[Dovecot] dovecot ignoring folder permissions on directory creation

[Peter]

Ubuntu 8.04lts
Dovecot 1.2.6

So, further to the 'deliver' problem posted yesterday I've also discovered
another issue regarding permissions: files and directories are being created
0600/0700 by the IMAP and deliver process (depending on who gets there
first!) preventing use of shared mailboxes.

According to documentation:
"When creating a new mailbox, Dovecot v1.2+ copies the permissions from the
mailbox root directory."
and
"When creating new files inside a mailbox, Dovecot v1.2+ copies the
read/write permissions from the mailbox's directory."
(http://wiki.dovecot.org/SharedMailboxes/Permissions)

So, with an empty directory of:

drwxr-xr-x 3 root   root     21 2009-11-16 13:36 /home
drwxrwx--x 3 nobody maildir  21 2009-11-16 13:36 /home/mail

I would expect a user logging in to have their mail directory created
automatically with the same permissions (but not necessarily the same
group).

What I see post-login is:

drwxrwx--x 3 nobody maildir   21 2009-11-16 13:42 /home/mail
drwx------ 3 auser  adomain   18 2009-11-16 13:42 /home/mail/adomain
drwx------ 3 auser  adomain   20 2009-11-16 13:42 /home/mail/adomain/auser
drwx------ 5 auser  adomain 4096 2009-11-16 13:42
/home/mail/adomain/auser/Maildir
drwx------ 2 auser  adomain    6 2009-11-16 13:42
/home/mail/adomain/auser/Maildir/cur
-rw------- 1 auser  adomain    0 2009-11-16 13:42
/home/mail/adomain/auser/Maildir/dovecot-acl-list
-rw------- 1 auser  adomain  156 2009-11-16 13:42
/home/mail/adomain/auser/Maildir/dovecot.index.log
-rw------- 1 auser  adomain   17 2009-11-16 13:42
/home/mail/adomain/auser/Maildir/dovecot-uidlist
-rw------- 1 auser  adomain    8 2009-11-16 13:42
/home/mail/adomain/auser/Maildir/dovecot-uidvalidity
-rw------- 1 auser  adomain    0 2009-11-16 13:42
/home/mail/adomain/auser/Maildir/dovecot-uidvalidity.4b0156e2
drwx------ 2 auser  adomain    6 2009-11-16 13:42
/home/mail/adomain/auser/Maildir/new
drwx------ 2 auser  adomain    6 2009-11-16 13:42
/home/mail/adomain/auser/Maildir/tmp

I've tried pre-creation of /home/mail/adomain, /home/mail/adomain/auser and
/home/mail/adomain/auser/Maildir in each case with permissions 0770 but in
each case subsequent subdirectories and files are 0700/0600.

I've also tried use of a "dovecot-shared" file, but this also has no effect
under any permutation I can create.

Anyone else seen this?