diff mbox series

[nf,v2,4/4] netfilter: nf_tables: reject new basechain after table flag update

Message ID 20240403111832.234325-4-pablo@netfilter.org
State Accepted
Headers show
Series [nf,v2,1/4] netfilter: nf_tables: release batch on table validation from abort path | expand

Commit Message

Pablo Neira Ayuso April 3, 2024, 11:18 a.m. UTC
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: 179d9ba5559a ("netfilter: nf_tables: fix table flag updates")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
---
v2: new in this series

 net/netfilter/nf_tables_api.c | 3 +++
 1 file changed, 3 insertions(+)
diff mbox series

Patch

diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c
index 17bf53cd0e84..1eb51bf24fc2 100644
--- a/net/netfilter/nf_tables_api.c
+++ b/net/netfilter/nf_tables_api.c
@@ -2449,6 +2449,9 @@  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;
+
 		if (flags & NFT_CHAIN_BINDING)
 			return -EOPNOTSUPP;