Overshadow: A Virtualization-Based Approach to Retrofitting Protection in Commodity Operating Systems
Authors: M. Chen, P. Subrahmanyam, C. Waldspurger, E. C. Lewis, Tal Garfinkel, D. Boneh, D. Ports, and J. Dwoskin
Abstract:
Commodity operating systems entrusted with securing sensitive
data are remarkably large and complex, and consequently, frequently
prone to compromise. To address this limitation, we introduce
a virtual-machine-based system called Overshadow that
protects the privacy and integrity of application data, even in the
event of a total OS compromise. Overshadow presents an application
with a normal view of its resources, but the OS with an encrypted
view. This allows the operating system to carry out the
complex task of managing an application's resources, without allowing
it to read or modify them. Thus, Overshadow offers a last
line of defense for application data.
Overshadow builds on multi-shadowing, a novel mechanism that presents different views of "physical" memory, depending on the context performing the access. This primitive offers an additional dimension of protection beyond the hierarchical protection domains implemented by traditional operating systems and processor architectures.
We present the design and implementation of Overshadow and show how its new protection semantics can be integrated with existing systems. Our design has been fully implemented and used to protect a wide range of unmodified legacy applications running on an unmodified Linux operating system. We evaluate the performance of our implementation, demonstrating that this approach is practical.
Reference:
In proceedings of ACM ASPLOS 2008, pp. 2-13
Full paper: pdf [first posted 1/2008 ]