staging: most: usb: check number of reported endpoints

This patch checks the number of endpoints reported by the USB
interface descriptor and throws an error if the number exceeds
MAX_NUM_ENDPOINTS.
Signed-off-by: Christian Gromm <christian.gromm@microchip.com>
Reported-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Link: https://lore.kernel.org/r/1589534465-7423-4-git-send-email-christian.gromm@microchip.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/most/usb/usb.c

@@ -950,13 +950,17 @@ hdm_probe(struct usb_interface *interface, const struct usb_device_id *id)
 	unsigned int num_endpoints;
 	struct most_channel_capability *tmp_cap;
 	struct usb_endpoint_descriptor *ep_desc;
-	int ret = 0;
+	int ret = -ENOMEM;
 
 	if (!mdev)
-		goto err_out_of_memory;
+		return -ENOMEM;
 
 	usb_set_intfdata(interface, mdev);
 	num_endpoints = usb_iface_desc->desc.bNumEndpoints;
+	if (num_endpoints > MAX_NUM_ENDPOINTS) {
+		kfree(mdev);
+		return -EINVAL;
+	}
 	mutex_init(&mdev->io_mutex);
 	INIT_WORK(&mdev->poll_work_obj, wq_netinfo);
 	timer_setup(&mdev->link_stat_timer, link_stat_timer_handler, 0);
@@ -1085,11 +1089,6 @@ hdm_probe(struct usb_interface *interface, const struct usb_device_id *id)
 	kfree(mdev->conf);
 err_free_mdev:
 	put_device(&mdev->dev);
-err_out_of_memory:
-	if (ret == 0 || ret == -ENOMEM) {
-		ret = -ENOMEM;
-		dev_err(dev, "out of memory\n");
-	}
 	return ret;
 }