Security, Scalability, and Future Trends: Pierre Lecomte on Zephyr RTOS
With the Elektor online conference, “Zephyr – The Open RTOS for Future Devices,” right around the corner in November, we spoke with speaker Pierre Lemcomte, Head of Software Solutions at embedded software developer Witekio, how Zephyr helps developers efficiently integrate, configure, and maintain security mechanisms – and why it is establishing itself as the platform for future-proof embedded development.
Elektor: What are currently the biggest challenges in terms of security issues in embedded and IoT systems?
Pierre Lecomte: One of the main challenges is keeping up with evolving connectivity needs and the growing threat of cyberattacks in the microcontroller world.
Hardware has evolved to enable us to address these challenges, notably with the arrival of the Cortex M23, M33, M55, and M85 chipsets, which include TrustZone support.
Software must keep pace by facilitating the implementation of these cybersecurity mechanisms in line with the growing capabilities of MCUs. Monitoring and maintenance have also become important. While in the past, we were happy with a functional version that we didn’t update, now it’s necessary to have the tools to track vulnerabilities and update our system as needed.
Elektor: What native security features does Zephyr RTOS offer, and how do they differ from other RTOS solutions?
Pierre Lecomte: Zephyr can be seen as an ecosystem rather than a simple RTOS that will facilitate the integration, configuration, and maintenance of cybersecurity mechanisms.
Previously, with other RTOSs, it was necessary to fully integrate cybersecurity mechanisms, perform configuration, and then maintain them. Zephyr addresses all these issues by offering integration, ensuring maintenance, and providing default mechanism configurations that meet cybersecurity requirements.
For example, this concerns the integration of secure boot with MCUboot, where a default key is already provided/used to sign and verify the firmware; this key is configurable in Kconfig. Mbed TLS integration is also facilitated, and TLS1.1 is disabled by default in the configuration.
Finally, unlike other RTOSs, Zephyr facilitates SBOM (Software Bill of Materials) generation to facilitate vulnerability tracking.
Elektor: How does Zephyr support the integration of hardware-based security features such as Trusted Execution Environments?
Pierre Lecomte: TF-M’s integration with generic APIs (PSA APIs) facilitates the use of hardware-based security features. Integrating TF-M into specific hardware and RTOS is not a simple task. Zephyr provides direct support for many boards on its dedicated TF-M GitHub repository.
However, Zephyr does not offer Secure Element support at the API or driver level.
Elektor: Can you explain how Zephyr isolates tasks and memory areas from each other to minimise attack surfaces?
Pierre Lecomte: Zephyr offers several mechanisms to isolate tasks and memory. The first is MPU activation per task/stack or software analysis of memory usage when the MPU is not present on the hardware. The second is using the MPU to define memory areas with write and read access rights. The last is the ability to create tasks in user mode.
Elektor: Is there a project or case study you would like to highlight when it comes to secure, production-ready solutions with Zephyr?
A case study can be Valmido with the objective of creating a cybersecurity-oriented product with connectivity, strong constraints requiring significant optimization. In a smart card format, it was necessary to integrate all the hardware with the battery, the screen, bluetooth connectivity and ensure a long battery life.
Zephyr helped by making it easier to integrate cybersecurity mechanisms, saving the team time.
Elektor: In your opinion, what are the most important trends and challenges for secure embedded development in the coming years – and what role will Zephyr play in this?
Pierre Lecomte: The evolution of cybersecurity mechanisms will be necessary to counter evolving cybersecurity threats. The Zephyr ecosystem is ideal for supporting developers through these changes, facilitating integration, configuration, and maintenance.
Also, updating connected products will be mandatory. Thanks to its native integration with solutions such as hawkbit, Memfault, Golioth, and Mender, Zephyr is the perfect companion.
Finally, vulnerability tracking is a complex subject, requiring both careful reporting of vulnerabilities in databases such as NVD and facilitating the generation of an SBOM. Zephyr is the most advanced RTOS in these areas.
Elektor: What advice would you give to developers who are just starting out with Zephyr RTOS and value security?
Pierre Lecomte: Zephyr is one of the most advanced ecosystem in microcontroller environment to manage cybersecurity. To get started easily on cybersecurity aspects with Zephyr, we recommend:
- Check if the hardware is well supported by Zephyr with TF-M support.
- Use TF-M and Zephyr ecosystem to create a POC with the cybersecurity mechanisms quickly.
- Check the available examples about the previously mentioned mechanisms.
For more information on Elektor’s online conference “Zephyr – The Open RTOS for Tomorrow’s Devices” on 5 November, see the conference website.
Editor’s note: eeNews Europe is an Elektor International Media publication.
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