| Message ID | 15ed198f9be877a704af51b906cf2fd655d8590b.1712472595.git.william.xuanziyang@huawei.com |
|---|---|
| State | Accepted |
| Headers | show |
| Series | netfilter: nf_tables: Use rcu lock to enhance protection of the lists | expand |
On Sun, Apr 07, 2024 at 02:56:04PM +0800, Ziyang Xuan wrote: > 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 pertential > 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. Applied to nf, thanks
diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c index 47e1a22e8fb1..646d59685cfd 100644 --- a/net/netfilter/nf_tables_api.c +++ b/net/netfilter/nf_tables_api.c @@ -3056,7 +3056,7 @@ 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; @@ -3088,9 +3088,13 @@ 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
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 pertential 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> --- net/netfilter/nf_tables_api.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-)