update response header policy (#8)

<!-- markdownlint-disable-next-line first-line-heading -->
## Description
Remove server and opennext header from cloudfront response
<!-- Describe your changes in detail. -->

## Context

<!-- Why is this change required? What problem does it solve? -->
NDOP Pen test
## Type of changes

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the boxes that apply. -->

- [x] Refactoring (non-breaking change)
- [x] New feature (non-breaking change which adds functionality)
- [ ] Breaking change (fix or feature that would change existing
functionality)
- [ ] Bug fix (non-breaking change which fixes an issue)

## Checklist

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that apply. -->

- [x] I am familiar with the [contributing
guidelines](../docs/CONTRIBUTING.md)
- [x] I have followed the code style of the project
- [x] I have added tests to cover my changes
- [x] I have updated the documentation accordingly
- [x] This PR is a result of pair or mob programming

---

## Sensitive Information Declaration

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locals.tf

@@ -28,6 +28,9 @@ locals {
       override                   = true
       preload                    = true
     }, var.cloudfront.hsts)
+    remove_headers_config = merge({
+      items : []
+    }, var.cloudfront.remove_headers_config)
     waf_logging_configuration = var.cloudfront.waf_logging_configuration
     cache_policy = {
       default_ttl                   = coalesce(try(var.cloudfront.cache_policy.default_ttl, null), 0)

main.tf

@@ -217,4 +217,5 @@ module "cloudfront" {
   hsts                      = local.cloudfront.hsts
   waf_logging_configuration = local.cloudfront.waf_logging_configuration
   cache_policy              = local.cloudfront.cache_policy
+  remove_headers_config     = local.cloudfront.remove_headers_config
 }

modules/cloudfront-logs/kms.tf

@@ -4,7 +4,7 @@ resource "aws_kms_key" "cloudwatch_logs_key" {
   description             = "KMS Key for ${var.log_group_name} log group"
   deletion_window_in_days = 10
   policy                  = data.aws_iam_policy_document.cloudwatch_logs_key_policy[0].json
-  enable_key_rotation = true
+  enable_key_rotation     = true
 }
 
 data "aws_iam_policy_document" "cloudwatch_logs_key_policy" {

modules/opennext-assets/s3.tf

@@ -166,18 +166,18 @@ data "aws_iam_policy_document" "read_assets_bucket" {
     }
   }
   statement {
-    effect = "Deny"
-    actions = ["s3:*"]
+    effect    = "Deny"
+    actions   = ["s3:*"]
     resources = [aws_s3_bucket.assets.arn, "${aws_s3_bucket.assets.arn}/*"]
 
     condition {
-      test = "Bool"
-      values = ["false"]
+      test     = "Bool"
+      values   = ["false"]
       variable = "aws:SecureTransport"
     }
 
     principals {
-      type = "*"
+      type        = "*"
       identifiers = ["*"]
     }
   }

modules/opennext-cloudfront/cloudfront.tf

@@ -146,6 +146,19 @@ resource "aws_cloudfront_response_headers_policy" "response_headers_policy" {
       }
     }
   }
+  dynamic "remove_headers_config" {
+    for_each = length(var.remove_headers_config.items) > 0 ? [true] : []
+
+    content {
+      dynamic "items" {
+        for_each = toset(var.remove_headers_config.items)
+
+        content {
+          header = items.value
+        }
+      }
+    }
+  }
 }
 
 resource "aws_cloudfront_distribution" "distribution" {

modules/opennext-cloudfront/variables.tf

@@ -162,3 +162,11 @@ variable "geo_restriction" {
     locations        = list(string)
   })
 }
+
+variable "remove_headers_config" {
+  description = "Response header removal configuration for the CloudFront distribution"
+  type = object({
+    items = list(string)
+  })
+}
+

modules/opennext-revalidation-queue/kms.tf

@@ -9,7 +9,7 @@ resource "aws_kms_key" "revalidation_queue_key" {
   description             = "${var.prefix} Revalidation SQS Queue KMS Key"
   deletion_window_in_days = 10
 
-  policy = data.aws_iam_policy_document.revalidation_queue_key_policy[0].json
+  policy              = data.aws_iam_policy_document.revalidation_queue_key_policy[0].json
   enable_key_rotation = true
 }
 

variables.tf

@@ -327,6 +327,9 @@ variable "cloudfront" {
       allow_origins     = list(string)
       origin_override   = bool
     }))
+    remove_headers_config = optional(object({
+      items = list(string)
+    }))
     hsts = optional(object({
       access_control_max_age_sec = number
       include_subdomains         = bool