1 files changed, 78 insertions, 0 deletions
diff --git a/lib/safe.rb b/lib/safe.rb
new file mode 100644
index 0000000000..7c95555495
--- /dev/null
+++ b/lib/safe.rb
@@ -0,0 +1,78 @@
+# this is a safe-mode for ruby, which is still incomplete.
+
+unless defined? SecurityError
+  class SecurityError<Exception
+  end
+end
+
+module Restricted
+
+  printf STDERR, "feel free for some warnings:\n" if $VERBOSE
+  module Bastion
+    include Restricted
+    extend Restricted
+    BINDING = binding
+    def Bastion.to_s; "main" end
+  end
+
+  class R_File<File
+    NG_FILE_OP = []
+    def R_File.open(*args)
+      raise SecurityError, "can't use File.open() in safe mode" #'
+    end
+  end
+
+  IO = nil
+  File = R_File
+  FileTest = nil
+  Dir = nil
+  ObjectSpace = nil
+
+  def eval(string)
+    begin
+      super(string, Bastion::BINDING)
+    rescue
+      $@ = caller
+      raise
+    end
+  end
+  module_function :eval
+
+  DEFAULT_SECURITY_MANAGER = Object.new
+
+  def Restricted.set_securuty_manager(sec_man)
+    if @sec_man
+      raise SecurityError, "cannot change security manager"
+    end
+    @sec_man = sec_man
+  end
+
+  def Restricted.securuty_manager
+    return @sec_man if @sec_man
+    return DEFAULT_SECURITY_MANAGER
+  end
+
+  for cmd in ["test", "require", "load", "open", "system"]
+    eval format("def DEFAULT_SECURITY_MANAGER.%s(*args)
+                   raise SecurityError, \"can't use %s() in safe mode\"
+                 end", cmd, cmd) #'
+    eval format("def %s(*args)
+                   Restricted.securuty_manager.%s(*args)
+                 end", cmd, cmd) 
+  end
+
+  def `(arg) #`
+    Restricted.securuty_manager.send(:`, arg) #`)
+  end
+
+  def DEFAULT_SECURITY_MANAGER.`(arg) #`
+    raise SecurityError, "can't use backquote(``) in safe mode"
+  end
+end
+
+if $DEBUG
+  p eval("File.open('/dev/null')")
+  p Restricted.eval("self")
+  p Restricted.eval("open('/dev/null')")
+  p Restricted.eval("File.open('/dev/null')")
+end