MicroStache: A Lightweight Execution Context for In-Process Safe Region Isolation

In this work we present, MicroStache, a specialized hardware mechanism and new process abstraction for accelerating safe region security solutions. In the safe region paradigm, an application is split into safe and unsafe parts. Unfortunately, frequent mixing of safe and unsafe operations stresses memory isolation mechanisms. MicroStache addresses this challenge by adding an orthogonal execution domain into the process abstraction, consisting of a memory segment and minimal instruction set. Unlike alternative hardware, MicroStache implements a simple microarchitectural memory segmentation scheme while integrating it with paging, and also extends the safe region abstraction to isolate data in the processor cache, allowing it to protect against cache side channel attacks. A prototype is presented that demonstrates how to automatically leverage MicroStache to enforce security polices, SafeStack and CPI, with 5% and 1.2% overhead beyond randomized isolation. Despite specialization, MicroStache enhances a growing and critical programming paradigm with minimal hardware complexity.