diff -up nmap-5.51/nmap_dns.cc.tcpdns nmap-5.51/nmap_dns.cc

--- a/nmap_dns.cc	2011-01-21 01:04:16.000000000 +0100

+++ b/nmap_dns.cc	2016-10-26 11:04:49.057723356 +0200

@@ -677,9 +677,9 @@ static void read_evt_handler(nsock_pool

   packet_id = buf[1] + (buf[0] << 8);

-  // Check that this is a response, standard query, and that no truncation was performed

+  // Check that this is a response, standard query

   // 0xFA == 11111010 (we're not concerned with AA or RD bits)

-  if ((buf[2] & 0xFA) != 0x80) return;

+  if ((buf[2] & 0xF8) != 0x80) return;

   // Check that the zero field is all zeros and there is no error condition.

   // We don't care if recursion is available or not since we might be querying

@@ -715,7 +715,8 @@ static void read_evt_handler(nsock_pool

     return;

   }

-  if (queries <= 0 || answers <= 0) return;

+  bool processing_successful = false;

+//   if (queries <= 0 || answers <= 0) return;

   curbuf = 12;

@@ -732,7 +733,7 @@ static void read_evt_handler(nsock_pool

   // We're now at the ANSWER section

-  for (i=0; i

+  for (i=0; i

     curbuf = advance_past_dns_name(buf, buflen, curbuf, &nameloc);

     if (curbuf == -1) return;

@@ -758,7 +759,7 @@ static void read_evt_handler(nsock_pool

       if (encoded_name_to_normal(buf+nameloc, outbuf, sizeof(outbuf)) == -1) return;

-      if (process_result(ia.s_addr, outbuf, ACTION_FINISHED, packet_id)) {

+      if ((processing_successful = process_result(ia.s_addr, outbuf, ACTION_FINISHED, packet_id))) {

         if (o.debugging >= TRACE_DEBUG_LEVEL) log_write(LOG_STDOUT, "mass_rdns: OK MATCHED <%s> to <%s>\n", inet_ntoa(ia), outbuf);

         output_summary();

         stat_ok++;

@@ -771,15 +772,26 @@ static void read_evt_handler(nsock_pool

       if (ia.s_addr == 0) return;

       if (o.debugging >= TRACE_DEBUG_LEVEL) log_write(LOG_STDOUT, "mass_rdns: CNAME found for <%s>\n", inet_ntoa(ia));

-      process_result(ia.s_addr, NULL, ACTION_CNAME_LIST, packet_id);

+      processing_successful = process_result(ia.s_addr, NULL, ACTION_SYSTEM_RESOLVE, packet_id);

     } else {

       if (rdlen < 0 || rdlen + curbuf >= buflen) return;

       curbuf += rdlen;

     }

-    if (curbuf >= buflen) return;

+    if (curbuf >= buflen) break;//return;

   }

+  if (!processing_successful) {

+    if ((buf[2] & 0x02)) { //truncated

+      u32 discard = 0;

+      process_result(discard, NULL, ACTION_SYSTEM_RESOLVE, packet_id);

+    }

+    else {

+      if (o.debugging >= TRACE_DEBUG_LEVEL) {

+        log_write(LOG_STDOUT, "mass_rdns: Unable to process the response\n");

+      }

+    }

+  }

 }

@@ -1225,20 +1237,20 @@ static void nmap_mass_rdns_core(Target *

   nsp_delete(dnspool);

-  if (cname_reqs.size() && o.debugging)

-    log_write(LOG_STDOUT, "Performing system-dns for %d domain names that use CNAMEs\n", (int) cname_reqs.size());

+  if (deferred_reqs.size() && o.debugging)

+    log_write(LOG_STDOUT, "Performing system-dns for %d domain names that were deferred\n", (int) deferred_reqs.size());

-  if (cname_reqs.size()) {

-    Snprintf(spmobuf, sizeof(spmobuf), "System CNAME DNS resolution of %u host%s.", (unsigned) cname_reqs.size(), cname_reqs.size()-1 ? "s" : "");

