SecurityPolicy.php

<?php

/*
 * This file is part of Twig.
 *
 * (c) 2009 Fabien Potencier
 *
 * For the full copyright and license information, please view the LICENSE
 * file that was distributed with this source code.
 */

/**
 * Represents a security policy which need to be enforced when sandbox mode is enabled.
 *
 * @author Fabien Potencier <fabien@symfony.com>
 */
class Twig_Sandbox_SecurityPolicy implements Twig_Sandbox_SecurityPolicyInterface {
  protected $allowedTags;
  protected $allowedFilters;
  protected $allowedMethods;
  protected $allowedProperties;
  protected $allowedFunctions;
  public function __construct(array $allowedTags = array(), array $allowedFilters = array(), array $allowedMethods = array(), array $allowedProperties = array(), array $allowedFunctions = array()) {
    $this->allowedTags = $allowedTags;
    $this->allowedFilters = $allowedFilters;
    $this
      ->setAllowedMethods($allowedMethods);
    $this->allowedProperties = $allowedProperties;
    $this->allowedFunctions = $allowedFunctions;
  }
  public function setAllowedTags(array $tags) {
    $this->allowedTags = $tags;
  }
  public function setAllowedFilters(array $filters) {
    $this->allowedFilters = $filters;
  }
  public function setAllowedMethods(array $methods) {
    $this->allowedMethods = array();
    foreach ($methods as $class => $m) {
      $this->allowedMethods[$class] = array_map('strtolower', is_array($m) ? $m : array(
        $m,
      ));
    }
  }
  public function setAllowedProperties(array $properties) {
    $this->allowedProperties = $properties;
  }
  public function setAllowedFunctions(array $functions) {
    $this->allowedFunctions = $functions;
  }
  public function checkSecurity($tags, $filters, $functions) {
    foreach ($tags as $tag) {
      if (!in_array($tag, $this->allowedTags)) {
        throw new Twig_Sandbox_SecurityError(sprintf('Tag "%s" is not allowed.', $tag));
      }
    }
    foreach ($filters as $filter) {
      if (!in_array($filter, $this->allowedFilters)) {
        throw new Twig_Sandbox_SecurityError(sprintf('Filter "%s" is not allowed.', $filter));
      }
    }
    foreach ($functions as $function) {
      if (!in_array($function, $this->allowedFunctions)) {
        throw new Twig_Sandbox_SecurityError(sprintf('Function "%s" is not allowed.', $function));
      }
    }
  }
  public function checkMethodAllowed($obj, $method) {
    if ($obj instanceof Twig_TemplateInterface || $obj instanceof Twig_Markup) {
      return true;
    }
    $allowed = false;
    $method = strtolower($method);
    foreach ($this->allowedMethods as $class => $methods) {
      if ($obj instanceof $class) {
        $allowed = in_array($method, $methods);
        break;
      }
    }
    if (!$allowed) {
      throw new Twig_Sandbox_SecurityError(sprintf('Calling "%s" method on a "%s" object is not allowed.', $method, get_class($obj)));
    }
  }
  public function checkPropertyAllowed($obj, $property) {
    $allowed = false;
    foreach ($this->allowedProperties as $class => $properties) {
      if ($obj instanceof $class) {
        $allowed = in_array($property, is_array($properties) ? $properties : array(
          $properties,
        ));
        break;
      }
    }
    if (!$allowed) {
      throw new Twig_Sandbox_SecurityError(sprintf('Calling "%s" property on a "%s" object is not allowed.', $property, get_class($obj)));
    }
  }

}