Add a module_flavors method for all available flavors

lib/msf/core/exploit/cmdstager.rb

@@ -44,21 +44,10 @@ module Exploit::CmdStager
   def initialize(info = {})
     super
 
-    flavors = []
+    flavors = module_flavors
-    if module_info['CmdStagerFlavor']
+    flavors = STAGERS.keys if flavors.empty?
-      flavors = Array(module_info['CmdStagerFlavor'])
-    else
-      targets.each do |target|
-        flavors += Array(target.opts['CmdStagerFlavor']) if target.opts['CmdStagerFlavor']
-      end
-      flavors.uniq!
-    end
-
-    if flavors.empty?
-      flavors = STAGERS.keys
-    end
-    flavors = flavors.map { |flavor| flavor.to_s }
     flavors.unshift('auto')
+
     register_advanced_options(
       [
         OptEnum.new('CMDSTAGER::FLAVOR', [false, 'The CMD Stager to use.', 'auto', flavors]),
@@ -261,6 +250,20 @@ module Exploit::CmdStager
     end
   end
 
+  # Returns all the compatible stager flavors specified by the module and each
+  # of it's targets.
+  #
+  # @return [Array] the list of all compatible cmd stager flavors.
+  def module_flavors
+    flavors = []
+    flavors += Array(module_info['CmdStagerFlavor']) if module_info['CmdStagerFlavor']
+    targets.each do |target|
+      flavors += Array(target.opts['CmdStagerFlavor']) if target.opts['CmdStagerFlavor']
+    end
+    flavors.uniq!
+    flavors.map { |flavor| flavor.to_s }
+  end
+
   # Returns the compatible stager flavors for the current target or module.
   #
   # @return [Array] the list of compatible cmd stager flavors.