[PATCH] drm/amdgpu: fix integer overflow test in amdgpu_bo_list_create()

[Bas Nieuwenhuizen]

Reviewed-by: Bas Nieuwenhuizen <basni at chromium.org>
On Fri, Aug 10, 2018 at 12:50 PM Dan Carpenter <dan.carpenter at oracle.com> wrote:
>
> We accidentally left out the size of the amdgpu_bo_list struct.  It
> could lead to memory corruption on 32 bit systems.  You'd have to
> pick the absolute maximum and set "num_entries == 59652323" then size
> would wrap to 16 bytes.
>
> Fixes: 920990cb080a ("drm/amdgpu: allocate the bo_list array after the list")
> Signed-off-by: Dan Carpenter <dan.carpenter at oracle.com>
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_bo_list.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_bo_list.c
> index d472a2c8399f..b80243d3972e 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_bo_list.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_bo_list.c
> @@ -67,7 +67,8 @@ int amdgpu_bo_list_create(struct amdgpu_device *adev, struct drm_file *filp,
>         unsigned i;
>         int r;
>
> -       if (num_entries > SIZE_MAX / sizeof(struct amdgpu_bo_list_entry))
> +       if (num_entries > (SIZE_MAX - sizeof(struct amdgpu_bo_list))
> +                               / sizeof(struct amdgpu_bo_list_entry))
>                 return -EINVAL;
>
>         size = sizeof(struct amdgpu_bo_list);