fix(cdk): allow EB runtime version ACL read

infra/cdk/README.md

@@ -48,7 +48,8 @@ The role grants only:
   `s3:PutObject`, `s3:GetObject`, and `s3:GetObjectVersion`, which the pinned
   official deployment action requires to validate the
   `CreateApplicationVersion` source bundle after upload.
-- `s3:PutObject`, `s3:GetObject`, and `s3:DeleteObject` on only
+- `s3:PutObject`, `s3:GetObject`, `s3:GetObjectVersionAcl`, and
+  `s3:DeleteObject` on only
   `elasticbeanstalk-us-east-1-396287094661/resources/environments/e-hehnrqjjrt/_runtime/_versions/shoc-backend/*`.
   Elastic Beanstalk copies each uploaded source bundle into this
   environment-specific runtime prefix during `UpdateEnvironment`, verifies it
@@ -56,9 +57,10 @@ The role grants only:
   copy after the version is registered. Attempts 1 through 4 of run
   `30448885838` exposed the exact source, destination, cleanup, and verification
   operations after the earlier ACL denial was resolved. CloudTrail recorded
-  the exact `s3:GetObject` denial on attempt 4. The grant does not cover another
-  environment, another application, source bundles, object versions, bucket
-  ACLs, object ACLs, tags, or retention.
+  the exact `s3:GetObject` denial on attempt 4; attempt 6 then exposed the
+  version-specific ACL read performed on the copied object. The grant does not
+  cover another environment, another application, source bundles, object
+  content versions, ACL mutation, tags, or retention.
 - `s3:GetObjectAcl` on objects under the service-wide
   `arn:aws:s3:::elasticbeanstalk-*/*` namespace. AWS Support case
   `178526484500047` confirmed that `UpdateEnvironment` uses the initiating

infra/cdk/deploy-dev-stack.ts

@@ -153,7 +153,12 @@ export class DeployDevStack extends cdk.Stack {
     deployRole.addToPolicy(
       new iam.PolicyStatement({
         effect: iam.Effect.ALLOW,
-        actions: ['s3:DeleteObject', 's3:GetObject', 's3:PutObject'],
+        actions: [
+          's3:DeleteObject',
+          's3:GetObject',
+          's3:GetObjectVersionAcl',
+          's3:PutObject',
+        ],
         // UpdateEnvironment copies the uploaded source bundle into this
         // environment-specific runtime prefix, verifies the temporary copy,
         // and removes it after the version is registered.