netfilter: nf_tables: validate catch-all set elements

catch-all set element might jump/goto to chain that uses expressions
that require validation.

Fixes: aaa31047a6d2 ("netfilter: nftables: add catch-all set element support")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

1 files changed, 58 insertions, 6 deletions

diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c
index cd52109e674a2..98043e83af717 100644
--- a/net/netfilter/nf_tables_api.c
+++ b/net/netfilter/nf_tables_api.c
@@ -3447,6 +3447,64 @@ static int nft_table_validate(struct net *net, const struct nft_table *table)
 	return 0;
 }
 
+int nft_setelem_validate(const struct nft_ctx *ctx, struct nft_set *set,
+			 const struct nft_set_iter *iter,
+			 struct nft_set_elem *elem)
+{
+	const struct nft_set_ext *ext = nft_set_elem_ext(set, elem->priv);
+	struct nft_ctx *pctx = (struct nft_ctx *)ctx;
+	const struct nft_data *data;
+	int err;
+
+	if (nft_set_ext_exists(ext, NFT_SET_EXT_FLAGS) &&
+	    *nft_set_ext_flags(ext) & NFT_SET_ELEM_INTERVAL_END)
+		return 0;
+
+	data = nft_set_ext_data(ext);
+	switch (data->verdict.code) {
+	case NFT_JUMP:
+	case NFT_GOTO:
+		pctx->level++;
+		err = nft_chain_validate(ctx, data->verdict.chain);
+		if (err < 0)
+			return err;
+		pctx->level--;
+		break;
+	default:
+		break;
+	}
+
+	return 0;
+}
+
+struct nft_set_elem_catchall {
+	struct list_head	list;
+	struct rcu_head		rcu;
+	void			*elem;
+};
+
+int nft_set_catchall_validate(const struct nft_ctx *ctx, struct nft_set *set)
+{
+	u8 genmask = nft_genmask_next(ctx->net);
+	struct nft_set_elem_catchall *catchall;
+	struct nft_set_elem elem;
+	struct nft_set_ext *ext;
+	int ret = 0;
+
+	list_for_each_entry_rcu(catchall, &set->catchall_list, list) {
+		ext = nft_set_elem_ext(set, catchall->elem);
+		if (!nft_set_elem_active(ext, genmask))
+			continue;
+
+		elem.priv = catchall->elem;
+		ret = nft_setelem_validate(ctx, set, NULL, &elem);
+		if (ret < 0)
+			return ret;
+	}
+
+	return ret;
+}
+
 static struct nft_rule *nft_rule_lookup_byid(const struct net *net,
 					     const struct nft_chain *chain,
 					     const struct nlattr *nla);
@@ -4759,12 +4817,6 @@ err_set_name:
 	return err;
 }
 
-struct nft_set_elem_catchall {
-	struct list_head	list;
-	struct rcu_head		rcu;
-	void			*elem;
-};
-
 static void nft_set_catchall_destroy(const struct nft_ctx *ctx,
 				     struct nft_set *set)
 {