68
52
<refname><command>&COMMANDNAME;</command></refname>
70
Sends encrypted passwords to authenticated Mandos clients
54
Gives encrypted passwords to authenticated Mandos clients
76
60
<command>&COMMANDNAME;</command>
77
<arg choice='opt'>--interface<arg choice='plain'>IF</arg></arg>
78
<arg choice='opt'>--address<arg choice='plain'>ADDRESS</arg></arg>
79
<arg choice='opt'>--port<arg choice='plain'>PORT</arg></arg>
80
<arg choice='opt'>--priority<arg choice='plain'>PRIORITY</arg></arg>
81
<arg choice='opt'>--servicename<arg choice='plain'>NAME</arg></arg>
82
<arg choice='opt'>--configdir<arg choice='plain'>DIRECTORY</arg></arg>
83
<arg choice='opt'>--debug</arg>
86
<command>&COMMANDNAME;</command>
87
<arg choice='opt'>-i<arg choice='plain'>IF</arg></arg>
88
<arg choice='opt'>-a<arg choice='plain'>ADDRESS</arg></arg>
89
<arg choice='opt'>-p<arg choice='plain'>PORT</arg></arg>
90
<arg choice='opt'>--priority<arg choice='plain'>PRIORITY</arg></arg>
91
<arg choice='opt'>--servicename<arg choice='plain'>NAME</arg></arg>
92
<arg choice='opt'>--configdir<arg choice='plain'>DIRECTORY</arg></arg>
93
<arg choice='opt'>--debug</arg>
96
<command>&COMMANDNAME;</command>
97
<arg choice='plain'>--help</arg>
100
<command>&COMMANDNAME;</command>
101
<arg choice='plain'>--version</arg>
104
<command>&COMMANDNAME;</command>
105
<arg choice='plain'>--check</arg>
62
<arg choice="plain"><option>--interface
63
<replaceable>NAME</replaceable></option></arg>
64
<arg choice="plain"><option>-i
65
<replaceable>NAME</replaceable></option></arg>
69
<arg choice="plain"><option>--address
70
<replaceable>ADDRESS</replaceable></option></arg>
71
<arg choice="plain"><option>-a
72
<replaceable>ADDRESS</replaceable></option></arg>
76
<arg choice="plain"><option>--port
77
<replaceable>PORT</replaceable></option></arg>
78
<arg choice="plain"><option>-p
79
<replaceable>PORT</replaceable></option></arg>
82
<arg><option>--priority
83
<replaceable>PRIORITY</replaceable></option></arg>
85
<arg><option>--servicename
86
<replaceable>NAME</replaceable></option></arg>
88
<arg><option>--configdir
89
<replaceable>DIRECTORY</replaceable></option></arg>
91
<arg><option>--debug</option></arg>
93
<arg><option>--debuglevel
94
<replaceable>LEVEL</replaceable></option></arg>
96
<arg><option>--no-dbus</option></arg>
98
<arg><option>--no-ipv6</option></arg>
100
<arg><option>--no-restore</option></arg>
102
<arg><option>--statedir
103
<replaceable>DIRECTORY</replaceable></option></arg>
105
<arg><option>--socket
106
<replaceable>FD</replaceable></option></arg>
108
<arg><option>--foreground</option></arg>
111
<command>&COMMANDNAME;</command>
113
<arg choice="plain"><option>--help</option></arg>
114
<arg choice="plain"><option>-h</option></arg>
118
<command>&COMMANDNAME;</command>
119
<arg choice="plain"><option>--version</option></arg>
122
<command>&COMMANDNAME;</command>
123
<arg choice="plain"><option>--check</option></arg>
107
125
</refsynopsisdiv>
109
127
<refsect1 id="description">
110
128
<title>DESCRIPTION</title>
112
130
<command>&COMMANDNAME;</command> is a server daemon which
113
131
handles incoming request for passwords for a pre-defined list of
114
client host computers. The Mandos server uses Zeroconf to
115
announce itself on the local network, and uses GnuTLS to
116
communicate securely with and to authenticate the clients.
