dovecot - Feb 2015 - userdb passwd-file default_fields uid not expanding %variable

Hi all,

I'm trying to set up a very simple shared mail server, where each
'domain' is a system user, i.e. 'example.com' is a real user
with
/home/example.com/, a uid of 5001 (and gid 'example.com' of 5001).
Each domain\user has their own maildir inside their home, and a plain
passwd-file with the virtual mail users associated with that domain.

Version & config info:

# dovecot -n
# 2.2.13: /etc/dovecot/dovecot.conf
# OS: Linux 3.2.0-4-amd64 x86_64 Debian 7.8
auth_mechanisms = plain login
auth_verbose = yes
disable_plaintext_auth = no
mail_location = mbox:~/mail:INBOX=/var/mail/%u
namespace inbox {
  inbox = yes
  location   mailbox Drafts {
    special_use = \Drafts
  }
  mailbox Junk {
    special_use = \Junk
  }
  mailbox Sent {
    special_use = \Sent
  }
  mailbox "Sent Messages" {
    special_use = \Sent
  }
  mailbox Trash {
    special_use = \Trash
  }
  prefix }
passdb {
  args = username_format=%n /home/%d/mail_users
  driver = passwd-file
}
protocols = " imap lmtp pop3"
ssl = no
userdb {
  args = username_format=%n /home/%d/mail_users
  default_fields = uid=%d gid=%d home=/home/%d/mail/%n
mail=maildir:/home/%d/mail/%n
  driver = passwd-file
}

Every time I try to authenticate via imap, I get the error
> <timestamp> <host> dovecot: auth: Fatal: passwd-file userdb:
Invalid uid: %d

If I put fixed a uid and gid in the userdb default_fields line:
>   default_fields = uid=example.com gid=example.com home=/home/%d/mail/%n
mail=maildir:/home/%d/mail/%n
authentication passes without a problem, but of course, only for users
of example.com.

Checking the wiki
(http://wiki2.dovecot.org/UserDatabase#Userdb_settings) clearly states
that the default_fields values support %variables, so I'm not sure if
I'm missing some other config required for this to work.

Many thanks in advance,

Tim Jones
Software Development
+34 612345678
C/ Quintanavides 15, Edificio 2, Planta 1?
Parque Empresarial V?a Norte de Metrovacesa
Las Tablas
28050 Madrid
Skype: tim.jones.fon
All information in this email is confidential

First, sorry for the double post, not sure how that happened.

Secondly, I should add the userdb error happens as soon as any
connection attempt is map to the pop3\imap port, before a login
command can be sent. Obviously, since no login is started, there will
be no username from which to extract the %d domain name variable. So
the error makes sense.
My problem is that the userdb is being checked upon connection rather
than login, is there a way to bypass or disable that. Or maybe a
'failover' userdb to try if the correct one fails.

Many thanks,

Tim Jones
Software Development
+34 612345678
C/ Quintanavides 15, Edificio 2, Planta 1?
Parque Empresarial V?a Norte de Metrovacesa
Las Tablas
28050 Madrid
Skype: tim.jones.fon
All information in this email is confidential


On 27 February 2015 at 19:20, Tim Jones <tim.jones at fon.com>
wrote:
> Hi all,
>
> I'm trying to set up a very simple shared mail server, where each
> 'domain' is a system user, i.e. 'example.com' is a real
user with
> /home/example.com/, a uid of 5001 (and gid 'example.com' of 5001).
> Each domain\user has their own maildir inside their home, and a plain
> passwd-file with the virtual mail users associated with that domain.
>
> Version & config info:
>
> # dovecot -n
> # 2.2.13: /etc/dovecot/dovecot.conf
> # OS: Linux 3.2.0-4-amd64 x86_64 Debian 7.8
> auth_mechanisms = plain login
> auth_verbose = yes
> disable_plaintext_auth = no
> mail_location = mbox:~/mail:INBOX=/var/mail/%u
> namespace inbox {
>   inbox = yes
>   location >   mailbox Drafts {
>     special_use = \Drafts
>   }
>   mailbox Junk {
>     special_use = \Junk
>   }
>   mailbox Sent {
>     special_use = \Sent
>   }
>   mailbox "Sent Messages" {
>     special_use = \Sent
>   }
>   mailbox Trash {
>     special_use = \Trash
>   }
>   prefix > }
> passdb {
>   args = username_format=%n /home/%d/mail_users
>   driver = passwd-file
> }
> protocols = " imap lmtp pop3"
> ssl = no
> userdb {
>   args = username_format=%n /home/%d/mail_users
>   default_fields = uid=%d gid=%d home=/home/%d/mail/%n
> mail=maildir:/home/%d/mail/%n
>   driver = passwd-file
> }
>
> Every time I try to authenticate via imap, I get the error
>
>> <timestamp> <host> dovecot: auth: Fatal: passwd-file
userdb: Invalid uid: %d
>
>
> If I put fixed a uid and gid in the userdb default_fields line:
>
>>   default_fields = uid=example.com gid=example.com
home=/home/%d/mail/%n mail=maildir:/home/%d/mail/%n
>
> authentication passes without a problem, but of course, only for users
> of example.com.
>
> Checking the wiki
> (http://wiki2.dovecot.org/UserDatabase#Userdb_settings) clearly states
> that the default_fields values support %variables, so I'm not sure if
> I'm missing some other config required for this to work.
>
> Many thanks in advance,
>
> Tim Jones
> Software Development
> +34 612345678
> C/ Quintanavides 15, Edificio 2, Planta 1?
> Parque Empresarial V?a Norte de Metrovacesa
> Las Tablas
> 28050 Madrid
> Skype: tim.jones.fon
> All information in this email is confidential

-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1

On Fri, 27 Feb 2015, Tim Jones wrote:
> userdb {
>  args = username_format=%n /home/%d/mail_users
>  default_fields = uid=%d gid=%d home=/home/%d/mail/%n
> mail=maildir:/home/%d/mail/%n
>  driver = passwd-file
> }
>
> Every time I try to authenticate via imap, I get the error
>
>> <timestamp> <host> dovecot: auth: Fatal: passwd-file
userdb: Invalid uid: %d
Putting aside the question, whether or not %d is/should be expanded in 
default_fields = uid=%d gid=%d
couldn't or shouldn't you place the correct numerical ids in the file 
anyway?
> If I put fixed a uid and gid in the userdb default_fields line:
>
>>   default_fields = uid=example.com gid=example.com
home=/home/%d/mail/%n mail=maildir:/home/%d/mail/%n
>
> authentication passes without a problem, but of course, only for users
> of example.com.
- -- 
Steffen Kaiser
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> Putting aside the question, whether or not %d is/should be expanded in
> default_fields = uid=%d gid=%d
> couldn't or shouldn't you place the correct numerical ids in the
file
> anyway?
The issue is, and maybe this was a bad requirement on my part, that
each domains' mailbox is owned by the user associated with that
domain. I don't have a global 'virtualmail' user that handles the
mailboxes. Each 'domain' hosted on the server is a system user, with
their own PHP instance, Python virtualenv etc, and maildir inside
$HOME. So until the client issues a log in, I don't know which uid\gid
to assign to them.

Many thanks,

Tim Jones
Software Development
+34 612345678
C/ Quintanavides 15, Edificio 2, Planta 1?
Parque Empresarial V?a Norte de Metrovacesa
Las Tablas
28050 Madrid
Skype: tim.jones.fon
All information in this email is confidential