96
<option>--delay <replaceable>SECONDS</replaceable></option>
100
124
<option>--debug</option>
104
128
<command>&COMMANDNAME;</command>
105
129
<group choice="req">
106
<arg choice="plain"><option>--help</option></arg>
107
<arg choice="plain"><option>-?</option></arg>
130
<arg choice='plain'><option>--help</option></arg>
131
<arg choice='plain'><option>-?</option></arg>
111
135
<command>&COMMANDNAME;</command>
112
<arg choice="plain"><option>--usage</option></arg>
136
<arg choice='plain'><option>--usage</option></arg>
115
139
<command>&COMMANDNAME;</command>
116
140
<group choice="req">
117
<arg choice="plain"><option>--version</option></arg>
118
<arg choice="plain"><option>-V</option></arg>
141
<arg choice='plain'><option>--version</option></arg>
142
<arg choice='plain'><option>-V</option></arg>
121
145
</refsynopsisdiv>
123
147
<refsect1 id="description">
124
148
<title>DESCRIPTION</title>
126
<command>&COMMANDNAME;</command> is a client program that
127
communicates with <citerefentry><refentrytitle
128
>mandos</refentrytitle><manvolnum>8</manvolnum></citerefentry>
129
to get a password. In slightly more detail, this client program
130
brings up a network interface, uses the interface’s IPv6
131
link-local address to get network connectivity, uses Zeroconf to
132
find servers on the local network, and communicates with servers
133
using TLS with an OpenPGP key to ensure authenticity and
134
confidentiality. This client program keeps running, trying all
135
servers on the network, until it receives a satisfactory reply
136
or a TERM signal is received. If no servers are found, or after
137
all servers have been tried, it waits indefinitely for new
141
This program is not meant to be run directly; it is really meant
142
to run as a plugin of the <application>Mandos</application>
143
<citerefentry><refentrytitle>plugin-runner</refentrytitle>
144
<manvolnum>8mandos</manvolnum></citerefentry>, which runs in the
145
initial <acronym>RAM</acronym> disk environment because it is
146
specified as a <quote>keyscript</quote> in the <citerefentry>
147
<refentrytitle>crypttab</refentrytitle><manvolnum>5</manvolnum>
148
</citerefentry> file.
152
<refsect1 id="purpose">
153
<title>PURPOSE</title>
155
The purpose of this is to enable <emphasis>remote and unattended
156
rebooting</emphasis> of client host computer with an
157
<emphasis>encrypted root file system</emphasis>. See <xref
158
linkend="overview"/> for details.
150
<command>&COMMANDNAME;</command> is a mandos plugin that works
151
like a client program that through avahi detects mandos servers,
152
sets up a gnutls connect and request a encrypted password. Any
153
passwords given is automaticly decrypted and passed to
162
158
<refsect1 id="options">
163
159
<title>OPTIONS</title>
165
This program is commonly not invoked from the command line; it
166
is normally started by the <application>Mandos</application>
167
plugin runner, see <citerefentry><refentrytitle
168
>plugin-runner</refentrytitle><manvolnum>8mandos</manvolnum>
169
</citerefentry>. Any command line options this program accepts
170
are therefore normally provided by the plugin runner, and not
161
Commonly not invoked as command lines but from configuration
162
file of plugin runner.
176
167
<term><option>--connect=<replaceable
177
>ADDRESS</replaceable><literal>:</literal><replaceable
168
>IPADDR</replaceable><literal>:</literal><replaceable
178
169
>PORT</replaceable></option></term>
180
<replaceable>ADDRESS</replaceable><literal>:</literal
171
<replaceable>IPADDR</replaceable><literal>:</literal
181
172
><replaceable>PORT</replaceable></option></term>
184
Do not use Zeroconf to locate servers. Connect directly
185
to only one specified <application>Mandos</application>
186
server. Note that an IPv6 address has colon characters in
187
it, so the <emphasis>last</emphasis> colon character is
188
assumed to separate the address from the port number.
175
Connect directly to a specified mandos server
181
<term><option>--keydir=<replaceable
182
>DIRECTORY</replaceable></option></term>
184
<replaceable>DIRECTORY</replaceable></option></term>
191
This option is normally only useful for testing and
187
Directory where the openpgp keyring is
198
193
<term><option>--interface=
199
194
<replaceable>NAME</replaceable></option></term>
316
268
<term><option>--usage</option></term>
319
Gives a short usage message.
