stable inclusion from stable-v4.19.312 commit 69d1fe14a680042ec913f22196b58e2c8ff1b007 category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/I9QG2A CVE: CVE-2024-35898 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=... -------------------------------- commit 24225011d81b471acc0e1e315b7d9905459a6304 upstream. 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> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Ziyang Xuan <william.xuanziyang@huawei.com> --- net/netfilter/nf_tables_api.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c index fb50b028043d..97e56cadb4bf 100644 --- a/net/netfilter/nf_tables_api.c +++ b/net/netfilter/nf_tables_api.c @@ -5628,11 +5628,12 @@ static int nf_tables_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; } @@ -5644,9 +5645,13 @@ 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 -- 2.25.1