138
127
</refsynopsisdiv>
140
129
<refsect1 id="description">
141
130
<title>DESCRIPTION</title>
143
<command>&COMMANDNAME;</command> is a program which is meant to
144
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
145
138
<citerefentry><refentrytitle>crypttab</refentrytitle>
146
<manvolnum>5</manvolnum></citerefentry>. The aim of this
147
program is therefore to output a password, which then
148
<citerefentry><refentrytitle>cryptsetup</refentrytitle>
149
<manvolnum>8</manvolnum></citerefentry> will use to unlock the
153
This program is not meant to be invoked directly, but can be in
154
order to test it. Note that any password obtained will simply
155
be output on standard output.
159
<refsect1 id="purpose">
160
<title>PURPOSE</title>
162
The purpose of this is to enable <emphasis>remote and unattended
163
rebooting</emphasis> of client host computer with an
164
<emphasis>encrypted root file system</emphasis>. See <xref
165
linkend="overview"/> for details.
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.
170
149
<title>OPTIONS</title>
173
<term><option>--global-env
174
<replaceable>ENV</replaceable><literal>=</literal><replaceable
175
>value</replaceable></option></term>
177
<replaceable>ENV</replaceable><literal>=</literal><replaceable
178
>value</replaceable></option></term>
181
This option will add an environment variable setting to
182
all plugins. This will override any inherited environment
189
<term><option>--env-for
190
<replaceable>PLUGIN</replaceable><literal>:</literal
191
><replaceable>ENV</replaceable><literal>=</literal
192
><replaceable>value</replaceable></option></term>
194
<replaceable>PLUGIN</replaceable><literal>:</literal
195
><replaceable>ENV</replaceable><literal>=</literal
196
><replaceable>value</replaceable></option></term>
199
This option will add an environment variable setting to
200
the <replaceable>PLUGIN</replaceable> plugin. This will
201
override any inherited environment variables or
202
environment variables specified using
203
<option>--global-env</option>.
209
152
<term><option>--global-options
210
153
<replaceable>OPTIONS</replaceable></option></term>
212
155
<replaceable>OPTIONS</replaceable></option></term>
215
Pass some options to <emphasis>all</emphasis> plugins.
216
<replaceable>OPTIONS</replaceable> is a comma separated
217
list of options. This is not a very useful option, except
218
for specifying the <quote><option>--debug</option></quote>
219
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.
225
166
<term><option>--options-for
226
167
<replaceable>PLUGIN</replaceable><literal>:</literal
230
171
><replaceable>OPTION</replaceable></option></term>
233
Pass some options to a specific plugin. <replaceable
234
>PLUGIN</replaceable> is the name (file basename) of a
235
plugin, and <replaceable>OPTIONS</replaceable> is a comma
236
separated list of options.
239
Note that since options are not split on whitespace, the
240
way to pass, to the plugin
241
<quote><filename>foo</filename></quote>, the option
242
<option>--bar</option> with the option argument
243
<quote>baz</quote> is either
244
<userinput>--options-for=foo:--bar=baz</userinput> or
245
<userinput>--options-for=foo:--bar,baz</userinput>. Using
246
<userinput>--options-for="foo:--bar baz"</userinput>. will
247
<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.
253
<term><option>--disable
182
<term><option> --disable
254
183
<replaceable>PLUGIN</replaceable></option></term>
256
185
<replaceable>PLUGIN</replaceable></option></term>
259
Disable the plugin named
260
<replaceable>PLUGIN</replaceable>. The plugin will not be
188
Disable a specific plugin
267
<term><option>--enable
268
<replaceable>PLUGIN</replaceable></option></term>
270
<replaceable>PLUGIN</replaceable></option></term>
273
Re-enable the plugin named
274
<replaceable>PLUGIN</replaceable>. This is only useful to
275
undo a previous <option>--disable</option> option, maybe
276
from the configuration file.
282
194
<term><option>--groupid
283
195
<replaceable>ID</replaceable></option></term>
286
Change to group ID <replaceable>ID</replaceable> on
287
startup. The default is 65534. All plugins will be
288
started using this group ID. <emphasis>Note:</emphasis>
289
This must be a number, not a name.
