Installing Parabola GNU/Linux with full disk encryption (including /boot)

Libreboot uses the GRUB payload by default, which means that the GRUB configuration file (where your GRUB menu comes from) is stored directly alongside libreboot and it's GRUB payload executable, inside the flash chip. In context, this means that installing distributions and managing them is handled slightly differently compared to traditional BIOS systems.

On most systems, the /boot partition has to be left unencrypted while the others are encrypted. This is so that GRUB, and therefore the kernel, can be loaded and executed since the firmware can't open a LUKS volume. Not so with libreboot! Since GRUB is already included directly as a payload, even /boot can be encrypted. This protects /boot from tampering by someone with physical access to the machine.

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Boot Parabola's install environment. How to boot a GNU/Linux installer.

For this guide I used the 2013 09 01 image to boot the live installer and install the system.

This guide will go through the installation steps taken at the time of writing, which may or may not change due to the volatile nature of Parabola (it changes all the time). In general most of it should remain the same. If you spot mistakes, please say so! This guide will be ported to the Parabola wiki at a later date. For up to date Parabola install guide, go to the Parabola wiki. This guide essentially cherry picks the useful information (valid at the time of writing: 2014-09-15).

Firstly if you use an SSD, beware there are issues with TRIM (not enabled through luks) and security issues if you do enable it. See this page for more info.

If you are using an SSD for this, make sure it's brand-new (or barely used). Or, otherwise, be sure that it never previously contained plaintext copies of your data.

Wipe the MBR (if you use MBR):
# lsblk
Your HDD is probably /dev/sda: # dd if=/dev/zero of=/dev/sda bs=446 count=1; sync
Never use SeaBIOS! The MBR section can easily be changed with malicious code, which SeaBIOS will blindly execute. This guide is for libreboot with GRUB-as-payload only.

Securely wipe the drive:
# dd if=/dev/urandom of=/dev/sda; sync
NOTE: If you have an SSD, only do this the first time. If it was already LUKS-encrypted before, use the info below to wipe the LUKS header. Also, check online for your SSD what the recommended erase block size is. For example if it was 2MiB:
# dd if=/dev/urandom of=/dev/sda bs=2M; sync

If your drive was already LUKS encrypted (maybe you are re-installing your distro) then it is already 'wiped'. You should just wipe the LUKS header. https://www.lisenet.com/2013/luks-add-keys-backup-and-restore-volume-header/ showed me how to do this. It recommends doing the first 3MiB. Now, that guide is recommending putting zero there. I'm doing to use urandom. Do this:
# head -c 3145728 /dev/urandom > /dev/sda; sync
(wiping the LUKS header is important, since it has hashed passphrases and so on. It's 'secure', but 'potentially' a risk).

If you do plan to use an SSD, make sure to read https://wiki.archlinux.org/index.php/Solid_State_Drives
Edit /etc/fstab later on when chrooted into your install. Also, read the whole article and keep all points in mind, adapting them for this guide.

Change keyboard layout

Parabola live shell assumes US Qwerty. If you have something different, use:
# loadkeys LAYOUT
For me, LAYOUT would have been dvorak-uk.

Getting started

The beginning is based on https://wiki.parabolagnulinux.org/Installation_Guide. Then I referred to https://wiki.archlinux.org/index.php/Partitioning at first.

dm-mod

device-mapper will be used - a lot. Make sure that the kernel module is loaded:
# modprobe dm-mod

Create LUKS partition

I am using MBR partitioning, so I use cfdisk:
# cfdisk /dev/sda

I create a single large sda1 filling the whole drive, leaving it as the default type 'Linux' (83).

Now I refer to https://wiki.archlinux.org/index.php/Dm-crypt/Drive_preparation#Partitioning:
I am then directed to https://wiki.archlinux.org/index.php/Dm-crypt/Device_encryption.

Parabola forces you to RTFM.

It tells me to run:
# cryptsetup benchmark (for making sure the list below is populated)
Then:
# cat /proc/crypto
This gives me crypto options that I can use. It also provides a representation of the best way to set up LUKS (in this case, security is a priority; speed, a distant second). To gain a better understanding, I am also reading:
# man cryptsetup

Following that page, based on my requirements, I do the following based on https://wiki.archlinux.org/index.php/Dm-crypt/Device_encryption#Encryption_options_for_LUKS_mode. Reading through, it seems like Serpent (encryption) and Whirlpool (hash) is the best option.

