Assure that the control endpoint buffer of size USB_BUFSIZ (4096) can not be overflown during handling of USB control transfer requests with wLength greater than USB_BUFSIZ.
Signed-off-by: Szymon Heidrich szymon.heidrich@gmail.com --- drivers/usb/gadget/composite.c | 11 +++++++++++ 1 file changed, 11 insertions(+)
diff --git a/drivers/usb/gadget/composite.c b/drivers/usb/gadget/composite.c index 2a309e624e..cb89f6dca9 100644 --- a/drivers/usb/gadget/composite.c +++ b/drivers/usb/gadget/composite.c @@ -1019,6 +1019,17 @@ composite_setup(struct usb_gadget *gadget, const struct usb_ctrlrequest *ctrl) u8 endp; struct usb_configuration *c;
+ if (w_length > USB_BUFSIZ) { + if (ctrl->bRequestType & USB_DIR_IN) { + /* Cast away the const, we are going to overwrite on purpose. */ + __le16 *temp = (__le16 *)&ctrl->wLength; + *temp = cpu_to_le16(USB_BUFSIZ); + w_length = USB_BUFSIZ; + } else { + goto done; + } + } + /* * partial re-init of the response message; the function or the * gadget might need to intercept e.g. a control-OUT completion