1
1
<?xml version="1.0" encoding="UTF-8"?>
2
2
<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN"
3
3
"http://www.oasis-open.org/docbook/xml/4.5/docbookx.dtd" [
4
<!ENTITY COMMANDNAME "mandos-client">
5
<!ENTITY TIMESTAMP "2009-01-24">
6
<!ENTITY % common SYSTEM "../common.ent">
4
<!ENTITY VERSION "1.0">
5
<!ENTITY COMMANDNAME "password-request">
6
<!ENTITY TIMESTAMP "2008-09-03">
10
9
<refentry xmlns:xi="http://www.w3.org/2001/XInclude">
12
11
<title>Mandos Manual</title>
13
<!-- NWalsh’s docbook scripts use this to generate the footer: -->
12
<!-- Nwalsh’s docbook scripts use this to generate the footer: -->
14
13
<productname>Mandos</productname>
15
<productnumber>&version;</productnumber>
14
<productnumber>&VERSION;</productnumber>
16
15
<date>&TIMESTAMP;</date>
48
46
<refname><command>&COMMANDNAME;</command></refname>
50
Client for <application>Mandos</application>
56
54
<command>&COMMANDNAME;</command>
58
56
<arg choice="plain"><option>--connect
59
<replaceable>ADDRESS</replaceable><literal>:</literal
57
<replaceable>IPADDR</replaceable><literal>:</literal
60
58
><replaceable>PORT</replaceable></option></arg>
61
59
<arg choice="plain"><option>-c
62
<replaceable>ADDRESS</replaceable><literal>:</literal
60
<replaceable>IPADDR</replaceable><literal>:</literal
63
61
><replaceable>PORT</replaceable></option></arg>
65
<arg choice="plain"><option>--keydir
66
<replaceable>DIRECTORY</replaceable></option></arg>
67
<arg choice="plain"><option>-d
68
<replaceable>DIRECTORY</replaceable></option></arg>
67
72
<arg choice="plain"><option>--interface
68
73
<replaceable>NAME</replaceable></option></arg>
69
74
<arg choice="plain"><option>-i
117
122
</refsynopsisdiv>
119
124
<refsect1 id="description">
120
125
<title>DESCRIPTION</title>
122
127
<command>&COMMANDNAME;</command> is a client program that
123
128
communicates with <citerefentry><refentrytitle
124
129
>mandos</refentrytitle><manvolnum>8</manvolnum></citerefentry>
125
to get a password. In slightly more detail, this client program
126
brings up a network interface, uses the interface’s IPv6
127
link-local address to get network connectivity, uses Zeroconf to
128
find servers on the local network, and communicates with servers
129
using TLS with an OpenPGP key to ensure authenticity and
130
confidentiality. This client program keeps running, trying all
131
servers on the network, until it receives a satisfactory reply
132
or a TERM signal is received. If no servers are found, or after
133
all servers have been tried, it waits indefinitely for new
130
to get a password. It uses IPv6 link-local addresses to get
131
network connectivity, Zeroconf to find servers, and TLS with an
132
OpenPGP key to ensure authenticity and confidentiality. It
133
keeps running, trying all servers on the network, until it
134
receives a satisfactory reply or a TERM signal is recieved.
137
137
This program is not meant to be run directly; it is really meant
194
<term><option>--keydir=<replaceable
195
>DIRECTORY</replaceable></option></term>
197
<replaceable>DIRECTORY</replaceable></option></term>
200
Directory to read the OpenPGP key files
201
<filename>pubkey.txt</filename> and
202
<filename>seckey.txt</filename> from. The default is
203
<filename>/conf/conf.d/mandos</filename> (in the initial
204
<acronym>RAM</acronym> disk environment).
