19
19
<firstname>Björn</firstname>
20
20
<surname>Påhlsson</surname>
22
<email>belorn@fukt.bsnet.se</email>
22
<email>belorn@recompile.se</email>
26
26
<firstname>Teddy</firstname>
27
27
<surname>Hogeborn</surname>
29
<email>teddy@fukt.bsnet.se</email>
29
<email>teddy@recompile.se</email>
35
46
<holder>Teddy Hogeborn</holder>
36
47
<holder>Björn Påhlsson</holder>
86
97
<arg><option>--debug</option></arg>
99
<arg><option>--debuglevel
100
<replaceable>LEVEL</replaceable></option></arg>
88
102
<arg><option>--no-dbus</option></arg>
104
<arg><option>--no-ipv6</option></arg>
106
<arg><option>--no-restore</option></arg>
108
<arg><option>--statedir
109
<replaceable>DIRECTORY</replaceable></option></arg>
111
<arg><option>--socket
112
<replaceable>FD</replaceable></option></arg>
114
<arg><option>--foreground</option></arg>
116
<arg><option>--no-zeroconf</option></arg>
91
119
<command>&COMMANDNAME;</command>
108
136
<title>DESCRIPTION</title>
110
138
<command>&COMMANDNAME;</command> is a server daemon which
111
handles incoming request for passwords for a pre-defined list of
112
client host computers. The Mandos server uses Zeroconf to
113
announce itself on the local network, and uses TLS to
114
communicate securely with and to authenticate the clients. The
115
Mandos server uses IPv6 to allow Mandos clients to use IPv6
116
link-local addresses, since the clients will probably not have
117
any other addresses configured (see <xref linkend="overview"/>).
118
Any authenticated client is then given the stored pre-encrypted
119
password for that specific client.
139
handles incoming requests for passwords for a pre-defined list
140
of client host computers. For an introduction, see
141
<citerefentry><refentrytitle>intro</refentrytitle>
142
<manvolnum>8mandos</manvolnum></citerefentry>. The Mandos server
143
uses Zeroconf to announce itself on the local network, and uses
144
TLS to communicate securely with and to authenticate the
145
clients. The Mandos server uses IPv6 to allow Mandos clients to
146
use IPv6 link-local addresses, since the clients will probably
147
not have any other addresses configured (see <xref
148
linkend="overview"/>). Any authenticated client is then given
149
the stored pre-encrypted password for that specific client.
224
<term><option>--debuglevel
225
<replaceable>LEVEL</replaceable></option></term>
228
Set the debugging log level.
229
<replaceable>LEVEL</replaceable> is a string, one of
230
<quote><literal>CRITICAL</literal></quote>,
231
<quote><literal>ERROR</literal></quote>,
232
<quote><literal>WARNING</literal></quote>,
233
<quote><literal>INFO</literal></quote>, or
234
<quote><literal>DEBUG</literal></quote>, in order of
235
increasing verbosity. The default level is
236
<quote><literal>WARNING</literal></quote>.
194
242
<term><option>--priority <replaceable>
195
243
PRIORITY</replaceable></option></term>
293
<term><option>--no-ipv6</option></term>
295
<xi:include href="mandos-options.xml" xpointer="ipv6"/>
300
<term><option>--no-restore</option></term>
302
<xi:include href="mandos-options.xml" xpointer="restore"/>
304
See also <xref linkend="persistent_state"/>.
310
<term><option>--statedir
311
<replaceable>DIRECTORY</replaceable></option></term>
313
<xi:include href="mandos-options.xml" xpointer="statedir"/>
318
<term><option>--socket
319
<replaceable>FD</replaceable></option></term>
321
<xi:include href="mandos-options.xml" xpointer="socket"/>
326
<term><option>--foreground</option></term>
328
<xi:include href="mandos-options.xml"
329
xpointer="foreground"/>
334
<term><option>--no-zeroconf</option></term>
336
<xi:include href="mandos-options.xml" xpointer="zeroconf"/>
265
362
start a TLS protocol handshake with a slight quirk: the Mandos
266
363
server program acts as a TLS <quote>client</quote> while the
267
364
connecting Mandos client acts as a TLS <quote>server</quote>.
268
The Mandos client must supply an OpenPGP certificate, and the
269
fingerprint of this certificate is used by the Mandos server to
270
look up (in a list read from <filename>clients.conf</filename>
271
at start time) which binary blob to give the client. No other
272
authentication or authorization is done by the server.
