From 5b24c28cfe136597dc3913e1c00b119307a20c7e Mon Sep 17 00:00:00 2001 From: Bryan O'Donoghue Date: Thu, 9 Jan 2020 13:17:21 +0000 Subject: usb: gadget: f_ncm: Use atomic_t to track in-flight request Currently ncm->notify_req is used to flag when a request is in-flight. ncm->notify_req is set to NULL and when a request completes it is subsequently reset. This is fundamentally buggy in that the unbind logic of the NCM driver will unconditionally free ncm->notify_req leading to a NULL pointer dereference. Fixes: 40d133d7f542 ("usb: gadget: f_ncm: convert to new function interface with backward compatibility") Cc: stable Signed-off-by: Bryan O'Donoghue Signed-off-by: Felipe Balbi Signed-off-by: Greg Kroah-Hartman --- drivers/usb/gadget/function/f_ncm.c | 17 +++++++++++++---- 1 file changed, 13 insertions(+), 4 deletions(-) (limited to 'drivers/usb/gadget/function/f_ncm.c') diff --git a/drivers/usb/gadget/function/f_ncm.c b/drivers/usb/gadget/function/f_ncm.c index 2d6e76e4cffa..1d900081b1f0 100644 --- a/drivers/usb/gadget/function/f_ncm.c +++ b/drivers/usb/gadget/function/f_ncm.c @@ -53,6 +53,7 @@ struct f_ncm { struct usb_ep *notify; struct usb_request *notify_req; u8 notify_state; + atomic_t notify_count; bool is_open; const struct ndp_parser_opts *parser_opts; @@ -547,7 +548,7 @@ static void ncm_do_notify(struct f_ncm *ncm) int status; /* notification already in flight? */ - if (!req) + if (atomic_read(&ncm->notify_count)) return; event = req->buf; @@ -587,7 +588,8 @@ static void ncm_do_notify(struct f_ncm *ncm) event->bmRequestType = 0xA1; event->wIndex = cpu_to_le16(ncm->ctrl_id); - ncm->notify_req = NULL; + atomic_inc(&ncm->notify_count); + /* * In double buffering if there is a space in FIFO, * completion callback can be called right after the call, @@ -597,7 +599,7 @@ static void ncm_do_notify(struct f_ncm *ncm) status = usb_ep_queue(ncm->notify, req, GFP_ATOMIC); spin_lock(&ncm->lock); if (status < 0) { - ncm->notify_req = req; + atomic_dec(&ncm->notify_count); DBG(cdev, "notify --> %d\n", status); } } @@ -632,17 +634,19 @@ static void ncm_notify_complete(struct usb_ep *ep, struct usb_request *req) case 0: VDBG(cdev, "Notification %02x sent\n", event->bNotificationType); + atomic_dec(&ncm->notify_count); break; case -ECONNRESET: case -ESHUTDOWN: + atomic_set(&ncm->notify_count, 0); ncm->notify_state = NCM_NOTIFY_NONE; break; default: DBG(cdev, "event %02x --> %d\n", event->bNotificationType, req->status); + atomic_dec(&ncm->notify_count); break; } - ncm->notify_req = req; ncm_do_notify(ncm); spin_unlock(&ncm->lock); } @@ -1649,6 +1653,11 @@ static void ncm_unbind(struct usb_configuration *c, struct usb_function *f) ncm_string_defs[0].id = 0; usb_free_all_descriptors(f); + if (atomic_read(&ncm->notify_count)) { + usb_ep_dequeue(ncm->notify, ncm->notify_req); + atomic_set(&ncm->notify_count, 0); + } + kfree(ncm->notify_req->buf); usb_ep_free_request(ncm->notify, ncm->notify_req); } -- cgit v1.2.3-59-g8ed1b