_ERROR;
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goto done;
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}
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rc = ssh_dh_keypair_get_keys(dh_ctx, remote, NULL, &pub_key);
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if (rc != SSH_OK) {
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rc = SSH_ERROR;
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goto done;
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}
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klen = DH_compute_key(kstring, pub_key, dh_ctx->keypair[local]);
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if (klen == -1) {
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rc = SSH_ERROR;
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goto done;
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}
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*dest = BN_bin2bn(kstring, klen, NULL);
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if (*dest == NULL) {
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rc = SSH_ERROR;
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goto done;
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}
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rc = SSH_OK;
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done:
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free(kstring);
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return rc;
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}
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