67
57
<refname><command>&COMMANDNAME;</command></refname>
69
Sends encrypted passwords to authenticated mandos clients
59
Gives encrypted passwords to authenticated Mandos clients
75
65
<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>
67
<arg choice="plain"><option>--interface
68
<replaceable>NAME</replaceable></option></arg>
69
<arg choice="plain"><option>-i
70
<replaceable>NAME</replaceable></option></arg>
74
<arg choice="plain"><option>--address
75
<replaceable>ADDRESS</replaceable></option></arg>
76
<arg choice="plain"><option>-a
77
<replaceable>ADDRESS</replaceable></option></arg>
81
<arg choice="plain"><option>--port
82
<replaceable>PORT</replaceable></option></arg>
83
<arg choice="plain"><option>-p
84
<replaceable>PORT</replaceable></option></arg>
87
<arg><option>--priority
88
<replaceable>PRIORITY</replaceable></option></arg>
90
<arg><option>--servicename
91
<replaceable>NAME</replaceable></option></arg>
93
<arg><option>--configdir
94
<replaceable>DIRECTORY</replaceable></option></arg>
96
<arg><option>--debug</option></arg>
98
<arg><option>--debuglevel
99
<replaceable>LEVEL</replaceable></option></arg>
101
<arg><option>--no-dbus</option></arg>
103
<arg><option>--no-ipv6</option></arg>
105
<arg><option>--no-restore</option></arg>
107
<arg><option>--statedir
108
<replaceable>DIRECTORY</replaceable></option></arg>
110
<arg><option>--socket
111
<replaceable>FD</replaceable></option></arg>
113
<arg><option>--foreground</option></arg>
115
<arg><option>--no-zeroconf</option></arg>
118
<command>&COMMANDNAME;</command>
120
<arg choice="plain"><option>--help</option></arg>
121
<arg choice="plain"><option>-h</option></arg>
125
<command>&COMMANDNAME;</command>
126
<arg choice="plain"><option>--version</option></arg>
129
<command>&COMMANDNAME;</command>
130
<arg choice="plain"><option>--check</option></arg>
98
134
<refsect1 id="description">
99
135
<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
137
<command>&COMMANDNAME;</command> is a server daemon which
138
handles incoming request for passwords for a pre-defined list of
139
client host computers. For an introduction, see
140
<citerefentry><refentrytitle>intro</refentrytitle>
141
<manvolnum>8mandos</manvolnum></citerefentry>. The Mandos server
142
uses Zeroconf to announce itself on the local network, and uses
143
TLS to communicate securely with and to authenticate the
144
clients. The Mandos server uses IPv6 to allow Mandos clients to
145
use IPv6 link-local addresses, since the clients will probably
146
not have any other addresses configured (see <xref
147
linkend="overview"/>). Any authenticated client is then given
148
the stored pre-encrypted password for that specific client.
152
<refsect1 id="purpose">
153
<title>PURPOSE</title>
155
The purpose of this is to enable <emphasis>remote and unattended
156
rebooting</emphasis> of client host computer with an
157
<emphasis>encrypted root file system</emphasis>. See <xref
158
linkend="overview"/> for details.
162
<refsect1 id="options">
163
<title>OPTIONS</title>
166
<term><option>--help</option></term>
167
<term><option>-h</option></term>
170
Show a help message and exit
176
<term><option>--interface</option>
177
<replaceable>NAME</replaceable></term>
178
<term><option>-i</option>
179
<replaceable>NAME</replaceable></term>
181
<xi:include href="mandos-options.xml" xpointer="interface"/>
186
<term><option>--address
187
<replaceable>ADDRESS</replaceable></option></term>
189
<replaceable>ADDRESS</replaceable></option></term>
191
<xi:include href="mandos-options.xml" xpointer="address"/>
197
<replaceable>PORT</replaceable></option></term>
199
<replaceable>PORT</replaceable></option></term>
201
<xi:include href="mandos-options.xml" xpointer="port"/>
206
<term><option>--check</option></term>
209
Run the server’s self-tests. This includes any unit
216
<term><option>--debug</option></term>
218
<xi:include href="mandos-options.xml" xpointer="debug"/>
223
<term><option>--debuglevel
224
<replaceable>LEVEL</replaceable></option></term>
227
Set the debugging log level.
228
<replaceable>LEVEL</replaceable> is a string, one of
229
<quote><literal>CRITICAL</literal></quote>,
230
<quote><literal>ERROR</literal></quote>,
231
<quote><literal>WARNING</literal></quote>,
232
<quote><literal>INFO</literal></quote>, or
233
<quote><literal>DEBUG</literal></quote>, in order of
234
increasing verbosity. The default level is
235
<quote><literal>WARNING</literal></quote>.
