137
127
</refsynopsisdiv>
139
129
<refsect1 id="description">
140
130
<title>DESCRIPTION</title>
142
<command>&COMMANDNAME;</command> is a program which is meant to
143
be specified as a <quote>keyscript</quote> for the root disk in
132
<command>&COMMANDNAME;</command> is a plugin runner that waits
133
for any of its plugins to return sucessfull with a password, and
134
passes it to cryptsetup as stdout message. This command is not
135
meant to be invoked directly, but is instead meant to be run by
136
cryptsetup by being specified in /etc/crypttab as a keyscript
137
and subsequlently started in the initrd environment. See
144
138
<citerefentry><refentrytitle>crypttab</refentrytitle>
145
<manvolnum>5</manvolnum></citerefentry>. The aim of this
146
program is therefore to output a password, which then
147
<citerefentry><refentrytitle>cryptsetup</refentrytitle>
148
<manvolnum>8</manvolnum></citerefentry> will use to unlock the
152
This program is not meant to be invoked directly, but can be in
153
order to test it. Note that any password obtained will simply
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be output on standard output.
158
<refsect1 id="purpose">
159
<title>PURPOSE</title>
161
The purpose of this is to enable <emphasis>remote and unattended
162
rebooting</emphasis> of client host computer with an
163
<emphasis>encrypted root file system</emphasis>. See <xref
164
linkend="overview"/> for details.
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<manvolnum>5</manvolnum></citerefentry> for more information on
144
plugins is looked for in the plugins directory which by default will be
145
/conf/conf.d/mandos/plugins.d if not changed by option --plugin-dir.
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149
<title>OPTIONS</title>
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<term><option>--global-env
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<replaceable>VAR</replaceable><literal>=</literal><replaceable
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>value</replaceable></option></term>
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<replaceable>VAR</replaceable><literal>=</literal><replaceable
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>value</replaceable></option></term>
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This option will add an environment variable setting to
181
all plugins. This will override any inherited environment
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<term><option>--env-for
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<replaceable>PLUGIN</replaceable><literal>:</literal
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><replaceable>ENV</replaceable><literal>=</literal
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><replaceable>value</replaceable></option></term>
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<replaceable>PLUGIN</replaceable><literal>:</literal
194
><replaceable>ENV</replaceable><literal>=</literal
195
><replaceable>value</replaceable></option></term>
198
This option will add an environment variable setting to
199
the <replaceable>PLUGIN</replaceable> plugin. This will
200
override any inherited environment variables or
201
environment variables specified using
202
<option>--global-env</option>.
208
152
<term><option>--global-options
209
153
<replaceable>OPTIONS</replaceable></option></term>
211
155
<replaceable>OPTIONS</replaceable></option></term>
214
Pass some options to <emphasis>all</emphasis> plugins.
215
<replaceable>OPTIONS</replaceable> is a comma separated
216
list of options. This is not a very useful option, except
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for specifying the <quote><option>--debug</option></quote>
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option to all plugins.
158
Global options given to all plugins as additional start
159
arguments. Options are specified with a -o flag followed
160
by a comma separated string of options.
224
166
<term><option>--options-for
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167
<replaceable>PLUGIN</replaceable><literal>:</literal
229
171
><replaceable>OPTION</replaceable></option></term>
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Pass some options to a specific plugin. <replaceable
233
>PLUGIN</replaceable> is the name (file basename) of a
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plugin, and <replaceable>OPTIONS</replaceable> is a comma
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separated list of options.
238
Note that since options are not split on whitespace, the
239
way to pass, to the plugin
240
<quote><filename>foo</filename></quote>, the option
241
<option>--bar</option> with the option argument
242
<quote>baz</quote> is either
243
<userinput>--options-for=foo:--bar=baz</userinput> or
244
<userinput>--options-for=foo:--bar,baz</userinput>. Using
245
<userinput>--options-for="foo:--bar baz"</userinput>. will
246
<emphasis>not</emphasis> work.
