blob: 31a30478cbae5b8764a03daac8fa21a123bb436a (
about) (
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
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
|
Full disk encryption with Yubikey (Yubico key) for mkinitcpio
=============================================================
This enables you to automatically unlock a LUKS encrypted filesystem from
a `systemd`-enabled initramfs.
Requirements
------------
To compile and use Yubikey full disk encryption you need:
* [yubikey-personalization](https://github.com/Yubico/yubikey-personalization)
* [iniparser](https://github.com/ndevilla/iniparser)
* [systemd](https://www.github.com/systemd/systemd)
* [cryptsetup](https://gitlab.com/cryptsetup/cryptsetup)
* keyutils and linux with `CONFIG_KEYS` enabled
* [mkinitcpio](https://projects.archlinux.org/mkinitcpio.git/)
* [markdown](https://daringfireball.net/projects/markdown/) (HTML documentation)
* [libarchive](https://www.libarchive.org/) (Update challenge on boot)
Additionally you will need to have `make` and `pkg-config` installed to
successfully compile.
Build and install
-----------------
Building and installing is very easy. Just run:
> make
followed by:
> make install-mkinitcpio
This will place the files in their desired places in the filesystem.
Keep in mind that you need `root` privileges for installation, so switch
user or prepend the last command with `sudo`.
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. If you do not already
have a `systemd`-enabled initramfs, you will need to create this file from
scratch.
Update `/etc/ykfde.conf` with correct settings. Add the value of
`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 (regular) key!
Keep that for backup and rescue - LUKS encrypted volumes have a total
of 8 slots (from 0 to 7).
### 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 and make sure it is configured for `HMAC-SHA1`. This can
be done with `ykpersonalize` from terminal (package `yubikey-personalization`)
or with GUI application `YubiKey Personalization Tool` (package
`yubikey-personalization-gui`). After that, run:
> ykfde
This will store a challenge in `/etc/ykfde.d/` and add a new slot to
your LUKS device based on the `/etc/ykfde.conf` configuration. When
`ykfde` asks for a passphrase it requires a valid passphrase from a
previously 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 to `/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`
Lastly, 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. A working example config is as follows:
> HOOKS="base systemd keyboard autodetect modconf block ykfde sd-encrypt sd-lvm2 filesystems fsck"
Now rebuild your initramfs with:
> mkinitcpio -p linux
### Boot loader
Make sure to load the cpio archive `/boot/ykfde-challenges.img`
as an additional initramfs. It has to be listed *after* microcode
updates (if available), but *before* main initramfs.
With `grub` you need to list `ykfde-challenges.img` in configuration
variable `GRUB_EARLY_INITRD_LINUX_CUSTOM` in `/etc/default/grub`:
> GRUB_EARLY_INITRD_LINUX_CUSTOM="ykfde-challenges.img"
Then update your `grub` configuration by running:
> grub-mkconfig -o /boot/grub/grub.cfg
A valid configuration for `systemd-boot` should be placed in
`/boot/loader/entries/default.conf` and look something like this:
```
title Default
linux /vmlinuz-linux
initrd /intel-ucode.img
initrd /ykfde-challenges.img
initrd /initramfs-linux.img
options root=... rw quiet
```
Reboot and have fun!
|