mit-krb5 and heimdal binaries

[Alexander Bokovoy]

On su, 19 maalis 2023, Rowland Penny via samba-technical wrote:
> 
> 
> On 19/03/2023 08:07, Alexander Bokovoy wrote:
> > On su, 19 maalis 2023, Rowland Penny via samba-technical wrote:
> > > 
> > > 
> > > On 19/03/2023 07:29, Alexander Bokovoy via samba-technical wrote:
> > > > Hi,
> > > > 
> > > > On su, 19 maalis 2023, Michael Tokarev via samba-technical wrote:
> > > > > Hi!
> > > > > 
> > > > > I already asked a similar question before, but it keeps popping up in different
> > > > > contexts and forms, and the more I use samba myself, the more often it comes to
> > > > > me too, especially in context of using various security tokens for auth.  And the
> > > > > more I think about all this, the more sane it looks to me.
> > > > > 
> > > > > The thing is: mit-krb5 has much better user-level support than heimdal. But samba
> > > > > does not fully support mit-krb5 as an active directory domain controller.  The
> > > > > AD-DC thing is server-side.
> > > > > 
> > > > > I can think of providing two builds of samba for a distribution (eg debian/ubuntu), -
> > > > > one implementing whole ad-dc, as a complete thing, using their own set of libs,
> > > > > linked with heimdal. And a usual set of more client-side packages, with their own
> > > > > libraries, built against mit-krb5.  Or maybe some other combination also has its
> > > > > right to be, - for example, smbclient built with mit-krb5, the rest is heimdal.
> > > > > 
> > > > > An essential part of this is that the two sets (built against mit-krb5 and heimdal)
> > > > > do not share any internal libraries, each has its own libraries. This way, there's
> > > > > no "mix" of differently built samba, each build uses only its own libs, so there's
> > > > > no clash here.  They share the same smb.conf though.
> > > > > 
> > > > > So far, I've seen requests to build two versions of the server (again, with mit-krb5
> > > > > and with heimdal), - and I faced the same issues too.  This is because a regular AD
> > > > > member server is also good to have mit-krb5 support to integrate nicely into the auth
> > > > > infrastructure. While for ad-dc, it is less often used as "end-user" server.
> > > > > 
> > > > > So I can think of a separate samba-ad-dc binary package providing whole samba suite
> > > > > built against heimdal (maybe without smbclient and some other minor things), and
> > > > > samba "file server" binary package providing regular server not suitable to use as
> > > > > an ad-dc, but conflicting with samba-ad-dc, so it is not possible to install one
> > > > > together with another.
> > > > > 
> > > > > This approach also has another good side effect, to discourage usage of samba-ad-dc
> > > > > as a regular file server.
> > > > > 
> > > > > Or maybe the whole thing is moot now, and we just can provide regular samba built
> > > > > against mit-krb5 to work as a good AD-DC?  That would be the best solution IMHO.
> > > > 
> > > > I would be against a blended build against both MIT Kerberos and Heimdal
> > > > Kerberos in a distribution. It is not going to bring you anything good,
> > > > support wise.
> > > > 
> > > > Andreas and I have submitted a talk to SambaXP about MIT
> > > > Kerberos/Heimdal Kerberos-based Samba AD DC configurations, where they
> > > > stand against each other and what are perspectives. In short, both have
> > > > unique features that do not exist in the other variant and both are
> > > > close to being production-ready. We want to change the status for MIT
> > > > Kerberos-based build from experimental to production. Effectively,
> > > > actual decision for a version shipped in a particular distribution would
> > > > need to be made by that distribution, of course.
> > > 
> > > I do not think this is a good idea, Samba should use one or the other, not
> > > both. If you do use both, to a certain extent you will nearly double the
> > > support required.
> > 
> > I did say exactly that: I am against blended build. Not sure what made
> > you think otherwise.
> > 
> > > 
> > > > 
> > > > Distributions need to take into account security releases, as Rowland
> > > > has pointed out as well. However, from my Fedora and RHEL experience,
> > > > this is not a problem with MIT Kerberos -- certainly not more than with
> > > > Heimdal. It is pretty much a coordination question and I believe we have
> > > > very good coordination on that front with MIT Kerberos and distribution
> > > > maintainers.
> > > 
> > > That is strange, from what Andrew wrote, he appears to think the opposite.
> > 
> > I am one of developers and one of maintainers for both Samba and MIT
> > Kerberos in Fedora and RHEL (as well as few other relevant projects). I
> > personally see no issues with MIT Kerberos upstream collaboration.
> > Things get discussed and fixed when needed, contributions get accepted.
> > Our willingness to move Samba AD/MIT support from experimental forward
> > to supported is based on that factor as well.
> > 
> > > > 
> > > > If I was in Samba AD support for production deployments, I'd probably
> > > > go with deploying DCs in a containerized image way to isolate completely
> > > > from the rest of the OS. There are few images already that provide this
> > > > setup: [1] was presented at SambaXP by Michael Adam and other folks now
> > > > from IBM Storage, [2] is older and also active one.
> > > > 
> > > > [1] https://github.com/samba-in-kubernetes/samba-container
> > > > [2] https://github.com/instantlinux/docker-tools/tree/main/images/samba-dc
> > > > 
> > > 
> > > I personally have no axe to grind over the matter, I do not care which kdc
> > > is used, just as long as it is only one, if only from the support point of
> > > view.
> > > I also only say that using MIT is experimental because other wiser (at least
> > > I hope they are wiser than me) people say it is, if this changes then so be
> > > it.
> > > 
> > > I still do not think it is a good idea for a distro to provide two versions
> > > of Samba, one using Heimdal and the other using MIT.
> > 
> > Yep. However, tools we have in most distributions allow to provide more
> > flexibility. It all needs maintainers, though. Without maintainers there
> > is just an illusion that someone could depend on a package that is in
> > reality not supported well -- whether it is built with a single scenario
> > in mind or set up to handle multiple approaches.
> > 
> 
> Alexander, as I said, I do not have an axe to grind in this, if Samba
> decides to move to MIT, then so be it. You however, do have  an axe to
> grind, you work for red-hat, who are on record as saying that there will
> never be an AD DC on RHEL. Are you now saying that, if Samba moves to MIT,
> there will be ?

I don't say that. What I said is that I am responsible for both Fedora
and RHEL. Fedora does provide Samba AD DC already for several years,
using MIT Kerberos backend. That's what I stand behind and will continue
to support.


-- 
/ Alexander Bokovoy