dovecot - Jul 2015 - Dovecot LMTP tries to access a directory of a different user, than the one it actually changed to.

Hello, I encountered a problem when trying to send an email to multiple 
recipients.


=== LOG ==
... cut ...
Jul  3 12:34:57 dhcp90 dovecot: lmtp(24106): Debug: none: root=, index=, 
control=, inboxJul  3 12:34:57 dhcp90 dovecot: lmtp(24106): Connect from local
Jul  3 12:34:57 dhcp90 dovecot: lmtp(24106): Debug: Loading modules from 
directory: /usr/lib64/dovecot
Jul  3 12:34:57 dhcp90 dovecot: lmtp(24106): Debug: Module loaded: 
/usr/lib64/dovecot/lib90_sieve_plugin.so
Jul  3 12:34:57 dhcp90 dovecot: lmtp(24106): Debug: auth input: han.solo 
system_groups_user=han.solo uid=805 gid=800 home=/home/han.solo
Jul  3 12:34:57 dhcp90 dovecot: lmtp(24106): Debug: auth input: tester 
system_groups_user=tester uid=802 gid=800 home=/home/tester
Jul  3 12:34:57 dhcp90 dovecot: lmtp(24106): Debug: auth input: vader 
system_groups_user=vader uid=804 gid=800 home=/home/vader
Jul  3 12:34:57 dhcp90 dovecot: lmtp(24106, han.solo): Debug: Effective 
uid=805, gid=800, home=/home/han.solo
Jul  3 12:34:57 dhcp90 dovecot: lmtp(24106, han.solo): Debug: fs: 
root=/home/han.solo/mail, index=, control=, inbox=/var/mail/han.solo
Jul  3 12:34:57 dhcp90 dovecot: lmtp(24106, han.solo): Debug: 
70NxN1FlllUqXgAA0vrzwA: sieve: user's script path 
/home/han.solo/.dovecot.sieve doesn't exist (using global script path in 
stead)
Jul  3 12:34:57 dhcp90 dovecot: lmtp(24106, han.solo): Debug: 
70NxN1FlllUqXgAA0vrzwA: sieve: user has no valid personal script
Jul  3 12:34:57 dhcp90 dovecot: lmtp(24106, han.solo): Debug: 
70NxN1FlllUqXgAA0vrzwA: sieve: no scripts to execute: reverting to 
default delivery.
Jul  3 12:34:57 dhcp90 dovecot: lmtp(24106, han.solo): 
70NxN1FlllUqXgAA0vrzwA: msgid=<55966551.IfKOMu/T0WTB9M5x%vader at 
dhcp90.#####>: saved mail to INBOX
Jul  3 12:34:57 dhcp90 dovecot: lmtp(24106, tester): Debug: Effective 
uid=802, gid=800, home=/home/tester
Jul  3 12:34:57 dhcp90 dovecot: lmtp(24106, tester): Debug: fs: 
root=/home/tester/mail, index=, control=, inbox=/var/mail/tester
Jul  3 12:34:57 dhcp90 dovecot: lmtp(24106, tester): Debug: 
70NxN1FlllUqXgAA0vrzwA: sieve: user's script path 
/home/tester/.dovecot.sieve doesn't exist (using global script path in 
stead)
Jul  3 12:34:57 dhcp90 dovecot: lmtp(24106, tester): Debug: 
70NxN1FlllUqXgAA0vrzwA: sieve: user has no valid personal script
Jul  3 12:34:57 dhcp90 dovecot: lmtp(24106, tester): Debug: 
70NxN1FlllUqXgAA0vrzwA: sieve: no scripts to execute: reverting to 
default delivery.
Jul  3 12:34:57 dhcp90 dovecot: lmtp(24106, tester): Error: 
stat(/home/han.solo/mail/.imap/INBOX/dovecot.index.log) failed: 
