usb: hub: add check for unsupported bus topology
We can't allow hubs on the 7th tier as they would allow
devices on the 8th tier.
Signed-off-by: Felipe Balbi <felipe.balbi@nokia.com>
Cc: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
diff --git a/drivers/usb/core/devices.c b/drivers/usb/core/devices.c
index a681d9b..6ec3817 100644
--- a/drivers/usb/core/devices.c
+++ b/drivers/usb/core/devices.c
@@ -61,8 +61,6 @@
#include "usb.h"
#include "hcd.h"
-#define MAX_TOPO_LEVEL 6
-
/* Define ALLOW_SERIAL_NUMBER if you want to see the serial number of devices */
#define ALLOW_SERIAL_NUMBER
diff --git a/drivers/usb/core/hcd.h b/drivers/usb/core/hcd.h
index 50b8bb2..5b0b59b 100644
--- a/drivers/usb/core/hcd.h
+++ b/drivers/usb/core/hcd.h
@@ -21,6 +21,8 @@
#include <linux/rwsem.h>
+#define MAX_TOPO_LEVEL 6
+
/* This file contains declarations of usbcore internals that are mostly
* used or exposed by Host Controller Drivers.
*/
diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
index e678ed8..3251120 100644
--- a/drivers/usb/core/hub.c
+++ b/drivers/usb/core/hub.c
@@ -1051,6 +1051,12 @@
desc = intf->cur_altsetting;
hdev = interface_to_usbdev(intf);
+ if (hdev->level == MAX_TOPO_LEVEL) {
+ dev_err(&intf->dev, "Unsupported bus topology: "
+ "hub nested too deep\n");
+ return -E2BIG;
+ }
+
#ifdef CONFIG_USB_OTG_BLACKLIST_HUB
if (hdev->parent) {
dev_warn(&intf->dev, "ignoring external hub\n");
