Disallow python pickle opcodes.

p.pickle

cos
system
(S'/bin/sh'
tR.

p.py

import sys
import pickle
import pickletools

payload = open('p.pickle', 'rb').read()
disallowed = [
    'GLOBAL',
    'REDUCE',
    'INST',
    'OBJ',
    'NEWOBJ'
]

for opcode, arg, pos in pickletools.genops(payload):
    if opcode.name in disallowed:
        print("Detected disallowed opcode: %s" % opcode.name)
        sys.exit(1)

print(pickletools.dis(payload))
pickle.loads(payload)