From 26522d212b4b84ae4cbbdde8c7ab0ff55577a591 Mon Sep 17 00:00:00 2001
From: Alfredo Garcia <oxarbitrage@gmail.com>
Date: Wed, 24 Jun 2020 12:21:25 -0300
Subject: [PATCH] only allow duplicates for certain options of the config

---
 src/util.cpp | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/src/util.cpp b/src/util.cpp
index 82d705ea8..5d88aba88 100644
--- a/src/util.cpp
+++ b/src/util.cpp
@@ -627,10 +627,21 @@ void ReadConfigFile(const std::string& confPath,
     set<string> setOptions;
     setOptions.insert("*");
 
+    const vector<string> allowed_duplicates = {"addnode", "connect", "rpcallowip"};
+    set<string> unique_options;
+
     for (boost::program_options::detail::config_file_iterator it(streamConfig, setOptions), end; it != end; ++it)
     {
         string strKey = string("-") + it->string_key;
         string strValue = it->value[0];
+
+        if (find(allowed_duplicates.begin(), allowed_duplicates.end(), it->string_key) == allowed_duplicates.end())
+        {
+            if (!unique_options.insert(strKey).second) {
+                throw std::runtime_error(strprintf("Not allowed duplicated option %s found.", strKey));
+            }
+        }
+
         InterpretNegativeSetting(strKey, strValue);
         // Don't overwrite existing settings so command line settings override zcash.conf
         if (mapSettingsRet.count(strKey) == 0)