Merge pull request #1689 from EXreaction/ticket/11727

[ticket/11727] Mark style directories safe to load from

phpBB/phpbb/template/twig/loader.php

@@ -0,0 +1,150 @@
+<?php
+/**
+*
+* @package phpBB3
+* @copyright (c) 2013 phpBB Group
+* @license http://opensource.org/licenses/gpl-2.0.php GNU General Public License v2
+*
+*/
+
+/**
+* @ignore
+*/
+if (!defined('IN_PHPBB'))
+{
+	exit;
+}
+
+/**
+* Twig Template loader
+* @package phpBB3
+*/
+class phpbb_template_twig_loader extends Twig_Loader_Filesystem
+{
+	protected $safe_directories = array();
+
+	/**
+	* Set safe directories
+	*
+	* @param array $directories Array of directories that are safe (empty to clear)
+	* @return Twig_Loader_Filesystem
+	*/
+	public function setSafeDirectories($directories = array())
+	{
+		$this->safe_directories = array();
+
+		if (!empty($directories))
+		{
+			foreach ($directories as $directory)
+			{
+				$this->addSafeDirectory($directory);
+			}
+		}
+
+		return $this;
+	}
+
+	/**
+	* Add safe directory
+	*
+	* @param string $directory Directory that should be added
+	* @return Twig_Loader_Filesystem
+	*/
+	public function addSafeDirectory($directory)
+	{
+		$directory = phpbb_realpath($directory);
+
+		if ($directory !== false)
+		{
+			$this->safe_directories[] = $directory;
+		}
+
+		return $this;
+	}
+
+	/**
+	* Get current safe directories
+	*
+	* @return array
+	*/
+	public function getSafeDirectories()
+	{
+		return $this->safe_directories;
+	}
+
+	/**
+	* Override for parent::validateName()
+	*
+	* This is done because we added support for safe directories, and when Twig
+	*	findTemplate() is called, validateName() is called first, which would
+	*	always throw an exception if the file is outside of the configured
+	*	template directories.
+	*/
+	protected function validateName($name)
+	{
+		return;
+	}
+
+	/**
+	* Find the template
+	*
+	* Override for Twig_Loader_Filesystem::findTemplate to add support
+	*	for loading from safe directories.
+	*/
+	protected function findTemplate($name)
+	{
+		$name = (string) $name;
+
+		// normalize name
+		$name = preg_replace('#/{2,}#', '/', strtr($name, '\\', '/'));
+
+		// If this is in the cache we can skip the entire process below
+		//	as it should have already been validated
+		if (isset($this->cache[$name])) {
+			return $this->cache[$name];
+		}
+
+		// First, find the template name. The override above of validateName
+		//	causes the validateName process to be skipped for this call
+		$file = parent::findTemplate($name);
+
+		try
+		{
+			// Try validating the name (which may throw an exception)
+			parent::validateName($name);
+		}
+		catch (Twig_Error_Loader $e)
+		{
+			if (strpos($e->getRawMessage(), 'Looks like you try to load a template outside configured directories') === 0)
+			{
+				// Ok, so outside of the configured template directories, we
+				//	can now check if we're within a "safe" directory
+
+				// Find the real path of the directory the file is in
+				$directory = phpbb_realpath(dirname($file));
+
+				if ($directory === false)
+				{
+					// Some sort of error finding the actual path, must throw the exception
+					throw $e;
+				}
+
+				foreach ($this->safe_directories as $safe_directory)
+				{
+					if (strpos($directory, $safe_directory) === 0)
+					{
+						// The directory being loaded is below a directory
+						// that is "safe". We're good to load it!
+						return $file;
+					}
+				}
+			}
+
+			// Not within any safe directories
+			throw $e;
+		}
+
+		// No exception from validateName, safe to load.
+		return $file;
+	}
+}

phpBB/phpbb/template/twig/twig.php

@@ -91,7 +91,7 @@ class phpbb_template_twig extends phpbb_template_base
 		$this->cachepath = $phpbb_root_path . 'cache/twig/';
 
 		// Initiate the loader, __main__ namespace paths will be setup later in set_style_names()
-		$loader = new Twig_Loader_Filesystem('');
+		$loader = new phpbb_template_twig_loader('');
 
 		$this->twig = new phpbb_template_twig_environment(
 			$this->config,
@@ -181,11 +181,15 @@ class phpbb_template_twig extends phpbb_template_base
 		{
 			foreach ($names as $name)
 			{
-				$path = $this->phpbb_root_path . trim($directory, '/') . "/{$name}/template/";
+				$path = $this->phpbb_root_path . trim($directory, '/') . "/{$name}/";
+				$template_path = $path . 'template/';
 
-				if (is_dir($path))
+				if (is_dir($template_path))
 				{
-					$paths[] = $path;
+					// Add the base style directory as a safe directory
+					$this->twig->getLoader()->addSafeDirectory($path);
+
+					$paths[] = $template_path;
 				}
 			}
 		}
@@ -233,11 +237,15 @@ class phpbb_template_twig extends phpbb_template_base
 
 				foreach ($names as $style_name)
 				{
-					$ext_style_path = $ext_path . 'styles/' . $style_name . '/template';
+					$ext_style_path = $ext_path . 'styles/' . $style_name . '/';
+					$ext_style_template_path = $ext_style_path . 'template/';
 
-					if (is_dir($ext_style_path))
+					if (is_dir($ext_style_template_path))
 					{
-						$paths[] = $ext_style_path;
+						// Add the base style directory as a safe directory
+						$this->twig->getLoader()->addSafeDirectory($ext_style_path);
+
+						$paths[] = $ext_style_template_path;
 					}
 				}