On-the-fly Inlining of Dynamic Security Monitors

Abstract

Abstract. Language-based information-flow security considers programs that manipulate pieces of data at different sensitivity levels. Securing information flow in such programs remains an open challenge. Recently, considerable progress has been made on understanding dynamic monitoring for secure information flow. This paper presents a framework for inlining dynamic information-flow monitors. A novel feature of our framework is the ability to perform inlining on the fly. We consider a source language that includes dynamic code evaluation of strings whose content might not be known until runtime. To secure this construct, our inlining is done on the fly, at the string evaluation time, and, just like conventional offline inlining, requires no modification of the hosting runtime environment. We present a formalization for a simple language to show that the inlined code is secure: it satisfies a noninterference property. We also discuss practical considerations and preliminary experimental results.

Dynamic vs. Static Flow-Sensitive Security Analysis

“…Magazinius et al [31] show how to perform informationflow monitor inlining on the fly: security checks are injected as the computation goes along. They consider a source language that includes dynamic code evaluation of strings whose content might not be known until runtime.…”

Value Sensitivity and Observable Abstract Values for Information Flow Control

“…Some perform static pre-analyzes, i.e., before the execution [13,21,25], or code inlining [12,6,23,29]. In other cases, the static analysis is triggered at runtime by the monitor [22,32,27,19].…”

“…There are several approaches to hybrid enforcement: inlining monitors [12,6,23,29], selective tracking [13,25], and the application of a static analysis at branch points [22,32,27,19]. Value sensitivity is particularly suitable for the latter to reduce the number of upgrades and increase precision (cf.…”

Architectures for Inlining Security Monitors in Web Applications

“…Magazinius et al [28] cope with dynamic code evaluation instructions by inlining on-the-fly. Dynamic code evaluation instructions are rewritten to make use of auxiliary functions that, when invoked at runtime, inject security checks into the available string.…”