<?PHP
// $Id: phpids.module,v 1.8.4.2.2.13 2009-11-17 12:42:14 gos77 Exp $

/**
 * @file
 *
 * phpids tries to identify attacks (xss, sql-injections ...) and
 * uses an external package called PHPIDS (php-ids.org) to scan 
 * incoming and POST & GET variables. It's able to log, redirect 
 * or send out mails to warn the site administrator.
 */

/**
 * Implementation of hook_menu().
 */
function phpids_menu() {
  $items['admin/settings/logging/phpids'] = array(
    'title' => 'PHPIDS Settings',
    'description' => t('Configure PHPIDS settings and levels'),
    'page callback' => 'drupal_get_form',
    'page arguments' => array('phpids_admin_settings'),
    'access arguments' => array('administer site configuration'),
    'file' => 'phpids.admin.inc'
  );
  $items['phpidswarning'] = array(
    'title' => 'PHPIDS warning',
    'page callback' => 'phpids_warning',
    'access callback' => TRUE,
    'type' => MENU_CALLBACK
  );
  return $items;
}

/**
 * Implementation of hook_init().
 * $ignore : value depends which action will happen
 *   0 = do nothing
 *   1 = only log
 *   2 = log & actions
 */
function phpids_init() {

  if (file_exists(variable_get('phpids_path',realpath(dirname(__FILE__))). '/IDS/Config/Config.ini.php') || file_exists(variable_get('phpids_path',realpath(dirname(__FILE__))). '/IDS/Config/Config.ini')) {

    global $user, $base_root;

    // default is logging
    $ignore = 1;
    // anonymous user
    if ($user->uid == 0) {
      $anon = variable_get('phpids_anonymous',2);
      if ($anon == 2) $ignore = 2;
    }
    // authenticated user - always ignore user 1
    if ($user->uid != 0) {
      if ($user->uid == 1) $ignore = 0;
      else {
        $auth = variable_get('phpids_authenticated',2);
        if ($auth == 1) $ignore = 0;
        if ($auth == 3) $ignore = 2;        
      }
    }
        
    // start PHPIDS if ignore is not 0
    if ($ignore != 0) {
 
      $request_uri = $base_root . request_uri();

      // set include path and required the needed files
      $phpids_path = variable_get('phpids_path',realpath(dirname(__FILE__)));
      $phpids_tmppath = variable_get('phpids_tmppath',ini_get('upload_tmp_dir'). 'phpids');
      set_include_path(get_include_path(). PATH_SEPARATOR. $phpids_path);
      require_once 'IDS/Init.php';

      // instanciate the needed stuff
      $request = array_merge_recursive($_GET, $_POST, $_COOKIE);
	  if (file_exists(variable_get('phpids_path',realpath(dirname(__FILE__))). '/IDS/Config/Config.ini.php'))
        $init = IDS_Init::init($phpids_path.'/IDS/Config/Config.ini.php');
	  else
        $init = IDS_Init::init($phpids_path.'/IDS/Config/Config.ini');
      $init->config['General']['tmp_path'] = $phpids_tmppath;
      $init->config['General']['filter_path'] = $phpids_path . '/IDS/default_filter.xml';
      $init->config['General']['HTML_Purifier_Cache'] = $phpids_tmppath;
      $init->config['General']['html'] = explode(',', (variable_get('phpids_html_fields', '')));
      $init->config['General']['json'] = explode(',', (variable_get('phpids_json_fields', '')));
      $init->config['General']['exceptions'] = explode(',', (variable_get('phpids_excl_fields', '')));
      $init->config['Caching']['caching'] = 'file';
      $init->config['Caching']['path'] = $phpids_tmppath. '/default_filter.cache';

      $request = new IDS_Monitor($request, $init);
      $report = $request->run();

      // if report is not empty, always log
      // depending on variables, take other actions if impact level matches settings criteria.
      if (!$report->isEmpty()) {
        // default action is log
        $action = 0;

        // level of severity
        $severity = $report->getImpact(); 

        // get variables to see if we need to take more action than only logging
        $mail_level = variable_get('phpids_maillevel',9);
        $mail_sent = variable_get('phpids_mail','');
        $warn_level = variable_get('phpids_warnlevel',27);
        if ($severity >= $mail_level && !empty($mail_sent) && $ignore == 2) $action = 1;
        if ($severity >= $warn_level && $ignore == 2) $action = 2;

        // create detailed report
        $message = 'Total impact: ' . $severity . '<br />';
        $message .= 'All tags: ' . join(", ", $report->getTags()) . '<br />';
        // iterate through the result an get every event (IDS_Event)
        foreach ($report as $event) {
          $message .= '<hr>Variable: '.$event->getName().' | Value: ' . htmlspecialchars($event->getValue()) . '<br />';
          $message .= 'Impact: '.$event->getImpact().' | Tags: ' . join(", ", $event->getTags()) . '<br />'; 
          // iterator throught every filter 
          $message .= '<ul>';
          foreach ($event as $filter) {
            $message .= '<li>Rule: '. $filter->getRule() .'<br />';
            $message .= 'Description: '. $filter->getDescription() .'<br />';
            $message .= 'Tags: ' . join(", ", $filter->getTags()) . '</li>';
          }
          $message .= '</ul>';
        }

        // log the impact
        //phpids_addevent($user,$message,$severity,$action,$request_uri);
        watchdog('phpids',wordwrap($message,'100',' ',TRUE));

        // send out mail if needed
        if ($action >= 1 && $mail_sent != '') {
          drupal_mail('phpids','warning',$mail_sent,user_preferred_language($account),array('severity' => $severity));
          watchdog('phpids',wordwrap('Send warning mail to '.$mail_sent,'100',' ',TRUE));
        }
        // Warning : redirect the user to a warning page so nothing can happen to the system
        if ($action == 2) {
          // load common.inc and path.inc if necessary
          if (!function_exists('drupal_goto')) {
            require_once './includes/common.inc';
            require_once './includes/path.inc';
          }
          drupal_goto('phpidswarning');
        }
      }
    }
  }
}

/**
 * Mail function
 * @todo more info in mail  
 */
function phpids_mail($key,&$message,$params) {
  $language = $message['language'];
  $message['subject'] = t('Notification from !site', $variables, $language->language);
  $body = 'Check your logs to see a full detail of the report.';
  $message['subject'] = t('PHPIDS detected an attack with impact !severity', array('!severity' => $params['severity']));
  $message['body'] = t($body);
}

/**
 * Warning page: display this page if the attack has reached warning level thus
 * making the action of the (anonymous) user completely worthless.
 */
function phpids_warning() {
  $output = t('We have detected malicious input and blocked your attempt.<br />If you keep experiencing problems but feel like you are doing nothing wrong, please contact the site administrator.');
  return $output;
}