javan-warty-pig

A little while back I wrote something similar[0]. Basically I applied AFL principles to the JVM by similarly implementing bytecode instrumentation in the lightest way I could and having "passes" of sorts that manipulated inputs using stages like AFL does. The readme explains the implementation details (I don't really maintain it or use it anymore and I never even published it to Maven, so it has old invalid jitpack links, but the code is quite solid). 0 - https://github.com/cretz/javan-warty-pig

Last I reviewed, the mutations only fell through to "random havoc" after other stages were tried. So for each mutation, there are deterministic bit flips, number adds, "interesting" numbers set, dictionary uses, and only _then_ does it start the random havoc stage on the mutation. So it's not all random and you can start it with whatever value you want via dictionary or other. (I kinda made a Java version https://github.com/cretz/javan-warty-pig that attempts to mimic this logic)

I couldn't find any good AFL-like fuzzers for Java, so I wrote one not too long ago: https://github.com/cretz/javan-warty-pig. Feel free to take it and hack/reuse it.

For anyone interested on the JVM side, I wrote a fuzzer last year using afl-like logic: https://github.com/cretz/javan-warty-pig

Tangentially related, speaking of Java, I wrote a path guided one recently for code running on the JVM: https://github.com/cretz/javan-warty-pig. It's found bugs for me on internal things, but I haven't run it on anything popular to build a trophy case.

> so they went with signed only types Except chars > At least Java 8 introduced unsigned math helper methods. They still aren't enough IMO. They don't have way ways to take LE/BE bytes out of integers or vice versa (not worth creating ByteBuffer for). I always end up recreating these utilities in projects where it isn't worth depending on or shading an entire Guava, e.g. [0] 0 - https://github.com/cretz/javan-warty-pig/blob/master/fuzz/sr...