Information Flow Tracking for Side-Effectful Libraries

Paper in proceeding, 2018

Dynamic information flow control is a promising technique for ensuring
confidentiality and integrity of applications that manipulate sensitive
information. While much progress has been made on increasingly powerful
programming languages ranging from low-level machine languages to high-level
languages for distributed systems, surprisingly little attention has been
devoted to libraries and APIs. The state of the art is largely an
all-or-nothing choice: either a shallow or deep library
modeling approach. Seeking to break out of this restrictive choice, we
formalize a general mechanism that tracks information flow for a language
that includes higher-order functions, structured data types and references.
A key feature of our approach is the model heap, a part of the
memory, where security information is kept to enable the interaction between
the labeled program and the unlabeled library. We provide a
proof-of-concept implementation and report on experiments with a file system
library. The system has been proved correct using Coq.