Many security measures designed for large-scale compute hardware (e.g., workstations and servers) are not optimized for embedded systems. One such measure, Relocation Read-Only (RelRO), protects binary relocation sections from tampering after dynamic linking; however, RelRO depends on the presence of memory management hardware that not all embedded systems include. More generally, the latest hardware modifications to processor architectures may not always be available to provide security in small-scale embedded systems. In this paper, we propose another solution for relocation protection for use in embedded systems that have a field-programmable gate array (FPGA) on chip. Our solution prevents relocation section overwrites from diverting control flow as they would in an unprotected binary by implementing a hardware Root of Trust into which to store and out of which to retrieve shared library function pointers. We offer two system variations which provide designers with flexibility to choose a lighter or a more robust protection. We also demonstrate a proof of concept implemented on a popular FPGA development board and provide comparison with RelRO. Our work provides embedded system developers with a security measure like RelRO without requiring a customized memory management unit. Our work is useful on computer systems that include embedded reconfigurable logic on chip. The authors believe this is the first paper in which reconfigurable logic is used to provide security functionality previously implemented in a custom instruction set or other computer architecture modifications. Our work points toward a future where FPGA logic embedded on chip can be adapted to improve the security of software.

许多针对大型计算硬件（例如，工作站和服务器）设计的安全措施并未针对嵌入式系统进行优化。一种这样的措施，即只读重定位（RelRO），可防止二进制重定位节在动态链接后受到篡改。但是，RelRO取决于并非所有嵌入式系统都包含的内存管理硬件。更一般而言，对处理器体系结构的最新硬件修改可能并不总是可用于在小型嵌入式系统中提供安全性。在本文中，我们提出了另一种用于重定位保护的解决方案，用于在片上具有现场可编程门阵列（FPGA）的嵌入式系统中。我们的解决方案通过实现存储和从中获取共享库函数指针的硬件“信任之根”，防止重定位部分改写像在不受保护的二进制文件中那样转移控制流。我们提供两种系统变体，使设计人员可以灵活选择更轻或更坚固的保护装置。我们还将演示在流行的FPGA开发板上实现的概念验证，并提供与RelRO的比较。我们的工作为嵌入式系统开发人员提供了类似RelRO的安全措施，而无需定制的内存管理单元。我们的工作对包含嵌入式可重配置逻辑芯片的计算机系统很有用。作者认为这是第一篇使用可重配置逻辑来提供以前在自定义指令集或其他计算机体系结构修改中实现的安全功能的论文。我们的工作指向了一个未来，即可以修改嵌入式芯片上的FPGA逻辑以提高软件的安全性。