1245975 - Confirmation code images (PNG) can not be loaded, "Image corrupt or truncated." message shown

Status: RESOLVED INCOMPLETE

(Core :: Graphics: ImageLib, defect, P3)

Description

[YF (Yang)]

STR:
Open the https://potplayer.daum.net/forum/ucp.php?mode=register, click the "I agree to these terms" button, and see the "Confirmation code". Or, open the https://potplayer.daum.net/forum/ucp.php?mode=confirm to see the images.


Actual results:
No shown. "Image corrupt or truncated." shown on Web Console.
The images works fine in IE 11, Chrome 48 and some viewer.

Comment 1

[Glenn Randers-Pehrson]

Enabled libpng warnings and saw this on the console window: [ImgDecoder #2]: E/PNGDecoder libpng error: Decompression error in IDAT

Not a lot more useful than the generic "image is corrupt" but does tell you that it's a damaged PNG file that is triggering the error.

Comment 2

[YF (Yang)]

In addition, no error message is displayed in the view, i.e. the "The image \u201c%S\u201d cannot be displayed because it contains errors.".

Comment 3

[Timothy Nikkel (:tnikkel)]

zlib fails here

https://dxr.mozilla.org/mozilla-central/source/modules/zlib/src/inflate.c#1189

hold is actually equal to state->check, but state->flags is zero, so ZSWAP32(hold)) has to be equal to state->check and it isn't. state->flags seems to come from the header, so it seems the header is set wrong.

Comment 4

[Glenn Randers-Pehrson]

Attachment: ucp.png (CAPTCHA image with bad zlib data)

Here's a CAPTCHA image from the site in question.  pngcrush-1.8.0 built with libpng-1.6.22 also rejects the image with "IDAT: incorrect data check", and ImageMagick built with libpng-1.6.20 rejects it with "Corrupt image".

pngcheck -v ucp.png says
File: ucp.png (16118 bytes)
  chunk IHDR at offset 0x0000c, length 13
    320 x 50 image, 8-bit grayscale, non-interlaced
  chunk IDAT at offset 0x00025, length 16061
    zlib: deflated, 32K window, superfast compression
  chunk IEND at offset 0x03eee, length 0

Comment 5

[Dennis Schubert [:denschub]]

The forum linked in this report no longer exists.