In the Linux kernel, the following vulnerability has been resolved:
net: usb: kaweth: remove TX queue manipulation in kaweth_set_rx_mode
kaweth_set_rx_mode(), the ndo_set_rx_mode callback, calls netif_stop_queue() and netif_wake_queue(). These are TX queue flow control functions unrelated to RX multicast configuration.
The premature netif_wake_queue() can re-enable TX while tx_urb is still in-flight, leading to a double usb_submit_urb() on the same URB:
kaweth_start_xmit() { netif_stop_queue(); usb_submit_urb(kaweth->tx_urb); }
kaweth_set_rx_mode() { netif_stop_queue(); netif_wake_queue(); // wakes TX queue before URB is done }
kaweth_start_xmit() { netif_stop_queue(); usb_submit_urb(kaweth->tx_urb); // URB submitted while active }
This triggers the WARN in usb_submit_urb():
"URB submitted while active"
This is a similar class of bug fixed in rtl8150 by
- commit 958baf5eaee3 ("net: usb: Remove disruptive netif_wake_queue in rtl8150_set_multicast").
Also kaweth_set_rx_mode() is already functionally broken, the real set_rx_mode action is performed by kaweth_async_set_rx_mode(), which in turn is not a no-op only at ndo_open() time.