From: Willem de Bruijn <willemdebruijn.ker...@gmail.com>
Date: Thu, 10 Aug 2017 12:29:19 -0400
> From: Willem de Bruijn <will...@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 <andreyk...@google.com>
> Signed-off-by: Willem de Bruijn <will...@google.com>
Applied and queued up for -stable.
