From dc8e5a5cc7f5e9d1b697e520a7533cc90516db1b Mon Sep 17 00:00:00 2001 From: Dan Smith Date: Mon, 19 Dec 2022 15:00:35 +0000 Subject: [PATCH] Enforce image safety during image_conversion This does two things: 1. It makes us check that the QCOW backing_file is unset on those types of images. Nova and Cinder do this already to prevent an arbitrary (and trivial to accomplish) host file exposure exploit. 2. It makes us restrict VMDK files to only allowed subtypes. These files can name arbitrary files on disk as extents, providing the same sort of attack. Default that list to just the types we believe are actually useful for openstack, and which are monolithic. The configuration option to specify allowed subtypes is added in glance's config and not in the import options so that we can extend this check later to image ingest. The format_inspector can tell us what the type and subtype is, and we could reject those images early and even in the case where image_conversion is not enabled. Closes-Bug: #1996188 Change-Id: Idf561f6306cebf756c787d8eefdc452ce44bd5e0 (cherry picked from commit 0d6282a01691cecc2798f7858b181c4bb30f850c) (cherry picked from commit 4967ab6935cfd0274ae801ac943d01909a236a0a) --- .../async_/flows/plugins/image_conversion.py | 23 +++++++++ glance/common/config.py | 12 +++++ .../flows/plugins/test_image_conversion.py | 47 +++++++++++++++++++ 3 files changed, 82 insertions(+) diff --git a/glance/async_/flows/plugins/image_conversion.py b/glance/async_/flows/plugins/image_conversion.py index b74fea1f3d..f817e80985 100644 --- a/glance/async_/flows/plugins/image_conversion.py +++ b/glance/async_/flows/plugins/image_conversion.py @@ -117,6 +117,29 @@ class _ConvertImage(task.Task): virtual_size = metadata.get('virtual-size', 0) action.set_image_attribute(virtual_size=virtual_size) + if 'backing-filename' in metadata: + LOG.warning('Refusing to process QCOW image with a backing file') + raise RuntimeError( + 'QCOW images with backing files are not allowed') + + if metadata.get('format') == 'vmdk': + create_type = metadata.get( + 'format-specific', {}).get( + 'data', {}).get('create-type') + allowed = CONF.image_format.vmdk_allowed_types + if not create_type: + raise RuntimeError(_('Unable to determine VMDK create-type')) + if not len(allowed): + LOG.warning(_('Refusing to process VMDK file as ' + 'vmdk_allowed_types is empty')) + raise RuntimeError(_('Image is a VMDK, but no VMDK createType ' + 'is specified')) + if create_type not in allowed: + LOG.warning(_('Refusing to process VMDK file with create-type ' + 'of %r which is not in allowed set of: %s'), + create_type, ','.join(allowed)) + raise RuntimeError(_('Invalid VMDK create-type specified')) + if source_format == target_format: LOG.debug("Source is already in target format, " "not doing conversion for %s", self.image_id) diff --git a/glance/common/config.py b/glance/common/config.py index 59091422b2..f161403beb 100644 --- a/glance/common/config.py +++ b/glance/common/config.py @@ -99,6 +99,18 @@ image_format_opts = [ "image attribute"), deprecated_opts=[cfg.DeprecatedOpt('disk_formats', group='DEFAULT')]), + cfg.ListOpt('vmdk_allowed_types', + default=['streamOptimized', 'monolithicSparse'], + help=_("A list of strings describing allowed VMDK " + "'create-type' subformats that will be allowed. " + "This is recommended to only include " + "single-file-with-sparse-header variants to avoid " + "potential host file exposure due to processing named " + "extents. If this list is empty, then no VDMK image " + "types allowed. Note that this is currently only " + "checked during image conversion (if enabled), and " + "limits the types of VMDK images we will convert " + "from.")), ] task_opts = [ cfg.IntOpt('task_time_to_live', diff --git a/glance/tests/unit/async_/flows/plugins/test_image_conversion.py b/glance/tests/unit/async_/flows/plugins/test_image_conversion.py index c5ca29b56a..2056f5b0ef 100644 --- a/glance/tests/unit/async_/flows/plugins/test_image_conversion.py +++ b/glance/tests/unit/async_/flows/plugins/test_image_conversion.py @@ -173,6 +173,53 @@ class TestConvertImageTask(test_utils.BaseTestCase): # Make sure we did not update the image self.img_repo.save.assert_not_called() + def test_image_convert_invalid_qcow(self): + data = {'format': 'qcow2', + 'backing-filename': '/etc/hosts'} + + convert = self._setup_image_convert_info_fail() + with mock.patch.object(processutils, 'execute') as exc_mock: + exc_mock.return_value = json.dumps(data), '' + e = self.assertRaises(RuntimeError, + convert.execute, 'file:///test/path.qcow') + self.assertEqual('QCOW images with backing files are not allowed', + str(e)) + + def _test_image_convert_invalid_vmdk(self): + data = {'format': 'vmdk', + 'format-specific': { + 'data': { + 'create-type': 'monolithicFlat', + }}} + + convert = self._setup_image_convert_info_fail() + with mock.patch.object(processutils, 'execute') as exc_mock: + exc_mock.return_value = json.dumps(data), '' + convert.execute('file:///test/path.vmdk') + + def test_image_convert_invalid_vmdk(self): + e = self.assertRaises(RuntimeError, + self._test_image_convert_invalid_vmdk) + self.assertEqual('Invalid VMDK create-type specified', str(e)) + + def test_image_convert_valid_vmdk_no_types(self): + with mock.patch.object(CONF.image_format, 'vmdk_allowed_types', + new=[]): + # We make it past the VMDK check and fail because our file + # does not exist + e = self.assertRaises(RuntimeError, + self._test_image_convert_invalid_vmdk) + self.assertEqual('Image is a VMDK, but no VMDK createType is ' + 'specified', str(e)) + + def test_image_convert_valid_vmdk(self): + with mock.patch.object(CONF.image_format, 'vmdk_allowed_types', + new=['monolithicSparse', 'monolithicFlat']): + # We make it past the VMDK check and fail because our file + # does not exist + self.assertRaises(FileNotFoundError, + self._test_image_convert_invalid_vmdk) + def test_image_convert_fails(self): convert = self._setup_image_convert_info_fail() with mock.patch.object(processutils, 'execute') as exc_mock: