139
149
</refsynopsisdiv>
141
151
<refsect1 id="description">
142
152
<title>DESCRIPTION</title>
144
<command>&COMMANDNAME;</command> is a program which is meant to
145
be specified as a <quote>keyscript</quote> for the root disk in
154
<command>&COMMANDNAME;</command> is a plugin runner that waits
155
for any of its plugins to return sucessfull with a password, and
156
passes it to cryptsetup as stdout message. This command is not
157
meant to be invoked directly, but is instead meant to be run by
158
cryptsetup by being specified in /etc/crypttab as a keyscript
159
and subsequlently started in the initrd environment. See
146
160
<citerefentry><refentrytitle>crypttab</refentrytitle>
147
<manvolnum>5</manvolnum></citerefentry>. The aim of this
148
program is therefore to output a password, which then
149
<citerefentry><refentrytitle>cryptsetup</refentrytitle>
150
<manvolnum>8</manvolnum></citerefentry> will use to unlock the
154
This program is not meant to be invoked directly, but can be in
155
order to test it. Note that any password obtained will simply
156
be output on standard output.
160
<refsect1 id="purpose">
161
<title>PURPOSE</title>
163
The purpose of this is to enable <emphasis>remote and unattended
164
rebooting</emphasis> of client host computer with an
165
<emphasis>encrypted root file system</emphasis>. See <xref
166
linkend="overview"/> for details.
161
<manvolnum>5</manvolnum></citerefentry> for more information on
166
plugins is looked for in the plugins directory which by default will be
167
/conf/conf.d/mandos/plugins.d if not changed by option --plugin-dir.
171
171
<title>OPTIONS</title>
174
<term><option>--global-env
175
<replaceable>ENV</replaceable><literal>=</literal><replaceable
176
>value</replaceable></option></term>
178
<replaceable>ENV</replaceable><literal>=</literal><replaceable
179
>value</replaceable></option></term>
182
This option will add an environment variable setting to
183
all plugins. This will override any inherited environment
190
<term><option>--env-for
191
<replaceable>PLUGIN</replaceable><literal>:</literal
192
><replaceable>ENV</replaceable><literal>=</literal
193
><replaceable>value</replaceable></option></term>
195
<replaceable>PLUGIN</replaceable><literal>:</literal
196
><replaceable>ENV</replaceable><literal>=</literal
197
><replaceable>value</replaceable></option></term>
200
This option will add an environment variable setting to
201
the <replaceable>PLUGIN</replaceable> plugin. This will
202
override any inherited environment variables or
203
environment variables specified using
204
<option>--global-env</option>.
210
174
<term><option>--global-options
211
175
<replaceable>OPTIONS</replaceable></option></term>
213
177
<replaceable>OPTIONS</replaceable></option></term>
216
Pass some options to <emphasis>all</emphasis> plugins.
217
<replaceable>OPTIONS</replaceable> is a comma separated
218
list of options. This is not a very useful option, except
219
for specifying the <quote><option>--debug</option></quote>
220
option to all plugins.
180
Global options given to all plugins as additional start
181
arguments. Options are specified with a -o flag followed
182
by a comma separated string of options.
226
188
<term><option>--options-for
227
189
<replaceable>PLUGIN</replaceable><literal>:</literal
231
193
><replaceable>OPTION</replaceable></option></term>
234
Pass some options to a specific plugin. <replaceable
235
>PLUGIN</replaceable> is the name (file basename) of a
236
plugin, and <replaceable>OPTIONS</replaceable> is a comma
237
separated list of options.
240
Note that since options are not split on whitespace, the
241
way to pass, to the plugin
242
<quote><filename>foo</filename></quote>, the option
243
<option>--bar</option> with the option argument
244
<quote>baz</quote> is either
245
<userinput>--options-for=foo:--bar=baz</userinput> or
246
<userinput>--options-for=foo:--bar,baz</userinput>. Using
247
<userinput>--options-for="foo:--bar baz"</userinput>. will
248
<emphasis>not</emphasis> work.
196
Plugin specific options given to the plugin as additional
197
start arguments. Options are specified with a -o flag
198
followed by a comma separated string of options.
254
<term><option>--disable
204
<term><option> --disable
255
205
<replaceable>PLUGIN</replaceable></option></term>
257
207
<replaceable>PLUGIN</replaceable></option></term>
260
Disable the plugin named
261
<replaceable>PLUGIN</replaceable>. The plugin will not be
210
Disable a specific plugin
268
<term><option>--enable
269
<replaceable>PLUGIN</replaceable></option></term>
271
<replaceable>PLUGIN</replaceable></option></term>
274
Re-enable the plugin named
275
<replaceable>PLUGIN</replaceable>. This is only useful to
276
undo a previous <option>--disable</option> option, maybe
277
from the configuration file.
283
216
<term><option>--groupid
284
217
<replaceable>ID</replaceable></option></term>
287
Change to group ID <replaceable>ID</replaceable> on
288
startup. The default is 65534. All plugins will be
289
started using this group ID. <emphasis>Note:</emphasis>
290
This must be a number, not a name.
220
Group ID the plugins will run as
296
226
<term><option>--userid
297
227
<replaceable>ID</replaceable></option></term>
300
Change to user ID <replaceable>ID</replaceable> on
301
startup. The default is 65534. All plugins will be
302
started using this user ID. <emphasis>Note:</emphasis>
303
This must be a number, not a name.
230
User ID the plugins will run as
309
236
<term><option>--plugin-dir
310
237
<replaceable>DIRECTORY</replaceable></option></term>
313
Specify a different plugin directory. The default is
314
<filename>/lib/mandos/plugins.d</filename>, which will
315
exist in the initial <acronym>RAM</acronym> disk
322
<term><option>--config-file
323
<replaceable>FILE</replaceable></option></term>
326
Specify a different file to read additional options from.
327
See <xref linkend="files"/>. Other command line options
328
will override options specified in the file.
240
Specify a different plugin directory
363
265
<term><option>--usage</option></term>
366
Gives a short usage message.
268
Gives a short usage message
372
274
<term><option>--version</option></term>
373
275
<term><option>-V</option></term>
376
Prints the program version.
278
Prints the program version
383
<refsect1 id="overview">
384
<title>OVERVIEW</title>
385
<xi:include href="overview.xml"/>
387
This program will run on the client side in the initial
388
<acronym>RAM</acronym> disk environment, and is responsible for
389
getting a password. It does this by running plugins, one of
390
which will normally be the actual client program communicating
394
<refsect1 id="plugins">
395
<title>PLUGINS</title>
397
This program will get a password by running a number of
398
<firstterm>plugins</firstterm>, which are simply executable
399
programs in a directory in the initial <acronym>RAM</acronym>
400
disk environment. The default directory is
401
<filename>/lib/mandos/plugins.d</filename>, but this can be
402
changed with the <option>--plugin-dir</option> option. The
403
plugins are started in parallel, and the first plugin to output
404
a password <emphasis>and</emphasis> exit with a successful exit
405
code will make this plugin-runner output the password from that
406
plugin, stop any other plugins, and exit.
409
<refsect2 id="writing_plugins">
410
<title>WRITING PLUGINS</title>
412
A plugin is simply a program which prints a password to its
413
standard output and then exits with a successful (zero) exit
414
status. If the exit status is not zero, any output on
415
standard output will be ignored by the plugin runner. Any
416
output on its standard error channel will simply be passed to
417
the standard error of the plugin runner, usually the system
421
If the password is a single-line, manually entered passprase,
422
a final trailing newline character should
423
<emphasis>not</emphasis> be printed.
426
The plugin will run in the initial RAM disk environment, so
427
care must be taken not to depend on any files or running
428
services not available there.
431
The plugin must exit cleanly and free all allocated resources
432
upon getting the TERM signal, since this is what the plugin
433
runner uses to stop all other plugins when one plugin has
434
output a password and exited cleanly.
437
The plugin must not use resources, like for instance reading
438
from the standard input, without knowing that no other plugin
442
It is useful, but not required, for the plugin to take the
443
<option>--debug</option> option.
448
<refsect1 id="fallback">
449
<title>FALLBACK</title>
451
If no plugins succeed, this program will, as a fallback, ask for
452
a password on the console using <citerefentry><refentrytitle
453
>getpass</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
454
and output it. This is not meant to be the normal mode of
455
operation, as there is a separate plugin for getting a password
460
285
<refsect1 id="exit_status">
461
286
<title>EXIT STATUS</title>
463
Exit status of this program is zero if no errors were
464
encountered, and otherwise not. The fallback (see <xref
465
linkend="fallback"/>) may or may not have succeeded in either
470
<refsect1 id="environment">
471
<title>ENVIRONMENT</title>
473
This program does not use any environment variables itself, it
474
only passes on its environment to all the plugins. The
475
environment passed to plugins can be modified using the
476
<option>--global-env</option> and <option>--env-for</option>
481
<refsect1 id="files">
482
292
<title>FILES</title>
487
>/conf/conf.d/mandos/plugin-runner.conf</filename></term>
490
Since this program will be run as a keyscript, there is
491
little to no opportunity to pass command line arguments
492
to it. Therefore, it will <emphasis>also</emphasis>
493
read this file and use its contents as
494
whitespace-separated command line options. Also,
495
everything from a <quote>#</quote> character to the end
496
of a line is ignored.
