20.6. System Access Control
Presto separates the concept of the principal who authenticates to the
coordinator from the username that is responsible for running queries. When
running the Presto CLI, for example, the Presto username can be specified using
the --user option.
By default, the Presto coordinator allows any principal to run queries as any Presto user. In a secure environment, this is probably not desirable behavior and likely requires customization.
Implementation
SystemAccessControlFactory is responsible for creating a
SystemAccessControl instance. It also defines a SystemAccessControl
name which is used by the administrator in a Presto configuration.
SystemAccessControl implementations have several responsibilities:
- Verifying whether or not a given principal is authorized to execute queries as a specific user.
- Determining whether or not a given user can alter values for a given system property.
- Performing access checks across all catalogs. These access checks happen before
any connector specific checks and thus can deny permissions that would otherwise
be allowed by
ConnectorAccessControl.
The implementation of SystemAccessControl and SystemAccessControlFactory
must be wrapped as a plugin and installed on the Presto cluster.
Configuration
After a plugin that implements SystemAccessControl and
SystemAccessControlFactory has been installed on the coordinator, it is
configured using an etc/access-control.properties file. All of the properties
other than access-control.name are specific to the SystemAccessControl
implementation.
The access-control.name property is used by Presto to find a registered
SystemAccessControlFactory based on the name returned by
SystemAccessControlFactory.getName(). The remaining properties are passed
as a map to SystemAccessControlFactory.create().
Example configuration file:
access-control.name=custom-access-control
custom-property1=custom-value1
custom-property2=custom-value2