netdev - Re: [RFC] packet: handle too big packets for PACKET

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Thu, 14 Aug 2014 19:01:25 -0700
From:	Eric Dumazet <eric.dumazet@...il.com>
To:	Hannes Frederic Sowa <hannes@...essinduktion.org>
Cc:	Daniel Borkmann <dborkman@...hat.com>,
	Neil Horman <nhorman@...driver.com>,
	Jesper Dangaard Brouer <brouer@...hat.com>,
	David Miller <davem@...emloft.net>,
	netdev <netdev@...r.kernel.org>
Subject: Re: [RFC] packet: handle too big packets for PACKET_V3

On Fri, 2014-08-15 at 03:04 +0200, Hannes Frederic Sowa wrote:

> Sure, but if I would have written such a tool without knowledge of GRO I
> would have queried at least the MTU. ;)

Would all existing tools react to a mtu change properly ?

(It would have to reinit its af_packet ring)

I do not think its a GRO issue, really, but an optimistic PACKET_V3
implementation. GRO was already there when PACKET_V3 was added.

Even a non GRO packet might not fit and we need to avoid the
crash/corruption.

I believe I am going to implement 2)  (clamp the snaplen)

An application should catch that tp_len might be bigger than tp_snaplen
and eventually do something sensible about it.

BTW, tp_sizeof_priv doesnt look to be checked at all, user input is
accepted as is.

--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html