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<firstname>Björn</firstname>
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<surname>Påhlsson</surname>
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<email>belorn@fukt.bsnet.se</email>
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<email>belorn@recompile.se</email>
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<firstname>Teddy</firstname>
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<surname>Hogeborn</surname>
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<email>teddy@fukt.bsnet.se</email>
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<email>teddy@recompile.se</email>
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<holder>Teddy Hogeborn</holder>
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<holder>Björn Påhlsson</holder>
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<arg><option>--debug</option></arg>
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<arg><option>--debuglevel
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<replaceable>LEVEL</replaceable></option></arg>
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<arg><option>--no-dbus</option></arg>
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<arg><option>--no-ipv6</option></arg>
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<arg><option>--no-restore</option></arg>
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<arg><option>--statedir
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<replaceable>DIRECTORY</replaceable></option></arg>
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<arg><option>--socket
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<replaceable>FD</replaceable></option></arg>
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<arg><option>--foreground</option></arg>
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<arg><option>--no-zeroconf</option></arg>
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<command>&COMMANDNAME;</command>
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<title>DESCRIPTION</title>
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<command>&COMMANDNAME;</command> is a server daemon which
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handles incoming request for passwords for a pre-defined list of
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client host computers. The Mandos server uses Zeroconf to
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announce itself on the local network, and uses TLS to
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communicate securely with and to authenticate the clients. The
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Mandos server uses IPv6 to allow Mandos clients to use IPv6
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link-local addresses, since the clients will probably not have
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any other addresses configured (see <xref linkend="overview"/>).
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Any authenticated client is then given the stored pre-encrypted
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password for that specific client.
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handles incoming requests for passwords for a pre-defined list
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of client host computers. For an introduction, see
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<citerefentry><refentrytitle>intro</refentrytitle>
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<manvolnum>8mandos</manvolnum></citerefentry>. The Mandos server
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uses Zeroconf to announce itself on the local network, and uses
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TLS to communicate securely with and to authenticate the
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clients. The Mandos server uses IPv6 to allow Mandos clients to
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use IPv6 link-local addresses, since the clients will probably
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not have any other addresses configured (see <xref
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linkend="overview"/>). Any authenticated client is then given
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the stored pre-encrypted password for that specific client.
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<term><option>--debuglevel
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<replaceable>LEVEL</replaceable></option></term>
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Set the debugging log level.
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<replaceable>LEVEL</replaceable> is a string, one of
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<quote><literal>CRITICAL</literal></quote>,
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<quote><literal>ERROR</literal></quote>,
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<quote><literal>WARNING</literal></quote>,
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<quote><literal>INFO</literal></quote>, or
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<quote><literal>DEBUG</literal></quote>, in order of
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increasing verbosity. The default level is
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<quote><literal>WARNING</literal></quote>.
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<term><option>--priority <replaceable>
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PRIORITY</replaceable></option></term>
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<term><option>--no-dbus</option></term>
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<xi:include href="mandos-options.xml" xpointer="dbus"/>
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See also <xref linkend="dbus_interface"/>.
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<term><option>--no-ipv6</option></term>
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<xi:include href="mandos-options.xml" xpointer="ipv6"/>
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<term><option>--no-restore</option></term>
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<xi:include href="mandos-options.xml" xpointer="restore"/>
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See also <xref linkend="persistent_state"/>.
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<term><option>--statedir
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<replaceable>DIRECTORY</replaceable></option></term>
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<xi:include href="mandos-options.xml" xpointer="statedir"/>
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<term><option>--socket
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<replaceable>FD</replaceable></option></term>
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<xi:include href="mandos-options.xml" xpointer="socket"/>
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<term><option>--foreground</option></term>
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<xi:include href="mandos-options.xml"
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xpointer="foreground"/>
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<term><option>--no-zeroconf</option></term>
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<xi:include href="mandos-options.xml" xpointer="zeroconf"/>
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start a TLS protocol handshake with a slight quirk: the Mandos
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server program acts as a TLS <quote>client</quote> while the
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connecting Mandos client acts as a TLS <quote>server</quote>.
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The Mandos client must supply an OpenPGP certificate, and the
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fingerprint of this certificate is used by the Mandos server to
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look up (in a list read from <filename>clients.conf</filename>
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at start time) which binary blob to give the client. No other
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authentication or authorization is done by the server.
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The Mandos client must supply a TLS public key, and the key ID
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of this public key is used by the Mandos server to look up (in a
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list read from <filename>clients.conf</filename> at start time)
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which binary blob to give the client. No other authentication
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or authorization is done by the server.
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<title>Mandos Protocol (Version 1)</title><tgroup cols="3"><thead>
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The server will, by default, continually check that the clients
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are still up. If a client has not been confirmed as being up
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for some time, the client is assumed to be compromised and is no
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longer eligible to receive the encrypted password. The timeout,
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checker program, and interval between checks can be configured
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both globally and per client; see <citerefentry>
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longer eligible to receive the encrypted password. (Manual
418
intervention is required to re-enable a client.) The timeout,
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extended timeout, checker program, and interval between checks
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can be configured both globally and per client; see
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<citerefentry><refentrytitle>mandos-clients.conf</refentrytitle>
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<manvolnum>5</manvolnum></citerefentry>.
