67
51
<refname><command>&COMMANDNAME;</command></refname>
69
Sends encrypted passwords to authenticated mandos clients
53
Gives encrypted passwords to authenticated Mandos clients
75
59
<command>&COMMANDNAME;</command>
76
<arg choice='opt' rep='repeat'>OPTION</arg>
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>
105
<command>&COMMANDNAME;</command>
107
<arg choice="plain"><option>--help</option></arg>
108
<arg choice="plain"><option>-h</option></arg>
112
<command>&COMMANDNAME;</command>
113
<arg choice="plain"><option>--version</option></arg>
116
<command>&COMMANDNAME;</command>
117
<arg choice="plain"><option>--check</option></arg>
80
121
<refsect1 id="description">
81
122
<title>DESCRIPTION</title>
83
<command>&COMMANDNAME;</command> is a server daemon that handels
84
incomming passwords request for passwords. Mandos use avahi to
85
announce the service, and through gnutls authenticates
86
clients. Any authenticated client is then given its encrypted
92
<term><literal>-h</literal>, <literal>--help</literal></term>
95
show a help message and exit
101
<term><literal>-i</literal>, <literal>--interface <replaceable>
102
IF</replaceable></literal></term>
111
<term><literal>-a</literal>, <literal>--address <replaceable>
112
ADDRESS</replaceable></literal></term>
115
Address to listen for requests on
121
<term><literal>-p</literal>, <literal>--port <replaceable>
122
PORT</replaceable></literal></term>
125
Port number to receive requests on
131
<term><literal>--check</literal></term>
134
Run self-test on the server
140
<term><literal>--debug</literal></term>
149
<term><literal>--priority <replaceable>
150
PRIORITY</replaceable></literal></term>
153
GnuTLS priority string. See <citerefentry>
154
<refentrytitle>gnutls_priority_init</refentrytitle>
155
<manvolnum>3</manvolnum></citerefentry>
161
<term><literal>--servicename <replaceable>NAME</replaceable>
165
Zeroconf service name
171
<term><literal>--configdir <replaceable>DIR</replaceable>
175
Directory to search for configuration files
124
<command>&COMMANDNAME;</command> is a server daemon which
125
handles incoming request for passwords for a pre-defined list of
126
client host computers. For an introduction, see
127
<citerefentry><refentrytitle>intro</refentrytitle>
128
<manvolnum>8mandos</manvolnum></citerefentry>. The Mandos server
129
uses Zeroconf to announce itself on the local network, and uses
130
TLS to communicate securely with and to authenticate the
131
clients. The Mandos server uses IPv6 to allow Mandos clients to
132
use IPv6 link-local addresses, since the clients will probably
133
not have any other addresses configured (see <xref
134
linkend="overview"/>). Any authenticated client is then given
135
the stored pre-encrypted password for that specific client.
139
<refsect1 id="purpose">
140
<title>PURPOSE</title>
142
The purpose of this is to enable <emphasis>remote and unattended
143
rebooting</emphasis> of client host computer with an
144
<emphasis>encrypted root file system</emphasis>. See <xref
145
linkend="overview"/> for details.
149
<refsect1 id="options">
150
<title>OPTIONS</title>
153
<term><option>--help</option></term>
154
<term><option>-h</option></term>
157
Show a help message and exit
163
<term><option>--interface</option>
164
<replaceable>NAME</replaceable></term>
165
<term><option>-i</option>
166
<replaceable>NAME</replaceable></term>
168
<xi:include href="mandos-options.xml" xpointer="interface"/>
173
<term><option>--address
174
<replaceable>ADDRESS</replaceable></option></term>
176
<replaceable>ADDRESS</replaceable></option></term>
178
<xi:include href="mandos-options.xml" xpointer="address"/>
184
<replaceable>PORT</replaceable></option></term>
186
<replaceable>PORT</replaceable></option></term>
188
<xi:include href="mandos-options.xml" xpointer="port"/>
193
<term><option>--check</option></term>
196
Run the server’s self-tests. This includes any unit
203
<term><option>--debug</option></term>
205
<xi:include href="mandos-options.xml" xpointer="debug"/>
210
<term><option>--debuglevel
211
<replaceable>LEVEL</replaceable></option></term>
214
Set the debugging log level.
