feat(apigateway): mTLS support (#10521)

Resolves #10487 

----

*By submitting this pull request, I confirm that my contribution is made under the terms of the Apache-2.0 license*

packages/@aws-cdk/aws-apigateway/README.md

@@ -30,6 +30,7 @@ running on AWS Lambda, or any web application.
   - [IAM-based authorizer](#iam-based-authorizer)
   - [Lambda-based token authorizer](#lambda-based-token-authorizer)
   - [Lambda-based request authorizer](#lambda-based-request-authorizer)
+- [Mutual TLS](#mutal-tls-mtls)
 - [Deployments](#deployments)
   - [Deep dive: Invalidation of deployments](#deep-dive-invalidation-of-deployments)
 - [Custom Domains](#custom-domains)
@@ -573,6 +574,24 @@ Authorizers can also be passed via the `defaultMethodOptions` property within th
 explicitly overridden, the specified defaults will be applied across all `Method`s across the `RestApi` or across all `Resource`s,
 depending on where the defaults were specified.
 
+## Mutual TLS (mTLS)
+
+Mutual TLS can be configured to limit access to your API based by using client certificates instead of (or as an extension of) using authorization headers.
+
+```ts
+new apigw.DomainName(this, 'domain-name', {
+  domainName: 'example.com',
+  certificate: acm.Certificate.fromCertificateArn(this, 'cert' 'arn:aws:acm:us-east-1:1111111:certificate/11-3336f1-44483d-adc7-9cd375c5169d'),
+  mtls: {
+    bucket: new Bucket(this, 'bucket')),
+    key: 'truststore.pem',
+    version: 'version',
+  },
+});
+```
+
+Instructions for configuring your trust store can be found [here](https://aws.amazon.com/blogs/compute/introducing-mutual-tls-authentication-for-amazon-api-gateway/).
+
 ## Deployments
 
 By default, the `RestApi` construct will automatically create an API Gateway

packages/@aws-cdk/aws-apigateway/lib/domain-name.ts

@@ -1,4 +1,5 @@
 import * as acm from '@aws-cdk/aws-certificatemanager';
+import { IBucket } from '@aws-cdk/aws-s3';
 import { IResource, Resource, Token } from '@aws-cdk/core';
 import { Construct } from 'constructs';
 import { CfnDomainName } from './apigateway.generated';
@@ -40,6 +41,12 @@ export interface DomainNameOptions {
    * @default SecurityPolicy.TLS_1_0
    */
   readonly securityPolicy?: SecurityPolicy
+
+  /**
+   * The mutual TLS authentication configuration for a custom domain name.
+   * @default - mTLS is not configured.
+   */
+  readonly mtls?: MTLSConfig
 }
 
 export interface DomainNameProps extends DomainNameOptions {
@@ -76,6 +83,7 @@ export interface IDomainName extends IResource {
    * @attribute DistributionHostedZoneId,RegionalHostedZoneId
    */
   readonly domainNameAliasHostedZoneId: string;
+
 }
 
 export class DomainName extends Resource implements IDomainName {
@@ -107,12 +115,13 @@ export class DomainName extends Resource implements IDomainName {
       throw new Error('domainName does not support uppercase letters. ' +
         `got: '${props.domainName}'`);
     }
-
+    const mtlsConfig = this.configureMTLS(props.mtls);
     const resource = new CfnDomainName(this, 'Resource', {
       domainName: props.domainName,
       certificateArn: edge ? props.certificate.certificateArn : undefined,
       regionalCertificateArn: edge ? undefined : props.certificate.certificateArn,
       endpointConfiguration: { types: [endpointType] },
+      mutualTlsAuthentication: mtlsConfig,
       securityPolicy: props.securityPolicy,
     });
 
