3.3. LDAP Authentication

Presto can be configured to enable frontend LDAP authentication over HTTPS for clients, such as the Presto CLI, or the JDBC and ODBC drivers. At present only simple LDAP authentication mechanism involving username and password is supported. The Presto client sends a username and password to the coordinator and coordinator validates these credentials using an external LDAP service.

To enable LDAP authentication for Presto, configuration changes are made on the Presto coordinator. No changes are required to the worker configuration; only the communication from the clients to the coordinator is authenticated. However, if you want to secure the communication between Presto nodes with SSL/TLS configure Secure Internal Communication.

Presto Server Configuration

Environment Configuration

Secure LDAP

Presto requires Secure LDAP (LDAPS), so make sure you have TLS enabled on your LDAP server.

TLS Configuration on Presto Coordinator

You need to import the LDAP server’s TLS certificate to the default Java truststore of the Presto coordinator to secure TLS connection. You can use the following example keytool command to import the certificate ldap_server.crt, to the truststore on the coordinator.

$ keytool -import -keystore <JAVA_HOME>/jre/lib/security/cacerts -trustcacerts -alias ldap_server -file ldap_server.crt

In addition to this, access to the Presto coordinator should be through HTTPS. You can do it by creating a Java Keystore File for TLS on the coordinator.

Presto Coordinator Node Configuration

You must make the following changes to the environment prior to configuring the Presto coordinator to use LDAP authentication and HTTPS.

• Secure LDAP
• Java Keystore File for TLS

You also need to make changes to the Presto configuration files. LDAP authentication is configured on the coordinator in two parts. The first part is to enable HTTPS support and password authentication in the coordinator’s config.properties file. The second part is to configure LDAP as the password authenticator plugin.

Server Config Properties

The following is an example of the required properties that need to be added to the coordinator’s config.properties file:

http-server.authentication.type=PASSWORD
http-server.https.enabled=true
http-server.https.port=8443
http-server.https.keystore.path=/etc/presto_keystore.jks
http-server.https.keystore.key=keystore_password

Password Authenticator Configuration

Password authentication needs to be configured to use LDAP. Create an etc/password-authenticator.properties file on the coordinator. Example:

password-authenticator.name=ldap
ldap.url=ldaps://ldap-server:636
ldap.user-bind-pattern=<Refer below for usage>

Based on the LDAP server implementation type, the property ldap.user-bind-pattern can be used as described below.

Active Directory

ldap.user-bind-pattern=${USER}@<domain_name_of_the_server>

Example:

ldap.user-bind-pattern=${USER}@corp.example.com

OpenLDAP

ldap.user-bind-pattern=uid=${USER},<distinguished_name_of_the_user>

Example:

ldap.user-bind-pattern=uid=${USER},OU=America,DC=corp,DC=example,DC=com

Authorization based on LDAP Group Membership

You can further restrict the set of users allowed to connect to the Presto coordinator based on their group membership by setting the optional ldap.group-auth-pattern and ldap.user-base-dn properties in addition to the basic LDAP authentication properties.

Based on the LDAP server implementation type, the property ldap.group-auth-pattern can be used as described below.

Active Directory

ldap.group-auth-pattern=(&(objectClass=<objectclass_of_user>)(sAMAccountName=${USER})(memberof=<dn_of_the_authorized_group>))

Example:

ldap.group-auth-pattern=(&(objectClass=person)(sAMAccountName=${USER})(memberof=CN=AuthorizedGroup,OU=Asia,DC=corp,DC=example,DC=com))

OpenLDAP

ldap.group-auth-pattern=(&(objectClass=<objectclass_of_user>)(uid=${USER})(memberof=<dn_of_the_authorized_group>))

Example:

ldap.group-auth-pattern=(&(objectClass=inetOrgPerson)(uid=${USER})(memberof=CN=AuthorizedGroup,OU=Asia,DC=corp,DC=example,DC=com))

For OpenLDAP, for this query to work, make sure you enable the memberOf overlay.

You can also use this property for scenarios where you want to authorize a user based on complex group authorization search queries. For example, if you want to authorize a user belonging to any one of multiple groups (in OpenLDAP), this property may be set as follows:

ldap.group-auth-pattern=(&(|(memberOf=CN=normal_group,DC=corp,DC=com)(memberOf=CN=another_group,DC=com))(objectClass=inetOrgPerson)(uid=${USER}))

Presto CLI

Environment Configuration

TLS Configuration

Access to the Presto coordinator should be through HTTPS when using LDAP authentication. The Presto CLI can use either a Java Keystore file or Java Truststore for its TLS configuration.

If you are using keystore file, it can be copied to the client machine and used for its TLS configuration. If you are using truststore, you can either use default java truststores or create a custom truststore on the CLI. We do not recommend using self-signed certificates in production.

Presto CLI Execution

In addition to the options that are required when connecting to a Presto coordinator that does not require LDAP authentication, invoking the CLI with LDAP support enabled requires a number of additional command line options. You can either use --keystore-* or --truststore-* properties to secure TLS connection. The simplest way to invoke the CLI is with a wrapper script.

#!/bin/bash
./presto \
--server https://presto-coordinator.example.com:8443 \
--keystore-path /tmp/presto.jks \
--keystore-password password \
--truststore-path /tmp/presto_truststore.jks \
--truststore-password password \
--catalog <catalog> \
--schema <schema> \
--user <LDAP user> \
--password

Troubleshooting

Java Keystore File Verification

Verify the password for a keystore file and view its contents using Java Keystore File Verification.

SSL Debugging for Presto CLI

If you encounter any SSL related errors when running Presto CLI, you can run CLI using -Djavax.net.debug=ssl parameter for debugging. You should use the Presto CLI executable jar to enable this. Eg:

java -Djavax.net.debug=ssl \
-jar \
presto-cli-<version>-executable.jar \
--server https://coordinator:8443 \
<other_cli_arguments>

Common SSL errors

java.security.cert.CertificateException: No subject alternative names present

This error is seen when the Presto coordinator’s certificate is invalid and does not have the IP you provide in the --server argument of the CLI. You will have to regenerate the coordinator’s SSL certificate with the appropriate SAN added.

Adding a SAN to this certificate is required in cases where https:// uses IP address in the URL rather than the domain contained in the coordinator’s certificate, and the certificate does not contain the SAN parameter with the matching IP address as an alternative attribute.