RContainer: A Secure Container Architecture through Extending ARM CCA Hardware Primitives

—Containers have become widely adopted in cloud platforms due to their efficient deployment and high resource utilization. However, their weak isolation has always posed a significant security concern. In this paper, we propose RContainer, a novel secure container architecture that protects containers from untrusted operating systems and enforces strong isolation among containers by extending ARM Confidential Computing Architecture (CCA) hardware primitives. RContainer introduces a small, trusted mini-OS that runs alongside the deprivileged OS, responsible for monitoring the control flow between the operating system and containers. Additionally, RContainer uses shim-style isolation, creating an isolated physical address space called con-shim for each container at the kernel layer through the Granule Protection Check mechanism. We have implemented RContainer on ARMv9-A Fixed Virtual Platform and ARMv8 hardware SoC for security analysis and performance evaluation. Experimental results demonstrate that RContainer can significantly enhance container security with a modest performance overhead and a minimal Trusted Computing Base (TCB).