Dynamically reconfigurable trust policies for untrustworthy third-party components

Dynamic component-based platforms allow software to evolve at runtime, that is, components that can be located, loaded, and executed during runtime. Such dynamic update mechanism provides flexibility but introduces new challenges. This is especially true when dealing with third-party components, which make hard to predict the impacts (e.g., component incompatibilities at runtime, errors leading to application crashes) when integrating such thirdparty code into an application. Component quality is something hard to be evaluated and even harder when components are combined together. Third-party components whose origin or quality attributes are unknown may be considered as untrustworthy since they may potentially introduce faults to applications, although unintentionally. This paper describes the dynamic policy (i.e. changeable at runtime) behind our solution for temporarily isolating components in a sandbox, avoiding the trusted components to be disturbed in case the third-party code behaves inappropriately. By providing such mechanism we help introducing dependability attributes (namely maintainability, reliability and availability) in the component platform's architecture. In case the component presents no harm to the system, our approach provides the ability to promote a component outside the sandbox.