SibylFuzzer : stateful fuzzing for file systems

Abstract

Correct file system behavior is vital to developing robust higher-level software and applications. However, correctly and efficiently investigating the wide range of file system behavior makes testing file systems a difficult task. In this thesis, I designed and implemented SibylFuzzer, a stateful fuzzer for testing file system behavior. Sibyl- Fuzzer is based on SibylFS, a third-party system comprised of a model for acceptable file system behavior and a procedure for comparing real-life file system implementation behavior against that model. SibylFuzzer uses SibylFS in two ways: first, as a source of file system knowledge to produce in-depth and meaningful tests; second, as a correctness standard such that any disagreement with a real-life file system's behavior indicates a potential bug within the real-life file system. I implemented SibylFuzzer in OCaml and performed all tests on a Linux file system.