krb5 mount with large group membership

krb5 mount with large group membership

[Richard Smits]

Hello list,

I am running into a problem. Perhaps someone understands what is 
happening here. I will explain.

I have a Redhat 5.4 client that is accessing a nfs export on a NFS 
server. (Redhat 6.1)

Our KDC is a Windows AD.

The client is using samba-winbind. If a user is a member of 23 groups or 
lower, I can access the export. If a user is a member of more groups, 
the mount fails with a "Permission denied"

mount /data
-bash-3.2$ cd /data
-bash: cd: /data: Permission denied

Thew odd thing is if I try a mount to our Netapp filer with also a krb5 
export, there is no problem.

This has to do something with the ticket size in combination with 
memberships to a large number of groups.

So what must i do to get this Redhat server working with this setup ? It 
seems that Netapp did something to get this working ?

Does this sound familiar to anyone, or should i provide more information ?

Versions server side :
nfs-utils-1.2.3-7
krb5-workstation-1.9-9

Greetings ... Richard Smits

RE: krb5 mount with large group membership

[Assarsson, Emil]

Hi,

Your ticket is probably oversized for the NFS server.
Try set NO_AUTH_DATA_REQUIRED (google msn) on the object holding the servers SPN.

--
Emil Assarsson

> -----Original Message-----
> From: linux-nfs-owner@vger.kernel.org [mailto:linux-nfs-owner@vger.kernel.org]
> On Behalf Of Richard Smits
> Sent: torsdag den 14 juli 2011 11:30
> To: linux-nfs@vger.kernel.org
> Subject: krb5 mount with large group membership
> 
> Hello list,
> 
> I am running into a problem. Perhaps someone understands what is
> happening here. I will explain.
> 
> I have a Redhat 5.4 client that is accessing a nfs export on a NFS
> server. (Redhat 6.1)
> 
> Our KDC is a Windows AD.
> 
> The client is using samba-winbind. If a user is a member of 23 groups or
> lower, I can access the export. If a user is a member of more groups,
> the mount fails with a "Permission denied"
> 
> mount /data
> -bash-3.2$ cd /data
> -bash: cd: /data: Permission denied
> 
> Thew odd thing is if I try a mount to our Netapp filer with also a krb5
> export, there is no problem.
> 
> This has to do something with the ticket size in combination with
> memberships to a large number of groups.
> 
> So what must i do to get this Redhat server working with this setup ? It
> seems that Netapp did something to get this working ?
> 
> Does this sound familiar to anyone, or should i provide more information ?
> 
> Versions server side :
> nfs-utils-1.2.3-7
> krb5-workstation-1.9-9
> 
> Greetings ... Richard Smits
> --
> To unsubscribe from this list: send the line "unsubscribe linux-nfs" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html

Re: krb5 mount with large group membership

[Richard Smits]

Hi,

Good tip. Thank you.

note : If I check the "Do not require Kerberos preauthentication" in the 
AD on my testaccount, it works...

So now i have to look what else this breaks.

Greetings .. Richard

On 07/14/2011 01:14 PM, Assarsson, Emil wrote:
> Hi,
>
> Your ticket is probably oversized for the NFS server.
> Try set NO_AUTH_DATA_REQUIRED (google msn) on the object holding the servers SPN.
>
> --
> Emil Assarsson
>
>> -----Original Message-----
>> From: linux-nfs-owner@vger.kernel.org [mailto:linux-nfs-owner@vger.kernel.org]
>> On Behalf Of Richard Smits
>> Sent: torsdag den 14 juli 2011 11:30
>> To: linux-nfs@vger.kernel.org
>> Subject: krb5 mount with large group membership
>>
>> Hello list,
>>
>> I am running into a problem. Perhaps someone understands what is
>> happening here. I will explain.
>>
>> I have a Redhat 5.4 client that is accessing a nfs export on a NFS
>> server. (Redhat 6.1)
>>
>> Our KDC is a Windows AD.
>>
>> The client is using samba-winbind. If a user is a member of 23 groups or
>> lower, I can access the export. If a user is a member of more groups,
>> the mount fails with a "Permission denied"
>>
>> mount /data
>> -bash-3.2$ cd /data
>> -bash: cd: /data: Permission denied
>>
>> Thew odd thing is if I try a mount to our Netapp filer with also a krb5
>> export, there is no problem.
>>
>> This has to do something with the ticket size in combination with
>> memberships to a large number of groups.
>>
>> So what must i do to get this Redhat server working with this setup ? It
>> seems that Netapp did something to get this working ?
>>
>> Does this sound familiar to anyone, or should i provide more information ?
>>
>> Versions server side :
>> nfs-utils-1.2.3-7
>> krb5-workstation-1.9-9
>>
>> Greetings ... Richard Smits
>> --
>> To unsubscribe from this list: send the line "unsubscribe linux-nfs" in
>> the body of a message to majordomo@vger.kernel.org
>> More majordomo info at  http://vger.kernel.org/majordomo-info.html

RE: krb5 mount with large group membership

[Assarsson, Emil]

Hi,

Pre-authentication errors:

Try to limit the /etc/krb5.conf to use the 3 closest KDC's only.
I'm using winbind and link /etc/krb5.conf to /var/run/samba/smb_krb5/krb5.conf.* (there should be a "locate" module for mit-krb5 but lucid doesn't provide it).

