Authorization

SAS Federation Server authorizations apply to all administration DDL. That is, most administration DDL is performed by an administrator only (defined as a user who has the ADMINISTER privilege on SAS Federation Server), but some commands, such as CREATE CACHE, have specific privileges which can be assigned to users and groups.

In the case where a user is connected to data sources providing customer data, SAS Federation Server authorizations are applied over the underlying data source. SQL statements submitted to the server are first parsed and then evaluated against the privileges defined in SAS Federation Server. If the action is not permitted from SAS Federation Server, an error is returned to the user, and no SQL is sent to the underlying data source. If the action is permitted, the SQL statement is evaluated, and the FedSQL processor determines what SQL should be sent to the underlying data sources. In summary, if the underlying data source does not permit the SQL action, then an error is returned. Otherwise, the SQL action is performed and results sent back to the user.

SAS Federation Server authorizations are also very powerful when used in conjunction with shared logins. Shared logins allow many users to be mapped to the same single login for an underlying data source. This allows for easy back-end data source user management, since each user of SAS Federation Server does not require an individual login. However, this alone would mean that all users of that shared login would have the same privileges to the accessible data. However, SAS Federation Server authorization can be used to restrict individual access to data, no matter what the shared login is allowed to access in the underlying data source.

As with other system metadata, the SAS Federation Server authorization process uses an internal database to store security definitions for users, groups and objects. Privileges can be set on individual users, or on groups, which affect all members of the group. By default, no users (except those defined as system users) are granted any specific privileges on any objects in SAS Federation Server, and the lack of any privilege anywhere results in a DENY from the server’s authorization subsystem. The administrator must specifically grant privileges before a user can perform any actions through SAS Federation Server.

When security definitions are stored in SAS Federation Server, they are stored as entered in the GRANT or DENY SQL syntax. Using the following statement as an example:

GRANT SELECT ON TABLE “MyTable” TO BOB

SAS Federation Server creates a system table object for table "MyTable". When performing privilege comparisons at run time (for example, when the user Bob issues a SELECT statement against table “MyTable”), the server will perform case sensitive or insensitive comparisons, depending on the data source. Case sensitivity from the data source is registered during the CREATE DATA SERVICE DDL statement, and the system automatically determines the correct setting. However, the administrator can specify case sensitivity as well via the CASE_SENSITIVITY option in the CREATE DATA SERVICE DDL. It is highly recommended that the server default to the correct value. Specifying an incorrect value for case sensitivity can result in incorrect privilege determination.

Case sensitivity settings only apply to relations and columns. Data services, catalogs, schemas and DSNs are always treated in a case-insensitive manner. Also, user and group identifiers are treated as case insensitive.