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From: "Gao Feng" <gfree.wind@foxmail.com>
To: "'Pablo Neira Ayuso'" <pablo@netfilter.org>, <fgao@ikuai8.com>
Cc: <davem@davemloft.net>, <jolsa@redhat.com>,
	<netfilter-devel@vger.kernel.org>, <netdev@vger.kernel.org>,
	<gfree.wind@gmail.com>
Subject: RE: [PATCH nf v3 1/1] netfilter: snmp: Fix one possible panic when snmp_trap_helper fail to register
Date: Fri, 24 Mar 2017 20:42:07 +0800	[thread overview]
Message-ID: <000401d2a49c$0d094350$271bc9f0$@foxmail.com> (raw)
In-Reply-To: <20170324122301.GA3160@salvia>

Hi Pablo,

> -----Original Message-----
> From: netfilter-devel-owner@vger.kernel.org
> [mailto:netfilter-devel-owner@vger.kernel.org] On Behalf Of Pablo Neira
Ayuso
> Sent: Friday, March 24, 2017 8:23 PM
> To: fgao@ikuai8.com
> Cc: davem@davemloft.net; jolsa@redhat.com;
netfilter-devel@vger.kernel.org;
> netdev@vger.kernel.org; gfree.wind@gmail.com
> Subject: Re: [PATCH nf v3 1/1] netfilter: snmp: Fix one possible panic
when
> snmp_trap_helper fail to register
> 
> On Fri, Mar 24, 2017 at 01:21:30PM +0100, Pablo Neira Ayuso wrote:
> > On Tue, Mar 21, 2017 at 08:22:29AM +0800, fgao@ikuai8.com wrote:
> > > From: Gao Feng <fgao@ikuai8.com>
> > >
> > > In the commit 93557f53e1fb ("netfilter: nf_conntrack: nf_conntrack
> > > snmp helper"), the snmp_helper is replaced by nf_nat_snmp_hook. So
> > > the snmp_helper is never registered. But it still tries to
> > > unregister the snmp_helper, it could cause the panic.
> >
> > This patch looks correct to me.
> >
> > But probably for some reason I don't manage to trigger, how do you
> > reproduce this?
> 
> I'm refering to the panic.
[高峰] 
It is got by reviewing the codes.
When nf_conntrack_helper_unregister(&snmp_helper), but snmp_helper didn't
register actually.
And snmp_helper. hnode is not initialized, it would trigger the issue when
hlist_del_rcu in nf_conntrack_helper_unregister.

Best Regards
Feng


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  reply	other threads:[~2017-03-24 12:50 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-03-21  0:22 [PATCH nf v3 1/1] netfilter: snmp: Fix one possible panic when snmp_trap_helper fail to register fgao
2017-03-24 12:21 ` Pablo Neira Ayuso
2017-03-24 12:23   ` Pablo Neira Ayuso
2017-03-24 12:42     ` Gao Feng [this message]
2017-03-24 19:01 ` Pablo Neira Ayuso
2017-03-25  2:10   ` Gao Feng

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