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kernel: remove obsolete netfilter tcp window size check bypass patch

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On any currently supported hardware, the performance impact should not
matter anymore.

Signed-off-by: Felix Fietkau <nbd@nbd.name>
This commit is contained in:
Felix Fietkau 2023-03-30 14:14:11 +02:00
parent d54c91bd9a
commit 75e78bcaab
2 changed files with 0 additions and 156 deletions
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73
target/linux/generic/pending-5.10/613-netfilter_optional_tcp_window_check.patch
View File

@ -1,73 +0,0 @@
From: Felix Fietkau <nbd@nbd.name>
Subject: netfilter: optional tcp window check
Signed-off-by: Felix Fietkau <nbd@nbd.name>
---
net/netfilter/nf_conntrack_proto_tcp.c | 13 +++++++++++++
1 file changed, 13 insertions(+)
--- a/net/netfilter/nf_conntrack_proto_tcp.c
+++ b/net/netfilter/nf_conntrack_proto_tcp.c
@@ -31,6 +31,9 @@
#include <net/netfilter/ipv4/nf_conntrack_ipv4.h>
#include <net/netfilter/ipv6/nf_conntrack_ipv6.h>
+/* Do not check the TCP window for incoming packets */
+static int nf_ct_tcp_no_window_check __read_mostly = 1;
+
/* "Be conservative in what you do,
be liberal in what you accept from others."
If it's non-zero, we mark only out of window RST segments as INVALID. */
@@ -476,6 +479,9 @@ static bool tcp_in_window(const struct n
s32 receiver_offset;
bool res, in_recv_win;
+ if (nf_ct_tcp_no_window_check)
+ return true;
+
/*
* Get the required data from the packet.
*/
@@ -1139,7 +1145,7 @@ int nf_conntrack_tcp_packet(struct nf_co
IP_CT_TCP_FLAG_DATA_UNACKNOWLEDGED &&
timeouts[new_state] > timeouts[TCP_CONNTRACK_UNACK])
timeout = timeouts[TCP_CONNTRACK_UNACK];
- else if (ct->proto.tcp.last_win == 0 &&
+ else if (!nf_ct_tcp_no_window_check && ct->proto.tcp.last_win == 0 &&
timeouts[new_state] > timeouts[TCP_CONNTRACK_RETRANS])
timeout = timeouts[TCP_CONNTRACK_RETRANS];
else
--- a/net/netfilter/nf_conntrack_standalone.c
+++ b/net/netfilter/nf_conntrack_standalone.c
@@ -25,6 +25,9 @@
#include <net/netfilter/nf_conntrack_timestamp.h>
#include <linux/rculist_nulls.h>
+/* Do not check the TCP window for incoming packets */
+static int nf_ct_tcp_no_window_check __read_mostly = 1;
+
static bool enable_hooks __read_mostly;
MODULE_PARM_DESC(enable_hooks, "Always enable conntrack hooks");
module_param(enable_hooks, bool, 0000);
@@ -657,6 +660,7 @@ enum nf_ct_sysctl_index {
NF_SYSCTL_CT_PROTO_TIMEOUT_GRE_STREAM,
#endif
+ NF_SYSCTL_CT_PROTO_TCP_NO_WINDOW_CHECK,
__NF_SYSCTL_CT_LAST_SYSCTL,
};
@@ -993,6 +997,13 @@ static struct ctl_table nf_ct_sysctl_tab
.proc_handler = proc_dointvec_jiffies,
},
#endif
+ [NF_SYSCTL_CT_PROTO_TCP_NO_WINDOW_CHECK] = {
+ .procname = "nf_conntrack_tcp_no_window_check",
+ .data = &nf_ct_tcp_no_window_check,
+ .maxlen = sizeof(unsigned int),
+ .mode = 0644,
+ .proc_handler = proc_dointvec,
+ },
{}
};

83
target/linux/generic/pending-5.15/613-netfilter_optional_tcp_window_check.patch
View File

