Commit 6857b46a authored by dgaudet's avatar dgaudet
Browse files

This patch removes the processing of `mxb' parameters in Accept 

headers in mod_negotiation.  A second patch updates the manual to
reflect this (mxb is not documented directly in the manual but support
for it is implied in one place).

Reasons for removing this feature:

1) As currently implemented, the 'mxb' feature makes possible certain
denial-of-service attacks on negotiated content.  These attacks are
posssible for user communities which access an Apache server from
behind a HTTP/1.1 proxy which implements `Vary' related optimisations.
Plugging this denial of service hole without removing `mxb' is fairly
expensive in terms of degrading caching efficiency.

2) `mxb' is not in HTTP/1.0 or HTTP/1.1 or any other standard

3) Nobody seems to make use of 'mxb'.  (Balachander Krishnamurthy
kindly offered to grep some of his web traffic traces -- he did not
find a single Accept with mxb in a whole day of recent traffic, nor in
older traces)

4) Removing a feature makes a nice change from adding features.

Submitted by:	Koen Holtman <Koen.Holtman@cern.ch>


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@83288 13f79535-47bb-0310-9956-ffa450edef68
parent 118c18dd

docs/manual/content-negotiation.html

+3 −4
Original line number Diff line number Diff line
@@ -196,10 +196,9 @@ The full list of headers recognized is: 
       for compress'd files, and <CODE>x-gzip</CODE> for gzip'd files.

       The <CODE>x-</CODE> prefix is ignored for encoding comparisons.

  <DT> <CODE>Content-Length:</CODE>

  <DD> The size of the file.  Clients can ask to receive a given media

       type only if the variant isn't too big; specifying a content

       length in the map allows the server to compare against these

       thresholds without checking the actual file.

  <DD> The size of the file.  Specifying content

       lengths in the type-map allows the server to compare file sizes

       without checking the actual files.

  <DT> <CODE>Description:</CODE>

  <DD> A human-readable textual description of the variant.  If Apache cannot

       find any appropriate variant to return, it will return an error

docs/manual/content-negotiation.html.en

+3 −4
Original line number Diff line number Diff line
@@ -196,10 +196,9 @@ The full list of headers recognized is: 
       for compress'd files, and <CODE>x-gzip</CODE> for gzip'd files.

       The <CODE>x-</CODE> prefix is ignored for encoding comparisons.

  <DT> <CODE>Content-Length:</CODE>

  <DD> The size of the file.  Clients can ask to receive a given media

       type only if the variant isn't too big; specifying a content

       length in the map allows the server to compare against these

       thresholds without checking the actual file.

  <DD> The size of the file.  Specifying content

       lengths in the type-map allows the server to compare file sizes

       without checking the actual files.

  <DT> <CODE>Description:</CODE>

  <DD> A human-readable textual description of the variant.  If Apache cannot

       find any appropriate variant to return, it will return an error