Memory Segmentation to Support Secure Applications

Current CPU architectures provide only weak support for software seg-mentation, a key underpinning for software security techniques such as sandboxing, managed languages, and static analysis. Because hardware memory segmentation is relevant mainly in the program abstraction its support has been deemphasized in modern operating systems, yet mod-ern hardware requires operating system support to use its segmentation features. This paper argues that by implementing a capability model, it is possible to safely support creation, distribution and use of segments purely in user space. Hardware support for user-mode segmentation would enable efficient sandboxing within processes, enforcement of com-piler structure, managed languages, and formal verification of machine code. We present a working prototype of such a system implemented on an FPGA and running FreeBSD.