[Gen-art] Gen-art last call review of draft-ietf-tls-multiple-cert-status-extension-04

[Elwyn Davies <[e-mail]>]

I am the assigned Gen-ART reviewer for this draft. For background on
Gen-ART, please see the FAQ at

<http://wiki.tools.ietf.org/area/gen/trac/wiki/GenArtfaq>.

Please resolve these comments along with any other Last Call comments
you may receive.

Document: draft-ietf-tls-multiple-cert-status-extension-04.txt
Reviewer: Elwyn Davies
Review Date: 22 March 2013
IETF LC End Date: 29 March 2013
IESG Telechat date: (if known) -

Summary: Almost ready for IESG - one possible minor issue relating to 
the alleged criterion for ordering CertificateStatusRequestItems plus a 
number of nits that are mainly missing cross references and notes for 
clarity about updates of RFC 6066 items.

Major issues:
None

Minor issues:
s2.2:
>     The list of CertificateStatusRequestItem entries MUST be in order of
>     preference.
Having thought a bit about this, I cannot identify what the preference 
criterion is - this may be because I don't understand the problem, but I 
think you need to explain what the criterion is if there really is one.  
If there *is* a criterion, it must be clear whether the order is most 
preferred first or least preferred first. Since I don't know what the 
criterion is, I can't tell if there are any security implications from 
the ordering: no chance of downgrade attacks?

Nits/editorial comments:
s2:
The presentation format used should be referenced back to s4 of RFC 5246.

s2.1:
A reference to s1.1 of RFC 6066 where extension_type is defined is 
needed, and it should be made more clear that this an expansion of the 
existing type.

s2.2:
A reference to s7.4.1.4 of RFC 5246 where extension_data is defined is 
needed.

s2.2, page 4:
Might be good to be more explicit that the definition of 
CertificateStatusRequest is an extension of the definition in RFC 6066.  
Also the definition of OSCPStatusRequest duplicates the one in RFC 6066 
and should be noted as such.  It would also be more appropriate if it 
came before CertificateStatusRequest as it is used in 
CertificateStatusRequest.

s2.2, para 4 on page 5:
>     In the case of the "id-pkix-ocsp-nonce" OCSP extension, [RFC2560  <http://tools.ietf.org/html/rfc2560>] is
>     unclear about its encoding; for clarification,.....
This probably needs to be flagged up in the IANA considerations so that 
an additional reference is added to the registry.
ALSO I subsequently noted that this same caveat is already in RFC 6066.  
Consider referring to the caveat there rather than duplicating it.

s2.2, para 5 on page 5:
s/A server that receive a client hello/A server that receives a client 
hello/

s2.2, page 5/6:
Might be good to be more explicit that the definition of 
CertificateStatus is an extension of the definition in RFC 6066.
Also the definition of OSCPResponse duplicates the one in RFC 6066 and 
should be noted as such.  It would also be more appropriate if it came 
before CertificateStatus as it is used in CertificateStatus.

s2.2, page 6:
The definition of OCSPResponseList should come before the redefinition 
of CertificateStatus as it is used in CertificateStatus.

s2.2, para 2 after structure definitions on page 6:
A reference to s7.4.2 of RFC 5246 for the Certificate list would be helpful.