SHF: Small: Auxiliary Hardware/Software Mechanisms for Flexible Memory Access Control

当今应用程序的可靠性、安全性和安全性依赖于执行过程中受控的数据访问和更新。例如，许多新兴应用程序由多个软件模块组成。为了在单个地址空间内保护这些模块彼此不受影响，需要仔细监视和控制模块间的操作。此外，在线系统的可靠性可以受益于对内存访问错误的实时检查，例如缓冲区溢出、内存泄漏和对未初始化数据的访问。类似地，内存访问监控可以支持复杂系统中的信息流跟踪以增强安全性。当今处理器中可用的机制与对虚拟内存的支持捆绑在一起，使得访问控制的实现既重量级又粗粒度。建议的研究将设计和利用新的轻量级内存访问控制机制，这些机制独立于现有的系统内存保护，并从属于现有的系统内存保护。在硬件级别，通过将访问控制机制放置在公共关键路径之外，该方法将对处理器核心的影响降至最低。在操作系统级别，所需的支持主要在内核内存管理函数之外，只有在执行时才会产生开销。这种辅助机制更易于实际部署，但它们能够支持细粒度和灵活的内存保护。结合这些硬件/软件机制，研究将设计出一种新的保护模型，该模型可以根据应用程序的要求在用户级或特权级进行操作。开发的灵活、高效的内存监控框架将启用调试工具，这些工具可以帮助检测内存访问错误，如越界访问，并帮助在实时系统中执行数据安全或隐私策略。拟议的工作将针对各种各样的应用和利用，以期验证提高程序员生产率的目标。

The reliability, safety, and security of today's applications depend on controlled data accesses and updates during execution. For instance, many emerging applications are composed of multiple software modules. To protect these modules from each other within a single address space, inter-module operations need to be carefully monitored and controlled. Additionally, the reliability of online systems can benefit from live checking of memory access errors such as buffer overflows, memory leaks, and accesses to uninitialized data. Similarly, memory access monitoring can support information flow mtracking in a complex system for enhanced security.Available mechanisms in today's processors are tied to support for virtual memory, making implementation of access control both heavy weight and coarse grained. The proposed research will design and utilize new light-weight memory access control mechanisms that are independent of and subordinate to existing system memory protection. At the hardware level, this approach minimizes impact on the processor core by placing the access control mechanisms outside the common critical path. At the operating system level, the required support is largely outside of the kernel memory management functions, incurring overhead only when exercised. Such auxiliary mechanisms are more amenable to practical deployment, yet they are capable of supporting fine-grained and flexible memory protection. In conjunction with these hardware/software mechanisms, the research will devise a new protection model that can be manipulated either at user or privileged level based on an application's requirements. The flexible, efficient memory monitoring framework developed will enable debugging tools that can help detect memory access errors such as out-of-bound accesses, and help enforce data security or privacy policies in live systems. The proposed work will target a wide variety of applications and utilizations with a view to validating the goal of improved programmer productivity.