[patch 4/4 v2] drm/qxl: integer overflow in qxl_alloc_surf_ioctl()
Frediano Ziglio
fziglio at redhat.com
Wed Sep 23 03:45:05 PDT 2015
>
> The size calculation can overflow. I don't know if this leads to
> memory corruption, but it causes a static checker warning.
>
> Signed-off-by: Dan Carpenter <dan.carpenter at oracle.com>
> ---
> v2: I don't know think the size is capped anywhere. In my first version
> of this patch, I introduced a divide by zero bug.
>
Beside the second sentence I would ack
Frediano
> diff --git a/drivers/gpu/drm/qxl/qxl_ioctl.c
> b/drivers/gpu/drm/qxl/qxl_ioctl.c
> index b2db482..49b3158 100644
> --- a/drivers/gpu/drm/qxl/qxl_ioctl.c
> +++ b/drivers/gpu/drm/qxl/qxl_ioctl.c
> @@ -396,12 +396,14 @@ static int qxl_alloc_surf_ioctl(struct drm_device *dev,
> void *data,
> struct qxl_bo *qobj;
> int handle;
> int ret;
> - int size, actual_stride;
> + u64 size, actual_stride;
> struct qxl_surface surf;
>
> /* work out size allocate bo with handle */
> actual_stride = param->stride < 0 ? -param->stride : param->stride;
> size = actual_stride * param->height + actual_stride;
> + if (size > INT_MAX)
> + return -EINVAL;
>
> surf.format = param->format;
> surf.width = param->width;
>
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