Terraform AWS KMS

This terraform module creates a KMS Customer Master Key (CMK) and its alias.

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## Prerequisites

This module has a few dependencies:

• Terraform 0.13
• Go
• github.com/stretchr/testify/assert
• github.com/gruntwork-io/terratest/modules/terraform

Examples

IMPORTANT: Since the master branch used in source varies based on new modifications, we suggest that you use the release versions here.

Simple Example

Here is an example of how you can use this module in your inventory structure:

  module "kms_key" {
    source      = "devops4mecode/kms/aws"
    version     = "1.1.0"
    name        = "kms"
    application = "devops4me"
    environment = "test"
    label_order = ["environment", "application", "name"]
    enabled     = true
    description             = "KMS key for cloudtrail"
    deletion_window_in_days = 7
    enable_key_rotation     = true
    alias                   = "alias/cloudtrail"
    policy                  = data.aws_iam_policy_document.default.json
  }

  data "aws_iam_policy_document" "default" {
    version = "2012-10-17"
    statement {
      sid    = "Enable IAM User Permissions"
      effect = "Allow"
      principals {
        type        = "AWS"
        identifiers = ["*"]
      }
      actions   = ["kms:*"]
      resources = ["*"]
    }
    statement {
      sid    = "Allow CloudTrail to encrypt logs"
      effect = "Allow"
      principals {
        type        = "Service"
        identifiers = ["cloudtrail.amazonaws.com"]
      }
      actions   = ["kms:GenerateDataKey*"]
      resources = ["*"]
      condition {
        test     = "StringLike"
        variable = "kms:EncryptionContext:aws:cloudtrail:arn"
        values   = ["arn:aws:cloudtrail:*:XXXXXXXXXXXX:trail/*"]
      }
    }

    statement {
      sid    = "Allow CloudTrail to describe key"
      effect = "Allow"
      principals {
        type        = "Service"
        identifiers = ["cloudtrail.amazonaws.com"]
      }
      actions   = ["kms:DescribeKey"]
      resources = ["*"]
    }

    statement {
      sid    = "Allow principals in the account to decrypt log files"
      effect = "Allow"
      principals {
        type        = "AWS"
        identifiers = ["*"]
      }
      actions = [
        "kms:Decrypt",
        "kms:ReEncryptFrom"
      ]
      resources = ["*"]
      condition {
        test     = "StringEquals"
        variable = "kms:CallerAccount"
        values = [
        "XXXXXXXXXXXX"]
      }
      condition {
        test     = "StringLike"
        variable = "kms:EncryptionContext:aws:cloudtrail:arn"
        values   = ["arn:aws:cloudtrail:*:XXXXXXXXXXXX:trail/*"]
      }
    }

    statement {
      sid    = "Allow alias creation during setup"
      effect = "Allow"
      principals {
        type        = "AWS"
        identifiers = ["*"]
      }
      actions   = ["kms:CreateAlias"]
      resources = ["*"]
    }
  }

Inputs

Name	Description	Type	Default	Required
alias	The display name of the alias. The name must start with the word alias followed by a forward slash.	string	""	no
application	Application (e.g. do4m or devops4me).	string	""	no
attributes	Additional attributes (e.g. 1).	list(string)	[]	no
customer_master_key_spec	Specifies whether the key contains a symmetric key or an asymmetric key pair and the encryption algorithms or signing algorithms that the key supports. Valid values: SYMMETRIC_DEFAULT, RSA_2048, RSA_3072, RSA_4096, ECC_NIST_P256, ECC_NIST_P384, ECC_NIST_P521, or ECC_SECG_P256K1. Defaults to SYMMETRIC_DEFAULT.	string	"SYMMETRIC_DEFAULT"	no
deletion_window_in_days	Duration in days after which the key is deleted after destruction of the resource.	number	10	no
description	The description of the key as viewed in AWS console.	string	"Parameter Store KMS master key"	no
enable_key_rotation	Specifies whether key rotation is enabled.	bool	true	no
enabled	Specifies whether the kms is enabled or disabled.	bool	true	no
environment	Environment (e.g. prod, dev, staging).	string	""	no
is_enabled	Specifies whether the key is enabled.	bool	true	no
key_usage	Specifies the intended use of the key. Defaults to ENCRYPT_DECRYPT, and only symmetric encryption and decryption are supported.	string	"ENCRYPT_DECRYPT"	no
label_order	label order, e.g. name,application.	list	[]	no
managedby	ManagedBy, eg 'DevOps4Me' or 'NajibRadzuan'.	string	"[email protected]"	no
name	Name (e.g. app or cluster).	string	""	no
policy	A valid policy JSON document. For more information about building AWS IAM policy documents with Terraform.	string	""	no
tags	Additional tags (e.g. map(BusinessUnit,XYZ).	map(string)	{}	no

Outputs

Name	Description
alias_arn	Alias ARN.
alias_name	Alias name.
key_arn	Key ARN.
key_id	Key ID.
tags	A mapping of tags to assign to the resource.

Testing

In this module testing is performed with terratest and it creates a small piece of infrastructure, matches the output like ARN, ID and Tags name etc and destroy infrastructure in your AWS account. This testing is written in GO, so you need a GO environment in your system.

You need to run the following command in the testing folder:

  go test -run Test