499
This program is meant to run in the initial RAM disk
500
environment, so that is where this file is assumed to
501
exist. The file does not need to exist in the normal
505
This file will be processed <emphasis>before</emphasis>
506
the normal command line options, so the latter can
507
override the former, if need be.
510
This file name is the default; the file to read for
511
arguments can be changed using the
512
<option>--config-file</option> option.
297
<refsect1 id="notes">
520
303
<refsect1 id="bugs">
521
304
<title>BUGS</title>
523
The <option>--config-file</option> option is ignored when
524
specified from within a configuration file.
528
309
<refsect1 id="examples">
529
310
<title>EXAMPLE</title>
532
Normal invocation needs no options:
535
<userinput>&COMMANDNAME;</userinput>
540
Run the program, but not the plugins, in debug mode:
544
<!-- do not wrap this line -->
545
<userinput>&COMMANDNAME; --debug</userinput>
551
Run all plugins, but run the <quote>foo</quote> plugin in
556
<!-- do not wrap this line -->
557
<userinput>&COMMANDNAME; --options-for=foo:--debug</userinput>
563
Run all plugins, but not the program, in debug mode:
567
<!-- do not wrap this line -->
568
<userinput>&COMMANDNAME; --global-options=--debug</userinput>
574
Run plugins from a different directory, read a different
575
configuration file, and add two options to the
576
<citerefentry><refentrytitle >mandos-client</refentrytitle>
577
<manvolnum>8mandos</manvolnum></citerefentry> plugin:
581
<!-- do not wrap this line -->
582
<userinput>&COMMANDNAME; --config-file=/etc/mandos/plugin-runner.conf --plugin-dir /usr/lib/mandos/plugins.d --options-for=mandos-client:--pubkey=/etc/keys/mandos/pubkey.txt,--seckey=/etc/keys/mandos/seckey.txt</userinput>
587
315
<refsect1 id="security">
588
316
<title>SECURITY</title>
590
This program will, when starting, try to switch to another user.
591
If it is started as root, it will succeed, and will by default
592
switch to user and group 65534, which are assumed to be
593
non-privileged. This user and group is then what all plugins
594
will be started as. Therefore, the only way to run a plugin as
595
a privileged user is to have the set-user-ID or set-group-ID bit
596
set on the plugin executable file (see <citerefentry>
597
<refentrytitle>execve</refentrytitle><manvolnum>2</manvolnum>
601
If this program is used as a keyscript in <citerefentry
602
><refentrytitle>crypttab</refentrytitle><manvolnum>5</manvolnum>
603
</citerefentry>, there is a slight risk that if this program
604
fails to work, there might be no way to boot the system except
605
for booting from another media and editing the initial RAM disk
606
image to not run this program. This is, however, unlikely,
607
since the <citerefentry><refentrytitle
608
>password-prompt</refentrytitle><manvolnum>8mandos</manvolnum>
609
</citerefentry> plugin will read a password from the console in
610
case of failure of the other plugins, and this plugin runner
611
will also, in case of catastrophic failure, itself fall back to
612
asking and outputting a password on the console (see <xref
613
linkend="fallback"/>).
617
321
<refsect1 id="see_also">
618
322
<title>SEE ALSO</title>
620
324
<citerefentry><refentrytitle>cryptsetup</refentrytitle>
621
325
<manvolnum>8</manvolnum></citerefentry>,
622
<citerefentry><refentrytitle>crypttab</refentrytitle>
623
<manvolnum>5</manvolnum></citerefentry>,
624
<citerefentry><refentrytitle>execve</refentrytitle>
625
<manvolnum>2</manvolnum></citerefentry>,
626
326
<citerefentry><refentrytitle>mandos</refentrytitle>
627
327
<manvolnum>8</manvolnum></citerefentry>,
628
328
<citerefentry><refentrytitle>password-prompt</refentrytitle>
629
329
<manvolnum>8mandos</manvolnum></citerefentry>,
630
<citerefentry><refentrytitle>mandos-client</refentrytitle>
330
<citerefentry><refentrytitle>password-request</refentrytitle>
631
331
<manvolnum>8mandos</manvolnum></citerefentry>
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