netdev - [PATCH] macvlan: fix netdev feature propagation from lower device

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Date:	Tue, 24 Dec 2013 01:04:29 +0100
From:	Florian Westphal <fw@...len.de>
To:	netdev@...r.kernel.org
Cc:	Florian Westphal <fw@...len.de>,
	"Michael S. Tsirkin" <mst@...hat.com>
Subject: [PATCH] macvlan: fix netdev feature propagation from lower device

There are inconsistencies wrt. feature propagation/inheritance
between the macvlan and the underlying interface.

When a feature is turned off on the real device before a macvlan
is created on top, these will remain enabled on the macvlan device,
whereas turning off the feature on the lower device after macvlan
creation the kernel will propagate the changes to the macvlan.

The second issue is that, when propagating changes from underlying
device to the macvlan interface, macvlan can erronously lose its
NETIF_F_LLTX flag, as features are anded with the underlying device.

However, LLTX should be kept since it has no dependencies on physical
hardware (LLTX is set on macvlan creation regardless of the lower
device properties, see 8ffab51b3dfc54876f145f15b351c41f3f703195
(macvlan: lockless tx path).

Use netdev_increment_features to rebuild the feature set on capability
changes on either the lower device or on the macvlan interface.

The LLTX flag is now forced regardless of user settings in absence of
layer2 hw acceleration (a6cc0cfa72e0b6d9f2c8fd858aa,
net: Add layer 2 hardware acceleration operations for macvlan devices).

Cc: Michael S. Tsirkin <mst@...hat.com>
Signed-off-by: Florian Westphal <fw@...len.de>
---
 drivers/net/macvlan.c | 20 ++++++++++++++++++--
 1 file changed, 18 insertions(+), 2 deletions(-)

diff --git a/drivers/net/macvlan.c b/drivers/net/macvlan.c
index 24ea994..85b4fb4 100644
--- a/drivers/net/macvlan.c
+++ b/drivers/net/macvlan.c
@@ -690,8 +690,19 @@ static netdev_features_t macvlan_fix_features(struct net_device *dev,
 					      netdev_features_t features)
 {
 	struct macvlan_dev *vlan = netdev_priv(dev);
+	netdev_features_t mask;

-	return features & (vlan->set_features | ~MACVLAN_FEATURES);
+	features |= NETIF_F_ALL_FOR_ALL;
+	features &= (vlan->set_features | ~MACVLAN_FEATURES);
+	mask = features;
+
+	features = netdev_increment_features(vlan->lowerdev->features,
+					     features,
+					     mask);
+	if (!vlan->fwd_priv)
+		features |= NETIF_F_LLTX;
+
+	return features;
 }

 static const struct ethtool_ops macvlan_ethtool_ops = {
@@ -1010,7 +1021,12 @@ static int macvlan_device_event(struct notifier_block *unused,
 		break;
 	case NETDEV_FEAT_CHANGE:
 		list_for_each_entry(vlan, &port->vlans, list) {
-			vlan->dev->features = dev->features & MACVLAN_FEATURES;
+			/* macvlan_fix_features will re-test current vlan
+			 * features vs. lowerdev features.
+			 */
+			vlan->dev->features =
+				macvlan_fix_features(vlan->dev,
+						     vlan->dev->features);
 			vlan->dev->gso_max_size = dev->gso_max_size;
 			netdev_features_change(vlan->dev);
 		}
-- 
1.8.1.5

--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html