From 46d6fa35c9c3f5257a31bc4dae89a102a441831b Mon Sep 17 00:00:00 2001
From: moneromooo-monero <moneromooo-monero@users.noreply.github.com>
Date: Thu, 7 Dec 2017 22:22:14 +0000
Subject: [PATCH] cryptonote_protocol: sanity check chain hashes from peer

---
 src/cryptonote_protocol/cryptonote_protocol_handler.inl | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/src/cryptonote_protocol/cryptonote_protocol_handler.inl b/src/cryptonote_protocol/cryptonote_protocol_handler.inl
index dbcc4eba1..de30df5d7 100644
--- a/src/cryptonote_protocol/cryptonote_protocol_handler.inl
+++ b/src/cryptonote_protocol/cryptonote_protocol_handler.inl
@@ -1585,6 +1585,12 @@ skip:
       drop_connection(context, true, false);
       return 1;
     }
+    if (arg.total_height < arg.m_block_ids.size() || arg.start_height > arg.total_height - arg.m_block_ids.size())
+    {
+      LOG_ERROR_CCONTEXT("sent invalid start/nblocks/height, dropping connection");
+      drop_connection(context, true, false);
+      return 1;
+    }
 
     context.m_remote_blockchain_height = arg.total_height;
     context.m_last_response_height = arg.start_height + arg.m_block_ids.size()-1;