From 8a0859b65b06ea07461271ce4f1fe25b48d1ec55 Mon Sep 17 00:00:00 2001 From: "Du, Changbin" Date: Fri, 18 Dec 2015 15:36:40 +0800 Subject: [PATCH] usb: gadget: forbid queuing request to a disabled ep Queue a request to disabled ep doesn't make sense, and induce caller make mistakes. Here is a example for the android mtp gadget function driver. A mem corruption can happen on below senario. 1) On disconnect, mtp driver disable its EPs, 2) During send_file_work and receive_file_work, mtp queues a request to ep. (The mtp driver need improve its synchronization logic!) 3) mtp_function_unbind is invoked and all mtp requests are freed. 4) when udc process the request queued on step 2, will cause kernel NULL pointer dereference exception. Signed-off-by: Du, Changbin Signed-off-by: Felipe Balbi --- include/linux/usb/gadget.h | 3 +++ 1 file changed, 3 insertions(+) diff --git a/include/linux/usb/gadget.h b/include/linux/usb/gadget.h index 92467eea76de..d82d0068872b 100644 --- a/include/linux/usb/gadget.h +++ b/include/linux/usb/gadget.h @@ -402,6 +402,9 @@ static inline void usb_ep_free_request(struct usb_ep *ep, static inline int usb_ep_queue(struct usb_ep *ep, struct usb_request *req, gfp_t gfp_flags) { + if (WARN_ON_ONCE(!ep->enabled && ep->address)) + return -ESHUTDOWN; + return ep->ops->queue(ep, req, gfp_flags); } -- 2.20.1