netdev - Re: [PATCH net 1/2] net: introduce device min_header

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Date:   Tue, 07 Feb 2017 13:20:18 -0800
From:   Eric Dumazet <eric.dumazet@...il.com>
To:     Willem de Bruijn <willemdebruijn.kernel@...il.com>
Cc:     netdev@...r.kernel.org, davem@...emloft.net,
        sowmini.varadhan@...cle.com, dvyukov@...gle.com,
        Willem de Bruijn <willemb@...gle.com>
Subject: Re: [PATCH net 1/2] net: introduce device min_header_len

On Tue, 2017-02-07 at 15:57 -0500, Willem de Bruijn wrote:
> From: Willem de Bruijn <willemb@...gle.com>
> 
> The stack must not pass packets to device drivers that are shorter
> than the minimum link layer header length.
> 
> Previously, packet sockets would drop packets smaller than or equal
> to dev->hard_header_len, but this has false positives. Zero length
> payload is used over Ethernet. Other link layer protocols support
> variable length headers. Support for validation of these protocols
> removed the min length check for all protocols.
> 
> Introduce an explicit dev->min_header_len parameter and drop all
> packets below this value. Initially, set it to non-zero only for
> Ethernet and loopback. Other protocols can follow in a patch to
> net-next.
> 
> Fixes: 9ed988cd5915 ("packet: validate variable length ll headers")
> Reported-by: Sowmini Varadhan <sowmini.varadhan@...cle.com>
> Signed-off-by: Willem de Bruijn <willemb@...gle.com>
> ---

Acked-by: Eric Dumazet <edumazet@...gle.com>