Club Drupal

<?php

/**

 * @file

 * Contains code for sanitizing user input from the request.

 */

/**

 * Sanitizes user input from the request.

 */

class DrupalRequestSanitizer {

  /**

   * Tracks whether the request was already sanitized.

   */

  protected static $sanitized = FALSE;

  /**

   * Modifies the request to strip dangerous keys from user input.

   */

  public static function sanitize() {

    if (!self::$sanitized) {

      $whitelist = variable_get('sanitize_input_whitelist', array());

      $log_sanitized_keys = variable_get('sanitize_input_logging', FALSE);

      // Process query string parameters.

      $get_sanitized_keys = array();

      $_GET = self::stripDangerousValues($_GET, $whitelist, $get_sanitized_keys);

      if ($log_sanitized_keys && $get_sanitized_keys) {

        _drupal_trigger_error_with_delayed_logging(format_string('Potentially unsafe keys removed from query string parameters (GET): @keys', array('@keys' => implode(', ', $get_sanitized_keys))), E_USER_NOTICE);

      }

      // Process request body parameters.

      $post_sanitized_keys = array();

      $_POST = self::stripDangerousValues($_POST, $whitelist, $post_sanitized_keys);

      if ($log_sanitized_keys && $post_sanitized_keys) {

        _drupal_trigger_error_with_delayed_logging(format_string('Potentially unsafe keys removed from request body parameters (POST): @keys', array('@keys' => implode(', ', $post_sanitized_keys))), E_USER_NOTICE);

      }

      // Process cookie parameters.

      $cookie_sanitized_keys = array();

      $_COOKIE = self::stripDangerousValues($_COOKIE, $whitelist, $cookie_sanitized_keys);

      if ($log_sanitized_keys && $cookie_sanitized_keys) {

        _drupal_trigger_error_with_delayed_logging(format_string('Potentially unsafe keys removed from cookie parameters (COOKIE): @keys', array('@keys' => implode(', ', $cookie_sanitized_keys))), E_USER_NOTICE);

      }

      $request_sanitized_keys = array();

      $_REQUEST = self::stripDangerousValues($_REQUEST, $whitelist, $request_sanitized_keys);

      self::$sanitized = TRUE;

    }

  }

  /**

   * Strips dangerous keys from the provided input.

   *

   * @param mixed $input

   *   The input to sanitize.

   * @param string[] $whitelist

   *   An array of keys to whitelist as safe.

   * @param string[] $sanitized_keys

   *   An array of keys that have been removed.

   *

   * @return mixed

   *   The sanitized input.

   */

  protected static function stripDangerousValues($input, array $whitelist, array &$sanitized_keys) {

    if (is_array($input)) {

      foreach ($input as $key => $value) {

        if ($key !== '' && $key[0] === '#' && !in_array($key, $whitelist, TRUE)) {

          unset($input[$key]);

          $sanitized_keys[] = $key;

        }

        else {

          $input[$key] = self::stripDangerousValues($input[$key], $whitelist, $sanitized_keys);

        }

      }

    }

    return $input;

  }

}