The Already-logged-in authentication service module for PAM,
provides functionality for only one PAM category:
In terms of the
parameter, this is the
It also provides null functions for other PAM categories.
Already-logged-in Authentication Module
The Already-logged-in authentication component
returns success if and only if the target user's ID is identical to a current login specified in the
database and verified with matching permissions on that login's respective terminal in
If a user shows up in
output, they will generally be allowed to authenticate using this method.
The following options may be passed to the authentication module:
Enable verbose output to syslog at LOG_DEBUG level.
Disable verbose output to syslog even it's enabled at compile time.
Never allow login with a target user ID of zero.
restrict_tty = ttyglob*
Only allow login if the terminal device currently being authenticated on matches
argument is specified as a shell glob, and checked using the
function. For example,
allows logging from text consoles of physical terminal only.
restrict_loggedin_tty = ttyglob*
Disallow recognition that the user is already logged in unless the terminal device logged in upon matches
section of the
file like following:
Adopted for Linux PAM by Ilya Evseev at Jan 2004.
Lp The original
module and this manual page were developed for the FreeBSD Project by
NAI Labs and ThinkSec AS, the Security Research Division of Network
Associates, Inc. under DARPA/SPAWAR contract N66001-01-C-8035
as part of the DARPA CHATS research program.