role_name ::= identifier | string= Security

Database Roles

CQL uses database roles to represent users and group of users. Syntactically, a role is defined by:

role_name ::= identifier | string

CREATE ROLE

Creating a role uses the CREATE ROLE statement:

create_role_statement ::= CREATE ROLE [ IF NOT EXISTS ] role_name
                          [ WITH role_options# ]
role_options ::= role_option ( AND role_option)*
role_option ::= PASSWORD '=' string
                | HASHED PASSWORD '=' string
                | LOGIN '=' boolean
                | SUPERUSER '=' boolean
                | OPTIONS '=' map_literal
                | ACCESS TO DATACENTERS set_literal
                | ACCESS TO ALL DATACENTERS

For instance:

CREATE ROLE new_role;
CREATE ROLE alice WITH PASSWORD = 'password_a' AND LOGIN = true;
CREATE ROLE alice WITH HASHED PASSWORD = '$2a$10$JSJEMFm6GeaW9XxT5JIheuEtPvat6i7uKbnTcxX3c1wshIIsGyUtG' AND LOGIN = true;
CREATE ROLE bob WITH PASSWORD = 'password_b' AND LOGIN = true AND SUPERUSER = true;
CREATE ROLE carlos WITH OPTIONS = { 'custom_option1' : 'option1_value', 'custom_option2' : 99 };
CREATE ROLE alice WITH PASSWORD = 'password_a' AND LOGIN = true AND ACCESS TO DATACENTERS {'DC1', 'DC3'};
CREATE ROLE alice WITH PASSWORD = 'password_a' AND LOGIN = true AND ACCESS TO ALL DATACENTERS;

By default roles do not possess LOGIN privileges or SUPERUSER status.

Permissions on database resources are granted to roles; types of resources include keyspaces, tables, functions and roles themselves. Roles may be granted to other roles to create hierarchical permissions structures; in these hierarchies, permissions and SUPERUSER status are inherited, but the LOGIN privilege is not.

If a role has the LOGIN privilege, clients may identify as that role when connecting. For the duration of that connection, the client will acquire any roles and privileges granted to that role.

Only a client with with the CREATE permission on the database roles resource may issue CREATE ROLE requests (see the relevant section), unless the client is a SUPERUSER. Role management in Cassandra is pluggable and custom implementations may support only a subset of the listed options.

Role names should be quoted if they contain non-alphanumeric characters.

Setting credentials for internal authentication

Use the WITH PASSWORD clause to set a password for internal authentication, enclosing the password in single quotation marks.

If internal authentication has not been set up or the role does not have LOGIN privileges, the WITH PASSWORD clause is not necessary.

USE WITH HASHED PASSWORD to provide the jBcrypt hashed password directly. See the hash_password tool.

Restricting connections to specific datacenters

If a network_authorizer has been configured, you can restrict login roles to specific datacenters with the ACCESS TO DATACENTERS clause followed by a set literal of datacenters the user can access. Not specifiying datacenters implicitly grants access to all datacenters. The clause ACCESS TO ALL DATACENTERS can be used for explicitness, but there’s no functional difference.

Creating a role conditionally

Attempting to create an existing role results in an invalid query condition unless the IF NOT EXISTS option is used. If the option is used and the role exists, the statement is a no-op:

CREATE ROLE other_role;
CREATE ROLE IF NOT EXISTS other_role;

ALTER ROLE

Altering a role options uses the ALTER ROLE statement:

alter_role_statement ::= ALTER ROLE [ IF EXISTS ] role_name WITH role_options

For example:

ALTER ROLE bob WITH PASSWORD = 'PASSWORD_B' AND SUPERUSER = false;
ALTER ROLE bob WITH HASHED PASSWORD = '$2a$10$JSJEMFm6GeaW9XxT5JIheuEtPvat6i7uKbnTcxX3c1wshIIsGyUtG' AND SUPERUSER = false;

If the role does not exist, the statement will return an error, unless IF EXISTS is used in which case the operation is a no-op.

USE WITH HASHED PASSWORD to provide the jBcrypt hashed password directly. See the hash_password tool.

Restricting connections to specific datacenters

If a network_authorizer has been configured, you can restrict login roles to specific datacenters with the ACCESS TO DATACENTERS clause followed by a set literal of datacenters the user can access. To remove any data center restrictions, use the ACCESS TO ALL DATACENTERS clause.

Conditions on executing ALTER ROLE statements:

• a client must have SUPERUSER status to alter the SUPERUSER status of another role

• a client cannot alter the SUPERUSER status of any role it currently holds

• a client can only modify certain properties of the role with which it identified at login (e.g. PASSWORD)

• to modify properties of a role, the client must be granted ALTER permission <cql-permissions> on that role

DROP ROLE

Dropping a role uses the DROP ROLE statement:

drop_role_statement ::= DROP ROLE [ IF EXISTS ] role_name

DROP ROLE requires the client to have DROP permission <cql-permissions> on the role in question. In addition, client may not DROP the role with which it identified at login. Finally, only a client with SUPERUSER status may DROP another SUPERUSER role.

