Space sharing services like vacation rentals are being equipped with smart devices. However, sharing of such devices has privacy and security problems due to no or unclear control transfer between owners and users. In this paper, we propose Spacelord, a system to time-share smart devices contained in a shared space privately and securely while allowing users to configure them. When a user stays at a space, Spacelord ensures that the smart devices contained in it run code and configurations the user trusts while removing pre-installed code and configurations. When the user leaves the space, Spacelord reverts any changes the user has introduced to the smart devices to delete remaining private data and let the owner take back control over the devices. We evaluate Spacelord for two realistic space-sharing cases—smart home and coworking meeting room—and observe reasonable provisioning delay and runtime overhead.

Rust is a promising system programming language that guarantees memory safety at compile time. To support diverse requirements for system software such as accessing low-level hardware, Rust allows programmers to perform operations that are not protected by the Rust compiler with the unsafe keyword. However, Rust's safety guarantee relies on the soundness of all unsafe code in the program as well as the standard and external libraries, making it hard to reason about their correctness. In other words, a single bug in any unsafe code breaks the whole program's safety guarantee.