Enabling Hardware-Assisted Shields for Linux Security Subsystems - Zahra Tarkhani, Microsoft
Channel: The Linux Foundation
Date: 2023-10-04

Enabling Hardware-Assisted Shields for Linux Security Subsystems - Zahra Tarkhani, Microsoft

Linux security subsystems, such as LSMs, are widely used in a wide range of applications and systems protection. However, the security of these critical subsystems depends only on the kernel with a very large attack surface, which allows applications with higher privileges or root access to bypass or disable them. In this talk, we introduce a defence-in-depth mechanism for hardening these critical subsystems in the presence of a privileged attacker (e.g., with root access or compromised kernel). This talk introduces a Linux kernel abstraction that utilizes hardware CHERI capabilities (which provides fine-grained privilege separation on Morello architecture) and hypervisor-enforced integrity protection to achieve this. We explain the difference between these two enforcement mechanisms from a security, architecture and performance perspective as well as kernel changes required to enable this hardening feature.