netfilter: ipset: send nonzero skbinfo extensions only

Do not send zero valued skbinfo extensions to userspace at listing.
Signed-off-by: Jozsef Kadlecsik <kadlec@blackhole.kfki.hu>

include/linux/netfilter/ipset/ip_set.h

@@ -335,13 +335,17 @@ ip_set_get_skbinfo(struct ip_set_skbinfo *skbinfo,
 static inline bool
 ip_set_put_skbinfo(struct sk_buff *skb, struct ip_set_skbinfo *skbinfo)
 {
-	return nla_put_net64(skb, IPSET_ATTR_SKBMARK,
-			     cpu_to_be64((u64)skbinfo->skbmark << 32 |
-					 skbinfo->skbmarkmask)) ||
-	       nla_put_net32(skb, IPSET_ATTR_SKBPRIO,
-			     cpu_to_be32(skbinfo->skbprio)) ||
-	       nla_put_net16(skb, IPSET_ATTR_SKBQUEUE,
-			     cpu_to_be16(skbinfo->skbqueue));
+	/* Send nonzero parameters only */
+	return ((skbinfo->skbmark || skbinfo->skbmarkmask) &&
+		nla_put_net64(skb, IPSET_ATTR_SKBMARK,
+			      cpu_to_be64((u64)skbinfo->skbmark << 32 |
+					  skbinfo->skbmarkmask))) ||
+	       (skbinfo->skbprio &&
+	        nla_put_net32(skb, IPSET_ATTR_SKBPRIO,
+			      cpu_to_be32(skbinfo->skbprio))) ||
+	       (skbinfo->skbqueue &&
+	        nla_put_net16(skb, IPSET_ATTR_SKBQUEUE,
+			     cpu_to_be16(skbinfo->skbqueue)));
 
 }