[Dovecot] Clash between multiple authentication databases(security problem?) [SOLVED]

[dovecot-ri]

Timo Sirainen wrote:
> On Thu, 2006-02-02 at 12:24 -0500, dovecot-ri wrote:
> > Hi all,
> >
> > I just installed dovecot-1.0_beta2 and love it!  However, I've run into
> issues using multiple authentication databases.
> >
> > I use both pam (for users on my system) and sql (for virtual users).
> I've noticed that if I have system user "userabc" and virtual user
> "userabc at otherdomain.com" (two distinct users) and my "auth default"
> section contains these passdb/userdb entries in this order (the order in
> the example config):
> >
> >   passdb pam
> >   passdb sql
> >   userdb pam
> >   userdb sql
> ..
> > then when userabc at otherdomain.com logs in, he'll get the system user
> userabc's mail instead of his own.  It appears that the sql password check
> succeeds, then Dovecot grabs the home directory from pam, NOT sql.
> 
> Yes, because passdbs and userdbs aren't tied together. It always goes
> through them in order.
> 
> > Is there a safer way to do this?  If not, should there be?
> 
> Why is userdbc at otherdomain.com found from passwd? If there was only
> "userabc" in passwd and "userabc at otherdomain.com" in SQL, there should
> be no conflicts since they'd be completely different usernames.
> 
> Anyway I'm not sure if I can do anything about this in Dovecot's side.
> Unless maybe if I added some kind of optional relationships so you could
> configure what userdb to use when a user is found from one passdb..


I finally spent the time to properly debug this.  Turns out my passdb sql query was returning "userabc" instead of "userabc at otherdomain.com" in the "user" field.  This caused dovecot to switch to "userabc" when looking up userdb stuff (as evidenced by "username changed userabc at otherdomain.com -> userabc" in my dovecot logs).

Now I have another problem, but I'll send a separate e-mail to ask about it.