From: Mark Zealey <mark@markandruth.co.uk>
Date: Wed, 10 Jul 2019 11:17:32 +0000 (+0300)
Subject: Fix SERVFAIL when backend returns empty DNSName
X-Git-Tag: dnsdist-1.4.0-rc1~56^2
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=41147d678b30612d2431b59a898879368f1c4b06;p=pdns

Fix SERVFAIL when backend returns empty DNSName

According to the documentation on UeberBackend::getAuth(), a backend
returning an empty DNSName should signal that no matching parent zone
exists in this backend. However commit ae14c1f36a raises an exception if
isPartOf() is called on an empty DNSName so we need to switch the order
of the logic to prevent a SERVFAIL as a result.
---

diff --git a/pdns/ueberbackend.cc b/pdns/ueberbackend.cc
index 2c3dd363b..e33b9030e 100644
--- a/pdns/ueberbackend.cc
+++ b/pdns/ueberbackend.cc
@@ -330,7 +330,7 @@ bool UeberBackend::getAuth(const DNSName &target, const QType& qtype, SOAData* s
           DLOG(g_log<<Logger::Error<<"lookup: "<<shorter<<endl);
           if((*i)->getAuth(shorter, sd)) {
             DLOG(g_log<<Logger::Error<<"got: "<<sd->qname<<endl);
-            if(!shorter.isPartOf(sd->qname) && !sd->qname.empty()) {
+            if(!sd->qname.empty() && !shorter.isPartOf(sd->qname)) {
               throw PDNSException("getAuth() returned an SOA for the wrong zone. Zone '"+sd->qname.toLogString()+"' is not part of '"+shorter.toLogString()+"'");
             }
             j->first = sd->qname.wirelength();