Package: chromium Version: 18.0.1025.151~r130497-1 Severity: normal Tags: upstream
When saving a file served with gzip Content-Encoding and application/x-gzip Content-Type, the file is saved compressed (Chromium does not decompress the content). Amazingly, all major browsers have the same problem. Firefox has it (see https://bugzilla.mozilla.org/show_bug.cgi?id=610679 ), Konqueror 4.7.4, Opera 11.62, Safari 5.1.4 and Internet Explorer 8. Even wget has the problem, in a sense (see http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=150766 ). The only browser which doesn't have this problem that I found is NetSurf (tested on version 2.8). Otherwise, curl doesn't have the problem.
I discovered this bug on http://release.debian.org/britney/ with update_output.txt.gz. The same problem also affects update_excuses.html.gz. The server is Apache. I was able to reproduce this using my system as the server and a random .txt.gz found locally (a README). The file I use to test is /usr/share/doc/xz-utils/faq.txt.gz from xz-utils and has MD5 sum 3d9b4fbacb5c1c4b6fc6930ad02abd28. When I download it and hit this bug, the double-gzipped version I get has MD5 sum 4b978d76df448f894fcf427f86d74674. I hit this bug when downloading from my local httpd, Apache 2.2.22 on testing, with a highly stock configuration.
In practice, this only happens when a gzipped file is gzipped during transfer, and this is understandably rare. It's a performance bug that Apache gzips a gzipped file, but it happens in a few situations, as in the case of a gzipped text file. Apache's content coding is managed by mod_deflate. mod_deflate is enabled by default, but only for some MIME types for which compression is known to be efficient, for example text files. The AddOutputFilterByType directive is used to tell mod_deflate to compress some MIME types. The default configuration (deflate.conf) contains:
AddOutputFilterByType DEFLATE text/html text/plain text/xml
It is arguably an Apache bug that problematic files (.txt.gz) are considered as text/plain, since they're compressed, but this is what happens, and explains the server's behavior.
The problem does not only happen with Apache, it also happened when I tried with lighttpd, but not by default. By default, lighttpd would send Content-Type application/octet-stream IIRC. After some hacking in lighttpd.conf (compress.filetype = ( "application/javascript", "text/css", "text/html", "text/plain", "application/x-gzip" )) and /usr/share/lighttpd/create-mime.assign.pl, I obtained the same problem. I added the following just before the last line of /usr/share/lighttpd/create-mime.assign.pl:
print ' ".tar.gz" => "application/x-tgz",'; print "\n"; print ' ".gz" => "application/x-gzip",'; print "\n";
This was reported upstream in http://code.google.com/p/chromium/issues/detail?id=47951 but this will not be fixed upstream.
faq.txt.gz
Description: application/gzip
