encrypted_debian.md 13 KB
% Installing Debian or Devuan GNU+Linux with full disk encryption (including /boot)
This guide is written for the Debian distribution, but it should also work for Devuan with the net installer.
Libreboot on x86 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 its 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 system.
This guide is written for Debian net installer. You can download the ISO from the homepage on debian.org. Use this on the GRUB terminal to boot it from USB (for 64-bit Intel or AMD):\ **set root='usb0'\ linux /install.amd/vmlinuz\ initrd /install.amd/initrd.gz\ boot\ ** If you are on a 32-bit system (e.g. X60):\ set root='usb0'\ linux /install.386/vmlinuz\ initrd /install.386/initrd.gz\ boot
This guide shows how to create a boot USB drive with the Debian ISO image.
This guide is *only* for the GRUB payload. If you use the depthcharge payload, ignore this section entirely.
Note: on some thinkpads, a faulty DVD drive can cause the cryptomount -a step during boot to fail. If this happens to you, try removing the drive.
Set a strong user password (lots of lowercase/uppercase, numbers and symbols).
Use of the diceware method is recommended, for generating secure passphrases (instead of passwords).
when the installer asks you to set up encryption (ecryptfs) for your home directory, select 'Yes' if you want to: LUKS is already secure and performs well. Having ecryptfs on top of it will add noticeable performance penalty, for little security gain in most use cases. This is therefore optional, and not recommended. Choose 'no'.
Your user password should be different from the LUKS password which you will set later on. Your LUKS password should, like the user password, be secure.
Partitioning
Choose 'Manual' partitioning:
- Select drive and create new partition table
Single large partition. The following are mostly defaults:
- Use as: physical volume for encryption
- Encryption: aes
- key size: whatever default is given to you
- IV algorithm: whatever default is given to you
- Encryption key: passphrase
- erase data: Yes (only choose 'No' if it's a new drive that doesn't contain your private data)
Select 'configure encrypted volumes'
- Create encrypted volumes
- Select your partition
- Finish
- Really erase: Yes
- (erase will take a long time. be patient)
- (if your old system was encrypted, just let this run for about a minute to make sure that the LUKS header is wiped out)
Select encrypted space:
- use as: physical volume for LVM
- Choose 'done setting up the partition'
Configure the logical volume manager:
- Keep settings: Yes
Create volume group:
- Name: matrix (use this exact name)
- Select crypto partition
Create logical volume
- select matrix (use this exact name)
- name: rootvol (use this exact name)
- size: default, minus 2048 MB
Create logical volume
- select matrix (use this exact name)
- name: swap (user this exact name)
- size: press enter
Further partitioning
Now you are back at the main partitioning screen. You will simply set mountpoints and filesystems to use.
- LVM LV rootvol
- use as: btrfs
- mount point: /
- done setting up partition
- LVM LV swap
- use as: swap area
- done setting up partition
- Now you select 'Finished partitioning and write changes to disk'.
Kernel
Installation will ask what kernel you want to use. linux-generic is fine.
Tasksel
For Debian, use the MATE option, or one of the others if you want. The libreboot project recommends MATE, unless you're saavy enough to choose something else.
If you want debian-testing, then you should only select barebones options here and change the entries in /etc/apt/sources.list after install to point to the new distro, and then run apt-get update and apt-get dist-upgrade as root, then reboot and run tasksel as root. This is to avoid downloading large packages twice.
NOTE: If you want the latest up to date version of the Linux kernel, Debian's kernel is sometimes outdated, even in the testing distro. You might consider using this repository instead, which contains the most up to date versions of the Linux kernel. These kernels are also deblobbed, like Debian's kernels, so you can be sure that no binary blobs are present.
Postfix configuration
If asked, choose "No Configuration" here (or maybe you want to select something else. It's up to you.)
Install the GRUB boot loader to the master boot record
Choose 'Yes'. It will fail, but don't worry. Then at the main menu, choose 'Continue without a bootloader'. You could also choose 'No'. Choice is irrelevant here.
You do not need to install GRUB at all, since in libreboot you are using the GRUB payload (for libreboot) to boot your system directly.
Clock UTC
Just say 'Yes'.
Booting your system
At this point, you will have finished the installation. At your GRUB payload, press C to get to the command line.
Do that:
grub> cryptomount -a
grub> set root='lvm/matrix-rootvol'\
grub> linux /vmlinuz root=/dev/mapper/matrix-rootvol cryptdevice=/dev/mapper/matrix-rootvol:root
grub> initrd /initrd.img
grub> boot
ecryptfs
If you didn't encrypt your home directory, then you can safely ignore this section.