271
Gives a short usage message
325
277
<term><option>--version</option></term>
326
278
<term><option>-V</option></term>
329
Prints the program version.
281
Prints the program version
336
<refsect1 id="overview">
337
<title>OVERVIEW</title>
338
<xi:include href="../overview.xml"/>
340
This program is the client part. It is a plugin started by
341
<citerefentry><refentrytitle>plugin-runner</refentrytitle>
342
<manvolnum>8mandos</manvolnum></citerefentry> which will run in
343
an initial <acronym>RAM</acronym> disk environment.
346
This program could, theoretically, be used as a keyscript in
347
<filename>/etc/crypttab</filename>, but it would then be
348
impossible to enter a password for the encrypted root disk at
349
the console, since this program does not read from the console
350
at all. This is why a separate plugin runner (<citerefentry>
351
<refentrytitle>plugin-runner</refentrytitle>
352
<manvolnum>8mandos</manvolnum></citerefentry>) is used to run
353
both this program and others in in parallel,
354
<emphasis>one</emphasis> of which will prompt for passwords on
359
288
<refsect1 id="exit_status">
360
289
<title>EXIT STATUS</title>
362
This program will exit with a successful (zero) exit status if a
363
server could be found and the password received from it could be
364
successfully decrypted and output on standard output. The
365
program will exit with a non-zero exit status only if a critical
366
error occurs. Otherwise, it will forever connect to new
367
<application>Mandos</application> servers as they appear, trying
368
to get a decryptable password and print it.
372
294
<refsect1 id="environment">
373
295
<title>ENVIRONMENT</title>
375
This program does not use any environment variables, not even
376
the ones provided by <citerefentry><refentrytitle
377
>cryptsetup</refentrytitle><manvolnum>8</manvolnum>
382
<refsect1 id="files">
383
301
<title>FILES</title>
386
<term><filename>/conf/conf.d/mandos/pubkey.txt</filename
388
<term><filename>/conf/conf.d/mandos/seckey.txt</filename
392
OpenPGP public and private key files, in <quote>ASCII
393
Armor</quote> format. These are the default file names,
394
they can be changed with the <option>--pubkey</option> and
395
<option>--seckey</option> options.
402
<!-- <refsect1 id="bugs"> -->
403
<!-- <title>BUGS</title> -->
408
312
<refsect1 id="example">
409
313
<title>EXAMPLE</title>
411
Note that normally, command line options will not be given
412
directly, but via options for the Mandos <citerefentry
413
><refentrytitle>plugin-runner</refentrytitle>
414
<manvolnum>8mandos</manvolnum></citerefentry>.
418
Normal invocation needs no options, if the network interface
419
is <quote>eth0</quote>:
422
<userinput>&COMMANDNAME;</userinput>
427
Search for Mandos servers (and connect to them) using another
431
<!-- do not wrap this line -->
432
<userinput>&COMMANDNAME; --interface eth1</userinput>
437
Run in debug mode, and use a custom key:
441
<!-- do not wrap this line -->
442
<userinput>&COMMANDNAME; --debug --pubkey keydir/pubkey.txt --seckey keydir/seckey.txt</userinput>
448
Run in debug mode, with a custom key, and do not use Zeroconf
449
to locate a server; connect directly to the IPv6 address
450
<quote><systemitem class="ipaddress"
451
>2001:db8:f983:bd0b:30de:ae4a:71f2:f672</systemitem></quote>,
452
port 4711, using interface eth2:
456
<!-- do not wrap this line -->
457
<userinput>&COMMANDNAME; --debug --pubkey keydir/pubkey.txt --seckey keydir/seckey.txt --connect 2001:db8:f983:bd0b:30de:ae4a:71f2:f672:4711 --interface eth2</userinput>
463
318
<refsect1 id="security">
464
319
<title>SECURITY</title>
466
This program is set-uid to root, but will switch back to the
467
original (and presumably non-privileged) user and group after
468
bringing up the network interface.
