Fuzzing the rust evm

This provides a simple fuzzing harness that can be used a start when fuzzing the rust evm. The fuzzer will take a byte input from honggfuzz, split it at a fixed delimiter and give some of it as code and some of it as data to the evm.

Running the fuzzer

Run the fuzzer like so:

cargo hfuzz run evm_fuzz

Honggfuzz saves the fuzzing queue in the directory hfuzz_workspace/evm_fuzz/input. To debug the fuzzer, you can also compile the fuzzer as a normal binary via cargo build. Then, to debug a certain input in the fuzzing queue, run ./target/debug/evm_fuzz hfuzz_workspace/evm_fuzz/input/<file>

Notes

Because this fuzzer does not implement any gasometer, honggfuzz will report some timeouts. A reasonable approach to improve the perfomance would be to extend this fuzzer with a gasometer.