xhci: Fix use-after-free in xhci_free_virt_device

KASAN found a use-after-free in xhci_free_virt_device+0x33b/0x38e
where xhci_free_virt_device() sets slot id to 0 if udev exists:
if (dev->udev && dev->udev->slot_id)
	dev->udev->slot_id = 0;

dev->udev will be true even if udev is freed because dev->udev is
not set to NULL.

set dev->udev pointer to NULL in xhci_free_dev()

The original patch went to stable so this fix needs to be applied
there as well.

Fixes: a400efe455 ("xhci: zero usb device slot_id member when disabling and freeing a xhci slot")
Cc: <stable@vger.kernel.org>
Reported-by: Guenter Roeck <linux@roeck-us.net>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Tested-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Mathias Nyman 2018-05-03 17:30:07 +03:00 committed by Greg Kroah-Hartman
parent 9aea9b6cc7
commit 44a182b9d1

View File

@ -3621,6 +3621,7 @@ static void xhci_free_dev(struct usb_hcd *hcd, struct usb_device *udev)
del_timer_sync(&virt_dev->eps[i].stop_cmd_timer);
}
xhci_debugfs_remove_slot(xhci, udev->slot_id);
virt_dev->udev = NULL;
ret = xhci_disable_slot(xhci, udev->slot_id);
if (ret)
xhci_free_virt_device(xhci, udev->slot_id);