Re: [netconf] built-in trust anchors

[Juergen Schoenwaelder <[e-mail]>]

After sleeping over it, I think a device should ship with the keys
listed in whatever is the equivalent of the factory default, i.e.,
they are initially in <running>. Deleting them should be possible with
the effect that no config can refer to these keys anymore (assuming
strong references). Putting the keys back into running makes them
available for config again.

I would be in favour to just have the names in runnning, not the
key/cert details. This avoids issues with entries that do not match,
and this then resembles hidden keys, for which details are also not
known in <running>. In fact, <hidden> keys likely have the same
property that they exist in the system (or a TPM), i.e., they are not
config that can be arbitrary changed. I would assume that the same
rules apply, if you delete a hidden key from <running>, it can't be
referenced and used anymore. Perhaps the discussion in the I-D should
be expanded to cover hidden keys as well.

I also expect that these special keys may be part of the firmware,
i.e., they may change with firmware updates. This can lead to stale
special keys that do not exist anymore in the firmware and new keys
that exist in the firmware but must be (manually) added to <running>
in order to use them.

/js

On Tue, Jan 12, 2021 at 10:59:28PM +0000, Sterne, Jason (Nokia - CA/Ottawa) wrote:
> Yes - adding require-instance false would eliminate the issue about built-in anchors in <running>. But there are useful advantages to keeping require-instance true. I don't have a strong feeling though one way or the other.
> 
> But assuming we keep require-instance true then the question still remains of how built-in items get into <running> (and are they deletable, and do we only need keys in running, etc).
> 
> Jason
> 
> > -----Original Message-----
> > From: Juergen Schoenwaelder <[e-mail]>
> > Sent: Tuesday, January 12, 2021 3:00 PM
> > To: Sterne, Jason (Nokia - CA/Ottawa) <[e-mail]>
> > Cc: Netconf <[e-mail]>
> > Subject: Re: [netconf] built-in trust anchors
> > 
> > Jason,
> > 
> > since the leafref typedefs are weak references that do not require
> > that the certs/keys exist (there is no 'require-instance true'), it
> > may be OK to not have the certs/keys in <running> in terms of validity
> > of the <running> datastore.
> > 
> > Oops, I had to reread RFC 7950 (section 9.9.3): if require-instance is
> > not present, it defaults to true, so my review comment about weak
> > references is incorrect, these are actually strong references and
> > hence there is the need to copy what is referenced. Setting
> > require-instance to false may resolve this (but we loose the ability
> > to catch references to certs/keys that do not exist).
> > 
> > /js
> > 
> > On Tue, Jan 12, 2021 at 07:02:04PM +0000, Sterne, Jason (Nokia - CA/Ottawa)
> > wrote:
> > > Hi all,
> > >
> > > I noticed Jurgen's comment about built-in trust anchors in his YANG doctor
> > review of trust-anchors-13. I wanted to pull that out into a dedicated
> > thread/discussion here.
> > >
> > > Jurgen:
> > >
> > >
> > > - Section 3 talks about populating <running> with built-in trust
> > >
> > >   anchors.
> > >
> > >
> > >
> > >    In order for the built-in trust anchors to be referenced by
> > >
> > >    configuration, the referenced certificates MUST first be copied into
> > >
> > >    <running>.  The certificates SHOULD be copied into <running> using
> > >
> > >    the same "key" values, so that the server can bind them to the built-
> > >
> > >    in entries.
> > >
> > >
> > >
> > >   Is the idea that this copy operation is an explicit management
> > >
> > >   operation or can implementations populate <running> with this
> > >
> > >   data automatically?
> > >
> > > I suppose a server *could* populate this in running as part of a built-in
> > startup datastore in the absence of a startup datastore (i.e. as contents of a
> > RFC8808 factory default). But I assume it is desirable to be able to delete the
> > running copy of a built-in item. So the system would have to avoid populating
> > these unless it is loading the factory default.
> > >
> > > But even if the system can populate these, we'd also want the client/user
> > to be able to explicitly populate them as well (i.e. in case they delete one
> > from running, and want to add it back in to reference it).
> > >
> > > In either case (system population of running, or client population of
> > running), do we really need to put the contents of the bag or the cert into
> > running?  Or is populating the list key enough since the operational copy
> > shows what contents are in use for that list entry?
> > >
> > > Jason
> > 
> > > _______________________________________________
> > > netconf mailing list
> > > [e-mail]
> > > https://www.ietf.org/mailman/listinfo/netconf
> > 
> > 
> > --
> > Juergen Schoenwaelder           Jacobs University Bremen gGmbH
> > Phone: [phone]         Campus Ring 1 | 28759 Bremen | Germany
> > Fax:   [phone]         <https://www.jacobs-university.de/>

-- 
Juergen Schoenwaelder           Jacobs University Bremen gGmbH
Phone: [phone]         Campus Ring 1 | 28759 Bremen | Germany
Fax:   [phone]         <https://www.jacobs-university.de/>