[PATCH nf 4/6] netfilter: nf_tables: reject unbound chain set before commit phase

[Pablo Neira Ayuso <pablo@netfilter.org>]

Use binding list to track set transaction and to check for unbound
chains before entering the commit phase.

Bail out if chain binding remain unused before entering the commit
step.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
---
 net/netfilter/nf_tables_api.c | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c
index 92cc9141de5d..a4f1a9f3d6d4 100644
--- a/net/netfilter/nf_tables_api.c
+++ b/net/netfilter/nf_tables_api.c
@@ -343,6 +343,11 @@ static void nft_trans_commit_list_add_tail(struct net *net, struct nft_trans *tr
 		    nft_set_is_anonymous(nft_trans_set(trans)))
 			list_add_tail(&trans->binding_list, &nft_net->binding_list);
 		break;
+	case NFT_MSG_NEWCHAIN:
+		if (!nft_trans_chain_update(trans) &&
+		    nft_chain_binding(nft_trans_chain(trans)))
+			list_add_tail(&trans->binding_list, &nft_net->binding_list);
+		break;
 	}
 
 	list_add_tail(&trans->list, &nft_net->commit_list);
@@ -9365,6 +9370,14 @@ static int nf_tables_commit(struct net *net, struct sk_buff *skb)
 				return -EINVAL;
 			}
 			break;
+		case NFT_MSG_NEWCHAIN:
+			if (!nft_trans_chain_update(trans) &&
+			    nft_chain_binding(nft_trans_chain(trans)) &&
+			    !nft_trans_chain_bound(trans)) {
+				pr_warn_once("nftables ruleset with unbound chain\n");
+				return -EINVAL;
+			}
+			break;
 		}
 	}
 
-- 
2.30.2