146
115
</refsynopsisdiv>
148
117
<refsect1 id="description">
149
118
<title>DESCRIPTION</title>
151
<command>&COMMANDNAME;</command> is a mandos plugin that works
152
like a client program that through avahi detects mandos servers,
153
sets up a gnutls connect and request a encrypted password. Any
154
passwords given is automaticly decrypted and passed to
120
<command>&COMMANDNAME;</command> is a client program that
121
communicates with <citerefentry><refentrytitle
122
>mandos</refentrytitle><manvolnum>8</manvolnum></citerefentry>
123
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
126
keeps running, trying all servers on the network, until it
127
receives a satisfactory reply or a TERM signal is received.
130
This program is not meant to be run directly; it is really meant
131
to run as a plugin of the <application>Mandos</application>
132
<citerefentry><refentrytitle>plugin-runner</refentrytitle>
133
<manvolnum>8mandos</manvolnum></citerefentry>, which runs in the
134
initial <acronym>RAM</acronym> disk environment because it is
135
specified as a <quote>keyscript</quote> in the <citerefentry>
136
<refentrytitle>crypttab</refentrytitle><manvolnum>5</manvolnum>
137
</citerefentry> file.
141
<refsect1 id="purpose">
142
<title>PURPOSE</title>
144
The purpose of this is to enable <emphasis>remote and unattended
145
rebooting</emphasis> of client host computer with an
146
<emphasis>encrypted root file system</emphasis>. See <xref
147
linkend="overview"/> for details.
159
151
<refsect1 id="options">
160
152
<title>OPTIONS</title>
162
Commonly not invoked as command lines but from configuration
163
file of plugin runner.
154
This program is commonly not invoked from the command line; it
155
is normally started by the <application>Mandos</application>
156
plugin runner, see <citerefentry><refentrytitle
157
>plugin-runner</refentrytitle><manvolnum>8mandos</manvolnum>
158
</citerefentry>. Any command line options this program accepts
159
are therefore normally provided by the plugin runner, and not
168
165
<term><option>--connect=<replaceable
169
>IPADDR</replaceable><literal>:</literal><replaceable
166
>ADDRESS</replaceable><literal>:</literal><replaceable
170
167
>PORT</replaceable></option></term>
172
<replaceable>IPADDR</replaceable><literal>:</literal
169
<replaceable>ADDRESS</replaceable><literal>:</literal
173
170
><replaceable>PORT</replaceable></option></term>
176
Connect directly to a specified mandos server
173
Do not use Zeroconf to locate servers. Connect directly
174
to only one specified <application>Mandos</application>
175
server. Note that an IPv6 address has colon characters in
176
it, so the <emphasis>last</emphasis> colon character is
177
assumed to separate the address from the port number.
182
<term><option>--keydir=<replaceable
183
>DIRECTORY</replaceable></option></term>
185
<replaceable>DIRECTORY</replaceable></option></term>
188
Directory where the openpgp keyring is
180
This option is normally only useful for testing and
194
187
<term><option>--interface=
195
188
<replaceable>NAME</replaceable></option></term>
269
280
<term><option>--usage</option></term>
272
Gives a short usage message
283
Gives a short usage message.
278
289
<term><option>--version</option></term>
279
290
<term><option>-V</option></term>
282
Prints the program version
293
Prints the program version.
300
<refsect1 id="overview">
301
<title>OVERVIEW</title>
302
<xi:include href="../overview.xml"/>
304
This program is the client part. It is a plugin started by
305
<citerefentry><refentrytitle>plugin-runner</refentrytitle>
306
<manvolnum>8mandos</manvolnum></citerefentry> which will run in
307
an initial <acronym>RAM</acronym> disk environment.