Permission denied (euid=802(tester) egid=800(kerber) missing +x perm: 
/home/han.solo, euid is not dir owner)
Jul  3 12:34:57 dhcp90 dovecot: lmtp(24106, tester): Error: 
open(/home/han.solo/mail/.imap/INBOX/dovecot.index) failed: Permission 
denied (euid=802(tester) egid=800(kerber) missing +x perm: 
/home/han.solo, euid is not dir owner)
Jul  3 12:34:57 dhcp90 dovecot: lmtp(24106, tester): 
70NxN1FlllUqXgAA0vrzwA: msgid=<55966551.IfKOMu/T0WTB9M5x%vader at 
dhcp90.#####>: save failed to INBOX: BUG: Unknown internal error
Jul  3 12:34:57 dhcp90 sendmail[24121]: t63AYvn5024116: to=<tester at 
dhcp90.#####>, ctladdr=<vader at dhcp90.#####> (804/800), 
delay=00:00:00, xdelay=00:00:00, mailer=local, pri=91062, 
relay=localhost, dsn=4.2.0, stat=Deferred: 451 4.2.0 <tester> BUG: 
Unknown internal error
Jul  3 12:34:57 dhcp90 dovecot: lmtp(24106, vader): Debug: Effective 
uid=804, gid=800, home=/home/vader
Jul  3 12:34:57 dhcp90 dovecot: lmtp(24106, vader): Debug: fs: 
root=/home/vader/mail, index=, control=, inbox=/var/mail/vader
Jul  3 12:34:57 dhcp90 dovecot: lmtp(24106, vader): Debug: 
70NxN1FlllUqXgAA0vrzwA: sieve: user's script path 
/home/vader/.dovecot.sieve doesn't exist (using global script path in stead)
Jul  3 12:34:57 dhcp90 dovecot: lmtp(24106, vader): Debug: 
70NxN1FlllUqXgAA0vrzwA: sieve: user has no valid personal script
Jul  3 12:34:57 dhcp90 dovecot: lmtp(24106, vader): Debug: 
70NxN1FlllUqXgAA0vrzwA: sieve: no scripts to execute: reverting to 
default delivery.
Jul  3 12:34:57 dhcp90 dovecot: lmtp(24106, vader): Error: 
stat(/home/han.solo/mail/.imap/INBOX/dovecot.index.log) failed: 
Permission denied (euid=804(vader) egid=800(kerber) missing +x perm: 
/home/han.solo, euid is not dir owner)
Jul  3 12:34:57 dhcp90 dovecot: lmtp(24106, vader): Error: 
open(/home/han.solo/mail/.imap/INBOX/dovecot.index) failed: Permission 
denied (euid=804(vader) egid=800(kerber) missing +x perm: 
/home/han.solo, euid is not dir owner)
Jul  3 12:34:57 dhcp90 dovecot: lmtp(24106, vader): 
70NxN1FlllUqXgAA0vrzwA: msgid=<55966551.IfKOMu/T0WTB9M5x%vader at 
dhcp90.#####>: save failed to INBOX: BUG: Unknown internal error
Jul  3 12:34:57 dhcp90 sendmail[24121]: t63AYvn5024116: to=<vader at 
dhcp90.#####>, ctladdr=<vader at dhcp90.#####> (804/800), 
delay=00:00:00, xdelay=00:00:00, mailer=local, pri=91062, 
relay=localhost, dsn=4.2.0, stat=Deferred: 451 4.2.0 <vader> BUG: 
Unknown internal error
Jul  3 12:34:57 dhcp90 sendmail[24121]: t63AYvn5024116: to=<han.solo at 
dhcp90.#####>, ctladdr=<vader at dhcp90.#####> (804/800), 
delay=00:00:00, xdelay=00:00:00, mailer=local, pri=91062, 
relay=localhost, dsn=2.0.0, stat=Sent
Jul  3 12:34:57 dhcp90 dovecot: lmtp(24106): Disconnect from local: 
Client quit
==========


