netdev - Re: Deadlock with icmpv6fuzz

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Date:	Fri, 6 Feb 2009 20:22:18 +1100
From:	Herbert Xu <herbert@...dor.apana.org.au>
To:	David Miller <davem@...emloft.net>
Cc:	rdreier@...co.com, snakebyte@....de, netdev@...r.kernel.org,
	yoshfuji@...ux-ipv6.org
Subject: Re: Deadlock with icmpv6fuzz

On Fri, Feb 06, 2009 at 01:05:59AM -0800, David Miller wrote:
> From: Herbert Xu <herbert@...dor.apana.org.au>
> Date: Fri, 6 Feb 2009 19:54:06 +1100
> 
> > This should eliminate the backtrace as reported, but it'll just
> > show up somewhere else.  In particular, the control message (see
> > sys_sendmsg) itself is copied to kernel memory via kmalloc and
> > it's limited to INT_MAX :)
> 
> Can you be more specific, do you mean this is happening
> via datagram_send_ctl()?

Well the data that led to the back trace came from a cmsg, I was
merely pointing out that the cmsg itself is kmalloced and copied
by sys_sendmsg and it's only limited to INT_MAX.

So even if you throw away the message in IPv6, sys_sendmsg will
still do an even bigger allocation on that message which is just
as likely to fail.

Cheers,
-- 
Visit Openswan at http://www.openswan.org/
Email: Herbert Xu ~{PmV>HI~} <herbert@...dor.apana.org.au>
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