一种虚拟机系统中关于多级安全的强制访问控制框架Ⅰ：理论

At present, there are few security models which control the communication between virtual machines (VMs). Moreover, these models are not applicable to multi-level security (MLS). In order to implement mandatory access control (MAC) and MLS in virtual machine system, this paper designs Virt-BLP model, which is based on BLP model. For the distinction between virtual machine system and nonvirtualized system, we build elements and security axioms of Virt-BLP model by modifying those of BLP. Moreover, comparing with BLP, the number of state transition rules of Virt-BLP is reduced accordingly and some rules can only be enforced by trusted subject. As a result, Virt-BLP model supports MAC and partial discretionary access control (DAC), well satisfying the requirement of MLS in virtual machine system.As space is limited, the implementation of our MAC framework will be shown in a continuation.     

安全增强型虚拟化计算环境下的虚拟机动态迁移机制

As the number of Virtual Machines (VMs) consolidated on single physical server increases with the rapid advance of server hardware, virtual network turns complex and frangible. Modern Network Security Engines (NSE) are introduced to eradicate the intrusions occurring in the virtual network. In this paper, we point out the inadequacy of the present live migration implementation, which hinders itself from providing transparent VM relocation between hypervisors equipped with Network Security Engines (NSE H). This occurs because the current implementation ignores VM related Security Context (SC) required by NSEs embedded in NSE H. We present the CoM, a comprehensive live migration framework, for NSE H based virtualization computing environment. We built a prototype system on Xen hypervisors to evaluate our framework, and conduct experiments under various realistic application environments. The results demonstrate that our solution successfully fixes the inadequacy of the present live migration implementation, and the performance overhead is negligible.     

一种基于虚拟机的安全隔离与交换系统

文中分析了隔离网闸的原理以及应用中的问题,为实现更高效的安全隔离与数据交换系统,提出了基于一种基于虚拟机监控器体系结构的安全隔离与信息交互系统模型。并基于Xen虚拟机监控器系统,讨论了该模型的实现方式,利用Xen虚拟机体系结构实现不同客户域OS的安全隔离,采用Xen体系的超级调用、异步事件和域间内存共享访问机制,基于虚拟机管理器内部实现的访问控制模块（ACM）执行不同安全域信息受控交换策略,实现了不同客户域OS之间的受控数据交换。分析认为,该系统模型具有足够的安全隔离特性以及零内存拷贝的高效数据交换特性,具有重要的应用参考价值。     

Enhancing virtual environments with QoS aware resource management

Nowadays, the consolidation of application servers is the most common use for current virtualization solutions. Each application server takes the form of a virtual machine (VM) that can be hosted into one physical machine. In a default Xen implementation, the scheduler is configured to handle equally all of the VMs that run on a single machine. As a consequence, the scheduler shares equally all of the available physical CPU resources among the running VMs. However, when the applications that run in the VM dynamically change their resource requirements, a different solution is needed. Furthermore, if the resource usage is associated with service-level agreements, a predefined equal share of the processor power is insufficient for the VMs. Within the Xen’s primitives, even though it is possible to tune the scheduler parameters, there is no tool to achieve the dynamic change of the share of the processor power assigned to each VM. A combination of a number of primitives, however, appears to be suited as a base for achieving this. In this paper, we present an approach to efficiently manage the quality of service (QoS) of virtualized resources in multicore machines. We evaluate different alternatives within Xen for building an enhanced management of virtual CPU resources. We compare these alternatives in terms of performance, flexibility, and ease of use. We devise an architecture to build a high-level service that combines interdomain communication mechanisms with monitoring and control primitives for local resource management. We achieve this by our solution, a local resource manager (LRM), which adjusts the resources needed by each VM according to an agreed QoS. The LRM has been implemented as a prototype and deployed on Xen-virtualized machines. By means of experiments, we show that the implemented management component can meet the service-level objectives even under dynamic conditions by adapting the resources assigned to the virtualized machines according to demand. With the LRM, we therefore achieve both fine-grain resource allocation and efficient assignment.     

