From: David Miller <davem@davemloft.net>
To: phil@nwl.cc
Cc: netdev@vger.kernel.org, johann.baudy@gnu-log.net, eric.dumazet@gmail.com
Subject: Re: sending VLAN packets via packet_mmap
Date: Wed, 06 Oct 2010 23:53:43 -0700 (PDT) [thread overview]
Message-ID: <20101006.235343.98903661.davem@davemloft.net> (raw)
In-Reply-To: <20100930192414.GD26509@orbit.nwl.cc>
From: Phil Sutter <phil@nwl.cc>
Date: Thu, 30 Sep 2010 21:24:14 +0200
> The actual problem in tpacket_snd() is this:
>
> | reserve = dev->hard_header_len;
> | [...]
> | if (size_max > dev->mtu + reserve)
> | size_max = dev->mtu + reserve;
>
> I guess the check is there to avoid skb overflows on malicious data
> input. Is this correct? Are there other reasons for it's existence?
We can add a special allowance of 4 extra bytes in this size check
_iff_ the device is ethernet and the NETIF_F_VLAN_CHALLENGED netdev
feature bit is not set.
next prev parent reply other threads:[~2010-10-07 6:53 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-09-30 19:24 sending VLAN packets via packet_mmap Phil Sutter
2010-10-07 6:53 ` David Miller [this message]
2010-10-11 13:15 ` Phil Sutter
2010-10-11 13:25 ` [PATCH] af_packet: account for VLAN when checking packet size Phil Sutter
2010-10-11 14:03 ` Eric Dumazet
2010-10-11 16:01 ` David Miller
2010-10-11 17:29 ` Phil Sutter
2010-10-12 17:19 ` Michael S. Tsirkin
2010-10-12 17:40 ` David Miller
2010-10-22 8:41 ` Simon Horman
2010-10-27 15:48 ` David Miller
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