Type-Directed, Secure-by-Construction Enclave Partitioning for LLVM

2026-09-01

AI Summary

该研究通过构建一种新的类型系统SIR及其扩展SIREN，结合自动编译技术，解决了在LLVM低级语言中使用TEE时的信息流安全问题及手动分区难题。

Abstract

Trusted Execution Environments (TEEs) provide hardware-supported isolation through enclaves that protect code and data independently of software abstractions. However, TEEs alone cannot enforce information-flow security. This problem is further aggravated in LLVM-like low-level languages that allow unrestricted pointer manipulation and unstructured control flow. Moreover, using TEEs effectively typically requires manually partitioning applications into enclave and non-enclave components, a process that is labor-intensive, error-prone, and lacks fine-grained control. We address these challenges with a three-step approach. First, we formalize SIR, an enclave-oblivious calculus based on LLVM IR, equipped with a novel permissive type system that enforces security against low-level attackers. To obtain meaningful guarantees, SIR combines information-flow control with security-aware coarse-grained memory safety. Second, we extend SIR to SIREN, an enclave-aware calculus that enforces noninterference against stronger attackers capable of observing arbitrary non-enclave memory. Third, we develop a type-driven, type-preserving compilation from SIR to SIREN that automatically produces secure enclave-aware programs, eliminating manual partitioning while providing fine-grained control over host-enclave boundaries. We implement and evaluate SPLITR on thirteen microbenchmarks and real-world workloads, including applications from SGXGauge, on Intel SGX hardware. SPLITR scales to OpenSSL (425,953 LLVM IR instructions) and supports multiple objectives that expose trade-offs among enclave TCB size, host-enclave transitions, and boundary data movement. For OpenSSL, optimizing for transitions reduces them from 393 to 187. Runtime overhead is dominated by fixed enclave costs for short-running workloads, whereas long-running applications better amortize these costs and approach native performance.

Problem

• Trusted Execution Environments
• information-flow security
• LLVM

Innovation

• Type-Directed Partitioning
• Secure-by-Construction
• Information-Flow Security
• Automated Enclave Generation
• Fine-Grained Control