NAME
systemd-ask-password - Query the user for a system passwordSYNOPSIS
systemd-ask-password
[OPTIONS...] [MESSAGE]
DESCRIPTION
systemd-ask-password may be used to query a system password or passphrase from the user, using a question message 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 the system-wide query mechanism, which allows active users to respond via several agents, listed below. The purpose of this tool is to query system-wide passwords — that is passwords not attached 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 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 sudo(8) 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.
OPTIONS
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".
--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"
--credential=
Configure a credential to read the password
from – if it exists. This may be used in conjunction with the
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.
--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).
--echo, -e
Equivalent to --echo=yes, see
above.
--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.
--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.
-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.
-h, --help
Print a short help text and exit.
EXIT STATUS
On success, 0 is returned, a non-zero failure code otherwise.SEE ALSO
systemd(1), systemd-ask-password-console.service(8), systemd-tty-ask-password-agent(1), keyctl(1), plymouth(8), wall(1)NOTES
- 1.
- systemd Password Agent Specification
- 2.
- XDG Icon Naming Specification
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