Intel’s SGX architecture offers clients of public cloud computing platforms the ability to create hardware-protected enclaves whose contents are protected from privileged system software. However, SGX relies on system software for enclave memory management. In a sequence of recent papers, researchers have demonstrated that this reliance allows a malicious OS/hypervisor to snoop on the page addresses being accessed from within an enclave via various channels. This page address stream can then be used to infer secrets if the enclave’s page access pattern depends upon the secret and this constitutes an important class of side-channels. We propose SG XL , a hardware-software co-designed system that significantly increases the difficulty of any page address-based side-channels through the use of large pages. A large page maps address ranges at a much larger granularity than the default page size (at least 512× larger). SG XL thus significantly lowers resolution of the leaked page address stream and could practically throttle all flavors of page-address based side-channels. We detail the modifications needed to SGX’s software stack and the (minor) hardware enhancements required for SG XL to guarantee the use of large pages in the presence of adversarial system software. We empirically show that SG XL could be one of those rare systems that enhances security with the potential of improving performance as well.

中文翻译：

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SG XL

英特尔的 SGX 架构为公共云计算平台的客户提供了创建硬件保护的能力飞地其内容受到特权系统软件的保护。然而，SGX 依赖系统软件进行飞地内存管理。在最近的一系列论文中，研究人员已经证明，这种依赖允许恶意操作系统/管理程序通过各种渠道窥探从飞地内访问的页面地址。如果飞地的页面访问模式依赖于秘密并且这构成了重要的侧信道类别，则该页面地址流可以用于推断秘密。我们建议SG特大号，一个硬件-软件共同设计的系统，通过使用大页面显着增加了任何基于页面地址的侧通道的难度。大页面以比默认页面大小（至少大 512 倍）大得多的粒度映射地址范围。SG特大号因此显着降低了泄漏页面地址流的分辨率，并且实际上可以限制所有基于页面地址的侧通道。我们详细介绍了 SGX 软件堆栈所需的修改以及 SG 所需的（次要）硬件增强特大号保证在存在对抗系统软件的情况下使用大页面。我们凭经验表明，SG特大号可能是那些增强安全性并具有提高性能潜力的稀有系统之一。