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 "2019-02-10">
6
<!ENTITY % common SYSTEM "common.ent">
6
<!ENTITY OVERVIEW SYSTEM "overview.xml">
10
<refentry xmlns:xi="http://www.w3.org/2001/XInclude">
12
<title>Mandos Manual</title>
11
<title>&COMMANDNAME;</title>
13
12
<!-- NWalsh’s docbook scripts use this to generate the footer: -->
14
<productname>Mandos</productname>
15
<productnumber>&version;</productnumber>
16
<date>&TIMESTAMP;</date>
13
<productname>&COMMANDNAME;</productname>
14
<productnumber>&VERSION;</productnumber>
19
17
<firstname>Björn</firstname>
20
18
<surname>Påhlsson</surname>
22
<email>belorn@recompile.se</email>
20
<email>belorn@fukt.bsnet.se</email>
26
24
<firstname>Teddy</firstname>
27
25
<surname>Hogeborn</surname>
29
<email>teddy@recompile.se</email>
27
<email>teddy@fukt.bsnet.se</email>
46
33
<holder>Teddy Hogeborn</holder>
47
34
<holder>Björn Påhlsson</holder>
49
<xi:include href="legalnotice.xml"/>
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/"/>.
53
62
<refentrytitle>&COMMANDNAME;</refentrytitle>
54
63
<manvolnum>8</manvolnum>
58
67
<refname><command>&COMMANDNAME;</command></refname>
60
Gives encrypted passwords to authenticated Mandos clients
69
Sends encrypted passwords to authenticated Mandos clients
66
75
<command>&COMMANDNAME;</command>
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>
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>
119
95
<command>&COMMANDNAME;</command>
120
96
<group choice="req">
121
<arg choice="plain"><option>--help</option></arg>
122
<arg choice="plain"><option>-h</option></arg>
97
<arg choice="plain">-h</arg>
98
<arg choice="plain">--help</arg>
126
102
<command>&COMMANDNAME;</command>
127
<arg choice="plain"><option>--version</option></arg>
103
<arg choice="plain">--version</arg>
130
106
<command>&COMMANDNAME;</command>
131
<arg choice="plain"><option>--check</option></arg>
107
<arg choice="plain">--check</arg>
133
109
</refsynopsisdiv>
135
111
<refsect1 id="description">
136
112
<title>DESCRIPTION</title>
138
114
<command>&COMMANDNAME;</command> is a server daemon which
139
115
handles incoming request for passwords for a pre-defined list of
140
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.
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.
153
128
<refsect1 id="purpose">
154
129
<title>PURPOSE</title>
156
132
The purpose of this is to enable <emphasis>remote and unattended
157
133
rebooting</emphasis> of client host computer with an
158
134
<emphasis>encrypted root file system</emphasis>. See <xref
159
135
linkend="overview"/> for details.
163
140
<refsect1 id="options">
164
141
<title>OPTIONS</title>
167
<term><option>--help</option></term>
168
<term><option>-h</option></term>
145
<term><literal>-h</literal>, <literal>--help</literal></term>
171
148
Show a help message and exit
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>
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>
210
200
Run the server’s self-tests. This includes any unit
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>
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>
263
257
Directory to search for configuration files. Default is
274
<term><option>--version</option></term>
268
<term><literal>--version</literal></term>
277
271
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"/>
343
278
<refsect1 id="overview">
344
279
<title>OVERVIEW</title>
345
<xi:include href="overview.xml"/>
347
282
This program is the server part. It is a normal server program
348
283
and will run in a normal system environment, not in an initial
349
<acronym>RAM</acronym> disk environment.
284
RAM disk environment.
353
288
<refsect1 id="protocol">
354
289
<title>NETWORK PROTOCOL</title>
408
343
</tbody></tgroup></table>
411
346
<refsect1 id="checking">
412
347
<title>CHECKING</title>
414
349
The server will, by default, continually check that the clients
415
350
are still up. If a client has not been confirmed as being up
416
351
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>
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>
357
<refentrytitle>mandos-clients.conf</refentrytitle>
422
358
<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
362
<refsect1 id="logging">
447
363
<title>LOGGING</title>
449
The server will send log message with various severity levels to
450
<filename class="devicefile">/dev/log</filename>. With the
365
The server will send log messaged with various severity levels
366
to <filename>/dev/log</filename>. With the
451
367
<option>--debug</option> option, it will log even more messages,
452
368
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
372
<refsect1 id="exit_status">
479
373
<title>EXIT STATUS</title>
624
519
<!-- do not wrap this line -->
625
<userinput>&COMMANDNAME; --interface eth7 --address fe80::aede:48ff:fe71:f6f2</userinput>
520
<userinput>mandos --interface eth7 --address fe80::aede:48ff:fe71:f6f2</userinput>
628
523
</informalexample>
631
526
<refsect1 id="security">
632
527
<title>SECURITY</title>
633
<refsect2 id="server">
528
<refsect2 id="SERVER">
634
529
<title>SERVER</title>
636
531
Running this <command>&COMMANDNAME;</command> server program
637
532
should not in itself present any security risk to the host
638
computer running it. The program switches to a non-root user
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.
642
<refsect2 id="clients">
537
<refsect2 id="CLIENTS">
643
538
<title>CLIENTS</title>
645
540
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>
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
652
547
<citerefentry><refentrytitle>mandos-clients.conf</refentrytitle>
653
548
<manvolnum>5</manvolnum></citerefentry>)
654
549
<emphasis>must</emphasis> be made non-readable by anyone
655
except the user starting the server (usually root).
550
except the user running the server.
658
553
As detailed in <xref linkend="checking"/>, the status of all
660
555
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.
663
573
For more details on client-side security, see
664
<citerefentry><refentrytitle>mandos-client</refentrytitle>
574
<citerefentry><refentrytitle>password-request</refentrytitle>
665
575
<manvolnum>8mandos</manvolnum></citerefentry>.
670
580
<refsect1 id="see_also">
671
581
<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.
687
601
<ulink url="http://www.zeroconf.org/">Zeroconf</ulink>
709
<ulink url="https://gnutls.org/">GnuTLS</ulink>
624
url="http://www.gnu.org/software/gnutls/">GnuTLS</ulink>
713
628
GnuTLS is the library this server uses to implement TLS for
714
629
communicating securely with the client, and at the same time
715
confidently get the client’s public key.
630
confidently get the client’s public OpenPGP key.
721
RFC 4291: <citetitle>IP Version 6 Addressing
722
Architecture</citetitle>
636
<citation>RFC 4291: <citetitle>IP Version 6 Addressing
637
Architecture</citetitle>, section 2.5.6, Link-Local IPv6
638
Unicast Addresses</citation>
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 addresses is
743
automatically assigned to a network interfaces when it
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
753
RFC 5246: <citetitle>The Transport Layer Security (TLS)
754
Protocol Version 1.2</citetitle>
651
<citation>RFC 4346: <citetitle>The Transport Layer Security
652
(TLS) Protocol Version 1.1</citetitle></citation>
758
TLS 1.2 is the protocol implemented by GnuTLS.
656
TLS 1.1 is the protocol implemented by GnuTLS.
764
RFC 4880: <citetitle>OpenPGP Message Format</citetitle>
662
<citation>RFC 4880: <citetitle>OpenPGP Message
663
Format</citetitle></citation>