netfilter: nf_tables: reject new basechain after table flag update

jira VULN-5134
cve CVE-2024-35900
commit-author Pablo Neira Ayuso <[email protected]>
commit 994209d
upstream-diff Fixed up a couple of small conflicts introduced by
cherry picking from a very new source back into an ancient source.

When dormant flag is toggled, hooks are disabled in the commit phase by
iterating over current chains in table (existing and new).

The following configuration allows for an inconsistent state:

  add table x
  add chain x y { type filter hook input priority 0; }
  add table x { flags dormant; }
  add chain x w { type filter hook input priority 1; }

which triggers the following warning when trying to unregister chain w
which is already unregistered.

[  127.322252] WARNING: CPU: 7 PID: 1211 at net/netfilter/core.c:50                                                                     1 __nf_unregister_net_hook+0x21a/0x260
[...]
[  127.322519] Call Trace:
[  127.322521]  <TASK>
[  127.322524]  ? __warn+0x9f/0x1a0
[  127.322531]  ? __nf_unregister_net_hook+0x21a/0x260
[  127.322537]  ? report_bug+0x1b1/0x1e0
[  127.322545]  ? handle_bug+0x3c/0x70
[  127.322552]  ? exc_invalid_op+0x17/0x40
[  127.322556]  ? asm_exc_invalid_op+0x1a/0x20
[  127.322563]  ? kasan_save_free_info+0x3b/0x60
[  127.322570]  ? __nf_unregister_net_hook+0x6a/0x260
[  127.322577]  ? __nf_unregister_net_hook+0x21a/0x260
[  127.322583]  ? __nf_unregister_net_hook+0x6a/0x260
[  127.322590]  ? __nf_tables_unregister_hook+0x8a/0xe0 [nf_tables]
[  127.322655]  nft_table_disable+0x75/0xf0 [nf_tables]
[  127.322717]  nf_tables_commit+0x2571/0x2620 [nf_tables]

Fixes: 179d9ba ("netfilter: nf_tables: fix table flag updates")
	Signed-off-by: Pablo Neira Ayuso <[email protected]>
(cherry picked from commit 994209d)
	Signed-off-by: Greg Rose <[email protected]>

Conflicts:
	net/netfilter/nf_tables_api.c

net/netfilter/nf_tables_api.c

@@ -2040,6 +2040,9 @@ static int nf_tables_addchain(struct nft_ctx *ctx, u8 family, u8 genmask,
 		struct nft_stats __percpu *stats = NULL;
 		struct nft_chain_hook hook;
 
+		if (table->flags & __NFT_TABLE_F_UPDATE)
+			return -EINVAL;
+
 		err = nft_chain_parse_hook(net, nla, &hook, family, true);
 		if (err < 0)
 			return err;