From: Otto Moerbeek <otto.moerbeek@open-xchange.com>
Date: Mon, 11 Mar 2024 16:34:02 +0000 (+0100)
Subject: selfresolve check wip
X-Git-Tag: rec-5.1.0-alpha1~82^2~12
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=0e107ef659537f47eab76f35e64806cb0783122a;p=thirdparty%2Fpdns.git

selfresolve check wip
---

diff --git a/pdns/recursordist/Makefile.am b/pdns/recursordist/Makefile.am
index 762f7a3762..56c5465977 100644
--- a/pdns/recursordist/Makefile.am
+++ b/pdns/recursordist/Makefile.am
@@ -248,7 +248,8 @@ pdns_recursor_LDADD = \
 	$(PROBDS_LIBS) \
 	$(LIBCAP_LIBS) \
 	$(ARC4RANDOM_LIBS) \
-	$(RUST_LIBS)
+	$(RUST_LIBS) \
+        -lresolv
 
 pdns_recursor_LDFLAGS = $(AM_LDFLAGS) \
 	$(LIBCRYPTO_LDFLAGS) $(BOOST_CONTEXT_LDFLAGS) \
@@ -403,7 +404,8 @@ testrunner_LDADD = \
 	$(PROBDS_LIBS) \
 	$(LIBCAP_LIBS) \
 	$(ARC4RANDOM_LIBS) \
-	$(RUST_LIBS)
+	$(RUST_LIBS) \
+        -lresolv
 
 if NOD_ENABLED
 testrunner_SOURCES +=   nod.hh nod.cc \
diff --git a/pdns/recursordist/configure.ac b/pdns/recursordist/configure.ac
index 241e0386d1..7485daf8f4 100644
--- a/pdns/recursordist/configure.ac
+++ b/pdns/recursordist/configure.ac
@@ -43,6 +43,7 @@ AC_SUBST([LIBDL], [$lt_cv_dlopen_libs])
 
 PDNS_CHECK_OS
 PDNS_CHECK_NETWORK_LIBS
+AC_SEARCH_LIBS([res_query], [resolv])
 PTHREAD_SET_NAME
 AC_FUNC_STRERROR_R
 
@@ -119,6 +120,7 @@ dnl the *_r functions are in posix so we can use them unconditionally, but the e
 dnl using the defines.
 AC_CHECK_FUNCS_ONCE([localtime_r gmtime_r strcasestr])
 AC_CHECK_FUNCS_ONCE([getrandom getentropy arc4random arc4random_uniform arc4random_buf])
+
 PDNS_CHECK_SECURE_MEMSET
 
 AC_CHECK_HEADERS([sys/random.h])
diff --git a/pdns/recursordist/rec-system-resolve.cc b/pdns/recursordist/rec-system-resolve.cc
index ced2c3eb46..6d7327454b 100644
--- a/pdns/recursordist/rec-system-resolve.cc
+++ b/pdns/recursordist/rec-system-resolve.cc
@@ -23,10 +23,16 @@
 #include <sys/types.h>
 #include <sys/socket.h>
 #include <netdb.h>
+#include <arpa/nameser.h>
+#include <resolv.h>
 
+#include "dnsparser.hh"
+#include "dnsrecords.hh"
 #include "rec-system-resolve.hh"
 #include "logging.hh"
+#include "noinitvector.hh"
 #include "threadname.hh"
+#include "syncres.hh"
 
 namespace
 {
@@ -46,6 +52,46 @@ ComboAddress resolve(const std::string& name)
   }
   return {};
 }
+
+PacketBuffer resolve(const string& name, QClass cls, QType type)
+{
+  PacketBuffer answer(512);
+  auto ret = res_query(name.c_str(), cls, type, answer.data(), static_cast<int>(answer.size()));
+  cerr << ret << endl;
+  if (ret == -1) {
+    answer.resize(0);
+  }
+  else {
+    answer.resize(ret);
+  }
+  return answer;
+}
+
+std::string serverID()
+{
+  auto buffer = resolve("id.server", QClass::CHAOS, QType::TXT);
+  if (buffer.empty()) {
+    cerr << "XXXXXXXXX SID case 1" << endl;
+    return {};
+  }
+  MOADNSParser parser(false,  reinterpret_cast<char *>(buffer.data()), buffer.size()); // NOLINT
+  if (parser.d_header.rcode != RCode::NoError || parser.d_answers.size() != 1) {
+    cerr << "XXXXXXXXX SID case 2" << endl;
+    return {};
+  }
+  const auto&  answer = parser.d_answers.at(0);
+  if (answer.first.d_type == QType::TXT) {
+    if (auto txt = getRR<TXTRecordContent>(answer.first); txt != nullptr) {
+      cerr << "XXXXXXXXX SID is " << txt->d_text << endl;
+      if (txt->d_text.size() >= 2) {
+        return txt->d_text.substr(1, txt->d_text.size() - 2);
+      }
+      return txt->d_text;
+    }
+  }
+    cerr << "XXXXXXXXX SID case 3" << endl;
+  return {};
+}
 } // anonymous namespace
 
 std::function<void()> pdns::RecResolve::s_callback;
@@ -184,6 +230,7 @@ pdns::RecResolve::Refresher::~Refresher()
 void pdns::RecResolve::Refresher::refreshLoop()
 {
   setThreadName("rec/sysres");
+  time_t lastSelfCheck = 0;
 
   while (!stop) {
     const time_t startTime = time(nullptr);
@@ -200,6 +247,15 @@ void pdns::RecResolve::Refresher::refreshLoop()
       if (stop) {
         break;
       }
+      if (lastSelfCheck < time(nullptr) - 60) {
+        lastSelfCheck = time(nullptr);
+        auto resolvedServerID = serverID();
+        cerr << "SyncRes::s_serverID " << SyncRes::s_serverID << endl;
+        if (resolvedServerID == SyncRes::s_serverID) {
+          auto log = g_slog->withName("system-resolver");
+          log->info(Logr::Error, "id.server/CH/TXT resolves to my own server identidy", "id.server", Logging::Loggable(resolvedServerID));
+        }
+      }
       changes = d_resolver.refresh(time(nullptr));
       wakeTime = time(nullptr);
       if (changes) {