PAM_ALREADYLOGGEDIN(8) | System Manager's Manual | PAM_ALREADYLOGGEDIN(8) |
NAME¶
pam_alreadyloggedin
—
Already-logged-in PAM module
SYNOPSIS¶
[service-name] module-type control-flag pam_alreadyloggedin [options]DESCRIPTION¶
The Already-logged-in authentication service module for PAM,pam_alreadyloggedin
provides functionality for only
one PAM category: authentication. In terms of the
module-type parameter, this is the
“auth
” feature. It also provides null
functions for other PAM categories.
Already-logged-in Authentication Module¶
The Already-logged-in authentication component (pam_sm_authenticate
()), returns success if and only
if the target user's ID is identical to a current login specified in the
utmp(5) database and verified with matching permissions on
that login's respective terminal in /dev. If a user
shows up in w(8) output, they will generally be allowed to
authenticate using this method.
The following options may be passed to the authentication module:
debug
- Enable verbose output to syslog at LOG_DEBUG level.
no_debug
- Disable verbose output to syslog even it's enabled at compile time.
no_root
- 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 ttyglob*. The ttyglob*
argument is specified as a shell glob, and checked using the
fnmatch(3) function. For example,
restrict_tty=/dev/tty[1-6]
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 ttyglob*.
EXAMPLE¶
Modifyauth
section of the
/etc/pam.d/login file like following:
auth required /lib/security/pam_securetty.so auth sufficient /lib/security/pam_alreadyloggedin.so no_root auth required /lib/security/pam_stack.so service=system-auth
BUGS¶
FreeBSD version expects /dev/ prefix inrestrict_tty
value, but value of
restrict_loggedin_tty
should be without them. Linux
version expects /dev/ in both cases.
SEE ALSO¶
fnmatch(3), getuid(2), stat(2), utmp(5), w(8), pam.conf(5), pam(8)AUTHORS¶
Adopted for Linux PAM by Ilya Evseev at Jan 2004.The original pam_alreadyloggedin
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 (“CBOSS”), as
part of the DARPA CHATS research program.
January 30, 2004 | Linux-PAM |