174
Plugin specific options given to the plugin as additional
175
start arguments. Options are specified with a -o flag
176
followed by a comma separated string of options.
252
<term><option>--disable
182
<term><option> --disable
253
183
<replaceable>PLUGIN</replaceable></option></term>
255
185
<replaceable>PLUGIN</replaceable></option></term>
258
Disable the plugin named
259
<replaceable>PLUGIN</replaceable>. The plugin will not be
188
Disable a specific plugin
266
<term><option>--enable
267
<replaceable>PLUGIN</replaceable></option></term>
269
<replaceable>PLUGIN</replaceable></option></term>
272
Re-enable the plugin named
273
<replaceable>PLUGIN</replaceable>. This is only useful to
274
undo a previous <option>--disable</option> option, maybe
275
from the configuration file.
281
194
<term><option>--groupid
282
195
<replaceable>ID</replaceable></option></term>
285
Change to group ID <replaceable>ID</replaceable> on
286
startup. The default is 65534. All plugins will be
287
started using this group ID. <emphasis>Note:</emphasis>
288
This must be a number, not a name.
198
Group ID the plugins will run as
371
253
<term><option>-V</option></term>
374
Prints the program version.
256
Prints the program version
381
<refsect1 id="overview">
382
<title>OVERVIEW</title>
383
<xi:include href="overview.xml"/>
385
This program will run on the client side in the initial
386
<acronym>RAM</acronym> disk environment, and is responsible for
387
getting a password. It does this by running plugins, one of
388
which will normally be the actual client program communicating
392
<refsect1 id="plugins">
393
<title>PLUGINS</title>
395
This program will get a password by running a number of
396
<firstterm>plugins</firstterm>, which are simply executable
397
programs in a directory in the initial <acronym>RAM</acronym>
398
disk environment. The default directory is
399
<filename>/lib/mandos/plugins.d</filename>, but this can be
400
changed with the <option>--plugin-dir</option> option. The
401
plugins are started in parallel, and the first plugin to output
402
a password <emphasis>and</emphasis> exit with a successful exit
403
code will make this plugin-runner output the password from that
404
plugin, stop any other plugins, and exit.
407
<refsect2 id="writing_plugins">
408
<title>WRITING PLUGINS</title>
410
A plugin is simply a program which prints a password to its
411
standard output and then exits with a successful (zero) exit
412
status. If the exit status is not zero, any output on
413
standard output will be ignored by the plugin runner. Any
414
output on its standard error channel will simply be passed to
415
the standard error of the plugin runner, usually the system
419
The plugin will run in the initial RAM disk environment, so
420
care must be taken not to depend on any files or running
421
services not available there.
424
The plugin must exit cleanly and free all allocated resources
425
upon getting the TERM signal, since this is what the plugin
426
runner uses to stop all other plugins when one plugin has
427
output a password and exited cleanly.
430
The plugin must not use resources, like for instance reading
431
from the standard input, without knowing that no other plugin
435
It is useful, but not required, for the plugin to take the
436
<option>--debug</option> option.
441
<refsect1 id="fallback">
442
<title>FALLBACK</title>
444
If no plugins succeed, this program will, as a fallback, ask for
445
a password on the console using <citerefentry><refentrytitle
446
>getpass</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
447
and output it. This is not meant to be the normal mode of
448
operation, as there is a separate plugin for getting a password
453
263
<refsect1 id="exit_status">
454
264
<title>EXIT STATUS</title>
456
Exit status of this program is zero if no errors were
457
encountered, and otherwise not. The fallback (see <xref
458
linkend="fallback"/>) may or may not have succeeded in either
463
<refsect1 id="environment">
464
<title>ENVIRONMENT</title>
466
This program does not use any environment variables itself, it
467
only passes on its environment to all the plugins. The
468
environment passed to plugins can be modified using the
469
<option>--global-env</option> and <option>--env-for</option>
474
<refsect1 id="files">
475
270
<title>FILES</title>
480
>/conf/conf.d/mandos/plugin-runner.conf</filename></term>
483
Since this program will be run as a keyscript, there is
484
little to no opportunity to pass command line arguments
485
to it. Therefore, it will <emphasis>also</emphasis>
486
read this file and use its contents as
487
whitespace-separated command line options. Also,
488
everything from a <quote>#</quote> character to the end
489
of a line is ignored.
