---
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#  Licensed under the Apache License, Version 2.0 (the "License"). You may not use this file except in compliance
#  with the License. A copy of the License is located at
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#      http://www.apache.org/licenses/LICENSE-2.0
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#  or in the 'license' file accompanying this file. This file is distributed on an 'AS IS' BASIS, WITHOUT WARRANTIES
#  OR CONDITIONS OF ANY KIND, express or implied. See the License for the specific language governing permissions
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AWSTemplateFormatVersion: '2010-09-09'
Transform: AWS::Serverless-2016-10-31

Description: CDF Certificate Vendor Service

Parameters:
  ApplicationConfigurationOverride:
    Description: This allows you to override any application configuration.  It should consists of a text-based content with a structure and syntax comprising key–value pairs for properties. Any configurations contained in this will override the configurations found and merged from the default .env files.
    Type: String
  Environment:
    Description: Name of environment.  Used to name the created resources.
    Type: String
    MinLength: 1
  BucketName:
    Description: Name of bucket of where certificates are stored.
    Type: String
    MinLength: 1
  MQTTGetTopic:
    Description: The MQTT topic where certificate requests are published by a device.
    Default: cdf/certificates/+/get
    Type: String
  MQTTAckTopic:
    Description: The MQTT topic where certificate acknowledgements are published by a device.
    Default: cdf/certificates/+/ack
    Type: String
  ThingGroupName:
    Description: Thing Group of devices requiring certification rotation
    Type: String
    Default: cdfRotateCertificates
  KmsKeyId:
    Description: The KMS key ID used to encrypt SSM parameters
    Type: String
  OpenSslLambdaLayerArn:
    Description: OpenSSL lambda layer ARN
    Type: String
    MinLength: 1
  AssetLibraryFunctionName:
    Description: AssetLibrary REST Api function name
    Type: String
    Default: ''
  CommandsFunctionName:
    Description: Commands REST Api function name
    Type: String
  CustomResourceLambdaArn:
    Description: Custom resource lambda arn
    Type: String
    MinLength: 1
  CaCertificateId:
    Type: String
    Default: ''
  RotatedCertificatePolicy:
    Type: String
    Default: ''

Conditions:
  ThingGroupNameProvided: !Not [!Equals [!Ref ThingGroupName, '']]
  KmsKeyProvided: !Not [!Equals [!Ref KmsKeyId, '']]
  KmsKeyNotProvided: !Equals [!Ref KmsKeyId, '']

Resources:
  MQTTGetRule:
    Type: 'AWS::IoT::TopicRule'
    Properties:
      TopicRulePayload:
        Actions:
          - Lambda:
              FunctionArn: !Sub 'arn:aws:lambda:${AWS::Region}:${AWS::AccountId}:function:${LambdaFunction}'
        Description: 'Certificate requests (CDF Certificate Vendor service)'
        AwsIotSqlVersion: '2016-03-23'
        RuleDisabled: false
        Sql: !Sub "SELECT topic(3) as deviceId, topic(4) as action, principal() as certId, * FROM '${MQTTGetTopic}'"

  MQTTAckRule:
    Type: 'AWS::IoT::TopicRule'
    Properties:
      TopicRulePayload:
        Actions:
          - Lambda:
              FunctionArn: !Sub 'arn:aws:lambda:${AWS::Region}:${AWS::AccountId}:function:${LambdaFunction}'
        Description: 'Certificate acknowledgements (CDF Certificate Vendor service)'
        AwsIotSqlVersion: '2016-03-23'
        RuleDisabled: false
        Sql: !Sub "SELECT topic(3) as deviceId, topic(4) as action, principal() as certId, * FROM '${MQTTAckTopic}'"

  LambdaFunctionGetInvocationPermission:
    Type: AWS::Lambda::Permission
    Properties:
      SourceArn: !Sub 'arn:aws:iot:${AWS::Region}:${AWS::AccountId}:rule/${MQTTGetRule}'
      Action: lambda:InvokeFunction
      Principal: iot.amazonaws.com
      FunctionName: !GetAtt LambdaFunction.Arn
      SourceAccount: !Ref AWS::AccountId