The setup is as follows:
All users have /bin/false instead of a shell.
Each user has a unique UID but they all have 1 GID (800)
My MTA is sendmail
I am using dovecot-lmtp for local delivery
Mailbox format is mbox
Configured managesieve plugin to listen on 4190. (not sure if this is 
even related but it might)

The problem I see is that lmtp(user1) tries to access the home directory 
/home/user2 and I cannot figure out the reason why.
This only happens when sending mails to multiple recipients.
I see the that lmtp complains that it doesn't have execute permissions. 
But I don't want to place execute permissions for others on the entire 
/home/* dir structure.
Also, 700 are the default creation permissions. So new users would have 
to be chmod'ed manually. (unless there is a setting in dovecot)

I used "mailx" to send a test email to multiple recipients
`echo "test message" | mailx -s "subject" -r vader at
dhcp90.#####
han.solo at dhcp90.##### vader at dhcp90.##### tester at dhcp90.#####`
The only one who actually receives the message is han.solo at 
dhcp90.##### and

The same happens with aliases in /etc/aliases.
`echo "group test" | mailx -s "subject" -r vader at
dhcp90.#####
grouplist at dhcp90.#####`
"grouplist" is defined in /etc/aliases and contains the same users as
in
the log

Any help with this is greatly appreciated.

Here is my dovecot configuration:

=== `dovecot -n` ==# 2.0.9: /etc/dovecot/dovecot.conf
# OS: Linux 2.6.32-504.12.2.el6.x86_64 x86_64 CentOS release 6.6 (Final)
auth_debug = yes
auth_mechanisms = plain login
disable_plaintext_auth = no
lda_mailbox_autocreate = yes
mail_debug = yes
mail_full_filesystem_access = yes
mail_gid = mail
mail_location = mbox:~/mail:INBOX=/var/mail/%u
managesieve_notify_capability = mailto
managesieve_sieve_capability = fileinto reject envelope 
encoded-character vacation subaddress comparator-i;ascii-numeric 
relational regex imap4flags copy include variables body enotify 
environment mailbox date
mbox_write_locks = fcntl
passdb {
   driver = pam
}
plugin {
   sieve = ~/.dovecot.sieve
   sieve_dir = ~/sieve
}
protocols = imap pop3 lmtp sieve
service lmtp {
   client_limit = 1
   executable = /usr/libexec/dovecot/lmtp -L
   inet_listener lmtp {
     address = 127.0.0.1 ::1
     port = 24
   }
   process_min_avail = 1
}
service managesieve-login {
   inet_listener sieve {
     port = 4190
   }
}
ssl_cert = </etc/pki/dovecot/certs/dovecot.pem
ssl_key = </etc/pki/dovecot/private/dovecot.pem
userdb {
   driver = passwd
}
protocol lmtp {
   mail_plugins = " sieve"
   postmaster_address = postmaster
}
==============`rpm -qa | grep dovecot`
dovecot-pigeonhole-2.0.9-8.el6_6.4.x86_64
dovecot-2.0.9-8.el6_6.4.x86_64

Thanks in advance.


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On Fri, 3 Jul 2015, Ernest Deak wrote:
> Hello, I encountered a problem when trying to send an email to multiple 
> recipients.
> Jul  3 12:34:57 dhcp90 dovecot: lmtp(24106, tester): Error: 
> stat(/home/han.solo/mail/.imap/INBOX/dovecot.index.log) failed: Permission 
> denied (euid=802(tester) egid=800(kerber) missing +x perm: /home/han.solo, 
> euid is not dir owner)
> Jul  3 12:34:57 dhcp90 dovecot: lmtp(24106, tester): Error: 
> open(/home/han.solo/mail/.imap/INBOX/dovecot.index) failed: Permission
denied
> (euid=802(tester) egid=800(kerber) missing +x perm: /home/han.solo, euid is
> not dir owner)
> Jul  3 12:34:57 dhcp90 dovecot: lmtp(24106, tester):
70NxN1FlllUqXgAA0vrzwA:
> msgid=<55966551.IfKOMu/T0WTB9M5x%vader at dhcp90.#####>: save failed
to
> INBOX: BUG: Unknown internal error
> My MTA is sendmail
> I am using dovecot-lmtp for local delivery
> Mailbox format is mbox
> Configured managesieve plugin to listen on 4190. (not sure if this is even 
> related but it might)
>
> The problem I see is that lmtp(user1) tries to access the home directory 
> /home/user2 and I cannot figure out the reason why.
> This only happens when sending mails to multiple recipients.
> I see the that lmtp complains that it doesn't have execute permissions.
But I
> don't want to place execute permissions for others on the entire
/home/* dir
> structure.
as far as I remember there had been (or is) a bug in Dovecot, that 
privilegues are not changed correctly when delivering to another user. If 
that's the case, limit the number of recipients per LMTP message to 1, see 
r= field in mailer definition in op.me.

