From 6ac86ac74e3a0608424240cc1ce813ad6e8a73dd Mon Sep 17 00:00:00 2001 From: Florian Westphal Date: Mon, 7 Jul 2025 22:32:44 +0200 Subject: [PATCH] netfilter: nf_tables: hide clash bit from userspace Its a kernel implementation detail, at least at this time: We can later decide to revert this patch if there is a compelling reason, but then we should also remove the ifdef that prevents exposure of ip_conntrack_status enum IPS_NAT_CLASH value in the uapi header. Clash entries are not included in dumps (true for both old /proc and ctnetlink) either. So for now exclude the clash bit when dumping. Fixes: 7e5c6aa67e6f ("netfilter: nf_tables: add packets conntrack state to debug trace info") Link: https://lore.kernel.org/netfilter-devel/aGwf3dCggwBlRKKC@strlen.de/ Signed-off-by: Florian Westphal Signed-off-by: Pablo Neira Ayuso --- net/netfilter/nf_tables_trace.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/net/netfilter/nf_tables_trace.c b/net/netfilter/nf_tables_trace.c index ae3fe87195abc..a88abae5a9de2 100644 --- a/net/netfilter/nf_tables_trace.c +++ b/net/netfilter/nf_tables_trace.c @@ -127,6 +127,9 @@ static int nf_trace_fill_ct_info(struct sk_buff *nlskb, if (nla_put_be32(nlskb, NFTA_TRACE_CT_ID, (__force __be32)id)) return -1; + /* Kernel implementation detail, withhold this from userspace for now */ + status &= ~IPS_NAT_CLASH; + if (status && nla_put_be32(nlskb, NFTA_TRACE_CT_STATUS, htonl(status))) return -1; } -- 2.47.2