67
52
<refname><command>&COMMANDNAME;</command></refname>
69
Sends encrypted passwords to authenticated mandos clients
54
Gives encrypted passwords to authenticated Mandos clients
75
60
<command>&COMMANDNAME;</command>
76
<arg choice='opt'>--interface<arg choice='plain'>IF</arg></arg>
77
<arg choice='opt'>--address<arg choice='plain'>ADDRESS</arg></arg>
78
<arg choice='opt'>--port<arg choice='plain'>PORT</arg></arg>
79
<arg choice='opt'>--priority<arg choice='plain'>PRIORITY</arg></arg>
80
<arg choice='opt'>--servicename<arg choice='plain'>NAME</arg></arg>
81
<arg choice='opt'>--configdir<arg choice='plain'>DIRECTORY</arg></arg>
82
<arg choice='opt'>--debug</arg>
85
<command>&COMMANDNAME;</command>
86
<arg choice='plain'>--help</arg>
89
<command>&COMMANDNAME;</command>
90
<arg choice='plain'>--version</arg>
93
<command>&COMMANDNAME;</command>
94
<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>
98
127
<refsect1 id="description">
99
128
<title>DESCRIPTION</title>
101
<command>&COMMANDNAME;</command> is a server daemon that handels
102
incomming passwords request for passwords. Mandos use avahi to
103
announce the service, and through gnutls authenticates
104
clients. Any authenticated client is then given its encrypted
110
<term><literal>-h</literal>, <literal>--help</literal></term>
113
show a help message and exit
119
<term><literal>-i</literal>, <literal>--interface <replaceable>
120
IF</replaceable></literal></term>
129
<term><literal>-a</literal>, <literal>--address <replaceable>
130
ADDRESS</replaceable></literal></term>
133
Address to listen for requests on
139
<term><literal>-p</literal>, <literal>--port <replaceable>
140
PORT</replaceable></literal></term>
143
Port number to receive requests on
149
<term><literal>--check</literal></term>
152
Run self-test on the server
158
<term><literal>--debug</literal></term>
167
<term><literal>--priority <replaceable>
168
PRIORITY</replaceable></literal></term>
171
GnuTLS priority string. See <citerefentry>
172
<refentrytitle>gnutls_priority_init</refentrytitle>
173
<manvolnum>3</manvolnum></citerefentry>
179
<term><literal>--servicename <replaceable>NAME</replaceable>
183
Zeroconf service name
189
<term><literal>--configdir <replaceable>DIR</replaceable>
193
Directory to search for configuration files
199
<term><literal>--version</literal></term>
202
Prints the program version
130
<command>&COMMANDNAME;</command> is a server daemon which
131
handles incoming request for passwords for a pre-defined list of
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.
145
<refsect1 id="purpose">
146
<title>PURPOSE</title>
148
The purpose of this is to enable <emphasis>remote and unattended
149
rebooting</emphasis> of client host computer with an
150
<emphasis>encrypted root file system</emphasis>. See <xref
151
linkend="overview"/> for details.
155
<refsect1 id="options">
156
<title>OPTIONS</title>
159
<term><option>--help</option></term>
160
<term><option>-h</option></term>
163
Show a help message and exit
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
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" xpointer="priority"/>
242
<term><option>--servicename
243
<replaceable>NAME</replaceable></option></term>
245
<xi:include href="mandos-options.xml"
246
xpointer="servicename"/>
251
<term><option>--configdir
252
<replaceable>DIRECTORY</replaceable></option></term>
255
Directory to search for configuration files. Default is
256
<quote><literal>/etc/mandos</literal></quote>. See
257
<citerefentry><refentrytitle>mandos.conf</refentrytitle>
258
<manvolnum>5</manvolnum></citerefentry> and <citerefentry>
259
<refentrytitle>mandos-clients.conf</refentrytitle>
260
<manvolnum>5</manvolnum></citerefentry>.
266
<term><option>--version</option></term>
269
Prints the program version and exit.
