From 06b309b7f23fa96af1b00c524c7f7a06a2f98844 Mon Sep 17 00:00:00 2001
From: Peter van Dijk <peter.van.dijk@powerdns.com>
Date: Mon, 25 Nov 2019 13:05:22 +0100
Subject: [PATCH] LUA view: do not crash on empty IP list, fixes #8572

(cherry picked from commit 28beeb0f76f2ba0dcea0def88fe46dbce51d06eb)
---
 pdns/lua-record.cc | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/pdns/lua-record.cc b/pdns/lua-record.cc
index 623b4bee07..fa7a9a0c6c 100644
--- a/pdns/lua-record.cc
+++ b/pdns/lua-record.cc
@@ -863,6 +863,9 @@ std::vector<shared_ptr<DNSRecordContent>> luaSynth(const std::string& code, cons
         for(const auto& nmpair : netmasks) {
           Netmask nm(nmpair.second);
           if(nm.match(bestwho)) {
+            if (destinations.empty()) {
+              throw std::invalid_argument("The IP list cannot be empty (for netmask " + nm.toString() + ")");
+            }
             return destinations[dns_random(destinations.size())].second;
           }
         }
-- 
2.47.2