diff --git a/drivers/usb/gadget/udc/core.c b/drivers/usb/gadget/udc/core.c index 60340ff9edbf..f6da12b553a0 100644 --- a/drivers/usb/gadget/udc/core.c +++ b/drivers/usb/gadget/udc/core.c @@ -31,8 +31,9 @@ static const struct bus_type gadget_bus_type; /** * struct usb_udc - describes one usb device controller * @driver: the gadget driver pointer. For use by the class code - * @dev: the child device to the actual controller * @gadget: the gadget. For use by the class code + * @gadget_release: the gadget's release routine + * @dev: the child device to the actual controller * @list: for use by the udc class driver * @vbus: for udcs who care about vbus status, this value is real vbus status; * for udcs who do not care about vbus status, this value is always true @@ -53,6 +54,7 @@ static const struct bus_type gadget_bus_type; struct usb_udc { struct usb_gadget_driver *driver; struct usb_gadget *gadget; + void (*gadget_release)(struct device *dev); struct device dev; struct list_head list; bool vbus; @@ -1362,6 +1364,17 @@ static void usb_udc_nop_release(struct device *dev) dev_vdbg(dev, "%s\n", __func__); } +static void usb_gadget_release(struct device *dev) +{ + struct usb_gadget *gadget = dev_to_usb_gadget(dev); + struct usb_udc *udc = gadget->udc; + /* Cache the gadget's release routine to prevent UAF */ + void (*release)(struct device *dev) = udc->gadget_release; + + put_device(&udc->dev); + release(dev); +} + /** * usb_initialize_gadget - initialize a gadget and its embedded struct device * @parent: the parent device to this udc. Usually the controller driver's @@ -1418,6 +1431,14 @@ int usb_add_gadget(struct usb_gadget *gadget) mutex_init(&udc->connect_lock); udc->started = false; + /* + * Align decoupled lifecycles: take a UDC reference to ensure it + * remains allocated until the gadget is released, requiring an + * override of the gadget's release routine to drop it. + */ + udc->gadget_release = gadget->dev.release; + gadget->dev.release = usb_gadget_release; + get_device(&udc->dev); mutex_lock(&udc_lock); list_add_tail(&udc->list, &udc_list); @@ -1462,6 +1483,12 @@ int usb_add_gadget(struct usb_gadget *gadget) mutex_lock(&udc_lock); list_del(&udc->list); mutex_unlock(&udc_lock); + /* + * Revert the override and drop the UDC reference to prevent + * leaking the UDC if the gadget was statically allocated. + */ + gadget->dev.release = udc->gadget_release; + put_device(&udc->dev); err_put_udc: put_device(&udc->dev);