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authorZiyang Xuan <william.xuanziyang@huawei.com>2024-04-03 15:22:04 +0800
committerPablo Neira Ayuso <pablo@netfilter.org>2024-04-04 11:38:34 +0200
commit24225011d81b471acc0e1e315b7d9905459a6304 (patch)
tree0b727c0505617447c54a84e1ddd5836b25796ad9 /net
parent994209ddf4f430946f6247616b2e33d179243769 (diff)
netfilter: nf_tables: Fix potential data-race in __nft_flowtable_type_get()
nft_unregister_flowtable_type() within nf_flow_inet_module_exit() can concurrent with __nft_flowtable_type_get() within nf_tables_newflowtable(). And thhere is not any protection when iterate over nf_tables_flowtables list in __nft_flowtable_type_get(). Therefore, there is pertential data-race of nf_tables_flowtables list entry. Use list_for_each_entry_rcu() to iterate over nf_tables_flowtables list in __nft_flowtable_type_get(), and use rcu_read_lock() in the caller nft_flowtable_type_get() to protect the entire type query process. Fixes: 3b49e2e94e6e ("netfilter: nf_tables: add flow table netlink frontend") Signed-off-by: Ziyang Xuan <william.xuanziyang@huawei.com> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Diffstat (limited to 'net')
-rw-r--r--net/netfilter/nf_tables_api.c9
1 files changed, 7 insertions, 2 deletions
diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c
index 1eb51bf24fc2..e02d0ae4f436 100644
--- a/net/netfilter/nf_tables_api.c
+++ b/net/netfilter/nf_tables_api.c
@@ -8296,11 +8296,12 @@ static int nft_flowtable_parse_hook(const struct nft_ctx *ctx,
return err;
}
+/* call under rcu_read_lock */
static const struct nf_flowtable_type *__nft_flowtable_type_get(u8 family)
{
const struct nf_flowtable_type *type;
- list_for_each_entry(type, &nf_tables_flowtables, list) {
+ list_for_each_entry_rcu(type, &nf_tables_flowtables, list) {
if (family == type->family)
return type;
}
@@ -8312,9 +8313,13 @@ nft_flowtable_type_get(struct net *net, u8 family)
{
const struct nf_flowtable_type *type;
+ rcu_read_lock();
type = __nft_flowtable_type_get(family);
- if (type != NULL && try_module_get(type->owner))
+ if (type != NULL && try_module_get(type->owner)) {
+ rcu_read_unlock();
return type;
+ }
+ rcu_read_unlock();
lockdep_nfnl_nft_mutex_not_held();
#ifdef CONFIG_MODULES