Up until now, we have used Devise's Rememberable mechanism to re-log users
after the end of their browser sessions. This mechanism relies on a signed
cookie containing a token. That token was stored on the user's record,
meaning it was shared across all logged in browsers, meaning truly revoking
a browser's ability to auto-log-in involves revoking the token itself, and
revoking access from *all* logged-in browsers.
We had a session mechanism that dynamically checks whether a user's session
has been disabled, and would log out the user if so. However, this would only
clear a session being actively used, and a new one could be respawned with
the `remember_user_token` cookie.
In practice, this caused two issues:
- sessions could be revived after being closed from /auth/edit (security issue)
- auto-log-in would be disabled for *all* browsers after logging out from one
of them
This PR removes the `remember_token` mechanism and treats the `_session_id`
cookie/token as a browser-specific `remember_token`, fixing both issues.
While OAuth tokens were immediately revoked, accessing the home
controller immediately generated new OAuth tokens and "revived"
the session due to a combination of using remember_me tokens and
overwriting the `authenticate_user!` method
While making browser requests in the other sessions after a password
change or reset does not allow you to be logged in and correctly
invalidates the session making the request, sessions have API tokens
associated with them, which can still be used until that session
is invalidated.
This is a security issue for accounts that were already compromised
some other way because it makes it harder to throw out the hijacker.
