Re: [PATCH net] udp: consistently apply ufo or fragmentation
flat view
From: David Miller <davem@davemloft.net>
Date: 2017-08-10 16:52:27
From: Willem de Bruijn <willemdebruijn.kernel@gmail.com> Date: Thu, 10 Aug 2017 12:29:19 -0400
From: Willem de Bruijn <willemb@google.com>
When iteratively building a UDP datagram with MSG_MORE and that
datagram exceeds MTU, consistently choose UFO or fragmentation.
Once skb_is_gso, always apply ufo. Conversely, once a datagram is
split across multiple skbs, do not consider ufo.
Sendpage already maintains the first invariant, only add the second.
IPv6 does not have a sendpage implementation to modify.
A gso skb must have a partial checksum, do not follow sk_no_check_tx
in udp_send_skb.
Found by syzkaller.
Fixes: e89e9cf539a2 ("[IPv4/IPv6]: UFO Scatter-gather approach")
Reported-by: Andrey Konovalov <redacted>
Signed-off-by: Willem de Bruijn <willemb@google.com>Applied and queued up for -stable.