RE: [wss] ISSUE 190: text for SOAP MustUnderstand issue

["Reid, Irving" <irving.reid@hp.com>]

I think the wording Chris sent is great; I've hacked up his messages below to get it all in one place.

The one point that remains sticky is the final paragraph, dealing with non-mandatory headers. I'd like to get a firm decision from the TC on what semantics we desire when a <wsse:Security> header block is not mandatory. As I see it, the two options are:

1) All or nothing. If a conforming implementation does not recognize every element and attribute within the non-mandatory header block, it MUST NOT process any of the content in the header block.

2) Best effort. If a conforming implementation does not recognize every element and attribute within the non-mandatory header block, it MAY process only the portions it recognizes.


I can't resist the aside:

> > The SOAP mustUnderstand attribute with a value of true does not 
> > mean "ignore at your own peril", it is an integral part of the 
> > SOAP protocol.

I agree. However, X509 (and lots of other examples) have taught us that implementers sometimes ignore these things anyway. In my opinion, best practice is to design, code and contract defensively so that, when possible, senders are not compromised when receivers violate the specification.

 - irving - 

From: Christopher B Ferris [mailto:chrisfer@us.ibm.com]
>     Conforming implementations are said to "understand" a
>     <wsse:Security> header block if they are able to process the 
>     <wsse:Security> header block and all of its descendant elements,
>     including any elements or attributes defined by profiles 
>     or extensions.
>
>     If a <wsse:Security> header block is marked as mandatory by
>     means of a SOAP mustUnderstand attribute, and also contains 
>     extension elements or attributes that are not recognized 
>     by the SOAP node to which the <wsse:Security> header block is
>     targetted, a conforming implementation MUST generate a 
>     SOAP MustUnderstand fault. 
>
>     If a <wsse:Security> header block is not marked as mandatory
>     by means of a SOAP mustUnderstand attribute, and also contains
>     extension elements or attributes that are not recognized by the
>     SOAP node to which the <wsse:Security> header block is targetted,
>     a conforming implementation MAY choose not to process the 
>     <wsse:Security> header block.