[EXT] 'HANDLE_AUTHDATA' error when trying to setup Kerberos trust between AD and FreeIPA

[Dmitri Pal]

On Mon, Jun 15, 2020 at 9:49 PM Robert Sturrock <rns at unimelb.edu.au> wrote:

> Hi Dmitri,
>
> Sorry - I did not give all the background in the interests of brevity.  We
> do not want to establish a full trust between AD and IPA (at this stage).
> This is for a number of reasons, but is primarily a reluctance to bring a
> very large and entirely irrelevant set of AD groups across to IPA-enrolled
> hosts.
>
> The IPA installation is running in a ‘winsync’ arrangement with AD, but as
> a convenience for the users it would be useful if a TGT from AD were
> sufficient to access services in the IPA realm, to save them having to
> ‘kinit' to another kerberos realm.
>
> So I’m interested in establishing a trust at the Kerberos level only.  We
> have done this successfully between a legacy MIT kerberos service and IPA,
> so I hoped we could also set one up between AD and IPA, before running into
> the error I described.
>
> Any clues as to what the reason for the ‘HANDLE_AUTHDATA’ error might be?
>

Thanks for the explanation.
I suspect that IdM does not know anything about the principal you are using
and thus fails to fetch/process authorization data that it needs to put
into the ticket.
But this is my pure speculation based on a general understanding of the IPA
architecture.
You might get better help on the freeipa-users list but frankly I am not
sure anyone tried or would recommend such a setup there. You are crossing
uncharted territory for sure.

Thanks
Dmitri



>
> Regards,
>
> Robert.
>
>
> > On 15 Jun 2020, at 11:00 pm, Dmitri Pal <dpal at redhat.com> wrote:
> >
> >
> >
> > UoM notice: External email. Be cautious of links, attachments, or
> impersonation attempts.
> > On Mon, Jun 15, 2020 at 2:39 AM Robert Sturrock <rns at unimelb.edu.au>
> wrote:
> > Hi All,
> >
> > I’m trying to create a (one-way) Kerberos trust between AD and a FreeIPA
> installation, such that user TGTs from AD can be used to access resources
> in the IPA realm.
> >
> > I followed some (non-IPA related) steps for setting up Kerberos trusts
> between AD and MIT Kerberos - essentially creating a common TGT principal
> in both systems with a common password.  This works to a point (ie. I can
> get the TGT for IPA using the AD TGT), but when I try to fetch a service
> ticket in the IPA domain I get a ‘HANDLE_AUTHDATA’ error.
> >
> > Was there any reason not to follow IPA steps for setting trusts?
> > They are very straightforward.
> >
> https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/8/html/installing_identity_management/installing-trust-between-idm-and-ad_installing-identity-management
> >
> >
> >
> > Here is what I’m seeing:
> >
> >  (AD domain = ‘STAFF.LOCALREALM'; IPA domain = ‘PALLAS.LOCALREALM')
> >
> >  # Get AD TGT:
> >  Password for rns at STAFF.LOCALREALM: XXXXXXXXX
> >
> >  $ klist
> >  Ticket cache: KEYRING:persistent:10846:10846
> >  Default principal: rns at STAFF.LOCALREALM
> >
> >  Valid starting     Expires            Service principal
> >  11/06/20 13:34:19  11/06/20 23:34:19
> krbtgt/STAFF.LOCALREALM at STAFF.LOCALREALM
> >          renew until 12/06/20 13:34:18
> >
> >  # Use AD TGT to get an IPA TGT:
> >  $ kvno krbtgt/PALLAS.LOCALREALM at STAFF.LOCALREALM
> >  krbtgt/PALLAS.LOCALREALM at STAFF.LOCALREALM: kvno = 0
> >
> >  $ klist
> >  Ticket cache: KEYRING:persistent:10846:10846
> >  Default principal: rns at STAFF.LOCALREALM
> >
> >  Valid starting     Expires            Service principal
> >  11/06/20 13:34:24  11/06/20 23:34:19
> krbtgt/PALLAS.LOCALREALM at STAFF.LOCALREALM
> >          renew until 12/06/20 13:34:18
> >  11/06/20 13:34:19  11/06/20 23:34:19
> krbtgt/STAFF.LOCALREALM at STAFF.LOCALREALM
> >          renew until 12/06/20 13:34:18
> >
> >  # Try to fetch an IPA service ticket:
> >  $ kvno host/palladium1.localdomain at PALLAS.LOCALREALM
> >  kvno: KDC returned error string: HANDLE_AUTHDATA while getting
> credentials for host/palladium1.localdomain at PALLAS.LOCALREALM
> >
> > Can anyone provide some idea as to what’s going on here and how I
> resolve this?  I don’t really know what ‘HANDLE_AUTHDATA’ indicates and I’m
> not able to find a lot of documentation explaining this.
> >
> > Thanks!
> >
> > Robert.
> >
> > ________________________________________________
> > Kerberos mailing list           Kerberos at mit.edu
> > https://mailman.mit.edu/mailman/listinfo/kerberos
> >
> >
> > --
> > Thank you,
> > Dmitri Pal
> > Director, Software Engineering
> > Red Hat Enterprise Linux Platform Security and Identity Management
> > dpal at redhat.com
> >
>
>

-- 

Thank you,
Dmitri Pal

Director, Software Engineering
Red Hat Enterprise Linux Platform Security and Identity Management
dpal at redhat.com
 <https://red.ht/sig>