Remap login before authentication

[Miloslav Hůla]

Hi,

with Dovecot 2.3.4 I would like to allow user to login with two 
different usernames:

- USERNAME (no domain) - now works
- name.surname at domain.tld - would like to add

Problem is, that the only authentication method I have is LDAP bind by 
USERNAME. Now I use:

============
passdb {
   driver = ldap
   args = /etc/dovecot/dovecot-ldap.conf.ext
}

# Args
uris = ldaps://ldap.domain.tld
auth_bind = yes
auth_bind_userdn = uid=%u,dc=domain,dc=tld
base =
============

I know passdb can remap user&domain, but I have no password hash at all. 
And for example '{SASL}' is not supported password scheme to return e.g. 
from SQL passdb.


Is there any way how to achive this? Maybe somehow remap username in 
first passdb and then continue to LDAP bind?

1. login as name.surname at domain.tld
2. remap to USERNAME
3. do the LDAP bind


Milo