On Thu, 23 Jul 2020 at 12:09, Riccardo Paolo Bestetti via arch-general <arch-general@archlinux.org> wrote: > > I have root encryption set up on my system and I currently boot with the > sd-encrypt and sd-lvm hooks. > > I would like to change my current crypto setup in a way that would require > more step to unlock the root than just typing in a passphares. For this > reason, sd-encrypt clearly cannot serve my use case. > > For this reason, I would like to write a custom hook to mount the root > volume. Now, systemd boot doesn't have a concept of runtime hooks. Thus, I > need to make a systemd unit that gets pulled in by cryptsetup.target in the > place of systemd-cryptsetup@.service. (Basically, I need to replace the whole > systemd-cryptsetup-generator and systemd-cryptsetup logic.) > > However, I really have no idea on how to achieve this. Should I write a > custom mkinitcpio hook which completely bypasses sd-crypt/cryptsetup.target > and instead starts a different unit with my own decryption logic? Or is there > a way to hook into cryptsetup.target and instruct it to pull in my logic > instead of systemd-cryptsetup*? > > Of course, the other possibility is to just stop using a systemd boot and > instead setting up a busybox early userspace. Then it's just a matter of > writing a shell script. However, since I'm already using systemd for > everything - from the bootloader to userspace - I don't think it makes much > sense to do that. > > Any help/guidance/suggestion/criticism is highly appreciated. > > Riccardo Paolo Bestetti
haven't looked more deeply into it, but luks/dm-crypt/cryptsetup can use keys in the kernel keyring. So maybe it would be enough for you to have a service that configures the keyring before the cryptsetup service. https://fossies.org/linux/cryptsetup/docs/Keyring.txt -- damjan
