From 446b3c865bbc43169aaa37fad230e4cbb700aaed Mon Sep 17 00:00:00 2001
From: moneromooo-monero <moneromooo-monero@users.noreply.github.com>
Date: Fri, 4 Dec 2020 13:59:51 +0000
Subject: [PATCH] p2p: drop peers that spam peer lists

There's always some people who just want to abuse things
---
 src/cryptonote_config.h | 1 +
 src/p2p/net_node.inl    | 5 +++++
 2 files changed, 6 insertions(+)

diff --git a/src/cryptonote_config.h b/src/cryptonote_config.h
index 826cabe17..13f0c471b 100644
--- a/src/cryptonote_config.h
+++ b/src/cryptonote_config.h
@@ -132,6 +132,7 @@
 #define P2P_DEFAULT_HANDSHAKE_INTERVAL                  60           //secondes
 #define P2P_DEFAULT_PACKET_MAX_SIZE                     50000000     //50000000 bytes maximum packet size
 #define P2P_DEFAULT_PEERS_IN_HANDSHAKE                  250
+#define P2P_MAX_PEERS_IN_HANDSHAKE                      250
 #define P2P_DEFAULT_CONNECTION_TIMEOUT                  5000       //5 seconds
 #define P2P_DEFAULT_SOCKS_CONNECT_TIMEOUT               45         // seconds
 #define P2P_DEFAULT_PING_CONNECTION_TIMEOUT             2000       //2 seconds
diff --git a/src/p2p/net_node.inl b/src/p2p/net_node.inl
index c71dfc2de..7dcc9d0bd 100644
--- a/src/p2p/net_node.inl
+++ b/src/p2p/net_node.inl
@@ -2060,6 +2060,11 @@ namespace nodetool
   template<class t_payload_net_handler>
   bool node_server<t_payload_net_handler>::handle_remote_peerlist(const std::vector<peerlist_entry>& peerlist, const epee::net_utils::connection_context_base& context)
   {
+    if (peerlist.size() > P2P_MAX_PEERS_IN_HANDSHAKE)
+    {
+      MWARNING(context << "peer sent " << peerlist.size() << " peers, considered spamming");
+      return false;
+    }
     std::vector<peerlist_entry> peerlist_ = peerlist;
     if(!sanitize_peerlist(peerlist_))
       return false;