I am initializing LUKS with the following:
# cryptsetup -v --cipher serpent-xts-plain64 --key-size 512 --hash whirlpool --use-random --verify-passphrase luksFormat /dev/sda1 -- choose a secure passphrase here. Ideally lots of lowercase/uppercase numbers, letters, symbols etc all in a random pattern. The password length should be as long as you are able to handle without writing it down or storing it anywhere.

Create LVM

Now I refer to https://wiki.archlinux.org/index.php/LVM.

Open the LUKS partition:
# cryptsetup open --type luks /dev/sda1 lvm
(it will be available at /dev/mapper/lvm)
I'm told that the above is old syntax, which is what I did anyway. You could also try:
# cryptsetup luksOpen /dev/sda1 lvm

Create LVM partition:
# pvcreate /dev/mapper/lvm
Show that you just created it:
# pvdisplay

Now I create the volume group, inside of which the logical volumes will be created:
# vgcreate matrix /dev/mapper/lvm (volume group name is 'matrix')
Show that you created it:
# vgdisplay

Now create the logical volumes:
# lvcreate -L 2G matrix -n swapvol (2G swap partition, named swapvol)
# lvcreate -l +100%FREE matrix -n rootvol (single large partition in the rest of the space, named rootvol)
You can also be flexible here, for example you can specify a /boot, a /, a /home, a /var, a /usr, etc. For example, if you will be running a web/mail server then you want /var in its own partition (so that if it fills up with logs, it won't crash your system). For a home/laptop system (typical use case), a root and a swap will do (really).

Verify that the logical volumes were created, using the following command:
# lvdisplay

Create / and swap partitions

For the swapvol LV I use:
# mkswap /dev/mapper/matrix-swapvol

For the rootvol LV I use:
# mkfs.ext4 /dev/mapper/matrix-rootvol

Continue with Parabola installation

Mount the root (/) partition:
# mount /dev/matrix/rootvol /mnt

This guide is really about GRUB, Parabola and cryptomount. I have to show how to install Parabola so that the guide can continue.

Now I am following the rest of https://wiki.parabolagnulinux.org/Installation_Guide. I also cross referenced https://wiki.archlinux.org/index.php/Installation_guide.

Create /home and /boot on rootvol mountpoint:
# mkdir /mnt/home
# mkdir /mnt/boot

The wiki says to enable the swap so that it can be detected by 'genfstab':
# swapon /dev/matrix/swapvol

DHCP was already working for me, so I had internet during the install. Therefore, I ignore the 'Connect to the Internet' section of the install guide. I also ignore wifi, since I can set that up after the install. For now, I am just using ethernet. Otherwise, refer to https://wiki.archlinux.org/index.php/Configuring_Network. You can test to see if internet is already working by pinging a few domains.

I commented out all lines except the Server line for the UK Parabola server (main server) in /etc/pacman.d/mirrorlist and then did:
# pacman -Syy
# pacman -Syu
# pacman -Sy pacman (and then I did the other 2 steps above, again)
In my case I did the steps in the next paragraph, and followed the steps in this paragraph again.

<troubleshooting>
   The following is based on 'Verification of package signatures' in the Parabola install guide.
   Check there first to see if steps differ by now.
   Now you have to update the default Parabola keyring. This is used for signing and verifying packages:
   # pacman -Sy parabola-keyring
   It says that if you get GPG errors, then it's probably an expired key and, therefore, you should do:
   # pacman-key --populate parabola
   # pacman-key --refresh-keys
   # pacman -Sy parabola-keyring
   To be honest, you should do the above anyway. Parabola has a lot of maintainers, and a lot of keys. Really!
   Also, it says that if the clock is set incorrectly then you have to manually set the correct time
   (if keys are listed as expired because of it):
   # date MMDDhhmm[[CC]YY][.ss]
   I also had to install:
   # pacman -S archlinux-keyring
   # pacman-key --populate archlinux
   In my case I saw some conflicting files reported in pacman, stopping me from using it.
   I deleted the files that it mentioned and then it worked. Specifically, I had this error:
   licenses: /usr/share/licenses/common/MPS exists in filesystem
   I rm -Rf'd the file and then pacman worked. I'm told that the following would have also made it work:
   # pacman -Sf licenses
</troubleshooting>

