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

Vulnerability Description

In the Linux kernel, the following vulnerability has been resolved: netfilter: nf_tables: Fix potential data-race in __nft_flowtable_type_get() 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.

References

• https://git.kernel.org/stable/c/69d1fe14a680042ec913f22196b58e2c8ff1b007
• https://git.kernel.org/stable/c/a347bc8e6251eaee4b619da28020641eb5b0dd77
• https://git.kernel.org/stable/c/940d41caa71f0d3a52df2fde5fada524a993e331
• https://git.kernel.org/stable/c/2485bcfe05ee3cf9ca8923a94fa2e456924c79c8
• https://git.kernel.org/stable/c/9b5b7708ec2be21dd7ef8ca0e3abe4ae9f3b083b
• https://git.kernel.org/stable/c/8b891153b2e4dc0ca9d9dab8f619d49c740813df
• https://git.kernel.org/stable/c/e684b1674fd1ca4361812a491242ae871d6b2859
• https://git.kernel.org/stable/c/24225011d81b471acc0e1e315b7d9905459a6304