/mandos/trunk

To get this branch, use:
bzr branch http://bzr.recompile.se/loggerhead/mandos/trunk

« back to all changes in this revision

Viewing changes to plugins.d/usplash.xml

  • Committer: Teddy Hogeborn
  • Date: 2017-08-20 18:53:16 UTC
  • mfrom: (910 trunk)
  • mto: This revision was merged to the branch mainline in revision 911.
  • Revision ID: teddy@recompile.se-20170820185316-3i5080cpg08f0e8q
Merge from trunk

Show diffs side-by-side

added added

removed removed

Lines of Context:
 
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 "usplash">
 
5
<!ENTITY TIMESTAMP "2017-02-23">
 
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>2008</year>
 
35
      <year>2009</year>
 
36
      <year>2010</year>
 
37
      <year>2011</year>
 
38
      <year>2012</year>
 
39
      <year>2013</year>
 
40
      <year>2014</year>
 
41
      <year>2015</year>
 
42
      <year>2016</year>
 
43
      <year>2017</year>
 
44
      <holder>Teddy Hogeborn</holder>
 
45
      <holder>Björn Påhlsson</holder>
 
46
    </copyright>
 
47
    <xi:include href="../legalnotice.xml"/>
 
48
  </refentryinfo>
 
49
  
 
50
  <refmeta>
 
51
    <refentrytitle>&COMMANDNAME;</refentrytitle>
 
52
    <manvolnum>8mandos</manvolnum>
 
53
  </refmeta>
 
54
  
 
55
  <refnamediv>
 
56
    <refname><command>&COMMANDNAME;</command></refname>
 
57
    <refpurpose>Mandos plugin to use usplash to get a
 
58
    password.</refpurpose>
 
59
  </refnamediv>
 
60
  
 
61
  <refsynopsisdiv>
 
62
    <cmdsynopsis>
 
63
      <command>&COMMANDNAME;</command>
 
64
    </cmdsynopsis>
 
65
  </refsynopsisdiv>
 
66
  
 
67
  <refsect1 id="description">
 
68
    <title>DESCRIPTION</title>
 
69
    <para>
 
70
      This program prompts for a password using <citerefentry>
 
71
      <refentrytitle>usplash</refentrytitle><manvolnum>8</manvolnum>
 
72
      </citerefentry> and outputs any given password to standard
 
73
      output.  If no <citerefentry><refentrytitle
 
74
      >usplash</refentrytitle><manvolnum>8</manvolnum></citerefentry>
 
75
      process can be found, this program will immediately exit with an
 
76
      exit code indicating failure.
 
77
    </para>
 
78
    <para>
 
79
      This program is not very useful on its own.  This program is
 
80
      really meant to run as a plugin in the <application
 
81
      >Mandos</application> client-side system, where it is used as a
 
82
      fallback and alternative to retrieving passwords from a
 
83
      <application >Mandos</application> server.
 
84
    </para>
 
85
    <para>
 
86
      If this program is killed (presumably by
 
87
      <citerefentry><refentrytitle>plugin-runner</refentrytitle>
 
88
      <manvolnum>8mandos</manvolnum></citerefentry> because some other
 
89
      plugin provided the password), it cannot tell <citerefentry>
 
90
      <refentrytitle>usplash</refentrytitle><manvolnum>8</manvolnum>
 
91
      </citerefentry> to abort requesting a password, because
 
92
      <citerefentry><refentrytitle>usplash</refentrytitle>
 
93
      <manvolnum>8</manvolnum></citerefentry> does not support this.
 
94
      Therefore, this program will then <emphasis>kill</emphasis> the
 
95
      running <citerefentry><refentrytitle>usplash</refentrytitle>
 
96
      <manvolnum>8</manvolnum></citerefentry> process and start a
 
97
      <emphasis>new</emphasis> one using the same command line
 
98
      arguments as the old one was using.
 
99
    </para>
 
100
  </refsect1>
 
101
  
 
102
  <refsect1 id="options">
 
103
    <title>OPTIONS</title>
 
104
    <para>
 
105
      This program takes no options.
 
106
    </para>
 
107
  </refsect1>
 
108
  
 
109
  <refsect1 id="exit_status">
 
110
    <title>EXIT STATUS</title>
 
111
    <para>
 
112
      If exit status is 0, the output from the program is the password
 
113
      as it was read.  Otherwise, if exit status is other than 0, the
 
114
      program was interrupted or encountered an error, and any output
 
115
      so far could be corrupt and/or truncated, and should therefore
 
116
      be ignored.
 
