Re: [PATCH] drm/nouveau/core/object: Fix the uninitialized use of "type"

[Lyude Paul]

Reviewed-by: Lyude Paul <lyude@xxxxxxxxxx>

On Fri, 2021-12-17 at 18:56 -0800, Yizhuo Zhai wrote:
> In function nvkm_ioctl_map(), the variable "type" could be
> uninitialized if "nvkm_object_map()" returns error code, however,
> it does not check the return value and directly use the "type" in
> the if statement, which is potentially unsafe.
> 
> Cc: stable@xxxxxxxxxxxxxxx
> Fixes: 01326050391c ("drm/nouveau/core/object: allow arguments to be passed
> to map function")
> Signed-off-by: Yizhuo Zhai <yzhai003@xxxxxxx>
> ---
>  drivers/gpu/drm/nouveau/nvkm/core/ioctl.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/drivers/gpu/drm/nouveau/nvkm/core/ioctl.c
> b/drivers/gpu/drm/nouveau/nvkm/core/ioctl.c
> index 735cb6816f10..4264d9d79783 100644
> --- a/drivers/gpu/drm/nouveau/nvkm/core/ioctl.c
> +++ b/drivers/gpu/drm/nouveau/nvkm/core/ioctl.c
> @@ -266,6 +266,8 @@ nvkm_ioctl_map(struct nvkm_client *client,
>                 ret = nvkm_object_map(object, data, size, &type,
>                                       &args->v0.handle,
>                                       &args->v0.length);
> +               if (ret)
> +                       return ret;
>                 if (type == NVKM_OBJECT_MAP_IO)
>                         args->v0.type = NVIF_IOCTL_MAP_V0_IO;
>                 else

-- 
Cheers,
 Lyude Paul (she/her)
 Software Engineer at Red Hat