<?php /** * Smarty plugin * * @package Smarty * @subpackage Security * @author Uwe Tews */ /* * FIXME: Smarty_Security API * - getter and setter instead of public properties would allow cultivating an internal cache properly * - current implementation of isTrustedResourceDir() assumes that Smarty::$template_dir and Smarty::$config_dir are immutable * the cache is killed every time either of the variables change. That means that two distinct Smarty objects with differing * $template_dir or $config_dir should NOT share the same Smarty_Security instance, * as this would lead to (severe) performance penalty! how should this be handled? */ /** * This class does contain the security settings */ class Smarty_Security { /** * This determines how Smarty handles "<?php ... ?>" tags in templates. * possible values: * <ul> * <li>Smarty::PHP_PASSTHRU -> echo PHP tags as they are</li> * <li>Smarty::PHP_QUOTE -> escape tags as entities</li> * <li>Smarty::PHP_REMOVE -> remove php tags</li> * <li>Smarty::PHP_ALLOW -> execute php tags</li> * </ul> * * @var integer */ public $php_handling = Smarty::PHP_PASSTHRU; /** * This is the list of template directories that are considered secure. * $template_dir is in this list implicitly. * * @var array */ public $secure_dir = array(); /** * This is an array of directories where trusted php scripts reside. * {@link $security} is disabled during their inclusion/execution. * * @var array */ public $trusted_dir = array(); /** * List of regular expressions (PCRE) that include trusted URIs * * @var array */ public $trusted_uri = array(); /** * List of trusted constants names * * @var array */ public $trusted_constants = array(); /** * This is an array of trusted static classes. * If empty access to all static classes is allowed. * If set to 'none' none is allowed. * * @var array */ public $static_classes = array(); /** * This is an nested array of trusted classes and static methods. * If empty access to all static classes and methods is allowed. * Format: * array ( * 'class_1' => array('method_1', 'method_2'), // allowed methods listed * 'class_2' => array(), // all methods of class allowed * ) * If set to null none is allowed. * * @var array */ public $trusted_static_methods = array(); /** * This is an array of trusted static properties. * If empty access to all static classes and properties is allowed. * Format: * array ( * 'class_1' => array('prop_1', 'prop_2'), // allowed properties listed * 'class_2' => array(), // all properties of class allowed * ) * If set to null none is allowed. * * @var array */ public $trusted_static_properties = array(); /** * This is an array of trusted PHP functions. * If empty all functions are allowed. * To disable all PHP functions set $php_functions = null. * * @var array */ public $php_functions = array('isset', 'empty', 'count', 'sizeof', 'in_array', 'is_array', 'time',); /** * This is an array of trusted PHP modifiers. * If empty all modifiers are allowed. * To disable all modifier set $php_modifiers = null. * * @var array */ public $php_modifiers = array('escape', 'count', 'nl2br',); /** * This is an array of allowed tags. * If empty no restriction by allowed_tags. * * @var array */ public $allowed_tags = array(); /** * This is an array of disabled tags. * If empty no restriction by disabled_tags. * * @var array */ public $disabled_tags = array(); /** * This is an array of allowed modifier plugins. * If empty no restriction by allowed_modifiers. * * @var array */ public $allowed_modifiers = array(); /** * This is an array of disabled modifier plugins. * If empty no restriction by disabled_modifiers. * * @var array */ public $disabled_modifiers = array(); /** * This is an array of disabled special $smarty variables. * * @var array */ public $disabled_special_smarty_vars = array(); /** * This is an array of trusted streams. * If empty all streams are allowed. * To disable all streams set $streams = null. * * @var array */ public $streams = array('file'); /** * + flag if constants can be accessed from template * * @var boolean */ public $allow_constants = true; /** * + flag if super globals can be accessed from template * * @var boolean */ public $allow_super_globals = true; /** * max template nesting level * * @var int */ public $max_template_nesting = 0; /** * current template nesting level * * @var int */ private $_current_template_nesting = 0; /** * Cache for $resource_dir lookup * * @var array */ protected $_resource_dir = array(); /** * Cache for $template_dir lookup * * @var array */ protected $_template_dir = array(); /** * Cache for $config_dir lookup * * @var array */ protected $_config_dir = array(); /** * Cache for $secure_dir lookup * * @var array */ protected $_secure_dir = array(); /** * Cache for $php_resource_dir