Paul Gazzillo

Arthur Amorim, Paul Gazzillo, Max Taylor et al.

Standard communication protocols for Unmanned Aerial Vehicles (UAVs), such as MAVLink, lack the capability to enforce the contextual validity of message sequences. Autopilots therefore remain vulnerable to stealthy attacks, where syntactically correct but semantically ill-timed commands induce unsafe states without triggering physical anomaly detectors. Prior work (DATUM) demonstrated that global Refined Multiparty Session Types (RMPSTs) are an effective specification language for centralized MAVLink protocol enforcement, but suffered from two engineering failures: manual proof terms interleaved with protocol definitions, and an OCaml extraction backend whose managed runtime is incompatible with resource-constrained UAV hardware. We present Platum, a framework that addresses both failures with a minimal DSL requiring only the five semantic components of a global session type (sender, receiver, label, payload variable, refinement predicate), whose structural well-formedness conditions are confirmed via reflective decision procedures in Meta-F*. Confirmed specifications are compiled directly into flat, allocation-free C Finite State Machines (FSMs), deployed as centralized proxy monitors at the GCS/UAV communication boundary. Our evaluation demonstrates a 4x reduction in total monitor latency and lower memory overhead compared to DATUM, measured via ArduPilot SITL simulation.

Andrea Mondelli, Paul Gazzillo, Yan Solihin

One of the most prevalent source of side channel vulnerabilities is the secret-dependent behavior of conditional branches (SDBCB). The state-of-the-art solution relies on Constant-Time Expressions, which require high programming effort and incur high performance overheads. In this paper, we propose SeMPE, an approach that relies on architecture support to eliminate SDBCB without requiring much programming effort while incurring low performance overheads. The key idea is that when a secret-dependent branch is encountered, the SeMPE microarchitecture fetches, executes, and commits both paths of the branch, preventing the adversary from inferring secret values from the branching behavior of the program. To enable that, SeMPE relies on an architecture that is capable of safely executing both branch paths sequentially. Through microbenchmarks and an evaluation of a real-world library, we show that SeMPE incurs near ideal execution time overheads, which is the sum of the execution time of all branch paths of secret-dependent branches. SeMPE outperforms code generated by FaCT, a constant-time expression language, by up to a factor of 18x.