67
48
<refname><command>&COMMANDNAME;</command></refname>
50
Client for <application>Mandos</application>
75
56
<command>&COMMANDNAME;</command>
76
<arg choice='opt'>--connect<arg choice='plain'>IP</arg></arg>
77
<arg choice='opt'>--keydir<arg choice='plain'>KEYDIR</arg></arg>
78
<arg choice='opt'>--interface<arg choice='plain'>INTERFACE</arg></arg>
79
<arg choice='opt'>--pubkey<arg choice='plain'>PUBKEY</arg></arg>
80
<arg choice='opt'>--seckey<arg choice='plain'>SECKEY</arg></arg>
81
<arg choice='opt'>--priority<arg choice='plain'>PRIORITY</arg></arg>
82
<arg choice='opt'>--dh-bits<arg choice='plain'>BITS</arg></arg>
83
<arg choice='opt'>--debug</arg>
86
<command>&COMMANDNAME;</command>
87
<arg choice='plain'>--help</arg>
90
<command>&COMMANDNAME;</command>
91
<arg choice='plain'>--usage</arg>
94
<command>&COMMANDNAME;</command>
95
<arg choice='plain'>--version</arg>
58
<arg choice="plain"><option>--connect
59
<replaceable>ADDRESS</replaceable><literal>:</literal
60
><replaceable>PORT</replaceable></option></arg>
61
<arg choice="plain"><option>-c
62
<replaceable>ADDRESS</replaceable><literal>:</literal
63
><replaceable>PORT</replaceable></option></arg>
67
<arg choice="plain"><option>--interface
68
<replaceable>NAME</replaceable></option></arg>
69
<arg choice="plain"><option>-i
70
<replaceable>NAME</replaceable></option></arg>
74
<arg choice="plain"><option>--pubkey
75
<replaceable>FILE</replaceable></option></arg>
76
<arg choice="plain"><option>-p
77
<replaceable>FILE</replaceable></option></arg>
81
<arg choice="plain"><option>--seckey
82
<replaceable>FILE</replaceable></option></arg>
83
<arg choice="plain"><option>-s
84
<replaceable>FILE</replaceable></option></arg>
88
<option>--priority <replaceable>STRING</replaceable></option>
92
<option>--dh-bits <replaceable>BITS</replaceable></option>
96
<option>--debug</option>
100
<command>&COMMANDNAME;</command>
102
<arg choice="plain"><option>--help</option></arg>
103
<arg choice="plain"><option>-?</option></arg>
107
<command>&COMMANDNAME;</command>
108
<arg choice="plain"><option>--usage</option></arg>
111
<command>&COMMANDNAME;</command>
113
<arg choice="plain"><option>--version</option></arg>
114
<arg choice="plain"><option>-V</option></arg>
99
119
<refsect1 id="description">
100
120
<title>DESCRIPTION</title>
102
<command>&COMMANDNAME;</command> is a mandos plugin that works
103
like a client program that through avahi detects mandos servers,
104
sets up a gnutls connect and request a encrypted password. Any
105
passwords given is automaticly decrypted and passed to
122
<command>&COMMANDNAME;</command> is a client program that
123
communicates with <citerefentry><refentrytitle
124
>mandos</refentrytitle><manvolnum>8</manvolnum></citerefentry>
125
to get a password. It brings up a network interface, uses its
126
IPv6 link-local address to get network connectivity, uses
127
Zeroconf to find servers, and uses TLS with an OpenPGP key to
128
ensure authenticity and confidentiality. It keeps running,
129
trying all servers on the network, until it receives a
130
satisfactory reply or a TERM signal is received.
133
This program is not meant to be run directly; it is really meant
134
to run as a plugin of the <application>Mandos</application>
135
<citerefentry><refentrytitle>plugin-runner</refentrytitle>
136
<manvolnum>8mandos</manvolnum></citerefentry>, which runs in the
137
initial <acronym>RAM</acronym> disk environment because it is
138
specified as a <quote>keyscript</quote> in the <citerefentry>
139
<refentrytitle>crypttab</refentrytitle><manvolnum>5</manvolnum>
140
</citerefentry> file.
144
<refsect1 id="purpose">
145
<title>PURPOSE</title>
147
The purpose of this is to enable <emphasis>remote and unattended
148
rebooting</emphasis> of client host computer with an
149
<emphasis>encrypted root file system</emphasis>. See <xref
150
linkend="overview"/> for details.
