127
151
</refsynopsisdiv>
129
153
<refsect1 id="description">
130
154
<title>DESCRIPTION</title>
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
156
<command>&COMMANDNAME;</command> is a program which is meant to
157
be specified as a <quote>keyscript</quote> for the root disk in
138
158
<citerefentry><refentrytitle>crypttab</refentrytitle>
139
<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.
159
<manvolnum>5</manvolnum></citerefentry>. The aim of this
160
program is therefore to output a password, which then
161
<citerefentry><refentrytitle>cryptsetup</refentrytitle>
162
<manvolnum>8</manvolnum></citerefentry> will use to unlock the
166
This program is not meant to be invoked directly, but can be in
167
order to test it. Note that any password obtained will simply
168
be output on standard output.
172
<refsect1 id="purpose">
173
<title>PURPOSE</title>
175
The purpose of this is to enable <emphasis>remote and unattended
176
rebooting</emphasis> of client host computer with an
177
<emphasis>encrypted root file system</emphasis>. See <xref
178
linkend="overview"/> for details.
149
183
<title>OPTIONS</title>
186
<term><option>--global-env
187
<replaceable>ENV</replaceable><literal>=</literal><replaceable
188
>value</replaceable></option></term>
190
<replaceable>ENV</replaceable><literal>=</literal><replaceable
191
>value</replaceable></option></term>
194
This option will add an environment variable setting to
195
all plugins. This will override any inherited environment
202
<term><option>--env-for
203
<replaceable>PLUGIN</replaceable><literal>:</literal
204
><replaceable>ENV</replaceable><literal>=</literal
205
><replaceable>value</replaceable></option></term>
207
<replaceable>PLUGIN</replaceable><literal>:</literal
208
><replaceable>ENV</replaceable><literal>=</literal
209
><replaceable>value</replaceable></option></term>
212
This option will add an environment variable setting to
213
the <replaceable>PLUGIN</replaceable> plugin. This will
214
override any inherited environment variables or
215
environment variables specified using
216
<option>--global-env</option>.
152
222
<term><option>--global-options
153
223
<replaceable>OPTIONS</replaceable></option></term>
155
225
<replaceable>OPTIONS</replaceable></option></term>
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.
228
Pass some options to <emphasis>all</emphasis> plugins.
229
<replaceable>OPTIONS</replaceable> is a comma separated
230
list of options. This is not a very useful option, except
231
for specifying the <quote><option>--debug</option></quote>
232
option to all plugins.
166
238
<term><option>--options-for
167
239
<replaceable>PLUGIN</replaceable><literal>:</literal
171
243
><replaceable>OPTION</replaceable></option></term>
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.
246
Pass some options to a specific plugin. <replaceable
247
>PLUGIN</replaceable> is the name (file basename) of a
248
plugin, and <replaceable>OPTIONS</replaceable> is a comma
249
separated list of options.
252
Note that since options are not split on whitespace, the
253
way to pass, to the plugin
254
<quote><filename>foo</filename></quote>, the option
255
<option>--bar</option> with the option argument
256
<quote>baz</quote> is either
257
<userinput>--options-for=foo:--bar=baz</userinput> or
258
<userinput>--options-for=foo:--bar,baz</userinput>. Using
259
<userinput>--options-for="foo:--bar baz"</userinput>. will
260
<emphasis>not</emphasis> work.
182
<term><option> --disable
266
<term><option>--disable
183
267
<replaceable>PLUGIN</replaceable></option></term>
185
269
<replaceable>PLUGIN</replaceable></option></term>
188
Disable a specific plugin
272
Disable the plugin named
273
<replaceable>PLUGIN</replaceable>. The plugin will not be
280
<term><option>--enable
281
<replaceable>PLUGIN</replaceable></option></term>
283
<replaceable>PLUGIN</replaceable></option></term>
286
Re-enable the plugin named
287
<replaceable>PLUGIN</replaceable>. This is only useful to
288
undo a previous <option>--disable</option> option, maybe
289
from the configuration file.
194
295
<term><option>--groupid
195
296
<replaceable>ID</replaceable></option></term>
198
Group ID the plugins will run as
299
Change to group ID <replaceable>ID</replaceable> on
300
startup. The default is 65534. All plugins will be
301
started using this group ID. <emphasis>Note:</emphasis>
302
This must be a number, not a name.
204
308
<term><option>--userid
205
309
<replaceable>ID</replaceable></option></term>
208
User ID the plugins will run as
312
Change to user ID <replaceable>ID</replaceable> on
313
startup. The default is 65534. All plugins will be
314
started using this user ID. <emphasis>Note:</emphasis>
315
This must be a number, not a name.
