[pybot-commits] CVS: pybot/pybot/modules eval.py,1.5,1.6

[Gustavo N. <nie...@us...>]

Update of /cvsroot/pybot/pybot/pybot/modules
In directory sc8-pr-cvs1:/tmp/cvs-serv29720/pybot/modules

Modified Files:
	eval.py 
Log Message:
* modules/eval.py: Implemented a forking/timeout scheme to
  protect against DoS evaluations. Now it should be possible
  to give wider access to the module.


Index: eval.py
===================================================================
RCS file: /cvsroot/pybot/pybot/pybot/modules/eval.py,v
retrieving revision 1.5
retrieving revision 1.6
diff -C2 -d -r1.5 -r1.6
*** eval.py	24 Aug 2003 19:30:53 -0000	1.5
--- eval.py	29 Aug 2003 00:38:56 -0000	1.6
***************
*** 18,22 ****
--- 18,26 ----
  
  from pybot.locals import *
+ import thread
+ import signal
+ import time
  import math
+ import os
  
  HELP = """
***************
*** 38,41 ****
--- 42,47 ----
  """
  
+ TIMEOUT = 3
+ 
  class Eval:
      def __init__(self):
***************
*** 47,69 ****
          del self.dict["__file__"]
          del self.dict["__name__"]
!         self.dict["map"] = map
!         self.dict["zip"] = zip
!         self.dict["len"] = len
!         self.dict["min"] = min
!         self.dict["max"] = max
!         self.dict["chr"] = chr
!         self.dict["ord"] = ord
          self.dict["abs"] = abs
          self.dict["hex"] = hex
          self.dict["int"] = int
!         self.dict["oct"] = oct
          self.dict["list"] = list
          self.dict["long"] = long
!         self.dict["float"] = float
          self.dict["round"] = round
          self.dict["tuple"] = tuple
!         self.dict["reduce"] = reduce
!         self.dict["filter"] = filter
!         self.dict["coerce"] = coerce
  
          # Match 'eval <expr>'
--- 53,91 ----
          del self.dict["__file__"]
          del self.dict["__name__"]
!         self.dict["False"] = False
!         self.dict["True"] = True
          self.dict["abs"] = abs
+         self.dict["bool"] = bool
+         self.dict["chr"] = chr
+         self.dict["cmp"] = cmp
+         self.dict["coerce"] = coerce
+         self.dict["complex"] = complex
+         self.dict["dict"] = dict
+         self.dict["divmod"] = divmod
+         self.dict["filter"] = filter
+         self.dict["float"] = float
+         self.dict["hash"] = hash
          self.dict["hex"] = hex
+         self.dict["id"] = id
          self.dict["int"] = int
!         self.dict["len"] = len
          self.dict["list"] = list
          self.dict["long"] = long
!         self.dict["map"] = map
!         self.dict["max"] = max
!         self.dict["min"] = min
!         self.dict["oct"] = oct
!         self.dict["ord"] = ord
!         self.dict["pow"] = pow
!         self.dict["range"] = range
!         self.dict["reduce"] = reduce
!         self.dict["repr"] = repr
          self.dict["round"] = round
+         self.dict["str"] = round
          self.dict["tuple"] = tuple
!         self.dict["unichr"] = unichr
!         self.dict["unicode"] = unicode
!         self.dict["xrange"] = range
!         self.dict["zip"] = zip
  
          # Match 'eval <expr>'
***************
*** 79,83 ****
          mm.unregister_help(HELP)
          mm.unregister_perm("eval")
!     
      def message(self, msg):
          if not msg.forme:
--- 101,167 ----
          mm.unregister_help(HELP)
          mm.unregister_perm("eval")
! 
!     def fork_eval(self, expr):
!         try:
!             code = compile(expr, "<string>", "eval")
!         except:
!             return None
!         r, w = os.pipe()
!         pid = os.fork()
!         if pid == 0:
!             os.close(r)
!             fw = os.fdopen(w, "w")
!             try:
!                 fw.write(str(eval(code, self.dict)))
!             except:
!                 pass
!             fw.close()
!             os._exit(1)
!         os.close(w)
!         fr = os.fdopen(r, "r")
!         answer = None
!         timeout = TIMEOUT
!         while 1:
!             try:
!                 _pid, status = os.waitpid(pid, os.WNOHANG)
!             except os.error:
!                 os.kill(pid, signal.SIGKILL)
!                 time.sleep(0.5)
!                 try:
!                     os.waitpid(pid, os.WNOHANG)
!                 except os.error:
!                     pass
!                 break
!             if pid == _pid:
!                 answer = fr.read()
!                 break
!             else:
!                 timeout -= 1
!                 if not timeout:
!                     answer = ["Couldn't wait for your answer.",
!                               "Processing your answer took too long.",
!                               "I'm in a hurry and can't wait for "
!                               "your answer."]
!                     os.kill(pid, signal.SIGKILL)
!                     time.sleep(0.5)
!                     try:
!                         os.waitpid(pid, os.WNOHANG)
!                     except os.error:
!                         pass
!                     break
!                 time.sleep(1)
!         return answer
! 
!     def eval(self, msg, expr):
!         answer = self.fork_eval(expr)
!         if not answer:
!             msg.answer("%:", ["Can't evaluate this",
!                               "There's something wrong with this "
!                               "expression"], [".", "!"])
!         elif len(answer) > 255:
!             msg.answer("%:", "Your answer is too long", [".", "!"])
!         else:
!             msg.answer("%:", answer)
! 
      def message(self, msg):
          if not msg.forme:
***************
*** 87,101 ****
          if m:
              if mm.hasperm(msg, "eval"):
!                 try:
!                     answer = str(eval(m.group("expr"), self.dict))
!                 except:
!                     msg.answer("%:", ["Can't evaluate this",
!                                       "There's something wrong with this "
!                                       "expression"], [".", "!"])
!                 else:
!                     if len(answer) > 255:
!                         msg.answer("%:", "Sorry, your answer is too long...")
!                     else:
!                         msg.answer("%:", str(answer))
              else:
                  msg.answer("%:", ["Sorry...", "Oops!"],
--- 171,175 ----
          if m:
              if mm.hasperm(msg, "eval"):
!                 thread.start_new_thread(self.eval, (msg, m.group("expr")))
              else:
                  msg.answer("%:", ["Sorry...", "Oops!"],