68
68
<refname><command>&COMMANDNAME;</command></refname>
70
Gives encrypted passwords to authenticated Mandos clients
70
Sends encrypted passwords to authenticated Mandos clients
76
76
<command>&COMMANDNAME;</command>
78
<arg choice="plain"><option>--interface
79
<replaceable>NAME</replaceable></option></arg>
80
<arg choice="plain"><option>-i
81
<replaceable>NAME</replaceable></option></arg>
85
<arg choice="plain"><option>--address
86
<replaceable>ADDRESS</replaceable></option></arg>
87
<arg choice="plain"><option>-a
88
<replaceable>ADDRESS</replaceable></option></arg>
92
<arg choice="plain"><option>--port
93
<replaceable>PORT</replaceable></option></arg>
94
<arg choice="plain"><option>-p
95
<replaceable>PORT</replaceable></option></arg>
98
<arg><option>--priority
99
<replaceable>PRIORITY</replaceable></option></arg>
101
<arg><option>--servicename
102
<replaceable>NAME</replaceable></option></arg>
104
<arg><option>--configdir
105
<replaceable>DIRECTORY</replaceable></option></arg>
107
<arg><option>--debug</option></arg>
110
<command>&COMMANDNAME;</command>
112
<arg choice="plain"><option>--help</option></arg>
113
<arg choice="plain"><option>-h</option></arg>
117
<command>&COMMANDNAME;</command>
118
<arg choice="plain"><option>--version</option></arg>
121
<command>&COMMANDNAME;</command>
122
<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>
124
107
</refsynopsisdiv>
126
109
<refsect1 id="description">
129
112
<command>&COMMANDNAME;</command> is a server daemon which
130
113
handles incoming request for passwords for a pre-defined list of
131
114
client host computers. The Mandos server uses Zeroconf to
132
announce itself on the local network, and uses TLS to
133
communicate securely with and to authenticate the clients. The
134
Mandos server uses IPv6 to allow Mandos clients to use IPv6
135
link-local addresses, since the clients will probably not have
136
any other addresses configured (see <xref linkend="overview"/>).
137
Any authenticated client is then given the stored pre-encrypted
138
password for that specific client.
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.
143
125
<refsect1 id="purpose">
144
126
<title>PURPOSE</title>
147
129
The purpose of this is to enable <emphasis>remote and unattended
148
rebooting</emphasis> of client host computer with an
149
<emphasis>encrypted root file system</emphasis>. See <xref
150
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
155
142
<refsect1 id="options">
156
143
<title>OPTIONS</title>
160
<term><option>-h</option></term>
161
<term><option>--help</option></term>
147
<term><literal>-h</literal>, <literal>--help</literal></term>
164
150
Show a help message and exit
170
<term><option>-i</option>
171
<replaceable>NAME</replaceable></term>
172
<term><option>--interface</option>
173
<replaceable>NAME</replaceable></term>
156
<term><literal>-i</literal>, <literal>--interface <replaceable>
157
IF</replaceable></literal></term>
175
<xi:include href="mandos-options.xml" xpointer="interface"/>
160
Only announce the server and listen to requests on network
161
interface <replaceable>IF</replaceable>. Default is to
162
use all available interfaces.
180
168
<term><literal>-a</literal>, <literal>--address <replaceable>
181
169
ADDRESS</replaceable></literal></term>
183
<xi:include href="mandos-options.xml" xpointer="address"/>
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
188
185
<term><literal>-p</literal>, <literal>--port <replaceable>
189
186
PORT</replaceable></literal></term>
191
<xi:include href="mandos-options.xml" xpointer="port"/>
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.
196
197
<term><literal>--check</literal></term>
199
Run the server’s self-tests. This includes any unit
200
Run the server's self-tests. This includes any unit
206
207
<term><literal>--debug</literal></term>
208
<xi:include href="mandos-options.xml" xpointer="debug"/>
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.
248
270
Prints the program version and exit.
255
<refsect1 id="overview">
256
<title>OVERVIEW</title>
257
<xi:include href="overview.xml"/>
259
This program is the server part. It is a normal server program
260
and will run in a normal system environment, not in an initial
261
RAM disk environment.
