Multi Layer Archive

Fuzzing

A fuzzing scenario made with afl.rs is available in mla-fuzz-afl. The scenario is capable of:

• Creating archives with interleaved files, and different layers enabled
• Reading them to check their content
• Repairing the archive without truncation, and verifying it
• Altering the archive raw data, and ensuring reading it does not panic (but only fail)
• Repairing the altered archive, and ensuring the recovery doesn't fail (only reports detected errors)

To launch it:

1. produce initial samples by uncommenting produce_samples() in mla-fuzz-afl/src/main.rs

cd mla-fuzz-afl
# ... uncomment `produces_samples()` ...
mkdir in
mkdir out
cargo run

2. build and launch AFL

cargo afl build
cargo afl fuzz -i in -o out ../target/debug/mla-fuzz-afl

If you have found crashes, try to replay them with either:

• Peruvian rabbit mode of AFL: cargo afl run -i - -o out -C ../target/debug/mla-fuzz-afl
• Direct replay: ../target/debug/mla-fuzz-afl < out/crashes/crash_id
• Debugging: uncomment the "Replay sample" part of mla-fuzz-afl/src/main.rs, and add dbg!() when it's needed

:warning: The stability is quite low, likely due to the process used for the scenario (deserialization from the data provided by AFL) and variability of inner algorithms, such as brotli. Crashes, if any, might not be reproducible or due to the mla-fuzz-afl inner working, which is a bit complex (and therefore likely buggy). One can comment irrelevant parts in mla-fuzz-afl/src/main.rs to ensure a better experience.