[PATCH -stable,5.10 06/10] netfilter: nf_tables: reject unbound anonymous set before commit phase

Pablo Neira Ayuso
2023-07-05T14:25:47Z

[ 938154b93be8cd611ddfd7bafc1849f3c4355201 ]

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>
---
include/net/netfilter/nf_tables.h | 3 +++
net/netfilter/nf_tables_api.c | 34 ++++++++++++++++++++++++++++---
2 files changed, 34 insertions(+), 3 deletions(-)

diff --git a/include/net/netfilter/nf_tables.h b/include/net/netfilter/nf_tables.h
index 03886052491e..716a974a7263 100644
--- a/include/net/netfilter/nf_tables.h
+++ b/include/net/netfilter/nf_tables.h
@@ -1426,6 +1426,7 @@ static inline void nft_set_elem_clear_busy(struct nft_set_ext *ext)
* struct nft_trans - nf_tables object update in transaction
*
* @list: used internally
+ * @binding_list: list of objects with possible bindings
* @msg_type: message type
* @put_net: ctx->net needs to be put
* @ctx: transaction context
@@ -1433,6 +1434,7 @@ static inline void nft_set_elem_clear_busy(struct nft_set_ext *ext)
*/
struct nft_trans {
struct list_head list;
+ struct list_head binding_list;
int msg_type;
bool put_net;
struct nft_ctx ctx;
@@ -1559,6 +1561,7 @@ __be64 nf_jiffies64_to_msecs(u64 input);
struct nftables_pernet {
struct list_head tables;
struct list_head commit_list;
+ struct list_head binding_list;
struct list_head module_list;
struct list_head notify_list;
struct mutex commit_mutex;
diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c
index c646537efaf5..ff65de8119c3 100644
--- a/net/netfilter/nf_tables_api.c
+++ b/net/netfilter/nf_tables_api.c
@@ -155,6 +155,7 @@ 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;

@@ -167,9 +168,15 @@ 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);
}

@@ -347,6 +354,14 @@ static void nft_trans_commit_list_add_tail(struct net *net, struct nft_trans *tr
struct nftables_pernet *nft_net;

nft_net = net_generic(net, nf_tables_net_id);
+
+ switch (trans->msg_type) {
+ case NFT_MSG_NEWSET:
+ if (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);
}

@@ -7717,7 +7732,7 @@ 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);
}
}
@@ -8019,6 +8034,18 @@ 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_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;
@@ -8421,7 +8448,7 @@ 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);
}

@@ -9120,6 +9147,7 @@ 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);
--
2.30.2