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Viewing changes to dracut-module/password-agent.xml

  • Committer: Teddy Hogeborn
  • Date: 2024-09-09 04:24:39 UTC
  • Revision ID: teddy@recompile.se-20240909042439-j85mr20uli2hnyis
Eliminate compiler warnings

Many programs use nested functions, which now result in a linker
warning about executable stack.  Hide this warning.  Also, rewrite a
loop in the plymouth plugin to avoid warning about signed overflow.
This change also makes the plugin pick the alphabetically first
process entry instead of the last, in case many plymouth processes are
found (which should be unlikely).

* Makefile (plugin-runner, dracut-module/password-agent,
  plugins.d/password-prompt, plugins.d/mandos-client,
  plugins.d/plymouth): New target; set LDFLAGS to add "-Xlinker
  --no-warn-execstack".
* plugins.d/plymouth.c (get_pid): When no pid files are found, and we
  are looking through the process list, go though it from the start
  instead of from the end, i.e. in normal alphabetical order and not
  in reverse order.

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Lines of Context:
dracut-module/password-agent.xml
 
1
<?xml version="1.0" encoding="UTF-8"?>
 
2
<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN"
 
3
        "http://www.oasis-open.org/docbook/xml/4.5/docbookx.dtd" [
 
4
<!ENTITY COMMANDNAME "password-agent">
 
5
<!ENTITY TIMESTAMP "2020-09-16">
 
6
<!ENTITY % common SYSTEM "../common.ent">
 
7
%common;
 
