mirror of
https://github.com/avatao-content/baseimage-tutorial-framework
synced 2024-11-15 04:17:16 +00:00
72 lines
2.0 KiB
Python
72 lines
2.0 KiB
Python
from functools import wraps
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from base64 import b64encode, b64decode
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from copy import deepcopy
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from cryptography.hazmat.backends import default_backend
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from cryptography.hazmat.primitives.hashes import SHA256
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from cryptography.hazmat.primitives.hmac import HMAC as _HMAC
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from cryptography.exceptions import InvalidSignature
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from tfw.internals.networking import message_bytes
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def sign_message(key, message):
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message.pop('scope', None)
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message.pop('signature', None)
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signature = message_signature(key, message)
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message['signature'] = b64encode(signature).decode()
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def message_signature(key, message):
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return HMAC(key, message_bytes(message)).signature
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def verify_message(key, message):
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message.pop('scope', None)
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message = deepcopy(message)
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try:
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signature_b64 = message.pop('signature')
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signature = b64decode(signature_b64)
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actual_signature = message_signature(key, message)
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return signature == actual_signature
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except KeyError:
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return False
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class HMAC:
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def __init__(self, key, message):
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self.key = key
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self.message = message
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self._hmac = _HMAC(
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key=key,
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algorithm=SHA256(),
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backend=default_backend()
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)
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def _reload_if_finalized(f):
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# pylint: disable=no-self-argument,not-callable
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@wraps(f)
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def wrapped(instance, *args, **kwargs):
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if getattr(instance, '_finalized', False):
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instance.__init__(instance.key, instance.message)
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ret_val = f(instance, *args, **kwargs)
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setattr(instance, '_finalized', True)
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return ret_val
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return wrapped
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@property
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@_reload_if_finalized
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def signature(self):
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self._hmac.update(self.message)
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signature = self._hmac.finalize()
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return signature
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@_reload_if_finalized
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def verify(self, signature):
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self._hmac.update(self.message)
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try:
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self._hmac.verify(signature)
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return True
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except InvalidSignature:
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return False
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