From: Remi Gacogne <remi.gacogne@powerdns.com>
Date: Mon, 20 Apr 2020 13:10:56 +0000 (+0200)
Subject: auth: Make sure we don't divide by zero in Lua's pickwhashed()
X-Git-Tag: dnsdist-1.5.0-rc2~14^2
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=refs%2Fpull%2F9044%2Fhead;p=thirdparty%2Fpdns.git

auth: Make sure we don't divide by zero in Lua's pickwhashed()
---

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; });