Merge tag 'nf-24-03-28' of git://git.kernel.org/pub/scm/linux/kernel/…

…git/netfilter/nf

Pablo Neira Ayuso says:

====================
Netfilter fixes for net

The following patchset contains Netfilter fixes for net:

Patch #1 reject destroy chain command to delete device hooks in netdev
         family, hence, only delchain commands are allowed.

Patch #2 reject table flag update interference with netdev basechain
	 hook updates, this can leave hooks in inconsistent
	 registration/unregistration state.

Patch #3 do not unregister netdev basechain hooks if table is dormant.
	 Otherwise, splat with double unregistration is possible.

Patch #4 fixes Kconfig to allow to restore IP_NF_ARPTABLES,
	 from Kuniyuki Iwashima.

There are a more fixes still in progress on my side that need more work.

* tag 'nf-24-03-28' of git://git.kernel.org/pub/scm/linux/kernel/git/netfilter/nf:
  netfilter: arptables: Select NETFILTER_FAMILY_ARP when building arp_tables.c
  netfilter: nf_tables: skip netdev hook unregistration if table is dormant
  netfilter: nf_tables: reject table flag and netdev basechain updates
  netfilter: nf_tables: reject destroy command to remove basechain hooks
====================

Link: https://lore.kernel.org/r/20240328031855.2063-1-pablo@netfilter.org
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

net/ipv4/netfilter/Kconfig

@@ -329,6 +329,7 @@ config NFT_COMPAT_ARP
 config IP_NF_ARPFILTER
 	tristate "arptables-legacy packet filtering support"
 	select IP_NF_ARPTABLES
+	select NETFILTER_FAMILY_ARP
 	depends on NETFILTER_XTABLES
 	help
 	  ARP packet filtering defines a table `filter', which has a series of

net/netfilter/nf_tables_api.c

@@ -1200,6 +1200,25 @@ static void nf_tables_table_disable(struct net *net, struct nft_table *table)
 					 __NFT_TABLE_F_WAS_AWAKEN | \
 					 __NFT_TABLE_F_WAS_ORPHAN)
 
+static bool nft_table_pending_update(const struct nft_ctx *ctx)
+{
+	struct nftables_pernet *nft_net = nft_pernet(ctx->net);
+	struct nft_trans *trans;
+
+	if (ctx->table->flags & __NFT_TABLE_F_UPDATE)
+		return true;
+
+	list_for_each_entry(trans, &nft_net->commit_list, list) {
+		if ((trans->msg_type == NFT_MSG_NEWCHAIN ||
+		     trans->msg_type == NFT_MSG_DELCHAIN) &&
+		    trans->ctx.table == ctx->table &&
+		    nft_trans_chain_update(trans))
+			return true;
+	}
+
+	return false;
+}
+
 static int nf_tables_updtable(struct nft_ctx *ctx)
 {
 	struct nft_trans *trans;
@@ -1226,7 +1245,7 @@ static int nf_tables_updtable(struct nft_ctx *ctx)
 		return -EOPNOTSUPP;
 
 	/* No dormant off/on/off/on games in single transaction */
-	if (ctx->table->flags & __NFT_TABLE_F_UPDATE)
+	if (nft_table_pending_update(ctx))
 		return -EINVAL;
 
 	trans = nft_trans_alloc(ctx, NFT_MSG_NEWTABLE,
@@ -2631,6 +2650,13 @@ static int nf_tables_updchain(struct nft_ctx *ctx, u8 genmask, u8 policy,
 		}
 	}
 
+	if (table->flags & __NFT_TABLE_F_UPDATE &&
+	    !list_empty(&hook.list)) {
+		NL_SET_BAD_ATTR(extack, attr);
+		err = -EOPNOTSUPP;
+		goto err_hooks;
+	}
+
 	if (!(table->flags & NFT_TABLE_F_DORMANT) &&
 	    nft_is_base_chain(chain) &&
 	    !list_empty(&hook.list)) {
@@ -2860,6 +2886,9 @@ static int nft_delchain_hook(struct nft_ctx *ctx,
 	struct nft_trans *trans;
 	int err;
 
+	if (ctx->table->flags & __NFT_TABLE_F_UPDATE)
+		return -EOPNOTSUPP;
+
 	err = nft_chain_parse_hook(ctx->net, basechain, nla, &chain_hook,
 				   ctx->family, chain->flags, extack);
 	if (err < 0)
@@ -2944,7 +2973,8 @@ static int nf_tables_delchain(struct sk_buff *skb, const struct nfnl_info *info,
 	nft_ctx_init(&ctx, net, skb, info->nlh, family, table, chain, nla);
 
 	if (nla[NFTA_CHAIN_HOOK]) {
-		if (chain->flags & NFT_CHAIN_HW_OFFLOAD)
+		if (NFNL_MSG_TYPE(info->nlh->nlmsg_type) == NFT_MSG_DESTROYCHAIN ||
+		    chain->flags & NFT_CHAIN_HW_OFFLOAD)
 			return -EOPNOTSUPP;
 
 		if (nft_is_base_chain(chain)) {
@@ -10182,9 +10212,11 @@ static int nf_tables_commit(struct net *net, struct sk_buff *skb)
 			if (nft_trans_chain_update(trans)) {
 				nf_tables_chain_notify(&trans->ctx, NFT_MSG_DELCHAIN,
 						       &nft_trans_chain_hooks(trans));
-				nft_netdev_unregister_hooks(net,
-							    &nft_trans_chain_hooks(trans),
-							    true);
+				if (!(trans->ctx.table->flags & NFT_TABLE_F_DORMANT)) {
+					nft_netdev_unregister_hooks(net,
+								    &nft_trans_chain_hooks(trans),
+								    true);
+				}
 			} else {
 				nft_chain_del(trans->ctx.chain);
 				nf_tables_chain_notify(&trans->ctx, NFT_MSG_DELCHAIN,
@@ -10460,9 +10492,11 @@ static int __nf_tables_abort(struct net *net, enum nfnl_abort_action action)
 			break;
 		case NFT_MSG_NEWCHAIN:
 			if (nft_trans_chain_update(trans)) {
-				nft_netdev_unregister_hooks(net,
-							    &nft_trans_chain_hooks(trans),
-							    true);
+				if (!(trans->ctx.table->flags & NFT_TABLE_F_DORMANT)) {
+					nft_netdev_unregister_hooks(net,
+								    &nft_trans_chain_hooks(trans),
+								    true);
+				}
 				free_percpu(nft_trans_chain_stats(trans));
 				kfree(nft_trans_chain_name(trans));
 				nft_trans_destroy(trans);