194
210
<term><option>--interface=
195
211
<replaceable>NAME</replaceable></option></term>
206
222
specifies the interface to use to connect to the address
210
Note that since this program will normally run in the
211
initial RAM disk environment, the interface must be an
212
interface which exists at that stage. Thus, the interface
213
can not be a pseudo-interface such as <quote>br0</quote>
214
or <quote>tun0</quote>; such interfaces will not exist
215
until much later in the boot process, and can not be used
225
232
<replaceable>FILE</replaceable></option></term>
228
OpenPGP public key file name. The default name is
229
<quote><filename>/conf/conf.d/mandos/pubkey.txt</filename
235
OpenPGP public key file base name. This will be combined
236
with the directory from the <option>--keydir</option>
237
option to form an absolute file name. The default name is
238
<quote><literal>pubkey.txt</literal></quote>.
236
244
<term><option>--seckey=<replaceable
237
245
>FILE</replaceable></option></term>
239
247
<replaceable>FILE</replaceable></option></term>
242
OpenPGP secret key file name. The default name is
243
<quote><filename>/conf/conf.d/mandos/seckey.txt</filename
250
OpenPGP secret key file base name. This will be combined
251
with the directory from the <option>--keydir</option>
252
option to form an absolute file name. The default name is
253
<quote><literal>seckey.txt</literal></quote>.
327
336
<filename>/etc/crypttab</filename>, but it would then be
328
337
impossible to enter a password for the encrypted root disk at
329
338
the console, since this program does not read from the console
330
at all. This is why a separate plugin runner (<citerefentry>
331
<refentrytitle>plugin-runner</refentrytitle>
332
<manvolnum>8mandos</manvolnum></citerefentry>) is used to run
333
both this program and others in in parallel,
334
<emphasis>one</emphasis> of which will prompt for passwords on
339
at all. This is why a separate plugin does that, which will be
340
run in parallell to this one by the plugin runner.
414
418
</informalexample>
415
419
<informalexample>
417
Run in debug mode, and use a custom key:
421
Run in debug mode, and use a custom key directory:
421
<!-- do not wrap this line -->
422
<userinput>&COMMANDNAME; --debug --pubkey keydir/pubkey.txt --seckey keydir/seckey.txt</userinput>
424
<!-- do not wrap this line -->
425
<userinput>&COMMANDNAME; --debug --keydir keydir</userinput>
425
427
</informalexample>
426
428
<informalexample>
428
Run in debug mode, with a custom key, and do not use Zeroconf
429
to locate a server; connect directly to the IPv6 address
430
<quote><systemitem class="ipaddress"
430
Run in debug mode, with a custom key directory, and do not use
431
Zeroconf to locate a server; connect directly to the IPv6
432
address <quote><systemitem class="ipaddress"
431
433
>2001:db8:f983:bd0b:30de:ae4a:71f2:f672</systemitem></quote>,
432
434
port 4711, using interface eth2:
436
438
<!-- do not wrap this line -->
437
<userinput>&COMMANDNAME; --debug --pubkey keydir/pubkey.txt --seckey keydir/seckey.txt --connect 2001:db8:f983:bd0b:30de:ae4a:71f2:f672:4711 --interface eth2</userinput>
439
<userinput>&COMMANDNAME; --debug --keydir keydir --connect 2001:db8:f983:bd0b:30de:ae4a:71f2:f672:4711 --interface eth2</userinput>
440
442
</informalexample>
443
445
<refsect1 id="security">
444
446
<title>SECURITY</title>
446
448
This program is set-uid to root, but will switch back to the
447
original (and presumably non-privileged) user and group after
448
bringing up the network interface.
449
original user and group after bringing up the network interface.
451
452
To use this program for its intended purpose (see <xref
465
466
The only remaining weak point is that someone with physical
466
467
access to the client hard drive might turn off the client
467
468
computer, read the OpenPGP keys directly from the hard drive,
468
and communicate with the server. To safeguard against this, the
469
server is supposed to notice the client disappearing and stop
470
giving out the encrypted data. Therefore, it is important to
471
set the timeout and checker interval values tightly on the
472
server. See <citerefentry><refentrytitle
469
and communicate with the server. The defense against this is
470
that the server is supposed to notice the client disappearing
471
and will stop giving out the encrypted data. Therefore, it is
472
important to set the timeout and checker interval values tightly
473
on the server. See <citerefentry><refentrytitle
473
474
>mandos</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
476
It will also help if the checker program on the server is
477
configured to request something from the client which can not be
478
spoofed by someone else on the network, unlike unencrypted
479
<acronym>ICMP</acronym> echo (<quote>ping</quote>) replies.