Attempting to drop a role which does not exist results in an invalid query condition unless the IF EXISTS option is used. If the option is used and the role does not exist the statement is a no-op.

GRANT ROLE

Granting a role to another uses the GRANT ROLE statement:

grant_role_statement ::= GRANT role_name TO role_name

For example:

GRANT report_writer TO alice;

This statement grants the report_writer role to alice. Any permissions granted to report_writer are also acquired by alice.

Roles are modelled as a directed acyclic graph, so circular grants are not permitted. The following examples result in error conditions:

GRANT role_a TO role_b;
GRANT role_b TO role_a;
GRANT role_a TO role_b;
GRANT role_b TO role_c;
GRANT role_c TO role_a;

REVOKE ROLE

Revoking a role uses the REVOKE ROLE statement:

revoke_role_statement ::= REVOKE role_name FROM role_name

For example:

REVOKE report_writer FROM alice;

This statement revokes the report_writer role from alice. Any permissions that alice has acquired via the report_writer role are also revoked.

LIST ROLES

All the known roles (in the system or granted to specific role) can be listed using the LIST ROLES statement:

list_roles_statement ::= LIST ROLES [ OF role_name] [ NORECURSIVE ]

For instance:

LIST ROLES;

returns all known roles in the system, this requires DESCRIBE permission on the database roles resource.

This example enumerates all roles granted to alice, including those transitively acquired:

LIST ROLES OF alice;

This example lists all roles directly granted to bob without including any of the transitively acquired ones:

LIST ROLES OF bob NORECURSIVE;

Users

Prior to the introduction of roles in Cassandra 2.2, authentication and authorization were based around the concept of a USER. For backward compatibility, the legacy syntax has been preserved with USER centric statements becoming synonyms for the ROLE based equivalents. In other words, creating/updating a user is just a different syntax for creating/updating a role.

CREATE USER

Creating a user uses the CREATE USER statement:

create_user_statement ::= CREATE USER [ IF NOT EXISTS ] role_name
                          [ WITH [ HASHED ] PASSWORD string ]
                          [ user_option ]
user_option: SUPERUSER | NOSUPERUSER

For example:

CREATE USER alice WITH PASSWORD 'password_a' SUPERUSER;
CREATE USER bob WITH PASSWORD 'password_b' NOSUPERUSER;
CREATE USER bob WITH HASHED PASSWORD '$2a$10$JSJEMFm6GeaW9XxT5JIheuEtPvat6i7uKbnTcxX3c1wshIIsGyUtG' NOSUPERUSER;

The CREATE USER command is equivalent to CREATE ROLE where the LOGIN option is true. So, the following pairs of statements are equivalent:

CREATE USER alice WITH PASSWORD 'password_a' SUPERUSER;
CREATE ROLE alice WITH PASSWORD = 'password_a' AND LOGIN = true AND SUPERUSER = true;
CREATE USER IF NOT EXISTS alice WITH PASSWORD 'password_a' SUPERUSER;
CREATE ROLE IF NOT EXISTS alice WITH PASSWORD = 'password_a' AND LOGIN = true AND SUPERUSER = true;
CREATE USER alice WITH PASSWORD 'password_a' NOSUPERUSER;
CREATE ROLE alice WITH PASSWORD = 'password_a' AND LOGIN = true AND SUPERUSER = false;
CREATE USER alice WITH PASSWORD 'password_a' NOSUPERUSER;
CREATE ROLE alice WITH PASSWORD = 'password_a' AND LOGIN = true;
CREATE USER alice WITH PASSWORD 'password_a';
CREATE ROLE alice WITH PASSWORD = 'password_a' AND LOGIN = true;

ALTER USER

Altering the options of a user uses the ALTER USER statement:

alter_user_statement ::= ALTER USER [ IF EXISTS ] role_name [ WITH [ HASHED ] PASSWORD string] [ user_option]

If the role does not exist, the statement will return an error, unless IF EXISTS is used in which case the operation is a no-op. For example:

ALTER USER alice WITH PASSWORD 'PASSWORD_A';
ALTER USER alice WITH HASHED PASSWORD '$2a$10$JSJEMFm6GeaW9XxT5JIheuEtPvat6i7uKbnTcxX3c1wshIIsGyUtG';
ALTER USER bob SUPERUSER;

DROP USER

Dropping a user uses the DROP USER statement:

drop_user_statement ::= DROP USER [ IF EXISTS ] role_name

LIST USERS

Existing users can be listed using the LIST USERS statement:

list_users_statement::= LIST USERS

Note that this statement is equivalent to LIST ROLES, but only roles with the `LOGIN privilege are included in the output.

Data Control

Permissions

Permissions on resources are granted to roles; there are several different types of resources in Cassandra and each type is modelled hierarchically:

• The hierarchy of Data resources, Keyspaces and Tables has the structure ALL KEYSPACES → KEYSPACE → TABLE.