117
Mandos uses IPv6 link-local addresses, since the clients are
118
assumed to not have any other addresses configured yet. Any
119
authenticated client is then given the pre-encrypted password
120
for that specific client.
132
client host computers. For an introduction, see
133
<citerefentry><refentrytitle>intro</refentrytitle>
134
<manvolnum>8mandos</manvolnum></citerefentry>. The Mandos server
135
uses Zeroconf to announce itself on the local network, and uses
136
TLS to communicate securely with and to authenticate the
137
clients. The Mandos server uses IPv6 to allow Mandos clients to
138
use IPv6 link-local addresses, since the clients will probably
139
not have any other addresses configured (see <xref
140
linkend="overview"/>). Any authenticated client is then given
141
the stored pre-encrypted password for that specific client.
125
145
<refsect1 id="purpose">
126
146
<title>PURPOSE</title>
129
148
The purpose of this is to enable <emphasis>remote and unattended
130
rebooting</emphasis> of any client host computer with an
131
<emphasis>encrypted root file system</emphasis>. The client
132
host computer should start a Mandos client in the initial RAM
133
disk environment, the Mandos client program communicates with
134
this server program to get an encrypted password, which is then
135
decrypted and used to unlock the encrypted root file system.
136
The client host computer can then continue its boot sequence
149
rebooting</emphasis> of client host computer with an
150
<emphasis>encrypted root file system</emphasis>. See <xref
151
linkend="overview"/> for details.
142
155
<refsect1 id="options">
143
156
<title>OPTIONS</title>
147
<term><literal>-h</literal>, <literal>--help</literal></term>
159
<term><option>--help</option></term>
160
<term><option>-h</option></term>
150
163
Show a help message and exit
156
<term><literal>-i</literal>, <literal>--interface <replaceable>
157
IF</replaceable></literal></term>
160
Only announce the server and listen to requests on network
161
interface <replaceable>IF</replaceable>. Default is to
162
use all available interfaces.
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
"<literal>::FFFF:192.0.2.3</literal>" syntax. Also, if a
176
link-local address is specified, an interface should be
177
set, since a link-local address is only valid on a single
178
interface. By default, the server will listen to all
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>
200
Run the server's self-tests. This includes any unit
169
<term><option>--interface</option>
170
<replaceable>NAME</replaceable></term>
171
<term><option>-i</option>
172
<replaceable>NAME</replaceable></term>
174
<xi:include href="mandos-options.xml" xpointer="interface"/>
179
<term><option>--address
180
<replaceable>ADDRESS</replaceable></option></term>
182
<replaceable>ADDRESS</replaceable></option></term>
184
<xi:include href="mandos-options.xml" xpointer="address"/>
190
<replaceable>PORT</replaceable></option></term>
192
<replaceable>PORT</replaceable></option></term>
194
<xi:include href="mandos-options.xml" xpointer="port"/>
199
<term><option>--check</option></term>
202
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
224
<citerefentry><refentrytitle>gnutls_priority_init
225
</refentrytitle><manvolnum>3</manvolnum></citerefentry>
226
for the syntax. The default is
227
"<literal>SECURE256:!CTYPE-X.509:+CTYPE-OPENPGP</literal>".
228
<emphasis>Warning</emphasis>: changing this may make the
229
TLS handshake fail, making communication with clients
236
<term><literal>--servicename <replaceable>NAME</replaceable>
240
Zeroconf service name. The default is
241
"<literal>Mandos</literal>". You only need to change this
242
if you for some reason want to run more than one server on
243
the same <emphasis>host</emphasis>. If there are name
244
collisions on the same <emphasis>network</emphasis>, the
245
new server will automatically rename itself to "Mandos
252
<term><literal>--configdir <replaceable>DIR</replaceable>
209
<term><option>--debug</option></term>
211
<xi:include href="mandos-options.xml" xpointer="debug"/>
216
<term><option>--debuglevel
217
<replaceable>LEVEL</replaceable></option></term>
220
Set the debugging log level.