482
<emphasis>Note</emphasis>: This makes it completely insecure to
483
have <application >Mandos</application> clients which dual-boot
484
to another operating system which is <emphasis>not</emphasis>
485
trusted to keep the initial <acronym>RAM</acronym> disk image
477
<emphasis>Note</emphasis>: This makes it impossible to have
478
<application >Mandos</application> clients which dual-boot to
479
another operating system which does <emphasis>not</emphasis> run
480
a <application>Mandos</application> client.
490
484
<refsect1 id="see_also">
491
485
<title>SEE ALSO</title>
493
<citerefentry><refentrytitle>cryptsetup</refentrytitle>
494
<manvolnum>8</manvolnum></citerefentry>,
495
<citerefentry><refentrytitle>crypttab</refentrytitle>
496
<manvolnum>5</manvolnum></citerefentry>,
497
487
<citerefentry><refentrytitle>mandos</refentrytitle>
498
488
<manvolnum>8</manvolnum></citerefentry>,
499
489
<citerefentry><refentrytitle>password-prompt</refentrytitle>
501
491
<citerefentry><refentrytitle>plugin-runner</refentrytitle>
502
492
<manvolnum>8mandos</manvolnum></citerefentry>
507
<ulink url="http://www.zeroconf.org/">Zeroconf</ulink>
511
Zeroconf is the network protocol standard used for finding
512
Mandos servers on the local network.
518
<ulink url="http://www.avahi.org/">Avahi</ulink>
522
Avahi is the library this program calls to find Zeroconf
529
<ulink url="http://www.gnu.org/software/gnutls/"
534
GnuTLS is the library this client uses to implement TLS for
535
communicating securely with the server, and at the same time
536
send the public OpenPGP key to the server.
542
<ulink url="http://www.gnupg.org/related_software/gpgme/"
547
GPGME is the library used to decrypt the OpenPGP data sent
554
RFC 4291: <citetitle>IP Version 6 Addressing
555
Architecture</citetitle>
560
<term>Section 2.2: <citetitle>Text Representation of
561
Addresses</citetitle></term>
562
<listitem><para/></listitem>
565
<term>Section 2.5.5.2: <citetitle>IPv4-Mapped IPv6
566
Address</citetitle></term>
567
<listitem><para/></listitem>
570
<term>Section 2.5.6, <citetitle>Link-Local IPv6 Unicast
571
Addresses</citetitle></term>
574
This client uses IPv6 link-local addresses, which are
575
immediately usable since a link-local addresses is
576
automatically assigned to a network interfaces when it
586
RFC 4346: <citetitle>The Transport Layer Security (TLS)
587
Protocol Version 1.1</citetitle>
591
TLS 1.1 is the protocol implemented by GnuTLS.
597
RFC 4880: <citetitle>OpenPGP Message Format</citetitle>
601
The data received from the server is binary encrypted
608
RFC 5081: <citetitle>Using OpenPGP Keys for Transport Layer
613
This is implemented by GnuTLS and used by this program so
614
that OpenPGP keys can be used.
496
<ulink url="http://www.zeroconf.org/">Zeroconf</ulink>
500
<ulink url="http://www.avahi.org/">Avahi</ulink>
505
url="http://www.gnu.org/software/gnutls/">GnuTLS</ulink>
510
url="http://www.gnupg.org/related_software/gpgme/"
515
<citation>RFC 4880: <citetitle>OpenPGP Message
516
Format</citetitle></citation>
520
<citation>RFC 5081: <citetitle>Using OpenPGP Keys for
521
Transport Layer Security</citetitle></citation>
525
<citation>RFC 4291: <citetitle>IP Version 6 Addressing
526
Architecture</citetitle>, section 2.5.6, Link-Local IPv6
527
Unicast Addresses</citation>
622
533
<!-- Local Variables: -->
623
534
<!-- time-stamp-start: "<!ENTITY TIMESTAMP [\"']" -->
624
535
<!-- time-stamp-end: "[\"']>" -->