netfilter: nf_conncount: Fix garbage collection with zones

Currently, we use check_hlist() for garbage colleciton. However, we
use the ‘zone’ from the counted entry to query the existence of
existing entries in the hlist. This could be wrong when they are in
different zones, and this patch fixes this issue.

Fixes: e59ea3df3fc2 ("netfilter: xt_connlimit: honor conntrack zone if available")
Signed-off-by: Yi-Hung Wei <yihung.wei@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
diff --git a/include/net/netfilter/nf_conntrack_count.h b/include/net/netfilter/nf_conntrack_count.h
index 1910b65..3a188a0 100644
--- a/include/net/netfilter/nf_conntrack_count.h
+++ b/include/net/netfilter/nf_conntrack_count.h
@@ -20,7 +20,8 @@
 				 bool *addit);
 
 bool nf_conncount_add(struct hlist_head *head,
-		      const struct nf_conntrack_tuple *tuple);
+		      const struct nf_conntrack_tuple *tuple,
+		      const struct nf_conntrack_zone *zone);
 
 void nf_conncount_cache_free(struct hlist_head *hhead);
 
diff --git a/net/netfilter/nf_conncount.c b/net/netfilter/nf_conncount.c
index 3b5059a..d838360 100644
--- a/net/netfilter/nf_conncount.c
+++ b/net/netfilter/nf_conncount.c
@@ -46,6 +46,7 @@
 struct nf_conncount_tuple {
 	struct hlist_node		node;
 	struct nf_conntrack_tuple	tuple;
+	struct nf_conntrack_zone	zone;
 };
 
 struct nf_conncount_rb {
@@ -80,7 +81,8 @@
 }
 
 bool nf_conncount_add(struct hlist_head *head,
-		      const struct nf_conntrack_tuple *tuple)
+		      const struct nf_conntrack_tuple *tuple,
+		      const struct nf_conntrack_zone *zone)
 {
 	struct nf_conncount_tuple *conn;
 
@@ -88,6 +90,7 @@
 	if (conn == NULL)
 		return false;
 	conn->tuple = *tuple;
+	conn->zone = *zone;
 	hlist_add_head(&conn->node, head);
 	return true;
 }
@@ -108,7 +111,7 @@
 
 	/* check the saved connections */
 	hlist_for_each_entry_safe(conn, n, head, node) {
-		found = nf_conntrack_find_get(net, zone, &conn->tuple);
+		found = nf_conntrack_find_get(net, &conn->zone, &conn->tuple);
 		if (found == NULL) {
 			hlist_del(&conn->node);
 			kmem_cache_free(conncount_conn_cachep, conn);
@@ -117,7 +120,8 @@
 
 		found_ct = nf_ct_tuplehash_to_ctrack(found);
 
-		if (tuple && nf_ct_tuple_equal(&conn->tuple, tuple)) {
+		if (tuple && nf_ct_tuple_equal(&conn->tuple, tuple) &&
+		    nf_ct_zone_equal(found_ct, zone, zone->dir)) {
 			/*
 			 * Just to be sure we have it only once in the list.
 			 * We should not see tuples twice unless someone hooks
@@ -196,7 +200,7 @@
 			if (!addit)
 				return count;
 
-			if (!nf_conncount_add(&rbconn->hhead, tuple))
+			if (!nf_conncount_add(&rbconn->hhead, tuple, zone))
 				return 0; /* hotdrop */
 
 			return count + 1;
@@ -238,6 +242,7 @@
 	}
 
 	conn->tuple = *tuple;
+	conn->zone = *zone;
 	memcpy(rbconn->key, key, sizeof(u32) * keylen);
 
 	INIT_HLIST_HEAD(&rbconn->hhead);
diff --git a/net/netfilter/nft_connlimit.c b/net/netfilter/nft_connlimit.c
index 50c068d..a832c59 100644
--- a/net/netfilter/nft_connlimit.c
+++ b/net/netfilter/nft_connlimit.c
@@ -52,7 +52,7 @@
 	if (!addit)
 		goto out;
 
-	if (!nf_conncount_add(&priv->hhead, tuple_ptr)) {
+	if (!nf_conncount_add(&priv->hhead, tuple_ptr, zone)) {
 		regs->verdict.code = NF_DROP;
 		spin_unlock_bh(&priv->lock);
 		return;