/*

 * Copyright (C) 2000-2012 Free Software Foundation, Inc.

 * Copyright (C) 2017 Red Hat, Inc.

 *

 * Author: Nikos Mavrogiannopoulos

 *

 * This file is part of GnuTLS.

 *

 * The GnuTLS is free software; you can redistribute it and/or

 * modify it under the terms of the GNU Lesser General Public License

 * as published by the Free Software Foundation; either version 2.1 of

 * the License, or (at your option) any later version.

 *

 * This library is distributed in the hope that it will be useful, but

 * WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

 * Lesser General Public License for more details.

 *

 * You should have received a copy of the GNU Lesser General Public License

 * along with this program.  If not, see <https://www.gnu.org/licenses/>

 *

 */

/* This file contains everything for the Ephemeral Diffie-Hellman

 * (DHE) key exchange.  This is used in the handshake procedure of the

 * certificate authentication.

 */

#include "gnutls_int.h"

#include "auth.h"

#include "errors.h"

#include "dh.h"

#include "num.h"

#include "tls-sig.h"

#include <datum.h>

#include <algorithms.h>

#include <auth/cert.h>

#include <x509.h>

#include <state.h>

#include <auth/dh_common.h>

#include <auth/ecdhe.h>

static int gen_dhe_server_kx(gnutls_session_t, gnutls_buffer_st *);

static int proc_dhe_server_kx(gnutls_session_t, uint8_t *, size_t);

static int proc_dhe_client_kx(gnutls_session_t, uint8_t *, size_t);

#ifdef ENABLE_DHE

const mod_auth_st dhe_rsa_auth_struct = {

  "DHE_RSA",

  _gnutls_gen_cert_server_crt,

  _gnutls_gen_cert_client_crt,

  gen_dhe_server_kx,

  _gnutls_gen_dh_common_client_kx,

  _gnutls_gen_cert_client_crt_vrfy, /* gen client cert vrfy */

  _gnutls_gen_cert_server_cert_req, /* server cert request */

  _gnutls_proc_crt,

  _gnutls_proc_crt,

  proc_dhe_server_kx,

  proc_dhe_client_kx,

  _gnutls_proc_cert_client_crt_vrfy,  /* proc client cert vrfy */

  _gnutls_proc_cert_cert_req  /* proc server cert request */

};

const mod_auth_st dhe_dss_auth_struct = {

  "DHE_DSS",

  _gnutls_gen_cert_server_crt,

  _gnutls_gen_cert_client_crt,

  gen_dhe_server_kx,

  _gnutls_gen_dh_common_client_kx,

  _gnutls_gen_cert_client_crt_vrfy, /* gen client cert vrfy */

  _gnutls_gen_cert_server_cert_req, /* server cert request */

  _gnutls_proc_crt,

  _gnutls_proc_crt,

  proc_dhe_server_kx,

  proc_dhe_client_kx,

  _gnutls_proc_cert_client_crt_vrfy,  /* proc client cert vrfy */

  _gnutls_proc_cert_cert_req  /* proc server cert request */

};

#endif

static int gen_dhe_server_kx(gnutls_session_t session, gnutls_buffer_st * data)

{

  int ret = 0;

  gnutls_certificate_credentials_t cred;

  unsigned sig_pos;

  cred = (gnutls_certificate_credentials_t)

      _gnutls_get_cred(session, GNUTLS_CRD_CERTIFICATE);

  if (cred == NULL) {

    gnutls_assert();

    return GNUTLS_E_INSUFFICIENT_CREDENTIALS;

  }

  if ((ret = _gnutls_auth_info_init(session, GNUTLS_CRD_CERTIFICATE,

            sizeof(cert_auth_info_st), 1)) < 0) {

    gnutls_assert();

    return ret;

  }

  ret =

      _gnutls_figure_dh_params(session, cred->dh_params,

             cred->params_func, cred->dh_sec_param);

  if (ret < 0) {

    return gnutls_assert_val(ret);

  }

  sig_pos = data->length;

  ret = _gnutls_dh_common_print_server_kx(session, data);

  if (ret < 0) {

    gnutls_assert();

    return ret;

  }

  /* Generate the signature. */

  return _gnutls_gen_dhe_signature(session, data, &data->data[sig_pos],

           data->length - sig_pos);

}

static int

proc_dhe_server_kx(gnutls_session_t session, uint8_t * data, size_t _data_size)

{

  gnutls_datum_t vdata;

  int ret;

  ret = _gnutls_proc_dh_common_server_kx(session, data, _data_size);

  if (ret < 0)

    return gnutls_assert_val(ret);

  vdata.data = data;

  vdata.size = ret;

  return _gnutls_proc_dhe_signature(session, data + ret,

            _data_size - ret, &vdata);

}

static int

proc_dhe_client_kx(gnutls_session_t session, uint8_t * data, size_t _data_size)

{

  return _gnutls_proc_dh_common_client_kx(session, data, _data_size,

            NULL);

}