From 04553e40a19178f50ff56470bc72313632fb9994 Mon Sep 17 00:00:00 2001
From: Ali Abdallah <aabdallah@suse.de>
Date: Fri, 28 May 2021 12:49:24 +0200
Subject: [PATCH] netfilter: conntrack: add new sysctl to disable RST check
Git-commit: 1da4cd82dd180224503e745ccf3220e3490d8897
Patch-mainline: v5.14-rc2
References: bsc#1183947 bsc#1185950
This patch adds a new sysctl tcp_ignore_invalid_rst to disable marking
out of segments RSTs as INVALID.
Signed-off-by: Ali Abdallah <aabdallah@suse.de>
Acked-by: Ali Abdallah <aabdallah@suse.de>
---
Documentation/networking/nf_conntrack-sysctl.txt | 6 ++++++
include/net/netns/conntrack.h | 3 +++
net/netfilter/nf_conntrack_proto_tcp.c | 6 +++++-
net/netfilter/nf_conntrack_standalone.c | 10 ++++++++++
4 files changed, 24 insertions(+), 1 deletion(-)
diff --git a/Documentation/networking/nf_conntrack-sysctl.txt b/Documentation/networking/nf_conntrack-sysctl.txt
index f75c2ce6e..4d4925826 100644
--- a/Documentation/networking/nf_conntrack-sysctl.txt
+++ b/Documentation/networking/nf_conntrack-sysctl.txt
@@ -103,6 +103,12 @@ nf_conntrack_tcp_be_liberal - BOOLEAN
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.
+nf_conntrack_tcp_ignore_invalid_rst - BOOLEAN
+ - 0 - disabled (default)
+ - 1 - enabled
+
+ If it's non-zero, we don't mark out of window RST segments as INVALID.
+
nf_conntrack_tcp_loose - BOOLEAN
0 - disabled
not 0 - enabled (default)
diff --git a/include/net/netns/conntrack.h b/include/net/netns/conntrack.h
index 806454e76..cc8e97940 100644
--- a/include/net/netns/conntrack.h
+++ b/include/net/netns/conntrack.h
@@ -27,6 +27,9 @@ struct nf_tcp_net {
int tcp_loose;
int tcp_be_liberal;
int tcp_max_retrans;
+#ifndef __GENKSYMS__
+ int tcp_ignore_invalid_rst;
+#endif
};
enum udp_conntrack {
diff --git a/net/netfilter/nf_conntrack_proto_tcp.c b/net/netfilter/nf_conntrack_proto_tcp.c
index 9d825992c..35ee0fa95 100644
--- a/net/netfilter/nf_conntrack_proto_tcp.c
+++ b/net/netfilter/nf_conntrack_proto_tcp.c
@@ -36,6 +36,8 @@
If it's non-zero, we mark only out of window RST segments as INVALID. */
static int nf_ct_tcp_be_liberal __read_mostly = 0;
+static int nf_ct_tcp_ignore_invalid_rst __read_mostly = 0;
+
/* If it is set to zero, we disable picking up already established
connections. */
static int nf_ct_tcp_loose __read_mostly = 1;
@@ -1078,7 +1080,8 @@ int nf_conntrack_tcp_packet(struct nf_conn *ct,
if (seq == 0 && !nf_conntrack_tcp_established(ct))
break;
- if (before(seq, ct->proto.tcp.seen[!dir].td_maxack)) {
+ if (before(seq, ct->proto.tcp.seen[!dir].td_maxack) &&
+ !tn->tcp_ignore_invalid_rst) {
/* Invalid RST */
spin_unlock_bh(&ct->lock);
nf_ct_l4proto_log_invalid(skb, ct, "invalid rst");
@@ -1452,6 +1455,7 @@ void nf_conntrack_tcp_init_net(struct net *net)
tn->tcp_loose = nf_ct_tcp_loose;
tn->tcp_be_liberal = nf_ct_tcp_be_liberal;
tn->tcp_max_retrans = nf_ct_tcp_max_retrans;
+ tn->tcp_ignore_invalid_rst = nf_ct_tcp_ignore_invalid_rst;
}
const struct nf_conntrack_l4proto nf_conntrack_l4proto_tcp =
diff --git a/net/netfilter/nf_conntrack_standalone.c b/net/netfilter/nf_conntrack_standalone.c
index 0006503d2..638e49f57 100644
--- a/net/netfilter/nf_conntrack_standalone.c
+++ b/net/netfilter/nf_conntrack_standalone.c
@@ -565,6 +565,7 @@ enum nf_ct_sysctl_index {
NF_SYSCTL_CT_PROTO_TIMEOUT_TCP_UNACK,
NF_SYSCTL_CT_PROTO_TCP_LOOSE,
NF_SYSCTL_CT_PROTO_TCP_LIBERAL,
+ NF_SYSCTL_CT_PROTO_TCP_IGNORE_INVALID_RST,
NF_SYSCTL_CT_PROTO_TCP_MAX_RETRANS,
NF_SYSCTL_CT_PROTO_TIMEOUT_UDP,
NF_SYSCTL_CT_PROTO_TIMEOUT_UDP_STREAM,
@@ -770,6 +771,14 @@ static struct ctl_table nf_ct_sysctl_table[] = {
.extra1 = &zero,
.extra2 = &one,
},
+ [NF_SYSCTL_CT_PROTO_TCP_IGNORE_INVALID_RST] = {
+ .procname = "nf_conntrack_tcp_ignore_invalid_rst",
+ .maxlen = sizeof(int),
+ .mode = 0644,
+ .proc_handler = proc_dointvec_minmax,
+ .extra1 = &zero,
+ .extra2 = &one,
+ },
[NF_SYSCTL_CT_PROTO_TCP_MAX_RETRANS] = {
.procname = "nf_conntrack_tcp_max_retrans",
.maxlen = sizeof(unsigned int),
@@ -962,6 +971,7 @@ static void nf_conntrack_standalone_init_tcp_sysctl(struct net *net,
XASSIGN(LOOSE, &tn->tcp_loose);
XASSIGN(LIBERAL, &tn->tcp_be_liberal);
XASSIGN(MAX_RETRANS, &tn->tcp_max_retrans);
+ XASSIGN(IGNORE_INVALID_RST, &tn->tcp_ignore_invalid_rst);
#undef XASSIGN
}
--
2.26.2