lookup * * @var array */ protected $_php_resource_dir = null; /** * Cache for $trusted_dir lookup * * @var array */ protected $_trusted_dir = null; /** * Cache for include path status * * @var bool */ protected $_include_path_status = false; /** * Cache for $_include_array lookup * * @var array */ protected $_include_dir = array(); /** * @param Smarty $smarty */ public function __construct($smarty) { $this->smarty = $smarty; $this->smarty->_cache[ 'template_dir_new' ] = true; $this->smarty->_cache[ 'config_dir_new' ] = true; } /** * Check if PHP function is trusted. * * @param string $function_name * @param object $compiler compiler object * * @return boolean true if function is trusted * @throws SmartyCompilerException if php function is not trusted */ public function isTrustedPhpFunction($function_name, $compiler) { if (isset($this->php_functions) && (empty($this->php_functions) || in_array($function_name, $this->php_functions)) ) { return true; } $compiler->trigger_template_error("PHP function '{$function_name}' not allowed by security setting"); return false; // should not, but who knows what happens to the compiler in the future? } /** * Check if static class is trusted. * * @param string $class_name * @param object $compiler compiler object * * @return boolean true if class is trusted * @throws SmartyCompilerException if static class is not trusted */ public function isTrustedStaticClass($class_name, $compiler) { if (isset($this->static_classes) && (empty($this->static_classes) || in_array($class_name, $this->static_classes)) ) { return true; } $compiler->trigger_template_error("access to static class '{$class_name}' not allowed by security setting"); return false; // should not, but who knows what happens to the compiler in the future? } /** * Check if static class method/property is trusted. * * @param string $class_name * @param string $params * @param object $compiler compiler object * * @return boolean true if class method is trusted * @throws SmartyCompilerException if static class method is not trusted */ public function isTrustedStaticClassAccess($class_name, $params, $compiler) { if (!isset($params[ 2 ])) { // fall back return $this->isTrustedStaticClass($class_name, $compiler); } if ($params[ 2 ] === 'method') { $allowed = $this->trusted_static_methods; $name = substr($params[ 0 ], 0, strpos($params[ 0 ], '(')); } else { $allowed = $this->trusted_static_properties; // strip '$' $name = substr($params[ 0 ], 1); } if (isset($allowed)) { if (empty($allowed)) { // fall back return $this->isTrustedStaticClass($class_name, $compiler); } if (isset($allowed[ $class_name ]) && (empty($allowed[ $class_name ]) || in_array($name, $allowed[ $class_name ])) ) { return true; } } $compiler->trigger_template_error("access to static class '{$class_name}' {$params[2]} '{$name}' not allowed by security setting"); return false; // should not, but who knows what happens to the compiler in the future? } /** * Check if PHP modifier is trusted. * * @param string $modifier_name * @param object $compiler compiler object * * @return boolean true if modifier is trusted * @throws SmartyCompilerException if modifier is not trusted */ public function isTrustedPhpModifier($modifier_name, $compiler) { if (isset($this->php_modifiers) && (empty($this->php_modifiers) || in_array($modifier_name, $this->php_modifiers)) ) { return true; } $compiler->trigger_template_error("modifier '{$modifier_name}' not allowed by security setting"); return false; // should not, but who knows what happens to the compiler in the future? } /** * Check if tag is trusted. * * @param string $tag_name * @param object $compiler compiler object * * @return boolean true if tag is trusted * @throws SmartyCompilerException if modifier is not trusted */ public function isTrustedTag($tag_name, $compiler) { // check for internal always required tags if (in_array($tag_name, array('assign', 'call', 'private_filter', 'private_block_plugin', 'private_function_plugin', 'private_object_block_function', 'private_object_function', 'private_registered_function', 'private_registered_block', 'private_special_variable', 'private_print_expression', 'private_modifier'))) { return true; } // check security settings if (empty($this->allowed_tags)) { if (empty($this->disabled_tags) || !in_array($tag_name, $this->disabled_tags)) { return true; } else { $compiler->trigger_template_error("tag '{$tag_name}' disabled by security setting", null, true); } } elseif (in_array($tag_name, $this->allowed_tags) && !in_array($tag_name, $this->disabled_tags)) { return true; } else { $compiler->trigger_template_error("tag '{$tag_name}' not allowed by security setting", null, true); } return false; // should not, but who knows what happens to the compiler in the future? } /** * Check if special $smarty variable is trusted. * * @param string $var_name * @param object $compiler compiler object * * @return boolean true if tag is trusted * @throws SmartyCompilerException if modifier is not trusted */ public function isTrustedSpecialSmartyVar($var_name, $compiler) { if (!in_array($var_name, $this->disabled_special_smarty_vars)) { return true; } else { $compiler->trigger_template_error("special variable '\$smarty.