  LambdaFunctionAckInvocationPermission:
    Type: AWS::Lambda::Permission
    Properties:
      SourceArn: !Sub 'arn:aws:iot:${AWS::Region}:${AWS::AccountId}:rule/${MQTTAckRule}'
      Action: lambda:InvokeFunction
      Principal: iot.amazonaws.com
      FunctionName: !GetAtt LambdaFunction.Arn
      SourceAccount: !Ref AWS::AccountId

  LambdaExecutionRole:
    Type: AWS::IAM::Role
    Properties:
      AssumeRolePolicyDocument:
        Version: '2012-10-17'
        Statement:
          Effect: Allow
          Principal:
            Service:
              - lambda.amazonaws.com
              - iot.amazonaws.com
          Action: sts:AssumeRole
      Path: '/'
      ManagedPolicyArns:
        - !Ref ApplicationPolicies
        - arn:aws:iam::aws:policy/AWSLambdaExecute
        - arn:aws:iam::aws:policy/service-role/AWSLambdaRole
        - arn:aws:iam::aws:policy/AWSXrayWriteOnlyAccess
    Condition: KmsKeyNotProvided

  LambdaExecutionRoleWithCsr:
    Type: AWS::IAM::Role
    Properties:
      AssumeRolePolicyDocument:
        Version: '2012-10-17'
        Statement:
          Effect: Allow
          Principal:
            Service:
              - lambda.amazonaws.com
              - iot.amazonaws.com
          Action: sts:AssumeRole
      Path: '/'
      ManagedPolicyArns:
        - !Ref ApplicationPolicies
        - !Ref ApplicationCsrPolicies
        - arn:aws:iam::aws:policy/AWSLambdaExecute
        - arn:aws:iam::aws:policy/AWSXrayWriteOnlyAccess
    Condition: KmsKeyProvided

  ApplicationPolicies:
    Type: 'AWS::IAM::ManagedPolicy'
    Metadata:
      cfn_nag:
        rules_to_suppress:
          - id: W13
            reason: 'Lambda provided permissions to manage iot Core and s3 bucket'
    Properties:
      Description: 'cdf-certificatvendor application policies'
      Path: '/'
      PolicyDocument:
        Version: '2012-10-17'
        Statement:
          - Sid: 'iot'
            Action:
              - 'iot:UpdateCertificate'
            Effect: Allow
            Resource:
              - !Sub 'arn:aws:iot:${AWS::Region}:${AWS::AccountId}:cert/*'
          - Sid: 'iotgroup'
            Action:
              - 'iot:RemoveThingFromThingGroup'
            Effect: Allow
            Resource:
              - !Sub 'arn:aws:iot:${AWS::Region}:${AWS::AccountId}:thinggroup/*'
              - !Sub 'arn:aws:iot:${AWS::Region}:${AWS::AccountId}:thing/*'
          - Sid: 'iotthing'
            Action:
              - 'iot:DescribeThing'
              - 'iot:UpdateThing'
            Effect: Allow
            Resource:
              - !Sub 'arn:aws:iot:${AWS::Region}:${AWS::AccountId}:thing/*'
          - Sid: 's3bucket'
            Action:
              - 's3:ListBucket'
            Effect: Allow
            Resource:
              - !Sub 'arn:aws:s3:::${BucketName}'
          - Sid: 's3objects'
            Action:
              - 's3:Get*'
            Effect: Allow
            Resource:
              - !Sub 'arn:aws:s3:::${BucketName}/*'
          - Sid: 'mqtt'
            Action:
              - 'iot:Publish'
            Effect: Allow
            Resource:
              - !Sub 'arn:aws:iot:${AWS::Region}:${AWS::AccountId}:topic/cdf/certificates/*'
          - Sid: 'lambda'
            Action:
              - 'lambda:InvokeFunction'
              - 'lambda:Invoke'
            Effect: Allow
            Resource:
              - !Sub 'arn:aws:lambda:${AWS::Region}:${AWS::AccountId}:function:${AssetLibraryFunctionName}'

