Bug 1378760 – CVE-2016-7528 ImageMagick: out of bound access for viff file coder

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Bug 1378760 - (CVE-2016-7528) CVE-2016-7528 ImageMagick: out of bound access for viff file coder

Summary:	CVE-2016-7528 ImageMagick: out of bound access for viff file coder

Status:	CLOSED WONTFIX

Aliases:	CVE-2016-7528

Product:	Security Response
Classification:	Other
Component:	vulnerability (Show other bugs)
Sub Component:
Version:	unspecified
Hardware:	All Linux

Priority	medium Severity medium
Target Milestone:	---
Target Release:	---
Assigned To:	Red Hat Product Security
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URL:
Whiteboard:	impact=moderate,public=20160124,repor...
Keywords:	Security

Depends On:	1378790
Blocks:	1378785
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Reported:	2016-09-23 04:52 EDT by Adam Mariš
Modified:	2017-05-19 05:09 EDT (History)
CC List:	13 users (show)

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Last Closed:	2017-05-19 05:09:21 EDT
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Description Adam Mariš 2016-09-23 04:52:48 EDT

Bug report(s):

https://github.com/ImageMagick/ImageMagick/issues/99
https://bugs.launchpad.net/bugs/1537425

Upstream patch(es):

https://github.com/ImageMagick/ImageMagick/commit/ca0c886abd6d3ef335eb74150cd23b89ebd17135

CVE assignment:

http://seclists.org/oss-sec/2016/q3/590

Comment 1 Adam Mariš 2016-09-23 05:35:19 EDT

Created ImageMagick tracking bugs for this issue:

Affects: fedora-all [bug 1378790]

Comment 2 Stefan Cornelius 2016-09-29 06:45:48 EDT

coders/viff.c:
> number_pixels=(MagickSizeType) image->columns*image->rows;
> for (y=0; y < (ssize_t) image->rows; y++)
> {
>   q=QueueAuthenticPixels(image,0,y,image->columns,1,exception);
>   if (q == (PixelPacket *) NULL)
>    break;
>   for (x=0; x < (ssize_t) image->columns; x++)
>   {
>       SetPixelRed(q,ScaleCharToQuantum(*p));
>       SetPixelGreen(q,ScaleCharToQuantum(*(p+number_pixels)));
>       SetPixelBlue(q,ScaleCharToQuantum(*(p+2*number_pixels)));
>       if (image->colors != 0)

Depending on the image dimensions, number_pixels can be quite large
> number_pixels=(MagickSizeType) image->columns*image->rows;

This causes problems when adding this to "p" to calculate the address. It could wrap around and cause an access to invalid memory.
>       SetPixelGreen(q,ScaleCharToQuantum(*(p+number_pixels)));
>       SetPixelBlue(q,ScaleCharToQuantum(*(p+2*number_pixels)));

I'm not sure if the upstream patch properly protects against that.

Comment 3 Stefan Cornelius 2017-05-19 05:09:38 EDT

Statement:

Red Hat Product Security has rated this issue as having Moderate security impact. This issue is not currently planned to be addressed in future updates. For additional information, refer to the Issue Severity Classification: https://access.redhat.com/security/updates/classification/.

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