Section (3) pam_setcred
pam_setcred function is
used to establish, maintain and delete the credentials of a
user. It should be called to set the credentials after a user
has been authenticated and before a session is opened for the
user (with pam_open_session(3)). The
credentials should be deleted after the session has been
closed (with pam_close_session(3)).
A credential is something that the user possesses. It is some property, such as a Kerberos ticket, or a supplementary group membership that make up the uniqueness of a given user. On a Linux system the user_zsingle_quotesz_s UID and GID_zsingle_quotesz_s are credentials too. However, it has been decided that these properties (along with the default supplementary groups of which the user is a member) are credentials that should be set directly by the application and not by PAM. Such credentials should be established, by the application, prior to a call to this function. For example, initgroups(2) (or equivalent) should have been performed.
Valid flags, any
one of which, may be logically OR_zsingle_quotesz_d with
Initialize the credentials for the user.
Delete the user_zsingle_quotesz_s credentials.
Fully reinitialize the user_zsingle_quotesz_s credentials.
Extend the lifetime of the existing credentials.
Memory buffer error.
Failed to set user credentials.
User credentials are expired.
Failed to retrieve user credentials.
Data was successful stored.
A NULL pointer was submitted as PAM handle, the function was called by a module or another system error occured.
User is not known to an authentication module.