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">
5
4
<!ENTITY COMMANDNAME "mandos">
6
<!ENTITY OVERVIEW SYSTEM "overview.xml">
5
<!ENTITY TIMESTAMP "2022-04-24">
6
<!ENTITY % common SYSTEM "common.ent">
11
<title>&COMMANDNAME;</title>
10
<refentry xmlns:xi="http://www.w3.org/2001/XInclude">
12
<title>Mandos Manual</title>
12
13
<!-- NWalsh’s docbook scripts use this to generate the footer: -->
13
<productname>&COMMANDNAME;</productname>
14
<productnumber>&VERSION;</productnumber>
14
<productname>Mandos</productname>
15
<productnumber>&version;</productnumber>
16
<date>&TIMESTAMP;</date>
17
19
<firstname>Björn</firstname>
18
20
<surname>Påhlsson</surname>
20
<email>belorn@fukt.bsnet.se</email>
22
<email>belorn@recompile.se</email>
24
26
<firstname>Teddy</firstname>
25
27
<surname>Hogeborn</surname>
27
<email>teddy@fukt.bsnet.se</email>
29
<email>teddy@recompile.se</email>
33
46
<holder>Teddy Hogeborn</holder>
34
47
<holder>Björn Påhlsson</holder>
38
This manual page is free software: you can redistribute it
39
and/or modify it under the terms of the GNU General Public
40
License as published by the Free Software Foundation,
41
either version 3 of the License, or (at your option) any
46
This manual page is distributed in the hope that it will
47
be useful, but WITHOUT ANY WARRANTY; without even the
48
implied warranty of MERCHANTABILITY or FITNESS FOR A
49
PARTICULAR PURPOSE. See the GNU General Public License
54
You should have received a copy of the GNU General Public
55
License along with this program; If not, see
56
<ulink url="http://www.gnu.org/licenses/"/>.
49
<xi:include href="legalnotice.xml"/>
62
53
<refentrytitle>&COMMANDNAME;</refentrytitle>
63
54
<manvolnum>8</manvolnum>
67
58
<refname><command>&COMMANDNAME;</command></refname>
69
Sends encrypted passwords to authenticated Mandos clients
60
Gives encrypted passwords to authenticated Mandos clients
75
66
<command>&COMMANDNAME;</command>
76
<arg>--interface<arg choice="plain">IF</arg></arg>
77
<arg>--address<arg choice="plain">ADDRESS</arg></arg>
78
<arg>--port<arg choice="plain">PORT</arg></arg>
79
<arg>--priority<arg choice="plain">PRIORITY</arg></arg>
80
<arg>--servicename<arg choice="plain">NAME</arg></arg>
81
<arg>--configdir<arg choice="plain">DIRECTORY</arg></arg>
85
<command>&COMMANDNAME;</command>
86
<arg>-i<arg choice="plain">IF</arg></arg>
87
<arg>-a<arg choice="plain">ADDRESS</arg></arg>
88
<arg>-p<arg choice="plain">PORT</arg></arg>
89
<arg>--priority<arg choice="plain">PRIORITY</arg></arg>
90
<arg>--servicename<arg choice="plain">NAME</arg></arg>
91
<arg>--configdir<arg choice="plain">DIRECTORY</arg></arg>
68
<arg choice="plain"><option>--interface
69
<replaceable>NAME</replaceable></option></arg>
70
<arg choice="plain"><option>-i
71
<replaceable>NAME</replaceable></option></arg>
75
<arg choice="plain"><option>--address
76
<replaceable>ADDRESS</replaceable></option></arg>
77
<arg choice="plain"><option>-a
78
<replaceable>ADDRESS</replaceable></option></arg>
82
<arg choice="plain"><option>--port
83
<replaceable>PORT</replaceable></option></arg>
84
<arg choice="plain"><option>-p
85
<replaceable>PORT</replaceable></option></arg>
88
<arg><option>--priority
89
<replaceable>PRIORITY</replaceable></option></arg>
91
<arg><option>--servicename
92
<replaceable>NAME</replaceable></option></arg>
94
<arg><option>--configdir
95
<replaceable>DIRECTORY</replaceable></option></arg>
97
<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>
95
119
<command>&COMMANDNAME;</command>
96
120
<group choice="req">
97
<arg choice="plain">-h</arg>
98
<arg choice="plain">--help</arg>
121
<arg choice="plain"><option>--help</option></arg>
122
<arg choice="plain"><option>-h</option></arg>
102
126
<command>&COMMANDNAME;</command>