241
<term><option>--priority <replaceable>
242
PRIORITY</replaceable></option></term>
244
<xi:include href="mandos-options.xml" xpointer="priority"/>
249
<term><option>--servicename
250
<replaceable>NAME</replaceable></option></term>
252
<xi:include href="mandos-options.xml"
253
xpointer="servicename"/>
258
<term><option>--configdir
259
<replaceable>DIRECTORY</replaceable></option></term>
262
Directory to search for configuration files. Default is
263
<quote><literal>/etc/mandos</literal></quote>. See
264
<citerefentry><refentrytitle>mandos.conf</refentrytitle>
265
<manvolnum>5</manvolnum></citerefentry> and <citerefentry>
266
<refentrytitle>mandos-clients.conf</refentrytitle>
267
<manvolnum>5</manvolnum></citerefentry>.
273
<term><option>--version</option></term>
276
Prints the program version and exit.
282
<term><option>--no-dbus</option></term>
284
<xi:include href="mandos-options.xml" xpointer="dbus"/>
286
See also <xref linkend="dbus_interface"/>.
292
<term><option>--no-ipv6</option></term>
294
<xi:include href="mandos-options.xml" xpointer="ipv6"/>
299
<term><option>--no-restore</option></term>
301
<xi:include href="mandos-options.xml" xpointer="restore"/>
303
See also <xref linkend="persistent_state"/>.
309
<term><option>--statedir
310
<replaceable>DIRECTORY</replaceable></option></term>
312
<xi:include href="mandos-options.xml" xpointer="statedir"/>
317
<term><option>--socket
318
<replaceable>FD</replaceable></option></term>
320
<xi:include href="mandos-options.xml" xpointer="socket"/>
325
<term><option>--foreground</option></term>
327
<xi:include href="mandos-options.xml"
328
xpointer="foreground"/>
333
<term><option>--no-zeroconf</option></term>
335
<xi:include href="mandos-options.xml" xpointer="zeroconf"/>
342
<refsect1 id="overview">
343
<title>OVERVIEW</title>
344
<xi:include href="overview.xml"/>
346
This program is the server part. It is a normal server program
347
and will run in a normal system environment, not in an initial
348
<acronym>RAM</acronym> disk environment.
352
<refsect1 id="protocol">
353
<title>NETWORK PROTOCOL</title>
355
The Mandos server announces itself as a Zeroconf service of type
356
<quote><literal>_mandos._tcp</literal></quote>. The Mandos
357
client connects to the announced address and port, and sends a
358
line of text where the first whitespace-separated field is the
359
protocol version, which currently is
360
<quote><literal>1</literal></quote>. The client and server then
361
start a TLS protocol handshake with a slight quirk: the Mandos
362
server program acts as a TLS <quote>client</quote> while the
363
connecting Mandos client acts as a TLS <quote>server</quote>.
364
The Mandos client must supply a TLS public key, and the key ID
365
of this public key is used by the Mandos server to look up (in a
366
list read from <filename>clients.conf</filename> at start time)
367
which binary blob to give the client. No other authentication
368
or authorization is done by the server.
371
<title>Mandos Protocol (Version 1)</title><tgroup cols="3"><thead>
373
<entry>Mandos Client</entry>
374
<entry>Direction</entry>
375
<entry>Mandos Server</entry>
379
<entry>Connect</entry>
380
<entry>-><!-- → --></entry>
383
<entry><quote><literal>1\r\n</literal></quote></entry>
384
<entry>-><!-- → --></entry>
387
<entry>TLS handshake <emphasis>as TLS <quote>server</quote>
389
<entry><-><!-- ⟷ --></entry>
390
<entry>TLS handshake <emphasis>as TLS <quote>client</quote>
394
<entry>Public key (part of TLS handshake)</entry>
395
<entry>-><!-- → --></entry>
399
<entry><-<!-- ← --></entry>
400
<entry>Binary blob (client will assume OpenPGP data)</entry>
404
<entry><-<!-- ← --></entry>
407
</tbody></tgroup></table>
410
<refsect1 id="checking">
411
<title>CHECKING</title>
413
The server will, by default, continually check that the clients
414
are still up. If a client has not been confirmed as being up
415
for some time, the client is assumed to be compromised and is no
416
longer eligible to receive the encrypted password. (Manual
417
intervention is required to re-enable a client.) The timeout,
418
extended timeout, checker program, and interval between checks
419
can be configured both globally and per client; see
420
<citerefentry><refentrytitle>mandos-clients.conf</refentrytitle>
421
<manvolnum>5</manvolnum></citerefentry>.