471
To use this program for its intended purpose (see <xref
472
linkend="purpose"/>), the password for the root file system will
473
have to be given out to be stored in a server computer, after
474
having been encrypted using an OpenPGP key. This encrypted data
475
which will be stored in a server can only be decrypted by the
476
OpenPGP key, and the data will only be given out to those
477
clients who can prove they actually have that key. This key,
478
however, is stored unencrypted on the client side in its initial
479
<acronym>RAM</acronym> disk image file system. This is normally
480
readable by all, but this is normally fixed during installation
481
of this program; file permissions are set so that no-one is able
485
The only remaining weak point is that someone with physical
486
access to the client hard drive might turn off the client
487
computer, read the OpenPGP keys directly from the hard drive,
488
and communicate with the server. To safeguard against this, the
489
server is supposed to notice the client disappearing and stop
490
giving out the encrypted data. Therefore, it is important to
491
set the timeout and checker interval values tightly on the
492
server. See <citerefentry><refentrytitle
493
>mandos</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
496
It will also help if the checker program on the server is
497
configured to request something from the client which can not be
498
spoofed by someone else on the network, unlike unencrypted
499
<acronym>ICMP</acronym> echo (<quote>ping</quote>) replies.
502
<emphasis>Note</emphasis>: This makes it completely insecure to
503
have <application >Mandos</application> clients which dual-boot
504
to another operating system which is <emphasis>not</emphasis>
505
trusted to keep the initial <acronym>RAM</acronym> disk image
510
324
<refsect1 id="see_also">
511
325
<title>SEE ALSO</title>
513
<citerefentry><refentrytitle>cryptsetup</refentrytitle>
514
<manvolnum>8</manvolnum></citerefentry>,
515
<citerefentry><refentrytitle>crypttab</refentrytitle>
516
<manvolnum>5</manvolnum></citerefentry>,
517
327
<citerefentry><refentrytitle>mandos</refentrytitle>
518
328
<manvolnum>8</manvolnum></citerefentry>,
519
329
<citerefentry><refentrytitle>password-prompt</refentrytitle>
521
331
<citerefentry><refentrytitle>plugin-runner</refentrytitle>
522
332
<manvolnum>8mandos</manvolnum></citerefentry>
527
<ulink url="http://www.zeroconf.org/">Zeroconf</ulink>
531
Zeroconf is the network protocol standard used for finding
532
Mandos servers on the local network.
538
<ulink url="http://www.avahi.org/">Avahi</ulink>
542
Avahi is the library this program calls to find Zeroconf
549
<ulink url="http://www.gnu.org/software/gnutls/"
554
GnuTLS is the library this client uses to implement TLS for
555
communicating securely with the server, and at the same time
556
send the public OpenPGP key to the server.
562
<ulink url="http://www.gnupg.org/related_software/gpgme/"
567
GPGME is the library used to decrypt the OpenPGP data sent
574
RFC 4291: <citetitle>IP Version 6 Addressing
575
Architecture</citetitle>
580
<term>Section 2.2: <citetitle>Text Representation of
581
Addresses</citetitle></term>
582
<listitem><para/></listitem>
585
<term>Section 2.5.5.2: <citetitle>IPv4-Mapped IPv6
586
Address</citetitle></term>
587
<listitem><para/></listitem>
590
<term>Section 2.5.6, <citetitle>Link-Local IPv6 Unicast
591
Addresses</citetitle></term>
594
This client uses IPv6 link-local addresses, which are
595
immediately usable since a link-local addresses is
596
automatically assigned to a network interfaces when it
606
RFC 4346: <citetitle>The Transport Layer Security (TLS)
607
Protocol Version 1.1</citetitle>
611
TLS 1.1 is the protocol implemented by GnuTLS.
617
RFC 4880: <citetitle>OpenPGP Message Format</citetitle>
621
The data received from the server is binary encrypted
628
RFC 5081: <citetitle>Using OpenPGP Keys for Transport Layer
633
This is implemented by GnuTLS and used by this program so
634
that OpenPGP keys can be used.
336
<ulink url="http://www.zeroconf.org/">Zeroconf</ulink>
340
<ulink url="http://www.avahi.org/">Avahi</ulink>
345
url="http://www.gnu.org/software/gnutls/">GnuTLS</ulink>
350
url="http://www.gnupg.org/related_software/gpgme/">
355
<citation>RFC 4880: <citetitle>OpenPGP Message
356
Format</citetitle></citation>
360
<citation>RFC 5081: <citetitle>Using OpenPGP Keys for
361
Transport Layer Security</citetitle></citation>
365
<citation>RFC 4291: <citetitle>IP Version 6 Addressing
366
Architecture</citetitle>, section 2.5.6, Link-Local IPv6
367
Unicast Addresses</citation>
642
373
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