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e287086b | 1 | <?xml version='1.0'?> <!--*- Mode: nxml; nxml-child-indent: 2; indent-tabs-mode: nil -*--> |
f3bc7fdc | 2 | <!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN" |
12b42c76 | 3 | "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd"> |
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4 | |
5 | <!-- | |
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6 | SPDX-License-Identifier: LGPL-2.1+ |
7 | ||
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8 | This file is part of systemd. |
9 | ||
10 | Copyright 2011 Lennart Poettering | |
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11 | --> |
12 | ||
dfdebb1b | 13 | <refentry id="systemd-ask-password" |
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14 | xmlns:xi="http://www.w3.org/2001/XInclude"> |
15 | ||
16 | <refentryinfo> | |
17 | <title>systemd-ask-password</title> | |
18 | <productname>systemd</productname> | |
19 | ||
20 | <authorgroup> | |
21 | <author> | |
22 | <contrib>Developer</contrib> | |
23 | <firstname>Lennart</firstname> | |
24 | <surname>Poettering</surname> | |
25 | <email>lennart@poettering.net</email> | |
26 | </author> | |
27 | </authorgroup> | |
28 | </refentryinfo> | |
29 | ||
30 | <refmeta> | |
31 | <refentrytitle>systemd-ask-password</refentrytitle> | |
32 | <manvolnum>1</manvolnum> | |
33 | </refmeta> | |
34 | ||
35 | <refnamediv> | |
36 | <refname>systemd-ask-password</refname> | |
37 | <refpurpose>Query the user for a system password</refpurpose> | |
38 | </refnamediv> | |
39 | ||
40 | <refsynopsisdiv> | |
41 | <cmdsynopsis> | |
42 | <command>systemd-ask-password <arg choice="opt" rep="repeat">OPTIONS</arg> <arg choice="opt">MESSAGE</arg></command> | |
43 | </cmdsynopsis> | |
44 | </refsynopsisdiv> | |
45 | ||
46 | <refsect1> | |
47 | <title>Description</title> | |
48 | ||
49 | <para><command>systemd-ask-password</command> may be used to query | |
50 | a system password or passphrase from the user, using a question | |
51 | message specified on the command line. When run from a TTY it will | |
52 | query a password on the TTY and print it to standard output. When | |
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53 | run with no TTY or with <option>--no-tty</option> it will use the |
54 | system-wide query mechanism, which allows active users to respond via | |
55 | several agents, listed below.</para> | |
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56 | |
57 | <para>The purpose of this tool is to query system-wide passwords | |
ccddd104 | 58 | — that is passwords not attached to a specific user account. |
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59 | Examples include: unlocking encrypted hard disks when they are |
60 | plugged in or at boot, entering an SSL certificate passphrase for | |
61 | web and VPN servers.</para> | |
62 | ||
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63 | <para>Existing agents are: |
64 | <itemizedlist> | |
65 | ||
66 | <listitem><para>A boot-time password agent asking the user for | |
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67 | passwords using |
68 | <citerefentry project='die-net'><refentrytitle>plymouth</refentrytitle><manvolnum>8</manvolnum></citerefentry>, | |
69 | </para></listitem> | |
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70 | |
71 | <listitem><para>A boot-time password agent querying the user | |
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72 | directly on the console — |
73 | <citerefentry><refentrytitle>systemd-ask-password-console.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>, | |
74 | </para></listitem> | |
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75 | |
76 | <listitem><para>An agent requesting password input via a | |
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77 | <citerefentry project='man-pages'><refentrytitle>wall</refentrytitle><manvolnum>1</manvolnum></citerefentry> |
78 | message — | |
79 | <citerefentry><refentrytitle>systemd-ask-password-wall.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>, | |
80 | </para></listitem> | |
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81 | |
82 | <listitem><para>A TTY agent that is temporarily spawned during | |
83 | <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>1</manvolnum></citerefentry> | |
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84 | invocations,</para></listitem> |
85 | ||
86 | <listitem><para>A command line agent which can be started | |
87 | temporarily to process queued password | |
88 | requests — <command>systemd-tty-ask-password-agent --query</command>. | |
89 | </para></listitem> | |
e287086b | 90 | </itemizedlist></para> |
798d3a52 | 91 | |
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92 | <para>Answering system-wide password queries is a privileged operation, hence |
93 | all the agents listed above (except for the last one), run as privileged | |
94 | system services. The last one also needs elevated privileges, so | |
95 | should be run through | |
96 | <citerefentry project='die-net'><refentrytitle>sudo</refentrytitle><manvolnum>8</manvolnum></citerefentry> | |
97 | or similar.</para> | |
98 | ||
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99 | <para>Additional password agents may be implemented according to |
100 | the <ulink | |
28a0ad81 | 101 | url="https://www.freedesktop.org/wiki/Software/systemd/PasswordAgents">systemd |
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102 | Password Agent Specification</ulink>.</para> |
103 | ||
104 | <para>If a password is queried on a TTY, the user may press TAB to | |
105 | hide the asterisks normally shown for each character typed. | |
106 | Pressing Backspace as first key achieves the same effect.</para> | |
107 | ||
108 | </refsect1> | |
109 | ||
110 | <refsect1> | |
111 | <title>Options</title> | |
112 | ||
