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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
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network connectivity, Zeroconf to find servers, and TLS with an
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OpenPGP key to ensure authenticity and confidentiality. It
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network connectivity, Zeroconf to find the server, and TLS with
132
an OpenPGP key to ensure authenticity and confidentiality. It
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keeps running, trying all servers on the network, until it
134
receives a satisfactory reply or a TERM signal is recieved.
134
receives a satisfactory reply.
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This program is not meant to be run directly; it is really meant
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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
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<option>--seckey</option> options.
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<!-- <refsect1 id="bugs"> -->
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<!-- <title>BUGS</title> -->
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<refsect1 id="example">
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<title>EXAMPLE</title>
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Note that normally, command line options will not be given
399
directly, but via options for the Mandos <citerefentry
400
><refentrytitle>plugin-runner</refentrytitle>
401
<manvolnum>8mandos</manvolnum></citerefentry>.
405
Normal invocation needs no options, if the network interface
406
is <quote>eth0</quote>:
409
<userinput>&COMMANDNAME;</userinput>
414
Search for Mandos servers on another interface:
417
<!-- do not wrap this line -->
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<userinput>&COMMANDNAME; --interface eth1</userinput>
423
Run in debug mode, and use a custom key directory:
426
<!-- do not wrap this line -->
427
<userinput>&COMMANDNAME; --debug --keydir keydir</userinput>
432
Run in debug mode, with a custom key directory, and do not use
433
Zeroconf to locate a server; connect directly to the IPv6
434
address <quote><systemitem class="ipaddress"
435
>2001:db8:f983:bd0b:30de:ae4a:71f2:f672</systemitem></quote>,
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port 4711, using interface eth2:
440
<!-- do not wrap this line -->
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<userinput>&COMMANDNAME; --debug --keydir keydir --connect 2001:db8:f983:bd0b:30de:ae4a:71f2:f672:4711 --interface eth2</userinput>
447
380
<refsect1 id="security">
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381
<title>SECURITY</title>
450
This program is set-uid to root, but will switch back to the
451
original (and presumably non-privileged) user and group after
452
bringing up the network interface.
455
To use this program for its intended purpose (see <xref
456
linkend="purpose"/>), the password for the root file system will
457
have to be given out to be stored in a server computer, after
458
having been encrypted using an OpenPGP key. This encrypted data
459
which will be stored in a server can only be decrypted by the
460
OpenPGP key, and the data will only be given out to those
461
clients who can prove they actually have that key. This key,
462
however, is stored unencrypted on the client side in its initial
463
<acronym>RAM</acronym> disk image file system. This is normally
464
readable by all, but this is normally fixed during installation
465
of this program; file permissions are set so that no-one is able
469
The only remaining weak point is that someone with physical
470
access to the client hard drive might turn off the client
471
computer, read the OpenPGP keys directly from the hard drive,
472
and communicate with the server. The defense against this is
473
that the server is supposed to notice the client disappearing
474
and will stop giving out the encrypted data. Therefore, it is
475
important to set the timeout and checker interval values tightly
476
on the server. See <citerefentry><refentrytitle
477
>mandos</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
480
It will also help if the checker program on the server is
481
configured to request something from the client which can not be
482
spoofed by someone else on the network, unlike unencrypted
483
<acronym>ICMP</acronym> echo (<quote>ping</quote>) replies.
486
<emphasis>Note</emphasis>: This makes it completely insecure to
487
have <application >Mandos</application> clients which dual-boot
488
to another operating system which is <emphasis>not</emphasis>
489
trusted to keep the initial <acronym>RAM</acronym> disk image
494
386
<refsect1 id="see_also">
495
387
<title>SEE ALSO</title>
497
<citerefentry><refentrytitle>cryptsetup</refentrytitle>
498
<manvolnum>8</manvolnum></citerefentry>,
499
<citerefentry><refentrytitle>crypttab</refentrytitle>
500
<manvolnum>5</manvolnum></citerefentry>,
501
389
<citerefentry><refentrytitle>mandos</refentrytitle>
502
390
<manvolnum>8</manvolnum></citerefentry>,
503
391
<citerefentry><refentrytitle>password-prompt</refentrytitle>
505
393
<citerefentry><refentrytitle>plugin-runner</refentrytitle>
506
394
<manvolnum>8mandos</manvolnum></citerefentry>
511
<ulink url="http://www.zeroconf.org/">Zeroconf</ulink>
515
Zeroconf is the network protocol standard used for finding
516
Mandos servers on the local network.
522
<ulink url="http://www.avahi.org/">Avahi</ulink>
526
Avahi is the library this program calls to find Zeroconf
533
<ulink url="http://www.gnu.org/software/gnutls/"
538
GnuTLS is the library this client uses to implement TLS for
539
communicating securely with the server, and at the same time
540
send the public OpenPGP key to the server.
546
<ulink url="http://www.gnupg.org/related_software/gpgme/"
551
GPGME is the library used to decrypt the OpenPGP data sent
558
RFC 4291: <citetitle>IP Version 6 Addressing
559
Architecture</citetitle>
564
<term>Section 2.2: <citetitle>Text Representation of
565
Addresses</citetitle></term>
566
<listitem><para/></listitem>
569
<term>Section 2.5.5.2: <citetitle>IPv4-Mapped IPv6
570
Address</citetitle></term>
571
<listitem><para/></listitem>
574
<term>Section 2.5.6, <citetitle>Link-Local IPv6 Unicast
575
Addresses</citetitle></term>
578
This client uses IPv6 link-local addresses, which are
579
immediately usable since a link-local addresses is
580
automatically assigned to a network interfaces when it
590
RFC 4346: <citetitle>The Transport Layer Security (TLS)
591
Protocol Version 1.1</citetitle>
595
TLS 1.1 is the protocol implemented by GnuTLS.
601
RFC 4880: <citetitle>OpenPGP Message Format</citetitle>
605
The data received from the server is binary encrypted
612
RFC 5081: <citetitle>Using OpenPGP Keys for Transport Layer
617
This is implemented by GnuTLS and used by this program so
618
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>