• Function resources have the structure ALL FUNCTIONS → KEYSPACE → FUNCTION

• Resources representing roles have the structure ALL ROLES → ROLE

• Resources representing JMX ObjectNames, which map to sets of MBeans/MXBeans, have the structure ALL MBEANS → MBEAN

Permissions can be granted at any level of these hierarchies and they flow downwards. So granting a permission on a resource higher up the chain automatically grants that same permission on all resources lower down. For example, granting SELECT on a KEYSPACE automatically grants it on all TABLES in that KEYSPACE. Likewise, granting a permission on ALL FUNCTIONS grants it on every defined function, regardless of which keyspace it is scoped in. It is also possible to grant permissions on all functions scoped to a particular keyspace.

Modifications to permissions are visible to existing client sessions; that is, connections need not be re-established following permissions changes.

The full set of available permissions is:

• CREATE

• ALTER

• DROP

• SELECT

• MODIFY

• AUTHORIZE

• DESCRIBE

• EXECUTE

Not all permissions are applicable to every type of resource. For instance, EXECUTE is only relevant in the context of functions or mbeans; granting EXECUTE on a resource representing a table is nonsensical. Attempting to GRANT a permission on resource to which it cannot be applied results in an error response. The following illustrates which permissions can be granted on which types of resource, and which statements are enabled by that permission.

GRANT PERMISSION

Granting a permission uses the GRANT PERMISSION statement:

grant_permission_statement ::= GRANT permissions ON resource TO role_name
permissions ::= ALL [ PERMISSIONS ] | permission [ PERMISSION ]
permission ::= CREATE | ALTER | DROP | SELECT | MODIFY | AUTHORIZE | DESCRIBE | EXECUTE
resource ::=    ALL KEYSPACES
                | KEYSPACE keyspace_name
                | [ TABLE ] table_name
                | ALL ROLES
                | ROLE role_name
                | ALL FUNCTIONS [ IN KEYSPACE keyspace_name ]
                | FUNCTION function_name '(' [ cql_type( ',' cql_type )* ] ')'
                | ALL MBEANS
                | ( MBEAN | MBEANS ) string

For example:

GRANT SELECT ON ALL KEYSPACES TO data_reader;

This example gives any user with the role data_reader permission to execute SELECT statements on any table across all keyspaces:

GRANT MODIFY ON KEYSPACE keyspace1 TO data_writer;

To give any user with the role data_writer permission to perform UPDATE, INSERT, UPDATE, DELETE and TRUNCATE queries on all tables in the keyspace1 keyspace:

GRANT DROP ON keyspace1.table1 TO schema_owner;

To give any user with the schema_owner role permissions to DROP a specific keyspace1.table1:

GRANT EXECUTE ON FUNCTION keyspace1.user_function( int ) TO report_writer;

This command grants any user with the report_writer role permission to execute SELECT, INSERT and UPDATE queries which use the function keyspace1.user_function( int ):

GRANT DESCRIBE ON ALL ROLES TO role_admin;

This grants any user with the role_admin role permission to view any and all roles in the system with a LIST ROLES statement.

GRANT ALL

When the GRANT ALL form is used, the appropriate set of permissions is determined automatically based on the target resource.

Automatic Granting

When a resource is created, via a CREATE KEYSPACE, CREATE TABLE, CREATE FUNCTION, CREATE AGGREGATE or CREATE ROLE statement, the creator (the role the database user who issues the statement is identified as), is automatically granted all applicable permissions on the new resource.

REVOKE PERMISSION

Revoking a permission from a role uses the REVOKE PERMISSION statement:

revoke_permission_statement ::= REVOKE permissions ON resource FROM role_name

For example:

REVOKE SELECT ON ALL KEYSPACES FROM data_reader;
REVOKE MODIFY ON KEYSPACE keyspace1 FROM data_writer;
REVOKE DROP ON keyspace1.table1 FROM schema_owner;
REVOKE EXECUTE ON FUNCTION keyspace1.user_function( int ) FROM report_writer;
REVOKE DESCRIBE ON ALL ROLES FROM role_admin;

Because of their function in normal driver operations, certain tables cannot have their SELECT permissions revoked. The following tables will be available to all authorized users regardless of their assigned role:

* `system_schema.keyspaces`
* `system_schema.columns`
* `system_schema.tables`
* `system.local`
* `system.peers`

LIST PERMISSIONS

Listing granted permissions uses the LIST PERMISSIONS statement:

list_permissions_statement ::= LIST permissions [ ON resource] [ OF role_name[ NORECURSIVE ] ]

For example:

LIST ALL PERMISSIONS OF alice;

Show all permissions granted to alice, including those acquired transitively from any other roles:

LIST ALL PERMISSIONS ON keyspace1.table1 OF bob;

Show all permissions on keyspace1.table1 granted to bob, including those acquired transitively from any other roles. This also includes any permissions higher up the resource hierarchy which can be applied to keyspace1.table1. For example, should bob have ALTER permission on keyspace1, that would be included in the results of this query. Adding the NORECURSIVE switch restricts the results to only those permissions which were directly granted to bob or one of `bob’s roles:

LIST SELECT PERMISSIONS OF carlos;

Show any permissions granted to carlos or any of carlos’s roles, limited to `SELECT permissions on any resource.