How to reproduce OOM failures when using FuzzedDataProvider

[centic9]

Hi,

When an OOM is produced as part of fuzzing, no reproducer-code is generated.

When you are using a byte[] as fuzz-data, creating a reproducer is easy, but I did not see how to do this when using a FuzzedDataProvider.

Is there an example of how to read the data so that it can be used to re-run the fuzzing-target with this data?

When I try to use the Base64 encoded string that is printed together with a CannedFuzzedDataProvider, it fails with a StreamCorruptedException:

        String base64 = "...";

        CannedFuzzedDataProvider provider = new CannedFuzzedDataProvider(base64 /*new String(encode, StandardCharsets.UTF_8)*/);

        Fuzz.fuzzerTestOneInput(provider);

[fmeum]

We recommend using the JUnit 5 support to write your fuzz test. Even with OOM crashes, you can run and debug all collected crash-* files directly as regular parameterized unit test cases. Existing fuzz tests can be reused with essentially no changes (just add @FuzzTest and move them to a test class).

If that doesn't work, you can use the Jazzer replayer to run a given fuzz test class on a given crash-* file. We have deprecated it in favor of the JUnit approach, but it should continue to work.

[centic9]

Thanks, the @fuzztest is exactly what I was looking for!