Kerberos Ticket not renewed anymore after being forwarded.

[vm@c4k3.space]

So far my attempt to ask it to the community :-)
But I think I finally managed to find the explanation.
So in case someone else ever has the same problem, searches why and 
stumbles onto this page...

The kadmin-protocol that differs between the heimdal-implementation used 
in Mac OS and the MIT-implementation on linux seems to be the culprit.

http://kerberos.996246.n3.nabble.com/Lion-problems-tc13877.html

|
| Mar 12, 2012; 9:52pm  Arthur Prokosch-2 Arthur Prokosch-2
| ...
| We've wandered into Heimdal territory here and should probably switch
| to [hidden email] or discussions.apple.com.  In the meantime:
| if anyone else has seen Mac OS 10.7 Heimdal tickets lose their
| Forwardable and Proxiable flags in the process of initiating GSSAPI
| ssh connections or has an explanation, I'd be quite interested to hear
| off-list.
|
| best,
| -arthur prokosch
| system administrator
| [1]MIT Computer Science and Artificial Intelligence Lab.
| ...


In the meantime I also tested it on MacOS Sierra. Problem is still 
there.

I don't know if there is any solution though.

P.S. Anybody who confirms my hypothesis?



vm at c4k3.space schreef op 2016-10-26 14:21:
> Hi,
> 
> I hope I'm at the right place here for my issue.
> 
> This is the case:
> 
> 
> On my macbook (Mac OS X 10.11), I have a renewable Kerberos-ticket:
> 
> ---
> macbook013:~ vm$ klist -v
>   Credentials cache: API:EF9959E6-85DF-446F-9B21-3CEEC606FA2D
>           Principal: vm at REALM.COM
>       Cache version: 0
> 
>   Server: krbtgt/REALM.COM at REALM.COM
>   Client: vm at REALM.COM
>   Ticket etype: aes256-cts-hmac-sha1-96, kvno 1
>   Ticket length: 342
>   Auth time:  Oct 26 13:55:09 2016
>   End time:   Nov 25 12:55:05 2016
>   Renew till: Jan 26 12:55:05 2017
>   Ticket flags: enc-pa-rep, pre-authent, initial, renewable, proxiable,
> forwardable
>   Addresses: addressless
> ---
> 
> If I do a ssh (GSSAPIAuthentication yes,GSSAPIDelegateCredentials yes)
> to a linux-server, the ticket there is not renewable anymore:
> 
> ---
>   macbook013:~ vm$ ssh linuxserver2
>   linuxserver2 ~ # klist -f
>   Ticket cache: FILE:/tmp/krb5cc_1379_BZVstF6000
>   Default principal: vm at REALM.COM
> 
>   Valid starting     Expires            Service principal
>   10/26/16 14:00:30  11/25/16 12:55:05  krbtgt/REALM.COM at REALM.COM
>          Flags: FfPAT
>   linuxserver2 ~ # krenew
>   krenew: error renewing credentials: KDC can't fulfill requested 
> option
>   linuxserver2 ~ # kinit -R
>   kinit: KDC can't fulfill requested option while renewing credentials
> ---
> 
> If I do a kinit on linuxserver1 and get a renewable ticket there and 
> ssh
> to linuxserver2, the forwarded ticket stays renewable.
> 
> I guess it has something to do with the ssh-client on Mac OS X? (but
> copying the ssh_config from linuxserver1 to the macbook does not solve
> it. Copying the krb5.conf doesn't solve it either)
> Or should I search the cause in another direction?
> Maybe I'm missing something obvious.
> 
> 
> Thank you for thinking with me!
> 
> VM
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