CVE-2022-48643

netfilter: nf_tables: fix nft_counters_enabled underflow at nf_tables_addchain()

In the Linux kernel, the following vulnerability has been resolved: netfilter: nf_tables: fix nft_counters_enabled underflow at nf_tables_addchain() syzbot is reporting underflow of nft_counters_enabled counter at nf_tables_addchain() [1], for commit 43eb8949cfdffa76 ("netfilter: nf_tables: do not leave chain stats enabled on error") missed that nf_tables_chain_destroy() after nft_basechain_init() in the error path of nf_tables_addchain() decrements the counter because nft_basechain_init() makes nft_is_base_chain() return true by setting NFT_CHAIN_BASE flag. Increment the counter immediately after returning from nft_basechain_init().