From 9d45a899adca041a342abce3e100d342ceb6636a Mon Sep 17 00:00:00 2001 From: ACwifidude Date: Thu, 6 Apr 2023 08:49:14 -0500 Subject: [PATCH] Revert "kernel: remove obsolete netfilter tcp window size check bypass patch" This reverts commit 75e78bcaab847557ce1782eb2dea9dff9a029171. --- ...-netfilter_optional_tcp_window_check.patch | 73 ++++++++++++++++ ...-netfilter_optional_tcp_window_check.patch | 83 +++++++++++++++++++ 2 files changed, 156 insertions(+) create mode 100644 target/linux/generic/pending-5.10/613-netfilter_optional_tcp_window_check.patch create mode 100644 target/linux/generic/pending-5.15/613-netfilter_optional_tcp_window_check.patch diff --git a/target/linux/generic/pending-5.10/613-netfilter_optional_tcp_window_check.patch b/target/linux/generic/pending-5.10/613-netfilter_optional_tcp_window_check.patch new file mode 100644 index 0000000000..79fd2762b3 --- /dev/null +++ b/target/linux/generic/pending-5.10/613-netfilter_optional_tcp_window_check.patch @@ -0,0 +1,73 @@ +From: Felix Fietkau +Subject: netfilter: optional tcp window check + +Signed-off-by: Felix Fietkau +--- + 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 + #include + ++/* 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 + #include + ++/* 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, ++ }, + {} + }; + diff --git a/target/linux/generic/pending-5.15/613-netfilter_optional_tcp_window_check.patch b/target/linux/generic/pending-5.15/613-netfilter_optional_tcp_window_check.patch new file mode 100644 index 0000000000..cb3b63cdb1 --- /dev/null +++ b/target/linux/generic/pending-5.15/613-netfilter_optional_tcp_window_check.patch @@ -0,0 +1,83 @@ +From: Felix Fietkau +Subject: netfilter: optional tcp window check + +Signed-off-by: Felix Fietkau +Signed-off-by: Christian 'Ansuel' Marangi +--- + 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)