Integer signedness error in the drm_modeset_ctl function in (1) drivers/gpu/drm/drm_irq.c...

Vulnerability Description

Integer signedness error in the drm_modeset_ctl function in (1) drivers/gpu/drm/drm_irq.c in the Direct Rendering Manager (DRM) subsystem in the Linux kernel before 2.6.38 and (2) sys/dev/pci/drm/drm_irq.c in the kernel in OpenBSD before 4.9 allows local users to trigger out-of-bounds write operations, and consequently cause a denial of service (system crash) or possibly have unspecified other impact, via a crafted num_crtcs (aka vb_num) structure member in an ioctl argument.

References

• https://exchange.xforce.ibmcloud.com/vulnerabilities/67199
• http://www.securityfocus.com/bid/47639
• https://bugzilla.redhat.com/show_bug.cgi?id=679925
• http://www.openbsd.org/cgi-bin/cvsweb/src/sys/dev/pci/drm/drm_irq.c.diff?r1=1.41%3Br2=1.42%3Bf=h
• http://www.openbsd.org/cgi-bin/cvsweb/src/sys/dev/pci/drm/drm_irq.c
• http://www.kernel.org/pub/linux/kernel/v2.6/ChangeLog-2.6.38
• http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git%3Ba=commit%3Bh=1922756124ddd53846877416d92ba4a802bc658f