From 8a9dc07ba92497a81f1ff65d25c2ba7b6f9a8bdc Mon Sep 17 00:00:00 2001 From: Florian Westphal Date: Mon, 3 Jul 2023 13:43:18 +0200 Subject: [PATCH] netfilter: conntrack: gre: don't set assured flag for clash entries Now that conntrack core is allowd to insert clashing entries, make sure GRE won't set assured flag on NAT_CLASH entries, just like UDP. Doing so prevents early_drop logic for these entries. Fixes: d671fd82eaa9 ("netfilter: conntrack: allow insertion clash of gre protocol") Signed-off-by: Florian Westphal Signed-off-by: Pablo Neira Ayuso --- net/netfilter/nf_conntrack_proto_gre.c | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-) diff --git a/net/netfilter/nf_conntrack_proto_gre.c b/net/netfilter/nf_conntrack_proto_gre.c index ad6f0ca40cd2..af369e686fc5 100644 --- a/net/netfilter/nf_conntrack_proto_gre.c +++ b/net/netfilter/nf_conntrack_proto_gre.c @@ -205,6 +205,8 @@ int nf_conntrack_gre_packet(struct nf_conn *ct, enum ip_conntrack_info ctinfo, const struct nf_hook_state *state) { + unsigned long status; + if (!nf_ct_is_confirmed(ct)) { unsigned int *timeouts = nf_ct_timeout_lookup(ct); @@ -217,11 +219,17 @@ int nf_conntrack_gre_packet(struct nf_conn *ct, ct->proto.gre.timeout = timeouts[GRE_CT_UNREPLIED]; } + status = READ_ONCE(ct->status); /* If we've seen traffic both ways, this is a GRE connection. * Extend timeout. */ - if (ct->status & IPS_SEEN_REPLY) { + if (status & IPS_SEEN_REPLY) { nf_ct_refresh_acct(ct, ctinfo, skb, ct->proto.gre.stream_timeout); + + /* never set ASSURED for IPS_NAT_CLASH, they time out soon */ + if (unlikely((status & IPS_NAT_CLASH))) + return NF_ACCEPT; + /* Also, more likely to be important, and not a probe. */ if (!test_and_set_bit(IPS_ASSURED_BIT, &ct->status)) nf_conntrack_event_cache(IPCT_ASSURED, ct);