[Dovecot] Permission denied / missing +r perm

[Andrew Crawford]

I have postfix configured to deliver mail to dovecot over lmtp into a mailbox that then is accessed over imap.  The imap server is running as the user "mail". Whenever I run "postfix flush" I get in mail.log:

> Jun 12 05:37:45 li212-205 dovecot: lmtp(21288): Connect from local
> Jun 12 05:37:45 li212-205 spamd[18173]: prefork: child states: II
> Jun 12 05:37:45 li212-205 dovecot: auth-worker(21289): mysql(127.0.0.1): Connected to database mailserver
> Jun 12 05:37:45 li212-205 dovecot: lmtp(21288, drew at REDACTED): zXAqF2lBuFEoUwAA5SnFYQ: msgid=<064C5BC7-357B-4366-9A80-5001DBA21F62 at REDACTED>: saved mail to INBOX
> Jun 12 05:37:45 li212-205 postfix/lmtp[21287]: 57BDA1CC932: to=<drew at REDACTED>, relay=li212-205.members.linode.com[private/dovecot-lmtp], delay=0.06, delays=0.01/0.01/0.01/0.03, dsn=2.0.0, status=sent (250 2.0.0 <drew at REDACTED> zXAqF2lBuFEoUwAA5SnFYQ Saved)
> Jun 12 05:37:45 li212-205 dovecot: lmtp(21288): Disconnect from local: Client quit (in reset)
> Jun 12 05:37:45 li212-205 postfix/qmgr[21244]: 57BDA1CC932: removed
> Jun 12 05:37:45 li212-205 dovecot: imap(drew at REDACTED): Error: open(/decrypted-mail/awesomebox.sealedabstract.com/drew/cur/1371029865.M411903P21288.li212-205,S=2626,W=2673:2,) failed: Permission denied (euid=8(mail) egid=8(mail) missing +r perm: /decrypted-mail/awesomebox.sealedabstract.com/drew/cur/1371029865.M411903P21288.li212-205,S=2626,W=2673:2,, we're not in group 0(root))
> Jun 12 05:37:45 li212-205 dovecot: imap(drew at REDACTED): Disconnected: Internal error occurred. Refer to server log for more information. [2013-06-12 05:37:45] in=349 out=1084


Indeed, the file in question is owned by root and would not be accessible to the mail user:

> ls -la /decrypted-mail/awesomebox.sealedabstract.com/drew/cur/
> total 24
> drwxrw---- 2 mail mail 4096 Jun 12 05:37 .
> drwxrw---- 7 mail mail 4096 Jun 12 05:37 ..
> -rw-rw---- 1 mail mail 2616 Jun 12 05:26 1371029196.M462737P20302.li212-205,S=2616,W=2662:2,
> -rw-rw---- 1 mail mail 2635 Jun 12 05:32 1371029564.M454251P20747.li212-205,S=2635,W=2682:2,
> -rw-rw---- 1 root root 2626 Jun 12 05:37 1371029865.M411903P21288.li212-205,S=2626,W=2673:2,

So dutifully, I chown / chgrp to the mail user.  But as soon as i receive a new mail, dovecot again creates files owned by root:root.

How do I convince it to create files as mail:mail ?


Diagnostic info:

> $ dovecot --version
> 2.1.7

> $ ps -aux | grep dovecot
> root     20810  0.0  0.0   2892   984 ?        Ss   05:34   0:00 /usr/sbin/dovecot -c /etc/dovecot/dovecot.conf
> dovecot  20813  0.0  0.0   2620   940 ?        S    05:34   0:00 dovecot/anvil
> root     20814  0.0  0.1   2752  1072 ?        S    05:34   0:00 dovecot/log
> root     20818  0.0  0.2   4348  2524 ?        S    05:34   0:00 dovecot/config
> dovenull 21046  0.0  0.2   5248  2500 ?        S    05:35   0:00 dovecot/imap-login
> mail     21047  0.0  0.2   6392  2088 ?        S    05:35   0:00 dovecot/imap
> dovenull 21056  0.0  0.2   5248  2500 ?        S    05:35   0:00 dovecot/imap-login
> mail     21057  0.0  0.2   6752  2576 ?        S    05:35   0:00 dovecot/imap
> dovenull 21292  0.0  0.2   5248  2500 ?        S    05:37   0:00 dovecot/imap-login
> root     21293  0.0  0.1   4508  1044 ?        S    05:37   0:00 dovecot/ssl-params
> mail     21294  0.0  0.2   6540  2624 ?        S    05:37   0:00 dovecot/imap
> root     21400  0.0  0.0   4104   788 pts/0    S+   05:51   0:00 grep dovecot

> $ doveconf -n
> # 2.1.7: /etc/dovecot/dovecot.conf
> # OS: Linux 3.8.4-linode50 i686 Debian 7.0 fuse.encfs
> auth_mechanisms = plain login
> first_valid_uid = 0
> mail_location = maildir:/decrypted-mail/%d/%n
> mail_privileged_group = mail
> namespace inbox {
>   inbox = yes
>   location = 
>   mailbox Drafts {
>     special_use = \Drafts
>   }
>   mailbox Junk {
>     special_use = \Junk
>   }
>   mailbox Sent {
>     special_use = \Sent
>   }
>   mailbox "Sent Messages" {
>     special_use = \Sent
>   }
>   mailbox Trash {
>     special_use = \Trash
>   }
>   prefix = 
> }
> passdb {
>   args = /etc/dovecot/dovecot-sql.conf.ext
>   driver = sql
> }
> protocols = " imap lmtp"
> service auth-worker {
>   user = mail
> }
> service auth {
>   unix_listener /var/spool/postfix/private/auth {
>     group = postfix
>     mode = 0600
>     user = postfix
>   }
>   unix_listener auth-userdb {
>     mode = 0600
>     user = mail
>   }
>   user = dovecot
> }
> service imap-login {
>   inet_listener imap {
>     port = 0
>   }
> }
> service lmtp {
>   unix_listener /var/spool/postfix/private/dovecot-lmtp {
>     group = postfix
>     mode = 0666
>     user = postfix
>   }
>   user = mail
> }
> service pop3-login {
>   inet_listener pop3 {
>     port = 0
>   }
> }
> ssl = required
> ssl_cert = </etc/ssl/certs/dovecot.pem
> ssl_key = </etc/ssl/private/dovecot.pem
> userdb {
>   args = uid=mail gid=mail home=/decrypted-mail/%d/%n
>   driver = static
> }
>