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Posted to bugs@httpd.apache.org by bu...@apache.org on 2012/04/29 14:43:38 UTC
[Bug 53160] New: Reverse Proxy mod_deflate doesn't zip back content
in outgoing traffic
https://issues.apache.org/bugzilla/show_bug.cgi?id=53160
Priority: P2
Bug ID: 53160
Assignee: bugs@httpd.apache.org
Summary: Reverse Proxy mod_deflate doesn't zip back content in
outgoing traffic
Severity: normal
Classification: Unclassified
OS: Linux
Reporter: alevy@salesforce.com
Hardware: PC
Status: NEW
Version: 2.2.3
Component: mod_deflate
Product: Apache httpd-2
When working with httpd in reverse proxy mode,
mod_deflate doesn't zip back content in outgoing traffic.
The usual configuration of mod_deflate is rather simple, but doesn't cover
reverse proxy cases:
SetOutputFilter INFLATE
SetInputFilter DEFLATE
This bug was investigated with mod_dumpio.
When incoming http traffic from client contains "content-encoding" in http
header:
dumpio_in (data-TRANSIENT): 37 bytes
dumpio_in (data-TRANSIENT): POST /services/Soap/u/24.0 HTTP/1.1\r\n
dumpio_in [getline-blocking] 0 readbytes
dumpio_in (data-TRANSIENT): 24 bytes
dumpio_in (data-TRANSIENT): Content-Encoding: gzip\r\n
dumpio_in [getline-blocking] 0 readbytes
dumpio_in (data-TRANSIENT): 23 bytes
dumpio_in (data-TRANSIENT): Accept-Encoding: gzip\r\n
dumpio_in [getline-blocking] 0 readbytes
dumpio_in (data-TRANSIENT): 16 bytes
mod_deflate unzip the content properly, but as the request leaves the proxy
toward the remote web server, the content remains unzipped, while header still
contains
the tag: Content-Encoding: gzip\r\n.
This results in data inconsistency - thus remote server refuses to accept the
request.
the same occurs back in response:
Zipped Content arriving in response from remote web server, is inflated in
proxy, but then when response is going toward client (after proxy)
the content is not zipped, while header still exists.
Resulting client application receiving errors.
I had to create a w/a for this issue, in order to overcome the bug:
In PRSFixup, I'm removing the "content-encoding", and "accept-encoding" tags.
So that it will not be sent to remote server, but, I have to add back the
"content-encoding" tag in aprHook, in order for mod_deflate to inflate the
content, so that our proprietary filter will be able to work properly.
But, as a result, network traffic is enlarged dramatically.
To summarize,
This bug contains two different bugs:
1. mod_deflate promises to remove the "content-encoding : gzip" from HTTP
header, but upon inflating content, somehow apache proxy leaves the tag in
outgoing request.
2. mod_deflate doesn't contain appropriate filter to zip back outgoing request
content when apache is working in reverse proxy mode.
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[Bug 53160] Reverse Proxy mod_deflate doesn't zip back content in
outgoing traffic
Posted by bu...@apache.org.
https://issues.apache.org/bugzilla/show_bug.cgi?id=53160
Adi Levy <al...@salesforce.com> changed:
What |Removed |Added
----------------------------------------------------------------------------
Priority|P2 |P1
CC| |alevy@salesforce.com
--- Comment #1 from Adi Levy <al...@salesforce.com> ---
Logs will be added according to request.
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[Bug 53160] Reverse Proxy mod_deflate doesn't zip back content in
outgoing traffic
Posted by bu...@apache.org.
https://issues.apache.org/bugzilla/show_bug.cgi?id=53160
ybudweiser <yb...@gmail.com> changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |ybudweiser@gmail.com
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[Bug 53160] Reverse Proxy mod_deflate doesn't zip back content in
outgoing traffic
Posted by bu...@apache.org.
https://issues.apache.org/bugzilla/show_bug.cgi?id=53160
Adi Levy <al...@salesforce.com> changed:
What |Removed |Added
----------------------------------------------------------------------------
Severity|normal |critical
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[Bug 53160] Reverse Proxy mod_deflate doesn't zip back content in
outgoing traffic
Posted by bu...@apache.org.
https://issues.apache.org/bugzilla/show_bug.cgi?id=53160
FN <li...@felix-nawroth.net> changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |lists@felix-nawroth.net
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[Bug 53160] Reverse Proxy mod_deflate doesn't zip back content in
outgoing traffic
Posted by bu...@apache.org.
https://issues.apache.org/bugzilla/show_bug.cgi?id=53160
--- Comment #2 from FN <li...@felix-nawroth.net> ---
I can confirm the left-in Content-encoding header, which breaks a proxy chain
in which every proxy is configured with InputFilter Deflate, for versions
2.2.18 to 2.2.22.
To fix mod_deflate not recompressing outgoing requests please try
SetOutputFilter INFLATE;DEFLATE
or
SetOutputFilter INFLATE;proxy-html;DEFLATE
(according to http://www.apachetutor.org/apps/reverseproxies and/or
http://www.apachetutor.org/admin/reverseproxies)
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