Thanks a lot Alexander.

From: Alexander Bokovoy <abokovoy@redhat.com>
Sent: 20 May 2022 13:39
To: FreeIPA users list <freeipa-users@lists.fedorahosted.org>
Cc: Angus Clarke <angus@charworth.com>
Subject: Re: [Freeipa-users] hostgroup automember rules
 
Hi Angus,

On pe, 20 touko 2022, Angus Clarke via FreeIPA-users wrote:
>Hello
>
>FreeIPA 4.6.8
>
>We are very happy with hostgroup automember rules based on servername
>attribute however one of our internal customers uses a generic
>servername template for all of their servers regardless of its
>function.
>
>So I'm wondering what other attributes I might use for hostgroup
>automember - perhaps some of the attributes can be configured by the
>ipa-client-install (the host's "description" field perhaps) although I
>don't see such mention in the man page ... Presumably they could use a
>different enrollment user ("enrolledby") for each of their hostgroup
>functions (not ideal.)
>
>There are various attribute fields in the WebUI but I don't find much
>documentation for them. What is the "|" field - perhaps I can exploit
>this somehow?

Few years ago a customer of mine asked a similar question. Here is what
I answered:

----------------------------------------------------------------------
You can use nsHardwarePlatform attribute (part of nsHost objectclass).
It is exposed as '--platform' in IPA CLI for 'ipa host-*' commands.

Originally it was supposed to be filled by the IPA client join process
to 'uname -m' value. ipa-join tools still sends it to the server but the
value is ignored completely by the join process. As the result,
nsHardwarePlatform attribute is never set on the host object.

I don't see any code in IPA itself that would rely on the content of
nsHardwarePlatform attribute. We have web UI tests upstream that modify
the field to test that you can modify it but that's all.

Alternatively, one can use userClass attribute (--class in IPA CLI for
host-* commands). This one is also not utilized and is left specifically
for the customers to define its semantics.

Another alternative is nsHostLocation attribute (--location in IPA CLI for host-*
commands). Again, the semantics is totally left for customers to define.

----------------------------------------------------------------------

There are two ways of setting these fields:

  - prior to enrollment, by pre-creating a host and setting the
    attributes at that time.

  - after the enrollment, right from the host using host keytab

The former can be done by a designated user/service account and can be
tuned with custom permissions to allow such modification. The latter
relies on the fact that the host principal has some write rights
already:

# kinit -k

# ipa host-show `hostname` --rights --all
   dn: fqdn=dc.ipa.test,cn=computers,cn=accounts,dc=ipa,dc=test
   Host name: dc.ipa.test
   Principal name: host/dc.ipa.test@IPA.TEST
   Principal alias: host/dc.ipa.test@IPA.TEST
   SSH public key: [skip]
   SSH public key fingerprint: [skip]
   Requires pre-authentication: True
   Trusted for delegation: False
   Trusted to authenticate as user: False
   Password: False
   Member of host-groups: ipaservers
   Keytab: True
   Managed by: dc.ipa.test
   Managing: dc.ipa.test
   attributelevelrights: {'aci': '', 'cn': 'rscwo', 'description': 'rscwo', 'enrolledby': 'rsc', 'fqdn': 'rsc', 'ipaassignedidview': 'rsc', 'ipaclientversion': 'rsc', 'ipakrbauthzdata': 'rsc', 'ipasshpubkey': 'rscwo', 'ipauniqueid': 'rsc', 'krballowedtodelegateto': '', 'krbauthindmaxrenewableage': '', 'krbauthindmaxticketlife': '', 'krbcanonicalname': 'rsc', 'krbextradata': '', 'krblastadminunlock': '', 'krblastfailedauth': '', 'krblastpwdchange': 'rscwo', 'krblastsuccessfulauth': '', 'krbloginfailedcount': '', 'krbmaxrenewableage': '', 'krbmaxticketlife': '', 'krbobjectreferences': '', 'krbpasswordexpiration': 'rsc', 'krbprincipalaliases': 'rsc', 'krbprincipalauthind': 'rsc', 'krbprincipalexpiration': 'rsc', 'krbprincipalkey': 'swo', 'krbprincipalname': 'rsc', 'krbprincipaltype': '', 'krbpwdhistory': '', 'krbpwdpolicyreference': '', 'krbticketflags': '', 'krbticketpolicyreference': '', 'krbupenabled': '', 'l': 'rscwo', 'managedby': 'rsc', 'memberof': 'rsc', 'nsaccountlock': '', 'nshardwareplatform': 'rscwo', 'nshostlocation': 'rscwo', 'nsosversion': 'rscwo', 'objectclass': 'rsc', 'serverhostname': 'rsc', 'usercertificate': 'rscwo', 'userclass': 'rsc', 'userpassword': 'swo'}
   cn: dc.ipa.test
   ipauniqueid: b179f1ea-c4b8-11ec-9e86-52540083ff9d
   krblastpwdchange: 20220425165647Z
   objectclass: top, ipaobject, nshost, ipahost, ipaservice, pkiuser, krbprincipalaux, krbprincipal, krbticketpolicyaux, ipasshhost, ipaSshGroupOfPubKeys
   serverhostname: dc

So, the host/dc.ipa.test@IPA.TEST principal can write to:

   - nsHardwarePlatform
   - nsHostLocation
   - nsOSVersion
   - l (locality)
   - description

but it cannot write to 'userClass' attribute.

A handy mapping between attributes and command parameters is
'show-mappings' command:

# ipa show-mappings host-mod
Parameter              : LDAP attribute
=========              : ==============
desc                   : description?
locality               : l?
location               : nshostlocation?
platform               : nshardwareplatform?
os                     : nsosversion?
password               : userpassword?
random                 : random?
certificate            : usercertificate*
krbprincipalname       : krbprincipalname*
macaddress             : macaddress*
sshpubkey              : ipasshpubkey*
class                  : userclass*
auth-ind               : krbprincipalauthind*
requires-pre-auth      : ipakrbrequirespreauth?
ok-as-delegate         : ipakrbokasdelegate?
ok-to-auth-as-delegate : ipakrboktoauthasdelegate?
rights                 : rights
updatedns              : updatedns?

If you want to change parameters from the host itself, it would be
possible with

# kinit -k
# ipa host-mod `hostname` --locality=foo --location=bar --platform=some-platform --desc=some-host

--
/ Alexander Bokovoy
Sr. Principal Software Engineer
Security / Identity Management Engineering
Red Hat Limited, Finland