221
<replaceable>LEVEL</replaceable> is a string, one of
222
<quote><literal>CRITICAL</literal></quote>,
223
<quote><literal>ERROR</literal></quote>,
224
<quote><literal>WARNING</literal></quote>,
225
<quote><literal>INFO</literal></quote>, or
226
<quote><literal>DEBUG</literal></quote>, in order of
227
increasing verbosity. The default level is
228
<quote><literal>WARNING</literal></quote>.
234
<term><option>--priority <replaceable>
235
PRIORITY</replaceable></option></term>
237
<xi:include href="mandos-options.xml"
238
xpointer="priority_compat"/>
243
<term><option>--servicename
244
<replaceable>NAME</replaceable></option></term>
246
<xi:include href="mandos-options.xml"
247
xpointer="servicename"/>
252
<term><option>--configdir
253
<replaceable>DIRECTORY</replaceable></option></term>
256
256
Directory to search for configuration files. Default is
257
"<literal>/etc/mandos</literal>". See <citerefentry>
258
<refentrytitle>mandos.conf</refentrytitle>
257
<quote><literal>/etc/mandos</literal></quote>. See
258
<citerefentry><refentrytitle>mandos.conf</refentrytitle>
259
259
<manvolnum>5</manvolnum></citerefentry> and <citerefentry>
260
260
<refentrytitle>mandos-clients.conf</refentrytitle>
261
261
<manvolnum>5</manvolnum></citerefentry>.
267
<term><literal>--version</literal></term>
267
<term><option>--version</option></term>
270
270
Prints the program version and exit.
276
<term><option>--no-dbus</option></term>
278
<xi:include href="mandos-options.xml" xpointer="dbus"/>
280
See also <xref linkend="dbus_interface"/>.
286
<term><option>--no-ipv6</option></term>
288
<xi:include href="mandos-options.xml" xpointer="ipv6"/>
293
<term><option>--no-restore</option></term>
295
<xi:include href="mandos-options.xml" xpointer="restore"/>
297
See also <xref linkend="persistent_state"/>.
303
<term><option>--statedir
304
<replaceable>DIRECTORY</replaceable></option></term>
306
<xi:include href="mandos-options.xml" xpointer="statedir"/>
311
<term><option>--socket
312
<replaceable>FD</replaceable></option></term>
314
<xi:include href="mandos-options.xml" xpointer="socket"/>
319
<term><option>--foreground</option></term>
321
<xi:include href="mandos-options.xml"
322
xpointer="foreground"/>
329
<refsect1 id="overview">
330
<title>OVERVIEW</title>
331
<xi:include href="overview.xml"/>
333
This program is the server part. It is a normal server program
334
and will run in a normal system environment, not in an initial
335
<acronym>RAM</acronym> disk environment.
277
339
<refsect1 id="protocol">
278
340
<title>NETWORK PROTOCOL</title>
280
342
The Mandos server announces itself as a Zeroconf service of type
281
"<literal>_mandos._tcp</literal>". The Mandos client connects
282
to the announced address and port, and sends a line of text
283
where the first whitespace-separated field is the protocol
284
version, which currently is "<literal>1</literal>". The client
285
and server then start a TLS protocol handshake with a slight
286
quirk: the Mandos server program acts as a TLS "client" while
287
the connecting Mandos client acts as a TLS "server". The Mandos
288
client must supply an OpenPGP certificate, and the fingerprint
289
of this certificate is used by the Mandos server to look up (in
290
a list read from a file at start time) which binary blob to give
291
the client. No other authentication or authorization is done by
343
<quote><literal>_mandos._tcp</literal></quote>. The Mandos
344
client connects to the announced address and port, and sends a
345
line of text where the first whitespace-separated field is the
346
protocol version, which currently is
347
<quote><literal>1</literal></quote>. The client and server then
348
start a TLS protocol handshake with a slight quirk: the Mandos
349
server program acts as a TLS <quote>client</quote> while the
350
connecting Mandos client acts as a TLS <quote>server</quote>.
