State of Linux Desktop Security

I made a tweet claiming that Linux is behind on security mitigations. This post is to outline mitigations added to platforms such as Windows, MacOS, and even ChromeOS that have yet to see the light of day on the linux desktop.

(Btw, Andrew Kelley is my hero!)

Linux distros are behind on implementing modern binary exploit mitigations. The last thing Linux userspace has done is ASLR/PIE and stack canaries: this hasen't changed for years. Windows and MacOS enforce signature checking on all binaries. glibc's allocator is primitive compared to LLVM's Scudo allocator, which mitigates use-after-frees and heap overflows.

Windows signs heap pages to ensure they're immutable, in addition to hardware-enforced control flow protection. Modern iOS does this too. Windows also implemented something exciting called a shadow stack, which stores return addresses in a secret, seperate stack from local variables. This is both faster and more secure than stack cookies.

Linux distros have no concept of sandboxing, or any meaningful application security model. Any app running under Xorg can see the contents of any other app runing under Xorg. Flatpack and snap are both security nightmares , fundamentally flawed and poorly implemented. The only good sandoxing API provided by the Linux kernel is seccomp-bpf, and the only program that uses it is Google Chrome/Chromium. To compare, ChromeOS requires every service to have its own seccomp filter .

Also a friendly reminder that Debian is always behind on CVEs, and I'm sure that most distros don't fare any better.