LDA ignores virtual mailbox settings

[Toni Mueller]

Hi,

thanks to all the people who tried to help me. I have made one more
step into the right direction and wanted to share my findings.


To recap, LDA pulls the right data from userdb, then ignores it and
tries to deliver to the system default maibox location at /var/mail:

On Sun, Dec 27, 2020 at 04:19:35PM +0000, Toni Mueller wrote:
> 16:04:16 dovecot: auth: Debug: userdb out: USER#0111#011user at example.com#011home=/path-to-mailboxen/example.com/user#011uid=12345#011gid=12345#011quota_rule=*:storage=0
> 
> ^^^^^^^^^^^^^^^^^^^^^^
> 
> This shows that the database lookup works. The intended effect should be
> that the message is delivered to
> 
> /path-to-mailboxen/example.com/user/Maidir/new
> 
> 
> 16:04:16 dovecot: lda(user at example.com)<5291><DDxBHYCw6F+rFAAApiCoHg>: Error: Mailbox INBOX: open(/var/mail/user at example.com) failed: Permission denied (euid=12345(mailbox) egid=12345(mailbox) missing +w perm: /var/mail, we're not in group 8(mail), dir owned by 0:8 mode=0775)
> 
> ^^^^^^^^^^^^^^^^^^^^^^
> 
> And this shows that dovecot-lda just ignores the result.

1. Directive merging:

I found that there may be a problem in merging configuration directives.
In Debian, the main config file is /etc/dovecot/dovecot.conf. This
includes some snippets in /etc/dovecot/conf.d, and, at last, includes
/etc/dovecot/local.conf.

In /etc/dovecot/conf.d/10-mail.conf, there are these two statements:

mail_location = mbox:~/mail:INBOX=/var/mail/%u
mail_privileged_group = mail

In local.conf, I have different values for that, but only if I comment
them out in 10-mail.conf, I get LDA to try to deliver to the directory
where it should deliver. Therefore, I assume that later directives are
not overwriting earlier directives, but "first wins" is an uncommon
strategy - usually, it's "last wins". I'm not sure whether this is a bug
or not, though, but a quick search did not reveal how things are
supposed to be.


2. Wrong mailbox settings:

I want to deliver to maildir and have these settings: Globally, ie,
outside of all "blocks" (<token> [<name>] { ... }), I have

mail_location = maildir:~/Maildir:INBOX=maildir:~/Maildir

In addition to that, I have this:

namespace inbox {
  inbox = yes
  location = maildir:~/Maildir
}


But Dovecot wrote the mail to a file in mbox format, and the file being
at ~/mail/inbox, with ~ being the home dir as taken from the SQL
database.


3. Autocreate fails:

I now have this for LDA and IMAP:

-------- cut
protocol imap {
  mail_plugins =  autocreate quota imap_quota mail_log trash virtual notify
  mail_max_userip_connections = 10
}

protocol lda {
  mail_plugins = autocreate quota virtual mail_log trash notify
  ...
}
-------- cut

In the first instance, the home from the database was created by
Dovecot, but then I moved it aside, so as to have Dovecot create a new
one. But now I get this, even after lifting the plugin settings of LDA
to the global scope:

Jan  1 15:07:52 dovecot: lda(user at example.com)<13951><FVyCAMg6719/NgAApiCoHg>: Fatal: Namespace '': Mail storage autodetection failed with home=/path-to-mailboxen/example.com/user

Setting 'mail_location', as was suggested numerous times on the
Internet, does not seem to have the desired effect, and I only have the
'inbox' namespace, anyway.


Any ideas, please?


TIA!



Cheers,
Toni