215
<replaceable>LEVEL</replaceable> is a string, one of
216
<quote><literal>CRITICAL</literal></quote>,
217
<quote><literal>ERROR</literal></quote>,
218
<quote><literal>WARNING</literal></quote>,
219
<quote><literal>INFO</literal></quote>, or
220
<quote><literal>DEBUG</literal></quote>, in order of
221
increasing verbosity. The default level is
222
<quote><literal>WARNING</literal></quote>.
228
<term><option>--priority <replaceable>
229
PRIORITY</replaceable></option></term>
231
<xi:include href="mandos-options.xml" xpointer="priority"/>
236
<term><option>--servicename
237
<replaceable>NAME</replaceable></option></term>
239
<xi:include href="mandos-options.xml"
240
xpointer="servicename"/>
245
<term><option>--configdir
246
<replaceable>DIRECTORY</replaceable></option></term>
249
Directory to search for configuration files. Default is
250
<quote><literal>/etc/mandos</literal></quote>. See
251
<citerefentry><refentrytitle>mandos.conf</refentrytitle>
252
<manvolnum>5</manvolnum></citerefentry> and <citerefentry>
253
<refentrytitle>mandos-clients.conf</refentrytitle>
254
<manvolnum>5</manvolnum></citerefentry>.
260
<term><option>--version</option></term>
263
Prints the program version and exit.
269
<term><option>--no-dbus</option></term>
271
<xi:include href="mandos-options.xml" xpointer="dbus"/>
273
See also <xref linkend="dbus_interface"/>.
279
<term><option>--no-ipv6</option></term>
281
<xi:include href="mandos-options.xml" xpointer="ipv6"/>
286
<term><option>--no-restore</option></term>
288
<xi:include href="mandos-options.xml" xpointer="restore"/>
290
See also <xref linkend="persistent_state"/>.
296
<term><option>--statedir
297
<replaceable>DIRECTORY</replaceable></option></term>
299
<xi:include href="mandos-options.xml" xpointer="statedir"/>
305
<refsect1 id="overview">
306
<title>OVERVIEW</title>
307
<xi:include href="overview.xml"/>
309
This program is the server part. It is a normal server program
310
and will run in a normal system environment, not in an initial
311
<acronym>RAM</acronym> disk environment.
315
<refsect1 id="protocol">
316
<title>NETWORK PROTOCOL</title>
318
The Mandos server announces itself as a Zeroconf service of type
319
<quote><literal>_mandos._tcp</literal></quote>. The Mandos
320
client connects to the announced address and port, and sends a
321
line of text where the first whitespace-separated field is the
322
protocol version, which currently is
323
<quote><literal>1</literal></quote>. The client and server then
324
start a TLS protocol handshake with a slight quirk: the Mandos
325
server program acts as a TLS <quote>client</quote> while the
326
connecting Mandos client acts as a TLS <quote>server</quote>.
327
The Mandos client must supply an OpenPGP certificate, and the
328
fingerprint of this certificate is used by the Mandos server to
329
look up (in a list read from <filename>clients.conf</filename>
330
at start time) which binary blob to give the client. No other
331
authentication or authorization is done by the server.
334
<title>Mandos Protocol (Version 1)</title><tgroup cols="3"><thead>
336
<entry>Mandos Client</entry>
337
<entry>Direction</entry>
338
<entry>Mandos Server</entry>
342
<entry>Connect</entry>
343
<entry>-><!-- → --></entry>
346
<entry><quote><literal>1\r\n</literal></quote></entry>
347
<entry>-><!-- → --></entry>
350
<entry>TLS handshake <emphasis>as TLS <quote>server</quote>
352
<entry><-><!-- ⟷ --></entry>
353
<entry>TLS handshake <emphasis>as TLS <quote>client</quote>
357
<entry>OpenPGP public key (part of TLS handshake)</entry>
358
<entry>-><!-- → --></entry>
362
<entry><-<!-- ← --></entry>
363
<entry>Binary blob (client will assume OpenPGP data)</entry>
367
<entry><-<!-- ← --></entry>
370
</tbody></tgroup></table>
373
<refsect1 id="checking">
374
<title>CHECKING</title>
376
The server will, by default, continually check that the clients
377
are still up. If a client has not been confirmed as being up
378
for some time, the client is assumed to be compromised and is no
379
longer eligible to receive the encrypted password. (Manual
380
intervention is required to re-enable a client.) The timeout,
381
extended timeout, checker program, and interval between checks
382
can be configured both globally and per client; see
383
<citerefentry><refentrytitle>mandos-clients.conf</refentrytitle>
384
<manvolnum>5</manvolnum></citerefentry>.
