Friendly Fire

IoT platforms enable users to connect various smart devices and online services via reactive apps running on the cloud. These apps, often developed by third-parties, perform simple computations data triggered external information sources actuate results of sinks. Recent research shows that unintended or malicious interactions between different (even benign) a user can cause severe security safety risks. works leverage program analysis techniques build tools for unveiling unexpected interference across specific use cases. Despite these initial efforts, we are still lacking semantic framework understanding apps. The question what policy cross-app embodies remains largely unexplored. This article proposes capturing essence in platforms. generalizes connects syntactic enforcement mechanisms bisimulation-based notions security, thus providing baseline formulating soundness criteria mechanisms. Specifically, present calculus models behavioral semantics system executing concurrently, it define desirable policies targeting To demonstrate usefulness our framework, implement static analyses enforcing safety, prove them sound with respect conditions. We also real-world validate practical benefits based proposed