On 03/23/2014 06:59 PM, Nordgren, Bryce L -FS wrote:

I’m not, in general, in favor of solutions which promiscuously sling Kerberos passwords around the net. JpGina + Kerberos authenticating directly off of IPA would be the way to go, I think.

Presumably Dimitri’s statement about the user being “foreign” and having limited access to windows services would apply equally well to a user with a SID from a foreign domain in a large Kerberos federation. This, and the uncertainty concerning what type of directory service the foreign KDC is paired with, is probably responsible for keeping Kerberos-based federations small.


If you have a SID you can tell Windows what t odo with it and how to resolve it to name. If you do not have one you can't do anything if you accessing elements of the Windows infra.

That being said, the collaboration use case (not to mention “home networks”) is what makes “foreign” logins interesting. There’s hardly anything in common between two collaboration projects, so it’s hard to define far-reaching policies (i.e., you’re not missing out on much). Most all authorization decisions are delegated out to some project member responsible for the server/asset. Constructing authorization sets having members defined by text based principals makes a certain amount of sense. Hence the LDAP “member” attribute in RFC4519.


Collaboration can be in different ways. It all depends on the use case. It can be OpenID, SAML, Kerberos, etc. There are different technologies and they suit better different use cases.

What would really be cool is the “inverse” of gluu or openam. Kerberos preauthentication data which allows the KDC to authenticate off of an OpenID Connect, SAML, or LDAP authentication source, caching the provided password and provisioning a Kerberos principal. Future AS exchanges would start out as “normal” Kerberos. Sort of like migration mode does now. If the KDC could then signal IPA that a new principal was provisioned, IPA could allocate and harmonize an SID and a UID for the principal in the domain.


It is already to some extend possible. It is called "constrained delegation". The problem is that the gateway that would do such protocol conversion would be able to impersonate any user in the Kerberos realm. This is not the best but since it is being asked we are looking into it. There is a project called Ipsilon https://git.fedorahosted.org/git/ipsilon that is building the way of federating different applications via SAML but in future it might be extended to the workflows you are talking about here though I am not sure I met these use cases in practice. Can you please share under what circumstances such "inversion" would actually be needed?

Poof. Console logins for Windows (pGina) and Linux (sssd) using IPA backed by your google account. That just eliminated 98% of the external accounts you would have had to create and manage.


Your Google account does not use Kerberos that means that your password goes over the wire. The whole point of Kerberos that password does not go the wire. That being said modern Kerberos server and client support OTP preauthentication method. This method can be used (abused) to proxy to any RADIUS server including the one provided by Google. So if you use Google 2FA then it becomes more interesting. You can extually try it now with the latest upstream bits. It is not 100% complete but good enough to give it a try. We are also working with MIT to make sure that one can use IPA with Kerberos password + HOTP/TOTP token. Then instead of sending the authentication to the external entity (RADIUS server) the token code would be processed by IPA, but to make is more secure and not send the password over the wire together with OTP, KDC and client need to support authentication sets. It is a feature that we will be looking to have in a 1.14 Kerberos release.

Food for thought.

Bryce

*From:*freeipa-users-boun...@redhat.com [mailto:freeipa-users-boun...@redhat.com] *On Behalf Of *Dmitri Pal
*Sent:* Saturday, March 22, 2014 5:55 PM
*To:* Will Sheldon
*Cc:* freeipa-users@redhat.com
*Subject:* Re: [Freeipa-users] About Windows client

On 03/22/2014 05:47 PM, Will Sheldon wrote:

I’d be curious to see how well a solution that combines pGina using RADIUS against some middleware like the Gluu server (www.gluu.org <http://www.gluu.org>) backed by IPA would work.


