9.6. Built-in System Access Control

A system access control plugin enforces authorization at a global level, before any connector level authorization. You can either use one of the built-in plugins in Presto or provide your own by following the guidelines in System Access Control. Presto offers three built-in plugins:

Plugin Name	Description
allow-all (default value)	All operations are permitted.
read-only	Operations that read data or metadata are permitted, but none of the operations that write data or metadata are allowed. See Read Only System Access Control for details.
file	Authorization checks are enforced using a config file specified by the configuration property security.config-file. See File Based System Access Control for details.

Allow All System Access Control

All operations are permitted under this plugin. This plugin is enabled by default.

Read Only System Access Control

Under this plugin, you are allowed to execute any operation that reads data or metadata, such as SELECT or SHOW. Setting system level or catalog level session properties is also permitted. However, any operation that writes data or metadata, such as CREATE, INSERT or DELETE, is prohibited. To use this plugin, add an etc/access-control.properties file with the following contents:

access-control.name=read-only

File Based System Access Control

This plugin allows you to specify access control rules in a file. To use this plugin, add an etc/access-control.properties file containing two required properties: access-control.name, which must be equal to file, and security.config-file, which must be equal to the location of the config file. For example, if a config file named rules.json resides in etc, add an etc/access-control.properties with the following contents:

access-control.name=file
security.config-file=etc/rules.json

The config file consists of access control rules in JSON format. The rules are matched in the order specified in the file. All regular expressions default to .* if not specified.

This plugin currently supports catalog access control rules and a Kerberos principal rule. If you want to limit access on a system level in any other way, you must implement a custom SystemAccessControl plugin (see System Access Control).

Catalog Rules

This list of rules governs the catalogs particular users can access. The user is granted access to a catalog based on the first matching rule. If no rule matches, access is denied. Each rule is composed of the following fields:

• user (optional): regex to match against user name.
• catalog (optional): regex to match against catalog name.
• allowed (required): boolean indicating whether a user has access to the catalog.

Note

By default, all users have access to the system catalog. You can override this behavior by adding a rule.

Kerberos Principal Rule

This optional rule governs whether a given Kerberos principal can be used to set a given user. Thus, it is possible to ensure that principal bob@REALM is only used by user bob. The rule is composed of a single field:

• exactMatch (required): boolean indicating whether the user must exactly match the Kerberos principal with @REALM trimmed off.

Note

If a principal has a host field specified (e.g. presto/localhost@REALM), the Presto user must be presto/localhost if exactMatch is true

Note

If no kerberosPrincipals rule is specified, exactMatch defaults to false.

For example, if you want to allow only the user admin to access the mysql and the system catalog, allow all users to access the hive catalog, and deny all other access, you can use the following rules:

{
  "catalogs": [
    {
      "user": "admin",
      "catalog": "(mysql|system)",
      "allow": true
    },
    {
      "user": ".*",
      "catalog": "hive",
      "allow": true
    },
    {
      "user": ".*",
      "catalog": "system",
      "allow": false
    }
  ],
  "kerberosPrincipals":
   {
      "exactMatch": "true"
   }
}