Encrypted Root

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Revision as of 17:44, December 10, 2021 by Seemant (talk | contribs) (put the 32-bit command after the 64 bit one)
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This howto describes how to setup LVM, swap, and root with dmcrypt LUKS. It is a standalone installation walk through, based on the official installations finished product. boot is not encrypted.


You may try this installation method at your own risk! Please note: this guide is outside of the official installation documentation and cannot be supported. If you choose to use this, we assume you know what you are doing and you are on your own.

Prepare the hard drive and partitions

  • Before you begin, make sure you are partitioning the correct drive. For the rest of this tutorial, we will be using /dev/sdX as a placeholder.
root # lsblk
sda             8:0    0  1.8T  0 disk 
├─sda1          8:1    0  512M  0 part 
├─sda2          8:2    0    8G  0 part [SWAP]
└─sda3          8:3    0  1.8T  0 part 
  ├─main-root 254:0    0  500G  0 lvm  /
  └─main-data 254:1    0  1.3T  0 lvm  /home


MBR [BIOS] Partitioning


Use this method if you are booting using your BIOS, and if your Funtoo LiveCD initial boot menu was light blue. If you're going to use the UEFI/GPT disk format, then please proceed to the next section.

root # fdisk /dev/sdX

Within fdisk, follow these steps:

Empty the partition table:

Command (m for help): o ↵

Create boot partition:

Command (m for help): n ↵
Partition type (default p): 
Partition number (1-4, default 1): 
First sector: 
Last sector: +128M ↵

Create partition which will be encrypted with LUKS:

Command (m for help): n ↵
Partition type (default p): 
Partition number (2-4, default 2): 
First sector: 
Last sector: 

Verify the partition table:

Command (m for help): p

Disk /dev/sdX: 298.1 GiB, 320072933376 bytes, 625142448 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: dos
Disk identifier: 0x82abc9a6

Device    Boot     Start       End    Blocks  Id System
/dev/sdX1           2048    264191    131072  83 Linux
/dev/sdX2        4458496 625142447 312439128  83 Linux

Write the partition table to disk:

Command (m for help): w

Your new MBR partition table will now be written to your system disk.

UEFI Partitioning


Use this method if you are interested in booting using UEFI, and if your Funtoo LiveCD initial boot menu was black and white, or the system booted without a boot menu. If it was light blue, this method will not work. Instead, use the instructions in the previous section then skip this section, or reboot LiveCD in UEFI mode first.

root # gdisk /dev/sdX

Within gdisk, follow these steps:

Empty the partition table:

Command: o ↵
This option deletes all partitions and creates a new protective MBR.
Proceed? (Y/N): y ↵

Create boot partition:

Command: n ↵
Partition Number: 1 ↵
First sector: 
Last sector: +128M ↵
Hex Code: EF00 ↵

Create partition which will be encrypted with LUKS:

Command: n ↵
Partition Number: 2 ↵
First sector: 
Last sector:  (for rest of disk)
Hex Code: 

(Optional) Create disk labels:

Command: c ↵
Partition Number: 1
Enter name: BOOT 
Command: c ↵
Partition Number: 2
Enter name: ROOT

Write Partition Table To Disk:

Command: w ↵
Do you want to proceed? (Y/N): Y ↵

The partition table will now be written to the disk and gdisk will close.

Create and mount filesystems.

Create /boot filesystem

For BIOS systems

root # mkfs.ext2 /dev/sdX1

For UEFI systems

root # mkfs.vfat -F 32 /dev/sdX1

Create LUKS encrypted volume


Cryptsetup now defaults to LUKS2, which is unsupported by stable versions of grub. This is why we are not encrypting /boot.


The debian-sources kernel in current stage3 tarballs does not allow for passwords in excess of 63 characters.

root # cryptsetup luksFormat /dev/sdX2

Open newly created LUKS volume

root # cryptsetup open --type luks2 /dev/sdX2 root

Create LVM volumes for / and swap

root # pvcreate /dev/mapper/root
root # vgcreate vg /dev/mapper/root

Replace "16G" with the amount of swap you would like to make available.

root # lvcreate -L16G --name swap vg
root # lvcreate -l 100%FREE --name root vg

The "-l 100%FREE" option above will use the remainder of the disk for your root partition. If you would prefer to create separate for /home or /var (for example), you can instead continue to use the "-LXXG" option for fixed sizes.

Create filesystems on LVM volumes

root # mkswap /dev/mapper/vg-swap
root # mkfs.ext4 /dev/mapper/vg-root

Create directories for chroot

root # mkdir -p /mnt/funtoo

Mount filesystems

root # mount /dev/mapper/vg-root /mnt/funtoo
root # mkdir /mnt/funtoo/boot
root # mount /dev/sdX1 /mnt/funtoo/boot
root # mkdir /mnt/funtoo/proc
root # mount -t proc none /mnt/funtoo/proc
root # mkdir /mnt/funtoo/dev
root # mount --rbind /dev /mnt/funtoo/dev
root # mkdir /mnt/funtoo/sys
root # mount --rbind /sys /mnt/funtoo/sys

Set the date


See the official Funtoo docs on setting the date.