365
The Mandos client must supply a TLS public key, and the key ID
366
of this public key is used by the Mandos server to look up (in a
367
list read from <filename>clients.conf</filename> at start time)
368
which binary blob to give the client. No other authentication
369
or authorization is done by the server.
275
372
<title>Mandos Protocol (Version 1)</title><tgroup cols="3"><thead>
317
414
The server will, by default, continually check that the clients
318
415
are still up. If a client has not been confirmed as being up
319
416
for some time, the client is assumed to be compromised and is no
320
longer eligible to receive the encrypted password. The timeout,
321
checker program, and interval between checks can be configured
322
both globally and per client; see <citerefentry>
417
longer eligible to receive the encrypted password. (Manual
418
intervention is required to re-enable a client.) The timeout,
419
extended timeout, checker program, and interval between checks
420
can be configured both globally and per client; see
421
<citerefentry><refentrytitle>mandos-clients.conf</refentrytitle>
422
<manvolnum>5</manvolnum></citerefentry>.
426
<refsect1 id="approval">
427
<title>APPROVAL</title>
429
The server can be configured to require manual approval for a
430
client before it is sent its secret. The delay to wait for such
431
approval and the default action (approve or deny) can be
432
configured both globally and per client; see <citerefentry>
323
433
<refentrytitle>mandos-clients.conf</refentrytitle>
324
<manvolnum>5</manvolnum></citerefentry>.
434
<manvolnum>5</manvolnum></citerefentry>. By default all clients
435
will be approved immediately without delay.
438
This can be used to deny a client its secret if not manually
439
approved within a specified time. It can also be used to make
440
the server delay before giving a client its secret, allowing
441
optional manual denying of this specific client.
328
446
<refsect1 id="logging">
329
447
<title>LOGGING</title>
331
449
The server will send log message with various severity levels to
332
<filename>/dev/log</filename>. With the
450
<filename class="devicefile">/dev/log</filename>. With the
333
451
<option>--debug</option> option, it will log even more messages,
334
452
and also show them on the console.
456
<refsect1 id="persistent_state">
457
<title>PERSISTENT STATE</title>
459
Client settings, initially read from
460
<filename>clients.conf</filename>, are persistent across
461
restarts, and run-time changes will override settings in
462
<filename>clients.conf</filename>. However, if a setting is
463
<emphasis>changed</emphasis> (or a client added, or removed) in
464
<filename>clients.conf</filename>, this will take precedence.
338
468
<refsect1 id="dbus_interface">
339
469
<title>D-BUS INTERFACE</title>
341
471
The server will by default provide a D-Bus system bus interface.
342
472
This interface will only be accessible by the root user or a
343
Mandos-specific user, if such a user exists.
473
Mandos-specific user, if such a user exists. For documentation
474
of the D-Bus API, see the file <filename>DBUS-API</filename>.
348
478
<refsect1 id="exit_status">
349
479
<title>EXIT STATUS</title>
405
<term><filename>/var/run/mandos.pid</filename></term>
408
The file containing the process id of
409
<command>&COMMANDNAME;</command>.
414
<term><filename>/dev/log</filename></term>
535
<term><filename>/run/mandos.pid</filename></term>
538
The file containing the process id of the
539
<command>&COMMANDNAME;</command> process started last.
540
<emphasis >Note:</emphasis> If the <filename
541
class="directory">/run</filename> directory does not
542
exist, <filename>/var/run/mandos.pid</filename> will be
549
class="directory">/var/lib/mandos</filename></term>
552
Directory where persistent state will be saved. Change
553
this with the <option>--statedir</option> option. See
554
also the <option>--no-restore</option> option.
559
<term><filename class="devicefile">/dev/log</filename></term>
417
562
The Unix domain socket to where local syslog messages are
440
585
backtrace. This could be considered a feature.
443
Currently, if a client is declared <quote>invalid</quote> due to
444
having timed out, the server does not record this fact onto
445
permanent storage. This has some security implications, see
446
<xref linkend="clients"/>.
449
There is currently no way of querying the server of the current
450
status of clients, other than analyzing its <systemitem
451
class="service">syslog</systemitem> output.
454
588
There is no fine-grained control over logging and debug output.
457
Debug mode is conflated with running in the foreground.
460
The console log messages does not show a time stamp.
