Year: 2016
Type: conference-paper
Abstract: Protecting the confidentiality of information manipulated by a computing system is one of the most important challenges facing today's cybersecurity community. A promising step toward conquering this challenge is to formally verify that the end-to-end behavior of the computing system really satisfies various information-flow policies. Unfortunately, because today's system software still consists of both C and assembly programs, the end-to-end verification necessarily requires that we not only prove the security properties of individual components, but also carefully preserve these properties through compilation and cross-language linking. In this paper, we present a novel methodology for formally verifying end-to-end security of a software system that consists of both C and assembly programs. We introduce a general definition of observation function that unifies the concepts of policy specification, state indistinguishability, and whole-execution behaviors. We show how to use different observation functions for different levels of abstraction, and how to link different security proofs across abstraction levels using a special kind of simulation that is guaranteed to preserve state indistinguishability. To demonstrate the effectiveness of our new methodology, we have successfully constructed an end-to-end security proof, fully formalized in the Coq proof assistant, of a nontrivial operating system kernel (running on an extended CompCert x86 assembly machine model). Some parts of the kernel are written in C and some are written in assembly; we verify all of the code, regardless of language.
Authors: David Costanzo, Zhong Shao, Ronghui Gu
Institution: Yale University
Language: English
Subfield: Hardware and Architecture
Field: Computer Science
Domain: Physical Sciences
Open Access status: bronze
Awards: G1889560887, G4577670171, G4713059963, G5626127761, Collaborative Research: Expeditions in Computing: The Science of Deep Specification, G7515674563, SHF: Small: VeriQ: Formal Quantitative Software Verification in Realistic Application Scenarios, G789317362, G8542633891, TC: Medium: Making OS Kernels Crash-Proof by Design and Certification
OpenAlex ID: W2415236938