Month: May 2015

  • Generating a Random Program vs. Generating All Programs

    Generating all possible inputs — up to some maximum length — to a software system is one way of creating test cases, and this technique even has a name: bounded exhaustive testing. Back when we were doing Csmith, my then-student Yang Chen spent a while on a bounded exhaustive C program generator which was in…

  • What afl-fuzz Is Bad At

    American fuzzy lop is a polished and effective fuzzing tool. It has found tons of bugs and there are any number of blog posts talking about that. Here we’re going to take a quick look at what it isn’t good at. For example, here’s a program that’s trivial to crash by hand, that afl-fuzz isn’t…