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It's based on a piece of technology called "ostree". Fetching updates means downloading new objects from a remote object store, setting up a hardlink farm in a
by Jasper_ 7y ago
It's based on a piece of technology called "ostree". Fetching updates means downloading new objects from a remote object store, setting up a hardlink farm in a special location in disk (somewhere like /ostree/deploy), and during early boot, it will switchroot into there. So you can have multiple "filesystem roots" (directories on the same rootfs) and the mechanism can set things up to atomically swap between them, without wasting much file space (anything shared between them is shared, since it's hardlinks).
The details can be found in the ostree documentation: https://ostree.readthedocs.io/en/latest/manual/atomic-upgrades/ https://ostree.readthedocs.io/en/latest/manual/atomic-upgrad...
- Jaruzel 7y agoWhat's to stop malware from modifying the hardlinks and injecting dodgy processes during the next reboot ?
- Jasper_ 7y agoThe immutability of the OS is not, alone, meant as an in-depth security measure. Don't run malware as root. If you want a fully trusted boot system, you'll have to use features like Secure Boot to verify that the BIOS and bootloader have not been tampered with. ostree supports signing commits and trees with GPG signatures, and like git, all objects are content-addressed by SHA256 hash, so it is possible to verify that the entire root tree and all objects within it have been signed by some trusted party.