Specifying fuzzing duration dynamically

[bcmills]

I've been trying to figure out how to configure the fuzzing duration dynamically for tests using Jazzer's JUnit integration.

I found:

• The JUnit Integration documentation doesn't mention fuzzing duration at all.

• The @FuzzTest annotation supports a maxDuration parameter, but it seems to only accept static strings.

• It appears to be possible to thread a duration down to libFuzzer via jazzer.internal.arg properties, but the name internal suggests that those are not intended to be user-facing. 😅

Is there a supported API for specifying a fuzz duration dynamically? If not, can one be added?

[simonresch]

Hi @bcmills,

you are correct that currently the only way to dynamically configure the fuzzing duration for JUnit executed fuzz tests is by passing flags directly to libFuzzer. This is discouraged with the internal prefix because not all libFuzzer arguments will play nicely with Jazzer specific settings, however for configuring the fuzzing duration it should be fine.

We are discussing adding a dedicated option to configure the fuzzing duration as a Jazzer option since it sounds like a common enough use case.