From: Ziyang Xuan william.xuanziyang@huawei.com
[ upstream commit d78d867dcea69c328db30df665be5be7d0148484 ]
nft_unregister_obj() can concurrent with __nft_obj_type_get(), and there is not any protection when iterate over nf_tables_objects list in __nft_obj_type_get(). Therefore, there is potential data-race of nf_tables_objects list entry.
Use list_for_each_entry_rcu() to iterate over nf_tables_objects list in __nft_obj_type_get(), and use rcu_read_lock() in the caller nft_obj_type_get() to protect the entire type query process.
Fixes: e50092404c1b ("netfilter: nf_tables: add stateful objects") Signed-off-by: Ziyang Xuan william.xuanziyang@huawei.com Signed-off-by: Pablo Neira Ayuso pablo@netfilter.org Signed-off-by: Kuntal Nayak kuntal.nayak@broadcom.com --- net/netfilter/nf_tables_api.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-)
diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c index de56f25dc..f3cb5c920 100644 --- a/net/netfilter/nf_tables_api.c +++ b/net/netfilter/nf_tables_api.c @@ -6238,7 +6238,7 @@ static const struct nft_object_type *__nft_obj_type_get(u32 objtype, u8 family) { const struct nft_object_type *type;
- list_for_each_entry(type, &nf_tables_objects, list) { + list_for_each_entry_rcu(type, &nf_tables_objects, list) { if (type->family != NFPROTO_UNSPEC && type->family != family) continue; @@ -6254,9 +6254,13 @@ nft_obj_type_get(struct net *net, u32 objtype, u8 family) { const struct nft_object_type *type;
+ rcu_read_lock(); type = __nft_obj_type_get(objtype, 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