grsecurity

Quick reminder that our 6.8 short-term stable kernel goes EOL at the end of this month. Some stats: over the period of a year, it included over 1500 security/stability-relevant backports.

Nice demo: tested a vulnerable Ubuntu 22.04 system for glibc CVE-2025-4802 using Solar Designer's PoC adapted to Ubuntu (replace any occurrence of "myhostname" with "mdns4_minimal"). Even an old #grsecurity 5.4.96 kernel from February 8 2021 prevented exploitation

It's now available!

We expect our 6.13 #grsecurity beta to be available within the next two weeks.

AMD: Microcode Signature Verification Vulnerability ### Summary Google Security Team has identified a security vulnerability in some AMD Zen-based CPUs. This vulnerability allows an adversary with local administrator privileges (ring 0 from outside...

github.com/google/secur...

Our 6.12 #grsecurity beta is now available to beta testers for testing

Slides for Pawel's H2HC presentation this month on the TLB are now available on grsecurity.net/papers
If you've never heard of "paging-structure caches" before, check it out!

We need to post a correction to yesterday's eBPF performance numbers:
Mathias Krause wasn't happy with just a 30x speedup and took a look at one final bottleneck that was bothering him.
The speedup over vanilla is now 747x 🤯 (5.27s vs 1h5m40s)

Testcase fixes were sent upstream by Mathias Krause here: lore.kernel.org/bpf/20241104...

If you're curious, we also fixed the failing vanilla testcases, without which the speedup would have appeared even larger than 30x. Every grsecurity option really means every single one, including RAP, PRIVATE_KSTACKS, KERNEXEC, UDEREF, AUTOSLAB, KERNSEAL, etc.

Performance isn't the enemy of security: we care about both. Today's patches finish off a set of security/performance improvements to eBPF. Below we show a ~30x speedup vs vanilla in running the eBPF selftests with every single #grsecurity option enabled!

Johannes Wikner has published a detailed walkthrough of the first cross-process Spectre exploit against a real target, an attack he developed in part during his internship with us last year.
Check it out here: grsecurity.net/cross_proces...

A new version of paxctld (1.2.6) is now available for download!