110
154
<refsect1 id="options">
111
155
<title>OPTIONS</title>
113
Commonly not invoked as command lines but from configuration
114
file of plugin runner.
157
This program is commonly not invoked from the command line; it
158
is normally started by the <application>Mandos</application>
159
plugin runner, see <citerefentry><refentrytitle
160
>plugin-runner</refentrytitle><manvolnum>8mandos</manvolnum>
161
</citerefentry>. Any command line options this program accepts
162
are therefore normally provided by the plugin runner, and not
119
<term><literal>-c</literal>, <literal>--connect=<replaceable>
120
IP</replaceable></literal></term>
123
Connect directly to a specified mandos server
129
<term><literal>-d</literal>, <literal>--keydir=<replaceable>
130
KEYDIR</replaceable></literal></term>
133
Directory where the openpgp keyring is
139
<term><literal>-i</literal>, <literal>--interface=
140
<replaceable>INTERFACE</replaceable></literal></term>
143
Interface that Avahi will conntect through
149
<term><literal>-p</literal>, <literal>--pubkey=<replaceable>
150
PUBKEY</replaceable></literal></term>
153
Public openpgp key for gnutls authentication
159
<term><literal>-s</literal>, <literal>--seckey=<replaceable>
160
SECKEY</replaceable></literal></term>
163
Secret openpgp key for gnutls authentication
169
<term><literal>--priority=<replaceable>PRIORITY</replaceable>
179
<term><literal>--dh-bits=<replaceable>BITS</replaceable>
183
dh-bits to use in gnutls communication
189
<term><literal>--debug</literal></term>
198
<term><literal>-?</literal>, <literal>--help</literal></term>
207
<term><literal>--usage</literal></term>
210
Gives a short usage message
216
<term><literal>-V</literal>, <literal>--version</literal></term>
219
Prints the program version
168
<term><option>--connect=<replaceable
169
>ADDRESS</replaceable><literal>:</literal><replaceable
170
>PORT</replaceable></option></term>
172
<replaceable>ADDRESS</replaceable><literal>:</literal
173
><replaceable>PORT</replaceable></option></term>
176
Do not use Zeroconf to locate servers. Connect directly
177
to only one specified <application>Mandos</application>
178
server. Note that an IPv6 address has colon characters in
179
it, so the <emphasis>last</emphasis> colon character is
180
assumed to separate the address from the port number.
183
This option is normally only useful for testing and
190
<term><option>--interface=
191
<replaceable>NAME</replaceable></option></term>
193
<replaceable>NAME</replaceable></option></term>
196
Network interface that will be brought up and scanned for
197
Mandos servers to connect to. The default it
198
<quote><literal>eth0</literal></quote>.
201
If the <option>--connect</option> option is used, this
202
specifies the interface to use to connect to the address
209
<term><option>--pubkey=<replaceable
210
>FILE</replaceable></option></term>
212
<replaceable>FILE</replaceable></option></term>
215
OpenPGP public key file name. The default name is
216
<quote><filename>/conf/conf.d/mandos/pubkey.txt</filename
223
<term><option>--seckey=<replaceable
224
>FILE</replaceable></option></term>
226
<replaceable>FILE</replaceable></option></term>
229
OpenPGP secret key file name. The default name is
230
<quote><filename>/conf/conf.d/mandos/seckey.txt</filename
237
<term><option>--priority=<replaceable
238
>STRING</replaceable></option></term>
240
<xi:include href="../mandos-options.xml"
241
xpointer="priority"/>
246
<term><option>--dh-bits=<replaceable
247
>BITS</replaceable></option></term>
250
Sets the number of bits to use for the prime number in the
251
TLS Diffie-Hellman key exchange. Default is 1024.
257
<term><option>--debug</option></term>
260
Enable debug mode. This will enable a lot of output to
261
standard error about what the program is doing. The
262
program will still perform all other functions normally.
265
It will also enable debug mode in the Avahi and GnuTLS
266
libraries, making them print large amounts of debugging
273
<term><option>--help</option></term>
274
<term><option>-?</option></term>
277
Gives a help message about options and their meanings.
283
<term><option>--usage</option></term>
286
Gives a short usage message.
292
<term><option>--version</option></term>
293
<term><option>-V</option></term>
296
Prints the program version.
303
<refsect1 id="overview">
304
<title>OVERVIEW</title>
305
<xi:include href="../overview.xml"/>
307
This program is the client part. It is a plugin started by
308
<citerefentry><refentrytitle>plugin-runner</refentrytitle>
309
<manvolnum>8mandos</manvolnum></citerefentry> which will run in
310
an initial <acronym>RAM</acronym> disk environment.
