netdev - Re: [PATCH net] net: mangle zero checksum in skb_checksum

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Message-Id: <20161031.152932.840383254132956388.davem@davemloft.net>
Date:   Mon, 31 Oct 2016 15:29:32 -0400 (EDT)
From:   David Miller <davem@...emloft.net>
To:     eric.dumazet@...il.com
Cc:     netdev@...r.kernel.org, maze@...gle.com, willemb@...gle.com
Subject: Re: [PATCH net] net: mangle zero checksum in skb_checksum_help()

From: Eric Dumazet <eric.dumazet@...il.com>
Date: Sat, 29 Oct 2016 11:02:36 -0700

> From: Eric Dumazet <edumazet@...gle.com>
> 
> Sending zero checksum is ok for TCP, but not for UDP.
> 
> UDPv6 receiver should by default drop a frame with a 0 checksum,
> and UDPv4 would not verify the checksum and might accept a corrupted
> packet.
> 
> Simply replace such checksum by 0xffff, regardless of transport.
> 
> This error was caught on SIT tunnels, but seems generic.
> 
> Signed-off-by: Eric Dumazet <edumazet@...gle.com>

Applied and queued up for -stable, thanks.