Overshadow: A Virtualization-Based Approach to Retrofitting Protection in Commodity Operating Systems

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“Overshadow: A Virtualization-Based Approach to Retrofitting Protection in Commodity Operating Systems” by Xiaoxin Chen, Tal Garfinkel, E. Christopher Lewis, Pratap Subrahmanyam, Carl A. Waldspurger, Dan Boneh, Jeffrey Dwoskin, and Dan R. K. Ports. In Proceedings of the 13th International Conference on Architectural Support for Programming Languages and Operating Systems (ASPLOS '08), (Seattle, WA, USA), Mar. 2008.

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.

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BibTeX entry:

@inproceedings{overshadow-asplos08,
   author = {Xiaoxin Chen and Tal Garfinkel and E. Christopher Lewis and
	Pratap Subrahmanyam and Carl A. Waldspurger and Dan Boneh and
	Jeffrey Dwoskin and Dan R. K. Ports},
   title = {Overshadow: A Virtualization-Based Approach to Retrofitting
	Protection in Commodity Operating Systems},
   booktitle = {Proceedings of the 13th International Conference on
	Architectural Support for Programming Languages and Operating
	Systems (ASPLOS '08)},
   address = {Seattle, WA, USA},
   month = mar,
   year = {2008}
}