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 VERSION "1.0">
4
5
<!ENTITY COMMANDNAME "mandos">
5
<!ENTITY TIMESTAMP "2022-04-24">
6
<!ENTITY % common SYSTEM "common.ent">
6
<!ENTITY TIMESTAMP "2008-08-31">
10
9
<refentry xmlns:xi="http://www.w3.org/2001/XInclude">
12
11
<title>Mandos Manual</title>
13
12
<!-- NWalsh’s docbook scripts use this to generate the footer: -->
14
13
<productname>Mandos</productname>
15
<productnumber>&version;</productnumber>
14
<productnumber>&VERSION;</productnumber>
16
15
<date>&TIMESTAMP;</date>
19
18
<firstname>Björn</firstname>
20
19
<surname>Påhlsson</surname>
22
<email>belorn@recompile.se</email>
21
<email>belorn@fukt.bsnet.se</email>
26
25
<firstname>Teddy</firstname>
27
26
<surname>Hogeborn</surname>
29
<email>teddy@recompile.se</email>
28
<email>teddy@fukt.bsnet.se</email>
46
34
<holder>Teddy Hogeborn</holder>
47
35
<holder>Björn Påhlsson</holder>
49
<xi:include href="legalnotice.xml"/>
39
This manual page is free software: you can redistribute it
40
and/or modify it under the terms of the GNU General Public
41
License as published by the Free Software Foundation,
42
either version 3 of the License, or (at your option) any
47
This manual page is distributed in the hope that it will
48
be useful, but WITHOUT ANY WARRANTY; without even the
49
implied warranty of MERCHANTABILITY or FITNESS FOR A
50
PARTICULAR PURPOSE. See the GNU General Public License
55
You should have received a copy of the GNU General Public
56
License along with this program; If not, see
57
<ulink url="http://www.gnu.org/licenses/"/>.
53
63
<refentrytitle>&COMMANDNAME;</refentrytitle>
54
64
<manvolnum>8</manvolnum>
95
105
<replaceable>DIRECTORY</replaceable></option></arg>
97
107
<arg><option>--debug</option></arg>
99
<arg><option>--debuglevel
100
<replaceable>LEVEL</replaceable></option></arg>
102
<arg><option>--no-dbus</option></arg>
104
<arg><option>--no-ipv6</option></arg>
106
<arg><option>--no-restore</option></arg>
108
<arg><option>--statedir
109
<replaceable>DIRECTORY</replaceable></option></arg>
111
<arg><option>--socket
112
<replaceable>FD</replaceable></option></arg>
114
<arg><option>--foreground</option></arg>
116
<arg><option>--no-zeroconf</option></arg>
119
110
<command>&COMMANDNAME;</command>
131
122
<arg choice="plain"><option>--check</option></arg>
133
124
</refsynopsisdiv>
135
126
<refsect1 id="description">
136
127
<title>DESCRIPTION</title>
138
129
<command>&COMMANDNAME;</command> is a server daemon which
139
handles incoming requests for passwords for a pre-defined list
140
of client host computers. For an introduction, see
141
<citerefentry><refentrytitle>intro</refentrytitle>
142
<manvolnum>8mandos</manvolnum></citerefentry>. The Mandos server
143
uses Zeroconf to announce itself on the local network, and uses
144
TLS to communicate securely with and to authenticate the
145
clients. The Mandos server uses IPv6 to allow Mandos clients to
146
use IPv6 link-local addresses, since the clients will probably
147
not have any other addresses configured (see <xref
148
linkend="overview"/>). Any authenticated client is then given
149
the stored pre-encrypted password for that specific client.
130
handles incoming request for passwords for a pre-defined list of
131
client host computers. The Mandos server uses Zeroconf to
132
announce itself on the local network, and uses TLS to
133
communicate securely with and to authenticate the clients. The
134
Mandos server uses IPv6 to allow Mandos clients to use IPv6
135
link-local addresses, since the clients will probably not have
136
any other addresses configured (see <xref linkend="overview"/>).
137
Any authenticated client is then given the stored pre-encrypted
138
password for that specific client.
