Adds broadcast-jenkins-discover to discover Jenkins servers. Closes #1236

CHANGELOG

@@ -1,5 +1,8 @@
 #Nmap Changelog ($Id$); -*-text-*-
 
+o [NSE][GH#1236] Added broadcast-jenkins-discover to discover Jenkins servers
+  on a LAN by sending a discovery broadcast probe. [Brendan Coles]
+
 o [NSE][GH#1232] Added broadcast-hid-discoveryd to discover HID devices 
   on a LAN by sending a discoveryd network broadcast probe. [Brendan Coles]
 

scripts/broadcast-jenkins-discover.nse

@@ -0,0 +1,100 @@
+local nmap = require "nmap"
+local packet = require "packet"
+local stdnse = require "stdnse"
+local string = require "string"
+local target = require "target"
+
+description = [[
+Discovers Jenkins servers on a LAN by sending a discovery broadcast probe.
+
+For more information about Jenkins auto discovery, see:
+* https://wiki.jenkins.io/display/JENKINS/Auto-discovering+Jenkins+on+the+network
+]]
+
+---
+-- @usage nmap --script broadcast-jenkins-discover
+-- @usage nmap --script broadcast-jenkins-discover --script-args timeout=15s
+--
+-- @output
+-- Pre-scan script results:
+-- | broadcast-jenkins: 
+-- |   Version: 2.60.2; Server ID: d5e31b7a9d69cf3c89cc799c23199760; Slave Port: 35928
+-- |   Version: 2.60.2; Server ID: b98e8e1b862c3eecb14e8be0028cf4ee; Slave Port: 45435
+-- |_  Use --script-args=newtargets to add the results as targets
+--
+-- @args broadcast-jenkins.address
+--       address to which the probe packet is sent. (default: 255.255.255.255)
+-- @args broadcast-jenkins.timeout
+--       socket timeout (default: 5s)
+---
+
+author = "Brendan Coles"
+license = "Same as Nmap--See https://nmap.org/book/man-legal.html"
+categories = {"discovery", "broadcast", "safe"}
+
+prerule = function() return ( nmap.address_family() == "inet") end
+
+local arg_address = stdnse.get_script_args(SCRIPT_NAME .. ".address")
+local arg_timeout = stdnse.parse_timespec(stdnse.get_script_args(SCRIPT_NAME .. ".timeout"))
+
+action = function()
+
+  local host = { ip = arg_address or "255.255.255.255" } -- broadcast
+  -- local host = { ip = arg_address or "239.77.124.213" } -- multicast
+  local port = { number = 33848, protocol = "udp" }
+  local socket = nmap.new_socket("udp")
+
+  socket:set_timeout(500)
+
+  -- send two packets, just in case
+  local probe = stdnse.generate_random_string(10)
+  for i=1,2 do
+    local status = socket:sendto(host, port, probe)
+    if ( not(status) ) then
+      return stdnse.format_output(false, "Failed to send broadcast probe")
+    end
+  end
+
+  local timeout = tonumber(arg_timeout) or ( 20 / ( nmap.timing_level() + 1 ) )
+  local results = {}
+  local stime = os.time()
+
+  -- listen until timeout
+  repeat
+    local status, data = socket:receive()
+    if ( status ) then
+      local jenkins_pkt = data:match("^<hudson>(.+)</hudson>")
+      if ( jenkins_pkt ) then
+        local status, _, _, rhost, _ = socket:get_info()
+        local version = jenkins_pkt:match("<version>(.*)</version>")
+        local server_id = jenkins_pkt:match("<server%-id>(.*)</server%-id>")
+        local slave_port = jenkins_pkt:match("<slave%-port>(.*)</slave%-port>")
+        if version and server_id and slave_port then
+          stdnse.print_debug(2, "Received Jenkins discovery response from %s (%s bytes)", rhost, string.len(jenkins_pkt))
+          local str = ("Version: %s; Server ID: %s; Slave Port: %s"):format(version, server_id, slave_port)
+          table.insert( results, str )
+        end
+      end
+    end
+  until( os.time() - stime > timeout )
+  socket:close()
+
+  local response = stdnse.output_table()
+  if #results > 0 then
+    -- remove duplicates
+    local hash = {}
+    for _,v in ipairs(results) do
+      if (not hash[v]) then
+        table.insert( response, v )
+        hash[v] = true
+        if target.ALLOW_NEW_TARGETS then
+          target.add(v)
+        end
+      end
+    end
+    if not target.ALLOW_NEW_TARGETS then
+      response[#response + 1] = "Use --script-args=newtargets to add the results as targets"
+    end
+    return response
+  end
+end

scripts/script.db

@@ -35,6 +35,7 @@ Entry { filename = "broadcast-dropbox-listener.nse", categories = { "broadcast",
 Entry { filename = "broadcast-eigrp-discovery.nse", categories = { "broadcast", "discovery", "safe", } }
 Entry { filename = "broadcast-hid-discoveryd.nse", categories = { "broadcast", "discovery", "safe", } }
 Entry { filename = "broadcast-igmp-discovery.nse", categories = { "broadcast", "discovery", "safe", } }
+Entry { filename = "broadcast-jenkins-discover.nse", categories = { "broadcast", "discovery", "safe", } }
 Entry { filename = "broadcast-listener.nse", categories = { "broadcast", "safe", } }
 Entry { filename = "broadcast-ms-sql-discover.nse", categories = { "broadcast", "safe", } }
 Entry { filename = "broadcast-netbios-master-browser.nse", categories = { "broadcast", "safe", } }