6.4.1.8 No-Login Pluggable Authentication

This section describes how to install the no-login authentication plugin. For general information about installing plugins, see Section 5.6.1, “Installing and Uninstalling Plugins”.

To be usable by the server, the plugin library file must be located in the MySQL plugin directory (the directory named by the plugin_dir system variable). If necessary, configure the plugin directory location by setting the value of plugin_dir at server startup.

The plugin library file base name is mysql_no_login. The file name suffix differs per platform (for example, .so for Unix and Unix-like systems, .dll for Windows).

To load the plugin at server startup, use the --plugin-load-add option to name the library file that contains it. With this plugin-loading method, the option must be given each time the server starts. For example, put these lines in the server my.cnf file (adjust the .so suffix for your platform as necessary):

[mysqld]
plugin-load-add=mysql_no_login.so

After modifying my.cnf, restart the server to cause the new settings to take effect.

Alternatively, to register the plugin at runtime, use this statement (adjust the .so suffix as necessary):

INSTALL PLUGIN loads the plugin immediately, and also registers it in the mysql.plugins system table to cause the server to load it for each subsequent normal startup.

To verify plugin installation, examine the INFORMATION_SCHEMA.PLUGINS table or use the SHOW PLUGINS statement (see Section 5.6.2, “Obtaining Server Plugin Information”). For example:

If the plugin fails to initialize, check the server error log for diagnostic messages.

To associate MySQL accounts with the no-login plugin, see Using No-Login Pluggable Authentication.

The method used to uninstall the no-login authentication plugin depends on how you installed it:

This section describes how to use the no-login authentication plugin to prevent connections from MySQL client programs to the server. It is assumed that the server is running with the server-side plugin enabled, as described in Installing No-Login Pluggable Authentication.

To refer to the no-login authentication plugin in the IDENTIFIED WITH clause of a CREATE USER statement, use the name mysql_no_login.

An account that authenticates using mysql_no_login may be used as the DEFINER for stored program and view objects. If such an object definition also includes SQL SECURITY DEFINER, it executes with that account's privileges. DBAs can use this behavior to provide access to confidential or sensitive data that is exposed only through well-controlled interfaces.

The following example provides a simple illustration of these principles. It defines an account that does not permit client connections, and associates with it a view that exposes only certain columns of the mysql.user system table:

To provide protected access to the view to an ordinary user, do this:

Now the ordinary user can use the view to access the limited information it presents:

Attempts by the user to access columns other than those exposed by the view result in an error, as do all attempts to select from the view by users not granted access to it.

An account that authenticates using mysql_no_login may be used as a proxied base user for proxy accounts:

This enables clients to access MySQL through the proxy account (real_user) but not to bypass the proxy mechanism by connecting directly as the proxied user (proxy_base).