103
<arg choice="plain">--version</arg>
127
<arg choice="plain"><option>--version</option></arg>
106
130
<command>&COMMANDNAME;</command>
107
<arg choice="plain">--check</arg>
131
<arg choice="plain"><option>--check</option></arg>
109
133
</refsynopsisdiv>
111
135
<refsect1 id="description">
112
136
<title>DESCRIPTION</title>
114
138
<command>&COMMANDNAME;</command> is a server daemon which
115
handles incoming request for passwords for a pre-defined list of
116
client host computers. The Mandos server uses Zeroconf to
117
announce itself on the local network, and uses TLS to
118
communicate securely with and to authenticate the clients. The
119
Mandos server uses IPv6 to allow Mandos clients to use IPv6
120
link-local addresses, since the clients will probably not have
121
any other addresses configured (see <xref linkend="overview"/>).
122
Any authenticated client is then given the stored pre-encrypted
123
password for that specific client.
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.
128
153
<refsect1 id="purpose">
129
154
<title>PURPOSE</title>
132
156
The purpose of this is to enable <emphasis>remote and unattended
133
157
rebooting</emphasis> of client host computer with an
134
158
<emphasis>encrypted root file system</emphasis>. See <xref
135
159
linkend="overview"/> for details.
140
163
<refsect1 id="options">
141
164
<title>OPTIONS</title>
145
<term><literal>-h</literal>, <literal>--help</literal></term>
167
<term><option>--help</option></term>
168
<term><option>-h</option></term>
148
171
Show a help message and exit
154
<term><literal>-i</literal>, <literal>--interface <replaceable>
155
IF</replaceable></literal></term>
158
Only announce the server and listen to requests on network
159
interface <replaceable>IF</replaceable>. Default is to
160
use all available interfaces. <emphasis>Note:</emphasis>
161
a failure to bind to the specified interface is not
162
considered critical, and the server does not exit.
168
<term><literal>-a</literal>, <literal>--address <replaceable>
169
ADDRESS</replaceable></literal></term>
172
If this option is used, the server will only listen to a
173
specific address. This must currently be an IPv6 address;
174
an IPv4 address can be specified using the
175
<quote><literal>::FFFF:192.0.2.3</literal></quote> syntax.
176
Also, if a link-local address is specified, an interface
177
should be set, since a link-local address is only valid on
178
a single interface. By default, the server will listen to
179
all available addresses.
185
<term><literal>-p</literal>, <literal>--port <replaceable>
186
PORT</replaceable></literal></term>
189
If this option is used, the server to bind to that
190
port. By default, the server will listen to an arbitrary
191
port given by the operating system.
197
<term><literal>--check</literal></term>
177
<term><option>--interface</option>
178
<replaceable>NAME</replaceable></term>
179
<term><option>-i</option>
180
<replaceable>NAME</replaceable></term>
182
<xi:include href="mandos-options.xml" xpointer="interface"/>
187
<term><option>--address
188
<replaceable>ADDRESS</replaceable></option></term>
190
<replaceable>ADDRESS</replaceable></option></term>
192
<xi:include href="mandos-options.xml" xpointer="address"/>
198
<replaceable>PORT</replaceable></option></term>
200
<replaceable>PORT</replaceable></option></term>
202
<xi:include href="mandos-options.xml" xpointer="port"/>
207
<term><option>--check</option></term>
200
210
Run the server’s self-tests. This includes any unit
207
<term><literal>--debug</literal></term>
210
If the server is run in debug mode, it will run in the
211
foreground and print a lot of debugging information. The
212
default is <emphasis>not</emphasis> to run in debug mode.
