Patch "netlink: Add netns check on taps" has been added to the 4.9-stable tree

[<gregkh@linuxfoundation.org>]

This is a note to let you know that I've just added the patch titled

    netlink: Add netns check on taps

to the 4.9-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     netlink-add-netns-check-on-taps.patch
and it can be found in the queue-4.9 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From foo@baz Sun Dec 31 11:13:15 CET 2017
From: Kevin Cernekee <cernekee@chromium.org>
Date: Wed, 6 Dec 2017 12:12:27 -0800
Subject: netlink: Add netns check on taps

From: Kevin Cernekee <cernekee@chromium.org>


[ Upstream commit 93c647643b48f0131f02e45da3bd367d80443291 ]

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 <cernekee@chromium.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 net/netlink/af_netlink.c |    3 +++
 1 file changed, 3 insertions(+)

--- a/net/netlink/af_netlink.c
+++ b/net/netlink/af_netlink.c
@@ -261,6 +261,9 @@ static int __netlink_deliver_tap_skb(str
 	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))


Patches currently in stable-queue which might be from cernekee@chromium.org are

queue-4.9/net-igmp-use-correct-source-address-on-igmpv3-reports.patch
queue-4.9/netlink-add-netns-check-on-taps.patch