diff --git a/net/openvswitch/conntrack.c b/net/openvswitch/conntrack.c
index 8ad1218..a5ec34f 100644
--- a/net/openvswitch/conntrack.c
+++ b/net/openvswitch/conntrack.c
@@ -224,9 +224,6 @@
 	struct nf_conn *ct;
 	int err;
 
-	if (!IS_ENABLED(CONFIG_NF_CONNTRACK_LABELS))
-		return -ENOTSUPP;
-
 	/* The connection could be invalid, in which case set_label is no-op.*/
 	ct = nf_ct_get(skb, &ctinfo);
 	if (!ct)
@@ -587,6 +584,10 @@
 		case OVS_CT_ATTR_MARK: {
 			struct md_mark *mark = nla_data(a);
 
+			if (!mark->mask) {
+				OVS_NLERR(log, "ct_mark mask cannot be 0");
+				return -EINVAL;
+			}
 			info->mark = *mark;
 			break;
 		}
@@ -595,6 +596,10 @@
 		case OVS_CT_ATTR_LABELS: {
 			struct md_labels *labels = nla_data(a);
 
+			if (!labels_nonzero(&labels->mask)) {
+				OVS_NLERR(log, "ct_labels mask cannot be 0");
+				return -EINVAL;
+			}
 			info->labels = *labels;
 			break;
 		}
@@ -705,11 +710,12 @@
 	if (IS_ENABLED(CONFIG_NF_CONNTRACK_ZONES) &&
 	    nla_put_u16(skb, OVS_CT_ATTR_ZONE, ct_info->zone.id))
 		return -EMSGSIZE;
-	if (IS_ENABLED(CONFIG_NF_CONNTRACK_MARK) &&
+	if (IS_ENABLED(CONFIG_NF_CONNTRACK_MARK) && ct_info->mark.mask &&
 	    nla_put(skb, OVS_CT_ATTR_MARK, sizeof(ct_info->mark),
 		    &ct_info->mark))
 		return -EMSGSIZE;
 	if (IS_ENABLED(CONFIG_NF_CONNTRACK_LABELS) &&
+	    labels_nonzero(&ct_info->labels.mask) &&
 	    nla_put(skb, OVS_CT_ATTR_LABELS, sizeof(ct_info->labels),
 		    &ct_info->labels))
 		return -EMSGSIZE;