USB: hub: fix SS hub-descriptor handling

A SuperSpeed hub descriptor does not have any variable-length fields so
bail out when reading a short descriptor.

This avoids parsing and leaking two bytes of uninitialised slab data
through sysfs removable-attributes.

Fixes: e027f9002bec ("USB 3.0 Hub Changes")
Cc: stable <stable@vger.kernel.org>     # 2.6.39
Cc: John Youn <John.Youn@synopsys.com>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
index 9dca59ef18b3454437da9affb5e6d93619e88ba3..3ff1e9f89f2d54c71a5d864b78d657b275ecb2ac 100644 (file)
--- 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) {