Re: [PATCH] usb: musb: Fix potential NULL dereference

[Matwey V. Kornilov]

By the way, why do we need to store the qh in urb->hcpriv?
qh can always be accessible through urb->ep->hcpriv
Wouldn't it be better to drop entire urb->hcpriv usage?

ÑÑ, 23 ÑÐÐ. 2019 Ð. Ð 20:52, Matwey V. Kornilov <matwey@xxxxxxxxxx>:
>
> We assign "urb->hcpriv = qh;" a few lines down. The valid qh for the urb is
> hep->hcpriv in this code path.
>
> Fixes: 714bc5ef3eda ("musb: potential use after free")
> Signed-off-by: Matwey V. Kornilov <matwey@xxxxxxxxxx>
> ---
>  drivers/usb/musb/musb_host.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/usb/musb/musb_host.c b/drivers/usb/musb/musb_host.c
> index c6118a962d37..6f267716768e 100644
> --- a/drivers/usb/musb/musb_host.c
> +++ b/drivers/usb/musb/musb_host.c
> @@ -2336,7 +2336,7 @@ static int musb_urb_enqueue(
>                  * odd, rare, error prone, but legal.
>                  */
>                 kfree(qh);
> -               qh = NULL;
> +               qh = hep->hcpriv;
>                 ret = 0;
>         } else
>                 ret = musb_schedule(musb, qh,
> --
> 2.16.4
>


-- 
With best regards,
Matwey V. Kornilov