pam_systemd_loadkey(8) — Linux manual page

NAME \| SYNOPSIS \| DESCRIPTION \| OPTIONS \| EXAMPLE \| COLOPHON

PAM_SYSTEMD_LOADKEY(8)     pam_systemd_loadkey    PAM_SYSTEMD_LOADKEY(8)

NAME top

       pam_systemd_loadkey - Read password from kernel keyring and set
       it as PAM authtok

SYNOPSIS top

       pam_systemd_loadkey.so

DESCRIPTION top

       pam_systemd_loadkey reads a NUL-separated password list from the
       kernel keyring, and sets the last password in the list as the PAM
       authtok.

       The password list is supposed to be stored in the "user" keyring
       of the root user, by an earlier call to systemd-ask-password(1)
       with --keyname=. You can pass the keyname to pam_systemd_loadkey
       via the keyname= option.

OPTIONS top

       The following options are understood:

       keyname=
           Takes a string argument which sets the keyname to read. The
           default is "cryptsetup". During boot,
           systemd-cryptsetup@.service(8) stores a passphrase or PIN in
           the keyring. The LUKS2 volume key can also be used, via the
           link-volume-key option in crypttab(5).

           Table 1.  Possible values for keyname.
           ┌────────────┬────────────────────────┐
           │ Value      │ Description            │
           ├────────────┼────────────────────────┤
           │ cryptsetup │ Passphrase or recovery │
           │            │ key                    │
           ├────────────┼────────────────────────┤
           │ fido2-pin  │ Security token PIN     │
           ├────────────┼────────────────────────┤
           │ luks2-pin  │ LUKS2 token PIN        │
           ├────────────┼────────────────────────┤
           │ tpm2-pin   │ TPM2 PIN               │
           └────────────┴────────────────────────┘

           Added in version 255.

       debug
           The module will log debugging information as it operates.

           Added in version 255.

EXAMPLE top

       This module is intended to be used when you use LUKS with a
       passphrase, enable autologin in the display manager, and want to
       unlock Gnome Keyring / KDE KWallet automatically. So in total,
       you only enter one password during boot.

       You need to set the password of your Gnome Keyring/KWallet to the
       same as your LUKS passphrase. Then add the following lines to
       your display manager's PAM config under /etc/pam.d/ (e.g.
       sddm-autologin):

           -auth       optional    pam_systemd_loadkey.so
           -auth       optional    pam_gnome_keyring.so
           -session    optional    pam_gnome_keyring.so auto_start
           -session    optional    pam_kwallet5.so auto_start

       And add the following lines to your display manager's systemd
       service file, so it can access root's keyring:

           [Service]
           KeyringMode=inherit

       In this setup, early during the boot process,
       systemd-cryptsetup@.service(8) will ask for the passphrase and
       store it in the kernel keyring with the keyname "cryptsetup".
       Then when the display manager does the autologin,
       pam_systemd_loadkey will read the passphrase from the kernel
       keyring, set it as the PAM authtok, and then pam_gnome_keyring
       and pam_kwallet5 will unlock with the same passphrase.

COLOPHON top

       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 2024-06-14.  (At that
       time, the date of the most recent commit that was found in the
       repository was 2024-06-13.)  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 257~devel                                 PAM_SYSTEMD_LOADKEY(8)

Pages that refer to this page: systemd.directives(7), systemd.index(7)