Immediately after logging in, do that:
$ sudo ecryptfs-unwrap-passphrase
This will be needed in the future if you ever need to recover your home directory from another system, so write it down and keep the note somewhere secret. Ideally, you should memorize it and then burn the note (or not even write it down, and memorize it still)>
Modify grub.cfg (CBFS)
Now you need to set it up so that the system will automatically boot, without having to type a bunch of commands.
Modify your grub.cfg (in the firmware) using this tutorial; just change the default menu entry 'Load Operating System' to say this inside:
cryptomount -a\ set root='lvm/matrix-rootvol'\ linux /vmlinuz root=/dev/mapper/matrix-rootvol cryptdevice=/dev/mapper/matrix-rootvol:root\ initrd /initrd.img
Without specifying a device, the -a parameter tries to unlock all detected LUKS volumes. You can also specify -u UUID or -a (device).
Refer to this guide for further guidance on hardening your GRUB configuration, for security purposes.
Flash the modified ROM using this tutorial.
Troubleshooting
A user reported issues when booting with a docking station attached on an X200, when decrypting the disk in GRUB. The error AHCI transfer timed out was observed. The workaround was to remove the docking station.
Further investigation revealed that it was the DVD drive causing problems. Removing that worked around the issue.
"sudo wodim -prcap" shows information about the drive:
Device was not specified. Trying to find an appropriate drive...
Detected CD-R drive: /dev/sr0
Using /dev/cdrom of unknown capabilities
Device type : Removable CD-ROM
Version : 5
Response Format: 2
Capabilities :
Vendor_info : 'HL-DT-ST'
Identification : 'DVDRAM GU10N '
Revision : 'MX05'
Device seems to be: Generic mmc2 DVD-R/DVD-RW.
Drive capabilities, per MMC-3 page 2A:
Does read CD-R media
Does write CD-R media
Does read CD-RW media
Does write CD-RW media
Does read DVD-ROM media
Does read DVD-R media
Does write DVD-R media
Does read DVD-RAM media
Does write DVD-RAM media
Does support test writing
Does read Mode 2 Form 1 blocks
Does read Mode 2 Form 2 blocks
Does read digital audio blocks
Does restart non-streamed digital audio reads accurately
Does support Buffer-Underrun-Free recording
Does read multi-session CDs
Does read fixed-packet CD media using Method 2
Does not read CD bar code
Does not read R-W subcode information
Does read raw P-W subcode data from lead in
Does return CD media catalog number
Does return CD ISRC information
Does support C2 error pointers
Does not deliver composite A/V data
Does play audio CDs
Number of volume control levels: 256
Does support individual volume control setting for each channel
Does support independent mute setting for each channel
Does not support digital output on port 1
Does not support digital output on port 2
Loading mechanism type: tray
Does support ejection of CD via START/STOP command
Does not lock media on power up via prevent jumper
Does allow media to be locked in the drive via PREVENT/ALLOW command
Is not currently in a media-locked state
Does not support changing side of disk
Does not have load-empty-slot-in-changer feature
Does not support Individual Disk Present feature
Maximum read speed: 4234 kB/s (CD 24x, DVD 3x)
Current read speed: 4234 kB/s (CD 24x, DVD 3x)
Maximum write speed: 4234 kB/s (CD 24x, DVD 3x)
Current write speed: 4234 kB/s (CD 24x, DVD 3x)
Rotational control selected: CLV/PCAV
Buffer size in KB: 1024
Copy management revision supported: 1
Number of supported write speeds: 4
Write speed # 0: 4234 kB/s CLV/PCAV (CD 24x, DVD 3x)
Write speed # 1: 2822 kB/s CLV/PCAV (CD 16x, DVD 2x)
Write speed # 2: 1764 kB/s CLV/PCAV (CD 10x, DVD 1x)
Write speed # 3: 706 kB/s CLV/PCAV (CD 4x, DVD 0x)
Supported CD-RW media types according to MMC-4 feature 0x37:
Does write multi speed CD-RW media
Does write high speed CD-RW media
Does write ultra high speed CD-RW media
Does not write ultra high speed+ CD-RW media
Copyright © 2014, 2015, 2016 Leah Rowe info@minifree.org\ Permission is granted to copy, distribute and/or modify this document under the terms of the Creative Commons Attribution-ShareAlike 4.0 International license or any later version published by Creative Commons; A copy of the license can be found at ../cc-by-sa-4.0.txt
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