netfilter: nf_tables: reject unbound anonymous set before commit phase

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@netfilter.org>

1 files changed, 32 insertions, 3 deletions

diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c
index 6f26520bd86506..66da44bff5e497 100644
--- a/net/netfilter/nf_tables_api.c
+++ b/net/netfilter/nf_tables_api.c
@@ -151,6 +151,7 @@ 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;
 
@@ -163,9 +164,15 @@ 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);
 }
 
@@ -357,6 +364,14 @@ static void nft_trans_commit_list_add_tail(struct net *net, struct nft_trans *tr
 {
 	struct nftables_pernet *nft_net = nft_pernet(net);
 
+	switch (trans->msg_type) {
+	case NFT_MSG_NEWSET:
+		if (!nft_trans_set_update(trans) &&
+		    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);
 }
 
@@ -9111,7 +9126,7 @@ static void nf_tables_trans_destroy_work(struct work_struct *w)
 	synchronize_rcu();
 
 	list_for_each_entry_safe(trans, next, &head, list) {
-		list_del(&trans->list);
+		nft_trans_list_del(trans);
 		nft_commit_release(trans);
 	}
 }
@@ -9476,6 +9491,19 @@ static int nf_tables_commit(struct net *net, struct sk_buff *skb)
 		return 0;
 	}
 
+	list_for_each_entry(trans, &nft_net->binding_list, binding_list) {
+		switch (trans->msg_type) {
+		case NFT_MSG_NEWSET:
+			if (!nft_trans_set_update(trans) &&
+			    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;
@@ -9989,7 +10017,7 @@ static int __nf_tables_abort(struct net *net, enum nfnl_abort_action action)
 
 	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);
 	}
 
@@ -10765,6 +10793,7 @@ 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);
 	INIT_LIST_HEAD(&nft_net->module_list);
 	INIT_LIST_HEAD(&nft_net->notify_list);
 	mutex_init(&nft_net->commit_mutex);