Hardware support for trusted execution in modern CPUs enables tenants to shield their data processing workloads in otherwise untrusted cloud environments. Runtime systems for the trusted execution must rely on an interface to the untrusted host OS to use external resources such as storage, network, and other functions. Attackers may exploit this interface to leak data or corrupt the computation. We describe SGX-LKL, a system for running Linux binaries inside of Intel SGX enclaves that only exposes a minimal, protected and oblivious host interface: the interface is (i) minimal because SGX-LKL uses a complete library OS inside the enclave, including file system and network stacks, which requires a host interface with only 7 calls; (ii) protected because SGX-LKL transparently encrypts and integrity-protects all data passed via low-level I/O operations; and (iii) oblivious because SGX-LKL performs host operations independently of the application workload. For oblivious disk I/O, SGX-LKL uses an encrypted ext4 file system with shuffled disk blocks. We show that SGX-LKL protects TensorFlow training with a 21% overhead.

中文翻译：

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SGX-LKL：保护主机操作系统接口以实现可信执行

现代 CPU 中可信执行的硬件支持使租户能够在其他不受信任的云环境中保护他们的数据处理工作负载。可信执行的运行时系统必须依赖与不可信主机操作系统的接口来使用外部资源，例如存储、网络和其他功能。攻击者可能会利用此接口泄漏数据或破坏计算。我们描述了 SGX-LKL，这是一个在英特尔 SGX 飞地内运行 Linux 二进制文件的系统，它只公开一个最小的、受保护的和不经意的主机接口：接口是 (i) 最小的，因为 SGX-LKL 在飞地内使用一个完整的库操作系统，包括文件系统和网络堆栈，只需要一个只有 7 个调用的主机接口；(ii) 受到保护，因为 SGX-LKL 透明地加密和完整性保护所有通过低级 I/O 操作传递的数据；(iii) 因为 SGX-LKL 执行独立于应用程序工作负载的主机操作，所以没有注意到。对于不经意的磁盘 I/O，SGX-LKL 使用带有混洗磁盘块的加密 ext4 文件系统。我们展示了 SGX-LKL 以 21% 的开销保护 TensorFlow 训练。