Color My World: Deterministic Tagging for Memory Safety

Hardware-assisted memory protection features are increasingly being deployed in COTS processors. ARMv8.5 Memory Tagging Extensions (MTE) is a recent example, which has been used to provide probabilistic checks for memory safety. This use of MTE is not secure against the standard adversary with arbitrary read/write access to memory. Consequently MTE is used as a software development tool. In this paper we present the first design for deterministic memory protection using MTE that can resist the standard adversary, and hence is suitable for post-deployment memory safety. We describe our compiler extensions for LLVM Clang implementing static analysis and subsequent MTE instrumentation. Via a comprehensive evaluation we show that our scheme is effective.