From: Remi Gacogne <remi.gacogne@powerdns.com>
Date: Wed, 7 Nov 2018 14:41:17 +0000 (+0100)
Subject: Revert "rec: Authority records in AA=1 CNAME answer are authoritative"
X-Git-Tag: auth-4.2.0-alpha1~58^2
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=bb2f7d9a707d2fa586532ae17e51828c2a36135b;p=pdns

Revert "rec: Authority records in AA=1 CNAME answer are authoritative"

This reverts commit cdc5d0c09ac148c805e91411d863b04b144ebbf9.

It turns out that authority records in AA=1 CNAME answer may, or may
not, be authoritative, and that in some cases considering them as
authoritative causes DNSSEC validation failures.
---

diff --git a/pdns/recursordist/test-syncres_cc.cc b/pdns/recursordist/test-syncres_cc.cc
index c6c8782b8..505310c98 100644
--- a/pdns/recursordist/test-syncres_cc.cc
+++ b/pdns/recursordist/test-syncres_cc.cc
@@ -10119,72 +10119,6 @@ BOOST_AUTO_TEST_CASE(test_getDSRecords_multialgo_two_highest) {
   }
 }
 
-BOOST_AUTO_TEST_CASE(test_cname_plus_authority_auth) {
-  std::unique_ptr<SyncRes> sr;
-  initSR(sr);
-
-  primeHints();
-
-  const DNSName target("cname.powerdns.com.");
-  const DNSName cnameTarget("cname-target.powerdns.com");
-  size_t queriesCount = 0;
-
-  sr->setAsyncCallback([target, cnameTarget, &queriesCount](const ComboAddress& ip, const DNSName& domain, int type, bool doTCP, bool sendRDQuery, int EDNS0Level, struct timeval* now, boost::optional<Netmask>& srcmask, boost::optional<const ResolveContext&> context, LWResult* res, bool* chained) {
-
-      queriesCount++;
-
-      if (isRootServer(ip)) {
-        setLWResult(res, 0, false, false, true);
-        addRecordToLW(res, DNSName("powerdns.com"), QType::NS, "a.gtld-servers.net.", DNSResourceRecord::AUTHORITY, 172800);
-        addRecordToLW(res, "a.gtld-servers.net.", QType::A, "192.0.2.1", DNSResourceRecord::ADDITIONAL, 3600);
-        return 1;
-      } else if (ip == ComboAddress("192.0.2.1:53")) {
-
-        if (domain == target) {
-          setLWResult(res, 0, true, false, false);
-          addRecordToLW(res, domain, QType::CNAME, cnameTarget.toString());
-          addRecordToLW(res, cnameTarget, QType::A, "192.0.2.2");
-          addRecordToLW(res, DNSName("powerdns.com."), QType::NS, "a.gtld-servers.net.", DNSResourceRecord::AUTHORITY, 42);
-          addRecordToLW(res, DNSName("add.powerdns.com."), QType::A, "192.0.2.3", DNSResourceRecord::ADDITIONAL, 42);
-          return 1;
-        }
-        else if (domain == cnameTarget) {
-          setLWResult(res, 0, true, false, false);
-          addRecordToLW(res, domain, QType::A, "192.0.2.2");
-        }
-
-        return 1;
-      }
-
-      return 0;
-    });
-
-  const time_t now = sr->getNow().tv_sec;
-  vector<DNSRecord> ret;
-  int res = sr->beginResolve(target, QType(QType::A), QClass::IN, ret);
-  BOOST_CHECK_EQUAL(res, RCode::NoError);
-  BOOST_REQUIRE_EQUAL(ret.size(), 2);
-  BOOST_CHECK(ret[0].d_type == QType::CNAME);
-  BOOST_CHECK_EQUAL(ret[0].d_name, target);
-  BOOST_CHECK(ret[1].d_type == QType::A);
-  BOOST_CHECK_EQUAL(ret[1].d_name, cnameTarget);
-
-  /* check that the NS in authority has been replaced in the cache
-     with auth=1, but that the part in additional is still not auth */
-  const ComboAddress who;
-  vector<DNSRecord> cached;
-  bool wasAuth = false;
-
-  BOOST_REQUIRE_GE(t_RC->get(now, DNSName("powerdns.com."), QType(QType::NS), false, &cached, who, nullptr, nullptr, nullptr, nullptr, &wasAuth), 1);
-  BOOST_CHECK_EQUAL(cached.size(), 1);
-  BOOST_CHECK_EQUAL(wasAuth, true);
-
-  cached.clear();
-  BOOST_REQUIRE_GE(t_RC->get(now, DNSName("add.powerdns.com."), QType(QType::A), false, &cached, who, nullptr, nullptr, nullptr, nullptr, &wasAuth), 1);
-  BOOST_CHECK_EQUAL(cached.size(), 1);
-  BOOST_CHECK_EQUAL(wasAuth, false);
-}
-
 /*
 // cerr<<"asyncresolve called to ask "<<ip.toStringWithPort()<<" about "<<domain.toString()<<" / "<<QType(type).getName()<<" over "<<(doTCP ? "TCP" : "UDP")<<" (rd: "<<sendRDQuery<<", EDNS0 level: "<<EDNS0Level<<")"<<endl;
 
diff --git a/pdns/syncres.cc b/pdns/syncres.cc
index 84ae05c70..0b892d2a9 100644
--- a/pdns/syncres.cc
+++ b/pdns/syncres.cc
@@ -2123,7 +2123,7 @@ RCode::rcodes_ SyncRes::updateCacheFromRecords(unsigned int depth, LWResult& lwr
        set the TC bit solely because these RRSIG RRs didn't fit."
     */
     bool isAA = lwr.d_aabit && i->first.place != DNSResourceRecord::ADDITIONAL;
-    if (isAA && isCNAMEAnswer && i->first.place == DNSResourceRecord::ANSWER && (i->first.type != QType::CNAME || i->first.name != qname)) {
+    if (isAA && isCNAMEAnswer && (i->first.place != DNSResourceRecord::ANSWER || i->first.type != QType::CNAME || i->first.name != qname)) {
       /*
         rfc2181 states:
         Note that the answer section of an authoritative answer normally