hamradio: remove needs_free_netdev to avoid UAF
The former patch "defer 6pack kfree after unregister_netdev" reorders the kfree of two buffer after the unregister_netdev to prevent the race condition. It also adds free_netdev() function in sixpack_close(), which is a direct copy from the similar code in mkiss_close(). However, in sixpack driver, the flag needs_free_netdev is set to true in sp_setup(), hence the unregister_netdev() will free the netdev automatically. Therefore, as the sp is netdev_priv, use-after-free occurs. This patch removes the needs_free_netdev = true and just let the free_netdev to finish this deallocation task. Fixes: 0b911192 ("hamradio: defer 6pack kfree after unregister_netdev") Signed-off-by:Lin Ma <linma@zju.edu.cn> Link: https://lore.kernel.org/r/20211111141402.7551-1-linma@zju.edu.cn Signed-off-by:
Jakub Kicinski <kuba@kernel.org>
parent
66f4beaa