8
]>
 
9
 
 
10
<refentry xmlns:xi="http://www.w3.org/2001/XInclude">
 
11
  <refentryinfo>
 
12
    <title>Mandos Manual</title>
 
13
    <!-- Nwalsh’s docbook scripts use this to generate the footer: -->
 
14
    <productname>Mandos</productname>
 
15
    <productnumber>&version;</productnumber>
 
16
    <date>&TIMESTAMP;</date>
 
17
    <authorgroup>
 
18
      <author>
 
19
        <firstname>Björn</firstname>
 
20
        <surname>Påhlsson</surname>
 
21
        <address>
 
22
          <email>belorn@recompile.se</email>
 
23
        </address>
 
24
      </author>
 
25
      <author>
 
26
        <firstname>Teddy</firstname>
 
27
        <surname>Hogeborn</surname>
 
28
        <address>
 
29
          <email>teddy@recompile.se</email>
 
30
        </address>
 
31
      </author>
 
32
    </authorgroup>
 
33
    <copyright>
 
34
      <year>2019</year>
 
35
      <year>2020</year>
 
36
      <holder>Teddy Hogeborn</holder>
 
37
      <holder>Björn Påhlsson</holder>
 
38
    </copyright>
 
39
    <xi:include href="../legalnotice.xml"/>
 
40
  </refentryinfo>
 
41
 
 
42
  <refmeta>
 
43
    <refentrytitle>&COMMANDNAME;</refentrytitle>
 
44
    <manvolnum>8mandos</manvolnum>
 
45
  </refmeta>
 
46
 
 
47
  <refnamediv>
 
48
    <refname><command>&COMMANDNAME;</command></refname>
 
49
    <refpurpose>
 
50
      Run Mandos client as a systemd password agent.
 
51
    </refpurpose>
 
52
  </refnamediv>
 
53
 
 
54
  <refsynopsisdiv>
 
55
    <cmdsynopsis>
 
56
      <command>&COMMANDNAME;</command>
 
57
      <arg><option>--agent-directory=<replaceable
 
58
      >DIRECTORY</replaceable></option></arg>
 
59
      <sbr/>
 
60
      <arg><option>--helper-directory=<replaceable
 
61
      >DIRECTORY</replaceable></option></arg>
 
62
      <sbr/>
 
63
      <!-- <arg><option>-\-plugin-helper-dir=<replaceable -->
 
64
      <!-- >DIRECTORY</replaceable></option></arg> -->
 
65
      <!-- <sbr/> -->
 
66
      <arg><option>--user=<replaceable
 
67
      >USERID</replaceable></option></arg>
 
68
      <sbr/>
 
69
      <!-- <arg><option>-\-userid=<replaceable -->
 
70
      <!-- >ID</replaceable></option></arg> -->
 
71
      <!-- <sbr/> -->
 
72
      <arg><option>--group=<replaceable
 
73
      >GROUPID</replaceable></option></arg>
 
74
      <sbr/>
 
75
      <!-- <arg><option>-\-groupid=<replaceable -->
 
76
      <!-- >ID</replaceable></option></arg> -->
 
77
      <!-- <sbr/> -->
 
78
      <arg>--</arg>
 
79
      <arg>
 
80
        <replaceable>MANDOS_CLIENT</replaceable>
 
81
        <group rep="repeat">
 
82
          <arg choice="plain"><replaceable>OPTIONS</replaceable></arg>
 
83
        </group>
 
84
      </arg>
 
85
    </cmdsynopsis>
 
86
    <cmdsynopsis>
 
87
      <command>&COMMANDNAME;</command>
 
88
      <arg choice="plain"><option>--test</option></arg>
 
89
    </cmdsynopsis>
 
90
    <cmdsynopsis>
 
91
      <command>&COMMANDNAME;</command>
 
92
      <group choice="req">
 
93
        <arg choice="plain"><option>--help</option></arg>
 
94
        <arg choice="plain"><option>-?</option></arg>
 
95
      </group>
 
96
    </cmdsynopsis>
 
97
    <cmdsynopsis>
 
98
      <command>&COMMANDNAME;</command>
 
99
      <arg choice="plain"><option>--usage</option></arg>
 
100
    </cmdsynopsis>
 
101
    <cmdsynopsis>
 
102
      <command>&COMMANDNAME;</command>
 
103
      <group choice="req">
 
104
        <arg choice="plain"><option>--version</option></arg>
 
105
        <arg choice="plain"><option>-V</option></arg>
 
106
      </group>
 
107
    </cmdsynopsis>
 
108
  </refsynopsisdiv>
 
109
 
 
110
  <refsect1 id="description">
 
111
    <title>DESCRIPTION</title>
 
112
    <para>
 
113
      <command>&COMMANDNAME;</command> is a program which is meant to
 
114
      be a <citerefentry><refentrytitle>systemd</refentrytitle>
 
115
      <manvolnum>1</manvolnum></citerefentry> <quote>Password
 
116
      Agent</quote> (See <ulink
 
117
      url="https://systemd.io/PASSWORD_AGENTS/">Password
 
118
      Agents</ulink>).  The aim of this program is therefore to
 
119
      acquire and then send a password to some other program which
 
120
      will use the password to unlock the encrypted root disk.
 
121
    </para>
 
122
    <para>
 
123
      This program is not meant to be invoked directly, but can be in
 
124
      order to test it.
 
125
    </para>
 
126
  </refsect1>
 
127
 
 
128
  <refsect1 id="purpose">
 
129
    <title>PURPOSE</title>
 
130
    <para>
 
131
      The purpose of this is to enable <emphasis>remote and unattended
 
132
      rebooting</emphasis> of client host computer with an
 
133
      <emphasis>encrypted root file system</emphasis>.  See <xref
 
134
      linkend="overview"/> for details.
 
135
    </para>
 
136
  </refsect1>
 
137
 
 
138
  <refsect1>
 
139
    <title>OPTIONS</title>
 
140
    <variablelist>
 
141
 
 
142
      <varlistentry>
 
143
        <term><option>--agent-directory
 
144
        <replaceable>DIRECTORY</replaceable></option></term>
 
145
        <listitem>
 
146
          <para>
 
147
            Specify a different agent directory.  The default is
 
148
            <quote><filename class="directory"
 
149
            >/run/systemd/ask-password</filename ></quote> as per the
 
150
            <ulink url="https://systemd.io/PASSWORD_AGENTS/">Password
 
151
            Agents</ulink> specification.
 
152
          </para>
 
153
        </listitem>
 
154
      </varlistentry>
 
155
 
 
156
      <varlistentry>
 
157
        <term><option>--helper-directory
 
158
        <replaceable>DIRECTORY</replaceable></option></term>
 
159
        <listitem>
 
160
          <para>
 
161
            Specify a different helper directory.  The default is
 
162
            <quote><filename class="directory"
 
163
                             >/lib/mandos/plugin-helpers</filename
 
164
                             ></quote>, which
 
165
            will exist in the initial <acronym>RAM</acronym> disk
 
166
            environment.  (This will simply be passed to the
 
167
            <replaceable>MANDOS_CLIENT</replaceable> program via the
 
168
            <envar>MANDOSPLUGINHELPERDIR</envar> environment variable.
 
