Permissions management for SQL storage backend

This document aims to provide guidance to users for setting up and managing permissions when using the SQL storage backend.

Introduction

To handle permissions, Helm leverages the RBAC feature of Kubernetes. When using the SQL storage backend, Kubernetes' roles can't be used to determine whether or not an user can access a given resource. This document shows how to create and manage these permissions.

Initialization

The first time the Helm CLI will make connect to your database, the client will make sure that it was previously initialized. If it is not, it will take care of the necessary setup automatically. This initialization requires admin privileges on the public schema, or at least to be able to:

• create a table
• grant privileges on the public schema

After the migration was run against your database, all the other roles can use the client.

Grant privileges to a non admin user in PostgreSQL

To manage permissions, the SQL backend driver leverages the RLS(Row Security Level) feature of PostgreSQL. RLS allows all users to be able to read/write from/to the same table, without being able to manipulate the same rows if they are not explicitly allowed to. By default, any role that has not been explicitely granted with the right privileges will always return an empty list when running helm list and will not be able to retrieve or modify any resource in the cluster.

Let's see how to grant a given role access to specific namespaces:

CREATE POLICY <name> ON releases_v1 FOR ALL TO <role> USING (namespace = 'default');

This command will grant the permissions to read and write all resources that meet the namespace = 'default' condition to the role role. After creating this policy, the user being connected to the database on the behalf of the role role will therefore be able to see all the releases living in the default namespace when running helm list, and to modify and delete them.

Privileges can be managed granularly with RLS, and one might be interested in restraining access given the different columns of the table:

• key
• type
• body
• name
• namespace
• version
• status
• owner
• createdAt
• modifiedAt