Copy: [email protected] ([email protected])

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?

Regards,

Robert.

On 15 Jun 2020, at 11:00 pm, Dmitri Pal <[email protected]> wrote:

UoM notice: External email. Be cautious of links, attachments, or impersonation attempts.
On Mon, Jun 15, 2020 at 2:39 AM Robert Sturrock <[email protected]> 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 [email protected]EALM: XXXXXXXXX

$ klist
Ticket cache: KEYRING:persistent:10846:10846
Default principal: [email protected]EALM

Valid starting Expires Service principal
11/06/20 13:34:19 11/06/20 23:34:19 krbtgt/[email protected]EALM
renew until 12/06/20 13:34:18

# Use AD TGT to get an IPA TGT:
$ kvno krbtgt/[email protected]EALM
krbtgt/[email protected]EALM: kvno = 0

$ klist
Ticket cache: KEYRING:persistent:10846:10846
Default principal: [email protected]EALM

Valid starting Expires Service principal
11/06/20 13:34:24 11/06/20 23:34:19 krbtgt/[email protected]EALM
renew until 12/06/20 13:34:18
11/06/20 13:34:19 11/06/20 23:34:19 krbtgt/[email protected]EALM
renew until 12/06/20 13:34:18

# Try to fetch an IPA service ticket:
$ kvno host/[email protected]EALM
kvno: KDC returned error string: HANDLE_AUTHDATA while getting credentials for host/[email protected]EALM

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 [email protected] https://mailman.mit.edu/mailman/listinfo/kerberos

--
Thank you,
Dmitri Pal
Director, Software Engineering
Red Hat Enterprise Linux Platform Security and Identity Management [email protected]

--- SoupGate-Win32 v1.05
* Origin: fsxNet Usenet Gateway (21:1/5)

To: [email protected] (Dmitri Pal)
Copy: [email protected] ([email protected])

Robert Sturrock <[email protected]> writes:

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?

For context, the full error is:

kvno: KDC returned error string: HANDLE_AUTHDATA while getting credentials for host/[email protected]EALM

Anyway, first step is to check the KDC logs (since that's who generated
the error) - there's possibly more information there.

Thanks,
--Robbie

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Copy: [email protected] ([email protected])

On Mon, Jun 15, 2020 at 9:49 PM Robert Sturrock <[email protected]> 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 <[email protected]> wrote:

UoM notice: External email. Be cautious of links, attachments, or

impersonation attempts.

On Mon, Jun 15, 2020 at 2:39 AM Robert Sturrock <[email protected]>

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 [email protected]EALM: XXXXXXXXX

$ klist
Ticket cache: KEYRING:persistent:10846:10846
Default principal: [email protected]EALM

Valid starting Expires Service principal
11/06/20 13:34:19 11/06/20 23:34:19

krbtgt/[email protected]EALM

renew until 12/06/20 13:34:18

# Use AD TGT to get an IPA TGT:
$ kvno krbtgt/[email protected]EALM
krbtgt/[email protected]EALM: kvno = 0

$ klist
Ticket cache: KEYRING:persistent:10846:10846
Default principal: [email protected]EALM

Valid starting Expires Service principal
11/06/20 13:34:24 11/06/20 23:34:19

krbtgt/[email protected]EALM

renew until 12/06/20 13:34:18
11/06/20 13:34:19 11/06/20 23:34:19

krbtgt/[email protected]EALM

renew until 12/06/20 13:34:18

# Try to fetch an IPA service ticket:
$ kvno host/[email protected]EALM
kvno: KDC returned error string: HANDLE_AUTHDATA while getting

credentials for host/[email protected]EALM

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 [email protected] https://mailman.mit.edu/mailman/listinfo/kerberos

--
Thank you,
Dmitri Pal
Director, Software Engineering
Red Hat Enterprise Linux Platform Security and Identity Management [email protected]

--

Thank you,
Dmitri Pal

Director, Software Engineering
Red Hat Enterprise Linux Platform Security and Identity Management [email protected]
<https://red.ht/sig>

--- SoupGate-Win32 v1.05
* Origin: fsxNet Usenet Gateway (21:1/5)