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</refsynopsisdiv>
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<refsect1 id="description">
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<title>DESCRIPTION</title>
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<command>&COMMANDNAME;</command> is a mandos plugin that works
128
like a client program that through avahi detects mandos servers,
129
sets up a gnutls connect and request a encrypted password. Any
130
passwords given is automaticly decrypted and passed to
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<command>&COMMANDNAME;</command> is a client program that
123
communicates with <citerefentry><refentrytitle
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>mandos</refentrytitle><manvolnum>8</manvolnum></citerefentry>
125
to get a password. It uses IPv6 link-local addresses to get
126
network connectivity, Zeroconf to find servers, and TLS with an
127
OpenPGP key to ensure authenticity and confidentiality. It
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keeps running, trying all servers on the network, until it
129
receives a satisfactory reply or a TERM signal is received.
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This program is not meant to be run directly; it is really meant
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to run as a plugin of the <application>Mandos</application>
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<citerefentry><refentrytitle>plugin-runner</refentrytitle>
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<manvolnum>8mandos</manvolnum></citerefentry>, which runs in the
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initial <acronym>RAM</acronym> disk environment because it is
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specified as a <quote>keyscript</quote> in the <citerefentry>
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<refentrytitle>crypttab</refentrytitle><manvolnum>5</manvolnum>
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</citerefentry> file.
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<refsect1 id="purpose">
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<title>PURPOSE</title>
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The purpose of this is to enable <emphasis>remote and unattended
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rebooting</emphasis> of client host computer with an
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<emphasis>encrypted root file system</emphasis>. See <xref
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linkend="overview"/> for details.
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<refsect1 id="options">
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<title>OPTIONS</title>
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Commonly not invoked as command lines but from configuration
139
file of plugin runner.
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This program is commonly not invoked from the command line; it
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is normally started by the <application>Mandos</application>
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plugin runner, see <citerefentry><refentrytitle
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>plugin-runner</refentrytitle><manvolnum>8mandos</manvolnum>
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</citerefentry>. Any command line options this program accepts
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are therefore normally provided by the plugin runner, and not
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<term><option>--connect=<replaceable
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>IPADDR</replaceable><literal>:</literal><replaceable
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>ADDRESS</replaceable><literal>:</literal><replaceable
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169
>PORT</replaceable></option></term>
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<replaceable>IPADDR</replaceable><literal>:</literal
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<replaceable>ADDRESS</replaceable><literal>:</literal
149
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><replaceable>PORT</replaceable></option></term>
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Connect directly to a specified mandos server
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Do not use Zeroconf to locate servers. Connect directly
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to only one specified <application>Mandos</application>
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server. Note that an IPv6 address has colon characters in
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it, so the <emphasis>last</emphasis> colon character is
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assumed to separate the address from the port number.
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<term><option>--keydir=<replaceable
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>DIRECTORY</replaceable></option></term>
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<replaceable>DIRECTORY</replaceable></option></term>
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Directory where the openpgp keyring is
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This option is normally only useful for testing and
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<term><option>--interface=
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<replaceable>NAME</replaceable></option></term>
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<term><option>--usage</option></term>
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Gives a short usage message
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Gives a short usage message.
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<term><option>--version</option></term>
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<term><option>-V</option></term>
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Prints the program version
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Prints the program version.
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<refsect1 id="overview">
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<title>OVERVIEW</title>
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<xi:include href="../overview.xml"/>
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This program is the client part. It is a plugin started by
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<citerefentry><refentrytitle>plugin-runner</refentrytitle>
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<manvolnum>8mandos</manvolnum></citerefentry> which will run in
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an initial <acronym>RAM</acronym> disk environment.