This is not an interesting scenario. This would would probably work right now but the machine would still not know who the user is because it will not know user SID so he would be foreign and no Windows policies would apply to him. I suspect such user would have no or very limited read only access to Windows resources because all Windows ACLs are based on knowing the user SIDs and SIDs of the groups the user is a member of. The value of native IdM integration would be to get user SID and SIDs of the groups from IdM and then get the right kerberos ticket(s) for Windows resources using cross realm kerberos trusts and put these tickets into the right place so that windows system can use them automatically when user navigates to the corresponding resource. Something like this.


It strikes me that getting domain federation between IPA and Gluu would tick a lot of boxes as it seems to offer a host of authentication and accounting interfaces including oAuth, SAML, OpenID and of course RADIUS.


Kind regards,

Will Sheldon
+1.778-689-1244

On Saturday, March 22, 2014 at 2:17 PM, Dmitri Pal wrote:

    On 03/22/2014 01:18 PM, Arthur wrote:

        Dmitri Pal wrote:

            On 03/20/2014 11:15 PM, Arthur Faizullin wrote:

                HI!

                I've got some thoughts on 4-th point: there is a
                http://pgina.org/

                pgina

                project, may be them are able to do such thing.

            Yes pgina is one of the options.

            Someone would have to take it and integrate with MIT
            Kerberos for

            Windows if it is not already doing so.

            But I suspect that it would be more a project in itself
            that would

            leverage code from MIT and may be pgina to integrate
            different parts.

            The biggest part figuring out the domain affiliation. I
            mean the use

            cases like this:

            a) The system is domainless but user authentictaes with
            user name and

            password against IPA

            b) The system is domainless but user authentictaes with
            user name and

            OTP against IPA

            c) The system is in an AD domain trusted by IdM domain but
            user

            authenticates with user name and password against IPA
            because he is

            in IdM domain.

            d) The system is in an AD domain trusted by IdM domain but
            user

            authenticates with user name and password against IPA
            because he is

            in IdM domain.

            More to research. We can help with guidance if someone
            wants to run

            with it.

            Thanks

            Dmitri

                20.02.2014 04:23, Dmitri Pal пишет:

                    Hello,

                    I want to summarize our position regarding joining
                    Windows systems

                    into IPA.

                    1) If you already have AD we recommend using this
                    system with AD and

                    using trusts between AD and IPA.

                    2) If you do not have AD then use Samba 4 instead
                    of it. It would be

                    great when Samba 4 grows capability to establish
                    trusts. Right now it

                    can't but there is an effort going on. If you are
                    interested - please

                    contribute.

                    3) If neither of the two options work for you you
                    can configure

                    Windows system to work directly with IPA as
                    described on the wiki. It

                    is an option of last resort because IPA does not
                    provide the services

                    windows client expects. If this is good enough for
                    you, fine by us.

                    4) Build a native Windows client (cred provider)
                    for IPA using latest

                    Kerberos. IMO this would be really useful if
                    someone does that because

                    we will not build this ourselves. With the native
                    OTP support in IPA

                    it becomes a real business opportunity to provide
                    a native 2FA inside

                    enterprise across multiple platforms. But please
                    do it open source way

                    otherwise we would not recommend you ;-)

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        My friend agreed to try. He is C# programmer. But the problem
        that has

        low knowledge about kerberos, GSSAPI, and I could not told him
        what is

        wrong with current pgina's ldap plugin.

        He does not want to subscribe to freeipa mail-lists, so may be
        I shall

        give him your (Dmitri) e-mail?

        He speaks russian :)

    List is really the way to develop open source software
    collaboratively.

    This is what we are doing here.

    We can agree that the communication about the topic will be
    prefixed in

    such a way that he can create a filter so that he would get only
    mails

    that match the filter.

    Would that work?

    I am not sure that I would be able to provide all the support. We
    are a

    community here and we have different roles and angles. Working
    with just

    one person would not fly, sorry.

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--
    Thank you,

    Dmitri Pal

    Sr. Engineering Manager for IdM portfolio

    Red Hat Inc.

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--
Thank you,
Dmitri Pal
Sr. Engineering Manager for IdM portfolio
Red Hat Inc.
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Thank you,
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Red Hat Inc.


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