62 lines
2.1 KiB
Python
62 lines
2.1 KiB
Python
import base64
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import hashlib
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from cryptography.hazmat.backends import default_backend
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from cryptography.hazmat.primitives.ciphers import Cipher
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from cryptography.hazmat.primitives.ciphers.algorithms import AES
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from cryptography.hazmat.primitives.ciphers.modes import ECB
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__all__ = ['get_encryption_key', 'decrypt_field']
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def get_encryption_key(field_name, pk=None):
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'''
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Generate key for encrypted password based on field name,
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``settings.SECRET_KEY``, and instance pk (if available).
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:param pk: (optional) the primary key of the ``awx.conf.model.Setting``;
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can be omitted in situations where you're encrypting a setting
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that is not database-persistent (like a read-only setting)
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'''
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from django.conf import settings
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h = hashlib.sha1()
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h.update(settings.SECRET_KEY)
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if pk is not None:
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h.update(str(pk))
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h.update(field_name)
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return h.digest()[:16]
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def decrypt_value(encryption_key, value):
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raw_data = value[len('$encrypted$'):]
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# If the encrypted string contains a UTF8 marker, discard it
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utf8 = raw_data.startswith('UTF8$')
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if utf8:
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raw_data = raw_data[len('UTF8$'):]
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algo, b64data = raw_data.split('$', 1)
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if algo != 'AES':
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raise ValueError('unsupported algorithm: %s' % algo)
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encrypted = base64.b64decode(b64data)
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decryptor = Cipher(AES(encryption_key), ECB(), default_backend()).decryptor()
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value = decryptor.update(encrypted) + decryptor.finalize()
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value = value.rstrip('\x00')
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# If the encrypted string contained a UTF8 marker, decode the data
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if utf8:
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value = value.decode('utf-8')
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return value
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def decrypt_field(instance, field_name, subfield=None):
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'''
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Return content of the given instance and field name decrypted.
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'''
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value = getattr(instance, field_name)
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if isinstance(value, dict) and subfield is not None:
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value = value[subfield]
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if not value or not value.startswith('$encrypted$'):
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return value
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key = get_encryption_key(field_name, getattr(instance, 'pk', None))
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return decrypt_value(key, value)
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