netdev - Re: [RFC] Kernel unaligned access at __skb_flow

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 linux-cve-announce 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]

Message-ID: <1454098013.7627.71.camel@edumazet-glaptop2.roam.corp.google.com>
Date:	Fri, 29 Jan 2016 12:06:53 -0800
From:	Eric Dumazet <eric.dumazet@...il.com>
To:	Sowmini Varadhan <sowmini.varadhan@...cle.com>
Cc:	David Miller <davem@...emloft.net>, netdev@...r.kernel.org
Subject: Re: [RFC] Kernel unaligned access at __skb_flow_dissect

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.