On 01/09/2012 09:47 AM, Gémes Géza wrote:
Hi,
Comments in-line:
On 01/09/2012 07:38 AM, Gémes Géza wrote:
2012-01-08 10:13 keltezéssel, steve írta:
Hi
I have Samba 4 installed and working. I recently changed FQDN to dns
name hh3.hh3.site. It works OK and e.g. on a windows 7 box which
joined the domain, users can logon. But I have a mess in the keytab:
klist -k /etc/krb5.keytab
Keytab name: WRFILE:/etc/krb5.keytab
KVNO Principal
----
--------------------------------------------------------------------------
2 [email protected]
2 [email protected]
2 [email protected]
2 host/[email protected]
2 host/[email protected]
2 host/[email protected]
2 host/[email protected]
2 host/[email protected]
2 host/[email protected]
2 host/[email protected]
2 host/[email protected]
2 host/[email protected]
2 host/[email protected]
2 host/[email protected]
2 host/[email protected]
2 host/[email protected]
2 host/[email protected]
2 host/[email protected]
2 host/[email protected]
2 host/[email protected]
2 host/[email protected]
2 cifs/[email protected]
2 cifs/[email protected]
2 cifs/[email protected]
2 cifs/[email protected]
2 cifs/[email protected]
2 cifs/[email protected]
2 cifs/[email protected]
2 cifs/[email protected]
2 cifs/[email protected]
2 cifs/[email protected]
2 cifs/[email protected]
2 cifs/[email protected]
2 [email protected]
2 [email protected]
2 [email protected]
2 host/[email protected]
2 host/[email protected]
2 host/[email protected]
2 host/[email protected]
2 host/[email protected]
2 host/[email protected]
2 host/[email protected]
2 host/[email protected]
2 host/[email protected]
2 host/[email protected]
2 host/[email protected]
2 host/[email protected]
2 host/[email protected]
2 host/[email protected]
2 host/[email protected]
2 host/[email protected]
2 host/[email protected]
2 host/[email protected]
2 cifs/[email protected]
2 cifs/[email protected]
2 cifs/[email protected]
2 cifs/[email protected]
2 cifs/[email protected]
2 cifs/[email protected]
2 cifs/[email protected]
2 cifs/[email protected]
2 cifs/[email protected]
2 cifs/[email protected]
2 cifs/[email protected]
2 cifs/[email protected]
1 [email protected]
1 [email protected]
1 [email protected]
2 [email protected]
2 [email protected]
2 [email protected]
1 [email protected]
1 [email protected]
1 [email protected]
This all seems OK:
Kerberos: TGS-REQ [email protected] from ipv4:192.168.1.2:46585 for
[email protected] [canonicalize, renewable, forwardable]
Kerberos: TGS-REQ authtime: 2012-01-08T09:35:01 starttime:
2012-01-08T09:35:16 endtime: 2012-01-08T19:35:01 renew till:
2012-01-15T09:35:01
Kerberos: TGS-REQ [email protected] from ipv4:192.168.1.2:46577 for
host/[email protected] [canonicalize, renewable, forwardable]
Kerberos: TGS-REQ authtime: 2012-01-08T09:35:06 starttime:
2012-01-08T09:35:06 endtime: 2012-01-08T19:35:06 renew till:
2012-01-15T09:35:06
Got user=[] domain=[] workstation=[STEVE-PC] len1=1 len2=0
auth_check_password_send: Checking password for unmapped user
[]\[]@[STEVE-PC]
auth_check_password_send: mapped user is: [CACTUS]\[]@[STEVE-PC]
But I also get this:
Kerberos: TGS-REQ [email protected] from ipv4:192.168.1.2:46588 for
steve-pc$\@[email protected] [canonicalize, request-anonymous,
renewable, forwardable]
Kerberos: Bad request for constrained delegation
Kerberos: constrained delegation from [email protected]
([email protected]) as [email protected] to
steve-pc$\@[email protected] not allowed
Kerberos: Failed building TGS-REP to ipv4:192.168.1.2:46588
Which I think is due to the keytab
smb.conf contains:
[global]
server role = domain controller
workgroup = CACTUS
realm = hh3.site
netbios name = HH3
passdb backend = samba4
template shell = /bin/bash
So, 2 very newbie questions:
1. Is there anyway I can tidy up the keytab to see if removes that
error?
2. In the above example, steve-pc is a windows 7 client which is
joined to the domain called CACTUS. Why doesn't steve-pc$ appear in
the keytab listing?
/etc/krb5.keytab is a keytab you've created (e.g. with samba-tool
domain
exportkeytab /etc/krb5.keytab) it is not used by Samba4 in any way. If
you need a keytab for any service you run (e.g. nfs) I would
suggest to
extract a keytab only for the principal you've created for that
service.
E.g.:
samba-tool user create whateverserviceusername --random-password
samba-tool spn add previouslyusedusername servicename/hostname
samba-tool domain exportkeytab --principal=servicename/hostname
/path/to/the/keytab
Regards
Geza
Yeah, I can see I've not understood this. If I create a Samba 4 user
using samba-tool, he has to have a keytab to be able to login on a
Linux client.
NO NO NO
You need a keytab for service accounts (e.g. nfs) not for normal user
accounts (e.g. steve4), except when you need to run something
non-interactively (e.g. from crontab) which need access to a
kerberized service.
For user steve4 on domain HH3.SITE I did this:
samba-tool user add steve4
(the spn stuff you mention doesn't seem to be needed?)
samba-tool domain exportkeytab /etc/krb5.keytab --principal=steve4
You don't need the last step (see before).
OK, I'm understanding this a little more. So how can I remove steve4
from the keytab?
for nfs I did this:
samba-tool spn add nfs/HH3.SITE Administrator
samba-tool domain exportkeytab /etc/krb5.keytab --principal=nfs/HH3.SITE
That (the spn stuff) would work but it is BAD PRACTICE (it contradicts
the least privilege principle) you shouldn't give your nfs server the
right to administer your whole domain. You should create an account
for nfs (e.g. nfs-service-account or whatever) and for any kerberized
service/host in your domain. I now it is more work, but security-wise
that is the right solution.
I can see your point. So I do:
samba-tool user add nfs-service-account
samba-tool spn add nfs/HH3.SITE nfs-service account
samba-tool domain exportkeytab /etc/krb5.keytab --principal=nfs/HH3.SITE
But it's going to tell me that the nfs is already there no? So the
question is, how do I remove the nfs principal I created before as
Administrator?
steve4 can login to the Linux client and is placed in his nfs4
mounted /home directory (applause!). (The keytab above was before I
added nfs)
What I don't understand is why I need the keytab at all and how the
other stuff got in there.
Previously explained.
Just some side-notes:
Currently at our network we use OpenLDAP backed Samba3 servers (for
Windows domain control) with (the same) OpenLDAP backed Heimdal KDC,
for the various kerberized services (password protected webpages,
databases, OpenAFS, etc.). The Linux clients authenticate with
kerberos, get account from ldap. In the test network I've set up for
Samba4 I could reproduce the same with some different settings. The
important thing is: don't give services access to accounts with
sensitive rights! They don't need it.
Thanks for your patience.
Steve
Best Regards
Geza
Thanks Geza. I'm nearly there. The two questions above would be really
helpful.
Steve
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