feat(secretsmanager): exclude characters for hosted rotation (#20768)

By default, use the exclude characters of the secret if available or
the same default exclude characters as the ones used in `@aws-cdk/aws-rds`.

A subsequent PR should replace the secret rotation implementation in
`@aws-cdk/aws-rds` with a hosted rotation now that exclude chars are
supported.


----

### All Submissions:

* [x] Have you followed the guidelines in our [Contributing guide?](https://github.com/aws/aws-cdk/blob/main/CONTRIBUTING.md)

### Adding new Unconventional Dependencies:

* [ ] This PR adds new unconventional dependencies following the process described [here](https://github.com/aws/aws-cdk/blob/main/CONTRIBUTING.md/#adding-new-unconventional-dependencies)

### New Features

* [x] Have you added the new feature to an [integration test](https://github.com/aws/aws-cdk/blob/main/INTEGRATION_TESTS.md)?
	* [x] Did you use `yarn integ` to deploy the infrastructure and generate the snapshot (i.e. `yarn integ` without `--dry-run`)?

*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-secretsmanager/README.md

@@ -145,6 +145,12 @@ secret.addRotationSchedule('RotationSchedule', { hostedRotation: myHostedRotatio
 dbConnections.allowDefaultPortFrom(myHostedRotation);
 ```
 
+Use the `excludeCharacters` option to customize the characters excluded from
+the generated password when it is rotated. By default, the rotation excludes
+the same characters as the ones excluded for the secret. If none are defined
+then the following set is used: ``% +~`#$&*()|[]{}:;<>?!'/@"\``.
+
+
 See also [Automating secret creation in AWS CloudFormation](https://docs.aws.amazon.com/secretsmanager/latest/userguide/integrating_cloudformation.html).
 
 ## Rotating database credentials

packages/@aws-cdk/aws-secretsmanager/lib/rotation-schedule.ts

@@ -4,9 +4,17 @@ import * as kms from '@aws-cdk/aws-kms';
 import * as lambda from '@aws-cdk/aws-lambda';
 import { Duration, Resource, Stack } from '@aws-cdk/core';
 import { Construct } from 'constructs';
-import { ISecret } from './secret';
+import { ISecret, Secret } from './secret';
 import { CfnRotationSchedule } from './secretsmanager.generated';
 
+/**
+ * The default set of characters we exclude from generated passwords for database users.
+ * It's a combination of characters that have a tendency to cause problems in shell scripts,
+ * some engine-specific characters (for example, Oracle doesn't like '@' in its passwords),
+ * and some that trip up other services, like DMS.
+ */
+const DEFAULT_PASSWORD_EXCLUDE_CHARS = " %+~`#$&*()|[]{}:;<>?!'/@\"\\";
+
 /**
  * Options to add a rotation schedule to a secret.
  */
@@ -162,6 +170,14 @@ export interface SingleUserHostedRotationOptions {
    * @default - the Vpc default strategy if not specified.
    */
   readonly vpcSubnets?: ec2.SubnetSelection;
+
+  /**
+   * A string of the characters that you don't want in the password
+   *
+   * @default the same exclude characters as the ones used for the
+   * secret or " %+~`#$&*()|[]{}:;<>?!'/@\"\\"
+   */
+  readonly excludeCharacters?: string,
 }
 
 /**
@@ -284,6 +300,10 @@ export class HostedRotation implements ec2.IConnectable {
       this.masterSecret.denyAccountRootDelete();
     }
 
+    const defaultExcludeCharacters = Secret.isSecret(secret)
+      ? secret.excludeCharacters ?? DEFAULT_PASSWORD_EXCLUDE_CHARS
+      : DEFAULT_PASSWORD_EXCLUDE_CHARS;
+
