Add Dictionary/Extras Support

[domenukk]

The main feature lacking in LibAFL right now is Extas support. This includes the dictionary extras, you would pass to AFL using -x, but also autoextras added during fuzzing, as well as the compile-time autodict feature in AFL LTO builds, and eventually even cmplog. The important pieces of code are in https://github.com/AFLplusplus/AFLplusplus/blob/stable/src/afl-fuzz-extras.c

[rish9101]

I was looking at doing this. Can you give a little background of how afl generates extras during the fuzzing? taking a dict as a command-line parameter and parsing is pretty straight-forward. But generating them during fuzzing was a bit confusing :sweat_smile:

[domenukk]

We can start with the "normal" ones and go from there :)

[rish9101]

Ok. So, if we get a dict, do we need any special mutators for them? Or the havoc ones work(for now)?

[domenukk]

Havoc needs to take extras into account, that's okay for now. Later we'll probably want redqueen

[rish9101]

:+1: I think we'll need a deterministic stage too now?

[domenukk]

If we want to be close to AFL, eventually yes

[rish9101]

I've started with the deterministic stage and deterministic mutators (Had to introduce a new structure for storing "state" of mutation since it isn't random). You guys can have a look at add_extras branch

[andreafioraldi]

Don't code, I have the lock this week, deterministic can be implemented just using the stage_idx parameter to mutate (that was in FFF for this purpose, but was not ported to LibAFL)