From: Otto Moerbeek <otto.moerbeek@open-xchange.com>
Date: Mon, 21 Feb 2022 15:11:37 +0000 (+0100)
Subject: Drop queries with packet types we do not like.
X-Git-Tag: rec-4.7.0-alpha1~5^2~1
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=cfbcc0f3891e5a62cef7a0258056fad8dbfcdf47;p=thirdparty%2Fpdns.git

Drop queries with packet types we do not like.

While working on this, I noticed inconsistencies between UDP and TDP logging:
1 uses g_quiet, the other g_logCommonErrors. This needs to be revisited.

Also: the use of MT->getTid() seems strange, as it is used in places where
no mthread has been started yet in doProcessUDPQuestion() and handleRunningTCPQuestion().
That is, unless I'm missing something.
---

diff --git a/pdns/pdns_recursor.cc b/pdns/pdns_recursor.cc
index 8d07675df7..2e7093995c 100644
--- a/pdns/pdns_recursor.cc
+++ b/pdns/pdns_recursor.cc
@@ -1999,6 +1999,16 @@ static string* doProcessUDPQuestion(const std::string& question, const ComboAddr
   }
 
   auto dc = std::make_unique<DNSComboWriter>(question, g_now, std::move(policyTags), t_pdl, std::move(data), std::move(records));
+
+  if (SyncRes::isUnsupported(dc->d_mdp.d_qtype)) {
+    g_stats.ignoredCount++;
+    if (!g_quiet) {
+      g_log << Logger::Notice << RecThreadInfo::id() << " Unsupported qtype " << dc->d_mdp.d_qtype << " from " << source.toStringWithPort() << (source != fromaddr ? " (via " + fromaddr.toStringWithPort() + ")" : "") << endl;
+    }
+
+    return 0;
+  }
+
   dc->setSocket(fd);
   dc->d_tag = ctag;
   dc->d_qhash = qhash;
diff --git a/pdns/recursordist/rec-taskqueue.cc b/pdns/recursordist/rec-taskqueue.cc
index 1e6593006a..883b26087d 100644
--- a/pdns/recursordist/rec-taskqueue.cc
+++ b/pdns/recursordist/rec-taskqueue.cc
@@ -181,13 +181,8 @@ void runTaskOnce(bool logErrors)
 
 void pushAlmostExpiredTask(const DNSName& qname, uint16_t qtype, time_t deadline)
 {
-  switch (qtype) {
-    // Internal types
-  case QType::ENT:
-  case QType::ADDR:
-  case QType::ALIAS:
-  case QType::LUA:
-    g_log << Logger::Debug << "Cannot push task for " << QType(qtype).toString() << endl;
+  if (SyncRes::isUnsupported(qtype)) {
+    g_log << Logger::Error << "Cannot push task for " << QType(qtype).toString() << endl;
     return;
   }
   pdns::ResolveTask task{qname, qtype, deadline, true, resolve};
diff --git a/pdns/recursordist/rec-tcp.cc b/pdns/recursordist/rec-tcp.cc
index 807b3dce1c..9e46bf7c1e 100644
--- a/pdns/recursordist/rec-tcp.cc
+++ b/pdns/recursordist/rec-tcp.cc
@@ -338,6 +338,14 @@ static void handleRunningTCPQuestion(int fd, FDMultiplexer::funcparam_t& var)
         }
         return;
       }
+      if (SyncRes::isUnsupported(dc->d_mdp.d_qtype)) {
+        g_stats.ignoredCount++;
+        if (g_logCommonErrors) {
+          g_log << Logger::Error << "Unsupported qtype " << dc->d_mdp.d_qtype << " from TCP client " << conn->d_remote.toStringWithPort() << endl;
+        }
+        return;
+      }
+
       dc->d_tcpConnection = conn; // carry the torch
       dc->setSocket(conn->getFD()); // this is the only time a copy is made of the actual fd
       dc->d_tcp = true;
diff --git a/pdns/syncres.hh b/pdns/syncres.hh
index dddf299e95..815724e355 100644
--- a/pdns/syncres.hh
+++ b/pdns/syncres.hh
@@ -736,6 +736,19 @@ public:
     d_queryReceivedOverTCP = tcp;
   }
 
+  static bool isUnsupported(QType qtype)
+  {
+    switch (qtype.getCode()) {
+      // Internal types
+    case QType::ENT:
+    case QType::ADDR:
+    case QType::ALIAS:
+    case QType::LUA:
+      return true;
+    }
+    return false;
+  }
+
   static thread_local ThreadLocalStorage t_sstorage;
 
   static pdns::stat_t s_queries;