1
1
<?xml version="1.0" encoding="UTF-8"?>
2
2
<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN"
3
3
"http://www.oasis-open.org/docbook/xml/4.5/docbookx.dtd" [
4
<!ENTITY TIMESTAMP "2020-09-16">
4
<!ENTITY TIMESTAMP "2015-07-20">
5
5
<!ENTITY % common SYSTEM "common.ent">
68
64
The computers run a small client program in the initial RAM disk
69
65
environment which will communicate with a server over a network.
70
66
All network communication is encrypted using TLS. The clients
71
are identified by the server using a TLS public key; each client
67
are identified by the server using an OpenPGP key; each client
72
68
has one unique to it. The server sends the clients an encrypted
73
69
password. The encrypted password is decrypted by the clients
74
using a separate OpenPGP key, and the password is then used to
70
using the same OpenPGP key, and the password is then used to
75
71
unlock the root file system, whereupon the computers can
76
72
continue booting normally.
80
76
<refsect1 id="introduction">
81
77
<title>INTRODUCTION</title>
83
<!-- This paragraph is a combination and paraphrase of two
84
quotes from the 1995 movie “The Usual Suspects”. -->
85
79
You know how it is. You’ve heard of it happening. The Man
86
80
comes and takes away your servers, your friends’ servers, the
87
81
servers of everybody in the same hosting facility. The servers
133
127
So, at boot time, the Mandos client will ask for its encrypted
134
data over the network, decrypt the data to get the password, use
135
the password to decrypt the root file system, and the client can
136
then continue booting.
128
data over the network, decrypt it to get the password, use it to
129
decrypt the root file, and continue booting.
139
132
Now, of course the initial RAM disk image is not on the
145
138
long, and will no longer give out the encrypted key. The timing
146
139
here is the only real weak point, and the method, frequency and
147
140
timeout of the server’s checking can be adjusted to any desired
151
144
(The encrypted keys on the Mandos server is on its normal file
203
196
No. The server only gives out the passwords to clients which
204
197
have <emphasis>in the TLS handshake</emphasis> proven that
205
they do indeed hold the private key corresponding to that
198
they do indeed hold the OpenPGP private key corresponding to
384
377
plugin requirements.
388
<refsect1 id="systemd">
389
<title>SYSTEMD</title>
391
More advanced startup systems like <citerefentry><refentrytitle
392
>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
393
already have their own plugin-like mechanisms for allowing
394
multiple agents to independently retrieve a password and deliver
395
it to the subsystem requesting a password to unlock the root
396
file system. On these systems, it would make no sense to run
397
<citerefentry><refentrytitle>plugin-runner</refentrytitle
398
><manvolnum>8mandos</manvolnum></citerefentry>, the plugins of
399
which would largely duplicate the work of (and conflict with)
400
the existing systems prompting for passwords.
403
As for <citerefentry><refentrytitle>systemd</refentrytitle
404
><manvolnum>1</manvolnum></citerefentry> in particular, it has
406
url="https://systemd.io/PASSWORD_AGENTS/">Password
407
Agents</ulink> system. Mandos uses this via its
408
<citerefentry><refentrytitle>password-agent</refentrytitle
409
><manvolnum>8mandos</manvolnum></citerefentry> program, which is
410
run instead of <citerefentry><refentrytitle
411
>plugin-runner</refentrytitle><manvolnum>8mandos</manvolnum
412
></citerefentry> when <citerefentry><refentrytitle
413
>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>
414
is used during system startup.
419
<xi:include href="bugs.xml"/>
422
381
<refsect1 id="see_also">
423
382
<title>SEE ALSO</title>
434
393
<manvolnum>8</manvolnum></citerefentry>,
435
394
<citerefentry><refentrytitle>plugin-runner</refentrytitle>
436
395
<manvolnum>8mandos</manvolnum></citerefentry>,
437
<citerefentry><refentrytitle>password-agent</refentrytitle>
438
<manvolnum>8mandos</manvolnum></citerefentry>,
439
396
<citerefentry><refentrytitle>mandos-client</refentrytitle>
440
397
<manvolnum>8mandos</manvolnum></citerefentry>,
441
398
<citerefentry><refentrytitle>password-prompt</refentrytitle>
added
removed
intro.xml
