From feb47aed193a4bfa3b8ec07ae70ad44a1cfbff12 Mon Sep 17 00:00:00 2001
From: Otto Moerbeek <otto.moerbeek@open-xchange.com>
Date: Mon, 28 Oct 2019 16:57:46 +0100
Subject: [PATCH] It is better to make sure . entries are not added to the set.

---
 pdns/reczones.cc | 16 +++++++++++-----
 1 file changed, 11 insertions(+), 5 deletions(-)

diff --git a/pdns/reczones.cc b/pdns/reczones.cc
index 4fd2c32f44..505a18402e 100644
--- a/pdns/reczones.cc
+++ b/pdns/reczones.cc
@@ -34,6 +34,14 @@ extern char** g_argv;
 
 static thread_local set<DNSName> t_rootNSZones;
 
+static void insertIntoRootNSZones(const DNSName &name) {
+  // do not insert dot, wiping dot's NS records from the cache in primeRootNSZones()
+  // will cause infinite recursion
+  if (!name.isRoot()) {
+    t_rootNSZones.insert(name);
+  }
+}
+
 void primeHints(void)
 {
   // prime root cache
@@ -57,7 +65,7 @@ void primeHints(void)
       templ[sizeof(templ)-1] = '\0';
       *templ=c;
       aaaarr.d_name=arr.d_name=DNSName(templ);
-      t_rootNSZones.insert(arr.d_name.getLastLabel());
+      insertIntoRootNSZones(arr.d_name.getLastLabel());
       nsrr.d_content=std::make_shared<NSRecordContent>(DNSName(templ));
       arr.d_content=std::make_shared<ARecordContent>(ComboAddress(rootIps4[c-'a']));
       vector<DNSRecord> aset;
@@ -92,7 +100,7 @@ void primeHints(void)
         rr.content=toLower(rr.content);
         nsset.push_back(DNSRecord(rr));
       }
-      t_rootNSZones.insert(rr.qname.getLastLabel());
+      insertIntoRootNSZones(rr.qname.getLastLabel());
     }
   }
   t_RC->doWipeCache(g_rootdnsname, false, QType::NS);
@@ -119,9 +127,7 @@ void primeRootNSZones(bool dnssecmode)
     sr.setDNSSECValidationRequested(true);
   }
   for (const auto & qname: t_rootNSZones) {
-    if (!qname.isRoot()) {
-      t_RC->doWipeCache(qname, false, QType::NS);
-    }
+    t_RC->doWipeCache(qname, false, QType::NS);
     vector<DNSRecord> ret;
     sr.beginResolve(qname, QType(QType::NS), QClass::IN, ret);
   }
-- 
2.47.2