[PATCH 4.9 33/60] USB: hub: fix SS max number of ports

Greg Kroah-Hartman
2017-06-19T15:29:35Z

From: Johan Hovold <johan@kernel.org>

commit 93491ced3c87c94b12220dbac0527e1356702179 upstream.

Add define for the maximum number of ports on a SuperSpeed hub as per
USB 3.1 spec Table 10-5, and use it when verifying the retrieved hub
descriptor.

This specifically avoids benign attempts to update the DeviceRemovable
mask for non-existing ports (should we get that far).

Fixes: dbe79bbe9dcb ("USB 3.0 Hub Changes")
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>

---
drivers/usb/core/hub.c | 8 +++++++-
include/uapi/linux/usb/ch11.h | 3 +++
2 files changed, 10 insertions(+), 1 deletion(-)

--- a/drivers/usb/core/hub.c
+++ b/drivers/usb/core/hub.c
@@ -1334,7 +1334,13 @@ static int hub_configure(struct usb_hub
if (ret < 0) {
message = "can't read hub descriptor";
goto fail;
- } else if (hub->descriptor->bNbrPorts > USB_MAXCHILDREN) {
+ }
+
+ maxchild = USB_MAXCHILDREN;
+ if (hub_is_superspeed(hdev))
+ maxchild = min_t(unsigned, maxchild, USB_SS_MAXPORTS);
+
+ if (hub->descriptor->bNbrPorts > maxchild) {
message = "hub has too many ports!";
ret = -ENODEV;
goto fail;
--- a/include/uapi/linux/usb/ch11.h
+++ b/include/uapi/linux/usb/ch11.h
@@ -22,6 +22,9 @@
*/
#define USB_MAXCHILDREN 31

+/* See USB 3.1 spec Table 10-5 */
+#define USB_SS_MAXPORTS 15
+
/*
* Hub request types
*/