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Re: Accountability in AC4CSR

From: Anne van Kesteren <annevk@opera.com>
Date: Thu, 14 Feb 2008 11:58:09 +0100
To: jpanzer@acm.org
Cc: "Ian Hickson" <ian@hixie.ch>, "WAF WG (public)" <public-appformats@w3.org>
Message-ID: <op.t6igq7ey64w2qv@annevk-t60.oslo.opera.com>

On Thu, 14 Feb 2008 06:59:29 +0100, John Panzer <jpanzer@acm.org> wrote:
> Anne van Kesteren wrote:
>> This is currently not the case for XMLHttpRequest level 2. Based on  
>> feedback from Mozilla only Accept and Accept-Language can be set for  
>> cross-site requests.
>
> (Aside: Surely Content-Type is allowed as well?)

Currently, no.


> This rules out the use of AtomPub's (RFC5023)  If-Match: header on PUT  
> for optimistic concurrency control, and the Slug: header[1] on POSTs for  
> suggesting the URI to mint.  The first is especially troublesome.
>
> It also eliminates the ability to do cache control (except crudely by  
> salting the URL, which of course fills up caches with dead data).   It  
> makes it impossible to use the common X-Method-Override work-around for  
> intermediaries which don't support things other than GET and POST.  It  
> prevents the use of the Range: header to get a subset of a resource.   
> And of course it prevents the use of any custom X- header for any  
> purpose.

I agree that it provides a lot of limitations. I believe the primary  
concern is not provide new attack vectors. GET requests you can currently  
issue don't allow setting of custom headers, for instance. However, this  
concern does not apply to POST/PUT, etc. as there you make an initial  
request to see if the server is ok with it.

Jonas?


-- 
Anne van Kesteren
<http://annevankesteren.nl/>
<http://www.opera.com/>
Received on Thursday, 14 February 2008 10:54:30 GMT

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