Re: [OAUTH-WG] Open Issues: Group Survey (respond by 5/13)

Yaron Goland <yarong@microsoft.com> Tue, 11 May 2010 23:24 UTC

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From: Yaron Goland <yarong@microsoft.com>
To: Torsten Lodderstedt <torsten@lodderstedt.net>
Thread-Topic: [OAUTH-WG] Open Issues: Group Survey (respond by 5/13)
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Date: Tue, 11 May 2010 23:23:51 +0000
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Cc: "OAuth WG (oauth@ietf.org)" <oauth@ietf.org>
Subject: Re: [OAUTH-WG] Open Issues: Group Survey (respond by 5/13)
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Actually it's server side that's the problem. Many servers limit the size of the HTTP request headers they will accept. Apache 2.2, for example, uses the LimitRequestFieldSize Directive (http://httpd.apache.org/docs/2.2/mod/core.html). Its default size is 8190 bytes. IIS, I Believe, defaults to around 16K. But SAML assertions can easily clock in at 30 or 40k without even trying.

So as a practical matter we need a way to allow clients to assert their right to a token using the request body so as to not need to artificially limit the size of the token that is being submitted.

		Yaron

> -----Original Message-----
> From: Torsten Lodderstedt [mailto:torsten@lodderstedt.net]
> Sent: Monday, May 10, 2010 10:47 PM
> To: Yaron Goland
> Cc: Eran Hammer-Lahav; OAuth WG (oauth@ietf.org)
> Subject: Re: [OAUTH-WG] Open Issues: Group Survey (respond by 5/13)
> 
> Am 11.05.2010 01:43, schrieb Yaron Goland:
> >
> >> ---
> >>
> >> 2. Client Authentication (in flows)
> >>
> >> How should the client authenticate when making token requests? The
> >> current draft defines special request parameters for sending client
> >> credentials. Some have argued that this is not the correct way, and
> >> that the client should be using existing HTTP authentication schemes
> >> to accomplish that such as Basic.
> >>
> >> A. Client authenticates by sending its credentials using special
> >> parameters (current draft) B. Client authenticated by using HTTP
> >> Basic (or other schemes supported by the server such as Digest)
> >>
> >>
> > [Yaron Goland] A is needed at a minimum because there are physical
> limitations to how many bytes can go into an authorization header.
> >
> 
> As far as I know, 4KB is the minimum size for headers that must be supported
> by user agents, which should suffice from my point of view.
> Moreover, other HTTP authentication mechanisms need much more than
> 4KB, For example, SPNEGO authentication headers can be up to 12392 bytes.
> 
> regards,
> Torsten.
> 
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> 
>