117
    </para>
 
118
  </refsect1>
 
119
  
 
120
  <refsect1 id="environment">
 
121
    <title>ENVIRONMENT</title>
 
122
    <variablelist>
 
123
      <varlistentry>
 
124
        <term><envar>cryptsource</envar></term>
 
125
        <term><envar>crypttarget</envar></term>
 
126
        <listitem>
 
127
          <para>
 
128
            If set, these environment variables will be assumed to
 
129
            contain the source device name and the target device
 
130
            mapper name, respectively, and will be shown as part of
 
131
            the prompt.
 
132
        </para>
 
133
        <para>
 
134
          These variables will normally be inherited from
 
135
          <citerefentry><refentrytitle>plugin-runner</refentrytitle>
 
136
          <manvolnum>8mandos</manvolnum></citerefentry>, which will
 
137
          normally have inherited them from
 
138
          <filename>/scripts/local-top/cryptroot</filename> in the
 
139
          initial <acronym>RAM</acronym> disk environment, which will
 
140
          have set them from parsing kernel arguments and
 
141
          <filename>/conf/conf.d/cryptroot</filename> (also in the
 
142
          initial RAM disk environment), which in turn will have been
 
143
          created when the initial RAM disk image was created by
 
144
          <filename
 
145
          >/usr/share/initramfs-tools/hooks/cryptroot</filename>, by
 
146
          extracting the information of the root file system from
 
147
          <filename >/etc/crypttab</filename>.
 
148
        </para>
 
149
        <para>
 
150
          This behavior is meant to exactly mirror the behavior of
 
151
          <command>askpass</command>, the default password prompter.
 
152
        </para>
 
153
        </listitem>
 
154
      </varlistentry>
 
155
    </variablelist>
 
156
  </refsect1>
 
157
  
 
158
  <refsect1 id="files">
 
159
    <title>FILES</title>
 
160
    <variablelist>
 
161
      <varlistentry>
 
162
        <term><filename>/dev/.initramfs/usplash_fifo</filename></term>
 
163
        <listitem>
 
164
          <para>
 
165
            This is the <acronym>FIFO</acronym> to where this program
 
166
            will write the commands for <citerefentry><refentrytitle
 
167
            >usplash</refentrytitle><manvolnum>8</manvolnum>
 
168
            </citerefentry>.  See <citerefentry><refentrytitle
 
169
            >fifo</refentrytitle><manvolnum>7</manvolnum>
 
170
            </citerefentry>.
 
171
          </para>
 
172
        </listitem>
 
173
      </varlistentry>
 
174
      <varlistentry>
 
175
        <term><filename>/dev/.initramfs/usplash_outfifo</filename></term>
 
176
        <listitem>
 
177
          <para>
 
178
            This is the <acronym>FIFO</acronym> where this program
 
179
            will read the password from <citerefentry><refentrytitle
 
180
            >usplash</refentrytitle><manvolnum>8</manvolnum>
 
181
            </citerefentry>.  See <citerefentry><refentrytitle
 
182
            >fifo</refentrytitle><manvolnum>7</manvolnum>
 
183
            </citerefentry>.
 
184
          </para>
 
185
        </listitem>
 
186
      </varlistentry>
 
187
      <varlistentry>
 
188
        <term><filename class="directory">/proc</filename></term>
 
189
        <listitem>
 
190
          <para>
 
191
            To find the running <citerefentry><refentrytitle
 
192
            >usplash</refentrytitle><manvolnum>8</manvolnum>
 
193
            </citerefentry>, this directory will be searched for
 
194
            numeric entries which will be assumed to be directories.
 
195
            In all those directories, the <filename>exe</filename> and
 
196
            <filename>cmdline</filename> entries will be used to
 
197
            determine the name of the running binary, effective user
 
198
            and group <abbrev>ID</abbrev>, and the command line
 
199
            arguments.  See <citerefentry><refentrytitle
 
200
            >proc</refentrytitle><manvolnum>5</manvolnum>
 
201
            </citerefentry>.
 
202
          </para>
 
203
        </listitem>
 
204
      </varlistentry>
 
205
      <varlistentry>
 
206
        <term><filename>/sbin/usplash</filename></term>
 
207
        <listitem>
 
208
          <para>
 
209
            This is the name of the binary which will be searched for
 
210
            in the process list.  See <citerefentry><refentrytitle
 
211
            >usplash</refentrytitle><manvolnum>8</manvolnum>
 
212
            </citerefentry>.
 
