gcp_storage_bucket_world_readable_v1.yaml

# Copyright 2020 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.
#
apiVersion: templates.gatekeeper.sh/v1alpha1
kind: ConstraintTemplate
metadata:
  name: gcp-storage-bucket-world-readable-v1
spec:
  crd:
    spec:
      names:
        kind: GCPStorageBucketWorldReadableConstraintV1
      validation:
        openAPIV3Schema:
          properties:
            exemptions:
              type: array
              items:
                type: string
              description: "Array of GCS buckets to exempt from scanning.
              String values in the array should correspond to the full name
              values of exempted GCS buckets.
              E.g.'//storage.googleapis.com/my-bucket'."
  targets:
   validation.gcp.forsetisecurity.org:
      rego: | #INLINE("validator/storage_bucket_world_readable.rego")
           #
           # Copyright 2020 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.GCPStorageBucketWorldReadableConstraintV1
           
           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"
           
           	# Check if resource is in exempt list
           	check_for_exemptions(asset.name, constraint)
           
           	world_readable_checks := [
           		asset.iam_policy.bindings[_].members[_] == "allUsers",
           		asset.iam_policy.bindings[_].members[_] == "allAuthenticatedUsers",
           	]
           
           	world_readable_checks[_] == true
           
           	message := sprintf("%v is publicly accessible", [asset.name])
           	metadata := {"resource": asset.name}
           }
           
           ###########################
           # Rule Utilities
           ###########################
           
           check_for_exemptions(asset_name, constraint) {
           	lib.get_constraint_params(constraint, params)
           	exempt_list := params.exemptions
           	matches := {asset_name} & cast_set(exempt_list)
           	count(matches) == 0
           }
           
           check_for_exemptions(asset_name, constraint) {
           	lib.has_field(constraint.spec.parameters, "exemptions") == false
           }
           #ENDINLINE