Project: CockroachDB (App Definition and Development / Database)
File: 20200720_finer_grained_role_privileges.md

Feature Name: Finer-grained Role Privileges Status: draft Start Date: 2020-07-21 Authors: Solon Gordon, Joel Kenny CockroachDB offers a built-in "admin" role which can be granted in order to give users a wide range of privileges. For one thing, it grants full permissions on all objects in the database. But there are also a number of operations which only admins are permitted to perform, like creating a new database or changing cluster settings. Since these operations can only be performed by admins, it's currently impossible to grant a user the ability to perform any one of these operations without giving them full admin access. This document proposes adding new role-level privileges so that admin-like abilities can be granted in a more fine-grained manner. One major motivator for these changes is CockroachCloud. When we create the initial user for a CockroachCloud cluster, we currently grant the admin role to that user so they can perform basic operations like creating new databases. However, this also gives that user the ability to perform actions which could damage their cluster, like deleting the user which is used for automatic backup. Rather than granting the admin role, the CockroachCloud team would like the ability to create an "operator" role which only grants whatever abilities are necessary for the user to administer their cluster. These new options will also be useful for customers who want to grant users administrative abilities without managing the security of their cluster by limiting the number of people with true admin access. As of v20.1, CockroachDB supports a few role-level options which can be granted via the `CREATE ROLE` or `ALTER ROLE` statement. One example is `CREATEROLE`, which grants users the ability to create, alter, and drop other roles. A complete list is available at https://www.cockroachlabs.com/docs/v20.1/alter-role.html#parameters. In order to support granting admin-like abilities, we add several new role options: Allows a user to create new databases. The user who issues the command is the owner of the database in question. This confers the ability to rename the database via `ALTER DATABASE ... RENAME`. Allows a user to manage authentication. This grants access to: the `WITH PASSWORD` clause for `CREATE/ALTER USER/ROLE` the `VALID UNTIL` clause for `CREATE/ALTER USER/ROLE` `ALTER USER/ROLE CREATELOGIN/NOCREATELOGIN` `ALTER USER/ROLE LOGIN/NOLOGIN` Note that these abilities were previously available to users with the CREATEROLE option. For backward compatibility, a 20.2 migration grants CREATELOGIN to all users who previously had CREATEROLE. As noted above, we already support this option. However, it currently does not prevent a non-admin user from dropping an admin. We will add this restriction to protect against dropping essential admin users. Allows a user to pause, resume, and cancel jobs. Non-admin users cannot control jobs created by admins. Allows users to cancel queries and sessions of other users. Without this privilege, users can only cancel their own queries and sessions. Even with this privilege, non-admins cannot cancel admin queries or sessions. This option should usually be combined with VIEWACTIVITY so that the user can view other user's query and session information. Allows a user to see other users' queries and sessions via the following means: SHOW QUERIES SHOW SESSIONS the WebUI Statements and Transactions pages Without this privilege, the SHOW commands only show the user's own data, and the WebUI pages are

Allows users to run `CREATE CHANGEFEED` on tables they have `SELECT` privileges on. In the future this should also control whether a user can pause, resume, or cancel a changefeed, but that is currently controlled via job control so will be determined by the `CONTROLJOB` option. Allows a user to modify certain cluster settings. At present this allows modifying any setting with the `sql.defaults` prefix, but this list may be expanded in the future. We also add the ability for non-admin users to perform certain BACKUP, RESTORE, and IMPORT INTO operations. Rather than enabling this via a new role option, we do so based on existing privileges. Database and table backups require SELECT privileges on the target object. User-defined type and schema backups require the USAGE privilege. RESTOREs require CREATE privileges on all restored objects and CREATEDB in the case of database restores. IMPORT INTO requires INSERT and DROP on the target table. (DROP is required because the IMPORT implementation makes the table unavailable for the duration of the operation.) Full cluster and tenant BACKUP and RESTORE continue to require admin. We also restrict what source URLs non-admins can use for these operations. nodelocal, HTTP, and AWS/GCS/Azure sources which rely on implicit credentials will continue to require the admin role. This is acceptable for the Cockroach Cloud use case since that system uses explicit, temporary credentials for RESTORE. The backend implementation of these new privileges should be straightforward. Role-level options are already stored in the `system.role_options` table and no migration is necessary to add new options. We will add the new privileges to our list of supported role options and assert that a user has the appropriate role option (or is an admin) when performing the associated operation. The new privileges proposed here do not include a way to guarantee that a role has privileges on all objects in the cluster. This remains a unique property of the admin role. This may present a problem for CockroachCloud, since the customer will not have access to any admin users, so there will be no user who has reliable access to all objects. However, adding a mechanism for granting non-admins cluster-wide access is also undesirable, because there are some databases and tables which we don't want them to have access to. One example of this is tables which we use to manage automatic backups. However, the CockroachCloud team could mitigate this by enhancing their management console to allow operators to modify privileges. For example, the console could allow altering the owner of database objects. That way a user could switch the owner to themself or the operator role if they needed access to a given object. Behind the scenes, these privileges changes would be performed by an admin user which is not exposed to the customer. Rather than making CONTROLCHANGEFEED a role option, we could consider making it a privilege at the database/schema/table level. This would provide more granular control but seems less desirable in a few ways: Since the owner of an object receives all privileges on it, creating a table would give a user the ability to create a changefeed, which might not be desired. It's not clear if there is a realistic scenario where a user should only have the ability to create changefeeds on only certain tables they have read access to.