system-auth - Common configuration file for PAMified services
The purpose of these configuration files are to provide a common interface for all applications and service daemons calling into the PAM library.
The system-auth configuration file is included from nearly all individual service configuration files with the help of the substack directive.
The password-auth fingerprint-auth smartcard-auth configuration files are for applications which handle authentication from different types of devices via simultaneously running individual conversations instead of one aggregate conversation.
The three Linux-PAM Guides, for system administrators, module developers, and application developers.