51
68
<refname><command>&COMMANDNAME;</command></refname>
53
Gives encrypted passwords to authenticated Mandos clients
70
Sends encrypted passwords to authenticated Mandos clients
59
76
<command>&COMMANDNAME;</command>
61
<arg choice="plain"><option>--interface
62
<replaceable>NAME</replaceable></option></arg>
63
<arg choice="plain"><option>-i
64
<replaceable>NAME</replaceable></option></arg>
68
<arg choice="plain"><option>--address
69
<replaceable>ADDRESS</replaceable></option></arg>
70
<arg choice="plain"><option>-a
71
<replaceable>ADDRESS</replaceable></option></arg>
75
<arg choice="plain"><option>--port
76
<replaceable>PORT</replaceable></option></arg>
77
<arg choice="plain"><option>-p
78
<replaceable>PORT</replaceable></option></arg>
81
<arg><option>--priority
82
<replaceable>PRIORITY</replaceable></option></arg>
84
<arg><option>--servicename
85
<replaceable>NAME</replaceable></option></arg>
87
<arg><option>--configdir
88
<replaceable>DIRECTORY</replaceable></option></arg>
90
<arg><option>--debug</option></arg>
92
<arg><option>--debuglevel
93
<replaceable>LEVEL</replaceable></option></arg>
95
<arg><option>--no-dbus</option></arg>
97
<arg><option>--no-ipv6</option></arg>
99
<arg><option>--no-restore</option></arg>
101
<arg><option>--statedir
102
<replaceable>DIRECTORY</replaceable></option></arg>
104
<arg><option>--socket
105
<replaceable>FD</replaceable></option></arg>
108
<command>&COMMANDNAME;</command>
110
<arg choice="plain"><option>--help</option></arg>
111
<arg choice="plain"><option>-h</option></arg>
115
<command>&COMMANDNAME;</command>
116
<arg choice="plain"><option>--version</option></arg>
119
<command>&COMMANDNAME;</command>
120
<arg choice="plain"><option>--check</option></arg>
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>
122
107
</refsynopsisdiv>
124
109
<refsect1 id="description">
125
110
<title>DESCRIPTION</title>
127
112
<command>&COMMANDNAME;</command> is a server daemon which
128
113
handles incoming request for passwords for a pre-defined list of
129
client host computers. For an introduction, see
130
<citerefentry><refentrytitle>intro</refentrytitle>
131
<manvolnum>8mandos</manvolnum></citerefentry>. The Mandos server
132
uses Zeroconf to announce itself on the local network, and uses
133
TLS to communicate securely with and to authenticate the
134
clients. The Mandos server uses IPv6 to allow Mandos clients to
135
use IPv6 link-local addresses, since the clients will probably
136
not have any other addresses configured (see <xref
137
linkend="overview"/>). Any authenticated client is then given
138
the stored pre-encrypted password for that specific client.
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.
142
125
<refsect1 id="purpose">
143
126
<title>PURPOSE</title>
145
129
The purpose of this is to enable <emphasis>remote and unattended
146
rebooting</emphasis> of client host computer with an
147
<emphasis>encrypted root file system</emphasis>. See <xref
148
linkend="overview"/> for details.
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
152
142
<refsect1 id="options">
153
143
<title>OPTIONS</title>
156
<term><option>--help</option></term>
157
<term><option>-h</option></term>
147
<term><literal>-h</literal>, <literal>--help</literal></term>
160
150
Show a help message and exit
166
<term><option>--interface</option>
167
<replaceable>NAME</replaceable></term>
168
<term><option>-i</option>
169
<replaceable>NAME</replaceable></term>
171
<xi:include href="mandos-options.xml" xpointer="interface"/>
176
<term><option>--address
177
<replaceable>ADDRESS</replaceable></option></term>
179
<replaceable>ADDRESS</replaceable></option></term>
181
<xi:include href="mandos-options.xml" xpointer="address"/>
187
<replaceable>PORT</replaceable></option></term>
189
<replaceable>PORT</replaceable></option></term>
191
<xi:include href="mandos-options.xml" xpointer="port"/>
196
<term><option>--check</option></term>
199
Run the server’s self-tests. This includes any unit
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
206
<term><option>--debug</option></term>
208
<xi:include href="mandos-options.xml" xpointer="debug"/>
213
<term><option>--debuglevel
214
<replaceable>LEVEL</replaceable></option></term>
217
Set the debugging log level.
