Look Before You Access: Efficient Heap Memory Safety for Embedded Systems on ARMv8-M

Numerous embedded systems utilize firmware written in memory-unsafe C/C++. So, the firmware may exhibit spatial memory vulnerabilities, such as buffer overflows, which, if exploited by an attacker, can lead to various software attacks. While several studies have proposed defenses against these memory vulnerabilities, they often introduce significant performance and memory overhead or are impractical for application in embedded systems. In this paper, we introduce micro-fat pointer, a novel solution for heap memory safety for embedded systems. Notably, micro-fat pointer leverages TT instructions newly introduced in ARMv8-M to implement an efficient bounds-checking mechanism. Our evaluation results demonstrate that micro-fat pointer exhibits a 41% performance improvement compared to the existing state-of-the-art heap memory safety solution.