Backport CSRF prevention.

5 files changed, 115 insertions, 4 deletions

diff --git a/lib/json.php b/lib/json.php
index f3bbe9ac899..dfc0a7b894e 100644
--- a/lib/json.php
+++ b/lib/json.php
@@ -42,6 +42,18 @@ class OC_JSON{
 	}
 
 	/**
+	 * @brief Check an ajax get/post call if the request token is valid.
+	 * @return json Error msg if not valid.
+	 */
+	public static function callCheck(){
+		if( !OC_Util::isCallRegistered()){
+			$l = OC_L10N::get('core');
+			self::error(array( 'data' => array( 'message' => $l->t('Token expired. Please reload page.') )));
+			exit();
+		}
+	}
+        
+	/**
 	* Check if the user is a admin, send json error msg if not
 	*/
 	public static function checkAdminUser(){
diff --git a/lib/public/json.php b/lib/public/json.php
index 439721ac6ce..69a69925457 100644
--- a/lib/public/json.php
+++ b/lib/public/json.php
@@ -53,6 +53,13 @@ class JSON {
 		return(\OC_JSON::checkLoggedIn());
 	}
 
+	/**
+	 * @brief Check an ajax get/post call if the request token is valid.
+	 * @return json Error msg if not valid.
+	 */
+	public static function callCheck(){
+		return(\OC_JSON::callCheck());
+	}
 
 	/**
 	* @brief Send json success msg
diff --git a/lib/public/util.php b/lib/public/util.php
index 2abffba4c4a..bffe07da3f8 100644
--- a/lib/public/util.php
+++ b/lib/public/util.php
@@ -249,6 +249,22 @@ class Util {
 		return(\OC_Hook::emit( $signalclass, $signalname, $params ));
 	}
 
+	/**
+ 	 * Register an get/post call. This is important to prevent CSRF attacks
+	 * TODO: write example
+	 */
+	public static function callRegister(){
+		return(\OC_Util::callRegister());
+	}
+
+
+	/**
+	 * Check an ajax get/post call if the request token is valid. exit if not.
+	 * Todo: Write howto
+	 */
+	public static function callCheck(){
+		return(\OC_Util::callCheck());
+	}
 
 }
 
diff --git a/lib/template.php b/lib/template.php
index e908c76bfad..fd2cb34a4a9 100644
--- a/lib/template.php
+++ b/lib/template.php
@@ -155,11 +155,13 @@ class OC_Template{
 		$this->renderas = $renderas;
 		$this->application = $app;
 		$this->vars = array();
+		if($renderas == 'user') {
+			$this->vars['requesttoken'] = OC_Util::callRegister();
+		}
 		$this->l10n = OC_L10N::get($app);
-                header('X-Frame-Options: Sameorigin');
-                header('X-XSS-Protection: 1; mode=block');
-                header('X-Content-Type-Options: nosniff');
- 
+		header('X-Frame-Options: Sameorigin');
+		header('X-XSS-Protection: 1; mode=block');
+		header('X-Content-Type-Options: nosniff');
 		$this->findTemplate($name);
 	}
 
@@ -355,6 +357,7 @@ class OC_Template{
 			if( $this->renderas == "user" ){
 				$page = new OC_Template( "core", "layout.user" );
 				$page->assign('searchurl',OC_Helper::linkTo( 'search', 'index.php' ));
+				$page->assign('requesttoken', $this->vars['requesttoken']);
 				if(array_search(OC_APP::getCurrentApp(),array('settings','admin','help'))!==false){
 					$page->assign('bodyid','body-settings');
 				}else{
diff --git a/lib/util.php b/lib/util.php
index 49f658f3c0e..c47a7e5d84c 100644
--- a/lib/util.php
+++ b/lib/util.php
@@ -331,4 +331,77 @@ class OC_Util {
 		}
 		exit();
 	}
+
+	/**
+	 * @brief Register an get/post call. This is important to prevent CSRF attacks
+	 * Todo: Write howto
+	 * @return $token Generated token.
+	 */
+	public static function callRegister(){
+		//mamimum time before token exires
+		$maxtime=(60*60);  // 1 hour
+
+		// generate a random token.
+		$token=mt_rand(1000,9000).mt_rand(1000,9000).mt_rand(1000,9000);
+
+		// store the token together with a timestamp in the session.
+		$_SESSION['requesttoken-'.$token]=time();
+
+		// cleanup old tokens garbage collector
+		// only run every 20th time so we donīt waste cpu cycles
+		if(rand(0,20)==0) {  
+			foreach($_SESSION as $key=>$value) {
+				// search all tokens in the session
+				if(substr($key,0,12)=='requesttoken') {
+					if($value+$maxtime<time()){
+						// remove outdated tokens
+						unset($_SESSION[$key]);						
+					}
+				}	
+			}
+		}
+		// return the token
+		return($token);
+	}
+
+	/**
+	 * @brief Check an ajax get/post call if the request token is valid.
+	 * @return boolean False if request token is not set or is invalid.
+	 */
+	public static function isCallRegistered(){
+		//mamimum time before token exires
+		$maxtime=(60*60);  // 1 hour
+		if(isset($_GET['requesttoken'])) {
+			$token=$_GET['requesttoken'];
+		}elseif(isset($_POST['requesttoken'])){
+			$token=$_POST['requesttoken'];
+		}elseif(isset($_SERVER['HTTP_REQUESTTOKEN'])){
+			$token=$_SERVER['HTTP_REQUESTTOKEN'];
+		}else{
+			//no token found.
+			return false;
+		}
+		if(isset($_SESSION['requesttoken-'.$token])) {
+			$timestamp=$_SESSION['requesttoken-'.$token];
+			if($timestamp+$maxtime<time()){
+				return false;
+			}else{
+				//token valid
+				return true;
+			}
+		}else{
+			return false;
+		}
+	}
+
+	/**
+	 * @brief Check an ajax get/post call if the request token is valid. exit if not.
+	 * Todo: Write howto
+	 */
+	public static function callCheck(){
+		if(!OC_Util::isCallRegistered()) {
+			exit;
+		}
+	}
 }
+