The CHERI capability model: Revisiting RISC in an age of risk

Add to your list(s) Download to your calendar using vCal

• Jonathan Woodruff (University of Cambridge)
• Thursday 05 June 2014, 15:00-16:00
• FW26, Computer Laboratory, William Gates Builiding.

If you have a question about this talk, please contact Eiko Yoneki.

Motivated by contemporary security challenges, we reevaluate and refine capability-based addressing for the RISC era. We present CHERI , a hybrid capability model that extends the 64-bit MIPS ISA with byte-granularity memory protection. We demonstrate that CHERI enables language memory model enforcement and fault isolation in hardware rather than software, and that the CHERI mechanisms are easily adopted by existing programs for efficient in-program memory safety.

In contrast to past capability models, CHERI complements, rather than replaces, the ubiquitous page-based protection mechanism, providing a migration path towards deconflating data-structure protection and OS memory management. Furthermore, CHERI adheres to a strict RISC philosophy: it maintains a load-store architecture and requires only single-cycle instructions, and supplies protection primitives to the compiler, language runtime, and operating system.

We demonstrate a mature FPGA implementation that runs the FreeBSD operating system with a full range of software and an open-source application suite compiled with an extended LLVM to use CHER Imemory protection. A limit study compares published memory safety mechanisms in terms of instruction count and memory overheads. The study illustrates that CHERI is performance-competitive even while providing assurance and greater flexibility with simpler hardware.

This talk is part of the Computer Laboratory Systems Research Group Seminar series.

This talk is included in these lists:

• All Talks (aka the CURE list)
• CL's SRG seminar
• Cambridge Centre for Data-Driven Discovery (C2D3)
• Cambridge talks
• Chris Davis' list
• Computer Laboratory Systems Research Group Seminar
• Department of Computer Science and Technology talks and seminars
• FW26, Computer Laboratory, William Gates Builiding
• Interested Talks
• School of Technology
• Trust & Technology Initiative - interesting events
• bld31
• ndk22's list
• ob366-ai4er
• rp587

Note that ex-directory lists are not shown.