October 11th, 2010 by Leandro Morgado
In the last post, we saw how to create a test OpenLDAP server, populate it and secure it with SSL certificates. Now we are going to have a look at how to configure MySQL Enterprise Manager (MEM) to authenticate against LDAP. We will be examining a few different kinds of setup methods.
1. Using LDAP to fetch just the user password
The simplest form is to configure a user with MEM and set it to the LDAP type. The user’s role is setup in MEM during user creation time and is not fetched from LDAP. Below you can see the user definition page:
The username is user1 as specified in MEM, but where do we get the password from? We need to tell MEM how to find this user. Here is a sample user as defined by the LDIF file used in my previous post:
# user1, People, example.com dn: uid=user1,ou=People,dc=example,dc=com objectClass: person objectClass: inetOrgPerson objectClass: organizationalPerson objectClass: top cn: Aaren Atp sn: Atp description: This is the description for Aaren Atp. employeeNumber: 1 givenName: Aaren homePhone: +1 280 375 4325 initials: ALA l: New Haven mail: email@example.com mobile: +1 680 734 6300 ou: admin pager: +1 850 883 8888 postalAddress: Aaren Atp$70110 Fourth Street$New Haven, OH 93694 postalCode: 936942 st: OH street: 70110 Fourth Street telephoneNumber: +1 390 103 6917 uid: user1 userPassword:: e1NTSEF9Z0tsZjU4cm50Wit4b045N0U4cWlldVJQK1RMOVAzTGw=
Now tell MEM to look for the uid by navigating to Settings > Global Settings > LDAP Authentication:
The password is specified in the userPassword attribute and uses standard LDAP supported formats. Technically what MEM does is an LDAP simple bind operation (Authentication Mode = Bind as User) with the given username/password and then attempts to search for the given user using the DN pattern. If the binding and search succeeds, we assume the password is correct. With this in place, you can now login with user1 without having to specify the password in MEM.
2. Adding MEM Roles from LDAP
If we want to fetch the user’s role from LDAP in addition to the password, we need to enable the Map LDAP Roles to Application Roles check box in the LDAP settings page. We’ll see the two ways of doing this shortly.
The good thing about enabling role mapping is that manual user creation in the Web dashboard is no longer required. If the user does not already exist within MEM, it will be “copied” from LDAP to MEM when that user first logs in. The lookup order is Built-in users first, then LDAP users. If you want user authentication to be exclusively done against LDAP then make LDAP authoritative by ticking the check box:
WARNING: Enabling this prevents Built-in users from being authenticated. Make sure that you test with non authoritative authentication first and make sure role mapping is working. Also, ensure that you have a valid LDAP user who has admin privileges or risk locking yourself out.
Below is an example of how my test user table looked before logging in with user1:
And this is how it looks after a successful login:
Notice how the LDAP user1 entry was created automatically in the MEM user table with values from the LDAP directory.
2.2.1 MEM roles in a LDAP user’s attribute
The first way of achieving role mapping is to simply have an attribute in the user’s entry, whose attribute value will be the role. In our example, we use the ou attribute. The relevant attributes for our sample users are:
uid: user1 ou: admin .... uid: user2 ou: dba
The relevant settings in MEM are:
Now when you login with user2 for example, its role will be fetched from LDAP. We can verify this in the User Preferences section as shown by the screenshot below:
If we try user1, then we will get an admin (manager) role.
Note that some versions have a bug that prevents this setup from working. Check if you are affected.
2.2.2 MEM roles specified by a LDAP group
There is another way to specify a user’s role. Instead of each user having an attribute representing the role, a roles group is created, which enumerates the users that are members of that role. In our example, this is represented in the LDIF file as:
dn: ou=groups,dc=example,dc=com objectClass: organizationalUnit ou: groups dn: cn=admin,ou=groups,dc=example,dc=com objectClass: groupOfUniqueNames cn: admin uniqueMember: uid=user1,ou=People,dc=example,dc=com dn: cn=dba,ou=groups,dc=example,dc=com objectClass: groupOfUniqueNames cn: dba uniqueMember: uid=user2,ou=People,dc=example,dc=com
So again, we need to tell MEM how to do role lookups from the LDAP directory. This is how the LDAP settings in MEM would look like for our particular case:
Note, that due this bug, you might not get this particular setup to work.
2.3 Configuring LDAP lookups to use SSL and STARTTLS
Once plain text authentication is working, you can choose to secure communications between MEM and the LDAP server with either STARTTLS or SSL. Obviously the LDAP server must support it. Note that SSL (ldaps) is deprecated in the latest LDAP v3 and STARTTLS is prefered. MEM supports both types. To use STARTTLS, simply select it in the menu as follows:
There is no need to change the default port. Using SSL (ldaps) however, implies using the ldaps port, which by default is 636, and setting MEM to use SSL(ldaps) :
One thing to note is that the (Primary) Server Hostname should match the SSL certificate of the LDAP server.
If you are using self signed certificates that were not issued by a commercial SSL company, MEM will not have the root CA (Certificate Authority) in it’s repository. You should see a message in the $INSTALL_DIR/monitor/apache-tomcat/logs/catalina.out logfile:
javax.net.ssl.SSLHandshakeException: sun.security.validator.ValidatorException: PKIX path building failed: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target
To fix this, you will need to import the your root CA certificate that was used to generate the LDAP server’s certificate. This can be achieve with the Java Keytool utility as follows:
shell> cd /opt/mysql/enterprise/monitor/java
shell> bin/keytool -import -trustcacerts -alias ldapssl \ -file /etc/openldap/ssl/ca-cert.pem -keystore lib/security/cacerts
This needs to be run under MEM’s Java installation directory. Unless you have previously modified it, the default password is changeit . We saw how to create a CA certificate (ca-cert.pem) in the previous post. Finally, restart the MEM monitor service.
In case you have problems importing your root CA certificate, make sure it is correctly format and acceptable by the Java keytool utility:
“keytool can import X.509 v1, v2, and v3 certificates, and PKCS#7 formatted certificate chains consisting of certificates of that type. The data to be imported must be provided either in binary encoding format, or in printable encoding format (also known as Base64 encoding) as defined by the Internet RFC 1421 standard. In the latter case, the encoding must be bounded at the beginning by a string that starts with ‘—–BEGIN’, and bounded at the end by a string that starts with ‘—–END’.”
To troubleshoot, the best place is to look at the catalina.out logfile. If you need extra debugging information, you can start MEM’s JVM as follows:
In the current version (126.96.36.1991) this should be added at around line 180 of $INSTALL_DIR/monitor/apache-tomcat/bin/catalina.sh. Note that catalina.sh will get overwritten when you next upgrade so if you want JAVA_OPTS changes to be persistent, then use setenv.sh (or setenv.bat for Windows.). A Tomcat restart is needed. Note that a lot of information is logged and you’re log files will grow rather quickly. Please remember to turn this off in regular production mode.
Hopefully this will help when configuring MEM to authenticate it’s users against a LDAP directory.