313
This program could, theoretically, be used as a keyscript in
314
<filename>/etc/crypttab</filename>, but it would then be
315
impossible to enter a password for the encrypted root disk at
316
the console, since this program does not read from the console
317
at all. This is why a separate plugin runner (<citerefentry>
318
<refentrytitle>plugin-runner</refentrytitle>
319
<manvolnum>8mandos</manvolnum></citerefentry>) is used to run
320
both this program and others in in parallel,
321
<emphasis>one</emphasis> of which will prompt for passwords on
226
326
<refsect1 id="exit_status">
227
327
<title>EXIT STATUS</title>
329
This program will exit with a successful (zero) exit status if a
330
server could be found and the password received from it could be
331
successfully decrypted and output on standard output. The
332
program will exit with a non-zero exit status only if a critical
333
error occurs. Otherwise, it will forever connect to new
334
<application>Mandos</application> servers as they appear, trying
335
to get a decryptable password and print it.
232
339
<refsect1 id="environment">
233
340
<title>ENVIRONMENT</title>
342
This program does not use any environment variables, not even
343
the ones provided by <citerefentry><refentrytitle
344
>cryptsetup</refentrytitle><manvolnum>8</manvolnum>
349
<refsect1 id="files">
239
350
<title>FILES</title>
353
<term><filename>/conf/conf.d/mandos/pubkey.txt</filename
355
<term><filename>/conf/conf.d/mandos/seckey.txt</filename
359
OpenPGP public and private key files, in <quote>ASCII
360
Armor</quote> format. These are the default file names,
361
they can be changed with the <option>--pubkey</option> and
362
<option>--seckey</option> options.
369
<!-- <refsect1 id="bugs"> -->
370
<!-- <title>BUGS</title> -->
250
375
<refsect1 id="example">
251
376
<title>EXAMPLE</title>
378
Note that normally, command line options will not be given
379
directly, but via options for the Mandos <citerefentry
380
><refentrytitle>plugin-runner</refentrytitle>
381
<manvolnum>8mandos</manvolnum></citerefentry>.
385
Normal invocation needs no options, if the network interface
386
is <quote>eth0</quote>:
389
<userinput>&COMMANDNAME;</userinput>
394
Search for Mandos servers (and connect to them) using another
398
<!-- do not wrap this line -->
399
<userinput>&COMMANDNAME; --interface eth1</userinput>
404
Run in debug mode, and use a custom key:
408
<!-- do not wrap this line -->
409
<userinput>&COMMANDNAME; --debug --pubkey keydir/pubkey.txt --seckey keydir/seckey.txt</userinput>
415
Run in debug mode, with a custom key, and do not use Zeroconf
416
to locate a server; connect directly to the IPv6 address
417
<quote><systemitem class="ipaddress"
418
>2001:db8:f983:bd0b:30de:ae4a:71f2:f672</systemitem></quote>,
419
port 4711, using interface eth2:
423
<!-- do not wrap this line -->
424
<userinput>&COMMANDNAME; --debug --pubkey keydir/pubkey.txt --seckey keydir/seckey.txt --connect 2001:db8:f983:bd0b:30de:ae4a:71f2:f672:4711 --interface eth2</userinput>
256
430
<refsect1 id="security">
257
431
<title>SECURITY</title>
433
This program is set-uid to root, but will switch back to the
434
original (and presumably non-privileged) user and group after
435
bringing up the network interface.
438
To use this program for its intended purpose (see <xref
439
linkend="purpose"/>), the password for the root file system will
440
have to be given out to be stored in a server computer, after
441
having been encrypted using an OpenPGP key. This encrypted data
442
which will be stored in a server can only be decrypted by the
443
OpenPGP key, and the data will only be given out to those
444
clients who can prove they actually have that key. This key,
445
however, is stored unencrypted on the client side in its initial
446
<acronym>RAM</acronym> disk image file system. This is normally
447
readable by all, but this is normally fixed during installation
448
of this program; file permissions are set so that no-one is able
452
The only remaining weak point is that someone with physical
453
access to the client hard drive might turn off the client
454
computer, read the OpenPGP keys directly from the hard drive,
455
and communicate with the server. To safeguard against this, the
456
server is supposed to notice the client disappearing and stop
457
giving out the encrypted data. Therefore, it is important to
458
set the timeout and checker interval values tightly on the
459
server. See <citerefentry><refentrytitle
460
>mandos</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
463
It will also help if the checker program on the server is
464
configured to request something from the client which can not be
465
spoofed by someone else on the network, unlike unencrypted
466
<acronym>ICMP</acronym> echo (<quote>ping</quote>) replies.