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<refsect1 id="approval">
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<title>APPROVAL</title>
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The server can be configured to require manual approval for a
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client before it is sent its secret. The delay to wait for such
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approval and the default action (approve or deny) can be
432
configured both globally and per client; see <citerefentry>
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<refentrytitle>mandos-clients.conf</refentrytitle>
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<manvolnum>5</manvolnum></citerefentry>.
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<manvolnum>5</manvolnum></citerefentry>. By default all clients
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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
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optional manual denying of this specific client.
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<refsect1 id="logging">
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<title>LOGGING</title>
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The server will send log message with various severity levels to
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<filename>/dev/log</filename>. With the
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<filename class="devicefile">/dev/log</filename>. With the
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<option>--debug</option> option, it will log even more messages,
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and also show them on the console.
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<refsect1 id="persistent_state">
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<title>PERSISTENT STATE</title>
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Client settings, initially read from
460
<filename>clients.conf</filename>, are persistent across
461
restarts, and run-time changes will override settings in
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<filename>clients.conf</filename>. However, if a setting is
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<emphasis>changed</emphasis> (or a client added, or removed) in
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<filename>clients.conf</filename>, this will take precedence.
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<refsect1 id="dbus_interface">
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<title>D-BUS INTERFACE</title>
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The server will by default provide a D-Bus system bus interface.
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This interface will only be accessible by the root user or a
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Mandos-specific user, if such a user exists. For documentation
474
of the D-Bus API, see the file <filename>DBUS-API</filename>.
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<refsect1 id="exit_status">
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<title>EXIT STATUS</title>
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<term><filename>/var/run/mandos.pid</filename></term>
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The file containing the process id of
397
<command>&COMMANDNAME;</command>.
402
<term><filename>/dev/log</filename></term>
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<term><filename>/run/mandos.pid</filename></term>
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The file containing the process id of the
539
<command>&COMMANDNAME;</command> process started last.
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<emphasis >Note:</emphasis> If the <filename
541
class="directory">/run</filename> directory does not
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exist, <filename>/var/run/mandos.pid</filename> will be
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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>
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The Unix domain socket to where local syslog messages are
428
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backtrace. This could be considered a feature.
431
Currently, if a client is declared <quote>invalid</quote> due to
432
having timed out, the server does not record this fact onto
433
permanent storage. This has some security implications, see
434
<xref linkend="clients"/>.
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There is currently no way of querying the server of the current
438
status of clients, other than analyzing its <systemitem
439
class="service">syslog</systemitem> output.
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There is no fine-grained control over logging and debug output.
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Debug mode is conflated with running in the foreground.
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The console log messages do not show a time stamp.
451
This server does not check the expire time of clients’ OpenPGP
590
<xi:include href="bugs.xml"/>
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<refsect1 id="example">
466
603
<informalexample>
468
605
Run the server in debug mode, read configuration files from
469
the <filename>~/mandos</filename> directory, and use the
470
Zeroconf service name <quote>Test</quote> to not collide with
471
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:
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<title>CLIENTS</title>
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The server only gives out its stored data to clients which
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does have the OpenPGP key of the stored fingerprint. This is
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guaranteed by the fact that the client sends its OpenPGP
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public key in the TLS handshake; this ensures it to be
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genuine. The server computes the fingerprint of the key
513
itself and looks up the fingerprint in its list of
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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>
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652
<citerefentry><refentrytitle>mandos-clients.conf</refentrytitle>
516
653
<manvolnum>5</manvolnum></citerefentry>)
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654
<emphasis>must</emphasis> be made non-readable by anyone
523
660
compromised if they are gone for too long.
526
If a client is compromised, its downtime should be duly noted
527
by the server which would therefore declare the client
528
invalid. But if the server was ever restarted, it would
529
re-read its client list from its configuration file and again
530
regard all clients therein as valid, and hence eligible to
531
receive their passwords. Therefore, be careful when
532
restarting servers if it is suspected that a client has, in
533
fact, been compromised by parties who may now be running a
534
fake Mandos client with the keys from the non-encrypted
535
initial <acronym>RAM</acronym> image of the client host. What
536
should be done in that case (if restarting the server program
537
really is necessary) is to stop the server program, edit the
538
configuration file to omit any suspect clients, and restart
542
663
For more details on client-side security, see
543
664
<citerefentry><refentrytitle>mandos-client</refentrytitle>
544
665
<manvolnum>8mandos</manvolnum></citerefentry>.
549
670
<refsect1 id="see_also">
550
671
<title>SEE ALSO</title>
553
<refentrytitle>mandos-clients.conf</refentrytitle>
554
<manvolnum>5</manvolnum></citerefentry>, <citerefentry>
555
<refentrytitle>mandos.conf</refentrytitle>
556
<manvolnum>5</manvolnum></citerefentry>, <citerefentry>
557
<refentrytitle>mandos-client</refentrytitle>
558
<manvolnum>8mandos</manvolnum></citerefentry>, <citerefentry>
559
<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>
653
RFC 5081: <citetitle>Using OpenPGP Keys for Transport Layer
658
This is implemented by GnuTLS and used by this server so
659
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
added
removed
mandos.xml