{$var_name}' not allowed by security setting", null, true); } return false; // should not, but who knows what happens to the compiler in the future? } /** * Check if modifier plugin is trusted. * * @param string $modifier_name * @param object $compiler compiler object * * @return boolean true if tag is trusted * @throws SmartyCompilerException if modifier is not trusted */ public function isTrustedModifier($modifier_name, $compiler) { // check for internal always allowed modifier if (in_array($modifier_name, array('default'))) { return true; } // check security settings if (empty($this->allowed_modifiers)) { if (empty($this->disabled_modifiers) || !in_array($modifier_name, $this->disabled_modifiers)) { return true; } else { $compiler->trigger_template_error("modifier '{$modifier_name}' disabled by security setting", null, true); } } elseif (in_array($modifier_name, $this->allowed_modifiers) && !in_array($modifier_name, $this->disabled_modifiers) ) { return true; } else { $compiler->trigger_template_error("modifier '{$modifier_name}' not allowed by security setting", null, true); } return false; // should not, but who knows what happens to the compiler in the future? } /** * Check if constants are enabled or trusted * * @param string $const constant name * @param object $compiler compiler object * * @return bool */ public function isTrustedConstant($const, $compiler) { if (in_array($const, array('true', 'false', 'null'))) { return true; } if (!empty($this->trusted_constants)) { if (!in_array(strtolower($const), $this->trusted_constants)) { $compiler->trigger_template_error("Security: access to constant '{$const}' not permitted"); return false; } return true; } if ($this->allow_constants) { return true; } $compiler->trigger_template_error("Security: access to constants not permitted"); return false; } /** * Check if stream is trusted. * * @param string $stream_name * * @return boolean true if stream is trusted * @throws SmartyException if stream is not trusted */ public function isTrustedStream($stream_name) { if (isset($this->streams) && (empty($this->streams) || in_array($stream_name, $this->streams))) { return true; } throw new SmartyException("stream '{$stream_name}' not allowed by security setting"); } /** * Check if directory of file resource is trusted. * * @param string $filepath * @param null|bool $isConfig * * @return bool true if directory is trusted * @throws \SmartyException if directory is not trusted */ public function isTrustedResourceDir($filepath, $isConfig = null) { if ($this->_include_path_status !== $this->smarty->use_include_path) { $_dir = $this->smarty->use_include_path ? $this->smarty->ext->_getIncludePath->getIncludePathDirs($this->smarty) : array(); if ($this->_include_dir !== $_dir) { $this->_updateResourceDir($this->_include_dir, $_dir); $this->_include_dir = $_dir; } $this->_include_path_status = $this->smarty->use_include_path; } if ($isConfig !== true) { $_dir = $this->smarty->getTemplateDir(); if ($this->_template_dir !== $_dir) { $this->_updateResourceDir($this->_template_dir, $_dir); $this->_template_dir = $_dir; } } if ($isConfig !== false) { $_dir = $this->smarty->getConfigDir(); if ($this->_config_dir !== $_dir) { $this->_updateResourceDir($this->_config_dir, $_dir); $this->_config_dir = $_dir; } } if ($this->_secure_dir !== $this->secure_dir) { $this->secure_dir = (array)$this->secure_dir; foreach($this->secure_dir as $k => $d) { $this->secure_dir[$k] = $this->smarty->_realpath($d.DIRECTORY_SEPARATOR,true); } $this->_updateResourceDir($this->_secure_dir, $this->secure_dir); $this->_secure_dir = $this->secure_dir; } $addPath = $this->_checkDir($filepath, $this->_resource_dir); if ($addPath !