Full disk encryption secure boot

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Revision as of 21:33, 26 July 2022 by Blt (talk | contribs) (Adding LUKS, Mounting points and File System and Installing Alpine)
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(Last edited by Blt on 26 Jul 2022.)

This guide is to explain step by step how to setup Alpine Linux with Full Disk Encryption using LUKS2, /boot & / together on the same partition, encrypted swap for hibernation on a nvme drive, with UEFI & Secure Boot. The goal of this guide is to follow the KISS principle, lvm can be added, another file system can be used, multiple partitions for /home; /var/log etc.. can also be added, if running everything in one partition is not meeting your requirements.

Sequence of Events

  • Installing packages
  • Partitioning the disk
  • Configuring LUKS
  • Mounting points and File System
  • Installing Alpine
  • Grub settings
  • mkinitfs settings & modules
  • Configuring Secure Boot

Installing packages

To facilitate the partitioning we will use gdisk :

# apk add gptfdisk

For encryption, we will use cryptsetup :

# apk add cryptsetup

For using and managing UEFI, multiple packages are needed :

# apk add e2fsprogs grub grub-efi

Partitioning the disk

Let's assume the disk is /dev/nvme0n1 and no partition is present, we will create three partitions :

  • one for UEFI
  • one for /
  • one for swap (hibernation)
# gdisk /dev/nvme0n1
Command (? for help): n
Partition number (1-128, default 1): 
First sector (2048-1000215182, default = 2048) or {+-}size{KMGTP}: 
Last sector (2048-1000215182, default = 1000214527) or {+-}size{KMGTP}: 512M
Hex code or GUID (L to show codes, Enter = 8300): ef00
Changed type of partition to 'EFI system partition'

Command (? for help): n
Partition number (2-128, default 2): 
First sector (1048577-1000215182, default = 1050624) or {+-}size{KMGTP}: 
Last sector (1050624-1000215182, default = 1000214527) or {+-}size{KMGTP}: 
Current type is 8300 (Linux filesystem)
Hex code or GUID (L to show codes, Enter = 8300): 8309
Changed type of partition to 'Linux LUKS'

Command (? for help): w

Final checks complete. About to write GPT data. THIS WILL OVERWRITE EXISTING
PARTITIONS!!

Do you want to proceed? (Y/N): Y
OK; writing new GUID partition table (GPT) to /dev/nvme0n1.
The operation has completed successfully.

Configuring LUKS

# cryptsetup -v -c aes-xts-plain64 -s 512 --hash sha512 --pbkdf pbkdf2 --iter-time 5000 --use-random luksFormat /dev/nvme0n1p2

WARNING!
========
This will overwrite data on /dev/nvme0n1p2 irrevocably.

Are you sure? (Type 'yes' in capital letters): YES
Enter passphrase for /dev/nvme0n1p2: 
Verify passphrase: 
Key slot 0 created.
Command successful.

cryptsetup -v -c aes-xts-plain64 -s 512 --hash sha512 --pbkdf pbkdf2 --iter-time 5000 --use-random luksFormat /dev/nvme0n1p3

WARNING!
========
This will overwrite data on /dev/nvme0n1p3 irrevocably.

Are you sure? (Type 'yes' in capital letters): YES
Enter passphrase for /dev/nvme0n1p3: 
Verify passphrase: 
Key slot 0 created.
Command successful.

Mounting points and File System

Open the LUKS partitiond we just created:

# cryptsetup luksOpen /dev/nvme0n1p2 nvme0n1p2-crypt
# cryptsetup luksOpen /dev/nvme0n1p3 nvme0n1p3-crypt

Create vfat file system for UEFI partition:

# mkfs.vfat /dev/nvme0n1p1

Create ext4 file system for / partition:

# mkfs.ext4 /dev/mapper/nvme0n1p2-crypt

Create ext4 file system for swap partition:

# mkfs.ext4 /dev/mapper/nvme0n1p3-crypt

Create mounting points and mount partitions : Mount / partition to /mnt :

# mount -t ext4 /dev/mapper/nvme0n1p2-crypt /mnt

Create /boot/efi:

# mkdir /mnt/boot/efi -p

Mount UEFI partition to /mnt/boot/efi :

# mount -t ext4 /dev/mapper/nvme0n1p1 /mnt/boot/efi

Installing Alpine

# setup-disk -m sys /mnt/

Grub settings

mkinitfs settings & modules

Configuring Secure Boot