usb: gadget: f_ecm: Use atomic_t to track in-flight request
commit5.4-rM2-2.2.x-imx-squashedd710562e01
upstream. Currently ecm->notify_req is used to flag when a request is in-flight. ecm->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 ECM driver will unconditionally free ecm->notify_req leading to a NULL pointer dereference. Fixes:da741b8c56
("usb ethernet gadget: split CDC Ethernet function") Cc: stable <stable@vger.kernel.org> Signed-off-by: Bryan O'Donoghue <bryan.odonoghue@linaro.org> Signed-off-by: Felipe Balbi <balbi@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
parent
a7d00597e0
commit
2068fbb20b
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@ -52,6 +52,7 @@ struct f_ecm {
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struct usb_ep *notify;
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struct usb_ep *notify;
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struct usb_request *notify_req;
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struct usb_request *notify_req;
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u8 notify_state;
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u8 notify_state;
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atomic_t notify_count;
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bool is_open;
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bool is_open;
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/* FIXME is_open needs some irq-ish locking
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/* FIXME is_open needs some irq-ish locking
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@ -380,7 +381,7 @@ static void ecm_do_notify(struct f_ecm *ecm)
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int status;
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int status;
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/* notification already in flight? */
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/* notification already in flight? */
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if (!req)
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if (atomic_read(&ecm->notify_count))
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return;
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return;
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event = req->buf;
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event = req->buf;
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@ -420,10 +421,10 @@ static void ecm_do_notify(struct f_ecm *ecm)
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event->bmRequestType = 0xA1;
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event->bmRequestType = 0xA1;
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event->wIndex = cpu_to_le16(ecm->ctrl_id);
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event->wIndex = cpu_to_le16(ecm->ctrl_id);
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ecm->notify_req = NULL;
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atomic_inc(&ecm->notify_count);
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status = usb_ep_queue(ecm->notify, req, GFP_ATOMIC);
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status = usb_ep_queue(ecm->notify, req, GFP_ATOMIC);
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if (status < 0) {
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if (status < 0) {
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ecm->notify_req = req;
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atomic_dec(&ecm->notify_count);
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DBG(cdev, "notify --> %d\n", status);
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DBG(cdev, "notify --> %d\n", status);
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}
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}
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}
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}
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@ -448,17 +449,19 @@ static void ecm_notify_complete(struct usb_ep *ep, struct usb_request *req)
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switch (req->status) {
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switch (req->status) {
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case 0:
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case 0:
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/* no fault */
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/* no fault */
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atomic_dec(&ecm->notify_count);
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break;
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break;
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case -ECONNRESET:
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case -ECONNRESET:
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case -ESHUTDOWN:
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case -ESHUTDOWN:
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atomic_set(&ecm->notify_count, 0);
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ecm->notify_state = ECM_NOTIFY_NONE;
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ecm->notify_state = ECM_NOTIFY_NONE;
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break;
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break;
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default:
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default:
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DBG(cdev, "event %02x --> %d\n",
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DBG(cdev, "event %02x --> %d\n",
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event->bNotificationType, req->status);
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event->bNotificationType, req->status);
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atomic_dec(&ecm->notify_count);
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break;
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break;
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}
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}
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ecm->notify_req = req;
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ecm_do_notify(ecm);
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ecm_do_notify(ecm);
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}
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}
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@ -907,6 +910,11 @@ static void ecm_unbind(struct usb_configuration *c, struct usb_function *f)
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usb_free_all_descriptors(f);
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usb_free_all_descriptors(f);
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if (atomic_read(&ecm->notify_count)) {
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usb_ep_dequeue(ecm->notify, ecm->notify_req);
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atomic_set(&ecm->notify_count, 0);
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}
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kfree(ecm->notify_req->buf);
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kfree(ecm->notify_req->buf);
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usb_ep_free_request(ecm->notify, ecm->notify_req);
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usb_ep_free_request(ecm->notify, ecm->notify_req);
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}
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}
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