275
<term><option>--no-dbus</option></term>
277
<xi:include href="mandos-options.xml" xpointer="dbus"/>
279
See also <xref linkend="dbus_interface"/>.
285
<term><option>--no-ipv6</option></term>
287
<xi:include href="mandos-options.xml" xpointer="ipv6"/>
292
<term><option>--no-restore</option></term>
294
<xi:include href="mandos-options.xml" xpointer="restore"/>
296
See also <xref linkend="persistent_state"/>.
302
<term><option>--statedir
303
<replaceable>DIRECTORY</replaceable></option></term>
305
<xi:include href="mandos-options.xml" xpointer="statedir"/>
310
<term><option>--socket
311
<replaceable>FD</replaceable></option></term>
313
<xi:include href="mandos-options.xml" xpointer="socket"/>
318
<term><option>--foreground</option></term>
320
<xi:include href="mandos-options.xml"
321
xpointer="foreground"/>
328
<refsect1 id="overview">
329
<title>OVERVIEW</title>
330
<xi:include href="overview.xml"/>
332
This program is the server part. It is a normal server program
333
and will run in a normal system environment, not in an initial
334
<acronym>RAM</acronym> disk environment.
338
<refsect1 id="protocol">
339
<title>NETWORK PROTOCOL</title>
341
The Mandos server announces itself as a Zeroconf service of type
342
<quote><literal>_mandos._tcp</literal></quote>. The Mandos
343
client connects to the announced address and port, and sends a
344
line of text where the first whitespace-separated field is the
345
protocol version, which currently is
346
<quote><literal>1</literal></quote>. The client and server then
347
start a TLS protocol handshake with a slight quirk: the Mandos
348
server program acts as a TLS <quote>client</quote> while the
349
connecting Mandos client acts as a TLS <quote>server</quote>.
350
The Mandos client must supply an OpenPGP certificate, and the
351
fingerprint of this certificate is used by the Mandos server to
352
look up (in a list read from <filename>clients.conf</filename>
353
at start time) which binary blob to give the client. No other
354
authentication or authorization is done by the server.
357
<title>Mandos Protocol (Version 1)</title><tgroup cols="3"><thead>
359
<entry>Mandos Client</entry>
360
<entry>Direction</entry>
361
<entry>Mandos Server</entry>
365
<entry>Connect</entry>
366
<entry>-><!-- → --></entry>
369
<entry><quote><literal>1\r\n</literal></quote></entry>
370
<entry>-><!-- → --></entry>
373
<entry>TLS handshake <emphasis>as TLS <quote>server</quote>
375
<entry><-><!-- ⟷ --></entry>
376
<entry>TLS handshake <emphasis>as TLS <quote>client</quote>
380
<entry>OpenPGP public key (part of TLS handshake)</entry>
381
<entry>-><!-- → --></entry>
385
<entry><-<!-- ← --></entry>
386
<entry>Binary blob (client will assume OpenPGP data)</entry>
390
<entry><-<!-- ← --></entry>
393
</tbody></tgroup></table>
396
<refsect1 id="checking">
397
<title>CHECKING</title>
399
The server will, by default, continually check that the clients
400
are still up. If a client has not been confirmed as being up
401
for some time, the client is assumed to be compromised and is no
402
longer eligible to receive the encrypted password. (Manual
403
intervention is required to re-enable a client.) The timeout,
404
extended timeout, checker program, and interval between checks
405
can be configured both globally and per client; see
406
<citerefentry><refentrytitle>mandos-clients.conf</refentrytitle>
407
<manvolnum>5</manvolnum></citerefentry>.
411
<refsect1 id="approval">
412
<title>APPROVAL</title>
414
The server can be configured to require manual approval for a
415
client before it is sent its secret. The delay to wait for such
416
approval and the default action (approve or deny) can be
417
configured both globally and per client; see <citerefentry>
418
<refentrytitle>mandos-clients.conf</refentrytitle>
419
<manvolnum>5</manvolnum></citerefentry>. By default all clients
420
will be approved immediately without delay.
