Internals of Landlock: a new kind of Linux Security Module leveraging eBPF

In this talk we explain the constraints and choices that led to the design of Landlock, a new Linux Security Module (LSM) proposal designed to let unprivileged users enforce their own security policy. Landlock has multiple new properties that can complete those of the current major LSMs (e.g. SELinux). Leveraging the eBPF engine, Landlock can apply multiple access controls and make them evolve over time, enabling developers to manage security policy per application instead of dealing with access-control rules defined for the whole system. We answer some questions such as: What are the constraints and good practices to properly extend the Linux kernel? How Landlock uses eBPF with the LSM framework? What are the required restrictions to express a security policy, with a bytecode like eBPF, in a safe way? We also show a new demo highlighting the dynamic aspect of Landlock.

This talk is intended to be a deep dive into some internals of Landlock. For a more general introduction to Landlock, you can get a look at https://landlock.io (FOSDEM 2018). 

Mickaël Salaün 
Mickaël is a security researcher, software developer and open source enthusiast. He is mostly interested in Linux-based operating systems, especially from a security point of view. He has built security sandboxes (e.g. StemJail) before hacking into the kernel on a new LSM called Landlock. He is currently employed by the French Network and Information Security Agency (ANSSI).