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HTML rendering created 2025-02-02 by Michael Kerrisk, author of The Linux Programming Interface. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH. |
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NAME | SYNOPSIS | DESCRIPTION | OPTIONS | EXIT STATUS | SEE ALSO | NOTES | COLOPHON |
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SYSTEMD-ASK-PASSWORD(1) systemd-ask-password SYSTEMD-ASK-PASSWORD(1)
systemd-ask-password - Query the user for a system password
systemd-ask-password [OPTIONS...] [MESSAGE]
systemd-ask-password may be used to query a password or passphrase
interactively from the user, using a question prompt specified on
the command line. When run from a TTY it will query a password on
the TTY and print it to standard output. When run with no TTY or
with --no-tty it will use a system-wide or per-user agent-based
query mechanism, which allows active users to respond via several
agents, listed below.
The purpose of this tool is to query system-wide or per-user
passwords — the former includes passwords possibly not associated
to a specific user account. Examples include: unlocking encrypted
hard disks when they are plugged in or at boot, entering an SSL
certificate passphrase for web and VPN servers.
Existing system-level agents are:
• A boot-time password agent asking the user for passwords using
plymouth(8),
• A boot-time password agent querying the user directly on the
console — systemd-ask-password-console.service(8),
• An agent requesting password input via a wall(1) message —
systemd-ask-password-wall.service(8),
• A TTY agent that is temporarily spawned during systemctl(1)
invocations,
• A command line agent which can be started temporarily to
process queued password requests —
systemd-tty-ask-password-agent --query.
Answering system-wide password queries is a privileged operation,
hence all the agents listed above (except for the last one), run
as privileged system services. The last one also needs elevated
privileges, so should be run through run0(1) or similar.
Additional password agents may be implemented according to the
systemd Password Agent Specification[1].
If a password is queried on a TTY, the user may press TAB to hide
the asterisks normally shown for each character typed. Pressing
Backspace as first key achieves the same effect.
The following options are understood:
--icon=
Specify an icon name alongside the password query, which may
be used in all agents supporting graphical display. The icon
name should follow the XDG Icon Naming Specification[2].
--id=
Specify an identifier for this password query. This identifier
is freely choosable and allows recognition of queries by
involved agents. It should include the subsystem doing the
query and the specific object the query is done for. Example:
"--id=cryptsetup:/dev/sda5".
Added in version 227.
--keyname=
Configure a kernel keyring key name to use as cache for the
password. If set, then the tool will try to push any collected
passwords into the kernel keyring of the root user, as a key
of the specified name. If combined with --accept-cached, it
will also try to retrieve such cached passwords from the key
in the kernel keyring instead of querying the user right away.
By using this option, the kernel keyring may be used as
effective cache to avoid repeatedly asking users for
passwords, if there are multiple objects that may be unlocked
with the same password. The cached key will have a timeout of
2.5min set, after which it will be purged from the kernel
keyring. Note that it is possible to cache multiple passwords
under the same keyname, in which case they will be stored as
NUL-separated list of passwords. Use keyctl(1) to access the
cached key via the kernel keyring directly. Example:
"--keyname=cryptsetup"
Added in version 227.
--credential=
Configure a credential to read the password from – if it
exists. This may be used in conjunction with the
ImportCredential=, LoadCredential= and SetCredential= settings
in unit files. See systemd.exec(5) for details. If not
specified, defaults to "password". This option has no effect
if no credentials directory is passed to the program (i.e.
$CREDENTIALS_DIRECTORY is not set) or if the no credential of
the specified name exists.
Added in version 249.
--timeout=
Specify the query timeout in seconds. Defaults to 90s. A
timeout of 0 waits indefinitely.
--echo=yes|no|masked
Controls whether to echo user input. Takes a boolean or the
special string "masked", the default being the latter. If
enabled the typed characters are echoed literally, which is
useful for prompting for usernames and other non-protected
data. If disabled the typed characters are not echoed in any
form, the user will not get feedback on their input. If set to
"masked", an asterisk ("*") is echoed for each character
typed. In this mode, if the user hits the tabulator key ("↹"),
echo is turned off. (Alternatively, if the user hits the
backspace key ("⌫") while no data has been entered otherwise,
echo is turned off, too).
Added in version 249.
--echo, -e
Equivalent to --echo=yes, see above.
Added in version 217.
--emoji=yes|no|auto
Controls whether or not to prefix the query with a lock and
key emoji (🔐), if the TTY settings permit this. The default
is "auto", which defaults to "yes", unless --echo=yes is
given.
Added in version 249.
--no-tty
Never ask for password on current TTY even if one is
available. Always use agent system.
--accept-cached
If passed, accept cached passwords, i.e. passwords previously
entered.
--multiple
When used in conjunction with --accept-cached accept multiple
passwords. This will output one password per line.
--no-output
Do not print passwords to standard output. This is useful if
you want to store a password in kernel keyring with --keyname=
but do not want it to show up on screen or in logs.
Added in version 230.
-n
By default, when the acquired password is written to standard
output it is suffixed by a newline character. This may be
turned off with the -n switch, similarly to the switch of the
same name of the echo(1) command.
Added in version 249.
--user, --system
Controls whether to query the system-wide or the per-user
password agents. By default if invoked privileged the
system-wide agents are queried, otherwise the per-user ones.
These options allow one to override this automatic behaviour.
Added in version 257.
-h, --help
Print a short help text and exit.
On success, 0 is returned, a non-zero failure code otherwise.
systemd(1), systemd-ask-password-console.service(8),
systemd-tty-ask-password-agent(1), keyctl(1), plymouth(8), wall(1)
1. systemd Password Agent Specification
https://systemd.io/PASSWORD_AGENTS/
2. XDG Icon Naming Specification
https://standards.freedesktop.org/icon-naming-spec/icon-naming-spec-latest.html
This page is part of the systemd (systemd system and service
manager) project. Information about the project can be found at
⟨http://www.freedesktop.org/wiki/Software/systemd⟩. If you have a
bug report for this manual page, see
⟨http://www.freedesktop.org/wiki/Software/systemd/#bugreports⟩.
This page was obtained from the project's upstream Git repository
⟨https://github.com/systemd/systemd.git⟩ on 2025-02-02. (At that
time, the date of the most recent commit that was found in the
repository was 2025-02-02.) If you discover any rendering
problems in this HTML version of the page, or you believe there is
a better or more up-to-date source for the page, or you have
corrections or improvements to the information in this COLOPHON
(which is not part of the original manual page), send a mail to
man-pages@man7.org
systemd 258~devel SYSTEMD-ASK-PASSWORD(1)
Pages that refer to this page: systemd-tty-ask-password-agent(1), systemd.directives(7), systemd.index(7), pam_systemd_loadkey(8)
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HTML rendering created 2025-02-02 by Michael Kerrisk, author of The Linux Programming Interface. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH. |
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