LDAP authentication

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

To enable LDAP authentication for Trino, LDAP-related configuration changes are made on the Trino coordinator.

Using TLS and a configured shared secret is required for LDAP authentication.

Trino server configuration

Trino coordinator node configuration

Access to the Trino coordinator should be through HTTPS, configured as described on TLS and HTTPS.

You also need to make changes to the Trino 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/trino/keystore.jks
http-server.https.keystore.key=keystore_password

Find detailed description for the available properties in HTTP server properties and the following table:

Property	Description
http-server.authentication.password.user-mapping.pattern	Regex to match against user. If matched, user is replaced with first regex group. If not matched, authentication is denied. Defaults to (.*).
http-server.authentication.password.user-mapping.file	File containing rules for mapping user. See User mapping for more information.

Password authenticator configuration

Password authentication must 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.ssl.truststore.path=/path/to/ldap_server.pem
ldap.user-bind-pattern=<Refer below for usage>

Property	Description
ldap.url	The URL to the LDAP server. The URL scheme must be ldap:// or ldaps://. Connecting to the LDAP server without TLS enabled requires ldap.allow-insecure=true.
ldap.allow-insecure	Allow using an LDAP connection that is not secured with TLS.
ldap.ssl.keystore.path	The path to the PEM or JKS keystore file.
ldap.ssl.keystore.password	Password for the key store.
ldap.ssl.truststore.path	The path to the PEM or JKS truststore file.
ldap.ssl.truststore.password	Password for the truststore.
ldap.user-bind-pattern	This property can be used to specify the LDAP user bind string for password authentication. This property must contain the pattern ${USER}, which is replaced by the actual username during the password authentication. The property can contain multiple patterns separated by a colon. Each pattern is checked in order until a login succeeds or all logins fail. Example: ${USER}@corp.example.com:${USER}@corp.example.co.uk
ldap.ignore-referrals	Ignore referrals to other LDAP servers while performing search queries. Defaults to false.
ldap.cache-ttl	LDAP cache duration. Defaults to 1h.
ldap.timeout.connect	Timeout for establishing an LDAP connection. Defaults to 1m.
ldap.timeout.read	Timeout for reading data from an LDAP connection. Defaults to 1m.

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 Trino 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.

Property	Description
ldap.user-base-dn	The base LDAP distinguished name for the user who tries to connect to the server. Example: OU=America,DC=corp,DC=example,DC=com
ldap.group-auth-pattern	This property is used to specify the LDAP query for the LDAP group membership authorization. This query is executed against the LDAP server and if successful, the user is authorized. This property must contain a pattern ${USER}, which is replaced by the actual username in the group authorization search query. See details in the examples section.

Authorization using Trino LDAP service user

Trino server can use dedicated LDAP service user for doing user group membership queries. In such case Trino first issues a group membership query for a Trino user that needs to be authenticated. A user distinguished name is extracted from a group membership query result. Trino then validates user password by creating LDAP context with user distinguished name and user password. In order to use this mechanism ldap.bind-dn, ldap.bind-password and ldap.group-auth-pattern properties need to be defined.

Property	Description
ldap.bind-dn	Bind distinguished name used by Trino when issuing group membership queries. Example: CN=admin,OU=CITY_OU,OU=STATE_OU,DC=domain
ldap.bind-password	Bind password used by Trino when issuing group membership queries. Example: password1234
ldap.group-auth-pattern	This property is used to specify the LDAP query for the LDAP group membership authorization. This query is executed against the LDAP server during login to check if the user belongs to the specified group. If successful, a user distinguished name is extracted from the query result. Trino then validates the user and password by creating an LDAP context with the user's distinguished name and password. This property must contain a pattern ${USER}, which is replaced by the actual username in the group authorization search query. See details in the examples section.

LDAP group authorization examples

With Active Directory, the following syntax can be used:

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))

With OpenLDAP, the following syntax can be used:

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 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}))

Trino CLI

Environment configuration

TLS configuration

When using LDAP authentication, access to the Trino coordinator must be through TLS/HTTPS.

Trino CLI execution

In addition to the options that are required when connecting to a Trino 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

./trino \
--server https://trino-coordinator.example.com:8443 \
--keystore-path /tmp/trino.jks \
--keystore-password password \
--truststore-path /tmp/trino_truststore.jks \
--truststore-password password \
--catalog <catalog> \
--schema <schema> \
--user <LDAP user> \
--password

Find details on the options used in Command line interface and Command line interface.

Troubleshooting

Java keystore file verification

Verify the password for a keystore file and view its contents using JKS files.

Debug Trino to LDAP server issues

If you need to debug issues with Trino communicating with the LDAP server, you can change the log level for the LDAP authenticator:

io.trino.plugin.password=DEBUG

TLS debugging for Trino CLI

If you encounter any TLS related errors when running the Trino CLI, you can run the CLI using the -Djavax.net.debug=ssl parameter for debugging. Use the Trino CLI executable JAR to enable this. For example:

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

Common TLS/SSL errors

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

This error is seen when the Trino coordinator’s certificate is invalid, and does not have the IP you provide in the --server argument of the CLI. You have to regenerate the coordinator's TLS 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.

Authentication or TLS errors with JDK upgrade

Starting with the JDK 8u181 release, to improve the robustness of LDAPS (secure LDAP over TLS) connections, endpoint identification algorithms were enabled by default. See release notes from Oracle. The same LDAP server certificate on the Trino coordinator, running on JDK version >= 8u181, that was previously able to successfully connect to an LDAPS server, may now fail with the following error:

javax.naming.CommunicationException: simple bind failed: ldapserver:636
[Root exception is javax.net.ssl.SSLHandshakeException: java.security.cert.CertificateException: No subject alternative DNS name matching ldapserver found.]

If you want to temporarily disable endpoint identification, you can add the property -Dcom.sun.jndi.ldap.object.disableEndpointIdentification=true to Trino's jvm.config file. However, in a production environment, we suggest fixing the issue by regenerating the LDAP server certificate so that the certificate SAN or certificate subject name matches the LDAP server.