425
<refsect1 id="approval">
426
<title>APPROVAL</title>
428
The server can be configured to require manual approval for a
429
client before it is sent its secret. The delay to wait for such
430
approval and the default action (approve or deny) can be
431
configured both globally and per client; see <citerefentry>
432
<refentrytitle>mandos-clients.conf</refentrytitle>
433
<manvolnum>5</manvolnum></citerefentry>. By default all clients
434
will be approved immediately without delay.
437
This can be used to deny a client its secret if not manually
438
approved within a specified time. It can also be used to make
439
the server delay before giving a client its secret, allowing
440
optional manual denying of this specific client.
445
<refsect1 id="logging">
446
<title>LOGGING</title>
448
The server will send log message with various severity levels to
449
<filename class="devicefile">/dev/log</filename>. With the
450
<option>--debug</option> option, it will log even more messages,
451
and also show them on the console.
455
<refsect1 id="persistent_state">
456
<title>PERSISTENT STATE</title>
458
Client settings, initially read from
459
<filename>clients.conf</filename>, are persistent across
460
restarts, and run-time changes will override settings in
461
<filename>clients.conf</filename>. However, if a setting is
462
<emphasis>changed</emphasis> (or a client added, or removed) in
463
<filename>clients.conf</filename>, this will take precedence.
467
<refsect1 id="dbus_interface">
468
<title>D-BUS INTERFACE</title>
470
The server will by default provide a D-Bus system bus interface.
471
This interface will only be accessible by the root user or a
472
Mandos-specific user, if such a user exists. For documentation
473
of the D-Bus API, see the file <filename>DBUS-API</filename>.
477
<refsect1 id="exit_status">
478
<title>EXIT STATUS</title>
480
The server will exit with a non-zero exit status only when a
481
critical error is encountered.
485
<refsect1 id="environment">
486
<title>ENVIRONMENT</title>
489
<term><envar>PATH</envar></term>
492
To start the configured checker (see <xref
493
linkend="checking"/>), the server uses
494
<filename>/bin/sh</filename>, which in turn uses
495
<varname>PATH</varname> to search for matching commands if
496
an absolute path is not given. See <citerefentry>
497
<refentrytitle>sh</refentrytitle><manvolnum>1</manvolnum>
505
<refsect1 id="files">
508
Use the <option>--configdir</option> option to change where
509
<command>&COMMANDNAME;</command> looks for its configurations
510
files. The default file names are listed here.
514
<term><filename>/etc/mandos/mandos.conf</filename></term>
517
Server-global settings. See
518
<citerefentry><refentrytitle>mandos.conf</refentrytitle>
519
<manvolnum>5</manvolnum></citerefentry> for details.
524
<term><filename>/etc/mandos/clients.conf</filename></term>
527
List of clients and client-specific settings. See
528
<citerefentry><refentrytitle>mandos-clients.conf</refentrytitle>
529
<manvolnum>5</manvolnum></citerefentry> for details.
534
<term><filename>/run/mandos.pid</filename></term>
537
The file containing the process id of the
538
<command>&COMMANDNAME;</command> process started last.
539
<emphasis >Note:</emphasis> If the <filename
540
class="directory">/run</filename> directory does not
541
exist, <filename>/var/run/mandos.pid</filename> will be
548
class="directory">/var/lib/mandos</filename></term>
551
Directory where persistent state will be saved. Change
552
this with the <option>--statedir</option> option. See
553
also the <option>--no-restore</option> option.
558
<term><filename class="devicefile">/dev/log</filename></term>
561
The Unix domain socket to where local syslog messages are
567
<term><filename>/bin/sh</filename></term>
570
This is used to start the configured checker command for
571
each client. See <citerefentry>
572
<refentrytitle>mandos-clients.conf</refentrytitle>
573
<manvolnum>5</manvolnum></citerefentry> for details.
583
This server might, on especially fatal errors, emit a Python
584
backtrace. This could be considered a feature.
587
There is no fine-grained control over logging and debug output.
