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From: Eric Dumazet <eric.dumazet@gmail.com>
To: Florian Westphal <fw@strlen.de>
Cc: Dmitry Vyukov <dvyukov@google.com>,
	syzkaller <syzkaller@googlegroups.com>,
	Hannes Frederic Sowa <hannes@stressinduktion.org>,
	David Miller <davem@davemloft.net>,
	Tom Herbert <tom@herbertland.com>,
	Alexander Duyck <aduyck@mirantis.com>,
	Jiri Benc <jbenc@redhat.com>,
	Sabrina Dubroca <sd@queasysnail.net>,
	netdev <netdev@vger.kernel.org>,
	LKML <linux-kernel@vger.kernel.org>
Subject: Re: net: GPF in eth_header
Date: Mon, 28 Nov 2016 14:14:04 -0800	[thread overview]
Message-ID: <1480371244.18162.91.camel@edumazet-glaptop3.roam.corp.google.com> (raw)
In-Reply-To: <20161128213444.GA9858@breakpoint.cc>

On Mon, 2016-11-28 at 22:34 +0100, Florian Westphal wrote:
> Eric Dumazet <eric.dumazet@gmail.com> wrote:
> > > Might be a bug added in commit daaa7d647f81f3
> > > ("netfilter: ipv6: avoid nf_iterate recursion")
> > > 
> > > Florian, what do you think of dropping a packet that presumably was
> > > mangled badly by nf_ct_frag6_queue() ?
> 
> ipv4 definitely frees malformed packets.
> In general, I think netfilter should avoid 'silent' drops if possible
> and let skb continue, but of course such skbs should not be made worse
> as what we ate to begin with...
> 
> > > (Like about 48 byte pulled :(, and/or skb->csum changed )
> 
> I think this warrants a review of ipv6 reassembly too, bug reported here
> is because ipv6 nf defrag is also done on output.


ip6_frag_queue() definitely frees bad/mangled skbs()


> Looks good, we'll need to change some of the errno return codes in
> nf_ct_frag6_gather to 0 though for this to work, which should not be too
> hard ;)

If the goal is to let buggy packets pass, then we might need to undo
changes in nf_ct_frag6_queue()

  reply	other threads:[~2016-11-28 22:15 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-11-26 17:30 net: GPF in eth_header Dmitry Vyukov
2016-11-26 18:28 ` Eric Dumazet
2016-11-26 19:07   ` Andrey Konovalov
2016-11-26 20:05     ` Eric Dumazet
2016-11-26 20:34       ` Eric Dumazet
2016-11-29 10:26       ` Andrey Konovalov
2016-11-29 14:58         ` Eric Dumazet
2016-11-29 15:31           ` Andrey Konovalov
2016-11-29 16:15             ` Eric Dumazet
2016-11-28 18:50     ` Eric Dumazet
2016-11-28 19:04       ` Andrey Konovalov
2016-11-28 19:34         ` Dmitry Vyukov
2016-11-28 19:47           ` Eric Dumazet
2016-11-28 21:05             ` Eric Dumazet
2016-11-28 21:18               ` Eric Dumazet
2016-11-28 21:34                 ` Florian Westphal
2016-11-28 22:14                   ` Eric Dumazet [this message]
2016-11-28 22:19                     ` Florian Westphal
2016-11-28 23:16                       ` Eric Dumazet

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