     return {
       rotationType: this.type.name,
       kmsKeyArn: secret.encryptionKey?.keyArn,
@@ -292,6 +312,7 @@ export class HostedRotation implements ec2.IConnectable {
       rotationLambdaName: this.props.functionName,
       vpcSecurityGroupIds: this._connections?.securityGroups?.map(s => s.securityGroupId).join(','),
       vpcSubnetIds: this.props.vpc?.selectSubnets(this.props.vpcSubnets).subnetIds.join(','),
+      excludeCharacters: this.props.excludeCharacters ?? defaultExcludeCharacters,
     };
   }
 

packages/@aws-cdk/aws-secretsmanager/lib/secret.ts

@@ -7,6 +7,8 @@ import { ResourcePolicy } from './policy';
 import { RotationSchedule, RotationScheduleOptions } from './rotation-schedule';
 import * as secretsmanager from './secretsmanager.generated';
 
+const SECRET_SYMBOL = Symbol.for('@aws-cdk/secretsmanager.Secret');
+
 /**
  * A secret in AWS Secrets Manager.
  */
@@ -446,6 +448,12 @@ abstract class SecretBase extends Resource implements ISecret {
  * Creates a new secret in AWS SecretsManager.
  */
 export class Secret extends SecretBase {
+  /**
+   * Return whether the given object is a Secret.
+   */
+  public static isSecret(x: any): x is Secret {
+    return x !== null && typeof(x) === 'object' && SECRET_SYMBOL in x;
+  }
 
   /** @deprecated use `fromSecretCompleteArn` or `fromSecretPartialArn` */
   public static fromSecretArn(scope: Construct, id: string, secretArn: string): ISecret {
@@ -553,6 +561,12 @@ export class Secret extends SecretBase {
   public readonly secretArn: string;
   public readonly secretName: string;
 
+  /**
+   * The string of the characters that are excluded in this secret
+   * when it is generated.
+   */
+  public readonly excludeCharacters?: string;
+
   private replicaRegions: secretsmanager.CfnSecret.ReplicaRegionProperty[] = [];
 
   protected readonly autoCreatePolicy = true;
@@ -609,6 +623,8 @@ export class Secret extends SecretBase {
     for (const replica of props.replicaRegions ?? []) {
       this.addReplicaRegion(replica.region, replica.encryptionKey);
     }
+
+    this.excludeCharacters = props.generateSecretString?.excludeCharacters;
   }
 
   /**
@@ -925,3 +941,12 @@ function parseSecretNameForOwnedSecret(construct: Construct, secretArn: string,
 function arnIsComplete(secretArn: string): boolean {
   return Token.isUnresolved(secretArn) || /-[a-z0-9]{6}$/i.test(secretArn);
 }
+
+/**
+ * Mark all instances of 'Secret'.
+ */
+Object.defineProperty(Secret.prototype, SECRET_SYMBOL, {
+  value: true,
+  enumerable: false,
+  writable: false,
+});

packages/@aws-cdk/aws-secretsmanager/test/hosted-rotation.integ.snapshot/cdk-integ-secret-hosted-rotation.assets.json

@@ -0,0 +1,19 @@
+{
+  "version": "20.0.0",
+  "files": {
+    "80e7147ae17e29a7810c1890b8caa90a140f0089dcb2dce470bd13d88e5acc41": {
+      "source": {
+        "path": "cdk-integ-secret-hosted-rotation.template.json",
+        "packaging": "file"
+      },
+      "destinations": {
+        "current_account-current_region": {
+          "bucketName": "cdk-hnb659fds-assets-${AWS::AccountId}-${AWS::Region}",
+          "objectKey": "80e7147ae17e29a7810c1890b8caa90a140f0089dcb2dce470bd13d88e5acc41.json",
+          "assumeRoleArn": "arn:${AWS::Partition}:iam::${AWS::AccountId}:role/cdk-hnb659fds-file-publishing-role-${AWS::AccountId}-${AWS::Region}"
+        }
+      }
+    }
+  },
+  "dockerImages": {}
+}

