Security¶

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
                          | 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 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 below), 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.

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 role_name WITH role_options

For instance:

ALTER ROLE bob WITH PASSWORD = 'PASSWORD_B' AND SUPERUSER = false;

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 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 instance:

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 instance:

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. And:

LIST ROLES OF alice;

enumerates all roles granted to alice, including those transitively acquired. But:

LIST ROLES OF bob NORECURSIVE

lists all roles directly granted to bob without including any of the transitively acquired ones.

CREATE USER¶

Creating a user uses the CREATE USER statement:

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

For instance:

CREATE USER alice WITH PASSWORD 'password_a' SUPERUSER;
CREATE USER bob WITH PASSWORD 'password_b' NOSUPERUSER;

CREATE USER 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 EXISTS alice WITH PASSWORD 'password_a' SUPERUSER;
CREATE ROLE IF 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' WITH LOGIN = true;

CREATE USER alice WITH PASSWORD 'password_a';
CREATE ROLE alice WITH PASSWORD = 'password_a' WITH LOGIN = true;

ALTER USER¶

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

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

For instance:

ALTER USER alice WITH PASSWORD 'PASSWORD_A';
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.

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 instance:

GRANT SELECT ON ALL KEYSPACES TO data_reader;

This 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;

This 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;

This gives any user with the schema_owner role permissions to DROP keyspace1.table1:

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

This 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

REVOKE PERMISSION¶

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

revoke_permission_statement ::=  REVOKE permissions ON resource FROM role_name

For instance:

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 instance:

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.