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

From: James M. Polk ^lt;jmpolk@cisco.com>
Date: Mon Aug 16 2010 - 16:37:51 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.

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.

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.

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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Received on Mon, 16 Aug 2010 15:37:51 -0500

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