Abstract:
File systems are a crucial component of any modern operating system, whether it is a general-purpose computing system or a specialized data storage system. The cost of a file system error is very high; consequently, there is a need for effective tools for analyzing quality and detecting errors in file systems. This paper presents the DIFFuzzer tool, which is based on fuzzing techniques using grey-box and black-box principles, and implements a differential dynamic analysis approach, where the behavior of the target file system is compared to that of another, known to be of higher quality file system, which serves as a generator of reference behavior. In comparing behaviors, both the response codes of system calls and the aggregated state of the file systems are analyzed. The toolkit also includes a reducer that minimizes the erroneous trace and generates a short fragment where the error still appears. The developed tool has been tested on several POSIX-compliant file systems and has discovered several errors even during a relatively short experiment.
Keywords:file systems, differential fuzzing, file system testing, grey-box fuzzing
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