On Wed, 10 May 2017, Johan Hovold wrote:
> On Wed, May 10, 2017 at 10:04:32AM -0400, Alan Stern wrote:
> > On Wed, 10 May 2017, Johan Hovold wrote:
> >
> > > A SuperSpeed hub descriptor does not have any variable-length fields so
> > > bail out when reading a short descriptor.
> >
> > You mean: bail out when reading a descriptor that is not exactly the
> > right length. The existing code already bails out when it reads a
> > short descriptor.
>
> No, the current code happily accepts a 9-byte descriptor, while an SS
> descriptor is always 12 bytes. And since we request 12 bytes for SS
> hubs, the patch description is correct.
My mistake; you are right.
Acked-by: Alan Stern <stern@xxxxxxxxxxxxxxxxxxx>
>
> > > This avoids parsing and leaking two bytes of uninitialised slab data
> > > through sysfs removable-attributes.
> > >
> > > Fixes: dbe79bbe9dcb ("USB 3.0 Hub Changes")
> > > Cc: stable <stable@xxxxxxxxxxxxxxx> # 2.6.39
> > > Cc: John Youn <John.Youn@xxxxxxxxxxxx>
> > > Signed-off-by: Johan Hovold <johan@xxxxxxxxxx>
> > > ---
> > > drivers/usb/core/hub.c | 8 ++++++--
> > > 1 file changed, 6 insertions(+), 2 deletions(-)
> > >
> > > diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
> > > index 9dca59ef18b3..3ff1e9f89f2d 100644
> > > --- a/drivers/usb/core/hub.c
> > > +++ b/drivers/usb/core/hub.c
> > > @@ -380,8 +380,12 @@ static int get_hub_descriptor(struct usb_device *hdev, void *data)
> > > USB_REQ_GET_DESCRIPTOR, USB_DIR_IN | USB_RT_HUB,
> > > dtype << 8, 0, data, size,
> > > USB_CTRL_GET_TIMEOUT);
> > > - if (ret >= (USB_DT_HUB_NONVAR_SIZE + 2))
> > > + if (hub_is_superspeed(hdev)) {
> > > + if (ret == size)
> > > + return ret;
> > > + } else if (ret >= (USB_DT_HUB_NONVAR_SIZE + 2)) {
> > > return ret;
> > > + }
> > > }
> > > return -EINVAL;
> > > }
>
> Thanks,
> Johan
>
>