Merge pull request #128 from kevgliss/fernet_migration
[WIP] Adding aes - fernet migration
This commit is contained in:
kevgliss
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"""Migrates the private key encrypted column from AES to fernet encryption scheme.
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Revision ID: ed422fc58ba
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Revises: 4bcfa2c36623
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Create Date: 2015-10-23 09:19:28.654126
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"""
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import base64
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# revision identifiers, used by Alembic.
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revision = 'ed422fc58ba'
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down_revision = '4bcfa2c36623'
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import six
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from StringIO import StringIO
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from alembic import op
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import sqlalchemy as sa
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from sqlalchemy.sql import text
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from cryptography.hazmat.backends import default_backend
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from cryptography.hazmat.primitives import hashes
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from cryptography.hazmat.primitives.ciphers import Cipher, algorithms, modes
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from cryptography.fernet import Fernet, MultiFernet
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from flask import current_app
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from lemur.common.utils import get_psuedo_random_string
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conn = op.get_bind()
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#op.drop_table('encrypted_keys')
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#op.drop_table('encrypted_passwords')
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# helper tables to migrate data
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temp_key_table = op.create_table('encrypted_keys',
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sa.Column('id', sa.Integer(), nullable=False),
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sa.Column('aes', sa.Binary()),
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sa.Column('fernet', sa.Binary()),
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sa.PrimaryKeyConstraint('id')
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)
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# helper table to migrate data
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temp_password_table = op.create_table('encrypted_passwords',
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sa.Column('id', sa.Integer(), nullable=False),
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sa.Column('aes', sa.Binary()),
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sa.Column('fernet', sa.Binary()),
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sa.PrimaryKeyConstraint('id')
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)
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# From http://sqlalchemy-utils.readthedocs.org/en/latest/_modules/sqlalchemy_utils/types/encrypted.html#EncryptedType
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# for migration purposes only
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class EncryptionDecryptionBaseEngine(object):
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"""A base encryption and decryption engine.
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This class must be sub-classed in order to create
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new engines.
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"""
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def _update_key(self, key):
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if isinstance(key, six.string_types):
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key = key.encode()
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digest = hashes.Hash(hashes.SHA256(), backend=default_backend())
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digest.update(key)
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engine_key = digest.finalize()
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self._initialize_engine(engine_key)
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def encrypt(self, value):
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raise NotImplementedError('Subclasses must implement this!')
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def decrypt(self, value):
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raise NotImplementedError('Subclasses must implement this!')
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class AesEngine(EncryptionDecryptionBaseEngine):
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"""Provide AES encryption and decryption methods."""
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BLOCK_SIZE = 16
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PADDING = six.b('*')
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def _initialize_engine(self, parent_class_key):
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self.secret_key = parent_class_key
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self.iv = self.secret_key[:16]
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self.cipher = Cipher(
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algorithms.AES(self.secret_key),
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modes.CBC(self.iv),
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backend=default_backend()
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)
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def _pad(self, value):
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"""Pad the message to be encrypted, if needed."""
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BS = self.BLOCK_SIZE
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P = self.PADDING
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padded = (value + (BS - len(value) % BS) * P)
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return padded
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def encrypt(self, value):
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if not isinstance(value, six.string_types):
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value = repr(value)
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if isinstance(value, six.text_type):
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value = str(value)
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value = value.encode()
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value = self._pad(value)
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encryptor = self.cipher.encryptor()
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encrypted = encryptor.update(value) + encryptor.finalize()
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encrypted = base64.b64encode(encrypted)
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return encrypted
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def decrypt(self, value):
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if isinstance(value, six.text_type):
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value = str(value)
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decryptor = self.cipher.decryptor()
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decrypted = base64.b64decode(value)
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decrypted = decryptor.update(decrypted) + decryptor.finalize()
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decrypted = decrypted.rstrip(self.PADDING)
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if not isinstance(decrypted, six.string_types):
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decrypted = decrypted.decode('utf-8')
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return decrypted
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def migrate_to_fernet(aes_encrypted, old_key, new_key):
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"""
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Will attempt to migrate an aes encrypted to fernet encryption
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:param aes_encrypted:
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:return: fernet encrypted value
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"""
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engine = AesEngine()
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engine._update_key(old_key)
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if not isinstance(aes_encrypted, six.string_types):
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return
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aes_decrypted = engine.decrypt(aes_encrypted)
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fernet_encrypted = MultiFernet([Fernet(k) for k in new_key]).encrypt(bytes(aes_decrypted))
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# sanity check
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fernet_decrypted = MultiFernet([Fernet(k) for k in new_key]).decrypt(fernet_encrypted)
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if fernet_decrypted != aes_decrypted:
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raise Exception("WARNING: Decrypted values do not match!")
