Understanding and automatically detecting conflicting interactions between smart home IoT applications

Abstract

Smart home devices provide the convenience of remotely control-ling and automating home appliances. The most advanced smart home environments allow developers to write apps to make smart home devices work together to accomplish tasks, e.g., home security and energy conservation. A smart home app typically implements narrow functionality and thus to fully implement desired functionality homeowners may need to install multiple apps. These different apps can conflict with each other and these conflicts can result in undesired actions such as locking the door during a fire. In this paper, we study conflicts between apps on Samsung SmartThings, the most popular platform for developing and deploying smart home IoT devices. By collecting and studying 198 official and 69 third-party apps, we found significant app conflicts in 3 categories: (1) close to 60% of app pairs that access the same device, (2) more than 90% of app pairs with physical interactions, and (3) around 11% of app pairs that access the same global variable. Our results suggest that the problem of conflicts between smart home apps is serious and can create potential safety risks. We then developed a conflict detection tool that uses model checking to automatically detect up to 96% of the conflicts.