Bug 1269562 (CVE-2015-8896)

Summary: CVE-2015-8896 ImageMagick: Integer truncation vulnerability in coders/pict.c
Product: [Other] Security Response Reporter: Adam Mariš <amaris>
Component: vulnerabilityAssignee: Red Hat Product Security <security-response-team>
Status: CLOSED ERRATA QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: bleanhar, ccoleman, dmcphers, ethan, jhorak, jialiu, jkeck, jokerman, lmeyer, mmccomas, nmurray, pahan, sardella, slawomir, yozone
Target Milestone: ---Keywords: Security
Target Release: ---   
Hardware: All   
OS: Linux   
Whiteboard:
Fixed In Version: Doc Type: Bug Fix
Doc Text:
Story Points: ---
Clone Of: Environment:
Last Closed: 2019-06-08 02:43:53 UTC Type: ---
Regression: --- Mount Type: ---
Documentation: --- CRM:
Verified Versions: Category: ---
oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
Embargoed:
Bug Depends On: 1269567, 1341777, 1341778, 1341779, 1341780    
Bug Blocks: 1269566, 1333419    

Description Adam Mariš 2015-10-07 14:42:37 UTC 
An integer truncation flaw leading to a heap-based buffer overflow was found in ImageMagick in pict.c. 

Detailed stacktrace with reproducer can be found here:

https://bugs.launchpad.net/ubuntu/+source/imagemagick/+bug/1448803

Upstream patch for the pict.c problem is a subsection (the pict.c part) of the following commit:
https://github.com/ImageMagick/ImageMagick/commit/0f6fc2d5bf8f500820c3dbcf0d23ee14f2d9f734

CVE request:

http://seclists.org/oss-sec/2015/q4/45
Comment 1 Adam Mariš 2015-10-07 14:46:01 UTC 
Created ImageMagick tracking bugs for this issue:

Affects: fedora-all [bug 1269567]
Comment 2 Stefan Cornelius 2015-10-08 13:26:51 UTC 
Upstream patch for the pict.c problem is a subsection (the pict.c part) of the following commit:
https://github.com/ImageMagick/ImageMagick/commit/0f6fc2d5bf8f500820c3dbcf0d23ee14f2d9f734

When calculating the amount of bytes per row, the result is truncated down to unsigned short.
> row_bytes=(unsigned short) (image->columns | 0x8000);
or
> row_bytes=(unsigned short) ((4*image->columns) | 0x8000);


This truncated value is later used to allocate the scanline memory (if image->columns is big, the resulting row_bytes value may turn out to be too small):
> scanline=(unsigned char *) AcquireQuantumMemory(row_bytes,sizeof(*scanline));

Finally, we calculate pointers into the scanline buffer via:
>        red=scanline;
>        green=scanline+image->columns;
>        blue=scanline+2*image->columns;
>        opacity=scanline+3*image->columns;

Notice that when calculating e.g. "blue", the original, non-truncated image->columns value is taken, possibly leading to out-of-bounds writes when trying to write pixels into the scanline buffer.
Comment 7 Stefan Cornelius 2016-06-16 12:11:50 UTC 
The TGA flaw (CVE-2015-8894) has been moved to:
https://bugzilla.redhat.com/show_bug.cgi?id=1347275
Comment 8 errata-xmlrpc 2016-06-16 22:47:46 UTC 
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 6
  Red Hat Enterprise Linux 7

Via RHSA-2016:1237 https://access.redhat.com/errata/RHSA-2016:1237