Fuzzing FreeBSD w/ AFL

This project is used to store the various information and scripts that I have used in fuzzing FreeBSD.

This project started when someone reported that fsck_ffs couldn’t repair a file system they had, but as we all know, file systems are often large, and contain data the people don’t want to share, making getting test cases more difficult than most. I decided to see if fuzzing was able to reproduce their failure, and the very first failure was the reported, but it also managed to find some more.

Building

There is a script build.sh that will set the compiler correctly when building parts of the FreeBSD source tree. You do have to be careful when doing this as there are sometimes dependencies that need to be built as well, e.g. libufs for fsck_ffs.