Access Levels Explained¶
In the role-based access control model supported by the Okera Platform, roles are granted access to resources by means of access levels. The Okera Policy Engine supports the following access levels:
Attribute-based access control (ABAC) policies only support
SELECT privilege level. Read more here.
|Access levels||Available Scopes||Description|
||Database, Table, Attribute Namespace||Ability to either assign attributes on the specified data object, or to assign attributes from the specified attribute namespace.|
||Catalog, Database, Table, URI, Crawler, Attribute Namespace, Role||Full and unrestricted access to any data object and any descendants. This permission is a superset of all the privileges below. Adding the
||Catalog, Database, Table||Ability to edit metadata for specified object, such as alter the table/view definition, add/drop/rename columns, change datatypes, partitions, storage locations, table properties. Note: If applied at
||Catalog, Database, Attribute Namespace||Ability to create an object within another object, for instance,
||Catalog, Database||Ability to create an object (database, table or view) and automatically receive ALL privileges on the object you created e.g.
||Catalog||Ability to create crawlers. Users will automatically be granted ownership (
||Catalog||Ability to create connections. Users will automatically be granted ownership (
||Catalog||Ability to create roles. Users will automatically be granted ownership (
||Catalog, Database, URI||Ability to delete the data of an object.|
||Catalog, Database, Table, Attribute Namespace, Role||Ability to remove specified objects.|
||Database, Table, Column||Write access to the object. Does not include read access.|
||Catalog, Role||Ability to add or remove groups granted to a specified
||Catalog, Role||Ability to grant permissions to the specified role. You will only be able to grant permissions on objects you have WITH GRANT OPTION on.|
||Database, Table||Ability to remove attributes on the specified data object. Must be combined with
||Catalog, Database, Table, Column||Read access to an object and any descendants.|
||Catalog, Database, Table||Read access to object metadata only. Cannot be granted at a column level.|
||Catalog, Database, Table||Replace rows of data in the specified data object and to all data objects within it. Does not include read access.|
||Catalog, Dataconnection||Ability to register data from the specified
||Catalog, Database, Table||Ability to see audit data only for the specified objects. The user also needs read access to the
||Catalog, Database, Table||Read access to an object's full metadata. The user will be able to see all metadata that an admin would see on this object.|
||Catalog, Database, Table||Ability to grant permissions on the specified data to roles. The user will only be able to grant to roles they have the ability to
Object Types and Scope¶
All permissions are usually scoped at a specific object level.
Here are the object types supported by Okera:
||Global scope for all objects in the Catalog.|
||Scope on a single database and all included objects|
||Permissions for a specific table or view, with all its columns|
||As before, but for a subset of columns only|
||Specific to a file-based resource.|
||Scope on a single crawler and all unregistered datasets inside it.|
||Refers to a specific namespace of attributes (i.e. tags)|
||Scope on a single role.|
* If you see the term
SERVER, it refers to the old syntax for
Scope is the selection of an object at some point in the hierarchy, and knowing that all child objects are included. For example, if you allow read access to a specific database for a certain role, all user groups that are associated with that role will be able to read all datasets (that is, all tables and views) in the database.
Note: You cannot revoke permissions on a scope that were granted on a higher scope. If you grant access for a database to a specific role, you cannot revoke access to some of the datasets included in that database.
Assigning permissions for child objects are commonly issued at the next higher scope. For instance, you need to permit create permissions for a role on the database level, allowing the role owners to create new tables and views inside that database.
Views are handled using the same scope as tables. In other words, when addressing views as part of the authorization commands, refer to the table documentation.
URIs are a special kind of object, registering paths or specific resource files (such as Java JARs) that are accessible for non-administrative users. There are a handful types of actions that require file system permissions:
- Creating databases
- Creating external tables
- Creating functions
- Altering an external table's location
- Altering a table's set of partitions
In general, any action that requires the
ROW FORMAT SERDE keywords is checked for file system permissions before it is allowed by the platform.
Some of the above operations are only allowed at the catalog level scope, implicitly making anyone allowed at that level a global administrator.
And since global administrators are unrestricted, it is assumed they have unrestricted access to the underlying file systems.
Note: The file system checks for global administrators fall back to the Okera Data Access Service (ODAS) having access to the file resources. In practice, every ODAS setup will run with an authenticated technical user account, which needs to have access to all resources that are referenced by any of the location dependent SQL statements.
The following table shows each affected action with the scope and privilege they require, and what that means for the file system checks:
|Action Type||Scope||Privilege||File System Check|
|Create Database||Catalog||All||Not needed|
|Create Function||Catalog||All||Not needed|
|Create External Table||Database||All||Yes1|
|Alter External Table Location||Database||All||Yes1|
|Alter Table Partitions||Database||All||Yes1|
Legend: 1 Applies to non-administrative users only
Note: URIs only are supported in combination with the All privilege, as shown in the table.
For non-specific URIs, that is those which are not referencing a specific resource file (see Extending ODAS for an example), access is checked for the given file system path. Any file or directory inside that location is automatically included. That allows, for example, an administrator to permit access to a specific root path for a given role. Any user that is associated with that role is allowed the same level of access inside that root path.
Finally, any SQL statement that uses one of those resources implicitly, like a
SELECT statement using a UDF, does not require a file system permission check again.
This makes sense as first a table or function must be created before it can be used.
In other words, an administrator or elevated user (with "All" privileges on the catalog or database level respectively) creates the object or function using the explicit location URI.
Any other user with, for example, a read-only role is allowed to access the object or function without requiring explicit access to the underlying resources.
Here are examples showing the difference:
Example: SQL statements that require explicit access to the specified resources
CREATE EXTERNAL TABLE transactions_schemaed( txnid BIGINT, dt_time STRING, sku STRING, userid INT, price FLOAT, creditcard STRING, ip STRING) ROW FORMAT DELIMITED FIELDS TERMINATED BY ',' LOCATION 's3://acme-sales-data/transactions'; ALTER TABLE sales.transactions_schemaed RECOVER PARTITIONS; CREATE FUNCTION sales.mask(STRING) RETURNS STRING LOCATION 's3://acme-udfs-public/udfs/mask-udf.jar' SYMBOL='com.acme.hiveudf.MaskUDF';
Example: SQL statements that do not require explicit access to the underlying resources
SELECT count(txnid) FROM sales.transactions_schemaed; CREATE VIEW sales.transactions AS SELECT txnid, dt_time, sku FROM sales.transactions_schemaed;
How this is used in practice is explained in Best Practices.