169
            See
 
170
            <citerefentry><refentrytitle>mandos-client</refentrytitle
 
171
            ><manvolnum>8mandos</manvolnum></citerefentry>.)
 
172
          </para>
 
173
        </listitem>
 
174
      </varlistentry>
 
175
 
 
176
      <varlistentry>
 
177
        <term><option>--user
 
178
        <replaceable>USERID</replaceable></option></term>
 
179
        <listitem>
 
180
          <para>
 
181
            Change real user ID to <replaceable>USERID</replaceable>
 
182
            when running <replaceable>MANDOS_CLIENT</replaceable>.
 
183
            The default is 65534.  <emphasis>Note:</emphasis> This
 
184
            must be a number, not a name.
 
185
          </para>
 
186
        </listitem>
 
187
      </varlistentry>
 
188
 
 
189
      <varlistentry>
 
190
        <term><option>--group
 
191
        <replaceable>GROUPID</replaceable></option></term>
 
192
        <listitem>
 
193
          <para>
 
194
            Change real group ID to <replaceable>GROUPID</replaceable>
 
195
            when running <replaceable>MANDOS_CLIENT</replaceable>.
 
196
            The default is 65534.  <emphasis>Note:</emphasis> This
 
197
            must be a number, not a name.
 
198
          </para>
 
199
        </listitem>
 
200
      </varlistentry>
 
201
 
 
202
      <varlistentry>
 
203
        <term><replaceable>MANDOS_CLIENT</replaceable></term>
 
204
        <listitem>
 
205
          <para>
 
206
            This specifies the file name for
 
207
            <citerefentry><refentrytitle>mandos-client</refentrytitle
 
208
            ><manvolnum>8mandos</manvolnum></citerefentry>.  If the
 
209
            <quote><option>--</option></quote> option is given, any
 
210
            following options are passed to the <replaceable
 
211
            >MANDOS_CLIENT</replaceable> program.  The default is
 
212
            <quote><filename
 
213
            >/lib/mandos/plugins.d/mandos-client</filename ></quote>
 
214
            (which is the correct location for the initial
 
215
            <acronym>RAM</acronym> disk environment) without any
 
216
            options.
 
217
          </para>
 
218
        </listitem>
 
219
      </varlistentry>
 
220
 
 
221
      <varlistentry>
 
222
        <term><option>--help</option></term>
 
223
        <term><option>-?</option></term>
 
224
        <listitem>
 
225
          <para>
 
226
            Gives a help message about options and their meanings.
 
227
          </para>
 
228
        </listitem>
 
229
      </varlistentry>
 
230
 
 
231
      <varlistentry>
 
232
        <term><option>--test</option></term>
 
233
        <listitem>
 
234
          <para>
 
235
            Ignore normal operation; instead only run self-tests.
 
236
            Adding the <option>--help</option> option may show more
 
237
            options possible in combination with
 
238
            <option>--test</option>.
 
239
          </para>
 
240
        </listitem>
 
241
      </varlistentry>
 
242
 
 
243
      <varlistentry>
 
244
        <term><option>--usage</option></term>
 
245
        <listitem>
 
246
          <para>
 
247
            Gives a short usage message.
 
248
          </para>
 
249
        </listitem>
 
250
      </varlistentry>
 
251
 
 
252
      <varlistentry>
 
253
        <term><option>--version</option></term>
 
254
        <term><option>-V</option></term>
 
255
        <listitem>
 
256
          <para>
 
257
            Prints the program version.
 
258
          </para>
 
259
        </listitem>
 
260
      </varlistentry>
 
261
    </variablelist>
 
262
  </refsect1>
 
263
 
 
264
  <refsect1 id="overview">
 
265
    <title>OVERVIEW</title>
 
266
    <xi:include href="../overview.xml"/>
 
267
    <para>
 
268
      This program, &COMMANDNAME;, will run on the client side in the
 
269
      initial <acronym>RAM</acronym> disk environment, and is
 
270
      responsible for getting a password from the Mandos client
 
271
      program itself, and to send that password to whatever is
 
272
      currently asking for a password using the systemd <ulink
 
273
      url="https://systemd.io/PASSWORD_AGENTS/">Password
 
274
      Agents</ulink> mechanism.
 
275
    </para>
 
276
    <para>To accomplish this, &COMMANDNAME; runs the
 
277
    <command>mandos-client</command> program (which is the actual
 
278
    client program communicating with the Mandos server) or,
 
279
    alternatively, any executable file specified as
 
280
    <replaceable>MANDOS_CLIENT</replaceable>, and, as soon as a
 
281
    password is acquired from the
 
282
    <replaceable>MANDOS_CLIENT</replaceable> program, sends that
 
283
    password (as per the <ulink
 
284
    url="https://systemd.io/PASSWORD_AGENTS/">Password Agents</ulink>
 
285
    specification) to all currently unanswered password questions.
 
