Re: [Geopriv] draft-ietf-geopriv-rfc3825bis

From: Tschofenig, Hannes (NSN - FI/Espoo) ^lt;hannes.tschofenig@nsn.com>
Date: Tue Aug 17 2010 - 03:46:11 EDT

> At 08:09 AM 8/10/2010, Tschofenig, Hannes (NSN - FI/Espoo) wrote:
> >Think about a regular hotel network.
>
> many/most wired hotel networks are DSL-like based, so this doesn't
> apply as directly as it may seem.

Whether the hotel network provider uses DSL or Cable does not matter for
this purpose.

>
> What you are suggesting (that the server MUST NOT hand out location
> in shared mediums) is requiring a DHCP server to have physical
> topological awareness before implementing option 123. The same DHCP
> server can be unaware of ever network topology between it and the
> client - therefore I believe you are placing an excessive burden or
> limitation on DHCP as an LCI delivery means.

The GEOPRIV working group is about describing what privacy properties
are being provided for the solutions we develop. You have always been
quite keen on documenting everything in detail -- particularly when
other people proposed something.

Describing what we assume are reasonable operational considerations that
are applicable is a good thing, I believe.
We cannot have all these chats about how important privacy is for us but
then when it actually has an operational impact then we back-off.

In this specific case, I am not sure I understand what you mean with
additional requirements. A DHCP server better has an idea about the
network topology since otherwise how does it hand out the IP addresses
and other configuration parameters.

>
> I'm concerned about the SMB or residential gateway impact of adding
> this context - which can easily lead to some vendor(s) reading what
> you are proposing and consider DHCP not appropriate for homes or
> small businesses inadvertently, where it otherwise would be logical
> to use. Many gateways of this sort have DHCP as a client to the WAN,
> and as a server to the LAN.
>
> We need to be careful with how we word any changes.

There are two parts here:

1) The first part is to describe what the privacy risks are with the
technology
2) The second part is to make some recommendations for anticipated
envionments.

With SMBs and the usage of this document you are touch on item #2. Your
recommendation would be that the privacy risks are not so dramatic in
such an environment and I believe it is OK to say that.

You still want to talk about item #1 in the document.

Ciao
Hannes

>
> James
>
>
> > > -----Original Message-----
> > > From: ext Marc Linsner [mailto:mlinsner@cisco.com]
> > > Sent: Tuesday, August 10, 2010 3:59 PM
> > > To: Tschofenig, Hannes (NSN - FI/Espoo); geopriv@ietf.org
> > > Subject: Re: [Geopriv] draft-ietf-geopriv-rfc3825bis
> > >
> > > Hannes,
> > >
> > > What specific network type(s) are you worried about?
> > >
> > > -Marc-
> > >
> > >
> > > On 8/10/10 8:25 AM, "Tschofenig, Hannes (NSN - FI/Espoo)"
> > > <hannes.tschofenig@nsn.com> wrote:
> > >
> > > > But the conclusion is missing: if you are on a shared link
> > > then you must
> > > > not share location at the level of the individual
> hosts. I fear that
> > > > those who implement and deploy would not get the point and would
> > > > nevertheless reveal information and put the user at risk.
> > > >
> > > >> -----Original Message-----
> > > >> From: ext Marc Linsner [mailto:mlinsner@cisco.com]
> > > >> Sent: Tuesday, August 10, 2010 3:23 PM
> > > >> To: Tschofenig, Hannes (NSN - FI/Espoo); geopriv@ietf.org
> > > >> Subject: Re: [Geopriv] draft-ietf-geopriv-rfc3825bis
> > > >>
> > > >> Hannes,
> > > >>
> > > >>
> > > >> On 8/10/10 3:33 AM, "Tschofenig, Hannes (NSN - FI/Espoo)"
> > > >> <hannes.tschofenig@nsn.com> wrote:
> > > >>
> > > >>> Hi all,
> > > >>>
> > > >>> during the GEOPRIV meeting I mentioned missing text in
> > > >>> draft-ietf-geopriv-rfc3825bis regarding security.
> > > >>>
> > > >>> DHCP does not provide confidentiality protection as a
> > > >> built-in feature.
> > > >>> As Marc mentioned in response to issue#23 (see
> > > >>> http://trac.tools.ietf.org/wg/geopriv/trac/ticket/23) every
> > > >> target would
> > > >>> be given the exact same location information on a
> shared medium.
> > > >>>
> > > >>> Unfortunately, the security consideration section does not
> > > >> mention this
> > > >>> aspect with a single word.
> > > >>
> > > >> Not true, currently in the security consideration section of
> > > >> the draft:
> > > >>
> > > >> " Since there is no privacy protection for DHCP messages, an
> > > >> eavesdropper who can monitor the link between the DHCP
> > > server and
> > > >> requesting client can discover this LCI."
> > > >>
> > > >> I don't believe more text is needed.
> > > >>
> > > >> -Marc-
> > > >>
> > > >>
> > > >>
> > > >>
> > > >>
> > > >>
> > > >> Hence, I suggest to add:
> > > >>>
> > > >>> "
> > > >>> Since there is no confidentiality protection for DHCP
> > > >> messages, an
> > > >>> eavesdropper who can monitor the link between the DHCP
> > > server and
> > > >>> requesting client can discover this LCI. In cases
> > > where multiple
> > > >>> hosts share the same link and can therefore see each
> > > others DHCP
> > > >>> messages the DHCP MUST NOT hand out location for
> > > individual hosts
> > > >>> but MUST rather provide location of the DHCP relay,
> > > DHCP server,
> > > >>> or a similar device instead. This ensures that
> none of the end
> > > >>> devices are able to learn exact information of the
> other hosts
> > > >>> on the same network.
> > > >>> "
> > > >>>
> > > >>> Ciao
> > > >>> Hannes
> > > >>>
> > > >>> _______________________________________________
> > > >>> Geopriv mailing list
> > > >>> Geopriv@ietf.org
> > > >>> https://www.ietf.org/mailman/listinfo/geopriv
> > > >>
> > > >>
> > > >>
> > >
> > >
> > >
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>
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Received on Tue, 17 Aug 2010 10:46:11 +0300

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