Information flow control for concurrent covert termination and timing channels

Alejandro Russo

Dept. of Computer Science and Engineering
Chalmers University of Technology

Monday, 21 May 2012, 10:00 (note the ununusual weekday and time)
Cybernetica Bldg (Akadeemia tee 21), room C330

Abstract: When termination of a program is observable by an adversary, confidential information may be leaked by terminating accordingly. While this termination covert channel has limited bandwidth for sequential programs, it is a more dangerous source of information leakage in concurrent settings. We address concurrent termination and timing channels by presenting an information-flow control system that mitigates and eliminates these channels while allowing termination and timing to depend on secret values. Intuitively, we leverage concurrency by placing such potentially sensitive actions in separate threads. While termination and timing of these threads may expose secret values, our system requires any thread observing these properties to raise its information-flow label accordingly, preventing leaks to lower-labeled contexts. We develop our approach in a Haskell library and demonstrate its applicability by implementing a web server that uses information-flow control to restrict untrusted web applications.

This talk is based on joint work in progress with Deian Stefan, Pablo Buiras, Amit Levy, John C. Mitchell, and David Maziéres.

Tarmo Uustalu
Last update 15.5.2012