A Trusted Infrastructure for Symbolic Analysis of Event-Driven Web Applications

Abstract

We introduce a trusted infrastructure for the symbolic analysis of modern event-driven Web applications. This infrastructure consists of reference implementations of the DOM Core Level 1, DOM UI Events, JavaScript Promises and the JavaScript async/await APIs, all underpinned by a simple Core Event Semantics which is sufficiently expressive to describe the event models underlying these APIs. Our reference implementations are trustworthy in that three follow the appropriate standards line-by-line and all are thoroughly tested against the official test-suites, passing all the applicable tests. Using the Core Event Semantics and the reference implementations, we develop JaVerT.Click, a symbolic execution tool for JavaScript that, for the first time, supports reasoning about JavaScript programs that use multiple event-related APIs. We demonstrate the viability of JaVerT.Click by proving both the presence and absence of bugs in real-world JavaScript code.