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#1 2019-01-05 00:30:43

f1she3
Member
Registered: 2019-01-05
Posts: 6

[SOLVED] LUKS + UEFI - grub asking passphrase twice

Hello !

I have a dual boot installation, a windows one and a Linux one using windows' efi partition and grub :
     |--- /dev/sda2 : efi partition
HDD---
     |--- /dev/sda3 : windows partition

SSD--- /dev/sdb1 : luks encrypted partition


I have read the several wiki pages to encrypt my root partition, and after many tries it almost works, but I have to enter the passphrase twice : once before the grub menu appears (the unexpected one : https://imgur.com/9mBq9iU), and a second time when i choose to boot on linux, wich is the expected behaviour.
I had to set

GRUB_ENABLE_CRYPTODISK=y

in /etc/default/grub because

grub-install --target=x86_64-efi --efi-directory=/boot/esp --bootloader-id=GRUB

gave me the following error :

grub-install: error: attempt to install to encrypted disk without cryptodisk enabled. Set `GRUB_ENABLE_CRYPTODISK=y' in file `/etc/default/grub'.

I think I shouldn't need this parameter which is required only for encrypted /boot, is that right ?

So do you know guys how I can fix it and where the problem is ?

Thanks !

PS : Grub takes also much longer than usual to load

Last edited by f1she3 (2019-01-13 21:19:45)

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#2 2019-01-06 07:59:05

its4nitya
Member
Registered: 2018-12-15
Posts: 4

Re: [SOLVED] LUKS + UEFI - grub asking passphrase twice

The first time, it is grub that asks you for the password to decrypt the boot partition. The second time, it is the encrypt hook which asks you for the root partition's password. From your partition table, I infer that you have a single partition setup and boot and root are located on the same partition. If you do not want to be asked for your root partition password again, you will have to embed the keyfile in the initramfs and configure it to be used on system boot to decrypt and mount the root partition.
The following wiki post will help you configure the same.
https://wiki.archlinux.org/index.php/Dm … on_at_boot

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#3 2019-01-09 13:37:06

f1she3
Member
Registered: 2019-01-05
Posts: 6

Re: [SOLVED] LUKS + UEFI - grub asking passphrase twice

Hi, and thanks for your answer

In fact my arch linux (on my SSD) uses the windows' efi partition (on my HDD), wich is not encrypted, I just have one root partition on my SSD wich is encrypted.
So I think I shouldn't be asked to decrypt my boot ?

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#4 2019-01-09 21:10:54

respiranto
Member
Registered: 2015-05-15
Posts: 398
Website

Re: [SOLVED] LUKS + UEFI - grub asking passphrase twice

Your ESP (unencrypted) seems to be mounted at /boot/esp.  Hence /boot/* are on the root partition, which is encrypted.  You *might* want to mount your ESP at /boot to remove the necessity for GRUB to deal with decryption.

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#5 2019-01-10 04:04:16

its4nitya
Member
Registered: 2018-12-15
Posts: 4

Re: [SOLVED] LUKS + UEFI - grub asking passphrase twice

f1she3 wrote:

Hi, and thanks for your answer

In fact my arch linux (on my SSD) uses the windows' efi partition (on my HDD), wich is not encrypted, I just have one root partition on my SSD wich is encrypted.
So I think I shouldn't be asked to decrypt my boot ?

Your efi partition just contains the grub efi stub used to load the kernel and the initramfs. The kernel and the initramfs themselves are located on the /boot partition which is, in your case, located as a directory and not a partition, on the root partition itself. Thus, grub will ask you for your root partition password to decrypt boot. If you don't want grub to ask you for the password, you must create a separate boot partition and mount it to /boot at system startup.

Last edited by its4nitya (2019-01-10 04:04:59)

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#6 2019-01-13 21:18:06

f1she3
Member
Registered: 2019-01-05
Posts: 6

Re: [SOLVED] LUKS + UEFI - grub asking passphrase twice

respiranto wrote:

Your ESP (unencrypted) seems to be mounted at /boot/esp.  Hence /boot/* are on the root partition, which is encrypted.  You *might* want to mount your ESP at /boot to remove the necessity for GRUB to deal with decryption.

its4nitya wrote:

Your efi partition just contains the grub efi stub used to load the kernel and the initramfs. The kernel and the initramfs themselves are located on the /boot partition which is, in your case, located as a directory and not a partition, on the root partition itself. Thus, grub will ask you for your root partition password to decrypt boot. If you don't want grub to ask you for the password, you must create a separate boot partition and mount it to /boot at system startup.

Oh ok I understand now.

Thanks guys ! smile

f1she3

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