pam_listfile

PAM_LISTFILE(8)                Linux-PAM Manual                PAM_LISTFILE(8)

NAME
       pam_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]] [quiet]

DESCRIPTION
       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 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 writable.

       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 does not make sense, but for
           item=[tty|rhost|shell] it have a meaning.

       quiet
           Do not treat service refusals or missing list files as errors that
           need to be logged.

MODULE TYPES PROVIDED
       All module types (auth, account, password and session) are provided.

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 ALSO
       pam.conf(5), pam.d(5), pam(7)

AUTHOR
       pam_listfile was written by Michael K. Johnson <johnsonm@redhat.com>
       and Elliot Lee <sopwith@cuc.edu>.

Linux-PAM Manual                  05/18/2017                   PAM_LISTFILE(8)