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authorZiyang Xuan <william.xuanziyang@huawei.com>2024-04-07 14:56:04 +0800
committerPablo Neira Ayuso <pablo@netfilter.org>2024-04-11 12:08:34 +0200
commitf969eb84ce482331a991079ab7a5c4dc3b7f89bf (patch)
tree69f7a9d0a380a20ee5c08c2c09effd1b57330577 /net
parent19fa4f2a85d777a8052e869c1b892a2f7556569d (diff)
netfilter: nf_tables: Fix potential data-race in __nft_expr_type_get()
nft_unregister_expr() can concurrent with __nft_expr_type_get(), and there is not any protection when iterate over nf_tables_expressions list in __nft_expr_type_get(). Therefore, there is potential data-race of nf_tables_expressions list entry. Use list_for_each_entry_rcu() to iterate over nf_tables_expressions list in __nft_expr_type_get(), and use rcu_read_lock() in the caller nft_expr_type_get() to protect the entire type query process. Fixes: ef1f7df9170d ("netfilter: nf_tables: expression ops overloading") 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.c8
1 files changed, 6 insertions, 2 deletions
diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c
index d89d77946719..53b8c00863ad 100644
--- a/net/netfilter/nf_tables_api.c
+++ b/net/netfilter/nf_tables_api.c
@@ -3060,7 +3060,7 @@ static const struct nft_expr_type *__nft_expr_type_get(u8 family,
{
const struct nft_expr_type *type, *candidate = NULL;
- list_for_each_entry(type, &nf_tables_expressions, list) {
+ list_for_each_entry_rcu(type, &nf_tables_expressions, list) {
if (!nla_strcmp(nla, type->name)) {
if (!type->family && !candidate)
candidate = type;
@@ -3092,9 +3092,13 @@ static const struct nft_expr_type *nft_expr_type_get(struct net *net,
if (nla == NULL)
return ERR_PTR(-EINVAL);
+ rcu_read_lock();
type = __nft_expr_type_get(family, nla);
- 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