Breaking and Protecting Linux Kernel Stack
Explore the evolution of Linux kernel stack attacks and defenses in this comprehensive conference talk. Delve into the history of stack-based vulnerabilities, examining existing protective measures implemented in the upstream Linux kernel. Analyze the effectiveness of current safeguards, including vmalloc-based stack allocation with guard pages, thread_info removal, and the STACKLEAK feature. Investigate the potential for further enhancing kernel stack security through RANDOMIZE_KSTACK_OFFSET, considering its challenges and performance implications. Gain insights into various attack techniques such as buffer overflows, stack overflows, and inter-stack exploitation, while learning about countermeasures like VMAP-based stacks and Variable-Length Arrays removal. Evaluate the gap between current protections and potential threats, and engage in a discussion on the future of Linux kernel stack security.