What if, say, you want to disable certain features from core Python? Suppose you ask freshmen to implement "pow" manually. Nothing stops them from using builtin pow, until now.
Install with pip by:
pip install yoink_builtin
import yoink_builtin
import traceback
foo = yoink_builtin.yoink_type_slot(int, 'nb_power')
# Or alternatively, as an example, yoinking a builtin function,
# but ** operator is still callable:
# foo = yoink_builtin.yoink_function(pow)
# You also need to, if there are method wrappers:
# yoink_builtin.yoink_function(int.__pow__)
# yoink_builtin.yoink_function(int.__rpow__)
yoink_builtin.lockdown()
def unsafe_code():
print("Because of yoink, you can't use this:")
try:
print(pow(1, 1))
except Exception:
traceback.print_exc()
print("\nBecause of lockdown, you can't unyoink:")
try:
yoink_builtin.unyoink(foo)
except Exception:
traceback.print_exc()
print("\nAnd you can't even unlockdown:")
try:
yoink_builtin.unlockdown()
except Exception:
traceback.print_exc()
unsafe_code()
print('\nBut I can:')
yoink_builtin.unlockdown()
yoink_builtin.unyoink(foo)
print(pow(1, 1))
print('ayyy success')Should show something similar to:
Because of yoink, you can't use this:
Traceback (most recent call last):
File "test.py", line 18, in unsafe_code
print(pow(1, 1))
NotImplementedError: function has been yoinked
Because of lockdown, you can't unyoink:
Traceback (most recent call last):
File "test.py", line 24, in unsafe_code
yoink_builtin.unyoink(foo)
RuntimeError: lockdown
And you can't even unlockdown:
Traceback (most recent call last):
File "test.py", line 30, in unsafe_code
yoink_builtin.unlockdown()
RuntimeError: bad frame; call unlockdown from same frame as lockdown
But I can:
1
ayyy success
Note: This cannot stop people from messing with CPython internals with ctypes or bytecode constructor and get the 'unyoinking' anyways. Make sure to add audit hooks and sandbox the whole environment before running potentially unsafe code.
Copyright (C) 2022 YiFei Zhu
The right is granted to copy, use, modify and redistribute this code according to the rules in what is commonly referred to as an MIT license.