265
277
<refsect1 id="protocol">
266
278
<title>NETWORK PROTOCOL</title>
268
280
The Mandos server announces itself as a Zeroconf service of type
269
<quote><literal>_mandos._tcp</literal></quote>. The Mandos
270
client connects to the announced address and port, and sends a
271
line of text where the first whitespace-separated field is the
272
protocol version, which currently is
273
<quote><literal>1</literal></quote>. The client and server then
274
start a TLS protocol handshake with a slight quirk: the Mandos
275
server program acts as a TLS <quote>client</quote> while the
276
connecting Mandos client acts as a TLS <quote>server</quote>.
277
The Mandos client must supply an OpenPGP certificate, and the
278
fingerprint of this certificate is used by the Mandos server to
279
look up (in a list read from <filename>clients.conf</filename>
280
at start time) which binary blob to give the client. No other
281
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
284
<title>Mandos Protocol (Version 1)</title><tgroup cols="3"><thead>
294
<informaltable><tgroup cols="3"><thead>
286
296
<entry>Mandos Client</entry>
287
297
<entry>Direction</entry>
355
<refsect1 id="environment">
356
<title>ENVIRONMENT</title>
359
<term><envar>PATH</envar></term>
362
To start the configured checker (see <xref
363
linkend="checking"/>), the server uses
364
<filename>/bin/sh</filename>, which in turn uses
365
<varname>PATH</varname> to search for matching commands if
366
an absolute path is not given. See <citerefentry>
367
<refentrytitle>sh</refentrytitle><manvolnum>1</manvolnum>
375
351
<refsect1 id="file">
376
352
<title>FILES</title>
378
Use the <option>--configdir</option> option to change where
379
<command>&COMMANDNAME;</command> looks for its configurations
380
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>
384
<term><filename>/etc/mandos/mandos.conf</filename></term>
387
Server-global settings. See
388
<citerefentry><refentrytitle>mandos.conf</refentrytitle>
389
<manvolnum>5</manvolnum></citerefentry> for details.
394
<term><filename>/etc/mandos/clients.conf</filename></term>
397
List of clients and client-specific settings. See
398
<citerefentry><refentrytitle>mandos-clients.conf</refentrytitle>
399
<manvolnum>5</manvolnum></citerefentry> for details.
404
<term><filename>/var/run/mandos/mandos.pid</filename></term>
407
The file containing the process id of
408
<command>&COMMANDNAME;</command>.
413
<term><filename>/dev/log</filename></term>
416
The Unix domain socket to where local syslog messages are
422
<term><filename>/bin/sh</filename></term>
425
This is used to start the configured checker command for
426
each client. See <citerefentry>
427
<refentrytitle>mandos-clients.conf</refentrytitle>
428
<manvolnum>5</manvolnum></citerefentry> for details.
435
372
<refsect1 id="bugs">
436
373
<title>BUGS</title>
438
This server might, on especially fatal errors, emit a Python
439
backtrace. This could be considered a feature.
442
Currently, if a client is declared <quote>invalid</quote> due to
443
having timed out, the server does not record this fact onto
444
permanent storage. This has some security implications, see
445
<xref linkend="CLIENTS"/>.
448
There is currently no way of querying the server of the current
449
status of clients, other than analyzing its <systemitem
450
class="service">syslog</systemitem> output.
453
There is no fine-grained control over logging and debug output.
456
Debug mode is conflated with running in the foreground.
459
The console log messages does not show a timestamp.
463
<refsect1 id="example">
464
<title>EXAMPLE</title>
467
Normal invocation needs no options:
470
<userinput>&COMMANDNAME;</userinput>
475
Run the server in debug mode, read configuration files from
476
the <filename>~/mandos</filename> directory, and use the
477
Zeroconf service name <quote>Test</quote> to not collide with
478
any other official Mandos server on this host:
482
<!-- do not wrap this line -->
483
<userinput>&COMMANDNAME; --debug --configdir ~/mandos --servicename Test</userinput>
489
Run the server normally, but only listen to one interface and
490
only on the link-local address on that interface:
494
<!-- do not wrap this line -->
495
<userinput>&COMMANDNAME; --interface eth7 --address fe80::aede:48ff:fe71:f6f2</userinput>
378
<refsect1 id="examples">
379
<title>EXAMPLES</title>
501
384
<refsect1 id="security">
502
385
<title>SECURITY</title>
503
<refsect2 id="SERVER">
504
<title>SERVER</title>
506
Running this <command>&COMMANDNAME;</command> server program
507
should not in itself present any security risk to the host
508
computer running it. The program does not need any special
509
privileges to run, and is designed to run as a non-root user.