463
This server does not check the expire time of clients’ OpenPGP
590
<xi:include href="bugs.xml"/>
468
593
<refsect1 id="example">
478
603
<informalexample>
480
605
Run the server in debug mode, read configuration files from
481
the <filename>~/mandos</filename> directory, and use the
482
Zeroconf service name <quote>Test</quote> to not collide with
483
any other official Mandos server on this host:
606
the <filename class="directory">~/mandos</filename> directory,
607
and use the Zeroconf service name <quote>Test</quote> to not
608
collide with any other official Mandos server on this host:
518
643
<title>CLIENTS</title>
520
645
The server only gives out its stored data to clients which
521
does have the OpenPGP key of the stored fingerprint. This is
522
guaranteed by the fact that the client sends its OpenPGP
523
public key in the TLS handshake; this ensures it to be
524
genuine. The server computes the fingerprint of the key
525
itself and looks up the fingerprint in its list of
526
clients. The <filename>clients.conf</filename> file (see
646
does have the correct key ID of the stored key ID. This is
647
guaranteed by the fact that the client sends its public key in
648
the TLS handshake; this ensures it to be genuine. The server
649
computes the key ID of the key itself and looks up the key ID
650
in its list of clients. The <filename>clients.conf</filename>
527
652
<citerefentry><refentrytitle>mandos-clients.conf</refentrytitle>
528
653
<manvolnum>5</manvolnum></citerefentry>)
529
654
<emphasis>must</emphasis> be made non-readable by anyone
535
660
compromised if they are gone for too long.
538
If a client is compromised, its downtime should be duly noted
539
by the server which would therefore declare the client
540
invalid. But if the server was ever restarted, it would
541
re-read its client list from its configuration file and again
542
regard all clients therein as valid, and hence eligible to
543
receive their passwords. Therefore, be careful when
544
restarting servers if it is suspected that a client has, in
545
fact, been compromised by parties who may now be running a
546
fake Mandos client with the keys from the non-encrypted
547
initial <acronym>RAM</acronym> image of the client host. What
548
should be done in that case (if restarting the server program
549
really is necessary) is to stop the server program, edit the
550
configuration file to omit any suspect clients, and restart
554
663
For more details on client-side security, see
555
664
<citerefentry><refentrytitle>mandos-client</refentrytitle>
556
665
<manvolnum>8mandos</manvolnum></citerefentry>.
561
670
<refsect1 id="see_also">
562
671
<title>SEE ALSO</title>
565
<refentrytitle>mandos-clients.conf</refentrytitle>
566
<manvolnum>5</manvolnum></citerefentry>, <citerefentry>
567
<refentrytitle>mandos.conf</refentrytitle>
568
<manvolnum>5</manvolnum></citerefentry>, <citerefentry>
569
<refentrytitle>mandos-client</refentrytitle>
570
<manvolnum>8mandos</manvolnum></citerefentry>, <citerefentry>
571
<refentrytitle>sh</refentrytitle><manvolnum>1</manvolnum>
673
<citerefentry><refentrytitle>intro</refentrytitle>
674
<manvolnum>8mandos</manvolnum></citerefentry>,
675
<citerefentry><refentrytitle>mandos-clients.conf</refentrytitle>
676
<manvolnum>5</manvolnum></citerefentry>,
677
<citerefentry><refentrytitle>mandos.conf</refentrytitle>
678
<manvolnum>5</manvolnum></citerefentry>,
679
<citerefentry><refentrytitle>mandos-client</refentrytitle>
680
<manvolnum>8mandos</manvolnum></citerefentry>,
681
<citerefentry><refentrytitle>sh</refentrytitle>
682
<manvolnum>1</manvolnum></citerefentry>
665
RFC 5081: <citetitle>Using OpenPGP Keys for Transport Layer
670
This is implemented by GnuTLS and used by this server so
671
that OpenPGP keys can be used.
774
RFC 7250: <citetitle>Using Raw Public Keys in Transport
775
Layer Security (TLS) and Datagram Transport Layer Security
780
This is implemented by GnuTLS version 3.6.6 and is, if
781
present, used by this server so that raw public keys can be
788
RFC 6091: <citetitle>Using OpenPGP Keys for Transport Layer
789
Security (TLS) Authentication</citetitle>
793
This is implemented by GnuTLS before version 3.6.0 and is,
794
if present, used by this server so that OpenPGP keys can be