423
This can be used to deny a client its secret if not manually
424
approved within a specified time. It can also be used to make
425
the server delay before giving a client its secret, allowing
426
optional manual denying of this specific client.
431
<refsect1 id="logging">
432
<title>LOGGING</title>
434
The server will send log message with various severity levels to
435
<filename class="devicefile">/dev/log</filename>. With the
436
<option>--debug</option> option, it will log even more messages,
437
and also show them on the console.
441
<refsect1 id="persistent_state">
442
<title>PERSISTENT STATE</title>
444
Client settings, initially read from
445
<filename>clients.conf</filename>, are persistent across
446
restarts, and run-time changes will override settings in
447
<filename>clients.conf</filename>. However, if a setting is
448
<emphasis>changed</emphasis> (or a client added, or removed) in
449
<filename>clients.conf</filename>, this will take precedence.
453
<refsect1 id="dbus_interface">
454
<title>D-BUS INTERFACE</title>
456
The server will by default provide a D-Bus system bus interface.
457
This interface will only be accessible by the root user or a
458
Mandos-specific user, if such a user exists. For documentation
459
of the D-Bus API, see the file <filename>DBUS-API</filename>.
463
<refsect1 id="exit_status">
464
<title>EXIT STATUS</title>
466
The server will exit with a non-zero exit status only when a
467
critical error is encountered.
471
<refsect1 id="environment">
472
<title>ENVIRONMENT</title>
475
<term><envar>PATH</envar></term>
478
To start the configured checker (see <xref
479
linkend="checking"/>), the server uses
480
<filename>/bin/sh</filename>, which in turn uses
481
<varname>PATH</varname> to search for matching commands if
482
an absolute path is not given. See <citerefentry>
483
<refentrytitle>sh</refentrytitle><manvolnum>1</manvolnum>
491
<refsect1 id="files">
494
Use the <option>--configdir</option> option to change where
495
<command>&COMMANDNAME;</command> looks for its configurations
496
files. The default file names are listed here.
500
<term><filename>/etc/mandos/mandos.conf</filename></term>
503
Server-global settings. See
504
<citerefentry><refentrytitle>mandos.conf</refentrytitle>
505
<manvolnum>5</manvolnum></citerefentry> for details.
510
<term><filename>/etc/mandos/clients.conf</filename></term>
513
List of clients and client-specific settings. See
514
<citerefentry><refentrytitle>mandos-clients.conf</refentrytitle>
515
<manvolnum>5</manvolnum></citerefentry> for details.
520
<term><filename>/run/mandos.pid</filename></term>
523
The file containing the process id of the
524
<command>&COMMANDNAME;</command> process started last.
529
<term><filename class="devicefile">/dev/log</filename></term>
533
class="directory">/var/lib/mandos</filename></term>
536
Directory where persistent state will be saved. Change
537
this with the <option>--statedir</option> option. See
538
also the <option>--no-restore</option> option.
543
<term><filename>/dev/log</filename></term>
546
The Unix domain socket to where local syslog messages are
552
<term><filename>/bin/sh</filename></term>
555
This is used to start the configured checker command for
556
each client. See <citerefentry>
557
<refentrytitle>mandos-clients.conf</refentrytitle>
558
<manvolnum>5</manvolnum></citerefentry> for details.
568
This server might, on especially fatal errors, emit a Python
569
backtrace. This could be considered a feature.
572
There is no fine-grained control over logging and debug output.
