From: Florian Westphal <fw@strlen.de>
To: Pablo Neira Ayuso <pablo@netfilter.org>
Cc: Nikolay Aleksandrov <nikolay@cumulusnetworks.com>,
netdev@vger.kernel.org, Roopa Prabhu <roopa@cumulusnetworks.com>,
bridge@lists.linux-foundation.org, FlorianWestphal <fw@strlen.de>,
linux-kernel@vger.kernel.org,
Jozsef Kadlecsik <kadlec@netfilter.org>,
coreteam@netfilter.org, netfilter-devel@vger.kernel.org,
Leonardo Bras <leonardo@linux.ibm.com>,
"David S. Miller" <davem@davemloft.net>
Subject: Re: [Bridge] [PATCH v4 1/2] netfilter: Terminate rule eval if protocol=IPv6 and ipv6 module is disabled
Date: Tue, 3 Sep 2019 19:05:50 +0200 [thread overview]
Message-ID: <20190903170550.GA13660@breakpoint.cc> (raw)
In-Reply-To: <20190903164948.kuvtpy7viqhcmp77@salvia>
Pablo Neira Ayuso <pablo@netfilter.org> wrote:
> On Tue, Sep 03, 2019 at 01:46:50PM -0300, Leonardo Bras wrote:
> > On Fri, 2019-08-30 at 22:58 +0200, Florian Westphal wrote:
> > > Leonardo Bras <leonardo@linux.ibm.com> wrote:
> > > > If IPv6 is disabled on boot (ipv6.disable=1), but nft_fib_inet ends up
> > > > dealing with a IPv6 packet, it causes a kernel panic in
> > > > fib6_node_lookup_1(), crashing in bad_page_fault.
> > > >
> > > > The panic is caused by trying to deference a very low address (0x38
> > > > in ppc64le), due to ipv6.fib6_main_tbl = NULL.
> > > > BUG: Kernel NULL pointer dereference at 0x00000038
> > > >
> > > > The kernel panic was reproduced in a host that disabled IPv6 on boot and
> > > > have to process guest packets (coming from a bridge) using it's ip6tables.
> > > >
> > > > Terminate rule evaluation when packet protocol is IPv6 but the ipv6 module
> > > > is not loaded.
> > > >
> > > > Signed-off-by: Leonardo Bras <leonardo@linux.ibm.com>
> > >
> > > Acked-by: Florian Westphal <fw@strlen.de>
> > >
> >
> > Hello Pablo,
> >
> > Any trouble with this patch?
> > I could see the other* one got applied, but not this one.
> > *(The other did not get acked, so i released it alone as v5)
> >
> > Is there any fix I need to do in this one?
>
> Hm, I see, so this one:
>
> https://patchwork.ozlabs.org/patch/1156100/
>
> is not enough?
No, its not.
> I was expecting we could find a way to handle this from br_netfilter
> alone itself.
We can't because we support ipv6 fib lookups from the netdev family
as well.
Alternative is to auto-accept ipv6 packets from the nf_tables eval loop,
but I think its worse.
WARNING: multiple messages have this Message-ID (diff)
From: Florian Westphal <fw@strlen.de>
To: Pablo Neira Ayuso <pablo@netfilter.org>
Cc: Leonardo Bras <leonardo@linux.ibm.com>,
netfilter-devel@vger.kernel.org, coreteam@netfilter.org,
bridge@lists.linux-foundation.org, netdev@vger.kernel.org,
linux-kernel@vger.kernel.org, FlorianWestphal <fw@strlen.de>,
Jozsef Kadlecsik <kadlec@netfilter.org>,
Roopa Prabhu <roopa@cumulusnetworks.com>,
Nikolay Aleksandrov <nikolay@cumulusnetworks.com>,
"David S. Miller" <davem@davemloft.net>
Subject: Re: [PATCH v4 1/2] netfilter: Terminate rule eval if protocol=IPv6 and ipv6 module is disabled
Date: Tue, 3 Sep 2019 19:05:50 +0200 [thread overview]
Message-ID: <20190903170550.GA13660@breakpoint.cc> (raw)
In-Reply-To: <20190903164948.kuvtpy7viqhcmp77@salvia>
Pablo Neira Ayuso <pablo@netfilter.org> wrote:
> On Tue, Sep 03, 2019 at 01:46:50PM -0300, Leonardo Bras wrote:
> > On Fri, 2019-08-30 at 22:58 +0200, Florian Westphal wrote:
> > > Leonardo Bras <leonardo@linux.ibm.com> wrote:
> > > > If IPv6 is disabled on boot (ipv6.disable=1), but nft_fib_inet ends up
> > > > dealing with a IPv6 packet, it causes a kernel panic in
> > > > fib6_node_lookup_1(), crashing in bad_page_fault.
