pam_listfile(8) — Linux manual page
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(8)
AUTHOR
pam_listfile was written by Michael K. Johnson
<johnsonm@redhat.com> and Elliot Lee <sopwith@cuc.edu>.
COLOPHON
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 project's upstream Git repository
⟨https://github.com/linux-pam/linux-pam.git⟩ on 2023-12-22. (At
that time, the date of the most recent commit that was found in
the repository was 2023-12-18.) If you discover any rendering
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