Support an MSFLOGO env var and logo enumeration

Author: zeroSteiner

data/logos/branded-longhorn.txt renamed to data/logos/cow-branded-longhorn.txt

@@ -8,33 +8,22 @@ module Ui
 #
 ###
 module Banner
-
-  Logos =
-  %w{
-    branded-longhorn.txt
-    cow-head.txt
-    cowsay.txt
-    figlet.txt
-    i-heart-shells.txt
-    metasploit-shield.txt
-    missile-command.txt
-    ninja.txt
-    null-pointer-deref.txt
-    r7-metasploit.txt
-    wake-up-neo.txt
-    workflow.txt
-    3kom-superhack.txt
-    metasploit-park.txt
-  }
-
   #
-  # Returns a random metasploit logo.
+  # Returns a specific metasploit logo. If the specified file is a relative path
+  # then the file will be searched for first in the included local directory,
+  # then in the user-specific directory.
   #
   def self.readfile(fname)
     pathname = fname
+
     unless File.absolute_path(pathname) == pathname
-      pathname = File.join(::Msf::Config.logos_directory, fname)
+      if File.readable?(File.join(::Msf::Config.logos_directory, fname))
+        pathname = File.join(::Msf::Config.logos_directory, fname)
+      elsif File.readable?(File.join(::Msf::Config.user_logos_directory, fname))
+        pathname = File.join(::Msf::Config.user_logos_directory, fname)
+      end
     end
+
     fdata = "<< Missing banner: #{pathname} >>"
     begin
       raise ArgumentError unless File.readable?(pathname)
@@ -47,22 +36,19 @@ def self.readfile(fname)
   end
 
   def self.to_s
+    return self.readfile ENV['MSFLOGO'] if ENV['MSFLOGO']
+
+    logos = []
     # Easter egg (always a cow themed logo): export/set GOCOW=1
     if ENV['GOCOW']
-      case rand(3)
-        when 0
-          # branded-longhorn
-          self.readfile Logos[0]
-        when 1
-          # cow-head
-          self.readfile Logos[1]
-        else
-          # cowsay
-          self.readfile Logos[2]
-        end
+      logos.concat(Dir.glob(::Msf::Config.logos_directory + File::SEPARATOR + 'cow*.txt'))
     else
-      self.readfile Logos[rand(Logos.length)]
+      logos.concat(Dir.glob(::Msf::Config.logos_directory + File::SEPARATOR + '*.txt'))
+      logos.concat(Dir.glob(::Msf::Config.user_logos_directory + File::SEPARATOR + '*.txt'))
     end
+
+    logos = logos.map { |f| File.absolute_path(f) }
+    self.readfile logos[rand(logos.length)]
   end
 end