[PATCH 5.10 318/509] netfilter: nf_tables: reject unbound chain set before commit phase

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

From: Pablo Neira Ayuso <pablo@netfilter.org>

[ Upstream commit 62e1e94b246e685d89c3163aaef4b160e42ceb02 ]

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.

Fixes: d0e2c7de92c7 ("netfilter: nf_tables: add NFT_CHAIN_BINDING")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 net/netfilter/nf_tables_api.c |   13 +++++++++++++
 1 file changed, 13 insertions(+)

--- a/net/netfilter/nf_tables_api.c
+++ b/net/netfilter/nf_tables_api.c
@@ -360,6 +360,11 @@ static void nft_trans_commit_list_add_ta
 		if (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);
@@ -8043,6 +8048,14 @@ static int nf_tables_commit(struct net *
 				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;
 		}
 	}