[Dovecot] /var/mail/<user> and mail group privileges

[Michal Hlavinka]

Hi Timo,

I'm facing problem with mail group privileges (again), because I've heard a 
few complains. I was looking at old emails and list archives, but still does 
not know the answer. In default (fedora/rhel) setup mail group and 0660 
privileges are used. This means that when 
     mail_location = mbox:~/mail:INBOX=/var/mail/%u
is used, dovecot fails with first (and only first) attempt to select inbox 
(imap) or login (pop3).

Shouldn't mkdir and chown make together a transaction? When it fails just for 
first time, it confuses some admins (this is the reason why I'm getting 
complains (bug reports) just because missing/wrong configuration). I think it 
a) should work even for first connection (ignore chown failure) or b)it should 
not work for following connection, so the behavior should be more consistent.

Also it seems unclear what configuration option is required for making this 
work in new dovecot versions where configuration is split to 
mail_privileged_group and mail_access_groups. I see that after reading 
documentation in 10-mail.conf, some admins expects mail_privileged_group to be 
enough while mail_access_group is required to prevent fchown failure. Would it 
be possible to explicitly mention in the config file what option is required? I 
can add patch with this to our rpm, but we always prefer to be as close to the 
upstream as possible. Thanks

Michal