RE: clarification on IKEv2 with EAP

["William Dixon" <ietf-wd@v6security.com>]

David, is your situation also one where the path of EAP payloads originates
and terminates on the same hosts that IKEv2 ISAKMP SA does ? I'd think that
many uses of EAP will end up decapsulating it out of IKEv2 on the VPN
gateway & carrying it through Radius to the authentication server - in which
case EAP's protections are needed for its entire path.

> -----Original Message-----
> From: owner-ipsec@lists.tislabs.com 
> [mailto:owner-ipsec@lists.tislabs.com] On Behalf Of David 
> Mariblanca (ML/EEM)
> Sent: Thursday, April 01, 2004 11:13 AM
> To: 'Tschofenig Hannes'; 'Pasi.Eronen@nokia.com'; 
> ipsec@lists.tislabs.com
> Subject: RE: clarification on IKEv2 with EAP
> 
> 
> Hi,
> well, I am not specially worried about that, but rather to 
> implement extra protections when it's not needed. The EAP 
> methods I am now thinking about are EAP SIM and EAP AKA, 
> which already provide some protection mechanisms. If IKEv2, 
> on top of that, gives integrity and encryption to the EAP 
> messages, maybe we will spend unnecessary resources when 
> using EAP SIM/AKA over IKEv2, if we consider that either 
> IKEv2 or EAP SIM/AKA levels of protection are secure enough.
> But I guess other EAP methods do not provide the same level 
> of protection and that's why IKEv2 has to be designed in 
> order to not depend on EAP implementations.
> 
> In the other hand, after reading your paper (the one you are 
> writing with Pasi) I see very reasonable your proposal to 
> omit AUTH in message 4: if IKEv2 says that in messages 7 and 
> 8 the AUTH payloads will protect messages 1 and 2 
> (respectively), why to send AUTH in message 4 ? Does message 
> 2 need to be authenticated twice ?
> 
> Cheers,
> David.
> 
> -----Original Message-----
> From: Tschofenig Hannes [mailto:hannes.tschofenig@siemens.com]
> Sent: jueves, 01 de abril de 2004 17:31
> To: David Mariblanca (ML/EEM); 'Pasi.Eronen@nokia.com'; 
> ipsec@lists.tislabs.com
> Subject: RE: clarification on IKEv2 with EAP
> 
> 
> hi david, 
> 
> i am only curious: 
> why do you worry about the protection of eap messages? 
> 
> ciao
> hannes
> 
> 
> > Ok, I see. I did not remember the EAP messages were already 
> integrity 
> > protected and encrypted with Sk_a and Sk_e. Then the AUTH payloads 
> > protect the IKE_INIT messages, the ones which were not sent 
> protected 
> > since there was not key material yet to do it, correct ?
> > 
> > 
> > -----Original Message-----
> > From: Pasi.Eronen@nokia.com [mailto:Pasi.Eronen@nokia.com]
> > Sent: jueves, 01 de abril de 2004 13:19
> > To: David Mariblanca (ML/EEM); ipsec@lists.tislabs.com
> > Subject: RE: clarification on IKEv2 with EAP
> > 
> > 
> > 
> > David Mariblanca wrote:
> > 
> > > I will give my interpretation of  chapter 16 and please confirm 
> > > if it is correct.
> > > - The EAP payloads are sent in the IKEv2 messages without 
> > > AUTH payloads. The AUTH payloads are sent only in the last 
> > > two IKEv2 messages, and they correspond to the last two EAP 
> > > messages, that is, AUTH in message 7 to EAP payload in 
> > > message 5, and AUTH in message 8 to EAP payload in message 6
> > 
> > No, AUTH payloads do not authenticate the EAP messages, they
> > authenticate the IKEv2 SA (basically information from the 
> > first two IKEv2 messages; first paragraph of Section 2.15 
> > explains exactly what is included in the "<message octets>").
> > 
> > (All EAP messages are also MAC'd with SK_ar/SK_ai, but this is 
> > not related to AUTH payloads; the integrity protection is 
> > included in the "SK{...}" notation).
> > 
> > Best regards,
> > Pasi
> > 
> 
>