packages/@aws-cdk/aws-secretsmanager/test/hosted-rotation.integ.snapshot/cdk-integ-secret-hosted-rotation.template.json

@@ -1,5 +1,7 @@
 {
- "Transform": "AWS::SecretsManager-2020-07-23",
+ "Transform": [
+  "AWS::SecretsManager-2020-07-23"
+ ],
  "Resources": {
   "SecretA720EF05": {
    "Type": "AWS::SecretsManager::Secret",
@@ -16,6 +18,7 @@
      "Ref": "SecretA720EF05"
     },
     "HostedRotationLambda": {
+     "ExcludeCharacters": " %+~`#$&*()|[]{}:;<>?!'/@\"\\",
      "RotationType": "MySQLSingleUser"
     },
     "RotationRules": {
@@ -58,6 +61,67 @@
      "Ref": "SecretA720EF05"
     }
    }
+  },
+  "CustomSecret5DC95D87": {
+   "Type": "AWS::SecretsManager::Secret",
+   "Properties": {
+    "GenerateSecretString": {
+     "ExcludeCharacters": "&@/"
+    }
+   },
+   "UpdateReplacePolicy": "Delete",
+   "DeletionPolicy": "Delete"
+  },
+  "CustomSecretScheduleDD99F351": {
+   "Type": "AWS::SecretsManager::RotationSchedule",
+   "Properties": {
+    "SecretId": {
+     "Ref": "CustomSecret5DC95D87"
+    },
+    "HostedRotationLambda": {
+     "ExcludeCharacters": "&@/",
+     "RotationType": "MySQLSingleUser"
+    },
+    "RotationRules": {
+     "AutomaticallyAfterDays": 30
+    }
+   }
+  },
+  "CustomSecretPolicy8E81D2EB": {
+   "Type": "AWS::SecretsManager::ResourcePolicy",
+   "Properties": {
+    "ResourcePolicy": {
+     "Statement": [
+      {
+       "Action": "secretsmanager:DeleteSecret",
+       "Effect": "Deny",
+       "Principal": {
+        "AWS": {
+         "Fn::Join": [
+          "",
+          [
+           "arn:",
+           {
+            "Ref": "AWS::Partition"
+           },
+           ":iam::",
+           {
+            "Ref": "AWS::AccountId"
+           },
+           ":root"
+          ]
+         ]
+        }
+       },
+       "Resource": "*"
+      }
+     ],
+     "Version": "2012-10-17"
+    },
+    "SecretId": {
+     "Ref": "CustomSecret5DC95D87"
+    }
+   }
   }
  }
 }

packages/@aws-cdk/aws-secretsmanager/test/hosted-rotation.integ.snapshot/cdk.out

@@ -1 +1 @@
-{"version":"17.0.0"}
+{"version":"20.0.0"}

packages/@aws-cdk/aws-secretsmanager/test/hosted-rotation.integ.snapshot/integ.json

@@ -1,7 +1,7 @@
 {
-  "version": "18.0.0",
+  "version": "20.0.0",
   "testCases": {
-    "aws-secretsmanager/test/integ.hosted-rotation": {
+    "integ.hosted-rotation": {
       "stacks": [
         "cdk-integ-secret-hosted-rotation"
       ],

packages/@aws-cdk/aws-secretsmanager/test/hosted-rotation.integ.snapshot/manifest.json

@@ -1,5 +1,5 @@
 {
-  "version": "17.0.0",
+  "version": "20.0.0",
   "artifacts": {
     "Tree": {
       "type": "cdk:tree",
@@ -32,6 +32,24 @@
             "type": "aws:cdk:logicalId",
             "data": "SecretPolicy06C9821C"
           }
+        ],
+        "/cdk-integ-secret-hosted-rotation/CustomSecret/Resource": [
+          {
+            "type": "aws:cdk:logicalId",
+            "data": "CustomSecret5DC95D87"
+          }
+        ],
+        "/cdk-integ-secret-hosted-rotation/CustomSecret/Schedule/Resource": [
+          {
+            "type": "aws:cdk:logicalId",
+            "data": "CustomSecretScheduleDD99F351"
+          }
+        ],
+        "/cdk-integ-secret-hosted-rotation/CustomSecret/Policy/Resource": [
+          {
+            "type": "aws:cdk:logicalId",
+            "data": "CustomSecretPolicy8E81D2EB"
+          }
         ]
       },
       "displayName": "cdk-integ-secret-hosted-rotation"