[jose] JWK member names, was: SECDIR review of draft-ietf-jose-json-web-key-31

Hi Mike,

The text Steve called out below has been very problematic as you know.
 Could you call out some options here as the last time this came up, we
didn't resolve it.  The working group was asked for suggestions, but none
came through.  If you could provide some options and then have the working
group weigh in, I think that would be good.

I snipped away the rest of the review and changed the subject as not to get
in the way of the current dialog.

Thanks.

On Wed, Sep 10, 2014 at 8:57 PM, Mike Jones <Michael.Jones@microsoft.com>
wrote:

>  Hi Stephen.  Thanks for your detailed and useful review.  I’ve cc’ed the
> working group in my reply so they’re aware of the contents of your review.
> Replies are inline below…
>
>
>
> *From:* Stephen Kent [mailto:kent@bbn.com <kent@bbn.com>]
> *Sent:* Tuesday, September 02, 2014 1:09 PM
> *To:* secdir@ietf.org; Mike Jones; jose-chairs@tools.ietf.org; Moriarty,
> Kathleen
> *Subject:* SECDIR review of draft-ietf-jose-json-web-key-31
>
>
>
> [snip]

>
>
> This section imposes a rather wimpy constraint on parameter names:
>
>
>
>    The member names within a JWK MUST be unique; recipients MUST either
>
>    reject JWKs with duplicate member names or use a JSON parser that
>
>    returns only the lexically last duplicate member name, as specified
>
>    in Section 15.12 (The JSON Object) of ECMAScript 5.1 [ECMAScript].
>
>
>
> This text says that member names MUST be unique, but if they are not,
> that’s OK too; just use the last instance of a member with a duplicate
> name. This seems like a terrible design principle. It imposes what appears
> to be a requirement, then says how to accommodate data structures that fail
> to meet the requirement. This would seem to encourage sloppy
> implementations (for JWK generation). I’d like to see the rationale for
> this.
>
>
>
>
>
> Unfortunately, the intentional laxness in the spec in this regard is a
> reflection of the semantics of the actual JSON specifications and
> implementations.  For instance,
> http://tools.ietf.org/html/rfc7159#section-4 says:
>
>
>
>    An object whose names are all unique is interoperable in the sense
>
>    that all software implementations receiving that object will agree on
>
>    the name-value mappings.  When the names within an object are not
>
>    unique, the behavior of software that receives such an object is
>
>    unpredictable.  Many implementations report the last name/value pair
>
>    only.  Other implementations report an error or fail to parse the
>
>    object, and some implementations report all of the name/value pairs,
>
>    including duplicates.
>
>
>
> This topic has been heavily discussed by the working group, and while the
> specs used to just say that objects with duplicate member names MUST be
> rejected, working group members, including Tim Bray (the editor of the JSON
> spec), prevailed on us to weaken this so that parsers that implement the
> ECMAscript behavior of returning only the last member name may be legally
> used.  (The argument was made that there was more security downside in
> effectively requiring people to write and debug their own strict parsers
> than in using laxer, but well-supported and debugged parsers.)
>
>
>
> However, we also intentionally require that producers use only one
> instance of each member name, so that legally produced objects will never
> exercise the ambiguities that are present in real JSON parsers.  That
> seemed to be the most practical solution to the working group.
>
>
>
> [snip]
>
>                                                             Thanks again,
> Stephen,
>
>                                                             -- Mike
>
>
>
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>
>

-- 

Best regards,
Kathleen

-- 

Best regards,
Kathleen