214
321
<term><option>--plugin-dir
215
322
<replaceable>DIRECTORY</replaceable></option></term>
218
Specify a different plugin directory
325
Specify a different plugin directory. The default is
326
<filename>/lib/mandos/plugins.d</filename>, which will
327
exist in the initial <acronym>RAM</acronym> disk
334
<term><option>--plugin-helper-dir
335
<replaceable>DIRECTORY</replaceable></option></term>
338
Specify a different plugin helper directory. The default
339
is <filename>/lib/mandos/plugin-helpers</filename>, which
340
will exist in the initial <acronym>RAM</acronym> disk
341
environment. (This will simply be passed to all plugins
342
via the <envar>MANDOSPLUGINHELPERDIR</envar> environment
343
variable. See <xref linkend="writing_plugins"/>)
349
<term><option>--config-file
350
<replaceable>FILE</replaceable></option></term>
353
Specify a different file to read additional options from.
354
See <xref linkend="files"/>. Other command line options
355
will override options specified in the file.
243
390
<term><option>--usage</option></term>
246
Gives a short usage message
393
Gives a short usage message.
252
399
<term><option>--version</option></term>
253
400
<term><option>-V</option></term>
256
Prints the program version
403
Prints the program version.
410
<refsect1 id="overview">
411
<title>OVERVIEW</title>
412
<xi:include href="overview.xml"/>
414
This program will run on the client side in the initial
415
<acronym>RAM</acronym> disk environment, and is responsible for
416
getting a password. It does this by running plugins, one of
417
which will normally be the actual client program communicating
421
<refsect1 id="plugins">
422
<title>PLUGINS</title>
424
This program will get a password by running a number of
425
<firstterm>plugins</firstterm>, which are simply executable
426
programs in a directory in the initial <acronym>RAM</acronym>
427
disk environment. The default directory is
428
<filename>/lib/mandos/plugins.d</filename>, but this can be
429
changed with the <option>--plugin-dir</option> option. The
430
plugins are started in parallel, and the first plugin to output
431
a password <emphasis>and</emphasis> exit with a successful exit
432
code will make this plugin-runner output the password from that
433
plugin, stop any other plugins, and exit.
436
<refsect2 id="writing_plugins">
437
<title>WRITING PLUGINS</title>
439
A plugin is simply a program which prints a password to its
440
standard output and then exits with a successful (zero) exit
441
status. If the exit status is not zero, any output on
442
standard output will be ignored by the plugin runner. Any
443
output on its standard error channel will simply be passed to
444
the standard error of the plugin runner, usually the system
448
If the password is a single-line, manually entered passprase,
449
a final trailing newline character should
450
<emphasis>not</emphasis> be printed.
453
The plugin will run in the initial RAM disk environment, so
454
care must be taken not to depend on any files or running
455
services not available there. Any helper executables required
456
by the plugin (which are not in the <envar>PATH</envar>) can
457
be placed in the plugin helper directory, the name of which
458
will be made available to the plugin via the
459
<envar>MANDOSPLUGINHELPERDIR</envar> environment variable.
462
The plugin must exit cleanly and free all allocated resources
463
upon getting the TERM signal, since this is what the plugin
464
runner uses to stop all other plugins when one plugin has
465
output a password and exited cleanly.
468
The plugin must not use resources, like for instance reading
469
from the standard input, without knowing that no other plugin
473
It is useful, but not required, for the plugin to take the
474
<option>--debug</option> option.
479
<refsect1 id="fallback">
480
<title>FALLBACK</title>
482
If no plugins succeed, this program will, as a fallback, ask for
483
a password on the console using <citerefentry><refentrytitle
484
>getpass</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
485
and output it. This is not meant to be the normal mode of
486
operation, as there is a separate plugin for getting a password
263
491
<refsect1 id="exit_status">
264
492
<title>EXIT STATUS</title>
494
Exit status of this program is zero if no errors were
495
encountered, and otherwise not. The fallback (see <xref
496
linkend="fallback"/>) may or may not have succeeded in either
501
<refsect1 id="environment">
502
<title>ENVIRONMENT</title>
504
This program does not use any environment variables itself, it
505
only passes on its environment to all the plugins. The
506
environment passed to plugins can be modified using the
507
<option>--global-env</option> and <option>--env-for</option>
508
options. Also, the <option>--plugin-helper-dir</option> option
509
will affect the environment variable
510
<envar>MANDOSPLUGINHELPERDIR</envar> for the plugins.
514
<refsect1 id="files">
270
515
<title>FILES</title>
275
<refsect1 id="notes">
520
>/conf/conf.d/mandos/plugin-runner.conf</filename></term>
523
Since this program will be run as a keyscript, there is
524
little to no opportunity to pass command line arguments
525
to it. Therefore, it will <emphasis>also</emphasis>
526
read this file and use its contents as
527
whitespace-separated command line options. Also,
528
everything from a <quote>#</quote> character to the end
529
of a line is ignored.
