Hive connector security configuration

Authorization

You can enable authorization checks for the hive by setting the hive.security property in the Hive catalog properties file. This property must be one of the following values:

Property Value	Description
legacy (default value)	Few authorization checks are enforced, thus allowing most operations. The config properties hive.allow-drop-table,hive.allow-rename-table,hive.allow-add-column, hive.allow-drop-columnand hive.allow-rename-column are used.
read-only	Operations that read data or metadata, such asSELECT, are permitted, but none of the operations that write data or metadata, such as CREATE, INSERTor DELETE, are allowed.
file	Authorization checks are enforced using a catalog-level access control configuration file whose path is specified in thesecurity.config-file catalog configuration property. Seecatalog-file-based-access-control for details.
sql-standard	Users are permitted to perform the operations as long as they have the required privileges as per the SQL standard. In this mode, Trino enforces the authorization checks for queries based on the privileges defined in Hive metastore. To alter these privileges, use the/sql/grant and /sql/revoke commands. Seehive-sql-standard-based-authorization for details.
allow-all	No authorization checks are enforced.

SQL standard based authorization

When sql-standard security is enabled, Trino enforces the same SQL standard based authorization as Hive does.

Since Trino's ROLE syntax support matches the SQL standard, and Hive does not exactly follow the SQL standard, there are the following limitations and differences:

• CREATE ROLE role WITH ADMIN is not supported.
• The admin role must be enabled to execute CREATE ROLE, DROP ROLE or CREATE SCHEMA.
• GRANT role TO user GRANTED BY someone is not supported.
• REVOKE role FROM user GRANTED BY someone is not supported.
• By default, all a user's roles, except admin, are enabled in a new user session.
• One particular role can be selected by executing SET ROLE role.
• SET ROLE ALL enables all of a user's roles except admin.
• The admin role must be enabled explicitly by executing SET ROLE admin.
• GRANT privilege ON SCHEMA schema is not supported. Schema ownership can be changed with ALTER SCHEMA schema SET AUTHORIZATION user

Authentication

The default security configuration of the /connector/hive does not use authentication when connecting to a Hadoop cluster. All queries are executed as the user who runs the Trino process, regardless of which user submits the query.

The Hive connector provides additional security options to support Hadoop clusters that have been configured to use Kerberos <hive-security-kerberos-support>.

When accessing HDFS (Hadoop Distributed File System), Trino can impersonate<hive-security-impersonation> the end user who is running the query. This can be used with HDFS permissions and ACLs (Access Control Lists) to provide additional security for data.

caution

Access to the Trino coordinator should be secured e.g., using Kerberos or password authentication, when using Kerberos authentication to Hadoop services. Failure to secure access to the Trino coordinator could result in unauthorized access to sensitive data on the Hadoop cluster. Refer to /security for further information.

See /security/kerberos for information on setting up Kerberos authentication.

Kerberos support

In order to use the Hive connector with a Hadoop cluster that uses kerberos authentication, you need to configure the connector to work with two services on the Hadoop cluster:

• The Hive metastore Thrift service
• The Hadoop Distributed File System (HDFS)

Access to these services by the Hive connector is configured in the properties file that contains the general Hive connector configuration.

note

If your krb5.conf location is different from /etc/krb5.conf you must set it explicitly using the java.security.krb5.conf JVM property in jvm.config file.

Example: -Djava.security.krb5.conf=/example/path/krb5.conf.

Hive metastore Thrift service authentication

In a Kerberized Hadoop cluster, Trino connects to the Hive metastore Thrift service using SASL (Simple Authentication and Security Layer) and authenticates using Kerberos. Kerberos authentication for the metastore is configured in the connector's properties file using the following properties:

Property Name	Description
hive.metastore.authentication.type	Hive metastore authentication type.
hive.metastore.thrift.impersonation.enabled	Enable Hive metastore end user impersonation.
hive.metastore.service.principal	The Kerberos principal of the Hive metastore service.
hive.metastore.client.principal	The Kerberos principal that Trino uses when connecting to the Hive metastore service.
hive.metastore.client.keytab	Hive metastore client keytab location.

hive.metastore.authentication.type

One of NONE or KERBEROS. When using the default value of NONE, Kerberos authentication is disabled, and no other properties need to be configured.

