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From: Martin KaFai Lau <kafai@fb.com>
To: Phil Sutter <phil@nwl.cc>
Cc: <netdev@vger.kernel.org>,
	Hannes Frederic Sowa <hannes@stressinduktion.org>,
	Steffen Klassert <steffen.klassert@secunet.com>,
	Julian Anastasov <ja@ssi.bg>
Subject: Re: NULL pointer dereference in rt6_get_cookie()
Date: Mon, 12 Oct 2015 13:31:16 -0700	[thread overview]
Message-ID: <20151012203116.GC88112@canlin-mbp1.DHCP.thefacebook.com> (raw)
In-Reply-To: <20151010132437.GB25926@orbit.nwl.cc>

On Sat, Oct 10, 2015 at 03:24:37PM +0200, Phil Sutter wrote:
> Using printk-debugging I could track down the problem to
> rt6_get_cookie() function in include/net/ip6_fib.h:
>
> The conditional at the start of the function evaluates true, since
> 'rt->rt6i_flags & RTF_PCPU' is non-zero. Due to that, 'rt' pointer is
> reassigned:
>
> | rt = (struct rt6_info *)(rt->dst.from);
>
> It appears that this effectively assigns NULL to it, and the following
> dereference causes the bug.
Thanks for the report.  I am looking into it.

--Martin

  reply	other threads:[~2015-10-12 20:31 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-10-10 13:24 NULL pointer dereference in rt6_get_cookie() Phil Sutter
2015-10-12 20:31 ` Martin KaFai Lau [this message]
2015-10-13 18:14 ` Martin KaFai Lau
2015-10-13 19:10   ` Phil Sutter
2015-10-13 19:30     ` Martin KaFai Lau
     [not found]   ` <20151013191039.GA3070@base.sg13b.nwl.cc>
2015-10-13 19:26     ` Phil Sutter
2015-10-14  6:14       ` Martin KaFai Lau
2015-10-14 22:34         ` Phil Sutter
2015-10-14 23:17           ` Martin KaFai Lau

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