+  if (deferred_reqs.size()) {

+    Snprintf(spmobuf, sizeof(spmobuf), "System DNS resolution of %u host%s.", (unsigned) deferred_reqs.size(), deferred_reqs.size()-1 ? "s" : "");

     SPM = new ScanProgressMeter(spmobuf);

-    for(i=0, reqI = cname_reqs.begin(); reqI != cname_reqs.end(); reqI++, i++) {

+    for(i=0, reqI = deferred_reqs.begin(); reqI != deferred_reqs.end(); reqI++, i++) {

       struct sockaddr_storage ss;

       size_t sslen;

       char hostname[MAXHOSTNAMELEN + 1] = "";

       if (keyWasPressed())

-        SPM->printStats((double) i / cname_reqs.size(), NULL);

+        SPM->printStats((double) i / deferred_reqs.size(), NULL);

       tpreq = *reqI;

diff --git a/nmap_dns.cc b/nmap_dns.cc

index 9a72336..e01230c 100644

--- a/nmap_dns.cc

+++ b/nmap_dns.cc

@@ -309,7 +309,7 @@ struct host_elem {

 static std::list<dns_server> servs;

 static std::list<request *> new_reqs;

-static std::list<request *> cname_reqs;

+static std::list<request *> deferred_reqs;

 static int total_reqs;

 static nsock_pool dnspool=NULL;

diff --git a/nmap_dns.cc b/nmap_dns.cc

index e01230c..540d39d 100644

--- a/nmap_dns.cc

+++ b/nmap_dns.cc

@@ -327,12 +327,13 @@ static ScanProgressMeter *SPM;

 //------------------- Prototypes and macros ---------------------

+static void read_evt_handler(nsock_pool, nsock_event, void *);

 static void put_dns_packet_on_wire(request *req);

 static const char *lookup_etchosts(u32 ip);

 static void addto_etchosts(u32 ip, const char *hname);

 #define ACTION_FINISHED 0

-#define ACTION_CNAME_LIST 1

+#define ACTION_SYSTEM_RESOLVE 1

 #define ACTION_TIMEOUT 2

 //------------------- Misc code ---------------------

diff --git a/nmap_dns.cc b/nmap_dns.cc

index 540d39d..e0c6f6c 100644

--- a/nmap_dns.cc

+++ b/nmap_dns.cc

@@ -1240,7 +1240,7 @@ static void nmap_mass_rdns_core(Target **targets, int num_targets) {

   connect_dns_servers();

-  cname_reqs.clear();

+  deferred_reqs.clear();

   read_timeout_index = MIN(sizeof(read_timeouts)/sizeof(read_timeouts[0]), servs.size()) - 1;

diff --git a/nmap_dns.cc b/nmap_dns.cc

index 9363614..815b3a4 100644

--- a/nmap_dns.cc

+++ b/nmap_dns.cc

@@ -558,7 +558,7 @@ static int process_result(u32 ia, char *result, int action, u16 id) {

         if (ia != 0 && tpreq->targ->v4host().s_addr != ia)

           continue;

-        if (action == ACTION_CNAME_LIST || action == ACTION_FINISHED) {

+        if (action == ACTION_SYSTEM_RESOLVE || action == ACTION_FINISHED) {

         servI->capacity += CAPACITY_UP_STEP;

         check_capacities(&*servI);

@@ -572,7 +572,7 @@ static int process_result(u32 ia, char *result, int action, u16 id) {

         total_reqs--;

-          if (action == ACTION_CNAME_LIST) cname_reqs.push_back(tpreq);

+          if (action == ACTION_SYSTEM_RESOLVE) deferred_reqs.push_back(tpreq);

           if (action == ACTION_FINISHED) delete tpreq;

         } else {

           memcpy(&tpreq->timeout, nsock_gettimeofday(), sizeof(struct timeval));

diff --git a/nmap_dns.cc b/nmap_dns.cc

index 815b3a4..f00ac18 100644

--- a/nmap_dns.cc

+++ b/nmap_dns.cc

@@ -1302,7 +1302,7 @@ static void nmap_mass_rdns_core(Target **targets, int num_targets) {

     delete SPM;

   }

-  cname_reqs.clear();

+  deferred_reqs.clear();

 }