From c7cd91db5d20e70990acd2d87f9acb625741ee25 Mon Sep 17 00:00:00 2001
From: Remi Gacogne <remi.gacogne@powerdns.com>
Date: Mon, 20 Apr 2020 15:10:56 +0200
Subject: [PATCH] auth: Make sure we don't divide by zero in Lua's
 pickwhashed()

---
 pdns/lua-record.cc | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/pdns/lua-record.cc b/pdns/lua-record.cc
index 7ef5bf6fe1..ca46307a37 100644
--- a/pdns/lua-record.cc
+++ b/pdns/lua-record.cc
@@ -344,6 +344,10 @@ static ComboAddress pickwhashed(const ComboAddress& bestwho, vector<pair<int,Com
     sum += i.first;
     pick.push_back({sum, i.second});
   }
+  if (sum == 0) {
+    /* we should not have any weight of zero, but better safe than sorry */
+    return ComboAddress();
+  }
   ComboAddress::addressOnlyHash aoh;
   int r = aoh(bestwho) % sum;
   auto p = upper_bound(pick.begin(), pick.end(), r, [](int rarg, const decltype(pick)::value_type& a) { return rarg < a.first; });
-- 
2.47.2