130 lines
4.9 KiB
Python
130 lines
4.9 KiB
Python
# -*- coding: utf-8 -*- #
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# Copyright 2017 Google LLC. All Rights Reserved.
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#
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# Licensed under the Apache License, Version 2.0 (the "License");
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# you may not use this file except in compliance with the License.
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# You may obtain a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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"""Decrypt an input file using an asymmetric-encryption key version."""
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from __future__ import absolute_import
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from __future__ import division
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from __future__ import unicode_literals
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from apitools.base.py import exceptions as apitools_exceptions
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from googlecloudsdk.api_lib.cloudkms import base as cloudkms_base
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from googlecloudsdk.calliope import base
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from googlecloudsdk.calliope import exceptions
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from googlecloudsdk.command_lib.kms import crc32c
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from googlecloudsdk.command_lib.kms import e2e_integrity
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from googlecloudsdk.command_lib.kms import flags
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from googlecloudsdk.core import log
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from googlecloudsdk.core.console import console_io
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from googlecloudsdk.core.util import files
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class AsymmetricDecrypt(base.Command):
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r"""Decrypt an input file using an asymmetric-encryption key version.
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Decrypts the given ciphertext file using the provided asymmetric-encryption
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key version and saves the decrypted data to the plaintext file.
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By default, the command performs integrity verification on data sent to and
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received from Cloud KMS. Use `--skip-integrity-verification` to disable
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integrity verification.
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## EXAMPLES
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The following command will read the file '/tmp/my/secret.file.enc', decrypt it
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using the asymmetric CryptoKey `dont-panic` Version 3 and write the plaintext
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to '/tmp/my/secret.file.dec'.
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$ {command} \
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--location=us-central1 \
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--keyring=hitchhiker \
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--key=dont-panic \
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--version=3 \
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--ciphertext-file=/tmp/my/secret.file.enc \
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--plaintext-file=/tmp/my/secret.file.dec
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"""
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@staticmethod
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def Args(parser):
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flags.AddKeyResourceFlags(parser, 'to use for asymmetric-decryption.')
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flags.AddCryptoKeyVersionFlag(parser, 'to use for asymmetric-decryption')
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flags.AddCiphertextFileFlag(parser, 'to decrypt')
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flags.AddPlaintextFileFlag(parser, 'to output')
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flags.AddSkipIntegrityVerification(parser)
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def _PerformIntegrityVerification(self, args):
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return not args.skip_integrity_verification
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def _CreateAsymmetricDecryptRequest(self, args):
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try:
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ciphertext = console_io.ReadFromFileOrStdin(
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args.ciphertext_file, binary=True)
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except files.Error as e:
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raise exceptions.BadFileException(
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'Failed to read ciphertext file [{0}]: {1}'.format(
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args.ciphertext_file, e))
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messages = cloudkms_base.GetMessagesModule()
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crypto_key_ref = flags.ParseCryptoKeyVersionName(args)
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req = messages.CloudkmsProjectsLocationsKeyRingsCryptoKeysCryptoKeyVersionsAsymmetricDecryptRequest( # pylint: disable=line-too-long
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name=crypto_key_ref.RelativeName())
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if self._PerformIntegrityVerification(args):
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ciphertext_crc32c = crc32c.Crc32c(ciphertext)
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req.asymmetricDecryptRequest = messages.AsymmetricDecryptRequest(
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ciphertext=ciphertext, ciphertextCrc32c=ciphertext_crc32c)
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else:
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req.asymmetricDecryptRequest = messages.AsymmetricDecryptRequest(
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ciphertext=ciphertext)
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return req
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def _VerifyResponseIntegrityFields(self, req, resp):
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"""Verifies integrity fields in response."""
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# ciphertext_crc32c was verified server-side.
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if not resp.verifiedCiphertextCrc32c:
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raise e2e_integrity.ClientSideIntegrityVerificationError(
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e2e_integrity.GetRequestToServerCorruptedErrorMessage())
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# Verify plaintext checksum.
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if not crc32c.Crc32cMatches(resp.plaintext, resp.plaintextCrc32c):
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raise e2e_integrity.ClientSideIntegrityVerificationError(
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e2e_integrity.GetResponseFromServerCorruptedErrorMessage())
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def Run(self, args):
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req = self._CreateAsymmetricDecryptRequest(args)
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client = cloudkms_base.GetClientInstance()
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try:
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resp = (
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client.projects_locations_keyRings_cryptoKeys_cryptoKeyVersions
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.AsymmetricDecrypt(req))
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# Intercept INVALID_ARGUMENT errors related to checksum verification to
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# present a user-friendly message. All other errors are surfaced as-is.
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except apitools_exceptions.HttpBadRequestError as error:
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e2e_integrity.ProcessHttpBadRequestError(error)
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if self._PerformIntegrityVerification(args):
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self._VerifyResponseIntegrityFields(req, resp)
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try:
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log.WriteToFileOrStdout(
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args.plaintext_file,
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resp.plaintext or '',
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overwrite=True,
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binary=True,
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private=True)
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except files.Error as e:
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raise exceptions.BadFileException(e)
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