4.14-stable review patch. If anyone has any objections, please let me know.
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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 @@ -254,6 +254,9 @@ 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))