bug #385 update to smarty-3.1.28-dev (from Github)

1 files changed, 408 insertions, 152 deletions

diff --git a/include/smarty/libs/sysplugins/smarty_security.php b/include/smarty/libs/sysplugins/smarty_security.php
index f8b31d963..9d48bcb21 100644
--- a/include/smarty/libs/sysplugins/smarty_security.php
+++ b/include/smarty/libs/sysplugins/smarty_security.php
@@ -2,25 +2,25 @@
 /**
  * Smarty plugin
  *
- * @package Smarty
+ * @package    Smarty
  * @subpackage Security
- * @author Uwe Tews
+ * @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? 
+ *        $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 {
-
+class Smarty_Security
+{
     /**
      * This determines how Smarty handles "<?php ... ?>" tags in templates.
      * possible values:
@@ -34,6 +34,7 @@ class Smarty_Security {
      * @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.
@@ -41,6 +42,7 @@ class Smarty_Security {
      * @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.
@@ -48,124 +50,208 @@ class Smarty_Security {
      * @var array
      */
     public $trusted_dir = array();
+
     /**
      * List of regular expressions (PCRE) that include trusted URIs
      *
      * @var array
      */
     public $trusted_uri = array();
+
     /**
-     * This is an array of trusted static classes.
+     * 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 array of trusted PHP functions.
+     * 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',
-        'nl2br',
-    );
+    public $php_functions = array('isset', 'empty', 'count', 'sizeof', 'in_array', 'is_array', 'time',);
+
     /**
-     * This is an array of trusted PHP modifers.
-     *
+     * This is an array of trusted PHP modifiers.
      * If empty all modifiers are allowed.
-     * To disable all modifier set $modifiers = null.
+     * To disable all modifier set $php_modifiers = null.
+     *
      * @var array
      */
-    public $php_modifiers = array(
-        'escape',
-        'count'
-    );
+    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 trusted streams.
+     * 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;
 
     /**
-     * Cache for $resource_dir lookups
+     * 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;
+    protected $_resource_dir = array();
+
     /**
-     * Cache for $template_dir lookups
+     * Cache for $template_dir lookup
+     *
      * @var array
      */
-    protected $_template_dir = null;
+    protected $_template_dir = array();
+
     /**
-     * Cache for $config_dir lookups
+     * Cache for $config_dir lookup
+     *
      * @var array
      */
-    protected $_config_dir = null;
+    protected $_config_dir = array();
+
     /**
-     * Cache for $secure_dir lookups
+     * Cache for $secure_dir lookup
+     *
      * @var array
      */
-    protected $_secure_dir = null;
+    protected $_secure_dir = array();
+
     /**
-     * Cache for $php_resource_dir lookups
+     * Cache for $php_resource_dir lookup
+     *
      * @var array
      */
     protected $_php_resource_dir = null;
+
     /**
-     * Cache for $trusted_dir lookups
+     * 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
      */
@@ -173,74 +259,129 @@ class Smarty_Security {
     {
         $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
+     * @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, $this->php_functions))) {
+        if (isset($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
+     * @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, $this->static_classes))) {
+        if (isset($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
+     * @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, $this->php_modifiers))) {
+        if (isset($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
+     * @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'))) {
+        if (in_array($tag_name, array('assign', 'call', 'private_filter', 'private_block_plugin',
+                                      'private_function_plugin', 'private_object_block_function',
+                                      'private_object_function', 'private_registered_function',
+                                      'private_registered_block', 'private_special_variable',
+                                      'private_print_expression', 'private_modifier'))) {
             return true;
         }
         // check security settings
@@ -248,22 +389,44 @@ class Smarty_Security {
             if (empty($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);
+                $compiler->trigger_template_error("tag '{$tag_name}' disabled by security setting", null, true);
             }
-        } else if (in_array($tag_name, $this->allowed_tags) && !in_array($tag_name, $this->disabled_tags)) {
+        } elseif (in_array($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 {
-            $compiler->trigger_template_error("tag '{$tag_name}' not allowed by security setting", $compiler->lex->taglineno);
+            $compiler->trigger_template_error("special variable '\$smarty.{$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
+     * @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, $compiler)
@@ -277,21 +440,52 @@ class Smarty_Security {
             if (empty($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);
+                $compiler->trigger_template_error("modifier '{$modifier_name}' disabled by security setting", null, true);
             }
-        } else if (in_array($modifier_name, $this->allowed_modifiers) && !in_array($modifier_name, $this->disabled_modifiers)) {
+        } elseif (in_array($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);
+            $compiler->trigger_template_error("modifier '{$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($this->trusted_constants)) {
+            if (!in_array($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
+     * @param  string $stream_name
+     *
+     * @return boolean         true if stream is trusted
      * @throws SmartyException if stream is not trusted
      */
     public function isTrustedStream($stream_name)
@@ -306,89 +500,81 @@ class Smarty_Security {
     /**
      * 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
+     * @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)
+    public function isTrustedResourceDir($filepath, $isConfig = null)
     {
-        $_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;
+        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 = $this->smarty->use_include_path;
         }
-
-        // rebuild config dir index
-        if ($_config) {
-            $this->_config_dir = $_config_dir;
-            foreach ($_config_dir as $directory) {
-                $directory = realpath($directory);
-                $this->_resource_dir[$directory] = true;
+        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;
             }
+            $this->smarty->_cache['template_dir_new'] = false;
         }
-
-        // rebuild secure dir index
-        if ($_secure) {
-            $this->_secure_dir = $this->secure_dir;
-            foreach ((array) $this->secure_dir as $directory) {
-                $directory = realpath($directory);
-                $this->_resource_dir[$directory] = true;
+        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;
         }
-
-        $_filepath = realpath($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 lookups
-                $this->_resource_dir = array_merge($this->_resource_dir, $_directory);
-                return true;
+        if ($this->_secure_dir !== (array) $this->secure_dir) {
+            foreach ($this->_secure_dir as $directory) {
+                unset($this->_resource_dir[$directory]);
             }
-            // abort if we've reached root
-            if (($pos = strrpos($directory, DS)) === false || !isset($directory[1])) {
-                break;
+            foreach ((array) $this->secure_dir as $directory) {
+                $directory = $this->smarty->_realpath($directory . DS, true);
+                $this->_resource_dir[$directory] = true;
             }
-            // bubble up one level
-            $directory = substr($directory, 0, $pos);
+            $this->_secure_dir = (array) $this->secure_dir;
         }
-
-        // give up
-        throw new SmartyException("directory '{$_filepath}' not allowed by security setting");
+        $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
+     *
+     * @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 $uri
      */
@@ -403,15 +589,16 @@ class Smarty_Security {
                 }
             }
         }
-        
+
         throw new SmartyException("URI '{$uri}' not allowed by security setting");
     }
-    
+
     /**
      * Check if directory of file resource is trusted.
      *
-     * @param string $filepath
-     * @return boolean true if directory is trusted
+     * @param  string $filepath
+     *
+     * @return boolean         true if directory is trusted
      * @throws SmartyException if PHP directory is not trusted
      */
     public function isTrustedPHPDir($filepath)
@@ -426,34 +613,103 @@ class Smarty_Security {
 