351
The Mandos client must supply an OpenPGP certificate, and the
352
fingerprint of this certificate is used by the Mandos server to
353
look up (in a list read from <filename>clients.conf</filename>
354
at start time) which binary blob to give the client. No other
355
authentication or authorization is done by the server.
294
<informaltable><tgroup cols="3"><thead>
358
<title>Mandos Protocol (Version 1)</title><tgroup cols="3"><thead>
296
360
<entry>Mandos Client</entry>
297
361
<entry>Direction</entry>
320
386
<entry><-<!-- ← --></entry>
321
<entry>Binary blob</entry>
387
<entry>Binary blob (client will assume OpenPGP data)</entry>
325
391
<entry><-<!-- ← --></entry>
326
392
<entry>Close</entry>
328
</tbody></tgroup></informaltable>
394
</tbody></tgroup></table>
397
<refsect1 id="checking">
398
<title>CHECKING</title>
400
The server will, by default, continually check that the clients
401
are still up. If a client has not been confirmed as being up
402
for some time, the client is assumed to be compromised and is no
403
longer eligible to receive the encrypted password. (Manual
404
intervention is required to re-enable a client.) The timeout,
405
extended timeout, checker program, and interval between checks
406
can be configured both globally and per client; see
407
<citerefentry><refentrytitle>mandos-clients.conf</refentrytitle>
408
<manvolnum>5</manvolnum></citerefentry>.
412
<refsect1 id="approval">
413
<title>APPROVAL</title>
415
The server can be configured to require manual approval for a
416
client before it is sent its secret. The delay to wait for such
417
approval and the default action (approve or deny) can be
418
configured both globally and per client; see <citerefentry>
419
<refentrytitle>mandos-clients.conf</refentrytitle>
420
<manvolnum>5</manvolnum></citerefentry>. By default all clients
421
will be approved immediately without delay.
424
This can be used to deny a client its secret if not manually
425
approved within a specified time. It can also be used to make
426
the server delay before giving a client its secret, allowing
427
optional manual denying of this specific client.
331
432
<refsect1 id="logging">
332
433
<title>LOGGING</title>
334
The server will log a lot of information with various severity
336
<citerefentry><refentrytitle>syslog</refentrytitle>
337
<manvolnum>8</manvolnum></citerefentry>. With the
435
The server will send log message with various severity levels to
436
<filename class="devicefile">/dev/log</filename>. With the
338
437
<option>--debug</option> option, it will log even more messages,
339
438
and also show them on the console.
442
<refsect1 id="persistent_state">
443
<title>PERSISTENT STATE</title>
445
Client settings, initially read from
446
<filename>clients.conf</filename>, are persistent across
447
restarts, and run-time changes will override settings in
448
<filename>clients.conf</filename>. However, if a setting is
449
<emphasis>changed</emphasis> (or a client added, or removed) in
450
<filename>clients.conf</filename>, this will take precedence.
454
<refsect1 id="dbus_interface">
455
<title>D-BUS INTERFACE</title>
457
The server will by default provide a D-Bus system bus interface.
458
This interface will only be accessible by the root user or a
459
Mandos-specific user, if such a user exists. For documentation
460
of the D-Bus API, see the file <filename>DBUS-API</filename>.
343
464
<refsect1 id="exit_status">
344
465
<title>EXIT STATUS</title>
347
468
critical error is encountered.
472
<refsect1 id="environment">
473
<title>ENVIRONMENT</title>
476
<term><envar>PATH</envar></term>
479
To start the configured checker (see <xref
480
linkend="checking"/>), the server uses
481
<filename>/bin/sh</filename>, which in turn uses
482
<varname>PATH</varname> to search for matching commands if
483
an absolute path is not given. See <citerefentry>
484
<refentrytitle>sh</refentrytitle><manvolnum>1</manvolnum>
492
<refsect1 id="files">
352
493
<title>FILES</title>
356
<filename>/etc/mandos/mandos.conf</filename> See <citerefentry>
357
<refentrytitle>mandos.conf</refentrytitle>
358
<manvolnum>5</manvolnum></citerefentry>.
