SaTC: CORE: Small: Partition-Oblivious Real-Time Hierarchical Scheduling

随着现代计算和通信技术的进步，越来越多的趋势是将来自不同供应商的许多实时应用集成到单个更大的系统中，从而允许有效地利用公共硬件资源。在航空电子、汽车、工业控制系统等安全关键型系统中，在需要不同关键程度的应用程序之间提供强大的隔离是至关重要的，以便将故障操作限制在单个组件中。特别是，时间划分是安全组合实时应用程序的关键因素，其正确性高度依赖于它们的计时。实时分层调度通过抽象其他应用程序的不同行为，以及更重要的是，通过隔离其潜在的不当行为，促进了对单个实时应用程序的时间行为的模块化推理。然而，从安全的角度来看，传统的时间划分机制无法实现强时间隔离；执行定时的变化可能会被他人察觉，这使得在利用CPU时间方面彼此完全隔离的应用程序之间能够进行非法的信息流。该项目解决了在这样的集成软件环境中通过实时分层调度来实现信息流的问题。拟议的工作将使这些系统能够采用先进的硬件和软件技术，以安全的方式开发高端实时应用程序，极大地提高世界关键基础设施中许多关键组件的实用性和可靠性。该项目包括重要的课程开发活动和面向K-12学生以及女性和少数族裔学生的外联活动。该项目开发了一套算法解决方案，使实时分区忽略其他分区的不同时间行为-在所有分区之间实现基于非干扰的安全。主要的挑战是，这些机制应该独立于特定的调度算法，并且不会干扰底层的调度器。因此，该项目的重点是高度模块化和可扩展的机制，这些机制便于集成到各种现有系统中，而不需要完全重新设计操作系统。开发了调度分析技术，使系统设计者能够评估信息安全性的提高对CPU利用率的影响，以及在算法和实现级别上验证无干扰特性的形式化方法技术。这些解决方案在具有实际工作负载的原型实时系统上得到了验证。在教育方面，该项目将实时系统的新课程纳入现有课程，并为学生提供与现代实时应用程序实践体验的机会。它还旨在扩大未被充分代表的群体的参与，并为学生提供这一尖端领域的技术培训和经验的独特组合。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

With the advancement in modern computing and communication technologies, there is an increasing trend toward integrating many real-time applications from various vendors into a single, larger system, allowing an efficient utilization of common hardware resources. In safety-critical systems, such as avionics, automotive, industrial control systems, it is of utmost importance to provide strong isolation among the applications that require different levels of criticality in order to confine faulty operations to individual components. In particular, time partitioning is a key ingredient for a safe composition of real-time applications whose correctness highly depends on their timings. Real-time hierarchical scheduling facilitates modular reasoning about the temporal behavior of individual real-time applications by abstracting away varying behavior of other applications and, more importantly, by isolating their potential misbehavior. However, conventional time-partitioning mechanisms fail to achieve strong temporal isolation from a security viewpoint; variations in execution timings can be perceived by others, which enables illegitimate information-flow between applications that are completely isolated from each other in the utilization of CPU time. This project addresses the problem of information-flow through real-time hierarchical scheduling in such integrated software environment. The proposed work will allow such systems to employ advanced hardware and software technologies to develop high-end, real-time applications in a secure manner, dramatically improving the utility and reliability of many key components in the world’s critical infrastructure. The project includes significant curriculum development activities and outreach activities to K-12 students as well as women and minority students.This project develops a set of algorithmic solutions that make real-time partitions oblivious of others’ varying temporal behaviors -- achieving non-interference-based security among all partitions. The main challenge is that the mechanisms should be independent from particular scheduling algorithms and non-intrusive to the underlying schedulers. Hence, the project focuses on highly modular and extensible mechanisms that facilitate integration into a wide variety of existing systems without requiring complete reengineering of operating systems. Scheduling analysis techniques that can enable system designers to assess the impact of the improved information-security on the CPU utilization, as well as formal method techniques for the verification of the non-interference property in both algorithmic and implementation levels is developed. The solutions are validated on prototype real-time systems with real workload. On the education side, this project pushes new courses on real-time systems into the existing curriculum and also provides students opportunities for hands-on experience with modern real-time applications. It also aims to broaden the participation of underrepresented groups and give students a unique combination of technical training and experience in this cutting-edge field.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.