388
<refsect1 id="approval">
389
<title>APPROVAL</title>
391
The server can be configured to require manual approval for a
392
client before it is sent its secret. The delay to wait for such
393
approval and the default action (approve or deny) can be
394
configured both globally and per client; see <citerefentry>
395
<refentrytitle>mandos-clients.conf</refentrytitle>
396
<manvolnum>5</manvolnum></citerefentry>. By default all clients
397
will be approved immediately without delay.
400
This can be used to deny a client its secret if not manually
401
approved within a specified time. It can also be used to make
402
the server delay before giving a client its secret, allowing
403
optional manual denying of this specific client.
408
<refsect1 id="logging">
409
<title>LOGGING</title>
411
The server will send log message with various severity levels to
412
<filename class="devicefile">/dev/log</filename>. With the
413
<option>--debug</option> option, it will log even more messages,
414
and also show them on the console.
418
<refsect1 id="persistent_state">
419
<title>PERSISTENT STATE</title>
421
Client settings, initially read from
422
<filename>clients.conf</filename>, are persistent across
423
restarts, and run-time changes will override settings in
424
<filename>clients.conf</filename>. However, if a setting is
425
<emphasis>changed</emphasis> (or a client added, or removed) in
426
<filename>clients.conf</filename>, this will take precedence.
430
<refsect1 id="dbus_interface">
431
<title>D-BUS INTERFACE</title>
433
The server will by default provide a D-Bus system bus interface.
434
This interface will only be accessible by the root user or a
435
Mandos-specific user, if such a user exists. For documentation
436
of the D-Bus API, see the file <filename>DBUS-API</filename>.
440
<refsect1 id="exit_status">
441
<title>EXIT STATUS</title>
443
The server will exit with a non-zero exit status only when a
444
critical error is encountered.
448
<refsect1 id="environment">
449
<title>ENVIRONMENT</title>
452
<term><envar>PATH</envar></term>
455
To start the configured checker (see <xref
456
linkend="checking"/>), the server uses
457
<filename>/bin/sh</filename>, which in turn uses
458
<varname>PATH</varname> to search for matching commands if
459
an absolute path is not given. See <citerefentry>
460
<refentrytitle>sh</refentrytitle><manvolnum>1</manvolnum>
468
<refsect1 id="files">
471
Use the <option>--configdir</option> option to change where
472
<command>&COMMANDNAME;</command> looks for its configurations
473
files. The default file names are listed here.
477
<term><filename>/etc/mandos/mandos.conf</filename></term>
480
Server-global settings. See
481
<citerefentry><refentrytitle>mandos.conf</refentrytitle>
482
<manvolnum>5</manvolnum></citerefentry> for details.
487
<term><filename>/etc/mandos/clients.conf</filename></term>
490
List of clients and client-specific settings. See
491
<citerefentry><refentrytitle>mandos-clients.conf</refentrytitle>
492
<manvolnum>5</manvolnum></citerefentry> for details.
497
<term><filename>/var/run/mandos.pid</filename></term>
500
The file containing the process id of the
501
<command>&COMMANDNAME;</command> process started last.
506
<term><filename class="devicefile">/dev/log</filename></term>
510
class="directory">/var/lib/mandos</filename></term>
513
Directory where persistent state will be saved. Change
514
this with the <option>--statedir</option> option. See
515
also the <option>--no-restore</option> option.
520
<term><filename>/dev/log</filename></term>
523
The Unix domain socket to where local syslog messages are
529
<term><filename>/bin/sh</filename></term>
532
This is used to start the configured checker command for
533
each client. See <citerefentry>
534
<refentrytitle>mandos-clients.conf</refentrytitle>
535
<manvolnum>5</manvolnum></citerefentry> for details.
545
This server might, on especially fatal errors, emit a Python
546
backtrace. This could be considered a feature.
549
There is no fine-grained control over logging and debug output.
552
Debug mode is conflated with running in the foreground.
