46
67
<refname><command>&COMMANDNAME;</command></refname>
48
Client for <application>Mandos</application>
54
75
<command>&COMMANDNAME;</command>
56
<arg choice="plain"><option>--connect
57
<replaceable>ADDRESS</replaceable><literal>:</literal
58
><replaceable>PORT</replaceable></option></arg>
59
<arg choice="plain"><option>-c
60
<replaceable>ADDRESS</replaceable><literal>:</literal
61
><replaceable>PORT</replaceable></option></arg>
65
<arg choice="plain"><option>--interface
66
<replaceable>NAME</replaceable></option></arg>
67
<arg choice="plain"><option>-i
68
<replaceable>NAME</replaceable></option></arg>
72
<arg choice="plain"><option>--pubkey
73
<replaceable>FILE</replaceable></option></arg>
74
<arg choice="plain"><option>-p
75
<replaceable>FILE</replaceable></option></arg>
79
<arg choice="plain"><option>--seckey
80
<replaceable>FILE</replaceable></option></arg>
81
<arg choice="plain"><option>-s
82
<replaceable>FILE</replaceable></option></arg>
86
<option>--priority <replaceable>STRING</replaceable></option>
90
<option>--dh-bits <replaceable>BITS</replaceable></option>
94
<option>--debug</option>
98
<command>&COMMANDNAME;</command>
100
<arg choice="plain"><option>--help</option></arg>
101
<arg choice="plain"><option>-?</option></arg>
105
<command>&COMMANDNAME;</command>
106
<arg choice="plain"><option>--usage</option></arg>
109
<command>&COMMANDNAME;</command>
111
<arg choice="plain"><option>--version</option></arg>
112
<arg choice="plain"><option>-V</option></arg>
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>
117
99
<refsect1 id="description">
118
100
<title>DESCRIPTION</title>
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.
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
151
110
<refsect1 id="options">
152
111
<title>OPTIONS</title>
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
113
Commonly not invoked as command lines but from configuration
114
file of plugin runner.
165
<term><option>--connect=<replaceable
166
>ADDRESS</replaceable><literal>:</literal><replaceable
167
>PORT</replaceable></option></term>
169
<replaceable>ADDRESS</replaceable><literal>:</literal
170
><replaceable>PORT</replaceable></option></term>
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.
180
This option is normally only useful for testing and
187
<term><option>--interface=
188
<replaceable>NAME</replaceable></option></term>
190
<replaceable>NAME</replaceable></option></term>
193
Network interface that will be brought up and scanned for
194
Mandos servers to connect to. The default it
195
<quote><literal>eth0</literal></quote>.
198
If the <option>--connect</option> option is used, this
199
specifies the interface to use to connect to the address
206
<term><option>--pubkey=<replaceable
207
>FILE</replaceable></option></term>
209
<replaceable>FILE</replaceable></option></term>
212
OpenPGP public key file name. The default name is
213
<quote><filename>/conf/conf.d/mandos/pubkey.txt</filename
220
<term><option>--seckey=<replaceable
221
>FILE</replaceable></option></term>
223
<replaceable>FILE</replaceable></option></term>
226
OpenPGP secret key file name. The default name is
227
<quote><filename>/conf/conf.d/mandos/seckey.txt</filename
234
<term><option>--priority=<replaceable
235
>STRING</replaceable></option></term>
237
<xi:include href="../mandos-options.xml"
238
xpointer="priority"/>
243
<term><option>--dh-bits=<replaceable
244
>BITS</replaceable></option></term>
247
Sets the number of bits to use for the prime number in the
248
TLS Diffie-Hellman key exchange. Default is 1024.
254
<term><option>--debug</option></term>
257
Enable debug mode. This will enable a lot of output to
258
standard error about what the program is doing. The
259
program will still perform all other functions normally.
262
It will also enable debug mode in the Avahi and GnuTLS
263
libraries, making them print large amounts of debugging
270
<term><option>--help</option></term>
271
<term><option>-?</option></term>
274
Gives a help message about options and their meanings.
280
<term><option>--usage</option></term>
283
Gives a short usage message.
289
<term><option>--version</option></term>
290
<term><option>-V</option></term>
293
Prints the program version.
119
<term><literal>-c</literal>, <literal>--connect=<replaceable>
120
IP</replaceable></literal></term>
123
Connect directly to a sepcified 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
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
323
226
<refsect1 id="exit_status">
324
227
<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.
336
<refsect1 id="environment">
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>
346
232
<refsect1 id="file">
347
233
<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> -->
372
<refsect1 id="example">
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>
238
<refsect1 id="notes">
250
<refsect1 id="examples">
251
<title>EXAMPLES</title>
427
256
<refsect1 id="security">
428
257
<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. The defense against this is
453
that the server is supposed to notice the client disappearing
454
and will stop giving out the encrypted data. Therefore, it is
455
important to set the timeout and checker interval values tightly
456
on the 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
474
262
<refsect1 id="see_also">
475
263
<title>SEE ALSO</title>
477
<citerefentry><refentrytitle>cryptsetup</refentrytitle>
478
<manvolnum>8</manvolnum></citerefentry>,
479
<citerefentry><refentrytitle>crypttab</refentrytitle>
480
<manvolnum>5</manvolnum></citerefentry>,
481
265
<citerefentry><refentrytitle>mandos</refentrytitle>
482
<manvolnum>8</manvolnum></citerefentry>,
483
<citerefentry><refentrytitle>password-prompt</refentrytitle>
484
<manvolnum>8mandos</manvolnum></citerefentry>,
485
<citerefentry><refentrytitle>plugin-runner</refentrytitle>
266
<manvolnum>8</manvolnum></citerefentry>, <citerefentry>
267
<refentrytitle>plugin-runner</refentrytitle>
268
<manvolnum>8mandos</manvolnum></citerefentry> and <citerefentry>
269
<refentrytitle>password-prompt</refentrytitle>
486
270
<manvolnum>8mandos</manvolnum></citerefentry>
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.
606
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607
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608
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609
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