492
This program is meant to run in the initial RAM disk
493
environment, so that is where this file is assumed to
494
exist. The file does not need to exist in the normal
498
This file will be processed <emphasis>before</emphasis>
499
the normal command line options, so the latter can
500
override the former, if need be.
503
This file name is the default; the file to read for
504
arguments can be changed using the
505
<option>--config-file</option> option.
275
<refsect1 id="notes">
513
281
<refsect1 id="bugs">
514
282
<title>BUGS</title>
516
The <option>--config-file</option> option is ignored when
517
specified from within a configuration file.
521
287
<refsect1 id="examples">
522
288
<title>EXAMPLE</title>
525
Normal invocation needs no options:
528
<userinput>&COMMANDNAME;</userinput>
533
Run the program, but not the plugins, in debug mode:
537
<!-- do not wrap this line -->
538
<userinput>&COMMANDNAME; --debug</userinput>
544
Run all plugins, but run the <quote>foo</quote> plugin in
549
<!-- do not wrap this line -->
550
<userinput>&COMMANDNAME; --options-for=foo:--debug</userinput>
556
Run all plugins, but not the program, in debug mode:
560
<!-- do not wrap this line -->
561
<userinput>&COMMANDNAME; --global-options=--debug</userinput>
567
Run plugins from a different directory and add two
568
options to the <citerefentry><refentrytitle
569
>password-request</refentrytitle>
570
<manvolnum>8mandos</manvolnum></citerefentry> plugin:
574
<!-- do not wrap this line -->
575
<userinput>&COMMANDNAME; --plugin-dir=plugins.d --options-for=password-request:--pubkey=keydir/pubkey.txt,--seckey=keydir/seckey.txt</userinput>
580
293
<refsect1 id="security">
581
294
<title>SECURITY</title>
583
This program will, when starting, try to switch to another user.
584
If it is started as root, it will succeed, and will by default
585
switch to user and group 65534, which are assumed to be
586
non-privileged. This user and group is then what all plugins
587
will be started as. Therefore, the only way to run a plugin as
588
a privileged user is to have the set-user-ID or set-group-ID bit
589
set on the plugin executable files (see <citerefentry>
590
<refentrytitle>execve</refentrytitle><manvolnum>2</manvolnum>
594
If this program is used as a keyscript in <citerefentry
595
><refentrytitle>crypttab</refentrytitle><manvolnum>5</manvolnum>
596
</citerefentry>, there is a slight risk that if this program
597
fails to work, there might be no way to boot the system except
598
for booting from another media and editing the initial RAM disk
599
image to not run this program. This is, however, unlikely,
600
since the <citerefentry><refentrytitle
601
>password-prompt</refentrytitle><manvolnum>8mandos</manvolnum>
602
</citerefentry> plugin will read a password from the console in
603
case of failure of the other plugins, and this plugin runner
604
will also, in case of catastrophic failure, itself fall back to
605
asking and outputting a password on the console (see <xref
606
linkend="fallback"/>).
610
299
<refsect1 id="see_also">
611
300
<title>SEE ALSO</title>
613
302
<citerefentry><refentrytitle>cryptsetup</refentrytitle>
614
303
<manvolnum>8</manvolnum></citerefentry>,
615
<citerefentry><refentrytitle>crypttab</refentrytitle>
616
<manvolnum>5</manvolnum></citerefentry>,
617
<citerefentry><refentrytitle>execve</refentrytitle>
618
<manvolnum>2</manvolnum></citerefentry>,
619
304
<citerefentry><refentrytitle>mandos</refentrytitle>
620
305
<manvolnum>8</manvolnum></citerefentry>,
621
306
<citerefentry><refentrytitle>password-prompt</refentrytitle>