On Fri, 28 Aug 2020 15:28:41 +0000 HardenedArray via Grub-devel <grub-devel@gnu.org> wrote:
> I run Arch Linux as an encrypted /, /boot and swap system. That > encrypted /boot is nothing more than a folder under /, however two > Keyslots are required to boot. > > If I understand the boot process correctly, LUKS Keyslot 1 is used by > grub to unlock /boot, then control is handed off to the kernel which > uses Keyslot 0 to unlock /. My passphrase, entered once, unlocks both. This is confusing. Do you have a two LUKS devices, one for / and one for /boot? If so, you only need to access LUKS Keyslot 0 on either device. > Grub can easily unlock /boot, assuming / is originally encrypted as a > `type= luks1` partition. It seems, however, it is not possible for > grub to unlock this same /boot if / is converted to `--type= luks2`. > > Is my assumption correct, and if so, what is preventing grub from > this `type= luks2` /boot unlocking? Please post the output of `cryptsetup luksDump --debug-json <luks device>' (for both /boot and / if using two LUKS devices). > I am running: grub-git 2.04.rc1.r19.g4e7b5bb3b-1 from the Arch (AUR). > This package was last updated on 7 Feb 2020. See: > https://aur.archlinux.org/packages/grub-git/ > > I originally encrypted the partition with: `cryptsetup -c > aes-xts-plain64 -h sha512 -s 512 --use-random --type luks1 luksFormat > /dev/sdXZ` > > Then I set up two LVs: swap (512M) and / (remaining partition space). > That swap LV is assigned as `dm-1` and / is assigned as `dm-2`. dm-2 > runs BTRFS, if that matters. Grub boots that system without issue. > > The process I used to test LUKS2 encrypted /boot support: > > 1. UEFI boot from any reasonably recent arch iso, and run: > `cryptsetup convert --type luks2 /dev/sdXZ`. That command will > succeed, and luksDump will show PBKDF: pbkdf2 for both Keyslot 0 and > 1. > > 2. Run cryptsetup open /dev/sdXY <something> > > 3. Mount everything and arch-chroot into / > > 4. Run `mkinitcpio -P linux` > > 5. Run `grub-install --target=x86_64-efi --efi-directory=/efi > --modules="luks2 part_gpt cryptodisk" --bootloader-id=<some-id>`. Is /efi on the encrypted /boot partition? If so how are you going to get the BIOS to boot it? > Note: If `--modules="luks2 part_gpt cryptodisk" ` is not appended to > grub-install, then the `ls` results in step 9 (below) only lists > (proc) and (hd0) - and/or cryptodisk: command not found. > > 6. Run grub-mkconfig -o /boot/grub/grub.cfg > > 7. Exit, umount and reboot. > > 8. Immediately following power on: you are greeted by the dreaded: > error: disk 'lvmid/some-lengthy-UUID' not found. Entering rescue > mode. That lengthy UUID is exact UUID of my `dm-2` which is my > encrypted / LV. > > 9. At the `grub rescue>` prompt: type `ls`. There I see (proc) (hd0) > and (hd0,gpt1)...(hd0,gpt7) where gpt7 is my last partition and where > my encrypted / resides. > > 10. Still at `grub rescue>` type: `cryptomount (hd0,gpt7)` which then > requires my passphrase. After correct passphrase entry, and hitting > Enter only returns: > > `error: Could not parse digest 1.` > > Incredibly, if you repeat step 10 and intentionally enter an > incorrect passphrase, you get the same: > > `error: Could not parse digest 1.` > > In fact, if you enter NO passphrase and hit Enter, you also get: > > `error: Could not parse digest 1.` It looks like you're hitting the bug in master which is triggered by attempting to cryptomount a LUKS device using a keyslot that is not the first one. Could you post the output of `cryptsetup luksDump --debug-json <luks device>'? That bug is fixed by the patch on this mailing list with title "[PATCH v2 3/9] luks2: Fix use of incorrect index and some error messages". > Very frustrating indeed! > > Does anyone know why grub is failing this way, and does a workaround > exist? > > Thank you for your time...suggestions welcome. Glenn _______________________________________________ Grub-devel mailing list Grub-devel@gnu.org https://lists.gnu.org/mailman/listinfo/grub-devel
