Hi Yaron,
oh, you've catched one more error in this text - it mixed up terms "ticket"
(used in RFC5723 as Session Resumption ticket) and "token"
(used in RFC6290 as QCD token). I din't notice that. You are right,
that "ticket" (Session Resumption) is sent in IKE_SESSION_RESUME,
but RFC6290 talks where QCD token must be sent. And from my understanding
of the whole protocol it must not be sent in clear under any circumstances
(otherwise eavesdropper can easily tear down IKE SA), so the only logical
place for it in case of IKE SA resumption is IKE_AUTH exchange
that immediately follows IKE_SESSION_RESUME. So, I think,
correct text should be:
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 QCD_TOKEN in IKE_AUTH exchange
that immediately followes 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.
Best wishes,
Valery.
Hi Yoav, Valery,
Valery is right that the IKE_SESSION_RESUME exchange does not have a protected
payload.
But his new text is incorrect, since the (session resumption) ticket is sent in IKE_SESSION_RESUME
and not in the immediately following IKE_AUTH (he might have got it mixed with the ticket sent
when *requesting* a ticket). So I guess we should just replace "within the protected payload of
the IKE_SESSION_RESUME exchange" by "within the IKE_SESSION_RESUME exchange".
According to http://en.wikipedia.org/wiki/Christmas#Listing, it's still more than a week until the
Eastern Churches' Christmas. So Merry Christmas to some of us, and a Happy New Year to all.
Thanks,
Yaron
On 12/26/2012 10:42 AM, Yoav Nir wrote:
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-boun...@ietf.org [mailto:ipsec-boun...@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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