RE: UDP data corruption in v4.4

From: Greg KH greg@kroah.com Sent: Friday, July 24, 2020 10:59 PM

...

[...] Eric Dumazet made an alternative that performs the csum validation earlier:

--- a/net/ipv4/udp.c +++ b/net/ipv4/udp.c @@ -1589,8 +1589,7 @@ int udp_queue_rcv_skb(struct sock *sk, struct sk_buff *skb) } }

•   if (rcu_access_pointer(sk->sk_filter) &&
  

•       udp_lib_checksum_complete(skb))
  

•   if (udp_lib_checksum_complete(skb))
            goto csum_error;
  
    if (sk_rcvqueues_full(sk, sk->sk_rcvbuf)) {
  
  

I personally like Eric's fix and IMHO we'd better have it in v4.4 rather than trying to backport 327868212381.

Does Eric's fix work with your testing?

Yes, it worked in my testing overnight.

If so, great, can you turn it into something I can apply to the 4.4.y stable tree and send it to stable@vger.kernel.org?

greg k-h

Will do shortly.

Thanks, Dexuan