netdev - [PATCH net-next] openvswitch: Only set mark and labels when commiting a connection.

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Message-Id: <1466468378-32235-1-git-send-email-jarno@ovn.org>
Date:	Mon, 20 Jun 2016 17:19:38 -0700
From:	Jarno Rajahalme <jarno@....org>
To:	netdev@...r.kernel.org
Cc:	dev@...nvswitch.org, jarno@....org
Subject: [PATCH net-next] openvswitch: Only set mark and labels when commiting a connection.

Only allow setting conntrack mark or labels when the commit flag is
specified.  This makes sure we can not set them before the connection
has been persisted, as in that case the mark and labels would be lost
in an event of an userspace upcall.

OVS userspace already requires the commit flag to accept setting
ct_mark and/or ct_labels.  Validate for this on the kernel API.

Finally, set conntrack mark and labels right before committing so that
the initial conntrack NEW event has the mark and labels.

Signed-off-by: Jarno Rajahalme <jarno@....org>
---
 net/openvswitch/conntrack.c | 72 ++++++++++++++++++++++++++++++---------------
 1 file changed, 48 insertions(+), 24 deletions(-)

diff --git a/net/openvswitch/conntrack.c b/net/openvswitch/conntrack.c
index 3d5feed..f1612f5 100644
--- a/net/openvswitch/conntrack.c
+++ b/net/openvswitch/conntrack.c
@@ -824,6 +824,17 @@ static int ovs_ct_lookup(struct net *net, struct sw_flow_key *key,
 	return 0;
 }
 
+static bool labels_nonzero(const struct ovs_key_ct_labels *labels)
+{
+	size_t i;
+
+	for (i = 0; i < sizeof(*labels); i++)
+		if (labels->ct_labels[i])
+			return true;
+
+	return false;
+}
+
 /* Lookup connection and confirm if unconfirmed. */
 static int ovs_ct_commit(struct net *net, struct sw_flow_key *key,
 			 const struct ovs_conntrack_info *info,
@@ -834,24 +845,35 @@ static int ovs_ct_commit(struct net *net, struct sw_flow_key *key,
 	err = __ovs_ct_lookup(net, key, info, skb);
 	if (err)
 		return err;
-	/* This is a no-op if the connection has already been confirmed. */
+
+	/* As any changes to an unconfirmed connection may be lost due
+	 * to an upcall, we require the presence of the 'commit' flag
+	 * for setting mask and/or labels.  Perform the changes before
+	 * confirming the connection so that the initial mark and label
+	 * values are present in the initial CT NEW netlink event.
+	 */
+	if (info->mark.mask) {
+		err = ovs_ct_set_mark(skb, key, info->mark.value,
+				      info->mark.mask);
+		if (err)
+			return err;
+	}
+	if (labels_nonzero(&info->labels.mask)) {
+		err = ovs_ct_set_labels(skb, key, &info->labels.value,
+					&info->labels.mask);
+		if (err)
+			return err;
+	}
+
+	/* Will take care of sending queued events even if the connection is
+	 * already confirmed.
+	 */
 	if (nf_conntrack_confirm(skb) != NF_ACCEPT)
 		return -EINVAL;
 
 	return 0;
 }
 
-static bool labels_nonzero(const struct ovs_key_ct_labels *labels)
-{
-	size_t i;
-
-	for (i = 0; i < sizeof(*labels); i++)
-		if (labels->ct_labels[i])
-			return true;
-
-	return false;
-}
-
 /* Returns 0 on success, -EINPROGRESS if 'skb' is stolen, or other nonzero
  * value if 'skb' is freed.
  */
@@ -876,19 +898,7 @@ int ovs_ct_execute(struct net *net, struct sk_buff *skb,
 		err = ovs_ct_commit(net, key, info, skb);
 	else
 		err = ovs_ct_lookup(net, key, info, skb);
-	if (err)
-		goto err;
 
-	if (info->mark.mask) {
-		err = ovs_ct_set_mark(skb, key, info->mark.value,
-				      info->mark.mask);
-		if (err)
-			goto err;
-	}
-	if (labels_nonzero(&info->labels.mask))
-		err = ovs_ct_set_labels(skb, key, &info->labels.value,
-					&info->labels.mask);
-err:
 	skb_push(skb, nh_ofs);
 	if (err)
 		kfree_skb(skb);
@@ -1145,6 +1155,20 @@ static int parse_ct(const struct nlattr *attr, struct ovs_conntrack_info *info,
 		}
 	}
 
+#ifdef CONFIG_NF_CONNTRACK_MARK
+	if (!info->commit && info->mark.mask) {
+		OVS_NLERR(log,
+			  "Setting conntrack mark requires 'commit' flag.");
+		return -EINVAL;
+	}
+#endif
+#ifdef CONFIG_NF_CONNTRACK_LABELS
+	if (!info->commit && labels_nonzero(&info->labels.mask)) {
+		OVS_NLERR(log,
+			  "Setting conntrack labels requires 'commit' flag.");
+		return -EINVAL;
+	}
+#endif
 	if (rem > 0) {
 		OVS_NLERR(log, "Conntrack attr has %d unknown bytes", rem);
 		return -EINVAL;
-- 
2.1.4