PAM_LISTFILE(8)           (06/08/2020)            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

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              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

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          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>.

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