gcp_lb_forwarding_rules.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.
#
apiVersion: templates.gatekeeper.sh/v1alpha1
kind: ConstraintTemplate
metadata:
  name: gcp-lb-allowed-forwarding-rules-v2
  annotations:
    description: "Constraint to restrict forwarding rules based on a allowlist"
spec:
  crd:
    spec:
      names:
        kind: GCPLBAllowedForwardingRulesConstraintV2
      validation:
        openAPIV3Schema:
          properties:
            allowlist:
              type: array
              items:
                type: object
                properties:
                  target:
                    type: string
                  ip_address:
                    type: string
                  ip_protocol:
                    type: string
                  port_range:
                    type: string
                  load_balancing_scheme:
                    type: string
                required:
                  - target
  targets:
    validation.gcp.forsetisecurity.org:
      rego: | #INLINE("validator/gcp_lb_forwarding_rules.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.GCPLBAllowedForwardingRulesConstraintV2
           
           import data.validator.gcp.lib as lib
           
           ###########################
           # Find allowlist Violations
           ###########################
           deny[{
           	"msg": message,
           	"details": metadata,
           }] {
           	constraint := input.constraint
           	lib.get_constraint_params(constraint, params)
           	asset := input.asset
           
           	is_forwarding_rule(asset.asset_type)
           
           	instance := asset.resource.data
           
           	rule := get_allowlist_entry(params.allowlist, instance.target)
           	rule
           
           	invalid_forwarding_rule(rule, instance)
           
           	message := sprintf("%v is not allowed, violates allowlist policy.", [asset.name])
           	metadata := {"resource": asset.name}
           }
           
           ###########################
           # Rule Utilities
           ###########################
           
           is_forwarding_rule(asset_type) {
           	asset_type == "compute.googleapis.com/ForwardingRule"
           }
           
           is_forwarding_rule(asset_type) {
           	asset_type == "compute.googleapis.com/GlobalForwardingRule"
           }
           
           get_allowlist_entry(allowlist, target) = output {
           	rule := allowlist[_]
           	rule.target == target
           	output = rule
           }
           
           check_scheme(rule, resource) {
           	rule.load_balancing_scheme
           	rule.load_balancing_scheme == resource.loadBalancingScheme
           }
           
           check_scheme(rule, resource) {
           	not rule.load_balancing_scheme
           }
           
           check_ip_protocol(rule, resource) {
           	rule.ip_protocol
           	rule.ip_protocol == resource.IPProtocol
           }
           
           check_ip_protocol(rule, resource) {
           	not rule.ip_protocol
           }
           
           check_ip_address(rule, resource) {
           	rule.ip_address
           	rule.ip_address == resource.IPAddress
           }
           
           check_ip_address(rule, resource) {
           	not rule.ip_address
           }
           
           check_port_range(rule, resource) {
           	rule.port_range
           	rule.port_range == resource.portRange
           }
           
           check_port_range(rule, resource) {
           	not rule.port_range
           }
           
           invalid_forwarding_rule(rule, resource) {
           	not check_scheme(rule, resource)
           }
           
           invalid_forwarding_rule(rule, resource) {
           	not check_ip_address(rule, resource)
           }
           
           invalid_forwarding_rule(rule, resource) {
           	not check_ip_protocol(rule, resource)
           }
           
           invalid_forwarding_rule(rule, resource) {
           	not check_port_range(rule, resource)
           }
           #ENDINLINE