Synthesizing Mutable Configurations: Setting up Systems for Success

Abstract

Numerous devices, from network switches and servers to industrial control systems, can be unreliable if they are not configured properly. Even if a device's implementation has been proven correct, it must still be configured to meet the specific functional and security requirements of its stakeholders. However, manual configuration remains labor intensive and error-prone even for experts. Automated configuration synthesis presents a promising way forward. Unfortunately, as we show, existing counterexample-guided algorithms can perform poorly if the system model allows configuration changes during execution. Yet disallowing such changes can hide significant problems, such as privilege escalation. We present a new synthesis algorithm that exploits structure inherent in state-machine models where the system configuration changes. We implement it using the Kodkod relational model finder, and show that it favorably solves a number of configuration-synthesis tasks.