Red Hat Bugzilla – Bug 1325090
CVE-2016-3624 libtiff: out of bounds write in the rgb2ycybr tool
Last modified: 2017-05-11 06:18:24 EDT
Out of bounds write vulnerability was found in cvtClump function in rgb2ycybr.c, allowing attacker to cause a denial of service via a crafted TIFF image. Vulnerable code: libtiff-master/libtiff/rgb2ycbcr.c:193 187 lumaGreen[TIFFGetG(RGB)] + 188 lumaBlue[TIFFGetB(RGB)]; 189 /* accumulate chrominance */ 190 Cb += (TIFFGetB(RGB) - Y) * D1; 191 Cr += (TIFFGetR(RGB) - Y) * D2; 192 /* emit luminence */ 193 *op++ = V2Code(Y, 194 refBlackWhite[0], refBlackWhite[1], 255); 195 } Public via: http://seclists.org/oss-sec/2016/q2/28
Acknowledgments: Name: Mei Wang (Qihoo 360)
The command line parameters passed to the tool influence the calculations within the cvtRaster() function in gb2ycbcr.c. This can lead to a call to _TIFFmalloc() with a bogus size. If this allocation fails, NULL is returned. The application doesn't check for this condition, which ultimately leads to an access violation when the cvtClump() function tries to write "into" it. I've not really investigated what happens if the allocation succeeds - worst case could be a memory corruption, but since this issue depends on far-fetched custom command line parameters, I consider the likelyhood and impact of this to be minimal.
External References: http://bugzilla.maptools.org/show_bug.cgi?id=2568
Statement: Red Hat Product Security has rated this issue as having Low 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/.