[PATCH nf] netfilter: nf_tables: fix ct untracked match breakage

[PATCH nf] netfilter: nf_tables: fix ct untracked match breakage

[Florian Westphal]

"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@rvf6.com>
Link: https://marc.info/?l=netfilter&m=168294996212038&w=2
Signed-off-by: Florian Westphal <fw@strlen.de>
---
 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;
-- 
2.40.1

Re: [PATCH nf] netfilter: nf_tables: fix ct untracked match breakage

[Pablo Neira Ayuso]

On Wed, May 03, 2023 at 12:00:18PM +0200, Florian Westphal wrote:
> "ct untracked" no longer works properly due to erroneous NFT_BREAK.
> We have to check ctinfo enum first.

Applied, thanks