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

Vulnerability Description

In the Linux kernel, the following vulnerability has been resolved: 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.

References

• https://git.kernel.org/stable/c/939109c0a8e2a006a6cc8209e262d25065f4403a
• https://git.kernel.org/stable/c/b38a133d37fa421c8447b383d788c9cc6f5cb34c
• https://git.kernel.org/stable/c/934e66e231cff2b18faa2c8aad0b8cec13957e05
• https://git.kernel.org/stable/c/0b6de00206adbbfc6373b3ae38d2a6f197987907
• https://git.kernel.org/stable/c/8d56bad42ac4c43c6c72ddd6a654a2628bf839c5
• https://git.kernel.org/stable/c/a9ebf340d123ae12582210407f879d6a5a1bc25b
• https://git.kernel.org/stable/c/01f1a678b05ade4b1248019c2dcca773aebbeb7f
• https://git.kernel.org/stable/c/f969eb84ce482331a991079ab7a5c4dc3b7f89bf