From 5d281d0e6ebc9fd8bcc233985641d31f023b7ddd Mon Sep 17 00:00:00 2001
From: dmiller <dmiller@e0a8ed71-7df4-0310-8962-fdc924857419>
Date: Tue, 18 Feb 2020 17:02:39 +0000
Subject: [PATCH] Avoid infinite runtime in snmp-brute due to 'Invalid reuse of
 a socket' killing send thread.

---
 scripts/snmp-brute.nse | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/scripts/snmp-brute.nse b/scripts/snmp-brute.nse
index 904cc88f2..450b3ca4a 100644
--- a/scripts/snmp-brute.nse
+++ b/scripts/snmp-brute.nse
@@ -180,6 +180,11 @@ local sniff_snmp_responses = function(host, port, lport, result)
 
   -- receive even when status=false until all the probes are sent
   while true do
+    if coroutine.status(result.main_thread) == "dead" then
+      -- Oops, main thread quit. Time to bail.
+      return
+    end
+
     local status, plen, l2, l3, _ = pcap:pcap_receive()
 
     if status then
@@ -204,7 +209,7 @@ local sniff_snmp_responses = function(host, port, lport, result)
         return
       end
     else
-      if last_run then
+      if last_run or not result.status then
         condvar "signal"
         return
       else
@@ -236,6 +241,7 @@ action = function(host, port)
   result.sent = false --whether the probes are sent
   result.msg = "" -- Error/Status msg
   result.status = true -- Status (is everything ok)
+  result.main_thread = coroutine.running() -- to check if the main thread is dead.
 
   local socket = nmap.new_socket("udp")
   status = socket:connect(host, port)
@@ -257,6 +263,7 @@ action = function(host, port)
     condvar "wait"
     recv_dead = (coroutine.status(recv_co) == "dead")
     send_dead = (coroutine.status(send_co) == "dead")
+    if send_dead then result.sent = true end
     if recv_dead then break end
   end