From: Pablo Neira Ayuso pablo@netfilter.org
[ Upstream commit b7b1d02fc43925a4d569ec221715db2dfa1ce4f5 ]
The internal stream state sets the timeout to 120 seconds 2 seconds after the creation of the flow, attach this internal stream state to the IPS_ASSURED flag for consistent event reporting.
Before this patch:
[NEW] udp 17 30 src=10.246.11.13 dst=216.239.35.0 sport=37282 dport=123 [UNREPLIED] src=216.239.35.0 dst=10.246.11.13 sport=123 dport=37282 [UPDATE] udp 17 30 src=10.246.11.13 dst=216.239.35.0 sport=37282 dport=123 src=216.239.35.0 dst=10.246.11.13 sport=123 dport=37282 [UPDATE] udp 17 30 src=10.246.11.13 dst=216.239.35.0 sport=37282 dport=123 src=216.239.35.0 dst=10.246.11.13 sport=123 dport=37282 [ASSURED] [DESTROY] udp 17 src=10.246.11.13 dst=216.239.35.0 sport=37282 dport=123 src=216.239.35.0 dst=10.246.11.13 sport=123 dport=37282 [ASSURED]
Note IPS_ASSURED for the flow not yet in the internal stream state.
after this update:
[NEW] udp 17 30 src=10.246.11.13 dst=216.239.35.0 sport=37282 dport=123 [UNREPLIED] src=216.239.35.0 dst=10.246.11.13 sport=123 dport=37282 [UPDATE] udp 17 30 src=10.246.11.13 dst=216.239.35.0 sport=37282 dport=123 src=216.239.35.0 dst=10.246.11.13 sport=123 dport=37282 [UPDATE] udp 17 120 src=10.246.11.13 dst=216.239.35.0 sport=37282 dport=123 src=216.239.35.0 dst=10.246.11.13 sport=123 dport=37282 [ASSURED] [DESTROY] udp 17 src=10.246.11.13 dst=216.239.35.0 sport=37282 dport=123 src=216.239.35.0 dst=10.246.11.13 sport=123 dport=37282 [ASSURED]
Before this patch, short-lived UDP flows never entered IPS_ASSURED, so they were already candidate flow to be deleted by early_drop under stress.
Before this patch, IPS_ASSURED is set on regardless the internal stream state, attach this internal stream state to IPS_ASSURED.
packet #1 (original direction) enters NEW state packet #2 (reply direction) enters ESTABLISHED state, sets on IPS_SEEN_REPLY paclet #3 (any direction) sets on IPS_ASSURED (if 2 seconds since the creation has passed by).
Reported-by: Maciej Żenczykowski zenczykowski@gmail.com Signed-off-by: Pablo Neira Ayuso pablo@netfilter.org Signed-off-by: Sasha Levin sashal@kernel.org --- net/netfilter/nf_conntrack_proto_udp.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-)
diff --git a/net/netfilter/nf_conntrack_proto_udp.c b/net/netfilter/nf_conntrack_proto_udp.c index f8e3c0d2602f6..3b516cffc779b 100644 --- a/net/netfilter/nf_conntrack_proto_udp.c +++ b/net/netfilter/nf_conntrack_proto_udp.c @@ -104,10 +104,13 @@ int nf_conntrack_udp_packet(struct nf_conn *ct, */ if (test_bit(IPS_SEEN_REPLY_BIT, &ct->status)) { unsigned long extra = timeouts[UDP_CT_UNREPLIED]; + bool stream = false;
/* Still active after two seconds? Extend timeout. */ - if (time_after(jiffies, ct->proto.udp.stream_ts)) + if (time_after(jiffies, ct->proto.udp.stream_ts)) { extra = timeouts[UDP_CT_REPLIED]; + stream = true; + }
nf_ct_refresh_acct(ct, ctinfo, skb, extra);
@@ -116,7 +119,7 @@ int nf_conntrack_udp_packet(struct nf_conn *ct, return NF_ACCEPT;
/* Also, more likely to be important, and not a probe */ - if (!test_and_set_bit(IPS_ASSURED_BIT, &ct->status)) + if (stream && !test_and_set_bit(IPS_ASSURED_BIT, &ct->status)) nf_conntrack_event_cache(IPCT_ASSURED, ct); } else { nf_ct_refresh_acct(ct, ctinfo, skb, timeouts[UDP_CT_UNREPLIED]);