[ticket/15692] Check if argument is a valid resource

PHPBB3-15692

phpBB/language/en/common.php

@@ -745,6 +745,7 @@ $lang = array_merge($lang, array(
 	'STORAGE_CANNOT_CREATE_DIR'		=> 'Can not create directory.',
 	'STORAGE_CANNOT_OPEN_FILE'		=> 'Can not open file.',
 	'STORAGE_CANNOT_CREATE_FILE'	=> 'Can not create file.',
+	'STORAGE_INVALID_RESOURCE'		=> 'Resource is invalid.',
 
 	'TB'				=> 'TB',
 	'TERMS_LINK'		=> 'Terms',

phpBB/phpbb/storage/storage.php

@@ -271,6 +271,11 @@ class storage
 			throw new exception('STORAGE_FILE_EXISTS', $path);
 		}
 
+		if (!is_resource($resource))
+		{
+			throw new exception('STORAGE_INVALID_RESOURCE');
+		}
+
 		$adapter = $this->get_adapter();
 
 		if ($adapter instanceof stream_interface)