153
143
<refsect1 id="purpose">
154
144
<title>PURPOSE</title>
156
147
The purpose of this is to enable <emphasis>remote and unattended
157
148
rebooting</emphasis> of client host computer with an
158
149
<emphasis>encrypted root file system</emphasis>. See <xref
159
150
linkend="overview"/> for details.
163
155
<refsect1 id="options">
164
156
<title>OPTIONS</title>
167
160
<term><option>--help</option></term>
219
212
<xi:include href="mandos-options.xml" xpointer="debug"/>
224
<term><option>--debuglevel
225
<replaceable>LEVEL</replaceable></option></term>
228
Set the debugging log level.
229
<replaceable>LEVEL</replaceable> is a string, one of
230
<quote><literal>CRITICAL</literal></quote>,
231
<quote><literal>ERROR</literal></quote>,
232
<quote><literal>WARNING</literal></quote>,
233
<quote><literal>INFO</literal></quote>, or
234
<quote><literal>DEBUG</literal></quote>, in order of
235
increasing verbosity. The default level is
236
<quote><literal>WARNING</literal></quote>.
242
217
<term><option>--priority <replaceable>
243
218
PRIORITY</replaceable></option></term>
283
<term><option>--no-dbus</option></term>
285
<xi:include href="mandos-options.xml" xpointer="dbus"/>
287
See also <xref linkend="dbus_interface"/>.
293
<term><option>--no-ipv6</option></term>
295
<xi:include href="mandos-options.xml" xpointer="ipv6"/>
300
<term><option>--no-restore</option></term>
302
<xi:include href="mandos-options.xml" xpointer="restore"/>
304
See also <xref linkend="persistent_state"/>.
310
<term><option>--statedir
311
<replaceable>DIRECTORY</replaceable></option></term>
313
<xi:include href="mandos-options.xml" xpointer="statedir"/>
318
<term><option>--socket
319
<replaceable>FD</replaceable></option></term>
321
<xi:include href="mandos-options.xml" xpointer="socket"/>
326
<term><option>--foreground</option></term>
328
<xi:include href="mandos-options.xml"
329
xpointer="foreground"/>
334
<term><option>--no-zeroconf</option></term>
336
<xi:include href="mandos-options.xml" xpointer="zeroconf"/>
343
259
<refsect1 id="overview">
344
260
<title>OVERVIEW</title>
345
261
<xi:include href="overview.xml"/>
347
263
This program is the server part. It is a normal server program
348
264
and will run in a normal system environment, not in an initial
349
<acronym>RAM</acronym> disk environment.
265
RAM disk environment.
353
269
<refsect1 id="protocol">
354
270
<title>NETWORK PROTOCOL</title>
362
278
start a TLS protocol handshake with a slight quirk: the Mandos
363
279
server program acts as a TLS <quote>client</quote> while the
364
280
connecting Mandos client acts as a TLS <quote>server</quote>.
365
The Mandos client must supply a TLS public key, and the key ID
366
of this public key is used by the Mandos server to look up (in a
367
list read from <filename>clients.conf</filename> at start time)
368
which binary blob to give the client. No other authentication
369
or authorization is done by the server.
281
The Mandos client must supply an OpenPGP certificate, and the
282
fingerprint of this certificate is used by the Mandos server to
283
look up (in a list read from <filename>clients.conf</filename>
284
at start time) which binary blob to give the client. No other
285
authentication or authorization is done by the server.
372
288
<title>Mandos Protocol (Version 1)</title><tgroup cols="3"><thead>
408
324
</tbody></tgroup></table>
411
327
<refsect1 id="checking">
412
328
<title>CHECKING</title>
414
330
The server will, by default, continually check that the clients
415
331
are still up. If a client has not been confirmed as being up
416
332
for some time, the client is assumed to be compromised and is no
417
longer eligible to receive the encrypted password. (Manual
418
intervention is required to re-enable a client.) The timeout,
419
extended timeout, checker program, and interval between checks
420
can be configured both globally and per client; see
421
<citerefentry><refentrytitle>mandos-clients.conf</refentrytitle>
333
longer eligible to receive the encrypted password. The timeout,
334
checker program, and interval between checks can be configured
335
both globally and per client; see <citerefentry>
336
<refentrytitle>mandos-clients.conf</refentrytitle>
422
337
<manvolnum>5</manvolnum></citerefentry>.
