249 research outputs found

    Working Sets Past and Present

    Get PDF

    Integrating Segmentation and Paging Protection for Safe, Efficient and Transparent Software Extensions

    Get PDF
    The technological evolution towards extensible software architectures and component-based software development demands safe, efficient, flexible, and easy-touse extension mechanisms to provide protection among software modules residing in the same address space. While a number of software-based approaches have been proposed in the last several years, no clear winner emerges that satisfactorily addresses all the design issues involved in establishing multiple protection domains within an address space. This paper describes the design, implementation, and evaluation of a novel intra-address space protection mechanism called Palladium, which is built upon the combined segmentation and paging protection hardware provided by Intel's X86 architecture. Based on the considerations on application programming and systems implementation complexity, we chose to use slightly different approaches to implement the user-level and kernel-level extension mechanisms. To demonstrate the resulting prototyp..

    CHERI: A hybrid capability-system architecture for scalable software compartmentalization

    Get PDF
    CHERI extends a conventional RISC Instruction- Set Architecture, compiler, and operating system to support fine-grained, capability-based memory protection to mitigate memory-related vulnerabilities in C-language TCBs. We describe how CHERI capabilities can also underpin a hardware-software object-capability model for application compartmentalization that can mitigate broader classes of attack. Prototyped as an extension to the open-source 64-bit BERI RISC FPGA softcore processor, FreeBSD operating system, and LLVM compiler, we demonstrate multiple orders-of-magnitude improvement in scalability, simplified programmability, and resulting tangible security benefits as compared to compartmentalization based on pure Memory-Management Unit (MMU) designs. We evaluate incrementally deployable CHERI-based compartmentalization using several real-world UNIX libraries and applications.We thank our colleagues Ross Anderson, Ruslan Bukin, Gregory Chadwick, Steve Hand, Alexandre Joannou, Chris Kitching, Wojciech Koszek, Bob Laddaga, Patrick Lincoln, Ilias Marinos, A Theodore Markettos, Ed Maste, Andrew W. Moore, Alan Mujumdar, Prashanth Mundkur, Colin Rothwell, Philip Paeps, Jeunese Payne, Hassen Saidi, Howie Shrobe, and Bjoern Zeeb, our anonymous reviewers, and shepherd Frank Piessens, for their feedback and assistance. This work is part of the CTSRD and MRC2 projects sponsored by the Defense Advanced Research Projects Agency (DARPA) and the Air Force Research Laboratory (AFRL), under contracts FA8750-10-C- 0237 and FA8750-11-C-0249. The views, opinions, and/or findings contained in this paper are those of the authors and should not be interpreted as representing the official views or policies, either expressed or implied, of the Department of Defense or the U.S. Government. We acknowledge the EPSRC REMS Programme Grant [EP/K008528/1], Isaac Newton Trust, UK Higher Education Innovation Fund (HEIF), Thales E-Security, and Google, Inc.This is the author accepted manuscript. The final version is available at http://dx.doi.org/10.1109/SP.2015.
    • …
    corecore