Bounds check directories.

src/RageFileManager.cpp

@@ -350,6 +350,12 @@ void RageFileManager::GetDirListing( const RString &sPath_, vector<RString> &Add
 	RString sPath = sPath_;
 	NormalizePath( sPath );
 	
+	// NormalizePath() calls CollapsePath() which will remove "dir/.." pairs.
+	// So if a "/.." is still present, they're trying to go below the mountpoint,
+	// which isn't valid.
+	if( sPath.find("/..") != std::string::npos )
+		return;
+
 	vector<LoadedDriver *> apDriverList;
 	ReferenceAllDrivers( apDriverList );