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.
Alan Stern
> 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;
> }
> @@ -1321,7 +1325,7 @@ static int hub_configure(struct usb_hub *hub,
>
> /* Request the entire hub descriptor.
> * hub->descriptor can handle USB_MAXCHILDREN ports,
> - * but the hub can/will return fewer bytes here.
> + * but a (non-SS) hub can/will return fewer bytes here.
> */
> ret = get_hub_descriptor(hdev, hub->descriptor);
> if (ret < 0) {
>