systemd-ask-password(1) — Linux manual page


SYSTEMD-ASK-PASSWORD(1)     systemd-ask-password     SYSTEMD-ASK-PASSWORD(1)

NAME         top

       systemd-ask-password - Query the user for a system password

SYNOPSIS         top

       systemd-ask-password [OPTIONS...] [MESSAGE]

DESCRIPTION         top

       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

       ·   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 —

       ·   A TTY agent that is temporarily spawned during systemctl(1)

       ·   A command line agent which can be started temporarily to process
           queued password requests — systemd-tty-ask-password-agent

       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         top

       The following options are understood:

           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].

           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:

           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"

           Specify the query timeout in seconds. Defaults to 90s. A timeout
           of 0 waits indefinitely.

           Echo the user input instead of masking it. This is useful when
           using systemd-ask-password to query for usernames.

           Never ask for password on current TTY even if one is available.
           Always use agent system.

           If passed, accept cached passwords, i.e. passwords previously

           When used in conjunction with --accept-cached accept multiple
           passwords. This will output one password per line.

           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.

       -h, --help
           Print a short help text and exit.

EXIT STATUS         top

       On success, 0 is returned, a non-zero failure code otherwise.

SEE ALSO         top

       systemd(1), systemd-ask-password-console.service(8),
       systemd-tty-ask-password-agent(1), keyctl(1), plymouth(8), wall(1)

NOTES         top

        1. systemd Password Agent Specification

        2. XDG Icon Naming Specification

COLOPHON         top

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       ⟨⟩.  This
       page was obtained from the project's upstream Git repository
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systemd 245                                          SYSTEMD-ASK-PASSWORD(1)

Pages that refer to this page: systemd-tty-ask-password-agent(1)30-systemd-environment-d-generator(7)systemd.directives(7)systemd.index(7)