[squid-users] Squid3 Kerberos Auth works but does not update the users group membership in the winbind cache of samba as for examle ntlm_auth does

[Heine, Enrico]

Hello together,

My Issue is the following: 

Using Squid3 with Kerberos Auth works just fine but does not update the users group membership in the winbind cache of samba as for examle ntlm_auth does.

So when using /usr/lib/squid3/negotiate_kerberos_auth for Kerberos, the auth works, but group memberships for my user as example are never updated, when I comment this auth helper then it gets updated because then I use ntlm_auth for ntlmssp
So if I have a new group eg: My_Test , then I can check this like this: 

wbinfo -n My_Test -> returns SID of My_Test
wbinfo -Y SID -> returns mapped GID
wbinfo -r myuser | grep GID -> GID is not listed!!

getent group My_Test -> returns: myuser is member of that group! So just in my account "myuser" it is not listed (wbinfo -r myuser | grep GID -> GID is not listed!!) but ext_wbinfo_group_acl is checking my group membership based on the commands listed above.

Commenting Kerberos auth in the squid conf, so that only ntlm_auth is used and requesting one website to be sure to have done an auth, works. So then the GID is listed in the output of wbinfo -r myuser

How can I ensure that my memberships are getting updated using /usr/lib/squid3/negotiate_kerberos_auth as it does work with ntlm_user? Or is there another auth helper that can be used for Kerberos that is doing what ntlm_user does automatically after an successfull authentication?

My Squid Config for Auth Helpers looks like this:

######################################################### Kerberos #########################################################
#auth_param negotiate program /usr/lib/squid3/negotiate_kerberos_auth -r -s HTTP/myserver.MYDOMAIN at MYDOMAIN
#auth_param negotiate children 300
#auth_param negotiate keep_alive on

######################################################### NTLM #########################################################
auth_param ntlm program /usr/bin/ntlm_auth --helper-protocol=squid-2.5-ntlmssp
auth_param ntlm children 50
auth_param ntlm keep_alive off

######################################################### BASIC #########################################################
auth_param basic program /usr/bin/ntlm_auth --helper-protocol=squid-2.5-basic
auth_param basic children 50
auth_param basic credentialsttl 2 hours
auth_param basic realm Windows Authentication required
auth_param basic casesensitive off

Also I am using the following to check group memberships, which is working fine !! with all auth helpers !! and it is much faster than the slow Kerberos group check, I assume that this helper is updating automatically the winbind group cache, which is the reason that the group itself is beeing recognized and I am also a member of that group when I check that specific group via getent group My_Test

external_acl_type nt_group ttl=60 children-max=300 children-startup=50 %LOGIN /usr/lib/squid3/ext_wbinfo_group_acl -K

Software Versions used:
- Squid Cache: Version 3.4.8
- Samba & winbindd Version 4.1.17-Debian
- Distri: Debian Jessie


-- 
-- 
Best regards,
Enrico Heine

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