基于Intel VT-d技术的虚拟机安全隔离研究

资源隔离是计算机安全的一个重要手段,良好的安全隔离使得虚拟机技术成为近年来学术界和工业界的热点。在深入分析Linux环境下Xen完全虚拟化技术理论的基础上,设计了一个基于IntelVT技术的虚拟机安全隔离设计方案。该方案通过安全内存管理（SMM）和安全I/O管理（SIOM）两种手段进行保护,完善了Xen宿主机系统与虚拟机系统之间的安全隔离,为Xen虚拟机在实际的安全隔离环境中的应用提供了较高的安全保障。     

基于密码的云计算虚拟化网络安全研究

虚拟化网络技术是构建新一代的云计算数据中心,为云计算环境提供基础设施支撑的关键。在研究云计算数据中心典型架构与访问应用模式的基础上,从用户安全接入、通信隔离与机密性保护等方面分析了数据中心虚拟化网络的安全需求,提出了虚拟化网络安全技术框架,重点针对基于密码技术强化虚拟化网络安全,保障虚拟机之间的通信保护、信息隔离与安全交换等安全机制进行了分析与设计,提出了一种可供参考的解决方案。     

Dynamic Resource Allocation and Scheduling for Cloud‐Based Virtual Content Delivery Networks

This paper proposes a novel framework for virtual content delivery networks (CDNs) based on cloud computing. The proposed framework aims to provide multimedia content delivery services customized for content providers by sharing virtual machines (VMs) in the Infrastructure‐as‐a‐Service cloud, while fulfilling the service level agreement. Furthermore, it supports elastic virtual CDN services, which enables the capabilities of VMs to be scaled to encompass the dynamically changing resource demand of the aggregated virtual CDN services. For this, we provide the system architecture and relevant operations for the virtual CDNs and evaluate the performance based on a simulation.     

面向无线传感器网络的混沌加密与消息鉴别算法

针对数字混沌密码无法直接在轻量的传感节点上实现,介绍了一种基于整数型混沌映射的轻量级分组加密算法,并提出一种新型的消息鉴别码方案,具有输出长度可变、混沌序列复合安全等特点,最后实现了一个完整的无线传感网数据安全传输应用方案,并在Mica2节点上给出性能分析。实验表明该方案对无线传感网具有更高的实用性。     

Measuring performance degradation of virtual machines based on the Bayesian network with hidden variables

In the virtualized environment, multiple virtual machines (VMs) sharing the same physical host are vulnerable to resource competition, which may cause performance interference among VMs and thus lead to VM performance degradation. This paper focuses on measuring CPU, memory, I/O, and the overall VM performance degradation caused by the performance interference according to the properties in the runtime environment of VMs. To this end, we adopt Bayesian network (BN), as the framework for uncertainty representation and inference, and construct a VM property‐performance BN (VPBN) with hidden variables, which represent the unobserved performance degradation of CPU, memory, and I/O, respectively. Then, we present the method to measure performance degradation of VMs by probabilistic inferences with the VPBN. Experimental results show the accuracy and efficiency of our method.     

Symbiotic Dynamic Memory Balancing for Virtual Machines in Smart TV Systems

Smart TV is expected to bring cloud services based on virtualization technologies to the home environment with hardware and software support. Although most physical resources can be shared among virtual machines (VMs) using a time sharing approach, allocating the proper amount of memory to VMs is still challenging. In this paper, we propose a novel mechanism to dynamically balance the memory allocation among VMs in virtualized Smart TV systems. In contrast to previous studies, where a virtual machine monitor (VMM) is solely responsible for estimating the working set size, our mechanism is symbiotic. Each VM periodically reports its memory usage pattern to the VMM. The VMM then predicts the future memory demand of each VM and rebalances the memory allocation among the VMs when necessary. Experimental results show that our mechanism improves performance by up to 18.28 times and reduces expensive memory swapping by up to 99.73% with negligible overheads (0.05% on average).