Rouven: Practical Application of Verified Boot

More and more applications of embedded linux systems require them to ensure that only trusted software is started on the device. This means that verified boot procedures need to be employed to verify the software running on the device. This talk will highlight the necessary components to cryptographically verify the bootloader, kernel and filesystem. It will also show how these components can be integrated using the OpenEmbedded build system. Bootloader verification will be covered by providing examples to use the signing.bbclass in Yocto in conjunction with the NXP CST tool to sign a bootloader, kernel verification is covered by a to be upstreamed fitimage class and filesystem verification will be shown with a dm-verity class example for Yocto. Additionally the talk will highlight common pitfalls when deploying locked down embedded systems encountered during project work. We will also cover the case of using GPLv3 licenses on locked down devices.

Rouven and Jan: BoF: Automated Testing & Board Farming

In face of the strict requirements of the CRA legislation on the horizon for EU markets, one of the key techniques to rapidly test new software releases is an automated testing setup. This session wants to collect the current state of the automated testing landscape and discuss current development directions, tools and projects. We will provide a quick summary of current projects in the space and than have a quick vote on which topics to discuss. Thereafter we encourage discussion between the audience members.

Ahmad: Taming DMA: Tales Wrestling Memory Corruption

Direct Memory Access frees up the CPU for other important work, while devices read and write data in the background. This is as good as it sounds and most embedded systems make ample use of this; for good sound and otherwise. On the flip side, incorrectly configured DMA and the creeping memory corruption that results can decidedly be more unpleasant than the possible slow-down of using PIO.

Ahmad's bootloader and kernel escapades have not been spared from the wrath of DMA masters. In this talk, he will share tales of his debugging campaigns and how tracking down memory corruption led him to learn, one bug at a time, more about the internals of Linux' and barebox' DMA API, ARM cache maintenance and the limitations of DMA controllers.