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return fernet_encrypted
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def migrate_from_fernet(fernet_encrypted, old_key, new_key):
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"""
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Will attempt to migrate from a fernet encryption to aes
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:param fernet_encrypted:
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:return:
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"""
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engine = AesEngine()
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engine._update_key(new_key)
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fernet_decrypted = MultiFernet([Fernet(k) for k in old_key]).decrypt(fernet_encrypted)
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aes_encrypted = engine.encrypt(fernet_decrypted)
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# sanity check
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aes_decrypted = engine.decrypt(aes_encrypted)
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if fernet_decrypted != aes_decrypted:
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raise Exception("WARNING: Decrypted values do not match!")
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return aes_encrypted
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def upgrade():
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old_key = current_app.config.get('LEMUR_ENCRYPTION_KEY')
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print "Using: {0} as decryption key".format(old_key)
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# generate a new fernet token
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if current_app.config.get('LEMUR_ENCRYPTION_KEYS'):
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new_key = current_app.config.get('LEMUR_ENCRYPTION_KEYS')
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else:
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new_key = [Fernet.generate_key()]
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print "Using: {0} as new encryption key, save this and place it in your configuration!".format(new_key)
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# migrate private_keys
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temp_keys = []
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for id, private_key in conn.execute(text('select id, private_key from certificates where private_key is not null')):
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aes_encrypted = StringIO(private_key).read()
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fernet_encrypted = migrate_to_fernet(aes_encrypted, old_key, new_key)
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temp_keys.append({'id': id, 'aes': aes_encrypted, 'fernet': fernet_encrypted})
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op.bulk_insert(temp_key_table, temp_keys)
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for id, fernet in conn.execute(text('select id, fernet from encrypted_keys')):
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stmt = text("update certificates set private_key=:key where id=:id")
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stmt = stmt.bindparams(key=fernet, id=id)
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op.execute(stmt)
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print "Certificate {0} has been migrated".format(id)
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# migrate role_passwords
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temp_passwords = []
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for id, password in conn.execute(text('select id, password from roles where password is not null')):
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aes_encrypted = StringIO(password).read()
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fernet_encrypted = migrate_to_fernet(aes_encrypted, old_key, new_key)
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temp_passwords.append({'id': id, 'aes': aes_encrypted, 'fernet': fernet_encrypted})
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op.bulk_insert(temp_password_table, temp_passwords)
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for id, fernet in conn.execute(text('select id, fernet from encrypted_passwords')):
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stmt = text("update roles set password=:password where id=:id")
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stmt = stmt.bindparams(password=fernet, id=id)
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print stmt
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op.execute(stmt)
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print "Password {0} has been migrated".format(id)
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op.drop_table('encrypted_keys')
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op.drop_table('encrypted_passwords')
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def downgrade():
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old_key = current_app.config.get('LEMUR_ENCRYPTION_KEYS')
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print "Using: {0} as decryption key(s)".format(old_key)
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# generate aes valid key
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if current_app.config.get('LEMUR_ENCRYPTION_KEY'):
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new_key = current_app.config.get('LEMUR_ENCRYPTION_KEY')
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else:
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new_key = get_psuedo_random_string()
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print "Using: {0} as the encryption key, save this and place it in your configuration!".format(new_key)
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# migrate keys
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temp_keys = []
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for id, private_key in conn.execute(text('select id, private_key from certificates where private_key is not null')):
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fernet_encrypted = StringIO(private_key).read()
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aes_encrypted = migrate_from_fernet(fernet_encrypted, old_key, new_key)
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temp_keys.append({'id': id, 'aes': aes_encrypted, 'fernet': fernet_encrypted})
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op.bulk_insert(temp_key_table, temp_keys)
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for id, aes in conn.execute(text('select id, aes from encrypted_keys')):
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stmt = text("update certificates set private_key=:key where id=:id")
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stmt = stmt.bindparams(key=aes, id=id)
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print stmt
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op.execute(stmt)
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print "Certificate {0} has been migrated".format(id)
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# migrate role_passwords
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temp_passwords = []
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for id, password in conn.execute(text('select id, password from roles where password is not null')):
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fernet_encrypted = StringIO(password).read()
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aes_encrypted = migrate_from_fernet(fernet_encrypted, old_key, new_key)
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temp_passwords.append({'id': id, 'aes': aes_encrypted, 'fernet': fernet_encrypted})
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op.bulk_insert(temp_password_table, temp_passwords)
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for id, aes in conn.execute(text('select id, aes from encrypted_passwords')):
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stmt = text("update roles set password=:password where id=:id")
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stmt = stmt.bindparams(password=aes, id=id)
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op.execute(stmt)
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print "Password {0} has been migrated".format(id)
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op.drop_table('encrypted_keys')
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op.drop_table('encrypted_passwords')
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