tcp: validate seq for handshake ack

[vpp.git] / src / vnet / tcp / tcp_input.c

diff --git a/src/vnet/tcp/tcp_input.c b/src/vnet/tcp/tcp_input.c
index f04fa5d..3959437 100644 (file)
--- a/src/vnet/tcp/tcp_input.c
+++ b/src/vnet/tcp/tcp_input.c
@@ -2724,6 +2724,14 @@ tcp46_rcv_process_inline (vlib_main_t * vm, vlib_node_runtime_t * node,
              goto drop;
            }
 
+         /* Make sure the ack is exactly right */
+         if (tc0->rcv_nxt != vnet_buffer (b0)->tcp.seq_number)
+           {
+             error0 = TCP_ERROR_SEGMENT_INVALID;
+             tcp_send_reset_w_pkt (tc0, b0, is_ip4);
+             goto drop;
+           }
+
          /* Update rtt and rto */
          tcp_estimate_initial_rtt (tc0);