361
<filename>/etc/mandos/clients.conf</filename> See <citerefentry>
495
Use the <option>--configdir</option> option to change where
496
<command>&COMMANDNAME;</command> looks for its configurations
497
files. The default file names are listed here.
501
<term><filename>/etc/mandos/mandos.conf</filename></term>
504
Server-global settings. See
505
<citerefentry><refentrytitle>mandos.conf</refentrytitle>
506
<manvolnum>5</manvolnum></citerefentry> for details.
511
<term><filename>/etc/mandos/clients.conf</filename></term>
514
List of clients and client-specific settings. See
515
<citerefentry><refentrytitle>mandos-clients.conf</refentrytitle>
516
<manvolnum>5</manvolnum></citerefentry> for details.
521
<term><filename>/run/mandos.pid</filename></term>
524
The file containing the process id of the
525
<command>&COMMANDNAME;</command> process started last.
530
<term><filename class="devicefile">/dev/log</filename></term>
534
class="directory">/var/lib/mandos</filename></term>
537
Directory where persistent state will be saved. Change
538
this with the <option>--statedir</option> option. See
539
also the <option>--no-restore</option> option.
544
<term><filename>/dev/log</filename></term>
547
The Unix domain socket to where local syslog messages are
553
<term><filename>/bin/sh</filename></term>
556
This is used to start the configured checker command for
557
each client. See <citerefentry>
362
558
<refentrytitle>mandos-clients.conf</refentrytitle>
363
<manvolnum>5</manvolnum></citerefentry>.
366
<filename>/var/run/mandos/mandos.pid</filename>
559
<manvolnum>5</manvolnum></citerefentry> for details.
372
566
<refsect1 id="bugs">
373
567
<title>BUGS</title>
378
<refsect1 id="examples">
379
<title>EXAMPLES</title>
569
This server might, on especially fatal errors, emit a Python
570
backtrace. This could be considered a feature.
573
There is no fine-grained control over logging and debug output.
576
This server does not check the expire time of clients’ OpenPGP
581
<refsect1 id="example">
582
<title>EXAMPLE</title>
585
Normal invocation needs no options:
588
<userinput>&COMMANDNAME;</userinput>
593
Run the server in debug mode, read configuration files from
594
the <filename class="directory">~/mandos</filename> directory,
595
and use the Zeroconf service name <quote>Test</quote> to not
596
collide with any other official Mandos server on this host:
600
<!-- do not wrap this line -->
601
<userinput>&COMMANDNAME; --debug --configdir ~/mandos --servicename Test</userinput>
607
Run the server normally, but only listen to one interface and
608
only on the link-local address on that interface:
612
<!-- do not wrap this line -->
613
<userinput>&COMMANDNAME; --interface eth7 --address fe80::aede:48ff:fe71:f6f2</userinput>
384
619
<refsect1 id="security">
385
620
<title>SECURITY</title>
621
<refsect2 id="server">
622
<title>SERVER</title>
624
Running this <command>&COMMANDNAME;</command> server program
625
should not in itself present any security risk to the host
626
computer running it. The program switches to a non-root user
630
<refsect2 id="clients">
631
<title>CLIENTS</title>
633
The server only gives out its stored data to clients which
634
does have the OpenPGP key of the stored fingerprint. This is
635
guaranteed by the fact that the client sends its OpenPGP
636
public key in the TLS handshake; this ensures it to be
637
genuine. The server computes the fingerprint of the key
638
itself and looks up the fingerprint in its list of
639
clients. The <filename>clients.conf</filename> file (see
640
<citerefentry><refentrytitle>mandos-clients.conf</refentrytitle>
641
<manvolnum>5</manvolnum></citerefentry>)
642
<emphasis>must</emphasis> be made non-readable by anyone
643
except the user starting the server (usually root).
