一句话：提出“树中树”AMNT，以低片上面积实现崩溃一致的安全 SCM 完整性元数据。
安全内存可防止内存破坏攻击，但非易失存储级内存（SCM）给完整性校验带来新挑战。Bonsai Merkle Tree（BMT）等元数据缓存在易失片上缓存中，掉电可能丢失，因此需保证元数据更新持久化到 SCM。现有惰性更新崩溃一致方案优化了更新开销，却常忽视片上面积，导致稀缺片上空间利用低效。本文提出 A Midsummer Night's Tree（AMNT），一种“树中树”方法，为 SCM 提供崩溃一致的完整性保护。它将潜在硬件复杂度转移到软件，以低运行时开销限制安全元数据占用的片上面积。评估表明，面向内存存储应用，AMNT 相比最先进方案平均减少 41% 执行开销，同时显著降低协议所需片上面积。
Secure memory is a highly desirable property to prevent memory corruption-based attacks. The emergence of nonvolatile, storage class memory (SCM) devices presents new challenges for secure memory. Metadata for integrity verification, organized in a Bonsai Merkle Tree (BMT), is cached on-chip in volatile caches, and may be lost on a power failure. As a consequence, care is required to ensure that metadata updates are always propagated into SCM. To optimize metadata updates, state-of-the-art approaches propose lazy update crash consistent metadata schemes. However, few consider the implications of their optimizations on on-chip area, which leads to inefficient utilization of scarce on-chip space. In this paper, we propose A Midsummer Night's Tree (AMNT), a novel "tree within a tree" approach to provide crash consistent integrity with low run-time overhead while limiting on-chip area for security metadata. Our approach offloads the potential hardware complexity of our technique to software to keep area overheads low. Our proposed mechanism results in significant improvements (a 41% reduction in execution overhead on average versus the state-of-the-art) for in-memory storage applications while significantly reducing the required on-chip area to implement our protocol.
@inproceedings{ThomasWMILB24,
title = {A Midsummer Night’s Tree: Efficient and High Performance Secure SCM},
author = {Samuel Thomas and Kidus Workneh and Jac McCarty and Joseph Izraelevitz and Tamara Lehman and R. Iris Bahar},
booktitle = {ASPLOS},
year = {2024},
doi = {10.1145/3620666.3651354}
}