It's my understanding that the general assertions claim is more of a conceptual 
mapping than it is a concrete encoding, so anything more specific here would be 
out of place. I would like the authors to either confirm or correct my 
assumptions, though.

 -- Justin


On Jan 11, 2013, at 6:30 AM, Stephen Farrell <[email protected]>
 wrote:

> 
> Hi,
> 
> Since we thought we were done with it, I put this document
> on the IESG telechat agenda for Jan 24. Hannes' question
> however looks like its a real one that needs an answer.
> 
> I'd appreciate it if the WG could figure out if there's any
> change needed and either make that change in the next week,
> or else tell me to take the draft off the telechat agenda
> for now.
> 
> If discussion doesn't happen, or happens but doesn't reach
> a conclusion, then I'll take the draft off the agenda in a
> week's time and we can sort out if any changes are needed
> later.
> 
> The reason why now+1-week matters, is that that's when
> IESG members tend to do their reviews and having 'em all
> review a moving target isn't a good plan.
> 
> Thanks,
> S.
> 
> On 01/11/2013 08:18 AM, Hannes Tschofenig wrote:
>> Hi guys, 
>> 
>> Thanks for updating the assertion document and for incorporating the 
>> comments received on the mailing list. 
>> 
>> There is only one issue that caught my attention. You changed the 
>> description of the audience element to the following text (in version -09 of 
>> http://tools.ietf.org/html/draft-ietf-oauth-assertions-09):
>> "
>>   Audience  A value that identifies the parties intended to process the
>>      assertion.  An audience value MAY be the URL of the Token Endpoint
>>      as defined in Section 3.2 of OAuth 2.0 [RFC6749].
>> "
>> 
>> Since the value in the audience field is used to by the authorization server 
>> in a comparison operation (see Section 5.2) I believe the current text will 
>> lead to interoperability problems. Not only is the comparision operation 
>> unspecified but even the value that is contained in the field is left open. 
>> The RFC 2119 MAY does not really give a lot of hints of what should be put 
>> in there. 
>> 
>> Without having a clear description of what identifier is contained in this 
>> field and how the comparison works it is either possible that a legitimate 
>> client is rejected by the authorization server (which is annoying) or an 
>> assertion with an incorrect assertion is accepted (which is a security 
>> problem). 
>> 
>> Btw, the same issue can also be seen in 
>> http://tools.ietf.org/html/draft-ietf-oauth-jwt-bearer-04, 
>> http://tools.ietf.org/html/draft-ietf-oauth-saml2-bearer-15 and in a more 
>> generic form also in the JWT (Section 4.1.3 of 
>> http://tools.ietf.org/html/draft-ietf-oauth-json-web-token-06; "aud" claim). 
>> From the description in the JWT document I was not quite sure whether the 
>> ability to carry an array of case sensitive strings for that field is also 
>> allowed in any of the assertion documents. 
>> 
>> Note that there are two documents that provide input to this problem space, 
>> namely:
>> http://tools.ietf.org/html/rfc6125
>> http://tools.ietf.org/html/draft-iab-identifier-comparison-07
>> 
>> So, I would suggest to decide what type of identifier goes into this field 
>> and then to point to a document that illustrates how the comparison 
>> operation would look like. Possible identifiers are domain names, IP 
>> addresses, URIs, etc. Just as an example from RFC 6125 would you allow a 
>> wildcard match (like "*.example.com") or only an equality match? Would 
>> "www.example.com" be the same as "example.com" if they resolve to the same 
>> IP address(es)?
>> 
>> Ciao
>> Hannes
>> 
>> _______________________________________________
>> OAuth mailing list
>> [email protected]
>> https://www.ietf.org/mailman/listinfo/oauth
>> 
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