<?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 = null;
/**
* Cache for $template_dir lookup
*
* @var array
*/
protected $_template_dir = null;
/**
* Cache for $config_dir lookup
*
* @var array
*/
protected $_config_dir = null;
/**
* Cache for $secure_dir lookup
*
* @var array
*/
protected $_secure_dir = null;
/**
* Cache for $php_resource_dir lookup
*
* @var array
*/
protected $_php_resource_dir = null;
/**
* Cache for $trusted_dir lookup
*
* @var array
*/
protected $_trusted_dir = null;
/**
* @param Smarty $smarty
*/
public function __construct($smarty) {
$this->smarty = $smarty;
}
/**
* 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", $compiler->lex->taglineno);
}
} elseif (in_array($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", $compiler->lex->taglineno);
}
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", $compiler->lex->taglineno);
}
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", $compiler->lex->taglineno);
}
} elseif (in_array($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", $compiler->lex->taglineno);
}
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 contant 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($this->trusted_constants)) {
if (!in_array($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 $filepath
*
* @return boolean true if directory is trusted
* @throws SmartyException if directory is not trusted
*/
public function isTrustedResourceDir($filepath) {
$_template = false;
$_config = false;
$_secure = false;
$_template_dir = $this->smarty->getTemplateDir();
$_config_dir = $this->smarty->getConfigDir();
// check if index is outdated
if ((!$this->_template_dir || $this->_template_dir !== $_template_dir)
|| (!$this->_config_dir || $this->_config_dir !== $_config_dir)
|| (!empty($this->secure_dir) && (!$this->_secure_dir || $this->_secure_dir !== $this->secure_dir))
) {
$this->_resource_dir = array();
$_template = true;
$_config = true;
$_secure = !empty($this->secure_dir);
}
// rebuild template dir index
if ($_template) {
$this->_template_dir = $_template_dir;
foreach ($_template_dir as $directory) {
$directory = realpath($directory);
$this->_resource_dir[$directory] = true;
}
}
// rebuild config dir index
if ($_config) {
$this->_config_dir = $_config_dir;
foreach ($_config_dir as $directory) {
$directory = realpath($directory);
$this->_resource_dir[$directory] = true;
}
}
// rebuild secure dir index
if ($_secure) {
$this->_secure_dir = $this->secure_dir;
foreach ((array)$this->secure_dir as $directory) {
$directory = realpath($directory);
$this->_resource_dir[$directory] = true;
}
}
$_filepath = realpath($filepath);
$directory = dirname($_filepath);
$_directory = array();
while (true) {
// remember the directory to add it to _resource_dir in case we're successful
$_directory[$directory] = true;
// test if the directory is trusted
if (isset($this->_resource_dir[$directory])) {
// merge sub directories of current $directory into _resource_dir to speed up subsequent lookup
$this->_resource_dir = array_merge($this->_resource_dir, $_directory);
return true;
}
// abort if we've reached root
if (($pos = strrpos($directory, DS)) === false || !isset($directory[1])) {
break;
}
// bubble up one level
$directory = substr($directory, 0, $pos);
}
// give up
throw new SmartyException("directory '{$_filepath}' not allowed by security setting");
}
/**
* 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) {
$directory = realpath($directory);
$this->_php_resource_dir[$directory] = true;
}
}
$_filepath = realpath($filepath);
$directory = dirname($_filepath);
$_directory = array();
while (true) {
// remember the directory to add it to _resource_dir in case we're successful
$_directory[] = $directory;
// test if the directory is trusted
if (isset($this->_php_resource_dir[$directory])) {
// merge sub directories of current $directory into _resource_dir to speed up subsequent lookup
$this->_php_resource_dir = array_merge($this->_php_resource_dir, $_directory);
return true;
}
// abort if we've reached root
if (($pos = strrpos($directory, DS)) === false || !isset($directory[2])) {
break;
}
// bubble up one level
$directory = substr($directory, 0, $pos);
}
throw new SmartyException("directory '{$_filepath}' not allowed by security setting");
}
/**
* 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
*
* @param $template
*/
public function exitTemplate($template) {
if ($this->max_template_nesting > 0) {
$this->_current_template_nesting--;
}
}
}