RFC patch: Deny removal of folder owner ACLs

[Bron Gondwana]

On Thu, Dec 30, 2010 at 10:45:18AM +0100, Guilherme Maciel Ferreira wrote:

Gosh - sorry nobody responded to this!

> We were having problems with some users who deleted  all ACL rights
> from a folder, rendering the mailbox inaccessible.
> 
> There's already a feature in cyrus that the folder owner can't
> delete his own administration rights (implicit acls).
> 
> This left one hole in the protection which is still cumbersome to the users: 
> If user A has admin rights over user B's mailbox, user A can remove the admin 
> rights from user B, either by DELETEACL B, or by SETACL B with more 
> restrictive access rights.

That sounds like a bug in implicit acls to me.  They should be
implicit no matter what!
 
> So we changed the imap server to avoid such kind of behavior. The patch was 
> developed for version 2.3.16. It is possible to roll back to the default 
> behavior through the imapd.conf variable "owneralwaysadmin=no".

I think it would be reasonable to just tie it to implicit acls rather
than creating another switch.  That sound good to you?

I like the idea - and it would be great if you did a patch again git
master at http://git.cyrusimap.org/ - follow the links.  Or if you use
git you can just fork it and ask us to pull your branch!  That way you
get full credit :)

Bron.