589
<xi:include href="bugs.xml"/>
592
<refsect1 id="example">
593
<title>EXAMPLE</title>
596
Normal invocation needs no options:
599
<userinput>&COMMANDNAME;</userinput>
604
Run the server in debug mode, read configuration files from
605
the <filename class="directory">~/mandos</filename> directory,
606
and use the Zeroconf service name <quote>Test</quote> to not
607
collide with any other official Mandos server on this host:
611
<!-- do not wrap this line -->
612
<userinput>&COMMANDNAME; --debug --configdir ~/mandos --servicename Test</userinput>
618
Run the server normally, but only listen to one interface and
619
only on the link-local address on that interface:
623
<!-- do not wrap this line -->
624
<userinput>&COMMANDNAME; --interface eth7 --address fe80::aede:48ff:fe71:f6f2</userinput>
630
<refsect1 id="security">
631
<title>SECURITY</title>
632
<refsect2 id="server">
633
<title>SERVER</title>
635
Running this <command>&COMMANDNAME;</command> server program
636
should not in itself present any security risk to the host
637
computer running it. The program switches to a non-root user
641
<refsect2 id="clients">
642
<title>CLIENTS</title>
644
The server only gives out its stored data to clients which
645
does have the correct key ID of the stored key ID. This is
646
guaranteed by the fact that the client sends its public key in
647
the TLS handshake; this ensures it to be genuine. The server
648
computes the key ID of the key itself and looks up the key ID
649
in its list of clients. The <filename>clients.conf</filename>
651
<citerefentry><refentrytitle>mandos-clients.conf</refentrytitle>
652
<manvolnum>5</manvolnum></citerefentry>)
653
<emphasis>must</emphasis> be made non-readable by anyone
654
except the user starting the server (usually root).
657
As detailed in <xref linkend="checking"/>, the status of all
658
client computers will continually be checked and be assumed
659
compromised if they are gone for too long.
662
For more details on client-side security, see
663
<citerefentry><refentrytitle>mandos-client</refentrytitle>
664
<manvolnum>8mandos</manvolnum></citerefentry>.
669
<refsect1 id="see_also">
670
<title>SEE ALSO</title>
672
<citerefentry><refentrytitle>intro</refentrytitle>
673
<manvolnum>8mandos</manvolnum></citerefentry>,
674
<citerefentry><refentrytitle>mandos-clients.conf</refentrytitle>
675
<manvolnum>5</manvolnum></citerefentry>,
676
<citerefentry><refentrytitle>mandos.conf</refentrytitle>
677
<manvolnum>5</manvolnum></citerefentry>,
678
<citerefentry><refentrytitle>mandos-client</refentrytitle>
679
<manvolnum>8mandos</manvolnum></citerefentry>,
680
<citerefentry><refentrytitle>sh</refentrytitle>
681
<manvolnum>1</manvolnum></citerefentry>
686
<ulink url="http://www.zeroconf.org/">Zeroconf</ulink>
690
Zeroconf is the network protocol standard used by clients
691
for finding this Mandos server on the local network.
697
<ulink url="http://www.avahi.org/">Avahi</ulink>
701
Avahi is the library this server calls to implement
702
Zeroconf service announcements.
708
<ulink url="https://gnutls.org/">GnuTLS</ulink>
712
GnuTLS is the library this server uses to implement TLS for
713
communicating securely with the client, and at the same time
714
confidently get the client’s public key.
720
RFC 4291: <citetitle>IP Version 6 Addressing
721
Architecture</citetitle>
726
<term>Section 2.2: <citetitle>Text Representation of
727
Addresses</citetitle></term>
728
<listitem><para/></listitem>
731
<term>Section 2.5.5.2: <citetitle>IPv4-Mapped IPv6
732
Address</citetitle></term>
733
<listitem><para/></listitem>
736
<term>Section 2.5.6, <citetitle>Link-Local IPv6 Unicast
737
Addresses</citetitle></term>
740
The clients use IPv6 link-local addresses, which are
741
immediately usable since a link-local addresses is
742
automatically assigned to a network interfaces when it
752
RFC 5246: <citetitle>The Transport Layer Security (TLS)
753
Protocol Version 1.2</citetitle>
757
TLS 1.2 is the protocol implemented by GnuTLS.
763
RFC 4880: <citetitle>OpenPGP Message Format</citetitle>
767
The data sent to clients is binary encrypted OpenPGP data.
773
RFC 7250: <citetitle>Using Raw Public Keys in Transport
774
Layer Security (TLS) and Datagram Transport Layer Security
779
This is implemented by GnuTLS version 3.6.6 and is, if
780
present, used by this server so that raw public keys can be
787
RFC 6091: <citetitle>Using OpenPGP Keys for Transport Layer
788
Security (TLS) Authentication</citetitle>
792
This is implemented by GnuTLS before version 3.6.0 and is,
793
if present, used by this server so that OpenPGP keys can be
801
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