555
This server does not check the expire time of clients’ OpenPGP
560
<refsect1 id="example">
561
<title>EXAMPLE</title>
564
Normal invocation needs no options:
567
<userinput>&COMMANDNAME;</userinput>
572
Run the server in debug mode, read configuration files from
573
the <filename class="directory">~/mandos</filename> directory,
574
and use the Zeroconf service name <quote>Test</quote> to not
575
collide with any other official Mandos server on this host:
579
<!-- do not wrap this line -->
580
<userinput>&COMMANDNAME; --debug --configdir ~/mandos --servicename Test</userinput>
586
Run the server normally, but only listen to one interface and
587
only on the link-local address on that interface:
591
<!-- do not wrap this line -->
592
<userinput>&COMMANDNAME; --interface eth7 --address fe80::aede:48ff:fe71:f6f2</userinput>
598
<refsect1 id="security">
599
<title>SECURITY</title>
600
<refsect2 id="server">
601
<title>SERVER</title>
603
Running this <command>&COMMANDNAME;</command> server program
604
should not in itself present any security risk to the host
605
computer running it. The program switches to a non-root user
609
<refsect2 id="clients">
610
<title>CLIENTS</title>
612
The server only gives out its stored data to clients which
613
does have the OpenPGP key of the stored fingerprint. This is
614
guaranteed by the fact that the client sends its OpenPGP
615
public key in the TLS handshake; this ensures it to be
616
genuine. The server computes the fingerprint of the key
617
itself and looks up the fingerprint in its list of
618
clients. The <filename>clients.conf</filename> file (see
619
<citerefentry><refentrytitle>mandos-clients.conf</refentrytitle>
620
<manvolnum>5</manvolnum></citerefentry>)
621
<emphasis>must</emphasis> be made non-readable by anyone
622
except the user starting the server (usually root).
625
As detailed in <xref linkend="checking"/>, the status of all
626
client computers will continually be checked and be assumed
627
compromised if they are gone for too long.
630
For more details on client-side security, see
631
<citerefentry><refentrytitle>mandos-client</refentrytitle>
632
<manvolnum>8mandos</manvolnum></citerefentry>.
637
<refsect1 id="see_also">
638
<title>SEE ALSO</title>
640
<citerefentry><refentrytitle>intro</refentrytitle>
641
<manvolnum>8mandos</manvolnum></citerefentry>,
642
<citerefentry><refentrytitle>mandos-clients.conf</refentrytitle>
643
<manvolnum>5</manvolnum></citerefentry>,
644
<citerefentry><refentrytitle>mandos.conf</refentrytitle>
645
<manvolnum>5</manvolnum></citerefentry>,
646
<citerefentry><refentrytitle>mandos-client</refentrytitle>
647
<manvolnum>8mandos</manvolnum></citerefentry>,
648
<citerefentry><refentrytitle>sh</refentrytitle>
649
<manvolnum>1</manvolnum></citerefentry>
654
<ulink url="http://www.zeroconf.org/">Zeroconf</ulink>
658
Zeroconf is the network protocol standard used by clients
659
for finding this Mandos server on the local network.
665
<ulink url="http://www.avahi.org/">Avahi</ulink>
669
Avahi is the library this server calls to implement
670
Zeroconf service announcements.
676
<ulink url="http://www.gnu.org/software/gnutls/"
681
GnuTLS is the library this server uses to implement TLS for
682
communicating securely with the client, and at the same time
683
confidently get the client’s public OpenPGP key.
689
RFC 4291: <citetitle>IP Version 6 Addressing
690
Architecture</citetitle>
695
<term>Section 2.2: <citetitle>Text Representation of
696
Addresses</citetitle></term>
697
<listitem><para/></listitem>
700
<term>Section 2.5.5.2: <citetitle>IPv4-Mapped IPv6
701
Address</citetitle></term>
702
<listitem><para/></listitem>
705
<term>Section 2.5.6, <citetitle>Link-Local IPv6 Unicast
706
Addresses</citetitle></term>
709
The clients use IPv6 link-local addresses, which are
710
immediately usable since a link-local addresses is
711
automatically assigned to a network interfaces when it
721
RFC 4346: <citetitle>The Transport Layer Security (TLS)
722
Protocol Version 1.1</citetitle>
726
TLS 1.1 is the protocol implemented by GnuTLS.
732
RFC 4880: <citetitle>OpenPGP Message Format</citetitle>
736
The data sent to clients is binary encrypted OpenPGP data.
742
RFC 5081: <citetitle>Using OpenPGP Keys for Transport Layer
747
This is implemented by GnuTLS and used by this server so
748
that OpenPGP keys can be used.
755
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756
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