From 5af685a9c5353caec9002372420911c8a5079ea5 Mon Sep 17 00:00:00 2001
From: Baptiste Courtois <b.courtois@criteo.com>
Date: Mon, 26 Nov 2018 19:13:57 +0100
Subject: [PATCH] auth: geoip - forbid 0 as weight value

In the case where the weight of all records is set to zero, former code
was trying to compute probability by dividing by 0.

Another motivation to forbid the use of the "zero" weight is that the
desired behavior was not clear.
---
 docs/backends/geoip.rst              | 2 +-
 modules/geoipbackend/geoipbackend.cc | 6 +++---
 2 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/docs/backends/geoip.rst b/docs/backends/geoip.rst
index b556bb1cc2..6667988c47 100644
--- a/docs/backends/geoip.rst
+++ b/docs/backends/geoip.rst
@@ -220,7 +220,7 @@ These placeholders disable caching for the record completely:
 Using the ``weight`` attribute
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
-You can use record attributes to define weight.
+You can use record attributes to define positive and non-zero weight.
 If this is given, only one record is chosen randomly based on the weight.
 
 Probability is calculated by summing up the weights and dividing each weight with the sum.
diff --git a/modules/geoipbackend/geoipbackend.cc b/modules/geoipbackend/geoipbackend.cc
index 5ed467b6dd..4baabe2fe7 100644
--- a/modules/geoipbackend/geoipbackend.cc
+++ b/modules/geoipbackend/geoipbackend.cc
@@ -150,9 +150,9 @@ void GeoIPBackend::initialize() {
                rr.content = content;
              } else if (attr == "weight") {
                rr.weight = iter->second.as<int>();
-               if (rr.weight < 0) {
-                 g_log<<Logger::Error<<"Weight cannot be negative for " << rr.qname << endl;
-                 throw PDNSException(string("Weight cannot be negative for ") + rr.qname.toLogString());
+               if (rr.weight <= 0) {
+                 g_log<<Logger::Error<<"Weight must be positive for " << rr.qname << endl;
+                 throw PDNSException(string("Weight must be positive for ") + rr.qname.toLogString());
                }
                rr.has_weight = true;
              } else if (attr == "ttl") {
-- 
2.47.2