drivers/gpu/drm/i915/i915_gem.c in the Graphics Execution Manager (GEM) in the Intel i915 driver in the Direct Rendering Manager (DRM) subsystem in the Linux kernel before 2.6.36 does not properly validate pointers to blocks of memory, which allows local users to write to arbitrary kernel memory locations, and consequently gain privileges, via crafted use of the ioctl interface, related to (1) pwrite and (2) pread operations.