Python Pickle Issue

Question

We had given a task and for which we written below code, while executing it showing an error. Hence issue in pickle need help for . Please let us know where we went wrong in coding-

import os
import builtins
import pickle
import sys
sys.tracebacklimit=0
import traceback
import io
from logging import Logger

safe_builtins = {
        'range',
        'complex',
        'set',
        'frozenset',
        }

class RestrictedUnpickler(pickle.Unpickler):

      def find_class(self, module, name):
      # Only allow safe classes from builtins.
       if module == "builtins" and name in safe_builtins:
           return getattr(builtins, name)
        # Forbid everything else.
       raise pickle.UnpicklingError("global '%s.%s' is forbidden" %
       (module, name))
    
    def restricted_loads(s):
        """Helper function analogous to pickle.loads()."""
        return RestrictedUnpickler(io.BytesIO(s)).load()
    
    def func1(a): 
      try: 
        x= restricted_loads(pickle.dumps(a))
          return x 
            except pickle.UnpicklingError : 
      s=traceback.format_exc()
         return s
    
    
    def func2(s):
      try:
        x=restricted_loads(pickle.dumps(s))
        return s[x]
      except pickle.UnpicklingError :
 s=traceback.format_exc()
        return s
    
       
    if __name__ == "__main__":
        a=range(int(input())) 
        b=func1(a)
        print(b)
        y=tuple(input())
        z=func2(y)
        print(z)

Getting, we assume issue is with function 2. Where we are not getting correct output. Function 1 is working perfectly seems that why we are getting some output. We had also attach a image for problem statement i.e. what we need to perform in the different function.

Please suggest where we went wrong.

TypeError: tuple indices must be integers or slices, not tuple

Input (stdin)
50 
"a", "b", "c", "d", "e", "f", "g", "h"

Your Output (stdout) 
range(0, 50)

Expected Output 
range(0, 50) 
Traceback (most recent call last): 
_pickle.UnpicklingError: global 'builtins.slice' is forbidden

Why are you (A): importing `builtins` yourself, and (B): making only some properties of it usable? Plus, it might help if you add `slice` to the list of permitted functions in `builtins`. — linux_kettle, Nov 30 '20 at 04:27
Okay, try printing out what `restricted_loads(pickle.dumps(s))` is returning, i.e. `print(x)` on the line below. That might shed more light on the second problem. — linux_kettle, Nov 30 '20 at 04:33
There is no issue with fun1.. main issue is with func2 look like — Ashish Jindal, Nov 30 '20 at 11:03
we tried to print x.....x = ('"', 'a', '"', ',', ' ', '"', 'b', '"', ',', ' ', '"', 'c', '"', ',', ' ', '"', 'd', '"', ',', ' ', '"', 'e', '"', ',', ' ', '"', 'f', '"', ',', ' ', '"', 'g', '"', ',', ' ', '"', 'h', '"') an example — Ashish Jindal, Nov 30 '20 at 11:04
In another input we have ,,,,, ('1', ',', '2', ',', '3', ',', '4', ',', '5') — Ashish Jindal, Nov 30 '20 at 13:03
TypeError: slice indices must be integers or None or have an __index__ method — Ashish Jindal, Nov 30 '20 at 13:49
we did x = slice(0, 8, 3) then there is no error but required output not coming — Ashish Jindal, Nov 30 '20 at 17:38
``` def func2(s): try: x= slice(0, 8, 3) return s[x] except pickle.UnpicklingError : s=traceback.format_exc() return s ``` — Ashish Jindal, Nov 30 '20 at 18:15
Expected Output range(0, 50) Traceback (most recent call last): _pickle.UnpicklingError: global 'builtins.slice' is forbidden — Ashish Jindal, Nov 30 '20 at 18:16

score 1 · Answer 1 · answered Dec 31 '20 at 11:42

1

In the func2, write x=restricted_loads(pickle.dumps(slice(s)))

answered Dec 31 '20 at 11:42

Purva Chaudhari

11
1

Sajid Saifi · Answer 2 · 2021-02-08T06:48:06.870

#frescoplay pickle problem 
import os
import builtins
import pickle
import sys
sys.tracebacklimit=0
import traceback
import io
from logging import Logger

safe_builtins = {
        'range',
        'complex',
        'set',
        'frozenset',
        }

class RestrictedUnpickler(pickle.Unpickler):

   def find_class(self, module, name):
    # Only allow safe classes from builtins.
      if module == "builtins" and name in safe_builtins:
          return getattr(builtins, name)
    # Forbid everything else.
      raise pickle.UnpicklingError("global '%s.%s' is forbidden" %
      (module, name))
        
        

def restricted_loads(s):
        """Helper function analogous to pickle.loads()."""
        return RestrictedUnpickler(io.BytesIO(s)).load()

def func1(a): 
    try: 
        x= restricted_loads(pickle.dumps(a))
        return x 
    except pickle.UnpicklingError : 
        s=traceback.format_exc()
        return s
    
    
def func2(s):
    try:
        x=restricted_loads(pickle.dumps(slice(s)))
        return s[x]
    except pickle.UnpicklingError :
        s=traceback.format_exc()
        return s

    
if __name__ == "__main__":
       a=range(int(input`enter code here`())) 
       b=func1(a)
       print(b)
       y=tuple(input())
       z=func2(y)
       print(z)

Python Pickle Issue

2 Answers2