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Posted to dev@httpd.apache.org by Marc Slemko <ma...@worldgate.com> on 1998/08/02 02:46:08 UTC
Re: [PATCH] mod_proxy, yet another netscape bug
On Sun, 2 Aug 1998, Lars Eilebrecht wrote:
> Hi,
>
> a friend of mine discovered a Navigator/Mozilla bug which
> results in broken images in some rare cases.
> (I was able to reproduce the bug under Solaris 2.6 with Netscape
> Communicator 4.05.)
>
> If you load a page that contains _direct_ links to images via mod_proxy
> and try to load the images you'll maybe receive a broken image (is does
> not happen with inline images).
>
> Dependent on the length of the http header and TCP/IP settings/values
> (MTU, path-MTU, segment size etc) the first read() of Netscape reads
> the header plus the beginning of the body. But it seems that Netscape
> expects to see only http headers in his first read(), because
> the beginning of the body gets ignored. Therefore Netscape fails to
> display the image. Shift-Reloading the image-URL works...
Are you sure this isn't just the same thing as the 25[678] byte Navigator
bug that we already work around, but perhaps showing up differently
because it is coming from the proxy?
/* Navigator versions 2.x, 3.x and 4.0 betas up to and including 4.0b2
* have a header parsing bug. If the terminating \r\n occur starting
* at offset 256, 257 or 258 of output then it will not properly parse
* the headers. Curiously it doesn't exhibit this problem at 512, 513.
* We are guessing that this is because their initial read of a new request
* uses a 256 byte buffer, and subsequent reads use a larger buffer.
* So the problem might exist at different offsets as well.
*
* This should also work on keepalive connections assuming they use the
* same small buffer for the first read of each new request.
*
* At any rate, we check the bytes written so far and, if we are about to
* tickle the bug, we instead insert a bogus padding header. Since the bug
* manifests as a broken image in Navigator, users blame the server. :(
* It is more expensive to check the User-Agent than it is to just add the
* bytes, so we haven't used the BrowserMatch feature here.
>
> The patch contains a workaround for this bug (added a call to
> ap_bflush() in proxy_http.c/proxy_ftp.c right before mod_proxy
I don't like that fix. It is the wrong way to do things.
Re: [PATCH] mod_proxy, yet another netscape bug
Posted by Marc Slemko <ma...@worldgate.com>.
Not that I am aware of. It would take someone who understands basic C
code to do that.
On Sun, 2 Aug 1998, Lars Eilebrecht wrote:
> According to Marc Slemko:
>
> > Are you sure this isn't just the same thing as the 25[678] byte Navigator
> > bug that we already work around, but perhaps showing up differently
> > because it is coming from the proxy?
>
> No I'm not sure, but wasn't this bug fixed in the current Navigator versions?
>
>
> ciao...
> --
> Lars Eilebrecht - Hackers do it with bugs.
> sfx@unix-ag.org
> http://www.home.unix-ag.org/sfx/
>
Re: [PATCH] mod_proxy, yet another netscape bug
Posted by Lars Eilebrecht <La...@unix-ag.org>.
According to Marc Slemko:
> Are you sure this isn't just the same thing as the 25[678] byte Navigator
> bug that we already work around, but perhaps showing up differently
> because it is coming from the proxy?
No I'm not sure, but wasn't this bug fixed in the current Navigator versions?
ciao...
--
Lars Eilebrecht - Hackers do it with bugs.
sfx@unix-ag.org
http://www.home.unix-ag.org/sfx/