@ -1,83 +0,0 @@
From: Felix Fietkau <nbd@nbd.name>
Subject: netfilter: optional tcp window check
Signed-off-by: Felix Fietkau <nbd@nbd.name>
Signed-off-by: Christian 'Ansuel' Marangi <ansuelsmth@gmail.com>
---
net/netfilter/nf_conntrack_proto_tcp.c | 13 +++++++++++++
1 file changed, 13 insertions(+)
--- a/net/netfilter/nf_conntrack_proto_tcp.c
+++ b/net/netfilter/nf_conntrack_proto_tcp.c
@@ -465,6 +465,9 @@ static bool tcp_in_window(struct nf_conn
s32 receiver_offset;
bool res, in_recv_win;
+ if (tn->tcp_no_window_check)
+ return true;
+
/*
* Get the required data from the packet.
*/
@@ -1191,7 +1194,7 @@ int nf_conntrack_tcp_packet(struct nf_co
IP_CT_TCP_FLAG_DATA_UNACKNOWLEDGED &&
timeouts[new_state] > timeouts[TCP_CONNTRACK_UNACK])
timeout = timeouts[TCP_CONNTRACK_UNACK];
- else if (ct->proto.tcp.last_win == 0 &&
+ else if (!tn->tcp_no_window_check && ct->proto.tcp.last_win == 0 &&
timeouts[new_state] > timeouts[TCP_CONNTRACK_RETRANS])
timeout = timeouts[TCP_CONNTRACK_RETRANS];
else
@@ -1507,6 +1510,9 @@ void nf_conntrack_tcp_init_net(struct ne
*/
tn->tcp_be_liberal = 0;
+ /* Skip Windows Check */
+ tn->tcp_no_window_check = 0;
+
/* If it's non-zero, we turn off RST sequence number check */
tn->tcp_ignore_invalid_rst = 0;
--- a/net/netfilter/nf_conntrack_standalone.c
+++ b/net/netfilter/nf_conntrack_standalone.c
@@ -633,6 +633,7 @@ enum nf_ct_sysctl_index {
#endif
NF_SYSCTL_CT_PROTO_TCP_LOOSE,
NF_SYSCTL_CT_PROTO_TCP_LIBERAL,
+ NF_SYSCTL_CT_PROTO_TCP_NO_WINDOW_CHECK,
NF_SYSCTL_CT_PROTO_TCP_IGNORE_INVALID_RST,
NF_SYSCTL_CT_PROTO_TCP_MAX_RETRANS,
NF_SYSCTL_CT_PROTO_TIMEOUT_UDP,
@@ -848,6 +849,14 @@ static struct ctl_table nf_ct_sysctl_tab
.extra1 = SYSCTL_ZERO,
.extra2 = SYSCTL_ONE,
},
+ [NF_SYSCTL_CT_PROTO_TCP_NO_WINDOW_CHECK] = {
+ .procname = "nf_conntrack_tcp_no_window_check",
+ .maxlen = sizeof(u8),
+ .mode = 0644,
+ .proc_handler = proc_dou8vec_minmax,
+ .extra1 = SYSCTL_ZERO,
+ .extra2 = SYSCTL_ONE,
+ },
[NF_SYSCTL_CT_PROTO_TCP_IGNORE_INVALID_RST] = {
.procname = "nf_conntrack_tcp_ignore_invalid_rst",
.maxlen = sizeof(u8),
@@ -1058,6 +1067,7 @@ static void nf_conntrack_standalone_init
XASSIGN(LOOSE, &tn->tcp_loose);
XASSIGN(LIBERAL, &tn->tcp_be_liberal);
+ XASSIGN(NO_WINDOW_CHECK, &tn->tcp_no_window_check);
XASSIGN(MAX_RETRANS, &tn->tcp_max_retrans);
XASSIGN(IGNORE_INVALID_RST, &tn->tcp_ignore_invalid_rst);
#undef XASSIGN
--- a/include/net/netns/conntrack.h
+++ b/include/net/netns/conntrack.h
@@ -26,6 +26,7 @@ struct nf_tcp_net {
unsigned int timeouts[TCP_CONNTRACK_TIMEOUT_MAX];
u8 tcp_loose;
u8 tcp_be_liberal;
+ u8 tcp_no_window_check;
u8 tcp_max_retrans;
u8 tcp_ignore_invalid_rst;
#if IS_ENABLED(CONFIG_NF_FLOW_TABLE)