310
This program could, theoretically, be used as a keyscript in
311
<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 runner (<citerefentry>
315
<refentrytitle>plugin-runner</refentrytitle>
316
<manvolnum>8mandos</manvolnum></citerefentry>) is used to run
317
both this program and others in in parallel,
318
<emphasis>one</emphasis> of which will prompt for passwords on
289
323
<refsect1 id="exit_status">
290
324
<title>EXIT STATUS</title>
326
This program will exit with a successful (zero) exit status if a
327
server could be found and the password received from it could be
328
successfully decrypted and output on standard output. The
329
program will exit with a non-zero exit status only if a critical
330
error occurs. Otherwise, it will forever connect to new
331
<application>Mandos</application> servers as they appear, trying
332
to get a decryptable password and print it.
295
336
<refsect1 id="environment">
296
337
<title>ENVIRONMENT</title>
339
This program does not use any environment variables, not even
340
the ones provided by <citerefentry><refentrytitle
341
>cryptsetup</refentrytitle><manvolnum>8</manvolnum>
301
346
<refsect1 id="file">
302
347
<title>FILES</title>
350
<term><filename>/conf/conf.d/mandos/pubkey.txt</filename
352
<term><filename>/conf/conf.d/mandos/seckey.txt</filename
356
OpenPGP public and private key files, in <quote>ASCII
357
Armor</quote> format. These are the default file names,
358
they can be changed with the <option>--pubkey</option> and
359
<option>--seckey</option> options.
366
<!-- <refsect1 id="bugs"> -->
367
<!-- <title>BUGS</title> -->
313
372
<refsect1 id="example">
314
373
<title>EXAMPLE</title>
375
Note that normally, command line options will not be given
376
directly, but via options for the Mandos <citerefentry
377
><refentrytitle>plugin-runner</refentrytitle>
378
<manvolnum>8mandos</manvolnum></citerefentry>.
382
Normal invocation needs no options, if the network interface
383
is <quote>eth0</quote>:
386
<userinput>&COMMANDNAME;</userinput>
391
Search for Mandos servers (and connect to them) using another
395
<!-- do not wrap this line -->
396
<userinput>&COMMANDNAME; --interface eth1</userinput>
401
Run in debug mode, and use a custom key:
405
<!-- do not wrap this line -->
406
<userinput>&COMMANDNAME; --debug --pubkey keydir/pubkey.txt --seckey keydir/seckey.txt</userinput>
412
Run in debug mode, with a custom key, and do not use Zeroconf
413
to locate a server; connect directly to the IPv6 address
414
<quote><systemitem class="ipaddress"
415
>2001:db8:f983:bd0b:30de:ae4a:71f2:f672</systemitem></quote>,
416
port 4711, using interface eth2:
420
<!-- do not wrap this line -->
421
<userinput>&COMMANDNAME; --debug --pubkey keydir/pubkey.txt --seckey keydir/seckey.txt --connect 2001:db8:f983:bd0b:30de:ae4a:71f2:f672:4711 --interface eth2</userinput>
319
427
<refsect1 id="security">
320
428
<title>SECURITY</title>
430
This program is set-uid to root, but will switch back to the
431
original (and presumably non-privileged) user and group after
432
bringing up the network interface.
435
To use this program for its intended purpose (see <xref
436
linkend="purpose"/>), the password for the root file system will
437
have to be given out to be stored in a server computer, after
438
having been encrypted using an OpenPGP key. This encrypted data
439
which will be stored in a server can only be decrypted by the
440
OpenPGP key, and the data will only be given out to those
441
clients who can prove they actually have that key. This key,
442
however, is stored unencrypted on the client side in its initial
443
<acronym>RAM</acronym> disk image file system. This is normally
444
readable by all, but this is normally fixed during installation
445
of this program; file permissions are set so that no-one is able
449
The only remaining weak point is that someone with physical
450
access to the client hard drive might turn off the client
451
computer, read the OpenPGP keys directly from the hard drive,
452
and communicate with the server. To safeguard against this, the
453
server is supposed to notice the client disappearing and stop
454
giving out the encrypted data. Therefore, it is important to
455
set the timeout and checker interval values tightly on the
456
server. See <citerefentry><refentrytitle
457
>mandos</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
460
It will also help if the checker program on the server is
461
configured to request something from the client which can not be
462
spoofed by someone else on the network, unlike unencrypted
463
<acronym>ICMP</acronym> echo (<quote>ping</quote>) replies.
