From: Pablo Neira Ayuso <pablo@netfilter•org>
To: Dave Jones <davej@redhat•com>
Cc: David Miller <davem@davemloft•net>,
netdev@vger•kernel.org,
Netfilter Development Mailinglist
<netfilter-devel@vger•kernel.org>
Subject: Re: [PATCH] Use unsigned variables for packet lengths in ip[6]_queue.
Date: Fri, 03 Jun 2011 12:07:37 +0200 [thread overview]
Message-ID: <4DE8B269.9070505@netfilter.org> (raw)
In-Reply-To: <20110528003651.GA8380@redhat.com>
On 28/05/11 02:36, Dave Jones wrote:
> On Tue, Apr 19, 2011 at 08:41:05PM -0700, David Miller wrote:
> > From: Dave Jones <davej@redhat•com>
> > Date: Tue, 19 Apr 2011 21:42:22 -0400
> >
> > > Not catastrophic, but ipqueue seems to be too trusting of what it gets
> > > passed from userspace, and passes it on down to the page allocator,
> > > where it will spew warnings if the page order is too high.
> > >
> > > __ipq_rcv_skb has several checks for lengths too small, but doesn't
> > > seem to have any for oversized ones. I'm not sure what the maximum
> > > we should check for is. I'll code up a diff if anyone has any ideas
> > > on a sane maximum.
> >
> > Maybe the thing to do is to simply pass __GFP_NOWARN to nlmsg_new()
> > in netlink_ack()?
> >
> > Anyone else have a better idea?
>
> So I went back to this today, and found something that doesn't look right.
> After adding some instrumentation, and re-running my tests, I found that
> the reason we were blowing up with enormous allocations was that we
> were passing down a nlmsglen's like -1061109568
>
> Is there any reason for that to be signed ?
> The nlmsg_len entry of nlmsghdr is a u32, so I'm assuming this is a bug.
>
> With the patch below, I haven't been able to reproduce the problem, but
> I don't know if I've inadvertantly broken some other behaviour somewhere
> deeper in netlink where this is valid.
I have applied this. Thanks.
BTW, ip[6]_queue has been marked obsoleted since long time, probably we
can schedule this for removal anytime soon. The nfnetlink_queue
successor has been there to provide a replacement for this since long time.
next prev parent reply other threads:[~2011-06-03 10:07 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-04-20 1:42 ipqueue allocation failure Dave Jones
2011-04-20 3:41 ` David Miller
2011-04-20 5:27 ` Eric Dumazet
2011-05-28 0:36 ` [PATCH] Use unsigned variables for packet lengths in ip[6]_queue Dave Jones
2011-06-02 19:24 ` Dave Jones
2011-06-02 20:57 ` David Miller
2011-06-07 12:59 ` Patrick McHardy
2011-06-07 14:19 ` Patrick McHardy
2011-06-07 14:39 ` Dave Jones
2011-06-07 15:19 ` Patrick McHardy
2011-06-03 10:07 ` Pablo Neira Ayuso [this message]
2011-04-21 15:13 ` ipqueue allocation failure Patrick McHardy
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