Managing Encrypted Filesystems with dirlock

Summary

By Jake EdgeSeptember 29, 2025 OSS EU As with a mobile phone, a portable gaming device like the Steam Deck can contain lots of personal information that the owner would like to keep secret—especially given that such devices can do far more than gaming. Alberto Garcia worked with his colleagues at Igalia and people at Valve, the company behind the Steam gaming platform, to come up with a new tool to manage encrypted filesystems for SteamOS, which is a Linux distribution optimized for gaming. Garcia gave a talk about that tool, dirlock, at Open Source Summit Europe, which was held in Amsterdam in late August. In the talk, he looked at the design process for the encrypted-files feature, the alternatives considered, and why they made the choices they did. Over a long career at Igalia, he has worked on many different projects, including GNOME, the Maemo and MeeGo mobile-Linux platforms, and more recently on QEMU. He is also a Debian developer; "I've been using Debian basically all of my life, but I'm also contributing to the project and I've been an active developer for many years". At the moment, he is working on SteamOS. He was quick to point out that dirlock is not a new encryption system as it is only meant to manage filesystems that are encrypted using existing tools. Steam Decks and similar devices are easy to misplace—or steal. Since the hard drive is not encrypted, whoever ends up with the device can read its contents. That may not sound all that problematic for a gaming handheld, but the devices are much more than that; they may have credentials for things other than just Steam accounts, for one thing. In addition, the devices have a desktop mode where various programs can be installed, including web browsers that may store even more personal information. Users have been requesting disk encryption for a long time, Garcia said. From his slides, he showed the disk layout of the device. It is based around an A/B arrangement for the operating system partitions, whic...