Linux Kernel Defence Map

Intro

Linux kernel security is a very complex topic. Some defence technologies are provided by the Linux kernel mainline. Others are going out‑of‑tree for various reasons (some of them are commercial, for example). Plus there are kernel defences that depend on special hardware features.

It would be nice to have a graphical representation of the current state of Linux kernel security.

So I've created a Linux Kernel Defence Map showing the relationships between:

• Vulnerability classes
• Exploitation techniques
• Bug detection mechanisms
• Defence technologies

N.B. The node connections don't mean "full mitigation." Rather, each connection represents some kind of relationship. So this map should help to navigate the documentation and Linux kernel sources. It also provides the Common Weakness Enumeration (CWE) numbers for vulnerability classes.

How this Map is made

This map is written in the DOT language, which makes maintenance and updating in Git very convenient. The diagram is generated using GraphViz with the following command:

dot -Tsvg linux-kernel-defence-map.dot -o linux-kernel-defence-map.svg

Do you want to check your kernel config?

So there are plenty of security hardening options in the Linux kernel. A lot of them are not enabled by the major distros. We have to enable these options ourselves to make our systems more secure.

But nobody likes verifying configs manually. So I've created the kconfig-hardened-check that checks security hardening options of the Linux kernel. You are welcome to try it.

Documentation

• Grsecurity features:

  https://grsecurity.net/features.php

• The State of Kernel Self Protection by Kees Cook:

  https://outflux.net/slides/2018/lca/kspp.pdf

• Linux kernel security documentation:

  https://www.kernel.org/doc/html/latest/security/self-protection.html

• Linux kernel mitigation checklist by Shawn C:

  https://github.com/hardenedlinux/grsecurity-101-tutorials/blob/master/kernel_mitigation.md

• Trends, challenge, and shifts in software vulnerability mitigation by MSRC:

  https://github.com/Microsoft/MSRC-Security-Research/tree/master/presentations/2019_02_BlueHatIL

• Pursuing Durable Safety for Systems Software by Matt Miller @mamillmsft:

  https://www.sstic.org/2020/presentation/ouverture_2020/

• A Decade of Linux Kernel Vulnerabilities, their Mitigation and Open Problems by Abhilash Raj:

  https://github.com/maxking/linux-vulnerabilities-10-years

• Linux Kernel Runtime Guard (LKRG) threat model:

  https://openwall.info/wiki/p_lkrg/Threat_model

• Spectre & Meltdown Checker by Stéphane Lesimple @speed47

  https://github.com/speed47/spectre-meltdown-checker

Map for Linux kernel v5.12