[PATCH 4.9 44/51] vlan: disable SIOCSHWTSTAMP in container

[Greg Kroah-Hartman]

From: Hangbin Liu <liuhangbin@xxxxxxxxx>

[ Upstream commit 873017af778439f2f8e3d87f28ddb1fcaf244a76 ]

With NET_ADMIN enabled in container, a normal user could be mapped to
root and is able to change the real device's rx filter via ioctl on
vlan, which would affect the other ptp process on host. Fix it by
disabling SIOCSHWTSTAMP in container.

Fixes: a6111d3c93d0 ("vlan: Pass SIOC[SG]HWTSTAMP ioctls to real device")
Signed-off-by: Hangbin Liu <liuhangbin@xxxxxxxxx>
Acked-by: Richard Cochran <richardcochran@xxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 net/8021q/vlan_dev.c |    4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

--- a/net/8021q/vlan_dev.c
+++ b/net/8021q/vlan_dev.c
@@ -366,10 +366,12 @@ static int vlan_dev_ioctl(struct net_dev
 	ifrr.ifr_ifru = ifr->ifr_ifru;
 
 	switch (cmd) {
+	case SIOCSHWTSTAMP:
+		if (!net_eq(dev_net(dev), &init_net))
+			break;
 	case SIOCGMIIPHY:
 	case SIOCGMIIREG:
 	case SIOCSMIIREG:
-	case SIOCSHWTSTAMP:
 	case SIOCGHWTSTAMP:
 		if (netif_device_present(real_dev) && ops->ndo_do_ioctl)
 			err = ops->ndo_do_ioctl(real_dev, &ifrr, cmd);