From: Ali Abdallah <ali.abdallah@xxxxxxxx>
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@xxxxxxx>
Acked-by: Florian Westphal <fw@xxxxxxxxx>
Signed-off-by: Pablo Neira Ayuso <pablo@xxxxxxxxxxxxx>
---
Documentation/networking/nf_conntrack-sysctl.rst | 6 ++++++
include/net/netns/conntrack.h | 1 +
net/netfilter/nf_conntrack_proto_tcp.c | 6 +++++-
net/netfilter/nf_conntrack_standalone.c | 10 ++++++++++
4 files changed, 22 insertions(+), 1 deletion(-)
diff --git a/Documentation/networking/nf_conntrack-sysctl.rst b/Documentation/networking/nf_conntrack-sysctl.rst
index 0467b30e4abe..d31ed6c1cb0d 100644
--- a/Documentation/networking/nf_conntrack-sysctl.rst
+++ b/Documentation/networking/nf_conntrack-sysctl.rst
@@ -110,6 +110,12 @@ 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 1, 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 c3094b83a525..37e5300c7e5a 100644
--- a/include/net/netns/conntrack.h
+++ b/include/net/netns/conntrack.h
@@ -27,6 +27,7 @@ struct nf_tcp_net {
u8 tcp_loose;
u8 tcp_be_liberal;
u8 tcp_max_retrans;
+ u8 tcp_ignore_invalid_rst;
#if IS_ENABLED(CONFIG_NF_FLOW_TABLE)
unsigned int offload_timeout;
unsigned int offload_pickup;
diff --git a/net/netfilter/nf_conntrack_proto_tcp.c b/net/netfilter/nf_conntrack_proto_tcp.c
index b8ff67671e93..3259416f2ea4 100644
--- a/net/netfilter/nf_conntrack_proto_tcp.c
+++ b/net/netfilter/nf_conntrack_proto_tcp.c
@@ -1068,7 +1068,8 @@ 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, state, "invalid rst");
@@ -1466,6 +1467,9 @@ void nf_conntrack_tcp_init_net(struct net *net)
*/
tn->tcp_be_liberal = 0;
+ /* If it's non-zero, we turn off RST sequence number check */
+ tn->tcp_ignore_invalid_rst = 0;
+
/* Max number of the retransmitted packets without receiving an (acceptable)
* ACK from the destination. If this number is reached, a shorter timer
* will be started.
diff --git a/net/netfilter/nf_conntrack_standalone.c b/net/netfilter/nf_conntrack_standalone.c
index f57a951c9b5e..214d9f9e499b 100644
--- a/net/netfilter/nf_conntrack_standalone.c
+++ b/net/netfilter/nf_conntrack_standalone.c
@@ -579,6 +579,7 @@ enum nf_ct_sysctl_index {
#endif
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,
@@ -798,6 +799,14 @@ static struct ctl_table nf_ct_sysctl_table[] = {
.extra1 = SYSCTL_ZERO,
.extra2 = SYSCTL_ONE,
},
+ [NF_SYSCTL_CT_PROTO_TCP_IGNORE_INVALID_RST] = {
+ .procname = "nf_conntrack_tcp_ignore_invalid_rst",
+ .maxlen = sizeof(u8),
+ .mode = 0644,
+ .proc_handler = proc_dou8vec_minmax,
+ .extra1 = SYSCTL_ZERO,
+ .extra2 = SYSCTL_ONE,
+ },
[NF_SYSCTL_CT_PROTO_TCP_MAX_RETRANS] = {
.procname = "nf_conntrack_tcp_max_retrans",
.maxlen = sizeof(u8),
@@ -1004,6 +1013,7 @@ 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
#if IS_ENABLED(CONFIG_NF_FLOW_TABLE)
--
2.20.1
