From: Antonio Quartulli <antonio@meshcoding•com>
To: David Miller <davem@davemloft•net>
Cc: netdev@vger•kernel.org
Subject: Re: [PATCH net] netpoll: linearize skb before accessing its data
Date: Tue, 22 Oct 2013 08:06:35 +0200 [thread overview]
Message-ID: <20131022060635.GF1544@neomailbox.net> (raw)
In-Reply-To: <20131021.182319.625146263287554088.davem@davemloft.net>
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On Mon, Oct 21, 2013 at 06:23:19PM -0400, David Miller wrote:
> From: Antonio Quartulli <antonio@meshcoding•com>
> Date: Mon, 21 Oct 2013 23:31:20 +0200
>
> > __netpoll_rx() assumes that the data buffer of the received
> > skb is linear and then passes it to rx_hook().
> > However this is not true because the skb has not been
> > linearized yet.
> >
> > This can cause rx_hook() to access non allocated memory
> > while parsing the received data.
> >
> > Fix __netpoll_rx() by explicitly linearising the skb.
> >
> > Signed-off-by: Antonio Quartulli <antonio@meshcoding•com>
>
> It is rx_hook's obligation to access the SKB properly and not
> assume that the SKB is linear. It is very expensive to
> linearize every SKB just for the sake of improperly implemented
> receive hooks.
>
> In particular the rx hooks must make use of interface such
> as pskb_may_pull(), just like every other protocol does
> on packet input processing, to make sure the area they want
> to access is in the linear area.
>
But rx_hook() does not receive any skb:
609 np->rx_hook(np, ntohs(uh->source),
610 (char *)(uh+1),
611 ulen - sizeof(struct udphdr));
it just receives a pointer to the data and can't do anything to make it linear.
(uh is a pointer to the udp header). Am I missing something?
Regards,
--
Antonio Quartulli
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next prev parent reply other threads:[~2013-10-22 6:07 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-10-21 21:31 [PATCH net] netpoll: linearize skb before accessing its data Antonio Quartulli
2013-10-21 22:23 ` David Miller
2013-10-22 6:06 ` Antonio Quartulli [this message]
2013-10-22 6:25 ` David Miller
2013-10-22 6:37 ` Antonio Quartulli
2013-10-22 6:50 ` David Miller
2013-10-22 8:48 ` [PATCH net] netpoll: fix rx_hook() interface by passing the skb Antonio Quartulli
2013-10-22 9:09 ` David Laight
2013-10-22 10:11 ` Antonio Quartulli
2013-10-22 12:46 ` David Laight
2013-10-22 17:13 ` Antonio Quartulli
2013-10-22 19:40 ` David Miller
2013-10-23 8:33 ` David Laight
2013-10-23 10:28 ` Antonio Quartulli
2013-10-23 11:18 ` David Laight
2013-10-23 12:44 ` Antonio Quartulli
2013-10-23 20:16 ` David Miller
2013-10-23 21:36 ` [PATCHv2 " Antonio Quartulli
2013-10-24 8:43 ` David Laight
2013-10-24 12:01 ` Antonio Quartulli
2013-10-24 17:53 ` David Miller
2013-10-25 23:27 ` David Miller
2013-10-21 22:25 ` [PATCH net] netpoll: linearize skb before accessing its data Eric Dumazet
2013-10-21 22:33 ` David Miller
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