It can be solved with do not require but I think it's better to solve the real problem.
--
Emil Assarsson

> -----Original Message-----
> From: Richard Smits [mailto:R.Smits@tudelft.nl]
> Sent: torsdag den 14 juli 2011 15:03
> To: linux-nfs@vger.kernel.org
> Cc: Assarsson, Emil
> Subject: Re: krb5 mount with large group membership
> 
> Hi,
> 
> Good tip. Thank you.
> 
> note : If I check the "Do not require Kerberos preauthentication" in the
> AD on my testaccount, it works...
> 
> So now i have to look what else this breaks.
> 
> Greetings .. Richard
> 
> On 07/14/2011 01:14 PM, Assarsson, Emil wrote:
> > Hi,
> >
> > Your ticket is probably oversized for the NFS server.
> > Try set NO_AUTH_DATA_REQUIRED (google msn) on the object holding the servers
> SPN.
> >
> > --
> > Emil Assarsson
> >
> >> -----Original Message-----
> >> From: linux-nfs-owner@vger.kernel.org [mailto:linux-nfs-
> owner@vger.kernel.org]
> >> On Behalf Of Richard Smits
> >> Sent: torsdag den 14 juli 2011 11:30
> >> To: linux-nfs@vger.kernel.org
> >> Subject: krb5 mount with large group membership
> >>
> >> Hello list,
> >>
> >> I am running into a problem. Perhaps someone understands what is
> >> happening here. I will explain.
> >>
> >> I have a Redhat 5.4 client that is accessing a nfs export on a NFS
> >> server. (Redhat 6.1)
> >>
> >> Our KDC is a Windows AD.
> >>
> >> The client is using samba-winbind. If a user is a member of 23 groups or
> >> lower, I can access the export. If a user is a member of more groups,
> >> the mount fails with a "Permission denied"
> >>
> >> mount /data
> >> -bash-3.2$ cd /data
> >> -bash: cd: /data: Permission denied
> >>
> >> Thew odd thing is if I try a mount to our Netapp filer with also a krb5
> >> export, there is no problem.
> >>
> >> This has to do something with the ticket size in combination with
> >> memberships to a large number of groups.
> >>
> >> So what must i do to get this Redhat server working with this setup ? It
> >> seems that Netapp did something to get this working ?
> >>
> >> Does this sound familiar to anyone, or should i provide more information ?
> >>
> >> Versions server side :
> >> nfs-utils-1.2.3-7
> >> krb5-workstation-1.9-9
> >>
> >> Greetings ... Richard Smits
> >> --
> >> To unsubscribe from this list: send the line "unsubscribe linux-nfs" in
> >> the body of a message to majordomo@vger.kernel.org
> >> More majordomo info at  http://vger.kernel.org/majordomo-info.html

Re: krb5 mount with large group membership

[J. Bruce Fields]

On Thu, Jul 14, 2011 at 01:14:07PM +0200, Assarsson, Emil wrote:
> Hi,
> 
> Your ticket is probably oversized for the NFS server.
> Try set NO_AUTH_DATA_REQUIRED (google msn) on the object holding the servers SPN.

The server has trouble with init_sec_context tokens that are longer than
a few k--I'd have to check the exact limit.  (I wonder how big this one
is?)

--b.

> 
> --
> Emil Assarsson
> 
> > -----Original Message-----
> > From: linux-nfs-owner@vger.kernel.org [mailto:linux-nfs-owner@vger.kernel.org]
> > On Behalf Of Richard Smits
> > Sent: torsdag den 14 juli 2011 11:30
> > To: linux-nfs@vger.kernel.org
> > Subject: krb5 mount with large group membership
> > 
> > Hello list,
> > 
> > I am running into a problem. Perhaps someone understands what is
> > happening here. I will explain.
> > 
> > I have a Redhat 5.4 client that is accessing a nfs export on a NFS
> > server. (Redhat 6.1)
> > 
> > Our KDC is a Windows AD.
> > 
> > The client is using samba-winbind. If a user is a member of 23 groups or
> > lower, I can access the export. If a user is a member of more groups,
> > the mount fails with a "Permission denied"
> > 
> > mount /data
> > -bash-3.2$ cd /data
> > -bash: cd: /data: Permission denied
> > 
> > Thew odd thing is if I try a mount to our Netapp filer with also a krb5
> > export, there is no problem.
> > 
> > This has to do something with the ticket size in combination with
> > memberships to a large number of groups.
> > 
> > So what must i do to get this Redhat server working with this setup ? It
> > seems that Netapp did something to get this working ?
> > 
> > Does this sound familiar to anyone, or should i provide more information ?
> > 
> > Versions server side :
> > nfs-utils-1.2.3-7
> > krb5-workstation-1.9-9
> > 
> > Greetings ... Richard Smits
> > --
> > To unsubscribe from this list: send the line "unsubscribe linux-nfs" in
> > the body of a message to majordomo@vger.kernel.org
> > More majordomo info at  http://vger.kernel.org/majordomo-info.html
> --
> To unsubscribe from this list: send the line "unsubscribe linux-nfs" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html