Patch "macvlan: filter out unsupported feature flags" has been added to the 4.14-stable tree

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

macvlan: filter out unsupported feature flags

to the 4.14-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:
macvlan-filter-out-unsupported-feature-flags.patch
and it can be found in the queue-4.14 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Shannon Nelson <[email protected]>
Date: Thu, 8 Mar 2018 16:17:23 -0800
Subject: macvlan: filter out unsupported feature flags

From: Shannon Nelson <[email protected]>

[ Upstream commit 13fbcc8dc573482dd3f27568257fd7087f8935f4 ]

Adding a macvlan device on top of a lowerdev that supports the xfrm offloads fails with a new regression:

  # ip link add link ens1f0 mv0 type macvlan
  RTNETLINK answers: Operation not permitted

Tracing down the failure shows that the macvlan device inherits the NETIF_F_HW_ESP and NETIF_F_HW_ESP_TX_CSUM feature flags from the lowerdev, but with no dev->xfrmdev_ops API filled in, it doesn't actually support xfrm. When the request is made to add the new macvlan device, the XFRM listener for NETDEV_REGISTER calls xfrm_api_check() which fails the new registration because dev->xfrmdev_ops is NULL.

The macvlan creation succeeds when we filter out the ESP feature flags in macvlan_fix_features(), so let's filter them out like we're already filtering out ~NETIF_F_NETNS_LOCAL. When XFRM support is added in the future, we can add the flags into MACVLAN_FEATURES.

This same problem could crop up in the future with any other new feature flags, so let's filter out any flags that aren't defined as supported in macvlan.

---
 drivers/net/macvlan.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

@@ -1037,7 +1037,7 @@ static netdev_features_t macvlan_fix_fea
 	lowerdev_features &= (features | ~NETIF_F_LRO);
 	features = netdev_increment_features(lowerdev_features, features, mask);
 	features |= ALWAYS_ON_FEATURES;
-	features &= ~NETIF_F_NETNS_LOCAL;
+	features &= (ALWAYS_ON_FEATURES | MACVLAN_FEATURES);
 
 	return features;
 }

Patches currently in stable-queue which might be from [email protected] are

queue-4.14/macvlan-filter-out-unsupported-feature-flags.patch