286
    </para>
 
287
    <para>
 
288
      This program should be started (normally as a systemd service,
 
289
      which in turn is normally started by a <citerefentry
 
290
      ><refentrytitle>systemd.path</refentrytitle>
 
291
      <manvolnum>5</manvolnum></citerefentry> file) as a reaction to
 
292
      files named <quote><filename>ask.<replaceable>xxxx</replaceable
 
293
      ></filename></quote> appearing in the agent directory
 
294
      <quote><filename
 
295
      class="directory">/run/systemd/ask-password</filename></quote>
 
296
      (or the directory specified by
 
297
      <option>--agent-directory</option>).
 
298
    </para>
 
299
  </refsect1>
 
300
 
 
301
  <refsect1 id="exit_status">
 
302
    <title>EXIT STATUS</title>
 
303
    <para>
 
304
      Exit status of this program is zero if no errors were
 
305
      encountered, and otherwise not.
 
306
    </para>
 
307
  </refsect1>
 
308
 
 
309
  <refsect1 id="environment">
 
310
    <title>ENVIRONMENT</title>
 
311
    <para>
 
312
      This program does not use any environment variables itself, it
 
313
      only passes on its environment to
 
314
      <replaceable>MANDOS_CLIENT</replaceable>.  Also, the
 
315
      <option>--helper-directory</option> option will affect the
 
316
      environment variable <envar>MANDOSPLUGINHELPERDIR</envar> for
 
317
      <replaceable>MANDOS_CLIENT</replaceable>.
 
318
    </para>
 
319
  </refsect1>
 
320
 
 
321
  <refsect1 id="files">
 
322
    <title>FILES</title>
 
323
    <para>
 
324
      <variablelist>
 
325
        <varlistentry>
 
326
          <term><filename class="directory"
 
327
                          >/run/systemd/ask-password</filename></term>
 
328
          <listitem>
 
329
            <para>
 
330
              The default directory to watch for password questions as
 
331
              per the <ulink
 
332
              url="https://systemd.io/PASSWORD_AGENTS/">Password
 
333
              Agents</ulink> specification; can be changed by the
 
334
              <option>--agent-directory</option> option.
 
335
            </para>
 
336
          </listitem>
 
337
        </varlistentry>
 
338
        <varlistentry>
 
339
          <term><filename class="directory"
 
340
                          >/lib/mandos/plugin-helpers</filename
 
341
                          ></term>
 
342
          <listitem>
 
343
            <para>
 
344
              The helper directory as supplied to
 
345
              <replaceable>MANDOS_CLIENT</replaceable> via the
 
346
              <envar>MANDOSPLUGINHELPERDIR</envar> environment
 
347
              variable; can be changed by the
 
348
              <option>--helper-directory</option> option.
 
349
            </para>
 
350
          </listitem>
 
351
        </varlistentry>
 
352
      </variablelist>
 
353
    </para>
 
354
  </refsect1>
 
355
 
 
356
  <refsect1 id="bugs">
 
357
    <title>BUGS</title>
 
358
    <xi:include href="../bugs.xml"/>
 
359
  </refsect1>
 
360
 
 
361
  <refsect1 id="examples">
 
362
    <title>EXAMPLE</title>
 
363
    <informalexample>
 
364
      <para>
 
365
        Normal invocation needs no options:
 
366
      </para>
 
367
      <para>
 
368
        <userinput>&COMMANDNAME;</userinput>
 
369
      </para>
 
370
    </informalexample>
 
371
    <informalexample>
 
372
      <para>
 
373
        Run an alternative <replaceable>MANDOS_CLIENT</replaceable>
 
374
        program::
 