218
<replaceable>LEVEL</replaceable> is a string, one of
219
<quote><literal>CRITICAL</literal></quote>,
220
<quote><literal>ERROR</literal></quote>,
221
<quote><literal>WARNING</literal></quote>,
222
<quote><literal>INFO</literal></quote>, or
223
<quote><literal>DEBUG</literal></quote>, in order of
224
increasing verbosity. The default level is
225
<quote><literal>WARNING</literal></quote>.
231
<term><option>--priority <replaceable>
232
PRIORITY</replaceable></option></term>
234
<xi:include href="mandos-options.xml" xpointer="priority"/>
239
<term><option>--servicename
240
<replaceable>NAME</replaceable></option></term>
242
<xi:include href="mandos-options.xml"
243
xpointer="servicename"/>
248
<term><option>--configdir
249
<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
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>
252
256
Directory to search for configuration files. Default is
253
<quote><literal>/etc/mandos</literal></quote>. See
254
<citerefentry><refentrytitle>mandos.conf</refentrytitle>
257
"<literal>/etc/mandos</literal>". See <citerefentry>
258
<refentrytitle>mandos.conf</refentrytitle>
255
259
<manvolnum>5</manvolnum></citerefentry> and <citerefentry>
256
260
<refentrytitle>mandos-clients.conf</refentrytitle>
257
261
<manvolnum>5</manvolnum></citerefentry>.
263
<term><option>--version</option></term>
267
<term><literal>--version</literal></term>
266
270
Prints the program version and exit.
272
<term><option>--no-dbus</option></term>
274
<xi:include href="mandos-options.xml" xpointer="dbus"/>
276
See also <xref linkend="dbus_interface"/>.
282
<term><option>--no-ipv6</option></term>
284
<xi:include href="mandos-options.xml" xpointer="ipv6"/>
289
<term><option>--no-restore</option></term>
291
<xi:include href="mandos-options.xml" xpointer="restore"/>
293
See also <xref linkend="persistent_state"/>.
299
<term><option>--statedir
300
<replaceable>DIRECTORY</replaceable></option></term>
302
<xi:include href="mandos-options.xml" xpointer="statedir"/>
307
<term><option>--socket
308
<replaceable>FD</replaceable></option></term>
310
<xi:include href="mandos-options.xml" xpointer="socket"/>
317
<refsect1 id="overview">
318
<title>OVERVIEW</title>
319
<xi:include href="overview.xml"/>
321
This program is the server part. It is a normal server program
322
and will run in a normal system environment, not in an initial
323
<acronym>RAM</acronym> disk environment.
327
277
<refsect1 id="protocol">
328
278
<title>NETWORK PROTOCOL</title>
330
280
The Mandos server announces itself as a Zeroconf service of type
331
<quote><literal>_mandos._tcp</literal></quote>. The Mandos
332
client connects to the announced address and port, and sends a
333
line of text where the first whitespace-separated field is the
334
protocol version, which currently is
335
<quote><literal>1</literal></quote>. The client and server then
336
start a TLS protocol handshake with a slight quirk: the Mandos
337
server program acts as a TLS <quote>client</quote> while the
338
connecting Mandos client acts as a TLS <quote>server</quote>.
339
The Mandos client must supply an OpenPGP certificate, and the
340
fingerprint of this certificate is used by the Mandos server to
341
look up (in a list read from <filename>clients.conf</filename>
342
at start time) which binary blob to give the client. No other
343
authentication or authorization is done by the server.
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
346
<title>Mandos Protocol (Version 1)</title><tgroup cols="3"><thead>
294
<informaltable><tgroup cols="3"><thead>
348
296
<entry>Mandos Client</entry>
349
297
<entry>Direction</entry>
374
320
<entry><-<!-- ← --></entry>
375
<entry>Binary blob (client will assume OpenPGP data)</entry>
321
<entry>Binary blob</entry>
379
325
<entry><-<!-- ← --></entry>
380
326
<entry>Close</entry>
382
</tbody></tgroup></table>
385
<refsect1 id="checking">
386
<title>CHECKING</title>
388
The server will, by default, continually check that the clients
389
are still up. If a client has not been confirmed as being up
390
for some time, the client is assumed to be compromised and is no
391
longer eligible to receive the encrypted password. (Manual
392
intervention is required to re-enable a client.) The timeout,
393
extended timeout, checker program, and interval between checks
394
can be configured both globally and per client; see
395
<citerefentry><refentrytitle>mandos-clients.conf</refentrytitle>
396
<manvolnum>5</manvolnum></citerefentry>.
