[PATCH nf 1/3] netfilter: nf_tables: reject destroy command to remove basechain hooks

[PATCH nf 1/3] netfilter: nf_tables: reject destroy command to remove basechain hooks

[Pablo Neira Ayuso]

Report EOPNOTSUPP if NFT_MSG_DESTROYCHAIN is used to delete hooks in an
existing netdev basechain, thus, only NFT_MSG_DELCHAIN is allowed.

Fixes: 7d937b107108f ("netfilter: nf_tables: support for deleting devices in an existing netdev chain")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
---
 net/netfilter/nf_tables_api.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c
index 5fa3d3540c93..a1a8030e16a5 100644
--- a/net/netfilter/nf_tables_api.c
+++ b/net/netfilter/nf_tables_api.c
@@ -2944,7 +2944,8 @@ 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)) {
-- 
2.30.2

[PATCH nf 2/3] netfilter: nf_tables: reject table flag and netdev basechain updates

[Pablo Neira Ayuso]

netdev basechain updates are stored in the transaction object hook list.
Meanwhile, updates in the table dormant flags iterate over the existing
hooks in the basechain, thus, skipping the hooks that are being
added/deleted in this transaction, which leaves hook registration in
inconsistent state.

Reject table flag updates in combination with netdev basechain updates
in the same batch:

- Update table flags and add/delete basechain: Check from basechain update
  path if there are pending flags updates for this table.
- add/delete basechain and update table flags: Iterate over the transaction
  list to search for basechain updates from the table update path.

In both cases, the batch is rejected. Based on suggestion from Florian Westphal.

Fixes: b9703ed44ffb ("netfilter: nf_tables: support for adding new devices to an existing netdev chain")
Fixes: 7d937b107108f ("netfilter: nf_tables: support for deleting devices in an existing netdev chain")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
---
 net/netfilter/nf_tables_api.c | 31 ++++++++++++++++++++++++++++++-
 1 file changed, 30 insertions(+), 1 deletion(-)

diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c
index a1a8030e16a5..086d85fffeb1 100644
--- a/net/netfilter/nf_tables_api.c
+++ b/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)
-- 
2.30.2

[PATCH nf 3/3] netfilter: nf_tables: skip netdev hook unregistration if table is dormant

[Pablo Neira Ayuso]

Skip hook unregistration when adding or deleting devices from an
existing netdev basechain. Otherwise, commit/abort path try to
unregister hooks which not enabled.

Fixes: b9703ed44ffb ("netfilter: nf_tables: support for adding new devices to an existing netdev chain")
Fixes: 7d937b107108 ("netfilter: nf_tables: support for deleting devices in an existing netdev chain")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
---
 net/netfilter/nf_tables_api.c | 16 ++++++++++------
 1 file changed, 10 insertions(+), 6 deletions(-)

diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c
index 086d85fffeb1..fd86f2720c9e 100644
--- a/net/netfilter/nf_tables_api.c
+++ b/net/netfilter/nf_tables_api.c
@@ -10212,9 +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,
@@ -10490,9 +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);
-- 
2.30.2