Color reclamation for heap memory coloring scheme in PIPE tagged-memory architecture

Abstract

Memory safety violations remain a significant hurdle as people try to secure computer software. The PIPE project proposed an approach to securing software by tagging memory and registers with color tags and defining policies in terms of the tags to disallow instructions violating memory safety. However, the PIPE project did not include a scheme for reclaiming and reusing allocated color tags, thus resulting in issues including color wrap-arounds. This thesis proposes a scheme for reclaiming and reusing color tags within the PIPE tagged-memory architecture. The proposed scheme is then evaluated on a combination of synthetic microbenchmarks and real-world allocation trace replays. Evaluation results show that the reclaimer can effectively reclaim colors in all cases, and in some cases can also improve performance by increasing rule cache hit rate.