pam_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
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.
What is listed in the file and should be checked for.
Action to take if found in file, if the item is NOT found in
the file, then the opposite action is requested.
File containing one item per line. The file needs to be a
plain file and not world writable.
What to do if something weird happens like being unable to
open the file.
Restrict the user class for which the restriction apply. Note
that with item=[user|ruser|group] this does not make sense,
but for item=[tty|rhost|shell] it have a meaning.
Do not treat service refusals or missing list files as errors
that need to be logged.
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.
This page is part of the linux-pam (Pluggable Authentication
Modules for Linux) project. Information about the project can be
found at ⟨http://www.linux-pam.org/⟩. If you have a bug report
for this manual page, see ⟨//www.linux-pam.org/⟩. This page was
obtained from the tarball Linux-PAM-1.3.0.tar.bz2 fetched from
⟨http://www.linux-pam.org/library/⟩ on 2021-08-27. If you
discover any rendering problems in this HTML version of the page,
or you believe there is a better or more up-to-date source for
the page, or you have corrections or improvements to the
information in this COLOPHON (which is not part of the original
manual page), send a mail to firstname.lastname@example.org
Linux-PAM Manual 04/01/2016 PAM_LISTFILE(8)