From d8ec8f441d08511b76ece3215c73b952bc1f56db Mon Sep 17 00:00:00 2001
From: Remi Gacogne <remi.gacogne@powerdns.com>
Date: Mon, 13 Jun 2016 18:44:40 +0200
Subject: [PATCH] Fix usage of std::distance() in DNSName::isPartOf()

---
 pdns/dnsname.cc | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/pdns/dnsname.cc b/pdns/dnsname.cc
index 1c81ea10f2..82bc2fe90e 100644
--- a/pdns/dnsname.cc
+++ b/pdns/dnsname.cc
@@ -200,8 +200,12 @@ bool DNSName::isPartOf(const DNSName& parent) const
     return false;
 
   // this is slightly complicated since we can't start from the end, since we can't see where a label begins/ends then
-  for(auto us=d_storage.cbegin(); us<d_storage.cend() && std::distance(us,d_storage.cend()) >= static_cast<unsigned int>(parent.d_storage.size()); us+=*us+1) {
-    if (std::distance(us,d_storage.cend()) == static_cast<unsigned int>(parent.d_storage.size())) {
+  for(auto us=d_storage.cbegin(); us<d_storage.cend(); us+=*us+1) {
+    auto distance = std::distance(us,d_storage.cend());
+    if (distance < 0 || static_cast<size_t>(distance) < parent.d_storage.size()) {
+      break;
+    }
+    if (static_cast<size_t>(distance) == parent.d_storage.size()) {
       auto p = parent.d_storage.cbegin();
       for(; us != d_storage.cend(); ++us, ++p) {
         if(dns2_tolower(*p) != dns2_tolower(*us))
-- 
2.47.2