532
This program is meant to run in the initial RAM disk
533
environment, so that is where this file is assumed to
534
exist. The file does not need to exist in the normal
538
This file will be processed <emphasis>before</emphasis>
539
the normal command line options, so the latter can
540
override the former, if need be.
543
This file name is the default; the file to read for
544
arguments can be changed using the
545
<option>--config-file</option> option.
550
<term><filename class="directory"
551
>/lib/mandos/plugins.d</filename></term>
554
The default plugin directory; can be changed by the
555
<option>--plugin-dir</option> option.
560
<term><filename class="directory"
561
>/lib/mandos/plugin-helpers</filename></term>
564
The default plugin helper directory; can be changed by
565
the <option>--plugin-helper-dir</option> option.
281
573
<refsect1 id="bugs">
282
574
<title>BUGS</title>
576
The <option>--config-file</option> option is ignored when
577
specified from within a configuration file.
579
<xi:include href="bugs.xml"/>
287
582
<refsect1 id="examples">
288
583
<title>EXAMPLE</title>
586
Normal invocation needs no options:
589
<userinput>&COMMANDNAME;</userinput>
594
Run the program, but not the plugins, in debug mode:
598
<!-- do not wrap this line -->
599
<userinput>&COMMANDNAME; --debug</userinput>
605
Run all plugins, but run the <quote>foo</quote> plugin in
610
<!-- do not wrap this line -->
611
<userinput>&COMMANDNAME; --options-for=foo:--debug</userinput>
617
Run all plugins, but not the program, in debug mode:
621
<!-- do not wrap this line -->
622
<userinput>&COMMANDNAME; --global-options=--debug</userinput>
628
Read a different configuration file, run plugins from a
629
different directory, specify an alternate plugin helper
630
directory and add two options to the
631
<citerefentry><refentrytitle >mandos-client</refentrytitle>
632
<manvolnum>8mandos</manvolnum></citerefentry> plugin:
636
<!-- do not wrap this line -->
637
<userinput>cd /etc/keys/mandos; &COMMANDNAME; --config-file=/etc/mandos/plugin-runner.conf --plugin-dir /usr/lib/x86_64-linux-gnu/mandos/plugins.d --plugin-helper-dir /usr/lib/x86_64-linux-gnu/mandos/plugin-helpers --options-for=mandos-client:--pubkey=pubkey.txt,--seckey=seckey.txt,--tls-pubkey=tls-pubkey.pem,--tls-privkey=tls-privkey.pem</userinput>
293
642
<refsect1 id="security">
294
643
<title>SECURITY</title>
645
This program will, when starting, try to switch to another user.
646
If it is started as root, it will succeed, and will by default
647
switch to user and group 65534, which are assumed to be
648
non-privileged. This user and group is then what all plugins
649
will be started as. Therefore, the only way to run a plugin as
650
a privileged user is to have the set-user-ID or set-group-ID bit
651
set on the plugin executable file (see <citerefentry>
652
<refentrytitle>execve</refentrytitle><manvolnum>2</manvolnum>
656
If this program is used as a keyscript in <citerefentry
657
><refentrytitle>crypttab</refentrytitle><manvolnum>5</manvolnum>
658
</citerefentry>, there is a slight risk that if this program
659
fails to work, there might be no way to boot the system except
660
for booting from another media and editing the initial RAM disk
661
image to not run this program. This is, however, unlikely,
662
since the <citerefentry><refentrytitle
663
>password-prompt</refentrytitle><manvolnum>8mandos</manvolnum>
664
</citerefentry> plugin will read a password from the console in
665
case of failure of the other plugins, and this plugin runner
666
will also, in case of catastrophic failure, itself fall back to
667
asking and outputting a password on the console (see <xref
668
linkend="fallback"/>).
299
672
<refsect1 id="see_also">
300
673
<title>SEE ALSO</title>
675
<citerefentry><refentrytitle>intro</refentrytitle>
676
<manvolnum>8mandos</manvolnum></citerefentry>,
302
677
<citerefentry><refentrytitle>cryptsetup</refentrytitle>
303
678
<manvolnum>8</manvolnum></citerefentry>,
679
<citerefentry><refentrytitle>crypttab</refentrytitle>
680
<manvolnum>5</manvolnum></citerefentry>,
681
<citerefentry><refentrytitle>execve</refentrytitle>
682
<manvolnum>2</manvolnum></citerefentry>,
304
683
<citerefentry><refentrytitle>mandos</refentrytitle>
305
684
<manvolnum>8</manvolnum></citerefentry>,
306
685
<citerefentry><refentrytitle>password-prompt</refentrytitle>
307
686
<manvolnum>8mandos</manvolnum></citerefentry>,
308
<citerefentry><refentrytitle>password-request</refentrytitle>
687
<citerefentry><refentrytitle>mandos-client</refentrytitle>
309
688
<manvolnum>8mandos</manvolnum></citerefentry>
314
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