213
          </para>
 
214
        </listitem>
 
215
      </varlistentry>
 
216
    </variablelist>
 
217
  </refsect1>
 
218
  
 
219
  <refsect1 id="bugs">
 
220
    <title>BUGS</title>
 
221
    <para>
 
222
      Killing <citerefentry><refentrytitle>usplash</refentrytitle>
 
223
      <manvolnum>8</manvolnum></citerefentry> and starting a new one
 
224
      is ugly, but necessary as long as it does not support aborting a
 
225
      password request.
 
226
    </para>
 
227
    <xi:include href="../bugs.xml"/>
 
228
  </refsect1>
 
229
  
 
230
  <refsect1 id="example">
 
231
    <title>EXAMPLE</title>
 
232
    <para>
 
233
      Note that normally, this program will not be invoked directly,
 
234
      but instead started by the Mandos <citerefentry><refentrytitle
 
235
      >plugin-runner</refentrytitle><manvolnum>8mandos</manvolnum>
 
236
      </citerefentry>.
 
237
    </para>
 
238
    <informalexample>
 
239
      <para>
 
240
        This program takes no options.
 
241
      </para>
 
242
      <para>
 
243
        <userinput>&COMMANDNAME;</userinput>
 
244
      </para>
 
245
    </informalexample>
 
246
  </refsect1>
 
247
  
 
248
  <refsect1 id="security">
 
249
    <title>SECURITY</title>
 
250
    <para>
 
251
      If this program is killed by a signal, it will kill the process
 
252
      <abbrev>ID</abbrev> which at the start of this program was
 
253
      determined to run <citerefentry><refentrytitle
 
254
      >usplash</refentrytitle><manvolnum>8</manvolnum></citerefentry>
 
255
      as root (see also <xref linkend="files"/>).  There is a very
 
256
      slight risk that, in the time between those events, that process
 
257
      <abbrev>ID</abbrev> was freed and then taken up by another
 
258
      process; the wrong process would then be killed.  Now, this
 
259
      program can only be killed by the user who started it; see
 
260
      <citerefentry><refentrytitle>plugin-runner</refentrytitle>
 
261
      <manvolnum>8mandos</manvolnum></citerefentry>.  This program
 
262
      should therefore be started by a completely separate
 
263
      non-privileged user, and no other programs should be allowed to
 
264
      run as that special user.  This means that it is not recommended
 
265
      to use the user "nobody" to start this program, as other
 
266
      possibly less trusted programs could be running as "nobody", and
 
267
      they would then be able to kill this program, triggering the
 
268
      killing of the process <abbrev>ID</abbrev> which may or may not
 
269
      be <citerefentry><refentrytitle>usplash</refentrytitle>
 
270
      <manvolnum>8</manvolnum></citerefentry>.
 
271
    </para>
 
272
    <para>
 
273
      The only other thing that could be considered worthy of note is
 
274
      this:  This program is meant to be run by <citerefentry>
 
275
      <refentrytitle>plugin-runner</refentrytitle><manvolnum
 
276
      >8mandos</manvolnum></citerefentry>, and will, when run
 
277
      standalone, outside, in a normal environment, immediately output
 
278
      on its standard output any presumably secret password it just
 
279
      received.  Therefore, when running this program standalone
 
280
      (which should never normally be done), take care not to type in
 
281
      any real secret password by force of habit, since it would then
 
282
      immediately be shown as output.
 
283
    </para>
 
284
  </refsect1>
 
285
  
 
286
  <refsect1 id="see_also">
 
287
    <title>SEE ALSO</title>
 
288
    <para>
 
289
      <citerefentry><refentrytitle>intro</refentrytitle>
 
290
      <manvolnum>8mandos</manvolnum></citerefentry>,
 
291
      <citerefentry><refentrytitle>crypttab</refentrytitle>
 
292
      <manvolnum>5</manvolnum></citerefentry>,
 
293
      <citerefentry><refentrytitle>fifo</refentrytitle>
 
294
      <manvolnum>7</manvolnum></citerefentry>,
 
295
      <citerefentry><refentrytitle>plugin-runner</refentrytitle>
 
296
      <manvolnum>8mandos</manvolnum></citerefentry>,
 
297
      <citerefentry><refentrytitle>proc</refentrytitle>
 
298
      <manvolnum>5</manvolnum></citerefentry>,
 
299
      <citerefentry><refentrytitle>usplash</refentrytitle>
 
300
      <manvolnum>8</manvolnum></citerefentry>
 
301
    </para>
 
302
  </refsect1>
 
303
</refentry>
 
304
<!-- Local Variables: -->
 
305
<!-- time-stamp-start: "<!ENTITY TIMESTAMP [\"']" -->
 
306
<!-- time-stamp-end: "[\"']>" -->
 
307
<!-- time-stamp-format: "%:y-%02m-%02d" -->
 
308
<!-- End: -->