s3 member server to s4 kerberos trouble

Lukasz Zalewski lukas at dcs.qmul.ac.uk
Sat Jun 12 11:24:58 MDT 2010

On 12/06/2010 18:19, Lukasz Zalewski wrote:
> On 11/06/2010 21:02, Matthieu Patou wrote:
> Hi Matthieu,
>> Hello Lukaz,
>> To my mind according to your log the pb is that w7 present an AES
>> encrypted ticket, and s3, didn't support for this version, AES.
>> In order for s4 to provide AES ticket, you should have raised to level
>> 2008 your domain, because by default we do provision with a 2003
>> functional level.
>> Is it the case ?
> I have provisioned using --function-level=2008
>> Even win this case we should be able to sort out differences in capacity.
>> If I trust your log it _seems_ that your s3 pretend to support encoding
>> that it in fact didn't support :
>> ipv4: for
>> Kerberos: No preauth found, returning PREAUTH-REQUIRED --
>> ipv4: for
>> Kerberos: Client sent patypes: encrypted-timestamp
>> Kerberos: Looking for PKINIT pa-data -- ORINOCO$@STUDENT.EECS.QMUL.AC.UK
>> Kerberos: Looking for ENC-TS pa-data -- ORINOCO$@STUDENT.EECS.QMUL.AC.UK
>> Kerberos: ENC-TS Pre-authentication succeeded --
>> ORINOCO$@STUDENT.EECS.QMUL.AC.UK using aes256-cts-hmac-sha1-96
>> Kerberos: AS-REQ authtime: 2010-06-11T09:59:30 starttime: unset endtime:
>> 2010-06-12T09:59:33 renew till: unset
>> Kerberos: Client supported enctypes: aes256-cts-hmac-sha1-96,
>> arcfour-hmac-md5, des3-cbc-sha1, des-cbc-crc, des-cbc-md5, using
>> aes256-cts-hmac-sha1-96/aes256-cts-hmac-sha1-96
>> Can you confirm that ORINOCO is your s3 server and that is
>> its ip.
> That is correct for both
>> Andrew: if it is so I have the impression that something wrong: either
>> from s4 side because it thinks that the client support that it is not
>> announcing as supported, either it's s3 which announce encoding that it
>> fact it didn't support.
>> In any case even in if s3 announce wrong encoding when requesting
>> ticket, we should use msDS-SupportedEncryptionTypes when requested for a
>> ticket for a given principal (ie. cifs/server at REALM) to decide in which
>> encoding we return the ticket to the requester so that it can be
>> understood by requester and and requested principal. Looking at the code
>> I didn't saw much lookup to this attribute so I wonder how do we decide
>> which encoding the requested principal support.
> The workaround that i found (for now) is to limit kerberos encription
> types to those suppoted by s3 (removing AES ones). Downside is that all
> tickets issued are Arcfour ones from then on - but the shares can be
> mounted
Forgot to att that this workaround was iplemented using group policy 
that was applied to w7 client
>> Lukasz, a full trace from login and restart of s3 would be very useful
>> to see what's happenning.
>> If you can provide me the keytab of the domain it would be super (but it
>> means that I have somehow enough information to pretend to be you, your
>> dc or your server, so you'd better use a generic password for admin and
>> be ready to reprovision the domain).
> i can create a test domain that is thrashable ;) (As this one is too). I
> wont be able to do this over this weekend though.
>> Matthieu.
>> On 11/06/2010 13:17, Lukasz Zalewski wrote:
>>> Hi!
>>> The Samba 3 i have used is 3.3.8 running on centos 5.5 (i have tried
>>> samba 3.4.7 on Fedora 12 whiche exhibited same behaviour)
>>> I can join S3 machine to the s4 domain without any problems (well
>>> there is a DNS update failed). I can also mount any share from
>>> non-domain machines (it being XP or 7) without any issies. The
>>> problems start when i log in to the s4 domain - my homeDrive is
>>> specified as \\s3memberserver\username.
>>> Also whne i try to manually map the drive the authentication box pops
>>> up.
>>> Attached are s4 d10 log and memberserver client's d10 logs. Please let
>>> me know if you need anything else
>>> Regards
>>> Luk

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