pam_xauth - forward xauth keys between users
SYNOPSIS
session optional /lib/security/pam_xauth.so arguments
DESCRIPTION
pam_xauth.so is designed to forward xauth keys (sometimes
referred to as "cookies") between users.
Without pam_xauth, when xauth is enabled and a user uses
the su command to assume another user's priviledges, that
user is no longer able to access the original user's X
display because the new user does not have the key needed
to access the display. pam_xauth solves the problem by
forwarding the key from the user running su (the source
user) to the user whose identity the source user is assum
ing (the target user) when the session is created, and
destroying the key when the session is torn down.
This means, for example, that when you run su from an
xterm sesssion, you will be able to run X programs without
explicitly dealing with the xauth command or ~/.Xauthority
files.
pam_xauth will only forward keys if xauth can list a key
connected to the $DISPLAY environment variable.
ARGUMENTS
debug Turns on debugging messages sent to syslog.
xauthpath=/usr/X11R6/bin/xauth
Specify the path the xauth program (the default is
/usr/X11R6/bin/xauth).
IMPLEMENTATION DETAILS
pam_xauth will work only if it is used from a setuid
application in which the getuid() call returns the id of
the user running the application, and for which PAM can
supply the name of the account that the user is attempting
to assume. The typical application of this type is su.
The application must call both pam_open_session() and
pam_close_session() with the ruid set to the uid of the
calling user and the euid set to root, and must have pro
vided as the PAM_USER item the name of the target user.
pam_xauth calls xauth as the source user to extract the
key for $DISPLAY, then calls xauth as the target user to
merge the key into the a temporary database and later
remove the database.
pam_xauth cannot be told not to remove the keys when the
session is closed.
/usr/share/doc/pam*/html/index.html
BUGS
Let's hope not, but if you find any, please report them
via the "Bug Track" link at http://bugzilla.red
hat.com/bugzilla/
AUTHOR
Nalin Dahyabhai <nalin@redhat.com>, based on original ver
sion by Michael K. Johnson <johnsonm@redhat.com>
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