Configurable impresonnation

What is impersonnation

Hello I'm Bob, connect me as Alice.

Use cases:

• 1. Migration: migration user impersonnate existing user to migrate in/out emails of the user
• 2. Assistance: An admin impersonate a user to assist them with one problem...
• 3. Delegation: The secretary impersonnate her boss mails.

What exists today in James

Impersonation exists for IMAP AUTHENTICATE PLAIN.

Impersonation relies on the 'Authorizator' interface.

A simple implementation of it is provided: We then verify this the user performing the impersonation is an admin account defined in the configuration.

This makes it suitable for simple use cases defined in 1 and 2 (where multi-tenancy is not an issue)

However, this is unsuitable for more advanced use cases.

Proposal

Provide a configuration option to enable fine-grained authorization.

If enabled, a storage API for delegation will be enabled (stores user X have the right to impersonate to user Y). We can then have a webadmin API to manage this, as well as the wiring needed in the AUthorizator.