Go With the FLOW: Fine-Grained Control-Flow Integrity for the Kernel

Abstract

This paper describes FLOW: a fine-grained control-flow integrity (CFI) implementation that focuses on protecting the Linux kernel. By combining source-code and binary analysis, FLOW maps valid execution paths into a fine-grained control-flow graph, which is later used to instrument the kernel with label-based CFI checks that prevent control-flow hijacking attacks. FLOW induces an average overhead of 17% on system call latency and 5% on I/O throughput, while its impact on real-world applications is ≈ 1%.