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communicates with <citerefentry><refentrytitle
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129
>mandos</refentrytitle><manvolnum>8</manvolnum></citerefentry>
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to get a password. It uses IPv6 link-local addresses to get
124
network connectivity, Zeroconf to find servers, and TLS with an
125
OpenPGP key to ensure authenticity and confidentiality. It
131
network connectivity, Zeroconf to find the server, and TLS with
132
an OpenPGP key to ensure authenticity and confidentiality. It
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133
keeps running, trying all servers on the network, until it
127
receives a satisfactory reply or a TERM signal is recieved.
134
receives a satisfactory reply.
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137
This program is not meant to be run directly; it is really meant
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330
This program could, theoretically, be used as a keyscript in
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<filename>/etc/crypttab</filename>, but it would then be
312
impossible to enter a password for the encrypted root disk at
313
the console, since this program does not read from the console
314
at all. This is why a separate plugin (<citerefentry>
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<refentrytitle>password-prompt</refentrytitle>
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<manvolnum>8mandos</manvolnum></citerefentry>) does that, which
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will be run in parallell to this one by the plugin runner.
332
impossible to enter the encrypted root disk password at the
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console, since this program does not read from the console at
334
all. This is why a separate plugin does that, which will be run
335
in parallell to this one.
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<refsect1 id="file">
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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
357
<option>--seckey</option> options.
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<!-- <refsect1 id="bugs"> -->
365
<!-- <title>BUGS</title> -->
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<refsect1 id="example">
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<title>EXAMPLE</title>
373
Note that normally, command line options will not be given
374
directly, but via options for the Mandos <citerefentry
375
><refentrytitle>plugin-runner</refentrytitle>
376
<manvolnum>8mandos</manvolnum></citerefentry>.
380
Normal invocation needs no options, if the network interface
381
is <quote>eth0</quote>:
384
<userinput>&COMMANDNAME;</userinput>
389
Search for Mandos servers on another interface:
392
<!-- do not wrap this line -->
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<userinput>&COMMANDNAME; --interface eth1</userinput>
398
Run in debug mode, and use a custom key:
402
<!-- do not wrap this line -->
403
<userinput>&COMMANDNAME; --debug --pubkey keydir/pubkey.txt --seckey keydir/seckey.txt</userinput>
409
Run in debug mode, with a custom key, and do not use Zeroconf
410
to locate a server; connect directly to the IPv6 address
411
<quote><systemitem class="ipaddress"
412
>2001:db8:f983:bd0b:30de:ae4a:71f2:f672</systemitem></quote>,
413
port 4711, using interface eth2:
417
<!-- do not wrap this line -->
418
<userinput>&COMMANDNAME; --debug --pubkey keydir/pubkey.txt --seckey keydir/seckey.txt --connect 2001:db8:f983:bd0b:30de:ae4a:71f2:f672:4711 --interface eth2</userinput>
424
380
<refsect1 id="security">
425
381
<title>SECURITY</title>
427
This program is set-uid to root, but will switch back to the
428
original (and presumably non-privileged) user and group after
429
bringing up the network interface.
432
To use this program for its intended purpose (see <xref
433
linkend="purpose"/>), the password for the root file system will
434
have to be given out to be stored in a server computer, after
435
having been encrypted using an OpenPGP key. This encrypted data
436
which will be stored in a server can only be decrypted by the
437
OpenPGP key, and the data will only be given out to those
438
clients who can prove they actually have that key. This key,
439
however, is stored unencrypted on the client side in its initial
440
<acronym>RAM</acronym> disk image file system. This is normally
441
readable by all, but this is normally fixed during installation
442
of this program; file permissions are set so that no-one is able
446
The only remaining weak point is that someone with physical
447
access to the client hard drive might turn off the client
448
computer, read the OpenPGP keys directly from the hard drive,
449
and communicate with the server. The defense against this is
450
that the server is supposed to notice the client disappearing
451
and will stop giving out the encrypted data. Therefore, it is
452
important to set the timeout and checker interval values tightly
453
on the server. See <citerefentry><refentrytitle
454
>mandos</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
457
It will also help if the checker program on the server is
458
configured to request something from the client which can not be
459
spoofed by someone else on the network, unlike unencrypted
460
<acronym>ICMP</acronym> echo (<quote>ping</quote>) replies.
463
<emphasis>Note</emphasis>: This makes it completely insecure to
464
have <application >Mandos</application> clients which dual-boot
465
to another operating system which is <emphasis>not</emphasis>
466
trusted to keep the initial <acronym>RAM</acronym> disk image
471
386
<refsect1 id="see_also">
472
387
<title>SEE ALSO</title>
474
<citerefentry><refentrytitle>cryptsetup</refentrytitle>
475
<manvolnum>8</manvolnum></citerefentry>,
476
<citerefentry><refentrytitle>crypttab</refentrytitle>
477
<manvolnum>5</manvolnum></citerefentry>,
478
389
<citerefentry><refentrytitle>mandos</refentrytitle>
479
390
<manvolnum>8</manvolnum></citerefentry>,
480
391
<citerefentry><refentrytitle>password-prompt</refentrytitle>
482
393
<citerefentry><refentrytitle>plugin-runner</refentrytitle>
483
394
<manvolnum>8mandos</manvolnum></citerefentry>
488
<ulink url="http://www.zeroconf.org/">Zeroconf</ulink>
492
Zeroconf is the network protocol standard used for finding
493
Mandos servers on the local network.
499
<ulink url="http://www.avahi.org/">Avahi</ulink>
503
Avahi is the library this program calls to find Zeroconf
510
<ulink url="http://www.gnu.org/software/gnutls/"
515
GnuTLS is the library this client uses to implement TLS for
516
communicating securely with the server, and at the same time
517
send the public OpenPGP key to the server.
523
<ulink url="http://www.gnupg.org/related_software/gpgme/"
528
GPGME is the library used to decrypt the OpenPGP data sent
535
RFC 4291: <citetitle>IP Version 6 Addressing
536
Architecture</citetitle>
541
<term>Section 2.2: <citetitle>Text Representation of
542
Addresses</citetitle></term>
543
<listitem><para/></listitem>
546
<term>Section 2.5.5.2: <citetitle>IPv4-Mapped IPv6
547
Address</citetitle></term>
548
<listitem><para/></listitem>
551
<term>Section 2.5.6, <citetitle>Link-Local IPv6 Unicast
552
Addresses</citetitle></term>
555
This client uses IPv6 link-local addresses, which are
556
immediately usable since a link-local addresses is
557
automatically assigned to a network interfaces when it
567
RFC 4346: <citetitle>The Transport Layer Security (TLS)
568
Protocol Version 1.1</citetitle>
572
TLS 1.1 is the protocol implemented by GnuTLS.
578
RFC 4880: <citetitle>OpenPGP Message Format</citetitle>
582
The data received from the server is binary encrypted
589
RFC 5081: <citetitle>Using OpenPGP Keys for Transport Layer
594
This is implemented by GnuTLS and used by this program so
595
that OpenPGP keys can be used.
398
<ulink url="http://www.zeroconf.org/">Zeroconf</ulink>
402
<ulink url="http://www.avahi.org/">Avahi</ulink>
407
url="http://www.gnu.org/software/gnutls/">GnuTLS</ulink>
412
url="http://www.gnupg.org/related_software/gpgme/"
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>