426
<refsect1 id="approval">
427
<title>APPROVAL</title>
429
The server can be configured to require manual approval for a
430
client before it is sent its secret. The delay to wait for such
431
approval and the default action (approve or deny) can be
432
configured both globally and per client; see <citerefentry>
433
<refentrytitle>mandos-clients.conf</refentrytitle>
434
<manvolnum>5</manvolnum></citerefentry>. By default all clients
435
will be approved immediately without delay.
438
This can be used to deny a client its secret if not manually
439
approved within a specified time. It can also be used to make
440
the server delay before giving a client its secret, allowing
441
optional manual denying of this specific client.
446
341
<refsect1 id="logging">
447
342
<title>LOGGING</title>
449
344
The server will send log message with various severity levels to
450
<filename class="devicefile">/dev/log</filename>. With the
345
<filename>/dev/log</filename>. With the
451
346
<option>--debug</option> option, it will log even more messages,
452
347
and also show them on the console.
456
<refsect1 id="persistent_state">
457
<title>PERSISTENT STATE</title>
459
Client settings, initially read from
460
<filename>clients.conf</filename>, are persistent across
461
restarts, and run-time changes will override settings in
462
<filename>clients.conf</filename>. However, if a setting is
463
<emphasis>changed</emphasis> (or a client added, or removed) in
464
<filename>clients.conf</filename>, this will take precedence.
468
<refsect1 id="dbus_interface">
469
<title>D-BUS INTERFACE</title>
471
The server will by default provide a D-Bus system bus interface.
472
This interface will only be accessible by the root user or a
473
Mandos-specific user, if such a user exists. For documentation
474
of the D-Bus API, see the file <filename>DBUS-API</filename>.
478
351
<refsect1 id="exit_status">
479
352
<title>EXIT STATUS</title>
535
<term><filename>/run/mandos.pid</filename></term>
538
The file containing the process id of the
539
<command>&COMMANDNAME;</command> process started last.
540
<emphasis >Note:</emphasis> If the <filename
541
class="directory">/run</filename> directory does not
542
exist, <filename>/var/run/mandos.pid</filename> will be
549
class="directory">/var/lib/mandos</filename></term>
552
Directory where persistent state will be saved. Change
553
this with the <option>--statedir</option> option. See
554
also the <option>--no-restore</option> option.
559
<term><filename class="devicefile">/dev/log</filename></term>
408
<term><filename>/var/run/mandos/mandos.pid</filename></term>
411
The file containing the process id of
412
<command>&COMMANDNAME;</command>.
417
<term><filename>/dev/log</filename></term>
562
420
The Unix domain socket to where local syslog messages are
585
443
backtrace. This could be considered a feature.
446
Currently, if a client is declared <quote>invalid</quote> due to
447
having timed out, the server does not record this fact onto
448
permanent storage. This has some security implications, see
449
<xref linkend="CLIENTS"/>.
452
There is currently no way of querying the server of the current
453
status of clients, other than analyzing its <systemitem
454
class="service">syslog</systemitem> output.
588
457
There is no fine-grained control over logging and debug output.
590
<xi:include href="bugs.xml"/>
460
Debug mode is conflated with running in the foreground.
463
The console log messages does not show a timestamp.
593
467
<refsect1 id="example">
603
477
<informalexample>
605
479
Run the server in debug mode, read configuration files from
606
the <filename class="directory">~/mandos</filename> directory,
607
and use the Zeroconf service name <quote>Test</quote> to not
608
collide with any other official Mandos server on this host:
480
the <filename>~/mandos</filename> directory, and use the
481
Zeroconf service name <quote>Test</quote> to not collide with
482
any other official Mandos server on this host:
628
502
</informalexample>
631
505
<refsect1 id="security">
632
506
<title>SECURITY</title>
633
<refsect2 id="server">
507
<refsect2 id="SERVER">
634
508
<title>SERVER</title>
636
510
Running this <command>&COMMANDNAME;</command> server program
637
511
should not in itself present any security risk to the host
638
computer running it. The program switches to a non-root user
512
computer running it. The program does not need any special
513
privileges to run, and is designed to run as a non-root user.
