gcp_storage_bucket_policy_only_v1.yaml

# Copyright 2019 Google LLC
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#      http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
#

# This template ensures Bucket Policy Only is enabled.
# Bucket Policy Only feature allows you to uniformly control access to 
# Cloud Storage resources. When enabled on a bucket, only bucket-level 
# Cloud IAM permissions grant access to that bucket and the objects it 
# contains; Access Control Lists (ACLs) are disabled and access granted 
# by ACLs is revoked.
# For more details see https://cloud.google.com/storage/docs/bucket-policy-only

apiVersion: templates.gatekeeper.sh/v1alpha1
kind: ConstraintTemplate
metadata:
  name: gcp-storage-bucket-policy-only-v1
spec:
  crd:
    spec:
      names:
        kind: GCPStorageBucketPolicyOnlyConstraintV1
      validation:
        openAPIV3Schema:
          properties: {}
  targets:
   validation.gcp.forsetisecurity.org:
      rego: | #INLINE("validator/storage_bucket_policy_only.rego")
           #
           # Copyright 2018 Google LLC
           #
           # Licensed under the Apache License, Version 2.0 (the "License");
           # you may not use this file except in compliance with the License.
           # You may obtain a copy of the License at
           #
           #      http://www.apache.org/licenses/LICENSE-2.0
           #
           # Unless required by applicable law or agreed to in writing, software
           # distributed under the License is distributed on an "AS IS" BASIS,
           # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
           # See the License for the specific language governing permissions and
           # limitations under the License.
           #
           
           package templates.gcp.GCPStorageBucketPolicyOnlyConstraintV1
           
           import data.validator.gcp.lib as lib
           
           deny[{
           	"msg": message,
           	"details": metadata,
           }] {
           	constraint := input.constraint
           	asset := input.asset
           	asset.asset_type == "storage.googleapis.com/Bucket"
           
           	bucket := asset.resource.data
           	bucket_policy_enabled(bucket) != true
           	uniform_bucket_level_access_enabled(bucket) != true
           
           	message := sprintf("%v does not have bucket policy only enabled.", [asset.name])
           	metadata := {"resource": asset.name}
           }
           
           ###########################
           # Rule Utilities
           ###########################
           bucket_policy_enabled(bucket) = bucket_policy_enabled {
           	iam_configuration := lib.get_default(bucket, "iamConfiguration", {})
           	bucket_policy_only := lib.get_default(iam_configuration, "bucketPolicyOnly", {})
           	bucket_policy_enabled := lib.get_default(bucket_policy_only, "enabled", null)
           }
           
           uniform_bucket_level_access_enabled(bucket) = uniform_bucket_level_access_enabled {
           	iam_configuration := lib.get_default(bucket, "iamConfiguration", {})
           	uniform_bucket_level_access := lib.get_default(iam_configuration, "uniformBucketLevelAccess", {})
           	uniform_bucket_level_access_enabled := lib.get_default(uniform_bucket_level_access, "enabled", null)
           }
           #ENDINLINE