WHISTLE: CPU Abstractions for Hardware and Software Memory Safety Invariants

Memory safety invariants extracted from a program can help defend and detect against both software and hardware memory violations. For instance, by allowing only specific instructions to access certain memory locations, system can detect out-of-bound or illegal pointer dereferences that lead to correctness and security issues. In this paper, we propose CPU abstractions, called WHISTLE , to specify and check program invariants to provide defense mechanism against both software and hardware memory violations at runtime. WHISTLE ensures that the invariants must be satisfied at every memory access. We present a fast invariant address translation and retrieval scheme using a specialized cache. It stores and checks invariants related to global, stack and heap objects. The invariant checks can be performed synchronously or asynchronously. WHISTLE uses synchronous checking for high security-critical programs, while others are protected by asynchronous checking. A fast exception is proposed to alert any violations as soon as possible in order to close the gap for transient attacks. Our evaluation shows that WHISTLE can detect both software and hardware, spatial and temporal memory violations. WHISTLE incurs 53% overhead when checking synchronously, or 15% overhead when checking asynchronously.