> > > >
> > > > The panic is caused by trying to deference a very low address (0x38
> > > > in ppc64le), due to ipv6.fib6_main_tbl = NULL.
> > > > BUG: Kernel NULL pointer dereference at 0x00000038
> > > >
> > > > The kernel panic was reproduced in a host that disabled IPv6 on boot and
> > > > have to process guest packets (coming from a bridge) using it's ip6tables.
> > > >
> > > > Terminate rule evaluation when packet protocol is IPv6 but the ipv6 module
> > > > is not loaded.
> > > >
> > > > Signed-off-by: Leonardo Bras <leonardo@linux.ibm.com>
> > >
> > > Acked-by: Florian Westphal <fw@strlen.de>
> > >
> >
> > Hello Pablo,
> >
> > Any trouble with this patch?
> > I could see the other* one got applied, but not this one.
> > *(The other did not get acked, so i released it alone as v5)
> >
> > Is there any fix I need to do in this one?
>
> Hm, I see, so this one:
>
> https://patchwork.ozlabs.org/patch/1156100/
>
> is not enough?
No, its not.
> I was expecting we could find a way to handle this from br_netfilter
> alone itself.
We can't because we support ipv6 fib lookups from the netdev family
as well.
Alternative is to auto-accept ipv6 packets from the nf_tables eval loop,
but I think its worse.
next prev parent reply other threads:[~2019-09-03 17:05 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-30 18:13 [Bridge] [PATCH v4 0/2] Drop IPV6 packets if IPv6 is disabled on boot Leonardo Bras
2019-08-30 18:13 ` Leonardo Bras
2019-08-30 18:13 ` [Bridge] [PATCH v4 1/2] netfilter: Terminate rule eval if protocol=IPv6 and ipv6 module is disabled Leonardo Bras
2019-08-30 18:13 ` Leonardo Bras
2019-08-30 20:58 ` [Bridge] " Florian Westphal
2019-08-30 20:58 ` Florian Westphal
2019-09-03 16:46 ` [Bridge] " Leonardo Bras
2019-09-03 16:46 ` Leonardo Bras
2019-09-03 16:49 ` [Bridge] " Pablo Neira Ayuso
2019-09-03 16:49 ` Pablo Neira Ayuso
2019-09-03 16:56 ` [Bridge] " Leonardo Bras
2019-09-03 16:56 ` Leonardo Bras
2019-09-03 17:05 ` Florian Westphal [this message]
2019-09-03 17:05 ` Florian Westphal
2019-09-03 19:31 ` [Bridge] " Pablo Neira Ayuso
2019-09-03 19:31 ` Pablo Neira Ayuso
2019-09-03 19:48 ` [Bridge] " Florian Westphal
2019-09-03 19:48 ` Florian Westphal
2019-09-03 20:19 ` [Bridge] " Pablo Neira Ayuso
2019-09-03 20:19 ` Pablo Neira Ayuso
2019-09-03 20:35 ` [Bridge] " Florian Westphal
2019-09-03 20:35 ` Florian Westphal
2019-09-03 20:55 ` [Bridge] " Pablo Neira Ayuso
2019-09-03 20:55 ` Pablo Neira Ayuso
2019-09-03 20:55 ` [Bridge] " Pablo Neira Ayuso
2019-09-03 20:55 ` Pablo Neira Ayuso
2019-08-30 18:13 ` [Bridge] [PATCH v4 2/2] net: br_netfiler_hooks: Drops IPv6 packets if IPv6 module is not loaded Leonardo Bras
2019-08-30 18:13 ` Leonardo Bras
2019-08-30 20:55 ` [Bridge] " Florian Westphal
2019-08-30 20:55 ` Florian Westphal
2019-08-31 4:42 ` [Bridge] " Leonardo Bras
2019-08-31 4:42 ` Leonardo Bras
2019-08-31 8:43 ` [Bridge] " Florian Westphal
2019-08-31 8:43 ` Florian Westphal
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