新型非易失存储的安全与隐私问题研究综述

A Survey on Security and Privacy of Emerging Non-Volatile Memory

近年来,以相变存储器(phase change memory,PCM)为代表的各种新型非易失存储(nonvolatile memory,NVM)技术得到广泛关注.NVM同时具有传统内存的字节寻址特性和外存的非易失特性,因而可以同时替代内存和外存,也可以用于混合存储体系结构.NVM具有低延时、高密度、低功耗的优势,有效缓解了存储墙问题.然而,由于应用程序可以直接通过存取指令(load/store)接口访问NVM,并且掉电后存储在NVM上的信息不会丢失,这给NVM的应用带来了一些新的安全和隐私挑战.首先讨论了持久化内存泄漏、不经意写操作、元数据安全、恶意磨损攻击、非易失指针等NVM应用中可能存在的安全问题以及最新的解决方案;然后讨论了数据保护、信息泄露等NVM应用中可能存在的隐私问题及现有的解决方案;最后探讨了NVM还需解决的安全和隐私问题,包括非易失缓存、程序安全等,并提出了一些解决方案,包括权限和保护机制的融合、使用易失性的NVM等.

In recent years, emerging non-volatile memory （NVM） technologies, such as phase change memory （PCM）, spin-transfer torque RAM （STT-RAM）, and memristor have gained great attention of researchers. NVM has both byte-addressable and non-volatile features, thereby making it possible to replace both traditional main memory and persistent storage. Also, NVM can be used in hybrid memory and storage architecture. Due to the advantages of low latency, high density, and low power, NVM has become the promising memory technology because of the effect of alleviating memory wall problem. However, applications can access NVM directly through ordinary load/store interface, and more important, data resided in the NVM still retains after power loss, thus it imposes new challenges of security and privacy. This paper surveys several security problems about NVM and existing solutions including persistent memory leak, stray writes, metadata security, malicious wearout attacks, and non-volatile pointer. Then, privacy issues and existing studies about NVM, such as data protection and information leaks, are discussed. Finally, we explore other potential security and privacy issues related to NVM and propose several possible solutions, such as convergence of permission and protection, security of non-volatile cache, volatile NVM, and program security.