Linux Security Summit Europe 2025

Linux Virtualization based Security (LVBS) is a security feature that leverages hypervisors to a) harden the kernel and b) ensure that critical kernel resources remain untampered, even if the guest kernel gets compromised by creating an isolated environment that runs at a higher trust level than the normal operating environment. A key kernel integrity feature of LVBS is to ensure that kernel memory protections (read-only, W^X) are backed up by this trusted environment using Second Level Page Tables so that even if the guest kernel is compromised, the kernel memory cannot be tampered with.
One of the challenges in enabling hypervisor-enforced kernel memory protection is that the Linux kernel inherently supports features that either modify existing kernel code or inject code into the kernel memory space. In this talk, we aim to examine a comprehensive list of such kernel features (which are inherently easier exploit surfaces) and then discuss how these features can be hardened via LVBS to ensure that the integrity and authenticity of patched code, even if the kernel is compromised. Finally, we present the status of our work in implementing these hardenings.