Move image verification and writing out of download method
This should help the readability and also make it possible to call new _verify_and_write method with different arguments. Change-Id: I20913201cf945a7fde1f9e6264c415e1235db7b9
This commit is contained in:
Jiří Suchomel
parent
d4c857dfcb
commit
ccfde2795a
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@ -326,59 +326,88 @@ class GlanceImageServiceV2(object):
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raise exception.ImageUnacceptable(image_id=image_id,
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reason='Image has no associated data')
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# Retrieve properties for verification of Glance image signature
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verifier = self._get_verifier(context, image_id, trusted_certs)
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return self._verify_and_write(context, image_id, trusted_certs,
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image_chunks, data, dst_path)
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def _verify_and_write(self, context, image_id, trusted_certs,
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image_chunks, data, dst_path):
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"""Perform image signature verification and save the image file if needed.
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This function writes the content of the image_chunks iterator either to
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a file object provided by the data parameter or to a filepath provided
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by dst_path parameter. If none of them are provided then no data will
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be written out but instead image_chunks iterator is returned.
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:param image_id: The UUID of the image
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:param trusted_certs: A 'nova.objects.trusted_certs.TrustedCerts'
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object with a list of trusted image certificate
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IDs.
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:param image_chunks An iterator pointing to the image data
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:param data: File object to use when writing the image.
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If passed as None and dst_path is provided, new file is opened.
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:param dst_path: Filepath to transfer the image file to.
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:returns an iterable with image data, or nothing. Iterable is returned
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only when data param is None and dst_path is not provided (assuming
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the caller wants to process the data by itself).
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"""
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close_file = False
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if data is None and dst_path:
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data = open(dst_path, 'wb')
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close_file = True
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write_image = True
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if data is None:
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write_image = False
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# Perform image signature verification
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if verifier:
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try:
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for chunk in image_chunks:
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verifier.update(chunk)
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verifier.verify()
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# Retrieve properties for verification of Glance image signature
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verifier = self._get_verifier(context, image_id, trusted_certs)
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LOG.info('Image signature verification succeeded '
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'for image: %s', image_id)
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# Exit early if we do not need write nor verify
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if verifier is None and write_image is False:
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if data is None:
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return image_chunks
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else:
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return
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except cryptography.exceptions.InvalidSignature:
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with excutils.save_and_reraise_exception():
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LOG.error('Image signature verification failed '
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'for image: %s', image_id)
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return image_chunks
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else:
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try:
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for chunk in image_chunks:
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if verifier:
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verifier.update(chunk)
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data.write(chunk)
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try:
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for chunk in image_chunks:
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if verifier:
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verifier.verify()
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LOG.info('Image signature verification succeeded '
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'for image %s', image_id)
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except cryptography.exceptions.InvalidSignature:
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verifier.update(chunk)
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if write_image:
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data.write(chunk)
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if verifier:
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verifier.verify()
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LOG.info('Image signature verification succeeded '
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'for image %s', image_id)
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except cryptography.exceptions.InvalidSignature:
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if write_image:
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data.truncate(0)
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with excutils.save_and_reraise_exception():
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LOG.error('Image signature verification failed '
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'for image: %s', image_id)
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except Exception as ex:
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with excutils.save_and_reraise_exception():
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LOG.error('Image signature verification failed '
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'for image %s', image_id)
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except Exception as ex:
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if write_image:
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with excutils.save_and_reraise_exception():
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LOG.error("Error writing to %(path)s: %(exception)s",
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{'path': dst_path, 'exception': ex})
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finally:
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if close_file:
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# Ensure that the data is pushed all the way down to
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# persistent storage. This ensures that in the event of a
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# subsequent host crash we don't have running instances
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# using a corrupt backing file.
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data.flush()
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self._safe_fsync(data)
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data.close()
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else:
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with excutils.save_and_reraise_exception():
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LOG.error("Error during image verification: %s", ex)
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finally:
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if close_file:
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# Ensure that the data is pushed all the way down to
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# persistent storage. This ensures that in the event of a
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# subsequent host crash we don't have running instances
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# using a corrupt backing file.
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data.flush()
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self._safe_fsync(data)
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data.close()
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if data is None:
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return image_chunks
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def _get_verifier(self, context, image_id, trusted_certs):
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verifier = None
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@ -884,7 +884,7 @@ class TestDownloadSignatureVerification(test.NoDBTestCase):
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'trusted image certificate IDs must be provided in '
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'order to validate an image certificate.')
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mock_log.debug.assert_called_once_with(msg)
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msg = ('Image signature verification succeeded for image: %s')
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msg = ('Image signature verification succeeded for image %s')
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mock_log.info.assert_called_once_with(msg, image_id)
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@mock.patch.object(six.moves.builtins, 'open')
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