Biblio

Third-party storage services pose the risk of integrity and confidentiality violations as the current storage policy enforcement mechanisms are spread across many layers in the system stack. To mitigate these security vulnerabilities, we present the design and implementation of Pesos, a Policy Enhanced Secure Object Store (Pesos) for untrusted third-party storage providers. Pesos allows clients to specify per-object security policies, concisely and separately from the storage stack, and enforces these policies by securely mediating the I/O in the persistence layer through a single unified enforcement layer. More broadly, Pesos exposes a rich set of storage policies ensuring the integrity, confidentiality, and access accounting for data storage through a declarative policy language. Pesos enforces these policies on untrusted commodity platforms by leveraging a combination of two trusted computing technologies: Intel SGX for trusted execution environment (TEE) and Kinetic Open Storage for trusted storage. We have implemented Pesos as a fully-functional storage system supporting many useful end-to-end storage features, and a range of effective performance optimizations. We evaluated Pesos using a range of micro-benchmarks, and real-world use cases. Our evaluation shows that Pesos incurs reasonable performance overheads for the enforcement of policies while keeping the trusted computing base (TCB) small.

Memory-safety violations are the primary cause of security and reliability issues in software systems written in unsafe languages. Given the limited adoption of decades-long research in software-based memory safety approaches, as an alternative, Intel released Memory Protection Extensions (MPX)–-a hardware-assisted technique to achieve memory safety. In this work, we perform an exhaustive study of Intel MPX architecture along three dimensions: (a) performance overheads, (b) security guarantees, and (c) usability issues. We present the first detailed root cause analysis of problems in the Intel MPX architecture through a cross-layer dissection of the entire system stack, involving the hardware, operating system, compilers, and applications. To put our findings into perspective, we also present an in-depth comparison of Intel MPX with three prominent types of software-based memory safety approaches. Lastly, based on our investigation, we propose directions for potential changes to the Intel MPX architecture to aid the design space exploration of future hardware extensions for memory safety. A complete version of this work appears in the 2018 proceedings of the ACM on Measurement and Analysis of Computing Systems.