/*

   Unix SMB/CIFS implementation.

   Wrapper for gnutls hash and encryption functions

   Copyright (C) Stefan Metzmacher <metze@samba.org> 2007

   Copyright (C) Andrew Bartlett <abartlet@samba.org> 2009-2019

   Copyright (c) Andreas Schneider <asn@samba.org> 2019

   This program is free software; you can redistribute it and/or modify

   it under the terms of the GNU General Public License as published by

   the Free Software Foundation; either version 3 of the License, or

   (at your option) any later version.

   This program 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 General Public License for more details.

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

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

*/

/*

 * This (arcfour over data with a key combined from two inputs, one

 * the key another the confounder), is a common pattern in pre-AES

 * windows cryptography

 *

 * Some protocols put the confounder first, others second so both

 * parameters are named key_input here.

 *

 */

#include "includes.h"

#include "lib/util/data_blob.h"

#include <gnutls/gnutls.h>

#include <gnutls/crypto.h>

#include "gnutls_helpers.h"

#include "lib/util/memory.h"

int samba_gnutls_arcfour_confounded_md5(const DATA_BLOB *key_input1,

          const DATA_BLOB *key_input2,

          DATA_BLOB *data,

          enum samba_gnutls_direction encrypt)

{

  int rc;

  gnutls_hash_hd_t hash_hnd = NULL;

  uint8_t confounded_key[16];

  gnutls_cipher_hd_t cipher_hnd = NULL;

  gnutls_datum_t confounded_key_datum = {

    .data = confounded_key,

    .size = sizeof(confounded_key),

  };

  rc = gnutls_hash_init(&hash_hnd, GNUTLS_DIG_MD5);

  if (rc < 0) {

    return rc;

  }

  rc = gnutls_hash(hash_hnd, key_input1->data, key_input1->length);

  if (rc < 0) {

    gnutls_hash_deinit(hash_hnd, NULL);

    return rc;

  }

  rc = gnutls_hash(hash_hnd, key_input2->data, key_input2->length);

  if (rc < 0) {

    gnutls_hash_deinit(hash_hnd, NULL);

    return rc;

  }

  gnutls_hash_deinit(hash_hnd, confounded_key);

  rc = gnutls_cipher_init(&cipher_hnd,

        GNUTLS_CIPHER_ARCFOUR_128,

        &confounded_key_datum,

        NULL);

  if (rc < 0) {

    return rc;

  }

  if (encrypt == SAMBA_GNUTLS_ENCRYPT) {

    rc = gnutls_cipher_encrypt(cipher_hnd,

             data->data,

             data->length);

  } else {

    rc = gnutls_cipher_decrypt(cipher_hnd,

             data->data,

             data->length);

  }

  gnutls_cipher_deinit(cipher_hnd);

  ZERO_ARRAY(confounded_key);

  return rc;

}