642
<refsect2 id="clients">
516
<refsect2 id="CLIENTS">
643
517
<title>CLIENTS</title>
645
519
The server only gives out its stored data to clients which
646
does have the correct key ID of the stored key ID. This is
647
guaranteed by the fact that the client sends its public key in
648
the TLS handshake; this ensures it to be genuine. The server
649
computes the key ID of the key itself and looks up the key ID
650
in its list of clients. The <filename>clients.conf</filename>
520
does have the OpenPGP key of the stored fingerprint. This is
521
guaranteed by the fact that the client sends its OpenPGP
522
public key in the TLS handshake; this ensures it to be
523
genuine. The server computes the fingerprint of the key
524
itself and looks up the fingerprint in its list of
525
clients. The <filename>clients.conf</filename> file (see
652
526
<citerefentry><refentrytitle>mandos-clients.conf</refentrytitle>
653
527
<manvolnum>5</manvolnum></citerefentry>)
654
528
<emphasis>must</emphasis> be made non-readable by anyone
655
except the user starting the server (usually root).
529
except the user running the server.
658
532
As detailed in <xref linkend="checking"/>, the status of all
660
534
compromised if they are gone for too long.
537
If a client is compromised, its downtime should be duly noted
538
by the server which would therefore declare the client
539
invalid. But if the server was ever restarted, it would
540
re-read its client list from its configuration file and again
541
regard all clients therein as valid, and hence eligible to
542
receive their passwords. Therefore, be careful when
543
restarting servers if it is suspected that a client has, in
544
fact, been compromised by parties who may now be running a
545
fake Mandos client with the keys from the non-encrypted
546
initial RAM image of the client host. What should be done in
547
that case (if restarting the server program really is
548
necessary) is to stop the server program, edit the
549
configuration file to omit any suspect clients, and restart
663
553
For more details on client-side security, see
664
<citerefentry><refentrytitle>mandos-client</refentrytitle>
554
<citerefentry><refentrytitle>password-request</refentrytitle>
665
555
<manvolnum>8mandos</manvolnum></citerefentry>.
670
560
<refsect1 id="see_also">
671
561
<title>SEE ALSO</title>
673
<citerefentry><refentrytitle>intro</refentrytitle>
674
<manvolnum>8mandos</manvolnum></citerefentry>,
675
<citerefentry><refentrytitle>mandos-clients.conf</refentrytitle>
676
<manvolnum>5</manvolnum></citerefentry>,
677
<citerefentry><refentrytitle>mandos.conf</refentrytitle>
678
<manvolnum>5</manvolnum></citerefentry>,
679
<citerefentry><refentrytitle>mandos-client</refentrytitle>
680
<manvolnum>8mandos</manvolnum></citerefentry>,
681
<citerefentry><refentrytitle>sh</refentrytitle>
682
<manvolnum>1</manvolnum></citerefentry>
564
<refentrytitle>mandos-clients.conf</refentrytitle>
565
<manvolnum>5</manvolnum></citerefentry>, <citerefentry>
566
<refentrytitle>mandos.conf</refentrytitle>
567
<manvolnum>5</manvolnum></citerefentry>, <citerefentry>
568
<refentrytitle>password-request</refentrytitle>
569
<manvolnum>8mandos</manvolnum></citerefentry>, <citerefentry>
570
<refentrytitle>sh</refentrytitle><manvolnum>1</manvolnum>
774
RFC 7250: <citetitle>Using Raw Public Keys in Transport
775
Layer Security (TLS) and Datagram Transport Layer Security
780
This is implemented by GnuTLS version 3.6.6 and is, if
781
present, used by this server so that raw public keys can be
788
RFC 6091: <citetitle>Using OpenPGP Keys for Transport Layer
789
Security (TLS) Authentication</citetitle>
793
This is implemented by GnuTLS before version 3.6.0 and is,
794
if present, used by this server so that OpenPGP keys can be
664
RFC 5081: <citetitle>Using OpenPGP Keys for Transport Layer
669
This is implemented by GnuTLS and used by this server so
670
that OpenPGP keys can be used.