[PATCH] net: ipv6: check net in ip6_call_ra_chain

[PATCH] net: ipv6: check net in ip6_call_ra_chain

[Francesco Ruggeri]

ip6_call_ra_chain is called when IPv6 packet with Router Alert option
is forwarded.
It needs to check if the net of the socket is the same as the net of the
input device, otherwise the packet gets delivered to every IPv6 socket
listening for Router Alerts, no matter which network namespace it is in.

Suggested-by: Maxim Martynov <maxim@arista.com>
Signed-off-by: Maxim Martynov <maxim@arista.com>
Signed-off-by: Francesco Ruggeri <fruggeri@arista.com>

---
 net/ipv6/ip6_output.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/net/ipv6/ip6_output.c b/net/ipv6/ip6_output.c
index 5f9fa0302b5a..3ed25e17dff3 100644
--- a/net/ipv6/ip6_output.c
+++ b/net/ipv6/ip6_output.c
@@ -299,7 +299,8 @@ static int ip6_call_ra_chain(struct sk_buff *skb, int sel)
 		struct sock *sk = ra->sk;
 		if (sk && ra->sel == sel &&
 		    (!sk->sk_bound_dev_if ||
-		     sk->sk_bound_dev_if == skb->dev->ifindex)) {
+		     sk->sk_bound_dev_if == skb->dev->ifindex) &&
+		    net_eq(sock_net(sk), dev_net(skb->dev))) {
 			if (last) {
 				struct sk_buff *skb2 = skb_clone(skb, GFP_ATOMIC);
 				if (skb2)
-- 
2.19.1

Re: [PATCH] net: ipv6: check net in ip6_call_ra_chain

[David Miller]

From: fruggeri@arista.com (Francesco Ruggeri)
Date: Thu, 28 Feb 2019 11:01:46 -0800

> ip6_call_ra_chain is called when IPv6 packet with Router Alert option
> is forwarded.
> It needs to check if the net of the socket is the same as the net of the
> input device, otherwise the packet gets delivered to every IPv6 socket
> listening for Router Alerts, no matter which network namespace it is in.
> 
> Suggested-by: Maxim Martynov <maxim@arista.com>
> Signed-off-by: Maxim Martynov <maxim@arista.com>
> Signed-off-by: Francesco Ruggeri <fruggeri@arista.com>

Right now someone using such a tool does get all RAs in the system.

Your change not only breaks them, but also gives them no method by
which to keep obtaining the same behavior.

I don't know what to do or suggest in this situation, but right now
I'm putting this patch on hold.

Re: [PATCH] net: ipv6: check net in ip6_call_ra_chain

[David Ahern]

On 2/28/19 2:02 PM, David Miller wrote:
> From: fruggeri@arista.com (Francesco Ruggeri)
> Date: Thu, 28 Feb 2019 11:01:46 -0800
> 
>> ip6_call_ra_chain is called when IPv6 packet with Router Alert option
>> is forwarded.
>> It needs to check if the net of the socket is the same as the net of the
>> input device, otherwise the packet gets delivered to every IPv6 socket
>> listening for Router Alerts, no matter which network namespace it is in.
>>
>> Suggested-by: Maxim Martynov <maxim@arista.com>
>> Signed-off-by: Maxim Martynov <maxim@arista.com>
>> Signed-off-by: Francesco Ruggeri <fruggeri@arista.com>
> 
> Right now someone using such a tool does get all RAs in the system.
> 
> Your change not only breaks them, but also gives them no method by
> which to keep obtaining the same behavior.
> 
> I don't know what to do or suggest in this situation, but right now
> I'm putting this patch on hold.
> 

need an equivalent to NETLINK_LISTEN_ALL_NSID

Re: [PATCH] net: ipv6: check net in ip6_call_ra_chain

[Francesco Ruggeri]

On Thu, Feb 28, 2019 at 3:31 PM David Ahern <dsahern@gmail.com> wrote:
>
> On 2/28/19 2:02 PM, David Miller wrote:
> > From: fruggeri@arista.com (Francesco Ruggeri)
> > Date: Thu, 28 Feb 2019 11:01:46 -0800
> >
> >> ip6_call_ra_chain is called when IPv6 packet with Router Alert option
> >> is forwarded.
> >> It needs to check if the net of the socket is the same as the net of the
> >> input device, otherwise the packet gets delivered to every IPv6 socket
> >> listening for Router Alerts, no matter which network namespace it is in.
> >>
> >> Suggested-by: Maxim Martynov <maxim@arista.com>
> >> Signed-off-by: Maxim Martynov <maxim@arista.com>
> >> Signed-off-by: Francesco Ruggeri <fruggeri@arista.com>
> >
> > Right now someone using such a tool does get all RAs in the system.
> >
> > Your change not only breaks them, but also gives them no method by
> > which to keep obtaining the same behavior.
> >
> > I don't know what to do or suggest in this situation, but right now
> > I'm putting this patch on hold.
> >
>
> need an equivalent to NETLINK_LISTEN_ALL_NSID

If that would be acceptable, we can look into it.

Thanks,
Francesco

Re: [PATCH] net: ipv6: check net in ip6_call_ra_chain

[David Miller]

From: Francesco Ruggeri <fruggeri@arista.com>
Date: Thu, 28 Feb 2019 16:09:17 -0800

> On Thu, Feb 28, 2019 at 3:31 PM David Ahern <dsahern@gmail.com> wrote:
>>
>> On 2/28/19 2:02 PM, David Miller wrote:
>> > From: fruggeri@arista.com (Francesco Ruggeri)
>> > Date: Thu, 28 Feb 2019 11:01:46 -0800
>> >
>> >> ip6_call_ra_chain is called when IPv6 packet with Router Alert option
>> >> is forwarded.
>> >> It needs to check if the net of the socket is the same as the net of the
>> >> input device, otherwise the packet gets delivered to every IPv6 socket
>> >> listening for Router Alerts, no matter which network namespace it is in.
>> >>
>> >> Suggested-by: Maxim Martynov <maxim@arista.com>
>> >> Signed-off-by: Maxim Martynov <maxim@arista.com>
>> >> Signed-off-by: Francesco Ruggeri <fruggeri@arista.com>
>> >
>> > Right now someone using such a tool does get all RAs in the system.
>> >
>> > Your change not only breaks them, but also gives them no method by
>> > which to keep obtaining the same behavior.
>> >
>> > I don't know what to do or suggest in this situation, but right now
>> > I'm putting this patch on hold.
>> >
>>
>> need an equivalent to NETLINK_LISTEN_ALL_NSID
> 
> If that would be acceptable, we can look into it.

It is.