Cog/Frameworks/OpenMPT/OpenMPT/contrib/fuzzing

libopenmpt fuzz suite

In this directory, you can find the necessary tools for fuzzing libopenmpt with the American Fuzzy Lop fuzzer (afl-fuzz).

Contents:

• all_formats.dict: A dictionary containing magic bytes from all supported module formats to make the life of the fuzzer a bit easier.
• fuzz-master.sh: Script to launch the main fuzzing process. If you want to use just one fuzzer instance, run this one.
• fuzz-slave.sh: Script to launch the secondary fuzzing process. It is recommended to run at least two fuzzer instances, as the deterministic and random fuzz mode have been found to complement each other really well.
• fuzz-settings.sh: Set up your preferences and afl settings here before the first run.
• fuzz.c: A tiny C program that is used by the fuzzer to test libopenmpt.
• get-afl.sh: A simple script to obtain the latest version of the fuzzer.

Prerequisites

• afl from http://lcamtuf.coredump.cx/afl/ - the makefile expects this to be installed in contrib/fuzzing/afl, as it is automatically done by the get-afl.sh install script.
• Clang with LLVM dev headers (llvm-config needs to be installed). afl also works with gcc, but our makefile has been set up to make use of afl's faster LLVM mode.

How to use

• Run get-afl.sh, or manually extract afl to contrib/fuzzing/afl, use make to build afl-fuzz, cd llvm_mode, make to build afl-clang-fast. If building with either option fails because llvm-config cannot be found, try prepending LLVM_CONFIG=/usr/bin/llvm-config-3.8 or similar, and read the afl manual.
• Build libopenmpt with the build.sh script in this directory.
• Set up fuzz-settings.sh to your taste. Most importantly, you will have to specify the input directory for first use. The default setup mounts a tmpfs folder for all temporary files. You may change this behaviour if you do not have root privileges.
• Run fuzz-master.sh for the first (deterministic) instance of afl-fuzz.
• For a "slave" instance to run on another core, run fuzz-slave.sh.
• If you want to make use of even more cores, make a copy of fuzz-slave.sh and adjust "infile02" / "fuzzer02" to "infile03" / "fuzzer03" (they need to be unique)