SecureFS: A Secure File System for Intel SGX

Abstract

A trusted execution environment or a TEE facilitates the secure execution of an application on a remote untrusted server. In a TEE, the confidentiality, integrity, and freshness properties for the code and data hold throughout the execution. In a TEE setting, specifically Intel SGX, even the operating system (OS) is not trusted. This results in certain limitations of a secure application’s functionality, such as no access to the file system and network – as it requires OS support. Prior works have focused on alleviating this problem by allowing an application to access the file system securely. However, we show that they are susceptible to replay attacks, where replaying an old encrypted version of a file may remain undetected. Furthermore, they do not consider the impact of Intel SGX operations on the design of the file system. To this end, we present SecureFS, a secure, efficient, and scalable file system for Intel SGX that ensures confidentiality, integrity, and freshness of the data stored in it. SecureFS can work with unmodified binaries. SecureFS also considers the impact of Intel SGX to ensure optimal performance. We implement a prototype of SecureFS on a real Intel SGX machine. We incur a minimal overhead () over the current state-of-the-art techniques while adding freshness to the list of security guarantees.