Tue 20 Jun 2017 10:50 - 11:15 at Aula Master - Static Analysis and Security Chair(s): Mayur Naik

We describe a novel technique for proving $k$-safety properties (non-interference, determinism, etc.) via a decomposition that enables one to leverage non-relational reasoning techniques. The key is the inter-operation of the following principles. First, we observe that many $k$-safety properties of interest have a particular structure that we call $\psi$\emph{-quotient partitionability} where $\psi$ is a $k$-ary formula. Second, we develop a partitioning strategy of execution traces based on the $k$-safety property $\Phi$ of interest such that if $\psi$ holds for $k$ traces then they must be in the same partition. Finally, within a partition component $T_i$, we observe that we can prove $k$-safety by instead proving a universal property: all traces within the partition satisfy some common property $P_i$, chosen to be strong enough that it implies the $k$-safety property $\Phi$ of any $k$-tuple of traces in components $T_i$.

We apply this strategy to the task of discovering timing side channels. A key feature of our approach is a demand-driven partitioning strategy that uses high/low-annotated regex-like \emph{trails} to reason about one partition component of execution traces at a time. We have applied our technique in a prototype implementation tool called {\sc Blazer}, based on WALA, PPL, Z3, and the brics automaton library. We have proved non-interference of (or synthesized an attack specification for) 25 programs written in Java bytecode, including 7 classic examples from the literature, and 6 examples extracted from the DARPA STAC challenge problems.

Tue 20 Jun

 10:50 - 12:30: PLDI Research Papers - Static Analysis and Security at Aula Master Chair(s): Mayur Naik 10:50 - 11:15Talk Decomposition Instead of Self-Composition for Proving the Absence of Timing Channels Media Attached 11:15 - 11:40Talk Automatic Program Inversion using Symbolic Transducers Media Attached 11:40 - 12:05Talk Control-Flow Recovery from Partial Failure Reports Pre-print Media Attached 12:05 - 12:30Talk Rigorous Analysis of Software Countermeasures against Cache Attacks Media Attached