man pam_nologin (8): Prevent non-root users from login

SYNOPSIS

pam_nologin.so [file=/path/nologin] [successok]

DESCRIPTION

pam_nologin is a PAM module that prevents users from logging into the system when /var/run/nologin or /etc/nologin exists. The contents of the file are displayed to the user. The pam_nologin module has no effect on the root user's ability to log in.

OPTIONS

file=/path/nologin

: Use this file instead the default /var/run/nologin or /etc/nologin.

successok

: Return PAM_SUCCESS if no file exists, the default is PAM_IGNORE.

MODULE TYPES PROVIDED

The auth and acct module types are provided.

RETURN VALUES

PAM_AUTH_ERR

: The user is not root and /etc/nologin exists, so the user is not permitted to log in.

PAM_BUF_ERR

: Memory buffer error.

PAM_IGNORE

: This is the default return value.

PAM_SUCCESS

: Success: either the user is root or the nologin file does not exist.

PAM_USER_UNKNOWN

: User not known to the underlying authentication module.

EXAMPLES

The suggested usage for /etc/pam.d/login is:

auth  required  pam_nologin.so

NOTES

In order to make this module effective, all login methods should be secured by it. It should be used as a required method listed before any sufficient methods in order to get standard Unix nologin semantics. Note, the use of successok module argument causes the module to return PAM_SUCCESS and as such would break such a configuration - failing sufficient modules would lead to a successful login because the nologin module succeeded.

AUTHOR

pam_nologin was written by Michael K. Johnson <[email protected]>.