218
<term><literal>--priority <replaceable>
219
PRIORITY</replaceable></literal></term>
222
GnuTLS priority string for the TLS handshake with the
223
clients. The default is
224
<quote><literal>SECURE256:!CTYPE-X.509:+CTYPE-OPENPGP</literal></quote>.
225
See <citerefentry><refentrytitle>gnutls_priority_init
226
</refentrytitle><manvolnum>3</manvolnum></citerefentry>
227
for the syntax. <emphasis>Warning</emphasis>: changing
228
this may make the TLS handshake fail, making communication
229
with clients impossible.
235
<term><literal>--servicename <replaceable>NAME</replaceable>
239
Zeroconf service name. The default is
240
<quote><literal>Mandos</literal></quote>. You only need
241
to change this if you for some reason want to run more
242
than one server on the same <emphasis>host</emphasis>,
243
which would not normally be useful. If there are name
244
collisions on the same <emphasis>network</emphasis>, the
245
newer server will automatically rename itself to
246
<quote><literal>Mandos #2</literal></quote>, and so on;
247
therefore, this option is not needed in that case.
253
<term><literal>--configdir <replaceable>DIR</replaceable>
217
<term><option>--debug</option></term>
219
<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
<term><option>--priority <replaceable>
243
PRIORITY</replaceable></option></term>
245
<xi:include href="mandos-options.xml" xpointer="priority"/>
250
<term><option>--servicename
251
<replaceable>NAME</replaceable></option></term>
253
<xi:include href="mandos-options.xml"
254
xpointer="servicename"/>
259
<term><option>--configdir
260
<replaceable>DIRECTORY</replaceable></option></term>
257
263
Directory to search for configuration files. Default is
268
<term><literal>--version</literal></term>
274
<term><option>--version</option></term>
271
277
Prints the program version and exit.
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"/>
278
343
<refsect1 id="overview">
279
344
<title>OVERVIEW</title>
345
<xi:include href="overview.xml"/>
282
347
This program is the server part. It is a normal server program
283
348
and will run in a normal system environment, not in an initial
284
RAM disk environment.
349
<acronym>RAM</acronym> disk environment.
288
353
<refsect1 id="protocol">
289
354
<title>NETWORK PROTOCOL</title>
343
408
</tbody></tgroup></table>
346
411
<refsect1 id="checking">
347
412
<title>CHECKING</title>
349
414
The server will, by default, continually check that the clients
350
415
are still up. If a client has not been confirmed as being up
351
416
for some time, the client is assumed to be compromised and is no
352
longer eligible to receive the encrypted password. The timeout,
353
checker program, and interval between checks can be configured
354
both globally and per client; see <citerefentry>
355
<refentrytitle>mandos.conf</refentrytitle>
356
<manvolnum>5</manvolnum></citerefentry> and <citerefentry>
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>
422
<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>
357
433
<refentrytitle>mandos-clients.conf</refentrytitle>
358
<manvolnum>5</manvolnum></citerefentry>.
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.
362
446
<refsect1 id="logging">
363
447
<title>LOGGING</title>
365
The server will send log messaged with various severity levels
366
to <filename>/dev/log</filename>. With the
449
The server will send log message with various severity levels to
450
<filename class="devicefile">/dev/log</filename>. With the
367
451
<option>--debug</option> option, it will log even more messages,
368
452
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>.
372
478
<refsect1 id="exit_status">
373
479
<title>EXIT STATUS</title>
519
624
<!-- do not wrap this line -->
520
<userinput>mandos --interface eth7 --address fe80::aede:48ff:fe71:f6f2</userinput>
625
<userinput>&COMMANDNAME; --interface eth7 --address fe80::aede:48ff:fe71:f6f2</userinput>
523
628
</informalexample>
526
631
<refsect1 id="security">
527
632
<title>SECURITY</title>
528
<refsect2 id="SERVER">
633
<refsect2 id="server">
529
634
<title>SERVER</title>
531
636
Running this <command>&COMMANDNAME;</command> server program
532
637
should not in itself present any security risk to the host
533
computer running it. The program does not need any special
534
privileges to run, and is designed to run as a non-root user.
