基于轻量虚拟化可信基的可信计算环境构建机制研究

Combination of virtualization technology and trusted hardware platform provides an effective way to solve the challenges of computer security. However, as virtualization is originally motivated and designed for consolidating servers and planning resources, these approaches usually introduce heavy performance overhead caused by virtual machine monitors (VMMs or hypervisors), which manage resource isolation and schedule tasks between VMs. Therefore, even if a user does not need high security environment for every application or for all the execution time a sensitive application, he has to bear the cost and performance overhead of virtualization. Furthermore, the concern of the trustworthiness for general purpose VMMs arises as they have grown both in code size and functional features, which make them like a traditional OS with large TCB. Consequently, similar to commodity OS,VMMs are prone to design and implement vulnerabilities, and therefore their isolation and security functions might be compromised by attacks from guest OS. .To solve these problems, this project focuse on the following aspects: 1) how to created and removed the lightweight virtualization layer dynamically during the operating system runtime, and therefore the system does not need to bear the overhead of virtualization when it does not run any high-security applications;2)how to build dynamic chain of trust and provide protection for the lightweight virtual machine monitor(LVMM) in untrusted environments ; 3) how to monitor the software behavior by the lightweight virtual machine monitor: 4) how to provide fine-grained process memory isolation and trusted system service by the LVMM.

诸如航空、航天、金融、证券、医疗、电子政务等关键领域，对软件的可信性提出了迫切需求。虚拟机架构能够实现系统资源的虚拟化并可以隔离软件与硬件、应用软件与底层系统之间的直接依赖关系。通过虚拟化技术与可信硬件平台相结合的方式构建可信计算环境，为解决计算机安全面临的挑战提供了有效的途径。然而,基于虚拟化技术构建可信计算环境还面临着虚拟化开销大、信任链构建、隔离粒度及不可信服务调用等诸多挑战。针对这些问题，本课题拟从4个方面开展研究：1）轻量虚拟化可信基的构建机制：研究解决轻量虚拟化可信基的动态拆装和自适应问题；2）基于轻量虚拟化可信基的动态可信架构：研究解决基于轻量虚拟化可信基的动态信任链构建、完整性保护等问题；3）基于轻量虚拟化可信基的软件行为监控机制：研究解决基于轻量级虚拟化可信基的软件行为监控问题；4）基于轻量级虚拟化的软件可信执行机制，研究解决软件执行过程中的内存隔离、可信服务调用等问题。

随着信息技术的发展，现代社会对计算系统的依赖性越来越大。诸如：航空、航天、金融、证券、交通、医疗、电子商务等应用领域，对系统提供可信计算环境的需求越来越迫切。通过软件和可信硬件平台相结合的方式构建可信计算环境，为解决计算机安全面临的挑战提供了新的途径。基于虚拟机架构构建可信计算环境，能为上层应用提供强有力的安全保证。现有的方法依据其提供的隔离粒度可分为两类：一类为高安全要求的程序提供一个单独的隔离虚拟域；另一类则为高安全需求的程序提供在原操作系统内的隔离运行区域。然而，这些基于虚拟化技术构建的可信计算环境，还面临以下1）可信基构建问题2）信任链构建问题3）隔离粒度和不可信服务的问题。.针对上述问题，本课题“基于轻量虚拟化可信基的可信计算环境构建机制研究”从如下4个方面展开：（1）轻量虚拟化可信基的构建机制（2）基于轻量虚拟化可信基的动态可信架构（3）基于轻量虚拟化可信基的软件行为监控机制（4）基于轻量虚拟化可信基的软件可信执行机制。形成了如下成果：1）基于实体依赖关系的信任链模型。2）在不同应用场景下（安全输入、沙盒以及可信网络）给出轻量虚拟化可信基剪裁，基于轻量虚拟化可信基础的软件行为可信架构，监控机制，执行机制等问题，实现软件的可信执行等方案。3) Android架构下应用相似性的检测研究。.本课题研究形成的理论和技术将为计算系统提供可信保障，极大地提升现有计算平台的安全性，推动虚拟化技术在构建可信计算环境方面的商业化应用。