375
      </para>
 
376
      <para>
 
377
        <userinput>&COMMANDNAME; /usr/local/sbin/alternate</userinput>
 
378
      </para>
 
379
    </informalexample>
 
380
    <informalexample>
 
381
      <para>
 
382
        Use alternative locations for the helper directory and the
 
383
        Mandos client, and add extra options suitable for running in
 
384
        the normal file system:
 
385
      </para>
 
386
      <para>
 
387
        
 
388
        <!-- do not wrap this line -->
 
389
        <userinput>&COMMANDNAME; --helper-directory=/usr/lib/x86_64-linux-gnu/mandos/plugin-helpers -- /usr/lib/x86_64-linux-gnu/mandos/plugins.d/mandos-client --pubkey=/etc/keys/mandos/pubkey.txt --seckey=/etc/keys/mandos/seckey.txt --tls-pubkey=/etc/keys/mandos/tls-pubkey.pem --tls-privkey=/etc/keys/mandos/tls-privkey.pem</userinput>
 
390
        
 
391
      </para>
 
392
    </informalexample>
 
393
    <informalexample>
 
394
      <para>
 
395
        Use the default location for
 
396
        <citerefentry><refentrytitle>mandos-client</refentrytitle>
 
397
        <manvolnum>8mandos</manvolnum></citerefentry>, but add many
 
398
        options to it:
 
399
      </para>
 
400
      <para>
 
401
 
 
402
<!-- do not wrap this line -->
 
403
<userinput>&COMMANDNAME; -- /lib/mandos/plugins.d/mandos-client --pubkey=/etc/mandos/keys/pubkey.txt --seckey=/etc/mandos/keys/seckey.txt --tls-pubkey=/etc/mandos/keys/tls-pubkey.pem --tls-privkey=/etc/mandos/keys/tls-privkey.pem</userinput>
 
404
 
 
405
      </para>
 
406
    </informalexample>
 
407
    <informalexample>
 
408
      <para>
 
409
        Only run the self-tests:
 
410
      </para>
 
411
      <para>
 
412
        <userinput>&COMMANDNAME; --test</userinput>
 
413
      </para>
 
414
    </informalexample>
 
415
  </refsect1>
 
416
  <refsect1 id="security">
 
417
    <title>SECURITY</title>
 
418
    <para>
 
419
      This program will need to run as the root user in order to read
 
420
      the agent directory and the <quote><filename
 
421
      >ask.<replaceable>xxxx</replaceable></filename></quote> files
 
422
      there, and will, when starting the Mandos client program,
 
423
      require the ability to set the <quote>real</quote> user and
 
424
      group ids to another user, by default user and group 65534,
 
425
      which are assumed to be non-privileged.  This is done in order
 
426
      to match the expectations of <citerefentry><refentrytitle
 
427
      >mandos-client</refentrytitle><manvolnum>8mandos</manvolnum
 
428
      ></citerefentry>, which assumes that its executable file is
 
429
      owned by the root user and also has the set-user-ID bit set (see
 
430
      <citerefentry><refentrytitle>execve</refentrytitle><manvolnum
 
431
      >2</manvolnum></citerefentry>).
 
432
    </para>
 
433
  </refsect1>
 
434
 
 
435
  <refsect1 id="see_also">
 
436
    <title>SEE ALSO</title>
 
437
    <para>
 
438
      <citerefentry><refentrytitle>intro</refentrytitle>
 
439
      <manvolnum>8mandos</manvolnum></citerefentry>,
 
440
      <citerefentry><refentrytitle>mandos-client</refentrytitle>
 
441
      <manvolnum>8mandos</manvolnum></citerefentry>,
 
442
      <citerefentry><refentrytitle>systemd</refentrytitle>
 
443
      <manvolnum>1</manvolnum></citerefentry>,
 
444
    </para>
 
445
    <variablelist>
 
446
      <varlistentry>
 
447
        <term>
 
448
          <ulink url="https://systemd.io/PASSWORD_AGENTS/">Password
 
449
          Agents</ulink>
 
450
        </term>
 
451
        <listitem>
 
452
          <para>
 
453
            The specification for systemd <quote>Password
 
454
            Agent</quote> programs, which
 
455
            <command>&COMMANDNAME;</command> follows.
 
456
          </para>
 
457
        </listitem>
 
458
      </varlistentry>
 
459
    </variablelist>
 
460
  </refsect1>
 
461
 
 
462
</refentry>
 
463
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