aboutsummaryrefslogtreecommitdiffstats
path: root/README-mkinitcpio.md
blob: 9f2ee4ac97178c9c81f06cd1b5e6b4d34d96b685 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
Full disk encryption with Yubikey (Yubico key) for mkinitcpio
=============================================================

This allows to automatically unlock a LUKS encrypted hard disk from `systemd`-
enabled initramfs.

Requirements
------------

To compile and use yubikey full disk encryption you need:

* [yubikey-personalization](https://github.com/Yubico/yubikey-personalization)
* [iniparser](http://ndevilla.free.fr/iniparser/)
* [systemd](http://www.freedesktop.org/wiki/Software/systemd/)
* [cryptsetup](http://code.google.com/p/cryptsetup/)
* keyutils and linux with `CONFIG_KEYS`
* [mkinitcpio](https://projects.archlinux.org/mkinitcpio.git/)
* [markdown](http://daringfireball.net/projects/markdown/) (HTML documentation)
* [libarchive](http://www.libarchive.org/) (Update challenge on boot)

Additionally it is expected to have `make` and `pkg-config` around to
successfully compile.

Build and install
-----------------

Building and installing is very easy. Just run:

> make

followed by:

> make install-mkinitcpio

This will place files to their desired places in filesystem.

Usage
-----

### config files `/etc/crypttab.initramfs` and `/etc/ykfde.conf`

Make sure systemd knows about your encrypted device by
adding a line to `/etc/crypttab.initramfs`. It should read like:

> `mapping-name` /dev/`LUKS-device` -

Usually there is already an entry for your device.

Update `/etc/ykfde.conf` with correct settings. Add `mapping-name` from
above to `device name` in the `general` section. Then add a new section
with your key's decimal serial number containing the key slot setting.
The minimal file should look like this:

    [general]
    device name = crypt

    [1234567]
    luks slot = 1

*Be warned*: Do not remove or overwrite your interactive key! Keep that
for backup and rescue!

### key setup

`ykfde` will read its information from these files and understands some
additional options. Run `ykfde --help` for details. Then prepare
the key. Plug it in, make sure it is configured for `HMAC-SHA1`.
After that run:

> ykfde

This will store a challenge in `/etc/ykfde.d/` and add a new slot to
your LUKS device. When `ykfde` asks for a passphrase it requires a valid
passphrase from available slot.

Alternatively, adding a key with second factor (`foo` in this example)
is as easy:

> ykfde --new-2nd-factor foo

To update the challenge run:

> ykfde --2nd-factor foo

And changing second factor (from `foo` to `bar` in this example) is
straight forward:

> ykfde --2nd-factor foo --new-2nd-factor bar

The current and new second factor can be read from terminal, increasing
security by not displaying on display and not writing to shell history.
Use switches `--ask-2nd-factor` and `--ask-new-2nd-factor` for that.

Make sure to enable second factor in `/etc/ykfde.conf`.

### cpio archive with challenges

Every time you update a challenge and/or a second factor run:

> ykfde-cpio

This will write a cpio archive `/boot/ykfde-challenges.img` containing
your current challenges. Enable systemd service `ykfde` to do this
automatically on every boot:

> systemctl enable ykfde.service

### mkinitcpio hook `ykfde`

Last add `ykfde` to your hook list in `/etc/mkinitcpio.conf`. You should
already have `systemd` and `sd-encrypt` there as a `systemd`-enabled
initramfs is prerequisite. Now rebuild your initramfs with:

> mkinitcpio -p linux

### boot loader

Update you `grub` configuration by running:

> grub-mkconfig -o /boot/grub/grub.cfg

This will add new boot entry that loads the challenges. With other boot
loaders make sure to load the cpio archive `/boot/ykfde-challenges.img`
as additional initramfs.

Reboot and have fun!