policy-library/policies/templates/gcp_cmek_settings_v1.yaml

# Copyright 2021 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
#
#     https://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-cmek-settings-v1
spec:
  crd:
    spec:
      names:
        kind: GCPCMEKSettingsConstraintV1
      validation:
        openAPIV3Schema:
          properties: {}
  targets:
    validation.gcp.forsetisecurity.org:
      rego: | #INLINE("validator/cmek_settings.rego")
           #
           # Copyright 2021 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.GCPCMEKSettingsConstraintV1

           import data.validator.gcp.lib as lib

           deny[{
           	"msg": message,
           	"details": metadata,
           }] {
           	constraint := input.constraint
           	lib.get_constraint_params(constraint, params)
           	asset := input.asset
           	asset.asset_type == "cloudkms.googleapis.com/CryptoKey"

           	invalid_key_settings(params, asset.resource.data)

           	message := sprintf("%v: CMEK settings are invalid.", [asset.name])
           	metadata := {"resource": asset.name}
           }

           check_protection_level(params, key) = result {
           	not params.protection_level
           	result = true
           }

           check_protection_level(params, key) = result {
           	result = params.protection_level == key.primary.protectionLevel
           }

           check_algorithm(params, key) = result {
           	not params.algorithm
           	result = true
           }

           check_algorithm(params, key) = result {
           	result = params.algorithm == key.primary.algorithm
           }

           check_purpose(params, key) = result {
           	not params.purpose
           	result = true
           }

           check_purpose(params, key) = result {
           	result = params.purpose == key.purpose
           }

           check_rotation_period(params, key) = result {
           	# The rotation period for a key may be "never".  This results
           	# in the rotationPeriod attribute to be omitted from response
           	# from the CAI.  The default is 99999999s.  This is
           	# sufficiently high enough to cause fail
           	rotation_period_string := lib.get_default(key, "rotationPeriod", "99999999s")
           	rotation_period := time.parse_duration_ns(rotation_period_string)

           	period_string := lib.get_default(params, "rotation_period", "31536000s")
           	period_to_test := time.parse_duration_ns(period_string)

           	result = rotation_period <= period_to_test
           }

           invalid_key_settings(params, key) {
           	check_protection_level(params, key) != true
           }

           invalid_key_settings(params, key) {
           	check_rotation_period(params, key) != true
           }

           invalid_key_settings(params, key) {
           	check_algorithm(params, key) != true
           }

           invalid_key_settings(params, key) {
           	check_purpose(params, key) != true
           }
           #ENDINLINE