             $this->_trusted_dir = $this->trusted_dir;
             foreach ((array) $this->trusted_dir as $directory) {
-                $directory = realpath($directory);
+                $directory = $this->smarty->_realpath($directory . DS, true);
                 $this->_php_resource_dir[$directory] = true;
             }
         }
 
-        $_filepath = realpath($filepath);
-        $directory = dirname($_filepath);
+        $this->_php_resource_dir = $this->_checkDir($this->smarty->_realpath($filepath, true), $this->_php_resource_dir);
+        return true;
+    }
+
+    /**
+     * 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
+     *
+     * @internal param $template
+     */
+    public function exitTemplate()
+    {
+        if ($this->max_template_nesting > 0) {
+            $this->_current_template_nesting --;
+        }
+    }
+
+    /**
+     * 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) . DS;
         $_directory = array();
         while (true) {
             // remember the directory to add it to _resource_dir in case we're successful
-            $_directory[] = $directory;
+            $_directory[$directory] = true;
             // 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 lookups
-                $this->_php_resource_dir = array_merge($this->_php_resource_dir, $_directory);
-                return true;
+            if (isset($dirs[$directory])) {
+                // merge sub directories of current $directory into _resource_dir to speed up subsequent lookup
+                $dirs = array_merge($dirs, $_directory);
+
+                return $dirs;
             }
             // abort if we've reached root
-            if (($pos = strrpos($directory, DS)) === false || !isset($directory[2])) {
+            if (!preg_match('#[\\\/][^\\\/]+[\\\/]$#', $directory)) {
                 break;
             }
             // bubble up one level
-            $directory = substr($directory, 0, $pos);
+            $directory = preg_replace('#[\\\/][^\\\/]+[\\\/]$#', DS, $directory);
         }
 
-        throw new SmartyException("directory '{$_filepath}' not allowed by security setting");
+        // give up
+        throw new SmartyException("directory '{$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;
+    }
 }
-
-?>
\ No newline at end of file