drm/i915: fix integer overflow in i915_gem_execbuffer2()
authorXi Wang <xi.wang@gmail.com>
Mon, 23 Apr 2012 08:06:41 +0000 (04:06 -0400)
committerDaniel Vetter <daniel.vetter@ffwll.ch>
Mon, 23 Apr 2012 20:32:02 +0000 (22:32 +0200)
On 32-bit systems, a large args->buffer_count from userspace via ioctl
may overflow the allocation size, leading to out-of-bounds access.

This vulnerability was introduced in commit 8408c282 ("drm/i915:
First try a normal large kmalloc for the temporary exec buffers").

Signed-off-by: Xi Wang <xi.wang@gmail.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: stable@vger.kernel.org
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
drivers/gpu/drm/i915/i915_gem_execbuffer.c

index f51a696486cb19f06822f84a10f4a6911c1bd7d8..7c50e58175c027c6326081243ca3533f477fa612 100644 (file)
@@ -1404,7 +1404,8 @@ i915_gem_execbuffer2(struct drm_device *dev, void *data,
        struct drm_i915_gem_exec_object2 *exec2_list = NULL;
        int ret;
 
-       if (args->buffer_count < 1) {
+       if (args->buffer_count < 1 ||
+           args->buffer_count > UINT_MAX / sizeof(*exec2_list)) {
                DRM_DEBUG("execbuf2 with %d buffers\n", args->buffer_count);
                return -EINVAL;
        }