Currently, a nlmon link inside a child namespace can observe systemwide
netlink activity. Filter the traffic so that nlmon can only sniff
netlink messages from its own netns.
Test case:
vpnns -- bash -c "ip link add nlmon0 type nlmon; \
ip link set nlmon0 up; \
tcpdump -i nlmon0 -q -w /tmp/nlmon.pcap -U" &
sudo ip xfrm state add src 10.1.1.1 dst 10.1.1.2 proto esp \
spi 0x1 mode transport \
auth sha1 0x6162633132330000000000000000000000000000 \
enc aes 0x00000000000000000000000000000000
grep --binary abc123 /tmp/nlmon.pcap
Signed-off-by: Kevin Cernekee <[email protected]>
---
net/netlink/af_netlink.c | 3 +++
1 file changed, 3 insertions(+)
V1->V2: Drop the special exception for init_net.
Compile-tested only, will retest later today.
diff --git a/net/netlink/af_netlink.c b/net/netlink/af_netlink.c
index b9e0ee4..79cc1bf 100644
--- a/net/netlink/af_netlink.c
+++ b/net/netlink/af_netlink.c
@@ -253,6 +253,9 @@ static int __netlink_deliver_tap_skb(struct sk_buff *skb,
struct sock *sk = skb->sk;
int ret = -ENOMEM;
+ if (!net_eq(dev_net(dev), sock_net(sk)))
+ return 0;
+
dev_hold(dev);
if (is_vmalloc_addr(skb->head))
--
2.7.4
From: Kevin Cernekee <[email protected]>
Date: Wed, 6 Dec 2017 12:12:27 -0800
> Currently, a nlmon link inside a child namespace can observe systemwide
> netlink activity. Filter the traffic so that nlmon can only sniff
> netlink messages from its own netns.
>
> Test case:
>
> vpnns -- bash -c "ip link add nlmon0 type nlmon; \
> ip link set nlmon0 up; \
> tcpdump -i nlmon0 -q -w /tmp/nlmon.pcap -U" &
> sudo ip xfrm state add src 10.1.1.1 dst 10.1.1.2 proto esp \
> spi 0x1 mode transport \
> auth sha1 0x6162633132330000000000000000000000000000 \
> enc aes 0x00000000000000000000000000000000
> grep --binary abc123 /tmp/nlmon.pcap
>
> Signed-off-by: Kevin Cernekee <[email protected]>
Applied and queued up for -stable, thanks Kevin.
On Wed, Dec 06, 2017 at 03:57:14PM -0500, David Miller wrote:
> From: Kevin Cernekee <[email protected]>
> Date: Wed, 6 Dec 2017 12:12:27 -0800
>
> > Currently, a nlmon link inside a child namespace can observe systemwide
> > netlink activity. Filter the traffic so that nlmon can only sniff
> > netlink messages from its own netns.
> >
> > Test case:
> >
> > vpnns -- bash -c "ip link add nlmon0 type nlmon; \
> > ip link set nlmon0 up; \
> > tcpdump -i nlmon0 -q -w /tmp/nlmon.pcap -U" &
> > sudo ip xfrm state add src 10.1.1.1 dst 10.1.1.2 proto esp \
> > spi 0x1 mode transport \
> > auth sha1 0x6162633132330000000000000000000000000000 \
> > enc aes 0x00000000000000000000000000000000
> > grep --binary abc123 /tmp/nlmon.pcap
> >
> > Signed-off-by: Kevin Cernekee <[email protected]>
>
> Applied and queued up for -stable, thanks Kevin.
David,
this patch is marked as accepted in patchworks and listed in
http://patchwork.ozlabs.org/bundle/davem/stable/?state=*
but it's not in the net tree. Is there a problem with it?
Michal Kubecek
From: Michal Kubecek <[email protected]>
Date: Mon, 11 Dec 2017 17:13:50 +0100
> On Wed, Dec 06, 2017 at 03:57:14PM -0500, David Miller wrote:
>> From: Kevin Cernekee <[email protected]>
>> Date: Wed, 6 Dec 2017 12:12:27 -0800
>>
>> > Currently, a nlmon link inside a child namespace can observe systemwide
>> > netlink activity. Filter the traffic so that nlmon can only sniff
>> > netlink messages from its own netns.
>> >
>> > Test case:
>> >
>> > vpnns -- bash -c "ip link add nlmon0 type nlmon; \
>> > ip link set nlmon0 up; \
>> > tcpdump -i nlmon0 -q -w /tmp/nlmon.pcap -U" &
>> > sudo ip xfrm state add src 10.1.1.1 dst 10.1.1.2 proto esp \
>> > spi 0x1 mode transport \
>> > auth sha1 0x6162633132330000000000000000000000000000 \
>> > enc aes 0x00000000000000000000000000000000
>> > grep --binary abc123 /tmp/nlmon.pcap
>> >
>> > Signed-off-by: Kevin Cernekee <[email protected]>
>>
>> Applied and queued up for -stable, thanks Kevin.
>
> David,
>
> this patch is marked as accepted in patchworks and listed in
>
> http://patchwork.ozlabs.org/bundle/davem/stable/?state=*
>
> but it's not in the net tree. Is there a problem with it?
Sorry, it should be there now.
Thanks.
On Mon, Dec 11, 2017 at 11:58:37AM -0500, David Miller wrote:
> From: Michal Kubecek <[email protected]>
> Date: Mon, 11 Dec 2017 17:13:50 +0100
>
> > On Wed, Dec 06, 2017 at 03:57:14PM -0500, David Miller wrote:
> >> From: Kevin Cernekee <[email protected]>
> >> Date: Wed, 6 Dec 2017 12:12:27 -0800
> >>
> >> > Currently, a nlmon link inside a child namespace can observe systemwide
> >> > netlink activity. Filter the traffic so that nlmon can only sniff
> >> > netlink messages from its own netns.
> >> >
> >> > Test case:
> >> >
> >> > vpnns -- bash -c "ip link add nlmon0 type nlmon; \
> >> > ip link set nlmon0 up; \
> >> > tcpdump -i nlmon0 -q -w /tmp/nlmon.pcap -U" &
> >> > sudo ip xfrm state add src 10.1.1.1 dst 10.1.1.2 proto esp \
> >> > spi 0x1 mode transport \
> >> > auth sha1 0x6162633132330000000000000000000000000000 \
> >> > enc aes 0x00000000000000000000000000000000
> >> > grep --binary abc123 /tmp/nlmon.pcap
> >> >
> >> > Signed-off-by: Kevin Cernekee <[email protected]>
> >>
> >> Applied and queued up for -stable, thanks Kevin.
> >
> > David,
> >
> > this patch is marked as accepted in patchworks and listed in
> >
> > http://patchwork.ozlabs.org/bundle/davem/stable/?state=*
> >
> > but it's not in the net tree. Is there a problem with it?
>
> Sorry, it should be there now.
Thank you,
Michal Kubecek