netfilter: nf_tables: skip bound chain on rule flush

jira VULN-8826
cve CVE-2023-3777
commit-author Pablo Neira Ayuso <[email protected]>
commit 6eaf41e

Skip bound chain when flushing table rules, the rule that owns this
chain releases these objects.

Otherwise, the following warning is triggered:

  WARNING: CPU: 2 PID: 1217 at net/netfilter/nf_tables_api.c:2013 nf_tables_chain_destroy+0x1f7/0x210 [nf_tables]
  CPU: 2 PID: 1217 Comm: chain-flush Not tainted 6.1.39 #1
  RIP: 0010:nf_tables_chain_destroy+0x1f7/0x210 [nf_tables]

Fixes: d0e2c7d ("netfilter: nf_tables: add NFT_CHAIN_BINDING")
	Reported-by: Kevin Rich <[email protected]>
	Signed-off-by: Pablo Neira Ayuso <[email protected]>
	Signed-off-by: Florian Westphal <[email protected]>
(cherry picked from commit 6eaf41e)
	Signed-off-by: Anmol Jain <[email protected]>

Author: jainanmol84

net/netfilter/nf_tables_api.c

@@ -3729,6 +3729,8 @@ static int nf_tables_delrule(struct sk_buff *skb, const struct nfnl_info *info,
 		list_for_each_entry(chain, &table->chains, list) {
 			if (!nft_is_active_next(net, chain))
 				continue;
+			if (nft_chain_is_bound(chain))
+				continue;
 
 			ctx.chain = chain;
 			err = nft_delrule_by_chain(&ctx);