When set to KERBEROS the Hive connector connects to the Hive metastore Thrift service using SASL and authenticate using Kerberos.

This property is optional; the default is NONE.

hive.metastore.thrift.impersonation.enabled

Enable end-user Hive metastore impersonation.

This property is optional; the default is false. See hive-security-metastore-impersonation for more information.

hive.metastore.service.principal

The Kerberos principal of the Hive metastore service. The Trino coordinator uses this to authenticate the Hive metastore.

The _HOST placeholder can be used in this property value. When connecting to the Hive metastore, the Hive connector substitutes in the hostname of the metastore server it is connecting to. This is useful if the metastore runs on multiple hosts.

Example: hive/hive-server-host@EXAMPLE.COM or hive/_HOST@EXAMPLE.COM.

This property is optional; no default value.

hive.metastore.client.principal

The Kerberos principal that Trino uses when connecting to the Hive metastore.

The _HOST placeholder can be used in this property value. When connecting to the Hive metastore, the Hive connector substitutes in the hostname of the worker node Trino is running on. This is useful if each worker node has its own Kerberos principal.

Example: trino/trino-server-node@EXAMPLE.COM or trino/_HOST@EXAMPLE.COM.

This property is optional; no default value.

caution

Unless hive-security-metastore-impersonation is enabled, the principal specified by hive.metastore.client.principal must have sufficient privileges to remove files and directories within the hive/warehouse directory. If the principal does not, only the metadata is removed, and the data continues to consume disk space.

This occurs because the Hive metastore is responsible for deleting the internal table data. When the metastore is configured to use Kerberos authentication, all of the HDFS operations performed by the metastore are impersonated. Errors deleting data are silently ignored.

hive.metastore.client.keytab

The path to the keytab file that contains a key for the principal specified by hive.metastore.client.principal. This file must be readable by the operating system user running Trino.

This property is optional; no default value.

Example configuration with NONE authentication

hive.metastore.authentication.type=NONE

The default authentication type for the Hive metastore is NONE. When the authentication type is NONE, Trino connects to an unsecured Hive metastore. Kerberos is not used.

Example configuration with KERBEROS authentication

hive.metastore.authentication.type=KERBEROS
hive.metastore.thrift.impersonation.enabled=true
hive.metastore.service.principal=hive/hive-metastore-host.example.com@EXAMPLE.COM
hive.metastore.client.principal=trino@EXAMPLE.COM
hive.metastore.client.keytab=/etc/trino/hive.keytab

When the authentication type for the Hive metastore Thrift service is KERBEROS, Trino connects as the Kerberos principal specified by the property hive.metastore.client.principal. Trino authenticates this principal using the keytab specified by the hive.metastore.client.keytab property, and verifies that the identity of the metastore matches hive.metastore.service.principal.

Keytab files must be distributed to every node in the cluster that runs Trino.

Additional Information About Keytab Files.<hive-security-additional-keytab>

HDFS authentication

In a Kerberized Hadoop cluster, Trino authenticates to HDFS using Kerberos. Kerberos authentication for HDFS is configured in the connector's properties file using the following properties:

Property Name	Description
hive.hdfs.authentication.type	HDFS authentication type. Possible values are NONEor KERBEROS.
hive.hdfs.impersonation.enabled	Enable HDFS end-user impersonation.
hive.hdfs.trino.principal	The Kerberos principal that Trino uses when connecting to HDFS.
hive.hdfs.trino.keytab	HDFS client keytab location.
hive.hdfs.wire-encryption.enabled	Enable HDFS wire encryption.

hive.hdfs.authentication.type

One of NONE or KERBEROS. When using the default value of NONE, Kerberos authentication is disabled, and no other properties need to be configured.

When set to KERBEROS, the Hive connector authenticates to HDFS using Kerberos.

This property is optional; the default is NONE.

hive.hdfs.impersonation.enabled

Enable end-user HDFS impersonation.

The section End User Impersonation<hive-security-impersonation> gives an in-depth explanation of HDFS impersonation.

This property is optional; the default is false.

hive.hdfs.trino.principal

The Kerberos principal Trino uses when connecting to HDFS.

The _HOST placeholder can be used in this property value. When connecting to HDFS, the Hive connector substitutes in the hostname of the worker node Trino is running on. This is useful if each worker node has its own Kerberos principal.

