<?php

define('YK_SEC_NORMAL_USERNAME', 1);

define('YK_SEC_NORMAL_PASSWORD', 2);

define('YK_SEC_ELEV_USERNAME', 4);

define('YK_SEC_ELEV_PASSWORD', 8);

define('YK_SEC_ALLOW_NO_OTP', 16);

define('YK_DEFAULT_VERIFY_URL', 'http://api.yubico.com/wsapi/verify');

function generate_yubikey_field($name = 'yubikey_otp', $value = false)

{

  global $lang;

  $fid = substr(sha1(microtime() . mt_rand()), 0, 12);

  $class = $value ? 'wasfull' : 'wasempty';

  $html = '<input id="yubifield' . $fid . '" class="' . $class . '" type="hidden" name="' . $name . '" value="' . ( is_string($value) ? $value : '' ) . '" />';

  if ( $value )

  {

    $html .= '<span id="yubistat' . $fid . '" class="yubikey_status enrolled">' . $lang->get('yubiauth_ctl_status_enrolled') . '</span>';

    $atext = $lang->get('yubiauth_ctl_btn_change_key');

    $classadd = ' abutton_green';

  }

  else

  {

    $html .= '<span id="yubistat' . $fid . '" class="yubikey_status empty">' . $lang->get('yubiauth_ctl_status_empty') . '</span>';

    $atext = $lang->get('yubiauth_ctl_btn_enroll');

    $classadd = '';

  }

  $html .= ' <a class="abutton' . $classadd . ' yubikey_enroll" onclick="yk_mb_init(\'yubifield' . $fid . '\', \'yubistat' . $fid . '\'); return false;" href="#enroll">' . $atext . '</a>';

  if ( $value )

  {

    $html .= ' <a class="abutton abutton_red yubikey_enroll" onclick="yk_clear(\'yubifield' . $fid . '\', \'yubistat' . $fid . '\'); return false;" href="#enroll">'

             . $lang->get('yubiauth_ctl_btn_clear') .

             '</a>';

  }

  $html = '<noscript><input type="text" name="' . $name . '" class="yubikey_noscript" value="' . ( is_string($value) ? $value : '' ) . '" /> </noscript>'

          . $html; // '<script type="text/javascript">document.write(unescape("' . rawurlencode($html) . '"));</script>';

  return $html;

}

function yubikey_validate_otp($otp)

{

  $api_key = getConfig('yubikey_api_key');

  $api_id  = getConfig('yubikey_api_key_id');

  if ( !$api_key || !$api_id )

  {

    return array(

        'success' => false,

        'error' => 'missing_api_key'

      );

  }

  if ( !preg_match('/^[cbdefghijklnrtuv]{44}$/', $otp) )

  {

    return array(

        'success' => false,

        'error' => 'otp_invalid_chars'

      );

  }

  // make HTTP request

  require_once( ENANO_ROOT . '/includes/http.php' );

  $auth_url = getConfig('yubikey_auth_server', YK_DEFAULT_VERIFY_URL);

  $auth_url = preg_replace('#^https?://#i', '', $auth_url);

  if ( !preg_match('#^(\[?[a-z0-9-:]+(?:\.[a-z0-9-:]+\]?)*)(?::([0-9]+))?(/.*)$#U', $auth_url, $match) )

  {

    return array(

        'success' => false,

        'error' => 'invalid_auth_url'

      );

  }

  $auth_server =& $match[1];

  $auth_port = ( !empty($match[2]) ) ? intval($match[2]) : 80;

  $auth_uri =& $match[3];

  try

  {

    $req = new Request_HTTP($auth_server, $auth_uri, 'GET', $auth_port);

    $req->add_get('id', strval($api_id));

    $req->add_get('otp', $otp);

    $req->add_get('h', yubikey_sign($req->parms_get));

    $response = $req->get_response_body();

  }

  catch ( Exception $e )

  {

    return array(

        'success' => false,

        'error' => 'http_failed',

        'http_error' => $e->getMessage()

      );

