netdev - [PATCH net 1/1] netfilter: nf_tables: fix ct untracked match breakage

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Message-Id: <20230503201143.12310-2-pablo@netfilter.org>
Date: Wed,  3 May 2023 22:11:43 +0200
From: Pablo Neira Ayuso <pablo@...filter.org>
To: netfilter-devel@...r.kernel.org
Cc: davem@...emloft.net,
	netdev@...r.kernel.org,
	kuba@...nel.org,
	pabeni@...hat.com,
	edumazet@...gle.com
Subject: [PATCH net 1/1] netfilter: nf_tables: fix ct untracked match breakage

From: Florian Westphal <fw@...len.de>

"ct untracked" no longer works properly due to erroneous NFT_BREAK.
We have to check ctinfo enum first.

Fixes: d9e789147605 ("netfilter: nf_tables: avoid retpoline overhead for some ct expression calls")
Reported-by: Rvfg <i@...6.com>
Link: https://marc.info/?l=netfilter&m=168294996212038&w=2
Signed-off-by: Florian Westphal <fw@...len.de>
Signed-off-by: Pablo Neira Ayuso <pablo@...filter.org>
---
 net/netfilter/nft_ct_fast.c | 14 ++++++++++----
 1 file changed, 10 insertions(+), 4 deletions(-)

diff --git a/net/netfilter/nft_ct_fast.c b/net/netfilter/nft_ct_fast.c
index 89983b0613fa..e684c8a91848 100644
--- a/net/netfilter/nft_ct_fast.c
+++ b/net/netfilter/nft_ct_fast.c
@@ -15,10 +15,6 @@ void nft_ct_get_fast_eval(const struct nft_expr *expr,
 	unsigned int state;
 
 	ct = nf_ct_get(pkt->skb, &ctinfo);
-	if (!ct) {
-		regs->verdict.code = NFT_BREAK;
-		return;
-	}
 
 	switch (priv->key) {
 	case NFT_CT_STATE:
@@ -30,6 +26,16 @@ void nft_ct_get_fast_eval(const struct nft_expr *expr,
 			state = NF_CT_STATE_INVALID_BIT;
 		*dest = state;
 		return;
+	default:
+		break;
+	}
+
+	if (!ct) {
+		regs->verdict.code = NFT_BREAK;
+		return;
+	}
+
+	switch (priv->key) {
 	case NFT_CT_DIRECTION:
 		nft_reg_store8(dest, CTINFO2DIR(ctinfo));
 		return;
-- 
2.30.2