400
<refsect1 id="approval">
401
<title>APPROVAL</title>
403
The server can be configured to require manual approval for a
404
client before it is sent its secret. The delay to wait for such
405
approval and the default action (approve or deny) can be
406
configured both globally and per client; see <citerefentry>
407
<refentrytitle>mandos-clients.conf</refentrytitle>
408
<manvolnum>5</manvolnum></citerefentry>. By default all clients
409
will be approved immediately without delay.
412
This can be used to deny a client its secret if not manually
413
approved within a specified time. It can also be used to make
414
the server delay before giving a client its secret, allowing
415
optional manual denying of this specific client.
328
</tbody></tgroup></informaltable>
420
331
<refsect1 id="logging">
421
332
<title>LOGGING</title>
423
The server will send log message with various severity levels to
424
<filename class="devicefile">/dev/log</filename>. With the
334
The server will log a lot of information with various severity
336
<citerefentry><refentrytitle>syslog</refentrytitle>
337
<manvolnum>8</manvolnum></citerefentry>. With the
425
338
<option>--debug</option> option, it will log even more messages,
426
339
and also show them on the console.
430
<refsect1 id="persistent_state">
431
<title>PERSISTENT STATE</title>
433
Client settings, initially read from
434
<filename>clients.conf</filename>, are persistent across
435
restarts, and run-time changes will override settings in
436
<filename>clients.conf</filename>. However, if a setting is
437
<emphasis>changed</emphasis> (or a client added, or removed) in
438
<filename>clients.conf</filename>, this will take precedence.
442
<refsect1 id="dbus_interface">
443
<title>D-BUS INTERFACE</title>
445
The server will by default provide a D-Bus system bus interface.
446
This interface will only be accessible by the root user or a
447
Mandos-specific user, if such a user exists. For documentation
448
of the D-Bus API, see the file <filename>DBUS-API</filename>.
452
343
<refsect1 id="exit_status">
453
344
<title>EXIT STATUS</title>
456
347
critical error is encountered.
460
<refsect1 id="environment">
461
<title>ENVIRONMENT</title>
464
<term><envar>PATH</envar></term>
467
To start the configured checker (see <xref
468
linkend="checking"/>), the server uses
469
<filename>/bin/sh</filename>, which in turn uses
470
<varname>PATH</varname> to search for matching commands if
471
an absolute path is not given. See <citerefentry>
472
<refentrytitle>sh</refentrytitle><manvolnum>1</manvolnum>
480
<refsect1 id="files">
481
352
<title>FILES</title>
483
Use the <option>--configdir</option> option to change where
484
<command>&COMMANDNAME;</command> looks for its configurations
485
files. The default file names are listed here.
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>
362
<refentrytitle>mandos-clients.conf</refentrytitle>
363
<manvolnum>5</manvolnum></citerefentry>.
366
<filename>/var/run/mandos/mandos.pid</filename>
489
<term><filename>/etc/mandos/mandos.conf</filename></term>
492
Server-global settings. See
493
<citerefentry><refentrytitle>mandos.conf</refentrytitle>
494
<manvolnum>5</manvolnum></citerefentry> for details.
499
<term><filename>/etc/mandos/clients.conf</filename></term>
502
List of clients and client-specific settings. See
503
<citerefentry><refentrytitle>mandos-clients.conf</refentrytitle>
504
<manvolnum>5</manvolnum></citerefentry> for details.
509
<term><filename>/var/run/mandos.pid</filename></term>
512
The file containing the process id of the
513
<command>&COMMANDNAME;</command> process started last.
518
<term><filename class="devicefile">/dev/log</filename></term>
522
class="directory">/var/lib/mandos</filename></term>
525
Directory where persistent state will be saved. Change
526
this with the <option>--statedir</option> option. See
527
also the <option>--no-restore</option> option.
532
<term><filename>/dev/log</filename></term>
535
The Unix domain socket to where local syslog messages are
541
<term><filename>/bin/sh</filename></term>
544
This is used to start the configured checker command for
545
each client. See <citerefentry>
546
<refentrytitle>mandos-clients.conf</refentrytitle>
547
<manvolnum>5</manvolnum></citerefentry> for details.
554
372
<refsect1 id="bugs">
555
373
<title>BUGS</title>
557
This server might, on especially fatal errors, emit a Python
558
backtrace. This could be considered a feature.
561
There is no fine-grained control over logging and debug output.
564
Debug mode is conflated with running in the foreground.
