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() with rcu_read_lock() to Iterate over
nf_tables_flowtables list in __nft_flowtable_type_get() to resolve it.
Signed-off-by: Ziyang Xuan <william.xuanziyang@xxxxxxxxxx>
---
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 fd86f2720c9e..fbf38e32f11d 100644
--- a/net/netfilter/nf_tables_api.c
+++ b/net/netfilter/nf_tables_api.c
@@ -8297,10 +8297,14 @@ 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) {
- if (family == type->family)
+ rcu_read_lock()
+ list_for_each_entry_rcu(type, &nf_tables_flowtables, list) {
+ if (family == type->family) {
+ rcu_read_unlock();
return type;
+ }
}
+ rcu_read_unlock();
return NULL;
}
--
2.25.1
