netfilter: nf_tables: Fix potential data-race in __nft_obj_type_get()

mainline inclusion
from mainline-v6.9-rc5
commit d78d867dcea69c328db30df665be5be7d0148484
category: bugfix
bugzilla: https://gitee.com/src-openeuler/kernel/issues/I9L4T1
CVE: CVE-2024-27019

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=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: e5009240 ("netfilter: nf_tables: add stateful objects")
Signed-off-by: Ziyang Xuan <william.xuanziyang@huawei.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Conflicts:
	net/netfilter/nf_tables_api.c
[The version does not include 776d45164844.]
Signed-off-by: Ziyang Xuan <william.xuanziyang@huawei.com>