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|
<?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 !== $this->smarty->use_include_path) {
foreach ($this->_include_dir as $directory) {
unset($this->_resource_dir[ $directory ]);
}
if ($this->smarty->use_include_path) {
$this->_include_dir = array();
$_dirs = $this->smarty->ext->_getIncludePath->getIncludePathDirs($this->smarty);
foreach ($_dirs as $directory) {
$this->_include_dir[] = $directory;
$this->_resource_dir[ $directory ] = true;
}
}
$this->_include_path_status = $this->smarty->use_include_path;
}
if ($isConfig !== true &&
(!isset($this->smarty->_cache[ 'template_dir_new' ]) || $this->smarty->_cache[ 'template_dir_new' ])
) {
$_dir = $this->smarty->getTemplateDir();
if ($this->_template_dir !== $_dir) {
foreach ($this->_template_dir as $directory) {
unset($this->_resource_dir[ $directory ]);
}
foreach ($_dir as $directory) {
$this->_resource_dir[ $directory ] = true;
}
$this->_template_dir = $_dir;
}
$this->smarty->_cache[ 'template_dir_new' ] = false;
}
if ($isConfig !== false &&
(!isset($this->smarty->_cache[ 'config_dir_new' ]) || $this->smarty->_cache[ 'config_dir_new' ])
) {
$_dir = $this->smarty->getConfigDir();
if ($this->_config_dir !== $_dir) {
foreach ($this->_config_dir as $directory) {
unset($this->_resource_dir[ $directory ]);
}
foreach ($_dir as $directory) {
$this->_resource_dir[ $directory ] = true;
}
$this->_config_dir = $_dir;
}
$this->smarty->_cache[ 'config_dir_new' ] = false;
}
if ($this->_secure_dir !== (array) $this->secure_dir) {
foreach ($this->_secure_dir as $directory) {
unset($this->_resource_dir[ $directory ]);
}
foreach ((array) $this->secure_dir as $directory) {
$directory = $this->smarty->_realpath($directory . DIRECTORY_SEPARATOR, true);
$this->_resource_dir[ $directory ] = true;
}
$this->_secure_dir = (array) $this->secure_dir;
}
$this->_resource_dir = $this->_checkDir($filepath, $this->_resource_dir);
return true;
}
/**
* Check if URI (e.g. {fetch} or {html_image}) is trusted
* To simplify things, isTrustedUri() resolves all input to "{$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;
}
}
$this->_php_resource_dir =
$this->_checkDir($this->smarty->_realpath($filepath, true), $this->_php_resource_dir);
return true;
}
/**
* Check if file is inside a valid directory
*
* @param string $filepath
* @param array $dirs valid directories
*
* @return array
* @throws \SmartyException
*/
private function _checkDir($filepath, $dirs)
{
$directory = dirname($filepath) . DIRECTORY_SEPARATOR;
$_directory = array();
while (true) {
// remember the directory to add it to _resource_dir in case we're successful
$_directory[ $directory ] = true;
// test if the directory is trusted
if (isset($dirs[ $directory ])) {
// merge sub directories of current $directory into _resource_dir to speed up subsequent lookup
$dirs = array_merge($dirs, $_directory);
return $dirs;
}
// abort if we've reached root
if (!preg_match('#[\\\/][^\\\/]+[\\\/]$#', $directory)) {
break;
}
// 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 = $security_class;
return;
} elseif (is_object($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;
}
/**
* 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');
}
}
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