Re: [IPsec] AD review: draft-nir-ipsecme-erx-04.txt
Yoav Nir writes: > > 0) Overall: A couple of folks that I mentioned this to asked: is anybody > > really doing ERP? So I'm just curious if they are. This obviously > > non-blocking. > > My guess is that it is not widely deployed, because 802.1x is for > now not widely deployed. EAP is used in some other contexts, like > L2TP VPN clients and cable modem/ADSL dialers, but those don't tend > to need support for roaming. EAP-RP also got just added to the IEEE 802.11ai (fast initial link setup) specification framework document, so support for it should be coming to the 802.11 networks in the future. That might allow things like moving from the company WLAN to the VPN over 3G or similar. On the other hand you might still want to run VPN over the WLAN too... > > 1) General: In case people missed it, the first EAP message for ERX is > > moved to the initial IKE_AUTH request. I haven't seen any objections to > > this but I'd like to make sure implementers are okay with this!? > > > > Maybe it's splitting hairs but could you do the following to maintain > > architectural integrity/purity (i.e., not mix them): > > > >first request --> EAP(EAP_Initiate/Re-auth), > > > > be this: > > > >first request --> N[EAP(EAP_Initiate/Re-auth)], > > > > I guess you could do the same thing for the first response. > > The responder has indicated support for ERX in the Initial exchange > response, so it is expecting to get an EAP message in the first > IKE_AUTH request. I guess architectural integrity is a matter of > taste, but to me it seems that EAP messages should go in EAP > payloads rather than Notify payloads. I agree on that. We have EAP payload to transmit EAP payloads and we should keep that for it... I do not see any problems having EAP payload in the first IKE_AUTH request, as it is negotiated beforehand. I.e. server who did send N(ERX_SUPPORTED) do know how to process it there. > > 12) s5: I think you did a good job explaining protecting the clients > > identity. Can you add some more text about exposing the servers > > identity first and why you don't think it's a problem? > > The KeyName-NAI TLV sent in the IDi payload should be meaningful > enough to the Authenticator to be able to look up the true identity > of the client, so here, as in regular IKE, the initiator goes first. > It's true that for an active MitM, only the server reveals its > identity, as opposed to both client and server, but that is a good > thing, no? I assume you mean that the client ID that is releaved to the active MitM attacker is that ephemeral username, so it is no use for attacker? I assume that ephemeral username is still sent in the IKE EAP packet without any other encryption than normal IKEv2 packet encryption, thus it is visible to the active MitM attacker. > How about: >With this variant of the IKEv2 protocol, the initiator never sends its >identity on the wire, while the server does. An active attacker could >get the server identity from the exchange, but not the user identity. >In regular IKE, both the user and gateway identities are exposed to an >active attacker. I would replace /its identity on the wire/its real identity on the wire (only ephemeral identity is transmitted)/. -- kivi...@iki.fi ___ IPsec mailing list IPsec@ietf.org https://www.ietf.org/mailman/listinfo/ipsec
Re: [IPsec] AD review: draft-nir-ipsecme-erx-04.txt
Yoav, Response inline. After posting a new version, just find a non-author shepherd to do a write-up and get it me and we'll be off to the races. spt On 7/10/12 9:35 AM, Yoav Nir wrote: Hi Sean Thanks for the review. My answers are inline. Yoav On Jul 3, 2012, at 2:17 AM, Sean Turner wrote: Yoav asked me to do an AD review of draft-nir-ipsecme-erx. We agreed that it'd be all right for me to send my comments here. They are as follows: 0) Overall: A couple of folks that I mentioned this to asked: is anybody really doing ERP? So I'm just curious if they are. This obviously non-blocking. My guess is that it is not widely deployed, because 802.1x is for now not widely deployed. EAP is