rec: backport CVE-2024-25583 to rel/rec-4.9.5-branch

A name can be present already when building the cname chain.

diff --git a/pdns/recursordist/syncres.cc b/pdns/recursordist/syncres.cc
index 3eac692166be3e4fc89bdb1198038ed450bebe8f..812e36732149b21890517697bcccddc74a562718 100644 (file)
--- a/pdns/recursordist/syncres.cc
+++ b/pdns/recursordist/syncres.cc
@@ -4345,7 +4345,10 @@ RCode::rcodes_ SyncRes::updateCacheFromRecords(unsigned int depth, const string&
         break;
       }
       initial = cnameIt->second;
-      wildcardCandidates.emplace(initial, false);
+      if (!wildcardCandidates.emplace(initial, false).second) {
+        // CNAME Loop
+        break;
+      }
     }
   }
 

diff --git a/pdns/recursordist/test-syncres_cc1.cc b/pdns/recursordist/test-syncres_cc1.cc
index 3676524d3c09bb54672e2d92f21528b0ac4a1230..fa103c18632060b78acb176c4e7472dfe6064fd7 100644 (file)
--- a/pdns/recursordist/test-syncres_cc1.cc
+++ b/pdns/recursordist/test-syncres_cc1.cc
@@ -1629,6 +1629,54 @@ BOOST_AUTO_TEST_CASE(test_cname_loop)
   }
 }
 
+BOOST_AUTO_TEST_CASE(test_cname_loop_forwarder)
+{
+  std::unique_ptr<SyncRes> resolver;
+  initSR(resolver);
+
+  primeHints();
+
+  size_t count = 0;
+  const DNSName target("cname.powerdns.com.");
+  const DNSName cname1("cname1.cname.powerdns.com.");
+  const DNSName cname2("cname2.cname.powerdns.com.");
+
+  SyncRes::AuthDomain ad;
+  const std::vector<ComboAddress> forwardedNSs{ComboAddress("192.0.2.42:53")};
+  ad.d_rdForward = true;
+  ad.d_servers = forwardedNSs;
+  (*SyncRes::t_sstorage.domainmap)[target] = ad;
+
+  resolver->setAsyncCallback([&](const ComboAddress& address, 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 */) {
+    count++;
+
+    if (isRootServer(address)) {
+
+      setLWResult(res, 0, false, false, true);
+      addRecordToLW(res, domain, 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 LWResult::Result::Success;
+    }
+    if (address == ComboAddress("192.0.2.42:53")) {
+
+      if (domain == target) {
+        setLWResult(res, 0, true, false, false);
+        addRecordToLW(res, domain, QType::CNAME, cname1.toString());
+        addRecordToLW(res, cname1, QType::CNAME, cname2.toString());
+        addRecordToLW(res, cname2, QType::CNAME, domain.toString());
+        return LWResult::Result::Success;
+      }
+
+      return LWResult::Result::Success;
+    }
+
+    return LWResult::Result::Timeout;
+  });
+
+  vector<DNSRecord> ret;
+  BOOST_REQUIRE_THROW(resolver->beginResolve(target, QType(QType::A), QClass::IN, ret), ImmediateServFailException);
+}
+
 BOOST_AUTO_TEST_CASE(test_cname_long_loop)
 {
   std::unique_ptr<SyncRes> sr;