Re: Question about decryption prompts

[Andrei Borzenkov]

On 01.04.2024 18:32, Sotir Danailov wrote:
> Hello, I have a question about how GRUB handles prompting for a
> password for encrypted disks using LVM. I am using Debian Testing and
> I have GRUB 2.12 installed, but this was present on GRUB 2.06 as well.
>
> So I have 2 encrypted logical volumes. One is for /boot and the other is for /
>
> I have keyfiles setup in the initramfs for these volumes so that the
> same prompts don't get shown after GRUB has handled them.
>
> When I boot, I get the first prompt for /boot, after which I get a
> second prompt for /, but the interesting thing about the second one is
> that if I just press enter without writing anything, it then shows me
> the menu to choose what I want to boot into. This doesn't happen with
> the first prompt for /boot.

The second prompt most likely comes from some code in grub.cfg and 
missing file is simply ignored. grub cannot ignore missing /boot as its 
own code is located there.

> I haven't setup keyfiles for GRUB, but
> according to the documentation, if I had, it shouldn't have shown a
> prompt in the first place.
>
> What I'm wondering is whether it reuses my input from the previous
> prompt. If I try to decrypt the disk manually using cryptsetup all
> prompts work properly and I always have to input the proper password
> to be able to unlock the device.