@@ -145,6 +154,14 @@ export class DomainName extends Resource implements IDomainName {
       ...options,
     });
   }
+
+  private configureMTLS(mtlsConfig?: MTLSConfig): CfnDomainName.MutualTlsAuthenticationProperty | undefined {
+    if (!mtlsConfig) return undefined;
+    return {
+      truststoreUri: mtlsConfig.bucket.s3UrlForObject(mtlsConfig.key),
+      truststoreVersion: mtlsConfig.version,
+    };
+  }
 }
 
 export interface DomainNameAttributes {
@@ -162,4 +179,26 @@ export interface DomainNameAttributes {
    * Thje Route53 hosted zone ID to use in order to connect a record set to this domain through an alias.
    */
   readonly domainNameAliasHostedZoneId: string;
+
+}
+
+/**
+ * The mTLS authentication configuration for a custom domain name.
+ */
+export interface MTLSConfig {
+  /**
+   * The bucket that the trust store is hosted in.
+   */
+  readonly bucket: IBucket;
+  /**
+   * The key in S3 to look at for the trust store
+   */
+  readonly key: string;
+
+  /**
+   *  The version of the S3 object that contains your truststore.
+   *  To specify a version, you must have versioning enabled for the S3 bucket.
+   *  @default - latest version
+   */
+  readonly version?: string;
 }

packages/@aws-cdk/aws-apigateway/test/test.domains.ts

@@ -1,5 +1,6 @@
 import { ABSENT, expect, haveResource } from '@aws-cdk/assert';
 import * as acm from '@aws-cdk/aws-certificatemanager';
+import { Bucket } from '@aws-cdk/aws-s3';
 import { Stack } from '@aws-cdk/core';
 import { Test } from 'nodeunit';
 import * as apigw from '../lib';
@@ -399,4 +400,47 @@ export = {
     }));
     test.done();
   },
+
+  'accepts a mutual TLS configuration'(test: Test) {
+    const stack = new Stack();
+    const bucket = Bucket.fromBucketName(stack, 'testBucket', 'exampleBucket');
+    new apigw.DomainName(stack, 'another-domain', {
+      domainName: 'example.com',
+      mtls: {
+        bucket,
+        key: 'someca.pem',
+      },
+      certificate: acm.Certificate.fromCertificateArn(stack, 'cert', 'arn:aws:acm:us-east-1:1111111:certificate/11-3336f1-44483d-adc7-9cd375c5169d'),
+    });
+
+    expect(stack).to(haveResource('AWS::ApiGateway::DomainName', {
+      'DomainName': 'example.com',
+      'EndpointConfiguration': { 'Types': ['REGIONAL'] },
+      'RegionalCertificateArn': 'arn:aws:acm:us-east-1:1111111:certificate/11-3336f1-44483d-adc7-9cd375c5169d',
+      'MutualTlsAuthentication': { 'TruststoreUri': 's3://exampleBucket/someca.pem' },
+    }));
+    test.done();
+  },
+
+  'mTLS should allow versions to be set on the s3 bucket'(test: Test) {
+    const stack = new Stack();
+    const bucket = Bucket.fromBucketName(stack, 'testBucket', 'exampleBucket');
+    new apigw.DomainName(stack, 'another-domain', {
+      domainName: 'example.com',
+      certificate: acm.Certificate.fromCertificateArn(stack, 'cert2', 'arn:aws:acm:us-east-1:1111111:certificate/11-3336f1-44483d-adc7-9cd375c5169d'),
+      mtls: {
+        bucket,
+        key: 'someca.pem',
+        version: 'version',
+      },
+    });
+    expect(stack).to(haveResource('AWS::ApiGateway::DomainName', {
+      'DomainName': 'example.com',
+      'EndpointConfiguration': { 'Types': ['REGIONAL'] },
+      'RegionalCertificateArn': 'arn:aws:acm:us-east-1:1111111:certificate/11-3336f1-44483d-adc7-9cd375c5169d',
+      'MutualTlsAuthentication': { 'TruststoreUri': 's3://exampleBucket/someca.pem', 'TruststoreVersion': 'version' },
+    }));
+    test.done();
+  },
+
 };