567
This server does not check the expire time of clients’ OpenPGP
572
<refsect1 id="example">
573
<title>EXAMPLE</title>
576
Normal invocation needs no options:
579
<userinput>&COMMANDNAME;</userinput>
584
Run the server in debug mode, read configuration files from
585
the <filename class="directory">~/mandos</filename> directory,
586
and use the Zeroconf service name <quote>Test</quote> to not
587
collide with any other official Mandos server on this host:
591
<!-- do not wrap this line -->
592
<userinput>&COMMANDNAME; --debug --configdir ~/mandos --servicename Test</userinput>
598
Run the server normally, but only listen to one interface and
599
only on the link-local address on that interface:
603
<!-- do not wrap this line -->
604
<userinput>&COMMANDNAME; --interface eth7 --address fe80::aede:48ff:fe71:f6f2</userinput>
378
<refsect1 id="examples">
379
<title>EXAMPLES</title>
610
384
<refsect1 id="security">
611
385
<title>SECURITY</title>
612
<refsect2 id="server">
613
<title>SERVER</title>
615
Running this <command>&COMMANDNAME;</command> server program
616
should not in itself present any security risk to the host
617
computer running it. The program switches to a non-root user
621
<refsect2 id="clients">
622
<title>CLIENTS</title>
624
The server only gives out its stored data to clients which
625
does have the OpenPGP key of the stored fingerprint. This is
626
guaranteed by the fact that the client sends its OpenPGP
627
public key in the TLS handshake; this ensures it to be
628
genuine. The server computes the fingerprint of the key
629
itself and looks up the fingerprint in its list of
630
clients. The <filename>clients.conf</filename> file (see
631
<citerefentry><refentrytitle>mandos-clients.conf</refentrytitle>
632
<manvolnum>5</manvolnum></citerefentry>)
633
<emphasis>must</emphasis> be made non-readable by anyone
634
except the user starting the server (usually root).
637
As detailed in <xref linkend="checking"/>, the status of all
638
client computers will continually be checked and be assumed
639
compromised if they are gone for too long.
642
For more details on client-side security, see
643
<citerefentry><refentrytitle>mandos-client</refentrytitle>
644
<manvolnum>8mandos</manvolnum></citerefentry>.
649
390
<refsect1 id="see_also">
650
391
<title>SEE ALSO</title>
652
<citerefentry><refentrytitle>intro</refentrytitle>
653
<manvolnum>8mandos</manvolnum></citerefentry>,
654
<citerefentry><refentrytitle>mandos-clients.conf</refentrytitle>
655
<manvolnum>5</manvolnum></citerefentry>,
656
<citerefentry><refentrytitle>mandos.conf</refentrytitle>
657
<manvolnum>5</manvolnum></citerefentry>,
658
<citerefentry><refentrytitle>mandos-client</refentrytitle>
659
<manvolnum>8mandos</manvolnum></citerefentry>,
660
<citerefentry><refentrytitle>sh</refentrytitle>
661
<manvolnum>1</manvolnum></citerefentry>
666
<ulink url="http://www.zeroconf.org/">Zeroconf</ulink>
670
Zeroconf is the network protocol standard used by clients
671
for finding this Mandos server on the local network.
677
<ulink url="http://www.avahi.org/">Avahi</ulink>
681
Avahi is the library this server calls to implement
682
Zeroconf service announcements.
688
<ulink url="http://www.gnu.org/software/gnutls/"
693
GnuTLS is the library this server uses to implement TLS for
694
communicating securely with the client, and at the same time
695
confidently get the client’s public OpenPGP key.
701
RFC 4291: <citetitle>IP Version 6 Addressing
702
Architecture</citetitle>
707
<term>Section 2.2: <citetitle>Text Representation of
708
Addresses</citetitle></term>
709
<listitem><para/></listitem>
712
<term>Section 2.5.5.2: <citetitle>IPv4-Mapped IPv6
713
Address</citetitle></term>
714
<listitem><para/></listitem>
717
<term>Section 2.5.6, <citetitle>Link-Local IPv6 Unicast
718
Addresses</citetitle></term>
721
The clients use IPv6 link-local addresses, which are
722
immediately usable since a link-local addresses is
723
automatically assigned to a network interfaces when it
733
RFC 4346: <citetitle>The Transport Layer Security (TLS)
734
Protocol Version 1.1</citetitle>
738
TLS 1.1 is the protocol implemented by GnuTLS.
744
RFC 4880: <citetitle>OpenPGP Message Format</citetitle>
748
The data sent to clients is binary encrypted OpenPGP data.
754
RFC 5081: <citetitle>Using OpenPGP Keys for Transport Layer
759
This is implemented by GnuTLS and used by this server so
760
that OpenPGP keys can be used.
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
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Architecture</citetitle>, section 2.5.6, Link-Local IPv6
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Unicast Addresses</citation>
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