[Freeipa-users] interesting Kerberos issue

[Nathaniel McCallum]

On Mon, 2015-05-18 at 17:18 +0300, Alexander Bokovoy wrote:
> On Mon, 18 May 2015, Nathaniel McCallum wrote:
> > On Mon, 2015-05-18 at 17:03 +0300, Alexander Bokovoy wrote:
> > > On Mon, 18 May 2015, Janelle wrote:
> > > > On 5/10/15 11:57 PM, Alexander Bokovoy wrote:
> > > > > On Sun, 10 May 2015, Janelle wrote:
> > > > > > On 5/5/15 6:47 AM, Dmitri Pal wrote:
> > > > > > > On 05/04/2015 09:38 PM, Janelle wrote:
> > > > > > > > On 5/4/15 6:06 PM, Nathaniel McCallum wrote:
> > > > > > > > > On Mon, 2015-05-04 at 08:49 -0700, Janelle wrote:
> > > > > > > > > > Happy Star Wars Day!
> > > > > > > > > > May the Fourth be with you!
> > > > > > > > > > 
> > > > > > > > > > So I have a strange Kerberos problem trying to 
> > > > > > > > > > figure
> > > > > > > > > > out. On a
> > > > > > > > > > CLIENT,  (CentOS 7.1) if I login to account "usera"
> > > > > > > > > > they get a
> > > > > > > > > > ticket as
> > > > > > > > > > expected.  However, if I login to a 6.6 client, it
> > > > > > > > > > doesn't seem to
> > > > > > > > > > work.
> > > > > > > > > > Both were enrolled the same, obviously one is 
> > > > > > > > > > newer.
> > > > > > > > > > 
> > > > > > > > > > Now, it gets stranger. The "servers" are CentOS 7.1
> > > > > > > > > > also. If I login
> > > > > > > > > > as
> > > > > > > > > > root, bypassing kerberos, and then do "kinit admin" 
> > > > > > > > > > it
> > > > > > > > > > works just
> > > > > > > > > > fine.
> > > > > > > > > > But if I do "kinit usera" I get:
> > > > > > > > > > 
> > > > > > > > > > kinit: Generic preauthentication failure while 
> > > > > > > > > > getting
> > > > > > > > > > initial
> > > > > > > > > > credentials
> > > > > > > > > > 
> > > > > > > > > > Which makes no sense. The account works with a 7.1
> > > > > > > > > > client but not a
> > > > > > > > > > 6.x
> > > > > > > > > > client?? And yet "admin" works, no matter what. 
> > > > > > > > > > What am
> > > > > > > > > > I missing
> > > > > > > > > > here?
> > > > > > > > > If I had to guess, usera is enabled for OTP-only 
> > > > > > > > > login.
> > > > > > > > > Is that
> > > > > > > > > correct?
> > > > > > > > > 
> > > > > > > > > If so, clients require RHEL 7.1 for OTP support. 
> > > > > > > > > Also,
> > > > > > > > > the error you
> > > > > > > > > are getting is the result of not enabling FAST 
> > > > > > > > > support
> > > > > > > > > for OTP
> > > > > > > > > authentication (see the -T option).
> > > > > > > > > 
> > > > > > > > > Nathaniel
> > > > > > > > Ok, this did give me an idea (Thanks Nathaniel)  -- the
> > > > > > > > account was set for BOTH "password" and OTP.
> > > > > > > > Apparently setting both does nothing. Yes a user can 
> > > > > > > > login
> > > > > > > > with their password-only, but trying to use kinit does 
> > > > > > > > not
> > > > > > > > work.
> > > > > > > > 
> > > > > > > > I am not sure I understand where the FAST support or 
> > > > > > > > the -T
> > > > > > > > 
> > > > > > > > option is to be applied. On kinit? That does not seem
> > > > > > > > correct.
> > > > > > > > Perhaps I am misunderstanding this option?
> > > > > > > > 
> > > > > > > > ~J
> > > > > > > > 
> > > > > > > If the user is enabled for OTP his credential are sent
> > > > > > > differently than in the case when it is not enabled.
> > > > > > > Effectively
> > > > > > > instead of using encrypted timestamp the password and OTP 
> > > > > > > are
> > > > > > > 
> > > > > > > sent to the server as data. But they can't be sent in 
> > > > > > > clear.
> > > > > > > You
> > > > > > > need to encrypt the data. To encrypt it you need another 
> > > > > > > key
> > > > > > > -
> > > > > > > the host key. The encryption of the data in this context 
> > > > > > > is
> > > > > > > called tunneling . FAST is the Kerberos protocol feature 
> > > > > > > to
> > > > > > > provide tunneling of the data sent over the wire. To use 
> > > > > > > FAST
> > > > > > > 
> > > > > > > one needs to use -T on the kinit command line.
> > > > > > > Does this help?
> > > > > > > 
> > > > > > It helps -- thank you.
> > > > > > 
> > > > > > Now allow me to add a little more fun, and there may not be 
> > > > > > a
> > > > > > solution.
> > > > > > > From OS X (Yosemite) I am able to "kinit --kdc
> > > > > > > -hostname=IPA
> > > > > > > -server
> > > > > > principal" and it works, gives me a ticket, and if I 
> > > > > > attempt to
> > > > > > 
> > > > > > login to the web interface, since I already have my ticket 
> > > > > > -
> > > > > > boom,
> > > > > > works fine.
> > > > > > 
> > > > > > Now, I enable 2FA and setup a token and change my account 
> > > > > > to
> > > > > > OTP
> > > > > > (with TOTP).  But as previously discussed, can't seem to
> > > > > > specify a
> > > > > > -T option from OS X.
> > > > > > 
> > > > > > I know this sounds tricky -- Any ideas?
> > > > > Use
> > > > > kinit --fast-armor-cache /path/to/ccache to specify already
> > > > > existing ccache to armor the FAST processing.
> > > > > 
> > > > > This is Heimdal-specific, and you should have Heimdal 1.6rc2 
> > > > > at
> > > > > least.
> > > > > You can check version number by running 'kinit --version'.
> > > > Aha, so thee default on OS X Yosemite is
> > > > 
> > > > $ kinit --version
> > > > kinit (Heimdal 1.5.1apple1)
> > > > 
> > > > so this won't work?
> > > Yes, you have to have the feature in your Kerberos library.
> > 
> > Browsing the Heimdal source code, I don't even see any support for 
> > OTP
> > at all. :(
> The support is since 1.6rc2, it uses the Richards' draft
> (draft-richards-otp-kerberos-01.txt) as a base and handles preauth 
> but I
> don't think anything but login and ftpd supports passing the OTP 
> token.

Where is the code? I don't see any...

Nathaniel