used in some other contexts, like L2TP VPN clients and cable modem/ADSL dialers, but those don't tend to need support for roaming. ack - thanks for the info. 1) General: In case people missed it, the first EAP message for ERX is moved to the initial IKE_AUTH request. I haven't seen any objections to this but I'd like to make sure implementers are okay with this!? Maybe it's splitting hairs but could you do the following to maintain architectural integrity/purity (i.e., not mix them): first request --> EAP(EAP_Initiate/Re-auth), be this: first request --> N[EAP(EAP_Initiate/Re-auth)], I guess you could do the same thing for the first response. The responder has indicated support for ERX in the Initial exchange response, so it is expecting to get an EAP message in the first IKE_AUTH request. I guess architectural integrity is a matter of taste, but to me it seems that EAP messages should go in EAP payloads rather than Notify payloads. Nobody else seems bothered by this so I'll let this go. 2) expand AAA on first use Last paragraph of section 2. OK, will do. ack 3) s3 contains the following: This Notify replaces the EAP-Initiate/Re-auth-Start message of ERX, and therefore contains the domain name, as specified in section 5.3.1.1 of [RFC5296bis]. Is "replaces" the right word here? I think what you're saying is that the Notify serves the same purpose as the ERX EAP-Initiate/Re-auth-Start message? I went to 5.3.1.1 and I think what you're really pointing to is the Domain-Name in 5.3.1, which is an NAI from [RFC4282]? Maybe switch the pointer to 5.3.1. Right about the "replace". Section 5.3.1.1 talks about the authenticator operation (sending the EAP-Initiate/Re-auth-Start message and including the domain name TLV), so it seemed appropriate. On the other hand 5.3.1 contains the format of the EAP message, which is different from that of the IKEv2 Notify payload. How about: This Notify serves the same purpose as the EAP-Initiate/Re-auth-Start message of ERX, as specified in section 5.3.1 or [RFC5296bis]. The domain name included in the payload is the same as that included in the Domain-Name TLV as specified in section 5.3.1.1 or the same document. that'll work 4) s3: In the intro to the protocol exchanges it says most of the optional bits are omitted, but that seems to only be true in the IKE_SA_INIT exchanges. Could the IKE_AUTH exchanged be trimmed down to (and depending on comment 0 the first line gets changed too): first request --> EAP(EAP_Initiate/Re-auth), IDi, SA, TSi, TSr, first response <-- IDr, AUTH, EAP(EAP-Finish/Re-auth), last request--> AUTH last response <-- AUTH, SA, TSi, TSr, Just curious if those optional fields aren't so optional anymore. You're right. I will, however leave the CERT payload in there, so as not to have this imply that we're not using certs anymore (we're not requiring RFC 5998 compliance) ack 5) s3: Do you think the following would help the not so plugged in reader to add the following to the figure of the exchanges: IKE_SA_INIT +- |init request --> SA, KE, Ni, | | | |init response <-- SA, KE, Nr, +- N[ERX_SUPPORTED] IKE_AUTH Exchange with EAP +- |first request --> EAP(EAP_Initiate/Re-auth), |IDi, |SA, TSi, TSr, | |first response <-- IDr, AUTH, |EAP(EAP-Finish/Re-auth), | |last request--> AUTH | |last response <-- AUTH, |SA, TSi, TSr, +- I guess so. I'll add headlines next version. ack 6) s3/6: Don't you have to register the Identification Payload type in IKEv2 Identification Payload ID Types? I don't think so. ID_RFC822_ADDR is already registered, and that is the format of the KeyName-NAI. ack 7) s3.1: I think you need to be clear that the codes 5 and 6 came from RFC 5296: r/(5 and 6)/(5 and 6) [RFC5296] and maybe: r/or i
Re: [IPsec] AD review: draft-nir-ipsecme-erx-04.txt
