Re: Kerberos Authentication Failing for Windows 7+ with BH gss_accept_sec_context() failed

["Pedro Lobo" <palobo@xxxxxxxxx>]

Hi Markus,

I used msktutil to create the keytab.

msktutil -c -s HTTP/proxy01tst.fake.net -h proxy01tst.fake.net -k /etc/squid3/PROXY.keytab --computer-name proxy01-tst --upn HTTP/proxy01tst.fake.net --server srv01.fake.net --verbose

Output of klist -ekt:

   2 10/24/2014 22:59:50 proxy01-tst$@FAKE.NET (arcfour-hmac)
   2 10/24/2014 22:59:50 proxy01-tst$@FAKE.NET (aes128-cts-hmac-sha1-96)
   2 10/24/2014 22:59:50 proxy01-tst$@FAKE.NET (aes256-cts-hmac-sha1-96)
   2 10/24/2014 22:59:50 HTTP/proxy01tst.FAKE.net@xxxxxxxx (arcfour-hmac)
   2 10/24/2014 22:59:50 HTTP/proxy01tst.FAKE.net@xxxxxxxx (aes128-cts-hmac-sha1-96)
   2 10/24/2014 22:59:50 HTTP/proxy01tst.FAKE.net@xxxxxxxx (aes256-cts-hmac-sha1-96)
   2 10/24/2014 22:59:50 host/proxy01tst.FAKE.net@xxxxxxxx (arcfour-hmac)
   2 10/24/2014 22:59:50 host/proxy01tst.FAKE.net@xxxxxxxx (aes128-cts-hmac-sha1-96)
   2 10/24/2014 22:59:50 host/proxy01tst.FAKE.net@xxxxxxxx (aes256-cts-hmac-sha1-96)

Yep, using MIT Kerberos

Thanks in advance for any help.

Cheers,
Pedro

On 25 Oct 2014, at 1:26, Markus Moeller wrote:

Hi Pedro,

How did you create your keytab ? What does klist –ekt <squid.keytab> show ( I assume you use MIT Kerberos) ?

Markus

"Pedro Lobo" palobo@xxxxxxxxx wrote in message news:40E1E0E7-50C6-4117-94AA-50B06573430A@xxxxxxxxx...
Hi Squid Gurus,

I'm at my wit's end and in dire need of some squid expertise.

We've got a production environment with a couple of squid 2.7 servers using NTLM and basic authentication. Recently though, we decided to upgrade and I'm now setting up squid 3.3 with Kerberos and NTLM Fallback. I've followed just about every guide I could find and in my testing environment, things were working great. Now that I've hooked it up to the main domain, things are awry.

If I use a machine that's not part of the domain, NTLM kicks in and I can surf the web fine. If I use a Windows XP or Windows Server 2003, kerberos works just fine, however, if I use a machine Windows 7, 8 or 2008 server, I keep getting a popup asking me to authenticate and even then, it's and endless loop until it fails. My cache.log is littered with:

negotiate_kerberos_auth.cc(200): pid=1607 :2014/10/24 23:03:01| negotiate_kerberos_auth: ERROR: gss_accept_sec_context() failed: Unspecified GSS failure. Minor code may provide more information.
2014/10/24 23:03:01| ERROR: Negotiate Authentication validating user. Error returned 'BH gss_accept_sec_context() failed: Unspecified GSS failure. Minor code may provide more information. '
The odd thing, is that this has worked before. Help me Obi Wan... You're my only hope! :)

Current Setup
Squid 3.3 running on Ubuntu 14.04 server. It's connected to a 2003 server with function level 2000 (I know, we're trying to fase out the older servers).

krb5.conf

[libdefaults]
default_realm = FAKE.NET
dns_lookup_kdc = yes
dns_lookup_realm = yes
ticket_lifetime = 24h
default_keytab_name = /etc/squid3/PROXY.keytab

; for Windows 2003
default_tgs_enctypes = rc4-hmac des-cbc-crc des-cbc-md5
default_tkt_enctypes = rc4-hmac des-cbc-crc des-cbc-md5
permitted_enctypes = rc4-hmac des-cbc-crc des-cbc-md5

[realms]
FAKE.NET = {
kdc = srv01.fake.net
kdc = srv02.fake.net
kdc = srv03.fake.net
admin_server = srv01.fake.net
default_domain = fake.net
}

[domain_realm]
.fake.net = FAKE.NET
fake.net = FAKE.NET

[logging]
kdc = FILE:/var/log/kdc.log
admin_server = FILE:/var/log/kadmin.log
default = FILE:/var/log/krb5lib.log
squid.conf

auth_param negotiate program /usr/lib/squid3/negotiate_kerberos_auth -d -r -s HTTP/proxy01tst.fake.net
auth_param negotiate children 20 startup=0 idle=1
auth_param negotiate keep_alive off

auth_param ntlm program /usr/bin/ntlm_auth --diagnostics --helper-protocol=squid-2.5-ntlmssp --domain=FAKE.NET
auth_param ntlm children 10
auth_param ntlm keep_alive off
Cheers,
Pedro

Cumprimentos
Pedro Lobo
Solutions Architect | System Engineer

pedro.lobo@xxxxxxxxxxxx
Tlm.: +351 939 528 827 | Tel.: +351 214 127 314

Claranet Portugal
Ed. Parque Expo
Av. D. João II, 1.07-2.1, 4º Piso
1998-014 Lisboa
www.claranet.pt

Empresa certificada ISO 9001, ISO 20000 e ISO 27001

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Cumprimentos
Pedro Lobo
Solutions Architect | System Engineer

pedro.lobo@xxxxxxxxxxxx
Tlm.: +351 939 528 827 | Tel.: +351 214 127 314

Claranet Portugal
Ed. Parque Expo
Av. D. João II, 1.07-2.1, 4º Piso
1998-014 Lisboa
www.claranet.pt

Empresa certificada ISO 9001, ISO 20000 e ISO 27001