Install the Funtoo starge tarball of your choice


These instructions will be using the intel-haswell minimal stage3. You should adjust them accordingly

root # cd /mnt/funtoo
root # wget https://build.funtoo.org/1.4-release-std/x86-64bit/intel64-haswell/2021-03-10/stage3-intel64-haswell-1.4-release-std-2021-03-10.tar.xz
root # tar --numeric-owner --xattrs --xattrs-include='*' -xpf stage3-intel64-haswell-1.4-release-std-2021-03-10.tar.xz && rm -f stage3-intel64-haswell-1.4-release-std-2021-03-10.tar.xz

Chroot into your new system

root # cp /etc/resolv.conf /mnt/funtoo/etc/
root # env -i HOME=/root TERM=$TERM $(which chroot) /mnt/funtoo bash -l

Configure your system

Set a new root password

root # passwd

Set hostname

root # echo 'hostname="yourdesiredhostname"' > /etc/conf.d/hostname

Set your timezone

root # ln -sf /usr/share/zoneinfo/YOUR/TIMEZONE /etc/localtime

Note your filesystem information

root # blkid
/dev/sdX1: UUID="6453-0C55" TYPE="vfat" PARTLABEL="efi" PARTUUID="4e195c4b-f88c-4205-b9df-79a879704b2f"
/dev/sdX2: UUID="aafe709b-82e7-448f-a2cb-36adc3787dc3" TYPE="crypto_LUKS" PARTLABEL="system" PARTUUID="93d0cf9b-0b95-4d8b-919f-48cd1774996f"
/dev/mapper/root: UUID="hvz79n-I2VE-nR1c-0hDQ-PVkR-3GRb-rnuJ9C" TYPE="LVM2_member"
/dev/mapper/vg-swap: UUID="a9188bc3-7def-422b-990d-9de431825779" TYPE="swap"
/dev/mapper/vg-root: UUID="2eaf45e6-d33b-4155-b4ca-63a2fdbfb896" TYPE="ext4"

Configure /etc/fstab


The UUID parameter is set to the UUID of your boot partition as found from the blkid command above.

root # cat > /etc/fstab << 'EOF'
UUID=6453-0C55 /boot vfat noauto,noatime 1 2
/dev/mapper/vg-swap none swap sw 0 0
/dev/mapper/vg-root / ext4 noatime,nodiratime,defaults 0 1

Create /etc/crypttab


The UUID parameter is set to the UUID of /dev/sdX2 as found from the blkid command above.

root # echo "root UUID=aafe709b-82e7-448f-a2cb-36adc3787dc3 none luks,discard" >> /etc/crypttab

Create /etc/dmtab

root # dmsetup table >> /etc/dmtab


Download the portage tree

root # ego sync

Change your ego profile to include encrypted root support

root # epro mix-in encrypted-root

Edit package USE-flags

root # cat > /etc/portage/package.use <<'EOF'
*/* device-mapper lvm luks
sys-kernel/linux-firmware initramfs
sys-fs/cryptsetup -dynamic

Install necessary packages

root # emerge grub haveged intel-microcode linux-firmware cryptsetup lvm2 genkernel iucode_tool

Configure services to start at boot

root # rc-update add device-mapper sysinit
root # rc-update add dmcrypt sysinit
root # rc-update add lvmetad sysinit
root # rc-update add haveged default
root # rc-update add busybox-ntpd default

Install a bootloader

Configure /etc/boot.conf


The UUID parameter is set to the UUID of /dev/sdX2 as found from the blkid command above.

root # cat > /etc/boot.conf <<'EOF'
boot {
    generate grub
    default "Funtoo Linux"
    timeout 3
"Funtoo Linux" {
    kernel kernel[-v]
    initrd initramfs[-v]
    params += crypt_root=UUID=aafe709b-82e7-448f-a2cb-36adc3787dc3 dolvm real_root=/dev/mapper/vg-root ro rootfstype=ext4 resume=swap:/dev/mapper/vg-swap quiet

Install GRUB

For BIOS systems

root # grub-install --target=i386-pc --no-floppy /dev/sdX
root # ego boot update

For UEFI systems

root # mount -o remount,rw /sys/firmware/efi/efivars
root # grub-install --target=x86_64-efi --efi-directory=/boot --bootloader-id="Funtoo Linux" --recheck /dev/sdX

For 32 bit systems, the following command should be changed to:

root # grub-install --target=i386-efi --efi-directory=/boot --bootloader-id="Funtoo Linux" --recheck /dev/sdX
root # ego boot update

Patch genkernel to include LUKS2 support

root # sed '/MODULES_CRYPT/ s/\"$/ af_alg algif_skcipher\"/' -i /usr/share/genkernel/arch/$(arch)/modules_load

Generate a new initramfs

root # genkernel --clean --luks --lvm --disklabel --ramdisk-modules --fullname=$(ls /boot/initramfs-* | tail -c +17) initramfs

Finishing installation

From this point, you should be able to finish following the official Funtoo Linux install instructions

Managing your LUKS volume

Change your LUKs-encrypted drive's passphrase You may want to change your encrypted volume’s passphrase or password from time to time. To do so, run the following commands in the console as root:

root # cryptsetup luksChangeKey /dev/sdx3

You'll be prompted to enter in the existing passphrase first, then to enter in your new passphrase. You will not be asked to confirm your new passphrase, so be careful when running this operation.

Additional links and information