198
Group ID the plugins will run as
295
204
<term><option>--userid
296
205
<replaceable>ID</replaceable></option></term>
299
Change to user ID <replaceable>ID</replaceable> on
300
startup. The default is 65534. All plugins will be
301
started using this user ID. <emphasis>Note:</emphasis>
302
This must be a number, not a name.
208
User ID the plugins will run as
308
214
<term><option>--plugin-dir
309
215
<replaceable>DIRECTORY</replaceable></option></term>
312
Specify a different plugin directory. The default is
313
<filename>/lib/mandos/plugins.d</filename>, which will
314
exist in the initial <acronym>RAM</acronym> disk
321
<term><option>--config-file
322
<replaceable>FILE</replaceable></option></term>
325
Specify a different file to read additional options from.
326
See <xref linkend="files"/>. Other command line options
327
will override options specified in the file.
218
Specify a different plugin directory
362
243
<term><option>--usage</option></term>
365
Gives a short usage message.
246
Gives a short usage message
371
252
<term><option>--version</option></term>
372
253
<term><option>-V</option></term>
375
Prints the program version.
256
Prints the program version
382
<refsect1 id="overview">
383
<title>OVERVIEW</title>
384
<xi:include href="overview.xml"/>
386
This program will run on the client side in the initial
387
<acronym>RAM</acronym> disk environment, and is responsible for
388
getting a password. It does this by running plugins, one of
389
which will normally be the actual client program communicating
393
<refsect1 id="plugins">
394
<title>PLUGINS</title>
396
This program will get a password by running a number of
397
<firstterm>plugins</firstterm>, which are simply executable
398
programs in a directory in the initial <acronym>RAM</acronym>
399
disk environment. The default directory is
400
<filename>/lib/mandos/plugins.d</filename>, but this can be
401
changed with the <option>--plugin-dir</option> option. The
402
plugins are started in parallel, and the first plugin to output
403
a password <emphasis>and</emphasis> exit with a successful exit
404
code will make this plugin-runner output the password from that
405
plugin, stop any other plugins, and exit.
408
<refsect2 id="writing_plugins">
409
<title>WRITING PLUGINS</title>
411
A plugin is simply a program which prints a password to its
412
standard output and then exits with a successful (zero) exit
413
status. If the exit status is not zero, any output on
414
standard output will be ignored by the plugin runner. Any
415
output on its standard error channel will simply be passed to
416
the standard error of the plugin runner, usually the system
420
If the password is a single-line, manually entered passprase,
421
a final trailing newline character should
422
<emphasis>not</emphasis> be printed.
425
The plugin will run in the initial RAM disk environment, so
426
care must be taken not to depend on any files or running
427
services not available there.
430
The plugin must exit cleanly and free all allocated resources
431
upon getting the TERM signal, since this is what the plugin
432
runner uses to stop all other plugins when one plugin has
433
output a password and exited cleanly.
436
The plugin must not use resources, like for instance reading
437
from the standard input, without knowing that no other plugin
441
It is useful, but not required, for the plugin to take the
442
<option>--debug</option> option.
447
<refsect1 id="fallback">
448
<title>FALLBACK</title>
450
If no plugins succeed, this program will, as a fallback, ask for
451
a password on the console using <citerefentry><refentrytitle
452
>getpass</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
453
and output it. This is not meant to be the normal mode of
454
operation, as there is a separate plugin for getting a password
459
263
<refsect1 id="exit_status">
460
264
<title>EXIT STATUS</title>
462
Exit status of this program is zero if no errors were
463
encountered, and otherwise not. The fallback (see <xref
464
linkend="fallback"/>) may or may not have succeeded in either
469
<refsect1 id="environment">
470
<title>ENVIRONMENT</title>
472
This program does not use any environment variables itself, it
473
only passes on its environment to all the plugins. The
474
environment passed to plugins can be modified using the
475
<option>--global-env</option> and <option>--env-for</option>
480
<refsect1 id="files">
481
270
<title>FILES</title>
486
>/conf/conf.d/mandos/plugin-runner.conf</filename></term>
489
Since this program will be run as a keyscript, there is
490
little to no opportunity to pass command line arguments
491
to it. Therefore, it will <emphasis>also</emphasis>
492
read this file and use its contents as
493
whitespace-separated command line options. Also,
494
everything from a <quote>#</quote> character to the end
495
of a line is ignored.
