Hardware-Assisted Control-Flow Integrity Enhancement for IoT Devices

Internet of Things (IoT) devices face an escalating threat from code reuse attacks (CRAs) as they can reuse existing code for malicious purpose. Thus a practical cost-effective Control-Flow Integrity (CFI) mechanism for IoT devices is urgently needed. However, existing CFI solutions suffer from impractical-ities, including high performance overhead and a heavy reliance on offline perfect Control-Flow Graph (CFG) generation. To tackle these challenges, we propose a fine-grained dependable CFI scheme for IoT devices that real-time updates the CFG of devices. We evaluate the implementation on RISC-V architectures and the results show that our CFI scheme provides both backward- and forward-edge protection with almost no performance overhead in the case of fixed CFG, negligible power overhead, and low hardware overhead. Compared to the current hardware-assisted CFI designs, our design eliminates the dependence on the offline perfect CFG generation and performs real-time CFG updating for better practicality.