SGXIO: Generic Trusted I/O Path for Intel SGX

TL;DR

SGXIO introduces a trusted path architecture for Intel SGX that enables secure user I/O and application protection against malicious operating systems, combining hardware enclaves with hypervisor-based trusted paths for broad usability.

Contribution

It presents a novel architecture that provides generic trusted I/O paths for SGX, enhancing security for user applications on untrusted OSes and enabling secure local and cloud applications.

Findings

Supports trusted I/O paths for SGX enclaves

Works with unmodified operating systems on commodity hardware

Can convert debug enclaves into secure production enclaves

Abstract

Application security traditionally strongly relies upon security of the underlying operating system. However, operating systems often fall victim to software attacks, compromising security of applications as well. To overcome this dependency, Intel introduced SGX, which allows to protect application code against a subverted or malicious OS by running it in a hardware-protected enclave. However, SGX lacks support for generic trusted I/O paths to protect user input and output between enclaves and I/O devices. This work presents SGXIO, a generic trusted path architecture for SGX, allowing user applications to run securely on top of an untrusted OS, while at the same time supporting trusted paths to generic I/O devices. To achieve this, SGXIO combines the benefits of SGX's easy programming model with traditional hypervisor-based trusted path architectures. Moreover, SGXIO can tweak insecure debug enclaves to behave like secure production enclaves. SGXIO surpasses traditional use cases in cloud computing and makes SGX technology usable for protecting user-centric, local applications against kernel-level keyloggers and likewise. It is compatible to unmodified operating systems and works on a modern commodity notebook out of the box. Hence, SGXIO is particularly promising for the broad x86 community to which SGX is readily available.