Last modified: 2012-08-23 19:33:57 UTC

Wikimedia Bugzilla is closed!

Wikimedia has migrated from Bugzilla to Phabricator. Bug reports should be created and updated in Wikimedia Phabricator instead. Please create an account in Phabricator and add your Bugzilla email address to it.
Wikimedia Bugzilla is read-only. If you try to edit or create any bug report in Bugzilla you will be shown an intentional error message.
In order to access the Phabricator task corresponding to a Bugzilla report, just remove "static-" from its URL.
You could still run searches in Bugzilla or access your list of votes but bug reports will obviously not be up-to-date in Bugzilla.
Bug 1248 - Perform fuller check for file corruption on image uploads
Perform fuller check for file corruption on image uploads
Status: RESOLVED INVALID
Product: MediaWiki
Classification: Unclassified
File management (Other open bugs)
1.3.x
All All
: Low enhancement (vote)
: ---
Assigned To: Nobody - You can work on this!
: testme
Depends on:
Blocks:
  Show dependency treegraph
 
Reported: 2005-01-02 02:01 UTC by peter green
Modified: 2012-08-23 19:33 UTC (History)
3 users (show)

See Also:
Web browser: ---
Mobile Platform: ---
Assignee Huggle Beta Tester: ---


Attachments

Description peter green 2005-01-02 02:01:33 UTC
i thought mediawiki was performing validations on uploaded images due to
scripting related issues with IE.

however
http://upload.wikimedia.org/wikipedia/commons/archive/d/df/20041231015421%21Warminsko-mazurskie_flaga.png
is definately broken (it wouldn't scale in wikipedia and it crashes paint shop
pro 4) how did the validator for png pass this?
Comment 1 Brion Vibber 2005-01-07 03:48:12 UTC
The file passes PHP's getimagesize() function and the 'file' command identifies it as:
20041231015421!Warminsko-mazurskie_flaga.png: PNG image data, 350 x 178, 8-bit/color RGB, interlaced

It likely is corrupted (Mac OS X's Preview.app refuses to load it as well) but it has an intact header, and gqview and Gimp are able to 
extract a complete image from it (presumably both using libpng), with an error message noting that there may be corruption:

Gimp: "Error while reading '/home/brion/20041231015421!Warminsko-mazurskie_flaga.png'. File corrupted?"
GQView "libpng error: Too many IDAT's found".

ClamAV does not detect it as a known "virus"-type image.

You should file a bug report with the makers of Paint Shop Pro that their software crashes on malformed input instead of failing 
gracefully.
Comment 2 peter green 2005-01-07 04:05:11 UTC
well the version of paint shop pro i use is extremely old (it does what i wan't
so im not splashing out to upgrade). so i can't really file a bug report with them.

also whilst i don't belive this particular file is malicious the better the
checking applied to uploads the less chance we will get bitten by an infected
image in future.
Comment 3 peter green 2005-01-07 22:13:19 UTC
i was writing a program to generate pngs and i ran into theese same symptoms psp
crashing imagemagick giving a (fairly useless) error and other things reading
them fine.

with my program i found the issue was caused by garbage after the end of the
compressed data inside the data chunk though i have no way to check if this is
the case for the image presented here.

imo its probablly worth attempting a rescale at upload time using imagemagick on
the grounds that we wan't to be able to rescale all images.
Comment 4 Nemo 2012-08-23 09:33:05 UTC
(In reply to comment #1)
> You should file a bug report with the makers of Paint Shop Pro that their
> software crashes on malformed input instead of failing 
> gracefully.

Invalid, upstream? Anyway this bug is too old and generic to be useful, MediaWiki does perform validation as far as I can see.
Comment 5 Bawolff (Brian Wolff) 2012-08-23 19:33:57 UTC
> Invalid, upstream? Anyway this bug is too old and generic to be useful,
> MediaWiki does perform validation as far as I can see.

Well both, we shouldn't accept invalid files by any stretch of the imagination. Some of our checks are better than others. Lots of our checks are superficial, but I think there is other bugs covering that.

Note You need to log in before you can comment on or make changes to this bug.


Navigation
Links