PAM_LISTFILE(8) Linux-PAM Manual PAM_LISTFILE(8)NAMEpam_listfile - deny or allow services based on an arbitrary file
SYNOPSIS
pam_listfile.so item=[tty|user|rhost|ruser|group|shell]
sense=[allow|deny] file=/path/filename
onerr=[succeed|fail] [apply=[user|@group]]
DESCRIPTIONpam_listfile is a PAM module which provides a way to deny or allow
services based on an arbitrary file.
The module gets the item of the type specified -- user specifies the
username, PAM_USER; tty specifies the name of the terminal over which
the request has been made, PAM_TTY; rhost specifies the name of the
remote host (if any) from which the request was made, PAM_RHOST; and
ruser specifies the name of the remote user (if available) who made the
request, PAM_RUSER -- and looks for an instance of that item in the
file=filename. filename contains one line per item listed. If the item
is found, then if sense=allow, PAM_SUCCESS is returned, causing the
authorization request to succeed; else if sense=deny, PAM_AUTH_ERR is
returned, causing the authorization request to fail.
If an error is encountered (for instance, if filename does not exist,
or a poorly-constructed argument is encountered), then if
onerr=succeed, PAM_SUCCESS is returned, otherwise if onerr=fail,
PAM_AUTH_ERR or PAM_SERVICE_ERR (as appropriate) will be returned.
An additional argument, apply=, can be used to restrict the application
of the above to a specific user (apply=username) or a given group
(apply=@groupname). This added restriction is only meaningful when used
with the tty, rhost and shell items.
Besides this last one, all arguments should be specified; do not count
on any default behavior.
No credentials are awarded by this module.
OPTIONS
item=[tty|user|rhost|ruser|group|shell]
What is listed in the file and should be checked for.
sense=[allow|deny]
Action to take if found in file, if the item is NOT found in the
file, then the opposite action is requested.
file=/path/filename
File containing one item per line. The file needs to be a plain file
and not world writeable.
onerr=[succeed|fail]
What to do if something weird happens like being unable to open the
file.
apply=[user|@group]
Restrict the user class for which the restriction apply. Note that
with item=[user|ruser|group] this oes not make sense, but for
item=[tty|rhost|shell] it have a meaning.
MODULE SERVICES PROVIDED
The services auth, account, password and session are supported.
RETURN VALUES
PAM_AUTH_ERR
Authentication failure.
PAM_BUF_ERR
Memory buffer error.
PAM_IGNORE
The rule does not apply to the apply option.
PAM_SERVICE_ERR
Error in service module.
PAM_SUCCESS
Success.
EXAMPLES
Classic 'ftpusers' authentication can be implemented with this entry in
/etc/pam.d/ftpd:
#
# deny ftp-access to users listed in the /etc/ftpusers file
#
auth required pam_listfile.so \
onerr=succeed item=user sense=deny file=/etc/ftpusers
Note, users listed in /etc/ftpusers file are (counterintuitively) not
allowed access to the ftp service.
To allow login access only for certain users, you can use a
/etc/pam.d/login entry like this:
#
# permit login to users listed in /etc/loginusers
#
auth required pam_listfile.so \
onerr=fail item=user sense=allow file=/etc/loginusers
For this example to work, all users who are allowed to use the login
service should be listed in the file /etc/loginusers. Unless you are
explicitly trying to lock out root, make sure that when you do this,
you leave a way for root to log in, either by listing root in
/etc/loginusers, or by listing a user who is able to su to the root
account.
SEE ALSOpam.conf(5), pam.d(8), pam(8)AUTHORpam_listfile was written by Michael K. Johnson <johnsonm@redhat.com>
and Elliot Lee <sopwith@cuc.edu>.
Linux-PAM Manual 06/22/2006 PAM_LISTFILE(8)