Introduction

This is my installer for Arch Linux. It sets up a BTRFS system with encrypted /boot and full snapper support (both snapshotting and rollback work!). It also includes various system hardening configurations.

The script is based on easy-arch. However, it diverges substantially from the original project does not follow its development.

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How to use it?

1. Download an Arch Linux ISO from here
2. Flash the ISO onto an USB Flash Drive.
3. Boot the live environment.
4. Connect to the internet.
5. git clone https://github.com/tommytran732/Arch-Setup-Script/
6. cd Arch-Setup-Script
7. chmod u+x ./install.sh
8. ./install.sh

Snapper behavior

The partition layout I use allows us to replicate the behavior found in openSUSE 🦎

1. Snapper rollback works! You will no longer need to manually rollback from a live USB like you would with the @ and @home layout suggested in the Arch Wiki.
2. You can boot into a readonly snapshot! GDM and other services will start normally so you can get in and verify that everything works before rolling back.
3. Automatic snapshots on pacman install/update/remove operations
4. Directories such as /boot, /boot/efi, /var/log, /var/crash, /var/tmp, /var/spool, /var/lib/libvirt/images are excluded from the snapshots as they either should be persistent or are just temporary files. /cryptkey is excluded as we do not want the encryption key to be included in the snapshots, which could be sent to another device as a backup.
5. GRUB will boot into the default BTRFS snapshot set by snapper. Like on openSUSE, your running system will always be a read-write snapshot in @/.snapshots/X/snapshot.

Security considerations

Since this is an encrypted /boot setup, GRUB will prompt you for your encryption password and decrypt the drive so that it can access the kernel and initramfs. I am unaware of any way to make it use a TPM + PIN setup.

The implication of this is that an attacker can change your secure boot state with a programmer, replace your grubx64.efi and it will not be detected until its too late.

This type of attack can theoratically be solved by splitting /boot out to a seperate partition and encrypt the root filesystem separately. The key protector for the root filesystem can then be sealed to a TPM with PCR 0+1+2+3+5+7+14. It is a bit more complicated to set up so my installer does not support this (yet!).