575
This server does not check the expire time of clients’ OpenPGP
580
<refsect1 id="example">
581
<title>EXAMPLE</title>
584
Normal invocation needs no options:
587
<userinput>&COMMANDNAME;</userinput>
592
Run the server in debug mode, read configuration files from
593
the <filename class="directory">~/mandos</filename> directory,
594
and use the Zeroconf service name <quote>Test</quote> to not
595
collide with any other official Mandos server on this host:
599
<!-- do not wrap this line -->
600
<userinput>&COMMANDNAME; --debug --configdir ~/mandos --servicename Test</userinput>
606
Run the server normally, but only listen to one interface and
607
only on the link-local address on that interface:
611
<!-- do not wrap this line -->
612
<userinput>&COMMANDNAME; --interface eth7 --address fe80::aede:48ff:fe71:f6f2</userinput>
618
<refsect1 id="security">
619
<title>SECURITY</title>
620
<refsect2 id="server">
621
<title>SERVER</title>
623
Running this <command>&COMMANDNAME;</command> server program
624
should not in itself present any security risk to the host
625
computer running it. The program switches to a non-root user
629
<refsect2 id="clients">
630
<title>CLIENTS</title>
632
The server only gives out its stored data to clients which
633
does have the OpenPGP key of the stored fingerprint. This is
634
guaranteed by the fact that the client sends its OpenPGP
635
public key in the TLS handshake; this ensures it to be
636
genuine. The server computes the fingerprint of the key
637
itself and looks up the fingerprint in its list of
638
clients. The <filename>clients.conf</filename> file (see
639
<citerefentry><refentrytitle>mandos-clients.conf</refentrytitle>
640
<manvolnum>5</manvolnum></citerefentry>)
641
<emphasis>must</emphasis> be made non-readable by anyone
642
except the user starting the server (usually root).
645
As detailed in <xref linkend="checking"/>, the status of all
646
client computers will continually be checked and be assumed
647
compromised if they are gone for too long.
650
For more details on client-side security, see
651
<citerefentry><refentrytitle>mandos-client</refentrytitle>
652
<manvolnum>8mandos</manvolnum></citerefentry>.
657
<refsect1 id="see_also">
658
<title>SEE ALSO</title>
660
<citerefentry><refentrytitle>intro</refentrytitle>
661
<manvolnum>8mandos</manvolnum></citerefentry>,
662
<citerefentry><refentrytitle>mandos-clients.conf</refentrytitle>
663
<manvolnum>5</manvolnum></citerefentry>,
664
<citerefentry><refentrytitle>mandos.conf</refentrytitle>
665
<manvolnum>5</manvolnum></citerefentry>,
666
<citerefentry><refentrytitle>mandos-client</refentrytitle>
667
<manvolnum>8mandos</manvolnum></citerefentry>,
668
<citerefentry><refentrytitle>sh</refentrytitle>
669
<manvolnum>1</manvolnum></citerefentry>
674
<ulink url="http://www.zeroconf.org/">Zeroconf</ulink>
678
Zeroconf is the network protocol standard used by clients
679
for finding this Mandos server on the local network.
685
<ulink url="http://www.avahi.org/">Avahi</ulink>
689
Avahi is the library this server calls to implement
690
Zeroconf service announcements.
696
<ulink url="http://www.gnu.org/software/gnutls/"
701
GnuTLS is the library this server uses to implement TLS for
702
communicating securely with the client, and at the same time
703
confidently get the client’s public OpenPGP key.
709
RFC 4291: <citetitle>IP Version 6 Addressing
710
Architecture</citetitle>
715
<term>Section 2.2: <citetitle>Text Representation of
716
Addresses</citetitle></term>
717
<listitem><para/></listitem>
720
<term>Section 2.5.5.2: <citetitle>IPv4-Mapped IPv6
721
Address</citetitle></term>
722
<listitem><para/></listitem>
725
<term>Section 2.5.6, <citetitle>Link-Local IPv6 Unicast
726
Addresses</citetitle></term>
729
The clients use IPv6 link-local addresses, which are
730
immediately usable since a link-local addresses is
731
automatically assigned to a network interfaces when it
741
RFC 4346: <citetitle>The Transport Layer Security (TLS)
742
Protocol Version 1.1</citetitle>
746
TLS 1.1 is the protocol implemented by GnuTLS.
752
RFC 4880: <citetitle>OpenPGP Message Format</citetitle>
756
The data sent to clients is binary encrypted OpenPGP data.
762
RFC 5081: <citetitle>Using OpenPGP Keys for Transport Layer
767
This is implemented by GnuTLS and used by this server so
768
that OpenPGP keys can be used.
775
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