Example: trino-hdfs-superuser/trino-server-node@EXAMPLE.COM or trino-hdfs-superuser/_HOST@EXAMPLE.COM.

This property is optional; no default value.

hive.hdfs.trino.keytab

The path to the keytab file that contains a key for the principal specified by hive.hdfs.trino.principal. This file must be readable by the operating system user running Trino.

This property is optional; no default value.

hive.hdfs.wire-encryption.enabled

In a Kerberized Hadoop cluster that uses HDFS wire encryption, this should be set to true to enable Trino to access HDFS. Note that using wire encryption may impact query execution performance.

Example configuration with NONE authentication

hive.hdfs.authentication.type=NONE

The default authentication type for HDFS is NONE. When the authentication type is NONE, Trino connects to HDFS using Hadoop's simple authentication mechanism. Kerberos is not used.

Example configuration with KERBEROS authentication

hive.hdfs.authentication.type=KERBEROS
hive.hdfs.trino.principal=hdfs@EXAMPLE.COM
hive.hdfs.trino.keytab=/etc/trino/hdfs.keytab

When the authentication type is KERBEROS, Trino accesses HDFS as the principal specified by the hive.hdfs.trino.principal property. Trino authenticates this principal using the keytab specified by the hive.hdfs.trino.keytab keytab.

Keytab files must be distributed to every node in the cluster that runs Trino.

Additional Information About Keytab Files.<hive-security-additional-keytab>

End user impersonation

Impersonation accessing HDFS

Trino can impersonate the end user who is running a query. In the case of a user running a query from the command line interface, the end user is the username associated with the Trino CLI process or argument to the optional --user option. Impersonating the end user can provide additional security when accessing HDFS if HDFS permissions or ACLs are used.

HDFS Permissions and ACLs are explained in the HDFS Permissions Guide.

NONE authentication with HDFS impersonation

hive.hdfs.authentication.type=NONE
hive.hdfs.impersonation.enabled=true

When using NONE authentication with impersonation, Trino impersonates the user who is running the query when accessing HDFS. The user Trino is running as must be allowed to impersonate this user, as discussed in the section configuring-hadoop-impersonation. Kerberos is not used.

KERBEROS authentication with HDFS impersonation

hive.hdfs.authentication.type=KERBEROS
hive.hdfs.impersonation.enabled=true
hive.hdfs.trino.principal=trino@EXAMPLE.COM
hive.hdfs.trino.keytab=/etc/trino/hdfs.keytab

When using KERBEROS authentication with impersonation, Trino impersonates the user who is running the query when accessing HDFS. The principal specified by the hive.hdfs.trino.principal property must be allowed to impersonate the current Trino user, as discussed in the section configuring-hadoop-impersonation. Trino authenticates hive.hdfs.trino.principal using the keytab specified by hive.hdfs.trino.keytab.

Keytab files must be distributed to every node in the cluster that runs Trino.

Additional Information About Keytab Files.<hive-security-additional-keytab>

Impersonation accessing the Hive metastore

Trino supports impersonating the end user when accessing the Hive metastore. Metastore impersonation can be enabled with

hive.metastore.thrift.impersonation.enabled=true

When using KERBEROS Metastore authentication with impersonation, the principal specified by the hive.metastore.client.principal property must be allowed to impersonate the current Trino user, as discussed in the section configuring-hadoop-impersonation.

Impersonation in Hadoop

In order to use impersonation, the Hadoop cluster must be configured to allow the user or principal that Trino is running as to impersonate the users who log in to Trino. Impersonation in Hadoop is configured in the file core-site.xml. A complete description of the configuration options can be found in the Hadoop documentation.

Additional information about Keytab files

Keytab files contain encryption keys that are used to authenticate principals to the Kerberos KDC (Key Distribution Center). These encryption keys must be stored securely; you need to take the same precautions to protect them that you take to protect ssh private keys.

In particular, access to keytab files should be limited to the accounts that actually need to use them to authenticate. In practice, this is the user that the Trino process runs as. The ownership and permissions on keytab files need to be set to prevent other users from reading or modifying the files.

Keytab files need to be distributed to every node running Trino. Under common deployment situations, the Hive connector configuration is the same on all nodes. This means that the keytab needs to be in the same location on every node.

You should ensure that the keytab files have the correct permissions on every node after distributing them.