Daniel, Just wanted to respond back and let you know that changing permissions to dovecot:dovecot as you suggested seems to have resolved the issue; I've not seen any more occurrences of this error.
Thanks again for your assistance! Chris On Sun, March 3, 2013 5:13 pm, Daniel Parthey wrote: > Hi Chris, > > Chris Richards wrote: >> service auth { >> unix_listener /var/spool/postfix/private/auth { >> group = postfix >> mode = 0666 >> user = postfix >> } >> unix_listener auth-userdb { >> group = vmail >> mode = 0600 >> user = vmail >> } >> user = $default_internal_user >> } > > In order for dovecot-lda to work, default internal user "dovecot" > seems to need permission for the user listing. This should work, > but you should try to narrow the permissions down: > > service auth { > unix_listener auth-userdb { > group = dovecot > mode = 0666 > user = dovecot > } > } > > Documentation http://wiki2.dovecot.org/LDA says: > > The auth-userdb socket can be used to do userdb lookups for given > usernames or > get a list of all users. Typically the result will contain the user's UID, > GID > and home directory, but depending on your configuration it may return > other > information as well. So the information is similar to what can be found > from > eg. /etc/passwd for system users. This means that it's probably not a > problem > to use mode=0666 for the socket, but you should try to restrict it more > just to > be safe. > >> hermes conf.d # stat /usr/libexec/dovecot/deliver >> File: '/usr/libexec/dovecot/deliver' -> 'dovecot-lda' >> Size: 11 Blocks: 0 IO Block: 4096 symbolic >> link >> Device: 805h/2053d Inode: 267375 Links: 1 >> Access: (0777/lrwxrwxrwx) Uid: ( 0/ root) Gid: ( 0/ root) >> Access: 2012-11-24 17:44:04.440976879 +0000 >> Modify: 2012-11-24 17:44:04.440976879 +0000 >> Change: 2012-11-24 17:44:04.440976879 +0000 >> Birth: - > > deliver is a symbolic link to dovecot-lda, so its basically the same. > >> hermes conf.d # stat /usr/libexec/dovecot/dovecot-lda >> File: '/usr/libexec/dovecot/dovecot-lda' >> Size: 22432 Blocks: 48 IO Block: 4096 regular file >> Device: 805h/2053d Inode: 849010 Links: 1 >> Access: (0755/-rwxr-xr-x) Uid: ( 0/ root) Gid: ( 0/ root) >> Access: 2012-11-24 17:43:57.124794021 +0000 >> Modify: 2012-11-24 17:44:02.204920992 +0000 >> Change: 2012-11-24 17:44:04.444976978 +0000 >> Birth: - > > No setuid/setgid flags set. > >> >> In Postfix master.cf, I have the following: >> >> dovecot unix - n n - - pipe >> >> flags=DRhu user=vmail:users argv=/usr/libexec/dovecot/deliver -f >> >> ${sender} -d ${user}@${nexthop} > > I'm wondering why user=vmail:users does not have the desired effect > and dovecot-lda uses the effective uid "dovecot" and effective gid > "dovecot" > to do the user lookups. > > Regards > Daniel