Resources

People often ask me "How did you learn how to hack?" The answer: by reading. This page is a collection of the blog posts and other articles that I have accumulated over the years of my journey. Enjoy!

The authors of this post were reviewing OpenVP2 when faced with a difficult challenge: it had over 2.5K compiler warnings. Could some of these be security issues though? Their goal was to limit these errors to only the ones that matter. They decided to tackle a single class of issues: numerical conversions.

C's relaxed type system allows for implicit numerical conversions. Not all conversions are security issues but some of them can be. Signedness, truncation and overflows are all issues that can arise from this. With this problem defined, they decided to build a CodeQL query to identify potentially problematic areas.

After performing all of this analysis, they determined that none of the conversions led to real issues. It's interesting to see the usage of more niche CodeQL queries to perform useful flow analysis. Good blog post!