Verifying Information Flow Control Over Unbounded Processes

William R. Harris, Nicholas A. Kidd, Sagar Chaki, Somesh Jha, and Thomas Reps

Decentralized Information Flow Control (DIFC) systems enable programmers to express a desired DIFC policy, and to have the policy enforced via a reference monitor that restricts interactions between system objects, such as processes and files. Past research on DIFC systems focused on the reference-monitor implementation, and assumed that the desired DIFC policy is correctly specified. The focus of this paper is an automatic technique to verify that an application, plus its calls to DIFC primitives, does indeed correctly implement a desired policy. We present an abstraction that allows a model checker to reason soundly about DIFC programs that manipulate potentially unbounded sets of processes, principals, and communication channels. We implemented our approach and evaluated it on a set of real-world programs.

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