Re: [IPsec] Error in RFC6290

Hi

I agree with point #2. I'll leave it to some of the session resumption experts to comment on point #1.

It's a little late for "Merry Christmas", so just happy new year.

Yoav

-----Original Message-----
From: ipsec-bounces@ietf.org [mailto:ipsec-bounces@ietf.org] On Behalf Of Valery Smyslov
Sent: Wednesday, December 26, 2012 8:11 AM
To: ipsec@ietf.org
Subject: [IPsec] Error in RFC6290

Hi,

RFC6290 (Quick Crash Detection) contains an error. In Section 4.3 it states:

   For session resumption, as specified in [RFC5723], the situation is
   similar.  The responder, which is necessarily the peer that has
   crashed, SHOULD send a new ticket within the protected payload of the
   IKE_SESSION_RESUME exchange.  If the Initiator is also a token maker,
   it needs to send a QCD_TOKEN in a separate INFORMATIONAL exchange.

But IKE_SESSION_RESUME exchange, as specified in RFC5723, doesn't contain any protected payload - it is completely in clear and must be followed by IKE_AUTH exchange. I suspect this error came from early versions of IKE SA Resumption protocol that, as far as I remember, did contain protected payload. But currently this para should look like:

   For session resumption, as specified in [RFC5723], the situation is
   similar.  The responder, which is necessarily the peer that has
   crashed, SHOULD send a new ticket in IKE_AUTH exchange
   that immediately followed IKE_SESSION_RESUME exchange.
   If the Initiator is also a token maker, it needs to send a QCD_TOKEN in
   the same IKE_AUTH exchange.

And one more consideration. In Section 4.1 RFC6290 states:

   o  Protocol ID (1 octet) MUST be 1, as this message is related to an
      IKE SA.

   o  SPI Size (1 octet) MUST be zero, in conformance with Section 3.10
      of [RFC5996].

I think here we have contradiction with RFC5996 (despite clamed conformance with it). In abovementioned Section 3.10 it is written:

   o  Protocol ID (1 octet) - If this notification concerns an existing
      SA whose SPI is given in the SPI field, this field indicates the
      type of that SA.  For notifications concerning Child SAs, this
      field MUST contain either (2) to indicate AH or (3) to indicate
      ESP.  Of the notifications defined in this document, the SPI is
      included only with INVALID_SELECTORS and REKEY_SA.  If the SPI
      field is empty, this field MUST be sent as zero and MUST be
      ignored on receipt.

Let me emphasize that RFC5996 clearly requires that If the SPI field is empty, Protocol ID field MUST be sent as zero and MUST be ignored on receipt, but RFC6290 while requiring SPI field to be empty, requres Protocol ID field to be non-zero. Actually, I see no value in this requirement, as Protocol ID MUST be ignored on receipt anyway (if SPI field is empty), so it just complicates protocol and makes it cumbersome.

Merry Christmas,
Valery Smyslov.

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