Kerberos authentication by PAM againts AD Windows 2003 Server domain

[Martin Schweizer]

Hello

My goal is to authenticate my Cyrus Imapd users against Windos 2003
Active Directory with Kerberos . I have the following setup:

Kerberos5 client
===========
FreeBSD acsvfbsd06.domain.tld 7.2-RELEASE FreeBSD 7.2-RELEASE

/etc/krb.conf:
[libdefaults]

       default_realm = domain.tld

       default_etypes_des = des-cbc-md5

[realms]
   ACUTRONIC.CH = {
       kdc = tcp/acsv3k04.domain.tld:88
   }

[logging]
                kdc = SYSLOG:INFO:AUTH
               admin_server = SYSLOG:INFO:AUTH
               default = SYSLOG:INFO:AUTH

/etc/krb5.keytab (ktutil list output):
For the keytab file I followed:
http://technet.microsoft.com/en-us/library/bb742433.aspx

FILE:/etc/krb5.keytab:

Vno  Type         Principal
 1  des-cbc-md5  host/acsvfbsd06.domain.tld at DOMAIN.TLD

I get tickets if I use kinit user:
acsvfbsd06# kinit user
martin at DOMAIN.TLD's Password:
kinit: NOTICE: ticket renewable lifetime is 1 week

klist:
Credentials cache: FILE:/tmp/krb5cc_0
       Principal: user at DOMAIN.TLD

 Issued           Expires          Principal
Jul 31 17:58:09  Aug  1 03:57:44  krbtgt/DOMAIN.TLD at DOMAIN.TLD

I can no more use ldapsearch as follows:

acsvfbsd06# ldapsearch -v -LLL -b
"OU=Mitgliedsserver,OU=ACH,DC=Domain,DC=tld" -h acsv3k04.domain.tld description

Which in the past worked. And really I did not change anything.

I checked also the DNS and Kerberos communication by tcpdump without any 
strange issues. As the DNS server I use is the KDC server (all the DNS 
Kerberos erntries are correct).

My PAM configurations is:
/etc/pam.d/imap:
auth            required      pam_krb5.so     try_first_pass debug

I tried with testsaslautd -u username - password different combinations of 
user names and passwords. As expected the wrong ones would be denied. But I 
get no PAM_SUCCESS for the correct ones, with one exception: If I use 
sufficient as PAM option then all username and password combinations (wrong or 
not) would be accepted! With the option required (and the others) I see in 
/var/log/auth.log:

Aug 30 18:27:04 acsvfbsd06 saslauthd[9188]: rel_accept_lock : released accept 
lock
Aug 30 18:27:04 acsvfbsd06 saslauthd[9188]: pam_krb5: verify_krb_v5_tgt(): 
krb5_rd_req(): Key table entry not found
Aug 30 18:27:04 acsvfbsd06 saslauthd[9188]: DEBUG: auth_pam: pam_authenticate 
failed: authentication error
Aug 30 18:27:04 acsvfbsd06 saslauthd[9188]: do_auth         : auth failure: 
[user=martin] [service=imap] [realm=] [mech=pam] [reason=PAM auth error]
Aug 30 18:27:04 acsvfbsd06 saslauthd[9188]: get_accept_lock : acquired accept 
lock

I read FreeBSDs PAM documentation backwards and forwards but did not find any 
clue. Also I did not find any hints about the debugging for PAM problems.

So I have now no more ideas where I can check. Any hints are welcome.

Kind regards,

-- 

Martin Schweizer
<office at pc-service.ch>

PC-Service M. Schweizer GmbH; Bannholzstrasse 6; CH-8608 Bubikon
Tel. +41 55 243 30 00; Fax: +41 55 243 33 22; http://www.pc-service.ch;
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