The seL4 Proofs
The formal proofs for seL4 are hosted at https://github.com/seL4/l4v.
They are written in the Isabelle/HOL theorem prover, and some familiarity with this tool is required to understand them. There are many learning resources available for Isabelle – see the Isabelle website for tutorials and reference manuals, and this blog post for a list of what you’d need to really get deep into the proofs.
There are also many publications about these proofs, some of which are fairly complex. A comprehensive technical overview is available in the 2014 TOCS paper. It’s been a few years since then, but the technical concepts are still current.
The repository README file shows which proofs are where, and how to set up your machine to run them. You can run and check that the proofs work for a specific version of seL4 without a deep understanding of their content – that is one of the advantages of machine-checked proofs.
We’re planning to add more pointers to this page on how to get started on smaller contributions. Stay tuned for updates and feel free to raise pull requests to add more information yourself!