I also like to install other packages (base-devel, compilers and so on) and wpa_supplicant/dialog are needed for wireless after the install:
# pacstrap /mnt base base-devel wpa_supplicant dialog

Configure the system

From the Parabola installation guide (Arch's one was identical):
# genfstab -p /mnt >> /mnt/etc/fstab

Chroot into new system:
# arch-chroot /mnt

It's a good idea to have this installed:
# pacman -S linux-libre-lts

It was also suggested that you should install this kernel (read up on what GRSEC is):
# pacman -S linux-libre-grsec

This is another kernel that sits inside /boot, which you can use. LTS means 'long-term support'. These are so-called 'stable' kernels that can be used as a fallback during updates, if a bad kernel causes issues for you.

Parabola does not have wget. This is sinister. Install it:
# pacman -S wget

Set a root password

At the time of writing, Parabola used SHA512 by default for it's password hashing.

I referred to https://wiki.archlinux.org/index.php/SHA_password_hashes.

Open /etc/pam.d/passwd and add rounds=65536 at the end of the uncommented 'password' line.

# passwd root
Make sure to set a secure password! Also, it must never be the same as your LUKS password.

Extra security tweaks

Based on https://wiki.archlinux.org/index.php/Security.

Restrict access to important directories:
# chmod 700 /boot /etc/{iptables,arptables}

Lockout user after three failed login attempts:
Edit the file /etc/pam.d/system-login and comment out that line:
# auth required pam_tally.so onerr=succeed file=/var/log/faillog
Or just delete it. Above it, put:
auth required pam_tally.so deny=2 unlock_time=600 onerr=succeed file=/var/log/faillog
To unlock a user manually (if a password attempt is failed 3 times), do:
# pam_tally --user theusername --reset What the above configuration does is lock the user out for 10 minutes, if they make 3 failed login attempts.

Configure sudo - not covered here. Will be covered post-installation in another tutorial, at a later date. If this is a single-user system, you don't really need sudo.

Unmount, reboot!

Exit from chroot:
# exit

unmount:
# umount /mnt
# swapoff -a

deactivate the lvm lv's:
# lvchange -an /dev/matrix/rootvol
# lvchange -an /dev/matrix/swapvol

Lock the encrypted partition (close it):
# cryptsetup luksClose lvm

# shutdown -h now
Then boot up again.

Booting from GRUB

Initially you will have to boot manually. Press C to get to the GRUB command line. The underlined parts are optional (using those 2 underlines will boot lts kernel instead of normal).

grub> cryptomount -a (ahci0,msdos1)
grub> set root='lvm/matrix-rootvol'
grub> linux /boot/vmlinuz-linux-libre-lts root=/dev/matrix/rootvol cryptdevice=/dev/sda1:root
grub> initrd /boot/initramfs-linux-libre-lts.img
grub> boot

You could also make it load /boot/vmlinuz-linux-libre-grsec and /boot/initramfs-linux-libre-grsec.img

Modify grub.cfg inside the ROM

Now you need to modify the ROM, so that Parabola can boot automatically with this configuration. grub_cbfs.html shows you how. Follow that guide, using the configuration details below.

Inside the 'Load Operating System' menu entry, change the contents to:
cryptomount -a (ahci0,msdos1)
set root='lvm/matrix-rootvol'
linux /boot/vmlinuz-linux-libre-lts root=/dev/matrix/rootvol cryptdevice=/dev/sda1:root
initrd /boot/initramfs-linux-libre-lts.img

Note: the underlined parts above (-lts) can also be removed, to boot the latest kernel instead of LTS (long-term support) kernels. You could also copy the menu entry and in one have -lts, and without in the other menuentry. You could also create a menu entry to load /boot/vmlinuz-linux-libre-grsec and /boot/initramfs-linux-libre-grsec.img

Personally, I opted to have the entry for linux-libre-grsec at the top, so that it would load by default.