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This program could, theoretically, be used as a keyscript in
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<filename>/etc/crypttab</filename>, but it would then be
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impossible to enter a password for the encrypted root disk at
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the console, since this program does not read from the console
316
at all. This is why a separate plugin runner (<citerefentry>
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<refentrytitle>plugin-runner</refentrytitle>
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<manvolnum>8mandos</manvolnum></citerefentry>) is used to run
319
both this program and others in in parallel,
320
<emphasis>one</emphasis> of which will prompt for passwords on
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<refsect1 id="exit_status">
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<title>EXIT STATUS</title>
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This program will exit with a successful (zero) exit status if a
329
server could be found and the password received from it could be
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successfully decrypted and output on standard output. The
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program will exit with a non-zero exit status only if a critical
332
error occurs. Otherwise, it will forever connect to new
333
<application>Mandos</application> servers as they appear, trying
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to get a decryptable password and print it.
271
338
<refsect1 id="environment">
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<title>ENVIRONMENT</title>
341
This program does not use any environment variables, not even
342
the ones provided by <citerefentry><refentrytitle
343
>cryptsetup</refentrytitle><manvolnum>8</manvolnum>
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<refsect1 id="files">
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<title>FILES</title>
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<term><filename>/conf/conf.d/mandos/pubkey.txt</filename
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<term><filename>/conf/conf.d/mandos/seckey.txt</filename
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OpenPGP public and private key files, in <quote>ASCII
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Armor</quote> format. These are the default file names,
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they can be changed with the <option>--pubkey</option> and
361
<option>--seckey</option> options.
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<!-- <refsect1 id="bugs"> -->
369
<!-- <title>BUGS</title> -->
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<refsect1 id="example">
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<title>EXAMPLE</title>
377
Note that normally, command line options will not be given
378
directly, but via options for the Mandos <citerefentry
379
><refentrytitle>plugin-runner</refentrytitle>
380
<manvolnum>8mandos</manvolnum></citerefentry>.
384
Normal invocation needs no options, if the network interface
385
is <quote>eth0</quote>:
388
<userinput>&COMMANDNAME;</userinput>
393
Search for Mandos servers (and connect to them) using another
397
<!-- do not wrap this line -->
398
<userinput>&COMMANDNAME; --interface eth1</userinput>
403
Run in debug mode, and use a custom key:
407
<!-- do not wrap this line -->
408
<userinput>&COMMANDNAME; --debug --pubkey keydir/pubkey.txt --seckey keydir/seckey.txt</userinput>
414
Run in debug mode, with a custom key, and do not use Zeroconf
415
to locate a server; connect directly to the IPv6 address
416
<quote><systemitem class="ipaddress"
417
>2001:db8:f983:bd0b:30de:ae4a:71f2:f672</systemitem></quote>,
418
port 4711, using interface eth2:
422
<!-- do not wrap this line -->
423
<userinput>&COMMANDNAME; --debug --pubkey keydir/pubkey.txt --seckey keydir/seckey.txt --connect 2001:db8:f983:bd0b:30de:ae4a:71f2:f672:4711 --interface eth2</userinput>
295
429
<refsect1 id="security">
296
430
<title>SECURITY</title>
432
This program is set-uid to root, but will switch back to the
433
original (and presumably non-privileged) user and group after
434
bringing up the network interface.
437
To use this program for its intended purpose (see <xref
438
linkend="purpose"/>), the password for the root file system will
439
have to be given out to be stored in a server computer, after
440
having been encrypted using an OpenPGP key. This encrypted data
441
which will be stored in a server can only be decrypted by the
442
OpenPGP key, and the data will only be given out to those
443
clients who can prove they actually have that key. This key,
444
however, is stored unencrypted on the client side in its initial
445
<acronym>RAM</acronym> disk image file system. This is normally
446
readable by all, but this is normally fixed during installation
447
of this program; file permissions are set so that no-one is able
451
The only remaining weak point is that someone with physical
452
access to the client hard drive might turn off the client
453
computer, read the OpenPGP keys directly from the hard drive,
454
and communicate with the server. To safeguard against this, the
455
server is supposed to notice the client disappearing and stop
456
giving out the encrypted data. Therefore, it is important to
457
set the timeout and checker interval values tightly on the
458
server. See <citerefentry><refentrytitle
459
>mandos</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
462
It will also help if the checker program on the server is
463
configured to request something from the client which can not be
464
spoofed by someone else on the network, unlike unencrypted
465
<acronym>ICMP</acronym> echo (<quote>ping</quote>) replies.
