[PATCH -stable,4.19 08/10] netfilter: nf_tables: reject unbound anonymous set before commit phase

[Pablo Neira Ayuso <pablo@xxxxxxxxxxxxx>]

[ 938154b93be8cd611ddfd7bafc1849f3c4355201 ]

Add a new list to track set transaction and to check for unbound
anonymous sets before entering the commit phase.

Bail out at the end of the transaction handling if an anonymous set
remains unbound.

Fixes: 96518518cc41 ("netfilter: add nftables")
Signed-off-by: Pablo Neira Ayuso <pablo@xxxxxxxxxxxxx>
---
 include/net/netfilter/nf_tables.h |  3 +++
 net/netfilter/nf_tables_api.c     | 33 ++++++++++++++++++++++++++++---
 2 files changed, 33 insertions(+), 3 deletions(-)

diff --git a/include/net/netfilter/nf_tables.h b/include/net/netfilter/nf_tables.h
index a65c784aae5b..471944087372 100644
--- a/include/net/netfilter/nf_tables.h
+++ b/include/net/netfilter/nf_tables.h
@@ -1320,12 +1320,14 @@ static inline void nft_set_elem_clear_busy(struct nft_set_ext *ext)
  *	struct nft_trans - nf_tables object update in transaction
  *
  *	@list: used internally
+ *	@binding_list: list of objects with possible bindings
  *	@msg_type: message type
  *	@ctx: transaction context
  *	@data: internal information related to the transaction
  */
 struct nft_trans {
 	struct list_head		list;
+	struct list_head		binding_list;
 	int				msg_type;
 	struct nft_ctx			ctx;
 	char				data[0];
@@ -1413,6 +1415,7 @@ void nft_chain_filter_fini(void);
 struct nftables_pernet {
 	struct list_head	tables;
 	struct list_head	commit_list;
+	struct list_head	binding_list;
 	struct list_head	module_list;
 	struct list_head	notify_list;
 	struct mutex		commit_mutex;
diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c
index 22fd3598621e..7d275e81fa6e 100644
--- a/net/netfilter/nf_tables_api.c
+++ b/net/netfilter/nf_tables_api.c
@@ -102,6 +102,7 @@ static struct nft_trans *nft_trans_alloc_gfp(const struct nft_ctx *ctx,
 		return NULL;
 
 	INIT_LIST_HEAD(&trans->list);
+	INIT_LIST_HEAD(&trans->binding_list);
 	trans->msg_type = msg_type;
 	trans->ctx	= *ctx;
 
@@ -114,9 +115,15 @@ static struct nft_trans *nft_trans_alloc(const struct nft_ctx *ctx,
 	return nft_trans_alloc_gfp(ctx, msg_type, size, GFP_KERNEL);
 }
 
-static void nft_trans_destroy(struct nft_trans *trans)
+static void nft_trans_list_del(struct nft_trans *trans)
 {
 	list_del(&trans->list);
+	list_del(&trans->binding_list);
+}
+
+static void nft_trans_destroy(struct nft_trans *trans)
+{
+	nft_trans_list_del(trans);
 	kfree(trans);
 }
 
@@ -160,6 +167,13 @@ static void nft_trans_commit_list_add_tail(struct net *net, struct nft_trans *tr
 	struct nftables_pernet *nft_net;
 
 	nft_net = net_generic(net, nf_tables_net_id);
+	switch (trans->msg_type) {
+	case NFT_MSG_NEWSET:
+		if (nft_set_is_anonymous(nft_trans_set(trans)))
+			list_add_tail(&trans->binding_list, &nft_net->binding_list);
+		break;
+	}
+
 	list_add_tail(&trans->list, &nft_net->commit_list);
 }
 
@@ -6403,7 +6417,7 @@ static void nf_tables_commit_release(struct net *net)
 	synchronize_rcu();
 
 	list_for_each_entry_safe(trans, next, &nft_net->commit_list, list) {
-		list_del(&trans->list);
+		nft_trans_list_del(trans);
 		nft_commit_release(trans);
 	}
 }
@@ -6542,6 +6556,18 @@ static int nf_tables_commit(struct net *net, struct sk_buff *skb)
 	struct nft_chain *chain;
 	struct nft_table *table;
 
+	list_for_each_entry(trans, &nft_net->binding_list, binding_list) {
+		switch (trans->msg_type) {
+		case NFT_MSG_NEWSET:
+			if (nft_set_is_anonymous(nft_trans_set(trans)) &&
+			    !nft_trans_set_bound(trans)) {
+				pr_warn_once("nftables ruleset with unbound set\n");
+				return -EINVAL;
+			}
+			break;
+		}
+	}
+
 	/* 0. Validate ruleset, otherwise roll back for error reporting. */
 	if (nf_tables_validate(net) < 0)
 		return -EAGAIN;
@@ -6847,7 +6873,7 @@ static int __nf_tables_abort(struct net *net)
 
 	list_for_each_entry_safe_reverse(trans, next,
 					 &nft_net->commit_list, list) {
-		list_del(&trans->list);
+		nft_trans_list_del(trans);
 		nf_tables_abort_release(trans);
 	}
 
@@ -7497,6 +7523,7 @@ static int __net_init nf_tables_init_net(struct net *net)
 
 	INIT_LIST_HEAD(&nft_net->tables);
 	INIT_LIST_HEAD(&nft_net->commit_list);
+	INIT_LIST_HEAD(&nft_net->binding_list);
 	mutex_init(&nft_net->commit_mutex);
 	nft_net->base_seq = 1;
 	nft_net->validate_state = NFT_VALIDATE_SKIP;
-- 
2.30.2