Sound and precise cross-layer data flow tracking

Abstract

We connect runtime monitors for data flow tracking at different abstraction layers (a browser, a mail client, an operating system) and prove the soundness of this generic model w.r.t. a formal notion of explicit information flow. This allows us to (1) increase the precision of the analysis by exploiting the high-level semantics of events at higher levels of abstraction and (2) provide system-wide guarantees at the same time. For instance, using our model, we can soundly reason about the flow of a picture from the network through a browser into a cache file or a window on the screen by combining analyses at multiple layers.