  ApplicationCsrPolicies:
    Type: 'AWS::IAM::ManagedPolicy'
    Condition: KmsKeyProvided
    Metadata:
      cfn_nag:
        rules_to_suppress:
          - id: W13
            reason: 'Policy needs to apply to IoT artifacts that are created by the CDF'
    Properties:
      Description: 'cdf-certificatvendor policies needed to generate certificates with a CSR'
      Path: '/'
      PolicyDocument:
        Version: '2012-10-17'
        Statement:
          - Sid: 'ssm'
            Action:
              - 'ssm:GetParameter*'
            Effect: Allow
            Resource: !Sub 'arn:aws:ssm:${AWS::Region}:${AWS::AccountId}:parameter/cdf-ca-key-*'
          - Sid: 'kms'
            Action:
              - 'kms:Decrypt'
            Effect: Allow
            Resource: !Sub 'arn:aws:kms:${AWS::Region}:${AWS::AccountId}:key/${KmsKeyId}'
          - Sid: 'iotca'
            Action:
              - 'iot:DescribeCaCertificate'
            Effect: Allow
            Resource: !Sub 'arn:aws:iot:${AWS::Region}:${AWS::AccountId}:cacert/*'
          - Sid: 'iot'
            Action:
              - 'iot:RegisterCertificate'
              - 'iot:AttachThingPrincipal'
              - 'iot:ListThingPrincipals'
              - 'iot:DetachThingPrincipal'
              - 'iot:ListPrincipalThings'
              - 'iot:ListAttachedPolicies'
            Effect: Allow
            Resource: '*'
          - Sid: 'iotcert'
            Action:
              - 'iot:AttachPolicy'
              - 'iot:DetachPolicy'
              - 'iot:UpdateCertificate'
              - 'iot:DeleteCertificate'
              - 'iot:GetEffectivePolicies'
            Effect: Allow
            Resource: !Sub 'arn:aws:iot:${AWS::Region}:${AWS::AccountId}:cert/*'

  LambdaFunction:
    Type: AWS::Serverless::Function
    Properties:
      FunctionName: !Sub 'cdf-certificateVendor-${Environment}'
      CodeUri: ../bundle.zip
      Handler: lambda_proxy.handler
      Layers:
        - !Ref OpenSslLambdaLayerArn
      MemorySize: 128
      Role:
        !If [
          KmsKeyProvided,
          !GetAtt LambdaExecutionRoleWithCsr.Arn,
          !GetAtt LambdaExecutionRole.Arn,
        ]
      Runtime: nodejs16.x
      Timeout: 30
      Environment:
        Variables:
          APP_CONFIG_DIR: 'config'
          APP_CONFIG: !Ref ApplicationConfigurationOverride
          ASSETLIBRARY_API_FUNCTION_NAME: !Ref AssetLibraryFunctionName
          AWS_IOT_ENDPOINT: !GetAtt IotEndpoint.address
          AWS_S3_CERTIFICATES_BUCKET: !Ref BucketName
          CERTIFICATES_CACERTIFICATEID: !Ref CaCertificateId
          POLICIES_ROTATEDCERTIFICATEPOLICY: !Ref RotatedCertificatePolicy
          AWS_ACCOUNTID: !Ref AWS::AccountId
      Tracing: Active

  IotEndpoint:
    Type: Custom::IotEndpoint
    Version: 1.0
    Properties:
      ServiceToken: !Ref CustomResourceLambdaArn

  IotThingGroup:
    Type: Custom::IotThingGroup
    Version: 1.0
    Properties:
      ServiceToken: !Ref CustomResourceLambdaArn
      ThingGroupName: !Ref ThingGroupName
    Condition: ThingGroupNameProvided

  RotateCertificatesJob:
    Type: Custom::RotateCertificatesJob
    Version: 1.0
    Properties:
      ServiceToken: !Ref CustomResourceLambdaArn
      CommandsFunctionName: !Ref CommandsFunctionName
      ThingGroupArn: !GetAtt IotThingGroup.thingGroupArn
      MQTTGetTopic: !Ref MQTTGetTopic
      MQTTAckTopic: !Ref MQTTAckTopic
    Condition: ThingGroupNameProvided