Using LDAP authentication plugins¶

LDAP (Lightweight Directory Access Protocol) provides an alternative method to access existing directory servers, which maintain information about individuals, groups, and organizations.

Percona Server for MySQL supports the simple LDAP authentication. The Percona simple LDAP authentication plugin is a free and Open Source implementation of the MySQL Enterprise Simple LDAP authentication plugin. Percona Server for MySQL also supports an SASL-based LDAP authentication plugin. This plugin only supports the SCRAM-SHA-1 SASL mechanism.

Plugin names and file names¶

The following tables show the plugin names and the file name for simple LDAP authentication and SASL-based LDAP authentication.

Simple LDAP authentication plugin names and library nameSASL-based LDAP authentication plugin names and library names

Plugin or file	Plugin name or file name
Server-side plugin	authentication_ldap_simple
client-side plugin	mysql_clear_password
library file	authentication_ldap_simple.so

Plugin or file	Plugin name or file name
Server-side plugin	authentication_ldap_sasl
client-side plugin	authentication_ldap_sasl_client
library files	authentication_ldap_sasl.so authentication_ldap_sasl_client.so

How does the authentication work¶

The server-side LDAP plugins work only with the specific client-side plugin:

The authentication_ldap_simple plugin, on the server, performs the simple LDAP authentication. The client, using mysql_clear_password, connects to the server. The client plugin sends the password to the server as cleartext. For this method, use a secure connection between the client and server.
The authentication_ldap_sasl plugin, on the server, performs the SASL-based LDAP authentication. The client must use the authentication_ldap_sasl_client plugin. The method does not send the password to the server in cleartext. The server-side and client-side plugins use Simple Authentication and Security Layer (SASL) to send secure messages within the LDAP protocol.

For either method, the database server rejects the connection if the client user name and the host name do not match a server account.

If a database server LDAP authentication is successful, the LDAP server searches for an entry. The LDAP server matches the user and authenticates using the LDAP password. If the database server account names the LDAP user distinguished name (DN), added by the IDENTIFIED WITH <plugin-name> BY '<auth-string>' clause, the LDAP server uses that value and the LDAP password provided by the client. This method fails if the DN and password have incorrect values

If the LDAP server finds multiple matches or no match, authentication fails.

If the password is correct, and the LDAP server finds a match, then LDAP authentication succeeds. The LDAP server returns the LDAP entry and the authentication plugin determines the authenticated user’s name based on the entry. If the LDAP entry has no group attribute, the plugin returns the client user name as the authenticated name. If the LDAP entry has a group attribute, the plugin returns the group value as the authenticated name.

The database server compares the client user name to the authenticated user name. If these names are the same, the database server uses the client user name to check for privileges. If the name differs, then the database server looks for an account that matches the authenticated name.

Prerequisites for authentication¶

The LDAP authentication plugins required the following:

An available LDAP server
The LDAP server must contain the LDAP user accounts to be authenticated
The OpenLDAP client library must be available on the same system as the plugin

The SASL-based LDAP authentication additionally requires the following:

Configure the LDAP server to communicate with a SASL server
Available SASL client library on the same system as the client plugin.
Services are configured to use the supported SCRAM-SHA-1 SASL mechanism

Install the plugins¶

You can use either of the following methods to install the plugins.

Load the plugins at server start¶

Use either of the following methods to load the plugin at server start.

Load the simple LDAP authenticationLoad the SASL_based LDAP authentication plugin

Add the following statements to your my.cnf file to load simple LDAP authentication:

[mysqld]
plugin-load-add=authentication_ldap_simple.so
authentication_ldap_simple_server_host=127.0.0.1
authentication_ldap_simple_bind_base_dn='dc=percona, dc=com'

Restart the server for the changes to take effect.

Add the following statements to your my.cnf file to load the SASL-based LDAP authentication:

[mysqld]
plugin-load-add=authentication_ldap_sasl.so
authentication_ldap_sasl_server_host=127.0.0.1
authentication_ldap_sasl_bind_base_dn='dc=percona, dc=com'

Load the plugins at runtime¶

Install the plugin with the following statements.

Load the simple LDAP authentication pluginLoad the SASL-based LDAP authentication plugin

mysql> INSTALL PLUGIN authentication_ldap_simple SONAME 'authentication_ldap_simple.so';

To set and persist values at runtime, use the following statements:

mysql> SET PERSIST authentication_ldap_simple_server_host='127.0.0.1';
mysql> SET PERSIST authentication_ldap_simple_bind_base_dn='dc=percona, dc=com';

mysql> INSTALL PLUGIN authentication_ldap_sasl SONAME 'authentication_ldap_sasl.so';

To set and persist values at runtime, use the following statements:

mysql> SET PERSIST authentication_ldap_sasl_server_host='127.0.0.1';
mysql> SET PERSIST authentication_ldap_sasl_bind_base_dn='dc=percona, dc=com';

Create a user using simple LDAP authentication¶

There are several methods to add or modify a user.