468
<emphasis>Note</emphasis>: This makes it completely insecure to
469
have <application >Mandos</application> clients which dual-boot
470
to another operating system which is <emphasis>not</emphasis>
471
trusted to keep the initial <acronym>RAM</acronym> disk image
301
476
<refsect1 id="see_also">
302
477
<title>SEE ALSO</title>
479
<citerefentry><refentrytitle>cryptsetup</refentrytitle>
480
<manvolnum>8</manvolnum></citerefentry>,
481
<citerefentry><refentrytitle>crypttab</refentrytitle>
482
<manvolnum>5</manvolnum></citerefentry>,
304
483
<citerefentry><refentrytitle>mandos</refentrytitle>
305
484
<manvolnum>8</manvolnum></citerefentry>,
306
485
<citerefentry><refentrytitle>password-prompt</refentrytitle>
308
487
<citerefentry><refentrytitle>plugin-runner</refentrytitle>
309
488
<manvolnum>8mandos</manvolnum></citerefentry>
313
<ulink url="http://www.zeroconf.org/">Zeroconf</ulink>
317
<ulink url="http://www.avahi.org/">Avahi</ulink>
322
url="http://www.gnu.org/software/gnutls/">GnuTLS</ulink>
327
url="http://www.gnupg.org/related_software/gpgme/">
332
<citation>RFC 4880: <citetitle>OpenPGP Message
333
Format</citetitle></citation>
337
<citation>RFC 5081: <citetitle>Using OpenPGP Keys for
338
Transport Layer Security</citetitle></citation>
342
<citation>RFC 4291: <citetitle>IP Version 6 Addressing
343
Architecture</citetitle>, section 2.5.6, Link-Local IPv6
344
Unicast Addresses</citation>
493
<ulink url="http://www.zeroconf.org/">Zeroconf</ulink>
497
Zeroconf is the network protocol standard used for finding
498
Mandos servers on the local network.
504
<ulink url="http://www.avahi.org/">Avahi</ulink>
508
Avahi is the library this program calls to find Zeroconf
515
<ulink url="http://www.gnu.org/software/gnutls/"
520
GnuTLS is the library this client uses to implement TLS for
521
communicating securely with the server, and at the same time
522
send the public OpenPGP key to the server.
528
<ulink url="http://www.gnupg.org/related_software/gpgme/"
533
GPGME is the library used to decrypt the OpenPGP data sent
540
RFC 4291: <citetitle>IP Version 6 Addressing
541
Architecture</citetitle>
546
<term>Section 2.2: <citetitle>Text Representation of
547
Addresses</citetitle></term>
548
<listitem><para/></listitem>
551
<term>Section 2.5.5.2: <citetitle>IPv4-Mapped IPv6
552
Address</citetitle></term>
553
<listitem><para/></listitem>
556
<term>Section 2.5.6, <citetitle>Link-Local IPv6 Unicast
557
Addresses</citetitle></term>
560
This client uses IPv6 link-local addresses, which are
561
immediately usable since a link-local addresses is
562
automatically assigned to a network interfaces when it
572
RFC 4346: <citetitle>The Transport Layer Security (TLS)
573
Protocol Version 1.1</citetitle>
577
TLS 1.1 is the protocol implemented by GnuTLS.
583
RFC 4880: <citetitle>OpenPGP Message Format</citetitle>
587
The data received from the server is binary encrypted
594
RFC 5081: <citetitle>Using OpenPGP Keys for Transport Layer
599
This is implemented by GnuTLS and used by this program so
600
that OpenPGP keys can be used.
350
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<!-- Local Variables: -->
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<!-- time-stamp-start: "<!ENTITY TIMESTAMP [\"']" -->
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<!-- time-stamp-end: "[\"']>" -->