Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit bab9efc2 authored by Xi Wang's avatar Xi Wang Committed by Dave Airlie
Browse files

vmwgfx: integer overflow in vmw_kms_update_layout_ioctl() 



There are two issues in vmw_kms_update_layout_ioctl().  First, the
for loop forgets to index rects and only checks the first element.
Second, there is a potential integer overflow if userspace passes
in a large arg->num_outputs.  The call to kzalloc() would allocate
a small buffer, leading to out-of-bounds read.

Reported-by: default avatarHaogang Chen <haogangchen@gmail.com>
Signed-off-by: default avatarXi Wang <xi.wang@gmail.com>
Signed-off-by: default avatarThomas Hellstrom <thellstrom@vmware.com>
Signed-off-by: default avatarDave Airlie <airlied@redhat.com>
parent f3a71df0

drivers/gpu/drm/vmwgfx/vmwgfx_kms.c

+6 −5
Original line number Diff line number Diff line
@@ -1809,7 +1809,8 @@ int vmw_kms_update_layout_ioctl(struct drm_device *dev, void *data, 
	}



	rects_size = arg->num_outputs * sizeof(struct drm_vmw_rect);

	rects = kzalloc(rects_size, GFP_KERNEL);

	rects = kcalloc(arg->num_outputs, sizeof(struct drm_vmw_rect),

			GFP_KERNEL);

	if (unlikely(!rects)) {

		ret = -ENOMEM;

		goto out_unlock;
@@ -1824,10 +1825,10 @@ int vmw_kms_update_layout_ioctl(struct drm_device *dev, void *data, 
	}



	for (i = 0; i < arg->num_outputs; ++i) {

		if (rects->x < 0 ||

		    rects->y < 0 ||

		    rects->x + rects->w > mode_config->max_width ||

		    rects->y + rects->h > mode_config->max_height) {

		if (rects[i].x < 0 ||

		    rects[i].y < 0 ||

		    rects[i].x + rects[i].w > mode_config->max_width ||

		    rects[i].y + rects[i].h > mode_config->max_height) {

			DRM_ERROR("Invalid GUI layout.\n");

			ret = -EINVAL;

			goto out_free;