Use authentication_ldap_simple pluginUse the authentication string in simple LDAP

In the CREATE USER statement or the ALTER USER statement, for simple LDAP authentication, you can specify the authentication_ldap_simple plugin in the IDENTIFIED WITH clause:

mysql> CREATE USER ... IDENTIFIED WITH authentication_ldap_simple;

Using the IDENTIFIED WITH clause, the database server assigns the specified plugin.

If you provide the optional authentication string clause, ‘cn,ou,dc,dc’ in the example, the string is stored along with the password.

mysql> CREATE USER ... IDENTIFIED WITH authentication_ldap_simple BY 'cn=[user name],ou=[organization unit],dc=[domain component],dc=com'

Unless the authentication_ldap_simple_group_role_mapping variable is used, creating a user with an authentication string does not use the following system variables:

Creating the user with IDENTIFIED BY authentication_ldap_simple uses the variables.

Creating the user with the authentication_ldap_simple_group_role_mapping variable also adds the authentication_ldap_simple_bind_root_dn and authentication_ldap_simple_bind_root_pwd variables.

Create a user using SASL-based LDAP authentication¶

There are several methods to add or modify a user.

Use authentication_ldap_sasl pluginUse the authentication string in SASL-based LDAP

For SASL-based LDAP authentication, in the CREATE USER statement or the ALTER USER statement, you can specify the authentication_ldap_sasl plugin:

mysql> CREATE USER ... IDENTIFIED WITH authentication_ldap_sasl;

If you provide the optional authentication string clause, ‘cn,ou,dc,dc’ in the example, the string is stored along with the password.

mysql> CREATE USER ... IDENTIFIED WITH authentication_ldap_sasl BY 'cn=[user name],ou=[organization unit],dc=[domain component],dc=com'

Unless the authentication_ldap_sasl_group_role_mapping variable is used, creating a user with an authentication string does not use the following system variables:

Creating the user with IDENTIFIED BY authentication_ldap_sasl uses the variables.

Creating the user with the authentication_ldap_sasl_group_role_mapping variable also adds theauthentication_ldap_sasl_bind_root_dn and authentication_ldap_sasl_bind_root_pwd variables.

Examples¶

The following sections are examples of using simple LDAP authentication and SASL-based LDAP authentication.

For the purposes of this example, we use the following LDAP user:

uid=ldapuser,ou=testusers,dc=percona,dc=com

Simple LDAP authenticationSASL-based LDAP authentication

The following example configures an LDAP user and connects to the database server.

Create a database server account for ldapuser with the following statement:

mysql> CREATE USER 'ldapuser'@'localhost' IDENTIFIED WITH authentication_ldap_simple BY 'uid=ldapuser,ou=testusers,dc=percona,dc=com';

The authentication string does not include the LDAP password. This password must be provided by the client user when they connect.

mysql> mysql --user=ldapuser --password --enable-cleartext-plugin

The user enters the ldapuser password. The client sends the password as cleartext, which is necessary when using a server-side LDAP library without SASL. The following actions may minimize the risk:

Require that the database server clients explicitly enable the mysql_clear_password plugin with --enable-cleartext-plugin.
Require that the database server clients connect to the database server using an encrypted connection

The following example configures an LDAP user and connect to the database server.

Create a database server account for ldapuser with the following statement:

mysql> CREATE USER 'ldapuser'@'localhost' IDENTIFIED WITH authentication_ldap_sasl AS 'uid=ldapuser,ou=testusers,dc=percona,dc=com';

The authentication string does not include the LDAP password. This password must be provided by the client user when they connect.

Clients connect ot the database server by providing the database server user name and LDAP password:

mysql> mysql --user=ldapuser --password

The authentication is similar to the authentication method used by simple LDAP authentication, except that the client and the database server SASL LDAP plugins use SASL messages. These messages are secure within the LDAP protocol.

Uninstall the plugins¶

If you installed either plugin at server startup, remove those options from the my.cnf file, remove any startup options that set LDAP system variables, and restart the server.

Uninstall the simple LDAP authentication pluginUninstall the SASL-based LDAP authentication plugin

If you installed the plugins at runtime, run the following statements:

mysql> UNINSTALL PLUGIN authentication_ldap_simple;

If you used SET_PERSIST, use RESET PERSIST to remove the settings.

If you installed the plugins at runtime, run the following statements:

mysql> UNINSTALL PLUGIN authentication_ldap_sasl;

If you used SET_PERSIST, use RESET PERSIST to remove the settings.

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Last update: 2024-08-14