Dovecot can't connect to openldap over starttls

[Tomas Habarta]

I've finally managed that running on Debian 8 test machine by commenting
	tls_ca_cert_file =
option from dovecot-ldap.conf, so only
	tls = yes
	tls_require_cert = demand

Not sure why is that as on my CentOS6 Dovecot works even with that
commented option. May be that CentOS and Debian uses different ldap
library or different versions or there's another peculiarity ...

Anyway, when tls_require_cert = demand is set, cite:
--
With a setting of demand the certificate is requested and a valid
certificate must be provided, otherwise the session is immediately
terminated.
--

As that option doesn't provide any source, it is taken from
/etc/ldap/ldap.conf on Debian and if it's missing there, Dovecot client
times out on validating provided certificate with

imap-login: Error: Timeout waiting for handshake from auth server.
imap-login: Disconnected: Auth process broken (disconnected before auth
was ready, waited 30 secs)



Tomas


On 03/18/2017 02:22 PM, info at gwarband.de wrote:
> The serverlog of openldap with loglevel "any":
> https://gwarband.de/openldap/openldap-connect.log
> Note: openldap waits 1 Minute before he says "TLS negotiation failure"
> after the connect.
> and dovecot says direct "Connect error"
> 
> I've also delete the TLSCipherSuite from openldap.
> 
> Tobias
> 
> Am 2017-03-18 14:01, schrieb Tomas Habarta:
>> Increase log level on server side as well to see what the server says...
>> You may remove anything in TLSCipherSuite for the purpose of testing too.
>>
>> Hopefully anyone knowing OpenLDAP internals could help you analyse it
>> more deeply.
>>
>> Tomas
>>
>> On 03/18/2017 01:31 PM, info at gwarband.de wrote:
>>> I've replicate the settings from ldapsearch to dovecot but no success.
>>> To the certificate:
>>> Yes it's a *.crt file but I have linked the *.pem file to it and dovecot
>>> has read access to that file.
>>>
>>> I have enabled the debugging in dovecot and have uploaded the output:
>>> https://gwarband.de/openldap/dovecot-connect.log
>>>
>>> And the other site with ldapsearch:
>>> https://gwarband.de/openldap/ldapsearch-connect.log
>>>
>>> I'm pretty sure that there is a problem with the sslhandshaking between
>>> openldap and dovecot, but I can't find the source of the problem.
>>>
>>> One of the steps in the sslhandshaking is not success but in the
>>> debugging output I can't find any line with a hit to it.
>>>
>>> Tobias
>>>
>>> Am 2017-03-18 12:30, schrieb Tomas Habarta:
>>>> Well, if ldapsearch works, try to replicate its settings for dovecot
>>>> client.
>>>> It's not obvious what settings ldapsearch uses, have a look at default
>>>> client settings in /etc/openldap/ldap.conf, there may be something
>>>> set a
>>>> slightly different way.
>>>> Also double check permissions for files used by dovecot, I mean mainly
>>>> the file listed for tls_ca_cert_file as dovecot may not have an access
>>>> for reading...
>>>>
>>>> I cannot see anything downright bad, just posted CA cert (which is ok,
>>>> tested) is *.crt and your config mentions *.pem but I consider it's the
>>>> same file.
>>>>
>>>> Finally, I would recommend to enable debug option for dovecot's client
>>>>     debug_level = -1 (which logs all available) in your
>>>> dovecot-ldap.conf
>>>> to see what the library reports and work further on that.
>>>> You can compare with output from ldapsearch by adding -d-1 switch to
>>>> it.
>>>>
>>>> Hard to tell more at the moment.
>>>>
>>>>
>>>> Tomas
>>>>
>>>> On 03/18/2017 09:41 AM, info at gwarband.de wrote:
>>>>> Hello,
>>>>>
>>>>> I have also installed LE certs.
>>>>> But nothing helps, I have double-checking all certs.
>>>>>
>>>>> ldapsearch with -ZZ works see:
>>>>> https://gwarband.de/openldap/ldapsearch.log
>>>>>
>>>>> I have also uploaded the TLSCACertificateFile, maybe I have a
>>>>> failure in
>>>>> the merge of the two fiels:
>>>>> https://gwarband.de/openldap/LetsEncrypt.crt
>>>>>
>>>>> And also I have uploaded my complete openldap configuration:
>>>>> https://gwarband.de/openldap/openldap.conf
>>>>>
>>>>> All other components can work and communicate with my openldap server.
>>>>> The components are postfix, openxchange, apache (phpldapadmin).
>>>>>
>>>>> My installated software is:
>>>>> Debian 8
>>>>> OpenLDAP 2.4.40
>>>>> Dovecot 2.2.13
>>>>>
>>>>> I hope you can find the issue.
>>>>>
>>>>> Thanks,
>>>>> Tobias
>>>>>
>>>>> Am 2017-03-17 22:48, schrieb Tomas Habarta:
>>>>>> Hi,
>>>>>>
>>>>>> been running Dovecot 2.2.27 against OpenLDAP 2.4.40 normally over the
>>>>>> unix socket on the same machine, but tried over inet with STARTTLS
>>>>>> and
>>>>>> it's working ok...
>>>>>>
>>>>>> I would suggest double-checking key/certs setup on OpenLDAP side; for
>>>>>> the test I have used LE certs, utilizing following cn=config
>>>>>> attributes:
>>>>>>
>>>>>> olcTLSCertificateKeyFile    contains private key
>>>>>> olcTLSCertificateFile        contains certificate
>>>>>> olcTLSCACertificateFile        contains both certs (DST Root CA X3
>>>>>>                 and Let's Encrypt Authority X3)
>>>>>>
>>>>>> and used the same CA file in Dovecot's tls_ca_cert_file
>>>>>>
>>>>>> Is ldapsearch working ok (-ZZ) and only Dovecot has troubles or ... ?
>>>>>>
>>>>>>
>>>>>>
>>>>>> Hope that helps, good luck ;)
>>>>>> Tomas
>>>>>>
>>>>>>
>>>>>> On 03/17/2017 04:27 PM, info at gwarband.de wrote:
>>>>>>> Hello guys,
>>>>>>>
>>>>>>> actually I'm trying to configure dovecot to access openldap for
>>>>>>> passwordcheck.
>>>>>>> My openldap is only allow access over "secure ldap".
>>>>>>> The dovecot can communicate with the openldap server but there is
>>>>>>> maybe
>>>>>>> a failure in the sslhandshake.
>>>>>>> Additional information you can find in the logs or in the dump
>>>>>>> below.
>>>>>>> Also I have my ldap config from dovecot in the links below.
>>>>>>>
>>>>>>> I have already created an bug reporting in the system of openldap
>>>>>>> but
>>>>>>> the answer was to get support from her.
>>>>>>>
>>>>>>> All datalinks:
>>>>>>> https://gwarband.de/openldap/dovecot.log
>>>>>>> https://gwarband.de/openldap/dovecot-ldap.conf
>>>>>>> https://gwarband.de/openldap/openldap.log
>>>>>>> https://gwarband.de/openldap/trace.dump
>>>>>>>
>>>>>>> The bugreportinglink from openldap:
>>>>>>> http://www.openldap.org/its/index.cgi/Incoming?id=8615
>>>>>>>
>>>>>>> I hope you can help me.
>>>>>>>
>>>>>>> Regards.
>>>>>>> Tobias Warband

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