===================================================================
@@ -1848,6 +1848,17 @@ static int hub_probe(struct usb_interfac
hdev = interface_to_usbdev(intf);
/*
+ * The USB 2.0 spec prohibits hubs from having more than one
+ * configuration or interface, and we rely on this prohibition.
+ * Refuse to accept a device that violates it.
+ */
+ if (hdev->descriptor.bNumConfigurations > 1 ||
+ hdev->actconfig->desc.bNumInterfaces > 1) {
+ dev_err(&intf->dev, "Invalid hub with more than one config or interface\n");
+ return -EINVAL;
+ }
+
+ /*
* Set default autosuspend delay as 0 to speedup bus suspend,
* based on the below considerations:
*
Robert Morris created a test program which can cause usb_hub_to_struct_hub() to dereference a NULL or inappropriate pointer: Oops: general protection fault, probably for non-canonical address 0xcccccccccccccccc: 0000 [#1] SMP DEBUG_PAGEALLOC PTI CPU: 7 UID: 0 PID: 117 Comm: kworker/7:1 Not tainted 6.13.0-rc3-00017-gf44d154d6e3d #14 Hardware name: FreeBSD BHYVE/BHYVE, BIOS 14.0 10/17/2021 Workqueue: usb_hub_wq hub_event RIP: 0010:usb_hub_adjust_deviceremovable+0x78/0x110 ... Call Trace: <TASK> ? die_addr+0x31/0x80 ? exc_general_protection+0x1b4/0x3c0 ? asm_exc_general_protection+0x26/0x30 ? usb_hub_adjust_deviceremovable+0x78/0x110 hub_probe+0x7c7/0xab0 usb_probe_interface+0x14b/0x350 really_probe+0xd0/0x2d0 ? __pfx___device_attach_driver+0x10/0x10 __driver_probe_device+0x6e/0x110 driver_probe_device+0x1a/0x90 __device_attach_driver+0x7e/0xc0 bus_for_each_drv+0x7f/0xd0 __device_attach+0xaa/0x1a0 bus_probe_device+0x8b/0xa0 device_add+0x62e/0x810 usb_set_configuration+0x65d/0x990 usb_generic_driver_probe+0x4b/0x70 usb_probe_device+0x36/0xd0 The cause of this error is that the device has two interfaces, and the hub driver binds to interface 1 instead of interface 0, which is where usb_hub_to_struct_hub() looks. We can prevent the problem from occurring by refusing to accept hub devices that violate the USB spec by having more than one configuration or interface. Reported-and-tested-by: Robert Morris <rtm@csail.mit.edu> Closes: https://lore.kernel.org/linux-usb/95564.1737394039@localhost/ Signed-off-by: Alan Stern <stern@rowland.harvard.edu> --- drivers/usb/core/hub.c | 11 +++++++++++ 1 file changed, 11 insertions(+)