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
45
<holder>Teddy Hogeborn</holder>
36
46
<holder>Björn Påhlsson</holder>
86
96
<arg><option>--debug</option></arg>
98
<arg><option>--debuglevel
99
<replaceable>LEVEL</replaceable></option></arg>
88
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>
91
118
<command>&COMMANDNAME;</command>
110
137
<command>&COMMANDNAME;</command> is a server daemon which
111
138
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
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.
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>.
194
241
<term><option>--priority <replaceable>
195
242
PRIORITY</replaceable></option></term>
237
284
<xi:include href="mandos-options.xml" xpointer="dbus"/>
239
See also <xref linkend="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"/>
264
361
start a TLS protocol handshake with a slight quirk: the Mandos
265
362
server program acts as a TLS <quote>client</quote> while the
266
363
connecting Mandos client acts as a TLS <quote>server</quote>.
267
The Mandos client must supply an OpenPGP certificate, and the
268
fingerprint of this certificate is used by the Mandos server to
269
look up (in a list read from <filename>clients.conf</filename>
270
at start time) which binary blob to give the client. No other
271
authentication or authorization is done by the server.
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.
274
371
<title>Mandos Protocol (Version 1)</title><tgroup cols="3"><thead>
316
413
The server will, by default, continually check that the clients
317
414
are still up. If a client has not been confirmed as being up
318
415
for some time, the client is assumed to be compromised and is no
319
longer eligible to receive the encrypted password. The timeout,
320
checker program, and interval between checks can be configured
321
both globally and per client; see <citerefentry>
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>
322
432
<refentrytitle>mandos-clients.conf</refentrytitle>
323
<manvolnum>5</manvolnum></citerefentry>.
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.
327
445
<refsect1 id="logging">
328
446
<title>LOGGING</title>
330
448
The server will send log message with various severity levels to
331
<filename>/dev/log</filename>. With the
449
<filename class="devicefile">/dev/log</filename>. With the
332
450
<option>--debug</option> option, it will log even more messages,
333
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">
338
468
<title>D-BUS INTERFACE</title>
340
470
The server will by default provide a D-Bus system bus interface.
341
471
This interface will only be accessible by the root user or a
342
Mandos-specific user, if such a user exists.
472
Mandos-specific user, if such a user exists. For documentation
473
of the D-Bus API, see the file <filename>DBUS-API</filename>.
347
477
<refsect1 id="exit_status">
348
478
<title>EXIT STATUS</title>
404
<term><filename>/var/run/mandos.pid</filename></term>
407
The file containing the process id of
408
<command>&COMMANDNAME;</command>.
413
<term><filename>/dev/log</filename></term>
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>
416
561
The Unix domain socket to where local syslog messages are
439
584
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
587
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 time stamp.
462
This server does not check the expire time of clients’ OpenPGP
589
<xi:include href="bugs.xml"/>
467
592
<refsect1 id="example">
477
602
<informalexample>
479
604
Run the server in debug mode, read configuration files from
480
the <filename>~/mandos</filename> directory, and use the
481
Zeroconf service name <quote>Test</quote> to not collide with
482
any other official Mandos server on this host:
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:
517
642
<title>CLIENTS</title>
519
644
The server only gives out its stored data to clients which
520
does have the OpenPGP key of the stored fingerprint. This is
521
guaranteed by the fact that the client sends its OpenPGP
522
public key in the TLS handshake; this ensures it to be
523
genuine. The server computes the fingerprint of the key
524
itself and looks up the fingerprint in its list of
525
clients. The <filename>clients.conf</filename> file (see
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>
526
651
<citerefentry><refentrytitle>mandos-clients.conf</refentrytitle>
527
652
<manvolnum>5</manvolnum></citerefentry>)
528
653
<emphasis>must</emphasis> be made non-readable by anyone
534
659
compromised if they are gone for too long.
537
If a client is compromised, its downtime should be duly noted
538
by the server which would therefore declare the client
539
invalid. But if the server was ever restarted, it would
540
re-read its client list from its configuration file and again
541
regard all clients therein as valid, and hence eligible to
542
receive their passwords. Therefore, be careful when
543
restarting servers if it is suspected that a client has, in
544
fact, been compromised by parties who may now be running a
545
fake Mandos client with the keys from the non-encrypted
546
initial <acronym>RAM</acronym> image of the client host. What
547
should be done in that case (if restarting the server program
548
really is necessary) is to stop the server program, edit the
549
configuration file to omit any suspect clients, and restart
553
662
For more details on client-side security, see
554
663
<citerefentry><refentrytitle>mandos-client</refentrytitle>
555
664
<manvolnum>8mandos</manvolnum></citerefentry>.
560
669
<refsect1 id="see_also">
561
670
<title>SEE ALSO</title>
564
<refentrytitle>mandos-clients.conf</refentrytitle>
565
<manvolnum>5</manvolnum></citerefentry>, <citerefentry>
566
<refentrytitle>mandos.conf</refentrytitle>
567
<manvolnum>5</manvolnum></citerefentry>, <citerefentry>
568
<refentrytitle>mandos-client</refentrytitle>
569
<manvolnum>8mandos</manvolnum></citerefentry>, <citerefentry>
570
<refentrytitle>sh</refentrytitle><manvolnum>1</manvolnum>
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>
664
RFC 5081: <citetitle>Using OpenPGP Keys for Transport Layer
669
This is implemented by GnuTLS and used by this server so
670
that OpenPGP keys can be used.
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