113 | <para>The following options are understood:</para> | |
114 | ||
115 | <variablelist> | |
116 | <varlistentry> | |
117 | <term><option>--icon=</option></term> | |
118 | ||
119 | <listitem><para>Specify an icon name alongside the password | |
120 | query, which may be used in all agents supporting graphical | |
121 | display. The icon name should follow the <ulink | |
122 | url="http://standards.freedesktop.org/icon-naming-spec/icon-naming-spec-latest.html">XDG | |
123 | Icon Naming Specification</ulink>.</para></listitem> | |
124 | </varlistentry> | |
125 | ||
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126 | <varlistentry> |
127 | <term><option>--id=</option></term> | |
128 | <listitem><para>Specify an identifier for this password | |
129 | query. This identifier is freely choosable and allows | |
130 | recognition of queries by involved agents. It should include | |
131 | the subsystem doing the query and the specific object the | |
132 | query is done for. Example: | |
133 | <literal>--id=cryptsetup:/dev/sda5</literal>.</para></listitem> | |
134 | </varlistentry> | |
135 | ||
136 | <varlistentry> | |
137 | <term><option>--keyname=</option></term> | |
138 | <listitem><para>Configure a kernel keyring key name to use as | |
139 | cache for the password. If set, then the tool will try to push | |
140 | any collected passwords into the kernel keyring of the root | |
141 | user, as a key of the specified name. If combined with | |
b938cb90 | 142 | <option>--accept-cached</option>, it will also try to retrieve |
a8eaaee7 | 143 | such cached passwords from the key in the kernel keyring |
b938cb90 | 144 | instead of querying the user right away. By using this option, |
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145 | the kernel keyring may be used as effective cache to avoid |
146 | repeatedly asking users for passwords, if there are multiple | |
147 | objects that may be unlocked with the same password. The | |
148 | cached key will have a timeout of 2.5min set, after which it | |
149 | will be purged from the kernel keyring. Note that it is | |
150 | possible to cache multiple passwords under the same keyname, | |
151 | in which case they will be stored as NUL-separated list of | |
152 | passwords. Use | |
524f3e5c | 153 | <citerefentry project='die-net'><refentrytitle>keyctl</refentrytitle><manvolnum>1</manvolnum></citerefentry> |
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154 | to access the cached key via the kernel keyring |
155 | directly. Example: <literal>--keyname=cryptsetup</literal></para></listitem> | |
156 | </varlistentry> | |
157 | ||
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158 | <varlistentry> |
159 | <term><option>--timeout=</option></term> | |
160 | ||
161 | <listitem><para>Specify the query timeout in seconds. Defaults | |
162 | to 90s. A timeout of 0 waits indefinitely. </para></listitem> | |
163 | </varlistentry> | |
164 | ||
165 | <varlistentry> | |
166 | <term><option>--echo</option></term> | |
167 | ||
168 | <listitem><para>Echo the user input instead of masking it. | |
169 | This is useful when using | |
170 | <filename>systemd-ask-password</filename> to query for | |
171 | usernames. </para></listitem> | |
172 | </varlistentry> | |
173 | ||
174 | <varlistentry> | |
175 | <term><option>--no-tty</option></term> | |
176 | ||
177 | <listitem><para>Never ask for password on current TTY even if | |
178 | one is available. Always use agent system.</para></listitem> | |
179 | </varlistentry> | |
180 | ||
181 | <varlistentry> | |
182 | <term><option>--accept-cached</option></term> | |
183 | ||
184 | <listitem><para>If passed, accept cached passwords, i.e. | |
a8eaaee7 | 185 | passwords previously entered.</para></listitem> |
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186 | </varlistentry> |
187 | ||
188 | <varlistentry> | |
189 | <term><option>--multiple</option></term> | |
190 | ||
191 | <listitem><para>When used in conjunction with | |
192 | <option>--accept-cached</option> accept multiple passwords. | |
193 | This will output one password per line.</para></listitem> | |
194 | </varlistentry> | |
195 | ||
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196 | <varlistentry> |
197 | <term><option>--no-output</option></term> | |
198 | ||
199 | <listitem><para>Do not print passwords to standard output. | |
200 | This is useful if you want to store a password in kernel | |
201 | keyring with <option>--keyname</option> but do not want it | |
202 | to show up on screen or in logs.</para></listitem> | |
203 | </varlistentry> | |
204 | ||
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205 | <xi:include href="standard-options.xml" xpointer="help" /> |
206 | </variablelist> | |
207 | ||
208 | </refsect1> | |
209 | ||
210 | <refsect1> | |
211 | <title>Exit status</title> | |
212 | ||
213 | <para>On success, 0 is returned, a non-zero failure code | |
214 | otherwise.</para> | |
215 | </refsect1> | |
216 | ||
217 | <refsect1> | |
218 | <title>See Also</title> | |
219 | <para> | |
220 | <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>, | |
c65aafbb | 221 | <citerefentry><refentrytitle>systemd-ask-password-console.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>, |
3f1dc090 | 222 | <citerefentry><refentrytitle>systemd-tty-ask-password-agent</refentrytitle><manvolnum>1</manvolnum></citerefentry>, |
524f3e5c | 223 | <citerefentry project='die-net'><refentrytitle>keyctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>, |
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224 | <citerefentry project='die-net'><refentrytitle>plymouth</refentrytitle><manvolnum>8</manvolnum></citerefentry>, |
225 | <citerefentry project='man-pages'><refentrytitle>wall</refentrytitle><manvolnum>1</manvolnum></citerefentry> | |
226 | </para> | |
227 | </refsect1> | |
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228 | |
229 | </refentry> |