netfilter: nft_set_rbtree: Add missing expired checks

Expired intervals would still match and be dumped to user space until
garbage collection wiped them out. Make sure they stop matching and
disappear (from users' perspective) as soon as they expire.

Fixes: 8d8540c4 ("netfilter: nft_set_rbtree: add timeout support")
Signed-off-by: NPhil Sutter <phil@nwl.cc>
Signed-off-by: NPablo Neira Ayuso <pablo@netfilter.org>

net/netfilter/nft_set_rbtree.c

@@ -79,6 +79,10 @@ static bool __nft_rbtree_lookup(const struct net *net, const struct nft_set *set
 				parent = rcu_dereference_raw(parent->rb_left);
 				continue;
 			}
+
+			if (nft_set_elem_expired(&rbe->ext))
+				return false;
+
 			if (nft_rbtree_interval_end(rbe)) {
 				if (nft_set_is_anonymous(set))
 					return false;
@@ -94,6 +98,7 @@ static bool __nft_rbtree_lookup(const struct net *net, const struct nft_set *set
 
 	if (set->flags & NFT_SET_INTERVAL && interval != NULL &&
 	    nft_set_elem_active(&interval->ext, genmask) &&
+	    !nft_set_elem_expired(&interval->ext) &&
 	    nft_rbtree_interval_start(interval)) {
 		*ext = &interval->ext;
 		return true;
@@ -154,6 +159,9 @@ static bool __nft_rbtree_get(const struct net *net, const struct nft_set *set,
 				continue;
 			}
 
+			if (nft_set_elem_expired(&rbe->ext))
+				return false;
+
 			if (!nft_set_ext_exists(&rbe->ext, NFT_SET_EXT_FLAGS) ||
 			    (*nft_set_ext_flags(&rbe->ext) & NFT_SET_ELEM_INTERVAL_END) ==
 			    (flags & NFT_SET_ELEM_INTERVAL_END)) {
@@ -170,6 +178,7 @@ static bool __nft_rbtree_get(const struct net *net, const struct nft_set *set,
 
 	if (set->flags & NFT_SET_INTERVAL && interval != NULL &&
 	    nft_set_elem_active(&interval->ext, genmask) &&
+	    !nft_set_elem_expired(&interval->ext) &&
 	    ((!nft_rbtree_interval_end(interval) &&
 	      !(flags & NFT_SET_ELEM_INTERVAL_END)) ||
 	     (nft_rbtree_interval_end(interval) &&
@@ -418,6 +427,8 @@ static void nft_rbtree_walk(const struct nft_ctx *ctx,
 
 		if (iter->count < iter->skip)
 			goto cont;
+		if (nft_set_elem_expired(&rbe->ext))
+			goto cont;
 		if (!nft_set_elem_active(&rbe->ext, iter->genmask))
 			goto cont;