[Dovecot] Dovecot LDA, virtual users, multiple uids: No luck

[Toni Mueller]

Hi,

I'm trying to get Dovecot's deliver to create and use mailboxen with
one uid per user. Reading the wiki, I decided to go with the sudo
attempt, but I'm stuck because deliver fails to create the intermediate
directories. The auth.log has this on the matter:

sudo:  dovelda : TTY=unknown ; PWD=/var/spool/postfix ; USER=root ; COMMAND=/usr/lib/dovecot/deliver -f toni at bogus.oeko.net -d dick at example.com

Using strace on 'deliver', I get this:

# su - dovelda
$ echo "blubber" |sudo strace /usr/lib/dovecot/deliver -f toni at bogus.oeko.net  -d dick at example.com
...
geteuid()                               = 0
getgid()                                = 0
setgid(2000)                            = 0
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
setgroups(1, [2000])                    = 0
setuid(2100)                            = 0
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
setuid(0)                               = -1 EPERM (Operation not permitted)
getgid()                                = 2000
getegid()                               = 2000
setgid(0)                               = -1 EPERM (Operation not permitted)
close(6)                                = 0
geteuid()                               = 2100
geteuid()                               = 2100


and subsequently, creating the directories fails.


The values in the underlined lines above, 2100 and 2000, are from the
database entry of the user I want to deliver the email to.


My /etc/sudoers has this for dovelda:

dovelda ALL=NOPASSWD:/usr/lib/dovecot/deliver
dovelda ALL=NOPASSWD:/usr/bin/strace

I'm using a Debian/Lenny system with amd64 and this package for
Dovecot:

# dpkg -l 'dovecot*'
Desired=Unknown/Install/Remove/Purge/Hold
| Status=Not/Inst/Cfg-files/Unpacked/Failed-cfg/Half-inst/trig-aWait/Trig-pend
|/ Err?=(none)/Hold/Reinst-required/X=both-problems (Status,Err: uppercase=bad)
||/ Name           Version        Description
+++-==============-==============-============================================
ii  dovecot-common 1:1.2.13-1~bpo secure mail server that supports mbox and ma
ii  dovecot-imapd  1:1.2.13-1~bpo secure IMAP server that supports mbox and ma




Kind regards,
--Toni++