466
<emphasis>Note</emphasis>: This makes it completely insecure to
467
have <application >Mandos</application> clients which dual-boot
468
to another operating system which is <emphasis>not</emphasis>
469
trusted to keep the initial <acronym>RAM</acronym> disk image
325
474
<refsect1 id="see_also">
326
475
<title>SEE ALSO</title>
477
<citerefentry><refentrytitle>cryptsetup</refentrytitle>
478
<manvolnum>8</manvolnum></citerefentry>,
479
<citerefentry><refentrytitle>crypttab</refentrytitle>
480
<manvolnum>5</manvolnum></citerefentry>,
328
481
<citerefentry><refentrytitle>mandos</refentrytitle>
329
482
<manvolnum>8</manvolnum></citerefentry>,
330
483
<citerefentry><refentrytitle>password-prompt</refentrytitle>
332
485
<citerefentry><refentrytitle>plugin-runner</refentrytitle>
333
486
<manvolnum>8mandos</manvolnum></citerefentry>
337
<ulink url="http://www.zeroconf.org/">Zeroconf</ulink>
341
<ulink url="http://www.avahi.org/">Avahi</ulink>
346
url="http://www.gnu.org/software/gnutls/">GnuTLS</ulink>
351
url="http://www.gnupg.org/related_software/gpgme/">
356
<citation>RFC 4880: <citetitle>OpenPGP Message
357
Format</citetitle></citation>
361
<citation>RFC 5081: <citetitle>Using OpenPGP Keys for
362
Transport Layer Security</citetitle></citation>
366
<citation>RFC 4291: <citetitle>IP Version 6 Addressing
367
Architecture</citetitle>, section 2.5.6, Link-Local IPv6
368
Unicast Addresses</citation>
491
<ulink url="http://www.zeroconf.org/">Zeroconf</ulink>
495
Zeroconf is the network protocol standard used for finding
496
Mandos servers on the local network.
502
<ulink url="http://www.avahi.org/">Avahi</ulink>
506
Avahi is the library this program calls to find Zeroconf
513
<ulink url="http://www.gnu.org/software/gnutls/"
518
GnuTLS is the library this client uses to implement TLS for
519
communicating securely with the server, and at the same time
520
send the public OpenPGP key to the server.
526
<ulink url="http://www.gnupg.org/related_software/gpgme/"
531
GPGME is the library used to decrypt the OpenPGP data sent
538
RFC 4291: <citetitle>IP Version 6 Addressing
539
Architecture</citetitle>
544
<term>Section 2.2: <citetitle>Text Representation of
545
Addresses</citetitle></term>
546
<listitem><para/></listitem>
549
<term>Section 2.5.5.2: <citetitle>IPv4-Mapped IPv6
550
Address</citetitle></term>
551
<listitem><para/></listitem>
554
<term>Section 2.5.6, <citetitle>Link-Local IPv6 Unicast
555
Addresses</citetitle></term>
558
This client uses IPv6 link-local addresses, which are
559
immediately usable since a link-local addresses is
560
automatically assigned to a network interfaces when it
570
RFC 4346: <citetitle>The Transport Layer Security (TLS)
571
Protocol Version 1.1</citetitle>
575
TLS 1.1 is the protocol implemented by GnuTLS.
581
RFC 4880: <citetitle>OpenPGP Message Format</citetitle>
585
The data received from the server is binary encrypted
592
RFC 5081: <citetitle>Using OpenPGP Keys for Transport Layer
597
This is implemented by GnuTLS and used by this program so
598
that OpenPGP keys can be used.
374
606
<!-- Local Variables: -->
375
607
<!-- time-stamp-start: "<!ENTITY TIMESTAMP [\"']" -->
376
608
<!-- time-stamp-end: "[\"']>" -->