On Tue, Oct 14, 2025, at 4:52 AM, Lennart Poettering wrote: > On Di, 14.10.25 00:49, Chris Murphy ([email protected]) wrote: >> There is a patch to use the Btrfs bootloader pad for grubenv, >> it's only 1 KiB. And then GRUB and read and write to it there. > > BTW, for btrfs the first 64K of the disk are entirely unused, it would > be trivial for grub to put its data there without asking anyone for > cooperation. The first copy of the btrfs superblock is at offset 64K.
**There is a patch** to do exactly this. > Still a really really bad idea though, but just pointing that > out. Bypassing or even corrupting an fs when doing updates to a disk, > is a terrible idea. I'm not sure it was ever allowed on Btrfs. But I'm not finding any patches about it. >> It's not correct nothing is gained by a different fs. Aside from >> pooling, (open)SUSE has leveraged Btrfs for bootable snapshots. Can >> Fedora do this some other way? Yes, it'd be more work, rather than >> leveraging what Btrfs is designed to do. GRUB follows snapshots just >> fine, and has for a very long time. > > Whenever you do something like this it implies you are not interested > in a proper, modern authentication/encryption boot chain, because if > you do that you basically have to turn your boot loader into something > that speaks verity, does tpm2 measurements and policy enforcement, > that does fido2, and pkcs#11. And frankly, that's just not realistic > to reimplement in a boot loader. Apple and Microsoft have implemented all of what you say is unrealistic, except verity, into their bootloaders. Literally how all of iOS boots, not even the bootloader is exposed on a simple system. And on desktop and server Windows, only the bootloader is exposed as plaintext, everything else is on Bitlocker encrypted NTFS. Are you saying only AOSP is using a modern boot chain? Is anyone else using verity? You want Fedora to mimic mobile device booting? That's a pretty significant change. -- Chris Murphy -- _______________________________________________ devel mailing list -- [email protected] To unsubscribe send an email to [email protected] Fedora Code of Conduct: https://docs.fedoraproject.org/en-US/project/code-of-conduct/ List Guidelines: https://fedoraproject.org/wiki/Mailing_list_guidelines List Archives: https://lists.fedoraproject.org/archives/list/[email protected] Do not reply to spam, report it: https://pagure.io/fedora-infrastructure/new_issue
