FastCFI: Real-time Control-Flow Integrity Using FPGA without Code Instrumentation

Abstract

Control-Flow Integrity (CFI) is an effective defense technique against a variety of memory-based cyber attacks. CFI is usually enforced through software methods, which entail considerable performance overhead. Hardware-based CFI techniques can largely avoid performance overhead, but typically rely on code instrumentation, forming a non-trivial hurdle to the application of CFI. Taking advantage of the tradeoff between computing efficiency and flexibility of FPGA, we develop FastCFI, an FPGA-based CFI system that can perform fine-grained and stateful checking without code instrumentation. We also propose an automated Verilog generation technique that facilitates fast deployment of FastCFI, and a compression algorithm for reducing the hardware expense. Experiments on popular benchmarks confirm that FastCFI can detect fine-grained CFI violations over unmodified binaries. When using FastCFI on prevalent benchmarks, we demonstrate its capability to detect fine-grained CFI violations in unmodified binaries, while incurring an average of 0.36% overhead and a maximum of 2.93% overhead.