40 lines
1.3 KiB
Diff
40 lines
1.3 KiB
Diff
From: Kevin Cernekee <cernekee@chromium.org>
|
|
Date: Wed, 6 Dec 2017 12:12:27 -0800
|
|
Subject: netlink: Add netns check on taps
|
|
Origin: https://git.kernel.org/linus/93c647643b48f0131f02e45da3bd367d80443291
|
|
Bug-Debian-Security: https://security-tracker.debian.org/tracker/CVE-2017-17449
|
|
|
|
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>
|
|
---
|
|
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))
|