target/linux/generic/pending-5.15/613-netfilter_optional_tcp_window_check.patch

   1 From: Felix Fietkau <nbd@nbd.name>
   2 Subject: netfilter: optional tcp window check
   3
   4 Signed-off-by: Felix Fietkau <nbd@nbd.name>
   5 Signed-off-by: Christian 'Ansuel' Marangi <ansuelsmth@gmail.com>
   6 ---
   7  net/netfilter/nf_conntrack_proto_tcp.c | 13 +++++++++++++
   8  1 file changed, 13 insertions(+)
   9
  10 --- a/net/netfilter/nf_conntrack_proto_tcp.c
  11 +++ b/net/netfilter/nf_conntrack_proto_tcp.c
  12 @@ -465,6 +465,9 @@ static bool tcp_in_window(struct nf_conn
  13         s32 receiver_offset;
  14         bool res, in_recv_win;
  15
  16 +       if (tn->tcp_no_window_check)
  17 +               return true;
  18 +
  19         /*
  20          * Get the required data from the packet.
  21          */
  22 @@ -1191,7 +1194,7 @@ int nf_conntrack_tcp_packet(struct nf_co
  23                  IP_CT_TCP_FLAG_DATA_UNACKNOWLEDGED &&
  24                  timeouts[new_state] > timeouts[TCP_CONNTRACK_UNACK])
  25                 timeout = timeouts[TCP_CONNTRACK_UNACK];
  26 -       else if (ct->proto.tcp.last_win == 0 &&
  27 +       else if (!tn->tcp_no_window_check && ct->proto.tcp.last_win == 0 &&
  28                  timeouts[new_state] > timeouts[TCP_CONNTRACK_RETRANS])
  29                 timeout = timeouts[TCP_CONNTRACK_RETRANS];
  30         else
  31 @@ -1507,6 +1510,9 @@ void nf_conntrack_tcp_init_net(struct ne
  32          */
  33         tn->tcp_be_liberal = 0;
  34
  35 +       /* Skip Windows Check */
  36 +       tn->tcp_no_window_check = 0;
  37 +
  38         /* If it's non-zero, we turn off RST sequence number check */
  39         tn->tcp_ignore_invalid_rst = 0;
  40
  41 --- a/net/netfilter/nf_conntrack_standalone.c
  42 +++ b/net/netfilter/nf_conntrack_standalone.c
  43 @@ -633,6 +633,7 @@ enum nf_ct_sysctl_index {
  44  #endif
  45         NF_SYSCTL_CT_PROTO_TCP_LOOSE,
  46         NF_SYSCTL_CT_PROTO_TCP_LIBERAL,
  47 +       NF_SYSCTL_CT_PROTO_TCP_NO_WINDOW_CHECK,
  48         NF_SYSCTL_CT_PROTO_TCP_IGNORE_INVALID_RST,
  49         NF_SYSCTL_CT_PROTO_TCP_MAX_RETRANS,
  50         NF_SYSCTL_CT_PROTO_TIMEOUT_UDP,
  51 @@ -848,6 +849,14 @@ static struct ctl_table nf_ct_sysctl_tab
  52                 .extra1         = SYSCTL_ZERO,
  53                 .extra2         = SYSCTL_ONE,
  54         },
  55 +       [NF_SYSCTL_CT_PROTO_TCP_NO_WINDOW_CHECK] = {
  56 +               .procname       = "nf_conntrack_tcp_no_window_check",
  57 +               .maxlen         = sizeof(u8),
  58 +               .mode           = 0644,
  59 +               .proc_handler   = proc_dou8vec_minmax,
  60 +               .extra1         = SYSCTL_ZERO,
  61 +               .extra2         = SYSCTL_ONE,
  62 +       },
  63         [NF_SYSCTL_CT_PROTO_TCP_IGNORE_INVALID_RST] = {
  64                 .procname       = "nf_conntrack_tcp_ignore_invalid_rst",
  65                 .maxlen         = sizeof(u8),
  66 @@ -1058,6 +1067,7 @@ static void nf_conntrack_standalone_init
  67
  68         XASSIGN(LOOSE, &tn->tcp_loose);
  69         XASSIGN(LIBERAL, &tn->tcp_be_liberal);
  70 +       XASSIGN(NO_WINDOW_CHECK, &tn->tcp_no_window_check);
  71         XASSIGN(MAX_RETRANS, &tn->tcp_max_retrans);
  72         XASSIGN(IGNORE_INVALID_RST, &tn->tcp_ignore_invalid_rst);
  73  #undef XASSIGN
  74 --- a/include/net/netns/conntrack.h
  75 +++ b/include/net/netns/conntrack.h
  76 @@ -26,6 +26,7 @@ struct nf_tcp_net {
  77         unsigned int timeouts[TCP_CONNTRACK_TIMEOUT_MAX];
  78         u8 tcp_loose;
  79         u8 tcp_be_liberal;
  80 +       u8 tcp_no_window_check;
  81         u8 tcp_max_retrans;
  82         u8 tcp_ignore_invalid_rst;
  83  #if IS_ENABLED(CONFIG_NF_FLOW_TABLE)