Terraform Parliament - Run Parliament AWS IAM Checker on Terraform Files

Parliament checks IAM policy validity against the latest AWS IAM specifications, so e.g. It'll pick up if your policy uses an older Action like billing:*, instead of the current aws-portal:*

By default, Parliament runs only on JSON IAM policies, not Terraform files. However I wanted to validate my Terraform files.

This utility parses your Terraform, finds aws_iam_policy_document elements, generates resulting IAM policy document strings, and runs Parliament on them.

It stubs any Terraform interpolations ${...} so they can be evaluated by Parliament as valid JSON.

Terraform Resource Support

Resource Type	Supported?
aws_iam_policy	Yes only inline policy not file()
aws_iam_policy_document	Yes
aws_iam_user_policy	No
aws_iam_group_policy	No
aws_iam_role_policy	No
aws_s3_bucket_policy	No
aws_[ecr|efs|iot|media_store_container|organizations]*_policy	No
data.template_file	No

The unsupported resource types should be pretty easy to add, if anyone feels a PR coming on :)

Issues

• Sometimes the interpolation stubbing (e.g. "Replace all ${...} in a Resource with *") results in invalid values; needs to be more sophisticated than current regex replace
• No unit tests :(
• Currently not fit to be used as a GitHub action (as was my plan) since --recursive not yet implemented
• You will receive RESOURCE_MISMATCH if you have a policy with action Get* and resource ending in /* (referring to objects in a bucket), since s3:Get* includes some permissions which are bucket-level, not object-level. I have tried allowing you to ignore this by implementing config override per Parliament doco, and calling parliament.override_config(), to no avail
• aws_iam_policy is supported, but only inline policy; not file()
• data.template_file not supported

Usage

Docker

DockerHub Repo

Use /github/workspace/ to mount the directory containing the Terraform, since this image is intended to run as a GitHub action:

Intention	Command
Run on the entire directory	docker run --rm -ti -v (pwd):/github/workspace/ rdkls/tf-parliament
Run on one file	docker run --rm -ti -v (pwd):/github/workspace/ rdkls/tf-parliament iam.tf
Run on some TF files only	docker run --rm -ti -v (pwd):/github/workspace/ rdkls/tf-parliament 'iam-*.tf'

Notes

• These examples use fish shell (pwd), in bash switch that to `pwd`
• Quotes around the argument in the last example, to avoid your shell expanding the wildcard before passing to docker.

Native

pip install -r requirements.txt

tf-parliament.py my-template.tf

(also supports wildcards & directories per Docker method)

Requirements

• Docker
• Terraform Files v0.12+ (though v0.11 should work too)