Tags: Augmenting Microkernel Messages with Lightweight Metadata

Abstract

In this work, we propose Tags, an e cient mechanism that augments microkernel interprocess messages with lightweight metadata to enable the development of new, systemwide functionality without requiring the modi cation of application source code. Therefore, the technology is well suited for systems with a large legacy code base and for third-party applications such as phone and tablet applications. As examples, we detailed use cases in areas consisting of mandatory security and runtime veri cation of process interactions. In the area of mandatory security, we use tagging to assess the feasibility of implementing a mandatory integrity propagation model in the microkernel. The process interaction veri cation use case shows the utility of tagging to track and verify interaction history among system components. To demonstrate that tagging is technically feasible and practical, we implemented it in a commercial microkernel and executed multiple sets of standard benchmarks on two di erent computing architectures. The results clearly demonstrate that tagging has only negligible overhead and strong potential for many applications.