498
This program is meant to run in the initial RAM disk
499
environment, so that is where this file is assumed to
500
exist. The file does not need to exist in the normal
504
This file will be processed <emphasis>before</emphasis>
505
the normal command line options, so the latter can
506
override the former, if need be.
509
This file name is the default; the file to read for
510
arguments can be changed using the
511
<option>--config-file</option> option.
275
<refsect1 id="notes">
519
281
<refsect1 id="bugs">
520
282
<title>BUGS</title>
522
The <option>--config-file</option> option is ignored when
523
specified from within a configuration file.
527
287
<refsect1 id="examples">
528
288
<title>EXAMPLE</title>
531
Normal invocation needs no options:
534
<userinput>&COMMANDNAME;</userinput>
539
Run the program, but not the plugins, in debug mode:
543
<!-- do not wrap this line -->
544
<userinput>&COMMANDNAME; --debug</userinput>
550
Run all plugins, but run the <quote>foo</quote> plugin in
555
<!-- do not wrap this line -->
556
<userinput>&COMMANDNAME; --options-for=foo:--debug</userinput>
562
Run all plugins, but not the program, in debug mode:
566
<!-- do not wrap this line -->
567
<userinput>&COMMANDNAME; --global-options=--debug</userinput>
573
Run plugins from a different directory, read a different
574
configuration file, and add two options to the
575
<citerefentry><refentrytitle >mandos-client</refentrytitle>
576
<manvolnum>8mandos</manvolnum></citerefentry> plugin:
580
<!-- do not wrap this line -->
581
<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>
586
293
<refsect1 id="security">
587
294
<title>SECURITY</title>
589
This program will, when starting, try to switch to another user.
590
If it is started as root, it will succeed, and will by default
591
switch to user and group 65534, which are assumed to be
592
non-privileged. This user and group is then what all plugins
593
will be started as. Therefore, the only way to run a plugin as
594
a privileged user is to have the set-user-ID or set-group-ID bit
595
set on the plugin executable file (see <citerefentry>
596
<refentrytitle>execve</refentrytitle><manvolnum>2</manvolnum>
600
If this program is used as a keyscript in <citerefentry
601
><refentrytitle>crypttab</refentrytitle><manvolnum>5</manvolnum>
602
</citerefentry>, there is a slight risk that if this program
603
fails to work, there might be no way to boot the system except
604
for booting from another media and editing the initial RAM disk
605
image to not run this program. This is, however, unlikely,
606
since the <citerefentry><refentrytitle
607
>password-prompt</refentrytitle><manvolnum>8mandos</manvolnum>
608
</citerefentry> plugin will read a password from the console in
609
case of failure of the other plugins, and this plugin runner
610
will also, in case of catastrophic failure, itself fall back to
611
asking and outputting a password on the console (see <xref
612
linkend="fallback"/>).
616
299
<refsect1 id="see_also">
617
300
<title>SEE ALSO</title>
619
302
<citerefentry><refentrytitle>cryptsetup</refentrytitle>
620
303
<manvolnum>8</manvolnum></citerefentry>,
621
<citerefentry><refentrytitle>crypttab</refentrytitle>
622
<manvolnum>5</manvolnum></citerefentry>,
623
<citerefentry><refentrytitle>execve</refentrytitle>
624
<manvolnum>2</manvolnum></citerefentry>,
625
304
<citerefentry><refentrytitle>mandos</refentrytitle>
626
305
<manvolnum>8</manvolnum></citerefentry>,
627
306
<citerefentry><refentrytitle>password-prompt</refentrytitle>
628
307
<manvolnum>8mandos</manvolnum></citerefentry>,
629
<citerefentry><refentrytitle>mandos-client</refentrytitle>
308
<citerefentry><refentrytitle>password-request</refentrytitle>
630
309
<manvolnum>8mandos</manvolnum></citerefentry>
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