From mboxrd@z Thu Jan  1 00:00:00 1970
From: Eric Dumazet <eric.dumazet@gmail.com>
Subject: Re: [RFC] Kernel unaligned access at __skb_flow_dissect
Date: Fri, 29 Jan 2016 12:06:53 -0800
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Cc: David Miller <davem@davemloft.net>, netdev@vger.kernel.org
To: Sowmini Varadhan <sowmini.varadhan@oracle.com>
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On Fri, 2016-01-29 at 12:01 -0800, Eric Dumazet wrote:
> On Fri, 2016-01-29 at 14:44 -0500, Sowmini Varadhan wrote:
> > On (01/29/16 11:37), Eric Dumazet wrote:
> > > 
> > > I have no idea why reading iph->saddr or iph->daddr would not hit the
> > > problem, but accessing the 32bit ipv6 flow label would be an issue.
> > > 
> > > Something is fishy.
> > 
> > I was wondering about this myself. Even on sparc, I only first
> > ran into the errors for ipv6. I dont know if the fact that the
> > saddr is memcpy'ed masks the error (even though the problem
> > is still there). 
> 
> Oh right, recent work in flow dissector added all these memcpy()
> 
> I was still looking at linux-4.3 ;)

The code for GRE/GRE_KEY is still accessing 32bit vars.

const __be32 *keyid;
...
key_keyid->keyid = *keyid;

So instead of auditing flow dissect code, we should fix the few drivers
using it.