Re: [users@httpd] proxy and chunk mode

"William A. Rowe, Jr." <wrowe@xxxxxxxxxxxxx> · Mon, 10 Oct 2005 10:36:27 -0500

david micheneau wrote:

I’ve a trouble with the chunk mode connection pass through a proxy.

It seems that the content-length is not forwarded when you use chunk 

mode via a proxy mode: CHANGE-LOG in :

Uhmmm... most of the time it was never there...

*) SECURITY: CAN-2005-2088 (cve.mitre.org)
     proxy: Correctly handle the Transfer-Encoding and Content-Length
     headers.  *Discard the request Content-Length whenever T-E: chunked*

     is used, always passing one of either C-L or T-E: chunked whenever 

     the request includes a request body.  Resolves an entire class of

     proxy HTTP Request Splitting/Spoofing attacks.  [William Rowe]

But now, how we treat a http request, if we don’t know the content 

length via proxy mode ?

Transfer-Encoding: chunked.

All HTTP/1.1 servers and clients are required to support that method.
And HTTP/1.1 servers and clients are required to ignore any
Content-Length: header if Transfer-Encoding: chunked is present.

May be a noob question but: Why Apache doesn’t calculate the 

content-length himself before to send via the proxy handler ?

It will, for HTTP/1.0 servers.

Care to provide details of a specific problem you are observing?

Bill

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