646
As detailed in <xref linkend="checking"/>, the status of all
647
client computers will continually be checked and be assumed
648
compromised if they are gone for too long.
651
For more details on client-side security, see
652
<citerefentry><refentrytitle>mandos-client</refentrytitle>
653
<manvolnum>8mandos</manvolnum></citerefentry>.
390
658
<refsect1 id="see_also">
391
659
<title>SEE ALSO</title>
392
<itemizedlist spacing="compact">
394
<citerefentry><refentrytitle>password-request</refentrytitle>
395
<manvolnum>8mandos</manvolnum></citerefentry>
399
<citerefentry><refentrytitle>plugin-runner</refentrytitle>
400
<manvolnum>8mandos</manvolnum></citerefentry>
404
<ulink url="http://www.zeroconf.org/">Zeroconf</ulink>
408
<ulink url="http://www.avahi.org/">Avahi</ulink>
413
url="http://www.gnu.org/software/gnutls/">GnuTLS</ulink>
417
<citation>RFC 4880: <citetitle>OpenPGP Message
418
Format</citetitle></citation>
422
<citation>RFC 5081: <citetitle>Using OpenPGP Keys for
423
Transport Layer Security</citetitle></citation>
427
<citation>RFC 4291: <citetitle>IP Version 6 Addressing
428
Architecture</citetitle>, section 2.5.6, Link-Local IPv6
429
Unicast Addresses</citation>
661
<citerefentry><refentrytitle>intro</refentrytitle>
662
<manvolnum>8mandos</manvolnum></citerefentry>,
663
<citerefentry><refentrytitle>mandos-clients.conf</refentrytitle>
664
<manvolnum>5</manvolnum></citerefentry>,
665
<citerefentry><refentrytitle>mandos.conf</refentrytitle>
666
<manvolnum>5</manvolnum></citerefentry>,
667
<citerefentry><refentrytitle>mandos-client</refentrytitle>
668
<manvolnum>8mandos</manvolnum></citerefentry>,
669
<citerefentry><refentrytitle>sh</refentrytitle>
670
<manvolnum>1</manvolnum></citerefentry>
675
<ulink url="http://www.zeroconf.org/">Zeroconf</ulink>
679
Zeroconf is the network protocol standard used by clients
680
for finding this Mandos server on the local network.
686
<ulink url="http://www.avahi.org/">Avahi</ulink>
690
Avahi is the library this server calls to implement
691
Zeroconf service announcements.
697
<ulink url="http://www.gnu.org/software/gnutls/"
702
GnuTLS is the library this server uses to implement TLS for
703
communicating securely with the client, and at the same time
704
confidently get the client’s public OpenPGP key.
710
RFC 4291: <citetitle>IP Version 6 Addressing
711
Architecture</citetitle>
716
<term>Section 2.2: <citetitle>Text Representation of
717
Addresses</citetitle></term>
718
<listitem><para/></listitem>
721
<term>Section 2.5.5.2: <citetitle>IPv4-Mapped IPv6
722
Address</citetitle></term>
723
<listitem><para/></listitem>
726
<term>Section 2.5.6, <citetitle>Link-Local IPv6 Unicast
727
Addresses</citetitle></term>
730
The clients use IPv6 link-local addresses, which are
731
immediately usable since a link-local addresses is
732
automatically assigned to a network interfaces when it
742
RFC 4346: <citetitle>The Transport Layer Security (TLS)
743
Protocol Version 1.1</citetitle>
747
TLS 1.1 is the protocol implemented by GnuTLS.
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RFC 4880: <citetitle>OpenPGP Message Format</citetitle>
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The data sent to clients is binary encrypted OpenPGP data.
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RFC 5081: <citetitle>Using OpenPGP Keys for Transport Layer
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This is implemented by GnuTLS and used by this server so
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that OpenPGP keys can be used.
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