469
<emphasis>Note</emphasis>: This makes it completely insecure to
470
have <application >Mandos</application> clients which dual-boot
471
to another operating system which is <emphasis>not</emphasis>
472
trusted to keep the initial <acronym>RAM</acronym> disk image
262
477
<refsect1 id="see_also">
263
478
<title>SEE ALSO</title>
266
<citerefentry><refentrytitle>mandos</refentrytitle>
267
<manvolnum>8</manvolnum></citerefentry>
271
<citerefentry><refentrytitle>plugin-runner</refentrytitle>
272
<manvolnum>8mandos</manvolnum></citerefentry>
276
<citerefentry><refentrytitle>password-prompt</refentrytitle>
277
<manvolnum>8mandos</manvolnum></citerefentry>
281
<ulink url="http://www.zeroconf.org/">Zeroconf</ulink>
285
<ulink url="http://www.avahi.org/">Avahi</ulink>
290
url="http://www.gnu.org/software/gnutls/">GnuTLS</ulink>
295
url="http://www.gnupg.org/related_software/gpgme/">
300
<citation>RFC 4880: <citetitle>OpenPGP Message
301
Format</citetitle></citation>
305
<citation>RFC 5081: <citetitle>Using OpenPGP Keys for
306
Transport Layer Security</citetitle></citation>
310
<citation>RFC 4291: <citetitle>IP Version 6 Addressing
311
Architecture</citetitle>, section 2.5.6, Link-Local IPv6
312
Unicast Addresses</citation>
480
<citerefentry><refentrytitle>cryptsetup</refentrytitle>
481
<manvolnum>8</manvolnum></citerefentry>,
482
<citerefentry><refentrytitle>crypttab</refentrytitle>
483
<manvolnum>5</manvolnum></citerefentry>,
484
<citerefentry><refentrytitle>mandos</refentrytitle>
485
<manvolnum>8</manvolnum></citerefentry>,
486
<citerefentry><refentrytitle>password-prompt</refentrytitle>
487
<manvolnum>8mandos</manvolnum></citerefentry>,
488
<citerefentry><refentrytitle>plugin-runner</refentrytitle>
489
<manvolnum>8mandos</manvolnum></citerefentry>
494
<ulink url="http://www.zeroconf.org/">Zeroconf</ulink>
498
Zeroconf is the network protocol standard used for finding
499
Mandos servers on the local network.
505
<ulink url="http://www.avahi.org/">Avahi</ulink>
509
Avahi is the library this program calls to find Zeroconf
516
<ulink url="http://www.gnu.org/software/gnutls/"
521
GnuTLS is the library this client uses to implement TLS for
522
communicating securely with the server, and at the same time
523
send the public OpenPGP key to the server.
529
<ulink url="http://www.gnupg.org/related_software/gpgme/"
534
GPGME is the library used to decrypt the OpenPGP data sent
541
RFC 4291: <citetitle>IP Version 6 Addressing
542
Architecture</citetitle>
547
<term>Section 2.2: <citetitle>Text Representation of
548
Addresses</citetitle></term>
549
<listitem><para/></listitem>
552
<term>Section 2.5.5.2: <citetitle>IPv4-Mapped IPv6
553
Address</citetitle></term>
554
<listitem><para/></listitem>
557
<term>Section 2.5.6, <citetitle>Link-Local IPv6 Unicast
558
Addresses</citetitle></term>
561
This client uses IPv6 link-local addresses, which are
562
immediately usable since a link-local addresses is
563
automatically assigned to a network interfaces when it
573
RFC 4346: <citetitle>The Transport Layer Security (TLS)
574
Protocol Version 1.1</citetitle>
578
TLS 1.1 is the protocol implemented by GnuTLS.
584
RFC 4880: <citetitle>OpenPGP Message Format</citetitle>
588
The data received from the server is binary encrypted
595
RFC 5081: <citetitle>Using OpenPGP Keys for Transport Layer
600
This is implemented by GnuTLS and used by this program so
601
that OpenPGP keys can be used.
609
<!-- Local Variables: -->
610
<!-- time-stamp-start: "<!ENTITY TIMESTAMP [\"']" -->
611
<!-- time-stamp-end: "[\"']>" -->
612
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