512
<refsect2 id="CLIENTS">
513
<title>CLIENTS</title>
515
The server only gives out its stored data to clients which
516
does have the OpenPGP key of the stored fingerprint. This is
517
guaranteed by the fact that the client sends its OpenPGP
518
public key in the TLS handshake; this ensures it to be
519
genuine. The server computes the fingerprint of the key
520
itself and looks up the fingerprint in its list of
521
clients. The <filename>clients.conf</filename> file (see
522
<citerefentry><refentrytitle>mandos-clients.conf</refentrytitle>
523
<manvolnum>5</manvolnum></citerefentry>)
524
<emphasis>must</emphasis> be made non-readable by anyone
525
except the user running the server.
528
As detailed in <xref linkend="checking"/>, the status of all
529
client computers will continually be checked and be assumed
530
compromised if they are gone for too long.
533
If a client is compromised, its downtime should be duly noted
534
by the server which would therefore declare the client
535
invalid. But if the server was ever restarted, it would
536
re-read its client list from its configuration file and again
537
regard all clients therein as valid, and hence eligible to
538
receive their passwords. Therefore, be careful when
539
restarting servers if it is suspected that a client has, in
540
fact, been compromised by parties who may now be running a
541
fake Mandos client with the keys from the non-encrypted
542
initial RAM image of the client host. What should be done in
543
that case (if restarting the server program really is
544
necessary) is to stop the server program, edit the
545
configuration file to omit any suspect clients, and restart
549
For more details on client-side security, see
550
<citerefentry><refentrytitle>password-request</refentrytitle>
551
<manvolnum>8mandos</manvolnum></citerefentry>.
556
390
<refsect1 id="see_also">
557
391
<title>SEE ALSO</title>
560
<refentrytitle>mandos-clients.conf</refentrytitle>
561
<manvolnum>5</manvolnum></citerefentry>, <citerefentry>
562
<refentrytitle>mandos.conf</refentrytitle>
563
<manvolnum>5</manvolnum></citerefentry>, <citerefentry>
564
<refentrytitle>password-request</refentrytitle>
565
<manvolnum>8mandos</manvolnum></citerefentry>, <citerefentry>
566
<refentrytitle>sh</refentrytitle><manvolnum>1</manvolnum>
572
<ulink url="http://www.zeroconf.org/">Zeroconf</ulink>
576
Zeroconf is the network protocol standard used by clients
577
for finding this Mandos server on the local network.
583
<ulink url="http://www.avahi.org/">Avahi</ulink>
587
Avahi is the library this server calls to implement
588
Zeroconf service announcements.
594
<ulink url="http://www.gnu.org/software/gnutls/"
599
GnuTLS is the library this server uses to implement TLS for
600
communicating securely with the client, and at the same time
601
confidently get the client’s public OpenPGP key.
607
RFC 4291: <citetitle>IP Version 6 Addressing
608
Architecture</citetitle>
613
<term>Section 2.2: <citetitle>Text Representation of
614
Addresses</citetitle></term>
615
<listitem><para/></listitem>
618
<term>Section 2.5.5.2: <citetitle>IPv4-Mapped IPv6
619
Address</citetitle></term>
620
<listitem><para/></listitem>
623
<term>Section 2.5.6, <citetitle>Link-Local IPv6 Unicast
624
Addresses</citetitle></term>
627
The clients use IPv6 link-local addresses, which are
628
immediately usable since a link-local addresses is
629
automatically assigned to a network interfaces when it
639
RFC 4346: <citetitle>The Transport Layer Security (TLS)
640
Protocol Version 1.1</citetitle>
644
TLS 1.1 is the protocol implemented by GnuTLS.
650
RFC 4880: <citetitle>OpenPGP Message Format</citetitle>
654
The data sent to clients is binary encrypted OpenPGP data.
660
RFC 5081: <citetitle>Using OpenPGP Keys for Transport Layer
665
This is implemented by GnuTLS and used by this server so
666
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
428
Architecture</citetitle>, section 2.5.6, Link-Local IPv6
429
Unicast Addresses</citation>
673
<!-- Local Variables: -->
674
<!-- time-stamp-start: "<!ENTITY TIMESTAMP [\"']" -->
675
<!-- time-stamp-end: "[\"']>" -->
676
<!-- time-stamp-format: "%:y-%02m-%02d" -->