pam_keyinit.so [debug] [force] [revoke]
The module checks to see if the process's session keyring is the user-session-keyring(7), and, if it is, creates a new session-keyring(7) with which to replace it. If a new session keyring is created, it will install a link to the user-keyring(7) in the session keyring so that keys common to the user will be automatically accessible through it. The session keyring of the invoking process will thenceforth be inherited by all its children unless they override it.
In order to allow other PAM modules to attach tokens to the keyring, this module provides both an auth (limited to pam_setcred(3) and a session component. The session keyring is created in the module called. Moreover this module should be included as early as possible in a PAM configuration.
This module is intended primarily for use by login processes. Be aware that after the session keyring has been replaced, the old session keyring and the keys it contains will no longer be accessible.
This module should not, generally, be invoked by programs like su, since it is usually desirable for the key set to percolate through to the alternate context. The keys have their own permissions system to manage this.
The keyutils package is used to manipulate keys more directly. This can be obtained from:
session required pam_keyinit.so
This will prevent keys from one session leaking into another session for the same user.