- -- 
Steffen Kaiser
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On Friday 03 of July 2015, Ernest Deak wrote:
> Hello, I encountered a problem when trying to send an email to multiple
> recipients.
That bug exists for some time

http://www.dovecot.org/list/dovecot/2014-September/097688.html

but no solution exists and I think no one actually tried to fix it.

(no solution beside already mentioned ugly workaround with limiting to 1 
recipient per lmtp session)

-- 
Arkadiusz Mi?kiewicz, arekm / ( maven.pl | pld-linux.org )

Adding r= field into the Mlocal definition of sendmail.cf worked out.
However, I dug around the documentation and found a macro one can define
to achieve this without having to mess around with the .cf file.

I am adding this here for anyone who might encounter the same problem.

In an .mc file, you can write:

define(`LOCAL_MAILER_MAXRCPTS',`1')

To achieve the same effect.

Thanks to all for the hints.

On 03.07.2015 15:09, Steffen Kaiser wrote:
> -----BEGIN PGP SIGNED MESSAGE-----
> Hash: SHA1
>
> On Fri, 3 Jul 2015, Ernest Deak wrote:
>
>> Hello, I encountered a problem when trying to send an email to 
>> multiple recipients.
>
>> Jul  3 12:34:57 dhcp90 dovecot: lmtp(24106, tester): Error: 
>> stat(/home/han.solo/mail/.imap/INBOX/dovecot.index.log) failed: 
>> Permission denied (euid=802(tester) egid=800(kerber) missing +x perm: 
>> /home/han.solo, euid is not dir owner)
>> Jul  3 12:34:57 dhcp90 dovecot: lmtp(24106, tester): Error: 
>> open(/home/han.solo/mail/.imap/INBOX/dovecot.index) failed: 
>> Permission denied (euid=802(tester) egid=800(kerber) missing +x perm: 
>> /home/han.solo, euid is not dir owner)
>> Jul  3 12:34:57 dhcp90 dovecot: lmtp(24106, tester): 
>> 70NxN1FlllUqXgAA0vrzwA: msgid=<55966551.IfKOMu/T0WTB9M5x%vader at 
>> dhcp90.#####>: save failed to INBOX: BUG: Unknown internal error
>
>> My MTA is sendmail
>> I am using dovecot-lmtp for local delivery
>> Mailbox format is mbox
>> Configured managesieve plugin to listen on 4190. (not sure if this is 
>> even related but it might)
>>
>> The problem I see is that lmtp(user1) tries to access the home 
>> directory /home/user2 and I cannot figure out the reason why.
>> This only happens when sending mails to multiple recipients.
>
>> I see the that lmtp complains that it doesn't have execute 
>> permissions. But I don't want to place execute permissions for
others
>> on the entire /home/* dir structure.
>
> as far as I remember there had been (or is) a bug in Dovecot, that 
> privilegues are not changed correctly when delivering to another user. 
> If that's the case, limit the number of recipients per LMTP message to 
> 1, see r= field in mailer definition in op.me.
>
> - -- Steffen Kaiser
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