Subject: Re: [PATCH v1 net] packet: handle too big packets for PACKET_V3

From: Daniel Borkmann <[email-masked]>
Date: Mon, 18 Aug 2014 17:39:02 +0200

On 08/15/2014 06:16 PM, Eric Dumazet wrote:
> From: Eric Dumazet <[email-masked]>
>
> af_packet can currently overwrite kernel memory by out of bound
> accesses, because it assumed a [new] block can always hold one frame.
>
> This is not generally the case, even if most existing tools do it right.
>
> This patch clamps too long frames as API permits, and issue a one time
> error on syslog.
>
> [  394.357639] tpacket_rcv: packet too big, clamped from 5042 to 3966. macoff=82
>
> In this example, packet header tp_snaplen was set to 3966,
> and tp_len was set to 5042 (skb->len)
>
> Signed-off-by: Eric Dumazet <[email-masked]>
> Fixes: f6fb8f100b80 ("af-packet: TPACKET_V3 flexible buffer implementation.")

Acked-by: Daniel Borkmann <[email-masked]>

This looks good to me, thanks Eric!

[ Truly dislike the TPACKET_V3 code ... :/ ]