Above the 'Load Operating System' menu entry you should also add a GRUB password, like so: 

set superusers="root"
	password_pbkdf2 root grub.pbkdf2.sha512.10000.711F186347156BC105CD83A2ED7AF1EB971AA2B1EB2640172F34B0DEFFC97E654AF48E5F0C3B7622502B76458DA494270CC0EA6504411D676E6752FD1651E749.8DD11178EB8D1F633308FD8FCC64D0B243F949B9B99CCEADE2ECA11657A757D22025986B0FA116F1D5191E0A22677674C994EDBFADE62240E9D161688266A711

Note that the above entry specifies user 'root'; this is just a username for GRUB. You don't even need to use root. Change root on both of those 2 lines to whatever you want.

Start dhcp on ethernet:
# systemctl start dhcpcd.service This is just for the step below. I won't cover network configuration here. That is for another Parabola article.

The password hash (it's password, by the way) after 'password_pbkdf2 root' should be changed and is created by the grub-mkpasswd-pbkdf2 utility, which you need to install or otherwise compile, like so:
# pacman -S grub

GRUB isn't needed for booting, since it's already included as a payload in libreboot. This is only so that the utility needed becomes available. Get your hash by entering your chosen password at the prompt, when running this command:
# grub-mkpasswd-pbkdf2

It will output the hash for the password that you entered. Make sure to specify a password that is different from both your LUKS *and* your root/user password. Use it to replace the default hash mentioned above.

With this setup, you will have to enter a password at boot time, in GRUB, before being able to use any of the menu entries or switch to the terminal. This protects your system from an attacker simply booting a live usb distro and re-flashing the boot firmware.

You probably only need base-devel (compilers and so on) to build and use cbfstool. It was already installed if you followed this tutorial, but here it is:
# pacman -S base-devel

For flashing the modified ROM, I just used flashrom from the Parabola repo's:
# pacman -S flashrom
I also installed dmidecode:
# pacman -S dmidecode

When done, deleted GRUB (remember, we only needed it for the grub-mkpasswd-pbkdf2 utility; GRUB is already part of libreboot, flashed alongside it as a payload):
# pacman -R grub

If you followed all that correctly, you should now have a fully encrypted Parabola installation. This is a very barebones Parabola install (the default one). Refer to the wiki for how to do the rest (desktop, etc).

Optional: Use Keyfile in Initramfs to unlock encrypted root

Using the above installation method, you will have to unlock the encrypted file system twice (once in GRUB, and again when booting Parabola). To circumvent this, you can insert a keyfile into the initramfs. This is generally safe, because the /boot/ directory is encrypted.
First create a keyfile:
# dd bs=512 count=4 if=/dev/urandom of=/etc/mykeyfile iflag=fullblock
Add the keyfile to the Luks Device:
# cryptsetup luksAddKey /dev/sdX /etc/mykeyfile
Add the keyfile to the initramfs by adding it to FILES in /etc/mkinitcpio.conf. For example:
# FILES="/etc/mykeyfile"
Re-create the initramfs image:
# mkinitcpio -p linux-libre
Reboot and add the following to the kernel command line in GRUB:
# cryptkey=rootfs:/etc/mykeyfile

If everything works as expected, permanently add the kernel parameter to the GRUB config using the instructions at grub_cbfs.html.

Further security tips

https://wiki.archlinux.org/index.php/Security.
https://wiki.parabolagnulinux.org/User:GNUtoo/laptop

Follow-up tutorial: configuring Parabola

configuring_parabola.html shows my own notes post-installation. Using these, you can get a basic system similar to the one that I chose for myself. You can also cherry pick useful notes and come up with your own system. Parabola is user-centric, which means that you are in control. For more information, read The Arch Way (Parabola also follows it).

Copyright © 2014, 2015 Francis Rowe <info@gluglug.org.uk>
Copyright © 2015 Thomas Zelch <tze@xenlab.de>
This document is released under the Creative Commons Attribution-ShareAlike 4.0 International Public License and all future versions. A copy of the license can be found at ../cc-by-sa-4.txt.

This document is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See ../cc-by-sa-4.txt for more information.