From 994209ddf4f430946f6247616b2e33d179243769 Mon Sep 17 00:00:00 2001 From: Pablo Neira Ayuso Date: Mon, 1 Apr 2024 00:33:02 +0200 Subject: [PATCH] netfilter: nf_tables: reject new basechain after table flag update 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] [ 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 --- net/netfilter/nf_tables_api.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c index 17bf53cd0e848c..1eb51bf24fc2e5 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;