889775 - png image can't be read on wordpress

Status: VERIFIED WONTFIX

(Core :: Graphics: ImageLib, defect)

Description

[Ripato]

User Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.6; rv:22.0) Gecko/20100101 Firefox/22.0 (Beta/Release)
Build ID: 20130618035212

Steps to reproduce:

I made a wordpress website contained png glitched images. I download firefox 22.0


Actual results:

After the upgrade, png images can't be read

Comment 1

[Loic]

Attachment: robe.png

Comment 2

[Loic]

If I open the attached PNG directly from BMO, the image appears briefly then Firefox displays a message saying there are some errors in the image.

Regression range:
good=2013-03-21
bad=2013-03-22
http://hg.mozilla.org/mozilla-central/pushloghtml?fromchange=1d6fe70c79c5&tochange=0e9badd3cf39

Suspected bug: Bug 716140 - Multithreaded image decoding

Comment 3

[Alex Keybl [:akeybl]]

Joe - this is only a single instance of a corrupt issue. Any reason to believe this will impact a significant portion of PNGs? Holding off on tracking until we hear back.

Comment 4

[Joe Drew (not getting mail)]

We know that we made several instances of corrupted PNGs not decode any more; we worked around some of this with bug 857040, but there are more instances out there. This shouldn't be too terribly bad in general, though.

Comment 5

[Glenn Randers-Pehrson]

This one is corrupted enough that pngcrush and pngcheck can't read it.  Chrome displays it but it's obviously corrupted.  Nightly flashes the image and displays the error msg

Comment 6

[Glenn Randers-Pehrson]

To let mozilla display this corrupted image we'd need to defeat the libpng CRC checking (easy to do) and also zlib's Adler32 checksum checking (also possible).  I don't think that's the right thing to do, however.

Comment 7

[Joe Drew (not getting mail)]

I don't think we should try to make this image display. For now, we won't try to fix it.

Comment 8

[Glenn Randers-Pehrson]

Agreed.  I have spent some time trying to ignore the zlib error but just got into more libpng errors or core dumps.  I think "fixing" this bug would just lead to a larger territory for security researchers and bounty hunters to explore.