  }

  if ( $req->response_code != HTTP_OK )

  {

    return array(

        'success' => false,

        'error' => 'http_response_error'

      );

  }

  $response = trim($response);

  if ( !preg_match_all('/^([a-z0-9_]+)=(.*?)\r?$/m', $response, $matches) )

  {

    return array(

        'success' => false,

        'error' => 'malformed_response'

      );

  }

  $response = array();

  foreach ( $matches[0] as $i => $_ )

  {

    $response[$matches[1][$i]] = $matches[2][$i];

  }

  // make sure we have a status

  if ( !isset($response['status']) )

  {

    return array(

        'success' => false,

        'error' => 'response_missing_status'

      );

  }

  // verify response signature

  // MISSING_PARAMETER is the ONLY situation under which an unsigned response is acceptable

  if ( $response['status'] !== 'MISSING_PARAMETER' )

  {

    if ( !isset($response['h']) )

    {

      return array(

          'success' => false,

          'error' => 'response_missing_sig'

        );

    }

    if ( yubikey_sign($response) !== $response['h'] )

    {

      return array(

          'success' => false,

          'error' => 'response_invalid_sig'

        );

    }

  }

  if ( $response['status'] === 'OK' )

  {

    if ( yubikey_verify_timestamp($response['t']) )

    {

      return array(

          'success' => true

        );

    }

    else

    {

      return array(

          'success' => false,

          'error' => 'timestamp_check_failed'

        );

    }

  }

  else

  {

    return array(

        'success' => false,

        'error' => strtolower("response_{$response['status']}")

      );

  }

}

function yubikey_sign($arr)

{

  static $api_key = false;

  ksort($arr);

  if ( !$api_key )

  {

    $api_key = getConfig('yubikey_api_key');

    $api_key = hexencode(base64_decode($api_key), '', '');

  }

  if ( isset($arr['h']) )

    unset($arr['h']);

  $req = array();

  foreach ( $arr as $key => $val )

  {

    $req[] = "$key=$val";

  }

  $req = implode('&', $req);

  $sig = hmac_sha1($req, $api_key);

  $sig = hexdecode($sig);

  $sig = base64_encode($sig);

  return $sig;

}

/**

 * Validate the timestamp returned in a Yubico API response. Borrowed from Drupal and backported for friendliness with earlier versions of PHP.

 * @param string Yubico timestamp

 * @return bool True if valid, false otherwise

 */

function yubikey_verify_timestamp($timestamp)

{

  $tolerance = intval(getConfig('yubikey_api_ts_tolerance', 150));

  $now = time();

  $timestamp = preg_replace('/Z[0-9]{3,5}$/', '', $timestamp);

  $timestamp_seconds = strtotime($timestamp);

  if ( !$timestamp || !$now )

  {

    return false;

  }

  if ( ( $timestamp_seconds + $tolerance ) > $now && ( $timestamp_seconds - $tolerance ) < $now )

  {

    return true;

  }

  return false;

}

$plugins->attachHook('compile_template', 'yubikey_attach_headers($this);');

function yubikey_attach_headers(&$template)

{

  global $db, $session, $paths, $template, $plugins; // Common objects

  if ( getConfig('yubikey_enable', '1') != '1' )

    return true;

  $template->add_header('<script type="text/javascript" src="' . scriptPath . '/plugins/yubikey/yubikey.js"></script>');

  $template->add_header('<link rel="stylesheet" type="text/css" href="' . scriptPath . '/plugins/yubikey/yubikey.css" />');

  // config option for all users have yubikey

  $user_flags = 0;

  $yk_enabled = 0;

  if ( $session->user_logged_in )

  {

    if ( !$q )

      $db->_die();

    list($yk_enabled, $user_flags) = $db->fetchrow_num();

    $db->free_result();

  }

  $template->add_header('<script type="text/javascript">var yk_reg_require_otp = ' . getConfig('yubikey_reg_require_otp', '0') . '; var yk_user_enabled = ' . $yk_enabled . '; var yk_user_flags = ' . $user_flags . ';</script>');

}