638
computer running it. The program switches to a non-root user
537
<refsect2 id="CLIENTS">
642
<refsect2 id="clients">
538
643
<title>CLIENTS</title>
540
645
The server only gives out its stored data to clients which
541
does have the OpenPGP key of the stored fingerprint. This is
542
guaranteed by the fact that the client sends its OpenPGP
543
public key in the TLS handshake; this ensures it to be
544
genuine. The server computes the fingerprint of the key
545
itself and looks up the fingerprint in its list of
546
clients. The <filename>clients.conf</filename> file (see
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>
547
652
<citerefentry><refentrytitle>mandos-clients.conf</refentrytitle>
548
653
<manvolnum>5</manvolnum></citerefentry>)
549
654
<emphasis>must</emphasis> be made non-readable by anyone
550
except the user running the server.
655
except the user starting the server (usually root).
553
658
As detailed in <xref linkend="checking"/>, the status of all
555
660
compromised if they are gone for too long.
558
If a client is compromised, its downtime should be duly noted
559
by the server which would therefore declare the client
560
invalid. But if the server was ever restarted, it would
561
re-read its client list from its configuration file and again
562
regard all clients therein as valid, and hence eligible to
563
receive their passwords. Therefore, be careful when
564
restarting servers if you suspect that a client has, in fact,
565
been compromised by parties who may now be running a fake
566
Mandos client with the keys from the non-encrypted initial RAM
567
image of the client host. What should be done in that case
568
(if restarting the server program really is necessary) is to
569
stop the server program, edit the configuration file to omit
570
any suspect clients, and restart the server program.
573
663
For more details on client-side security, see
574
<citerefentry><refentrytitle>password-request</refentrytitle>
664
<citerefentry><refentrytitle>mandos-client</refentrytitle>
575
665
<manvolnum>8mandos</manvolnum></citerefentry>.
580
670
<refsect1 id="see_also">
581
671
<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>
586
<refentrytitle>password-request</refentrytitle>
587
<manvolnum>8mandos</manvolnum>
592
This is the actual program which talks to this server.
593
Note that it is normally not invoked directly, and is only
594
run in the initial RAM disk environment, and not on a
595
fully started system.
601
687
<ulink url="http://www.zeroconf.org/">Zeroconf</ulink>
624
url="http://www.gnu.org/software/gnutls/">GnuTLS</ulink>
709
<ulink url="https://gnutls.org/">GnuTLS</ulink>
628
713
GnuTLS is the library this server uses to implement TLS for
629
714
communicating securely with the client, and at the same time
630
confidently get the client’s public OpenPGP key.
715
confidently get the client’s public key.
636
<citation>RFC 4291: <citetitle>IP Version 6 Addressing
637
Architecture</citetitle>, section 2.5.6, Link-Local IPv6
638
Unicast Addresses</citation>
721
RFC 4291: <citetitle>IP Version 6 Addressing
722
Architecture</citetitle>
642
The clients use IPv6 link-local addresses, which are
643
immediately usable since a link-local addresses is
644
automatically assigned to a network interfaces when it is
727
<term>Section 2.2: <citetitle>Text Representation of
728
Addresses</citetitle></term>
729
<listitem><para/></listitem>
732
<term>Section 2.5.5.2: <citetitle>IPv4-Mapped IPv6
733
Address</citetitle></term>
734
<listitem><para/></listitem>
737
<term>Section 2.5.6, <citetitle>Link-Local IPv6 Unicast
738
Addresses</citetitle></term>
741
The clients use IPv6 link-local addresses, which are
742
immediately usable since a link-local address is
743
automatically assigned to a network interfaces when it
651
<citation>RFC 4346: <citetitle>The Transport Layer Security
652
(TLS) Protocol Version 1.1</citetitle></citation>
753
RFC 5246: <citetitle>The Transport Layer Security (TLS)
754
Protocol Version 1.2</citetitle>
656
TLS 1.1 is the protocol implemented by GnuTLS.
758
TLS 1.2 is the protocol implemented by GnuTLS.
662
<citation>RFC 4880: <citetitle>OpenPGP Message
663
Format</citetitle></citation>
764
RFC 4880: <citetitle>OpenPGP Message Format</citetitle>