== false) { $this->_resource_dir = array_merge($this->_resource_dir, $addPath); } return true; } /** * Check if URI (e.g. {fetch} or {html_image}) is trusted * To simplify things, isTrustedUri() resolves all input to "{$PROTOCOL}://{$HOSTNAME}". * So "http://username:password@hello.world.example.org:8080/some-path?some=query-string" * is reduced to "http://hello.world.example.org" prior to applying the patters from {@link $trusted_uri}. * * @param string $uri * * @return boolean true if URI is trusted * @throws SmartyException if URI is not trusted * @uses $trusted_uri for list of patterns to match against $uri */ public function isTrustedUri($uri) { $_uri = parse_url($uri); if (!empty($_uri[ 'scheme' ]) && !empty($_uri[ 'host' ])) { $_uri = $_uri[ 'scheme' ] . '://' . $_uri[ 'host' ]; foreach ($this->trusted_uri as $pattern) { if (preg_match($pattern, $_uri)) { return true; } } } throw new SmartyException("URI '{$uri}' not allowed by security setting"); } /** * Check if directory of file resource is trusted. * * @param string $filepath * * @return boolean true if directory is trusted * @throws SmartyException if PHP directory is not trusted */ public function isTrustedPHPDir($filepath) { if (empty($this->trusted_dir)) { throw new SmartyException("directory '{$filepath}' not allowed by security setting (no trusted_dir specified)"); } // check if index is outdated if (!$this->_trusted_dir || $this->_trusted_dir !== $this->trusted_dir) { $this->_php_resource_dir = array(); $this->_trusted_dir = $this->trusted_dir; foreach ((array) $this->trusted_dir as $directory) { $directory = $this->smarty->_realpath($directory . DIRECTORY_SEPARATOR, true); $this->_php_resource_dir[ $directory ] = true; } } $addPath = $this->_checkDir($filepath, $this->_php_resource_dir); if ($addPath !== false) { $this->_php_resource_dir = array_merge($this->_php_resource_dir, $addPath); } return true; } /** * Remove old directories and its sub folders, add new directories * * @param array $oldDir * @param array $newDir */ private function _updateResourceDir($oldDir, $newDir) { foreach ($oldDir as $directory) { $directory = $this->smarty->_realpath($directory, true); $length = strlen($directory); foreach ($this->_resource_dir as $dir) { if (substr($dir, 0,$length) === $directory) { unset($this->_resource_dir[ $dir ]); } } } foreach ($newDir as $directory) { $directory = $this->smarty->_realpath($directory, true); $this->_resource_dir[ $directory ] = true; } } /** * Check if file is inside a valid directory * * @param string $filepath * @param array $dirs valid directories * * @return array|bool * @throws \SmartyException */ private function _checkDir($filepath, $dirs) { $directory = dirname($filepath) . DIRECTORY_SEPARATOR; if (isset($dirs[ $directory ])) { return false; } $filepath = $this->smarty->_realpath($filepath, true); $directory = dirname($filepath) . DIRECTORY_SEPARATOR; $_directory = array(); while (true) { // test if the directory is trusted if (isset($dirs[ $directory ])) { return $_directory; } // abort if we've reached root if (!preg_match('#[\\\/][^\\\/]+[\\\/]$#', $directory)) { break; } // remember the directory to add it to _resource_dir in case we're successful $_directory[ $directory ] = true; // bubble up one level $directory = preg_replace('#[\\\/][^\\\/]+[\\\/]$#', DIRECTORY_SEPARATOR, $directory); } // give up throw new SmartyException("directory '{$filepath}' not allowed by security setting"); } /** * Loads security class and enables security * * @param \Smarty $smarty * @param string|Smarty_Security $security_class if a string is used, it must be class-name * * @return \Smarty current Smarty instance for chaining * @throws \SmartyException when an invalid class name is provided */ public static function enableSecurity(Smarty $smarty, $security_class) { if ($security_class instanceof Smarty_Security) { $smarty->security_policy = $security_class; return $smarty; } elseif (is_object($security_class)) { throw new SmartyException("Class '" . get_class($security_class) . "' must extend Smarty_Security."); } if ($security_class === null) { $security_class = $smarty->security_class; } if (!class_exists($security_class)) { throw new SmartyException("Security class '$security_class' is not defined"); } elseif ($security_class !== 'Smarty_Security' && !is_subclass_of($security_class, 'Smarty_Security')) { throw new SmartyException("Class '$security_class' must extend Smarty_Security."); } else { $smarty->security_policy = new $security_class($smarty); } return $smarty; } /** * Start template processing * * @param $template * * @throws SmartyException */ public function startTemplate($template) { if ($this->max_template_nesting > 0 && $this->_current_template_nesting ++ >= $this->max_template_nesting) { throw new SmartyException("maximum template nesting level of '{$this->max_template_nesting}' exceeded when calling '{$template->template_resource}'"); } } /** * Exit template processing * */ public function endTemplate() { if ($this->max_template_nesting > 0) { $this->_current_template_nesting --; } } /** * Register callback functions call at start/end of template rendering * * @param \Smarty_Internal_Template $template */ public function registerCallBacks(Smarty_Internal_Template $template) { $template->startRenderCallbacks[] = array($this, 'startTemplate'); $template->endRenderCallbacks[] = array($this, 'endTemplate'); } }