Hi Sean Thanks for the review. My answers are inline. Yoav On Jul 3, 2012, at 2:17 AM, Sean Turner wrote: > Yoav asked me to do an AD review of draft-nir-ipsecme-erx. We agreed > that it'd be all right for me to send my comments here. They are as > follows: > > 0) Overall: A couple of folks that I mentioned this to asked: is anybody > really doing ERP? So I'm just curious if they are. This obviously > non-blocking. My guess is that it is not widely deployed, because 802.1x is for now not widely deployed. EAP is used in some other contexts, like L2TP VPN clients and cable modem/ADSL dialers, but those don't tend to need support for roaming. > 1) General: In case people missed it, the first EAP message for ERX is > moved to the initial IKE_AUTH request. I haven't seen any objections to > this but I'd like to make sure implementers are okay with this!? > > Maybe it's splitting hairs but could you do the following to maintain > architectural integrity/purity (i.e., not mix them): > >first request --> EAP(EAP_Initiate/Re-auth), > > be this: > >first request --> N[EAP(EAP_Initiate/Re-auth)], > > I guess you could do the same thing for the first response. The responder has indicated support for ERX in the Initial exchange response, so it is expecting to get an EAP message in the first IKE_AUTH request. I guess architectural integrity is a matter of taste, but to me it seems that EAP messages should go in EAP payloads rather than Notify payloads. > 2) expand AAA on first use Last paragraph of section 2. OK, will do. > 3) s3 contains the following: > > This Notify replaces the EAP-Initiate/Re-auth-Start message of ERX, > and therefore contains the domain name, as specified in section > 5.3.1.1 of [RFC5296bis]. > > Is "replaces" the right word here? I think what you're saying is that > the Notify serves the same purpose as the ERX EAP-Initiate/Re-auth-Start > message? > > I went to 5.3.1.1 and I think what you're really pointing to is the > Domain-Name in 5.3.1, which is an NAI from [RFC4282]? Maybe switch the > pointer to 5.3.1. Right about the "replace". Section 5.3.1.1 talks about the authenticator operation (sending the EAP-Initiate/Re-auth-Start message and including the domain name TLV), so it seemed appropriate. On the other hand 5.3.1 contains the format of the EAP message, which is different from that of the IKEv2 Notify payload. How about: This Notify serves the same purpose as the EAP-Initiate/Re-auth-Start message of ERX, as specified in section 5.3.1 or [RFC5296bis]. The domain name included in the payload is the same as that included in the Domain-Name TLV as specified in section 5.3.1.1 or the same document. > 4) s3: In the intro to the protocol exchanges it says most of the > optional bits are omitted, but that seems to only be true in the > IKE_SA_INIT exchanges. Could the IKE_AUTH exchanged be trimmed down to > (and depending on comment 0 the first line gets changed too): > > first request --> EAP(EAP_Initiate/Re-auth), > IDi, > SA, TSi, TSr, > > first response <-- IDr, AUTH, > EAP(EAP-Finish/Re-auth), > > last request--> AUTH > > last response <-- AUTH, > SA, TSi, TSr, > > Just curious if those optional fields aren't so optional anymore. You're right. I will, however leave the CERT payload in there, so as not to have this imply that we're not using certs anymore (we're not requiring RFC 5998 compliance) > 5) s3: Do you think the following would help the not so plugged in > reader to add the following to the figure of the exchanges: > > IKE_SA_INIT >+- >|init request --> SA, KE, Ni, >| >| >| >|init response <-- SA, KE, Nr, >+- N[ERX_SUPPORTED] > > IKE_AUTH Exchange with EAP >+- >|first request --> EAP(EAP_Initiate/Re-auth), >|IDi, >|SA, TSi, TSr, >| >|first response <-- IDr, AUTH, >|EAP(EAP-Finish/Re-auth), >| >|last request--> AUTH >| >|last response <-- AUTH, >|SA, TSi, TSr, >+- I guess so. I'll add headlines next version. > 6) s3/6: Don't you have to register the Identification Payload type in > IKEv2 Identification Payload ID Types? I don't think so. ID_RFC822_ADDR is already registered, and that is the format of the KeyName-NAI. > 7) s3.1: I think you need to be clear that the codes 5 and 6 came from > RFC 5296: > > r/(5 and 6)/(5 and 6) [RFC5296] > > and maybe: > > r/or in this document/or in [RFC5296] To clarify, an implementation supporting this specification MUST accept and transmit EAP messages with at least the codes for Initiate an
