OpenID Connect for AWS and GitHub Actions

Terraform module to configure GitHub Actions as an IAM OIDC identity provider in AWS. OpenID Connect allows GitHub Actions workflows to access resources in AWS without requiring AWS credentials to be stored as long-lived GitHub secrets.

🔨 Getting started

Requirements

• AWS Provider 4.0+
• TLS Provider 3.0+
• Terraform 1.0+

Installation and usage

Refer to the complete example to view all the available configuration options. The following snippet shows the minimum required configuration to create a working OIDC connection between GitHub Actions and AWS.

module "oidc_github" {
  source  = "unfunco/oidc-github/aws"
  version = "1.8.0"

  github_repositories = [
    "org/repo",
    "another-org/another-repo:ref:refs/heads/main",
  ]
}

The following demonstrates how to use GitHub Actions once the Terraform module has been applied to your AWS account. The action receives a JSON Web Token (JWT) from the GitHub OIDC provider and then requests an access token from AWS.

jobs:
  caller-identity:
    name: Check caller identity
    permissions:
      contents: read
      id-token: write
    runs-on: ubuntu-latest
    steps:
    - name: Configure AWS credentials
      uses: aws-actions/configure-aws-credentials@v4
      with:
        aws-region: ${{ env.AWS_REGION }}
        role-to-assume: arn:aws:iam::${{ env.AWS_ACCOUNT_ID }}:role/github
    - run: aws sts get-caller-identity

Enterprise Cloud

Organisations using GitHub Enterprise Cloud can further improve their security posture by setting the enterprise_slug variable. This configuration ensures that the organisation will receive OIDC tokens from a unique URL, after this is applied, the JWT will contain an updated iss claim.

Resources

Name	Type
aws_iam_openid_connect_provider.github	resource
aws_iam_role.github	resource
aws_iam_role_policy_attachment.admin	resource
aws_iam_role_policy_attachment.custom	resource
aws_iam_role_policy_attachment.read_only	resource
aws_iam_openid_connect_provider.github	data source
aws_iam_policy_document.assume_role	data source
aws_partition.current	data source
tls_certificate.github	data source

Inputs

Name	Description	Type	Default	Required
additional_audiences	List of additional OIDC audiences allowed to assume the role.	list(string)	null	no
additional_thumbprints	List of additional thumbprints for the OIDC provider.	list(string)	[]	no
attach_admin_policy	Flag to enable/disable the attachment of the AdministratorAccess policy.	bool	false	no
attach_read_only_policy	Flag to enable/disable the attachment of the ReadOnly policy.	bool	true	no
create_oidc_provider	Flag to enable/disable the creation of the GitHub OIDC provider.	bool	true	no
enabled	Flag to enable/disable the creation of resources.	bool	true	no
enterprise_slug	Enterprise slug for GitHub Enterprise Cloud customers.	string	""	no
force_detach_policies	Flag to force detachment of policies attached to the IAM role.	bool	false	no
github_repositories	List of GitHub organization/repository names authorized to assume the role.	list(string)	n/a	yes
iam_role_inline_policies	Inline policies map with policy name as key and json as value.	map(string)	{}	no
iam_role_name	Name of the IAM role to be created. This will be assumable by GitHub.	string	"github"	no
iam_role_path	Path under which to create IAM role.	string	"/"	no
iam_role_permissions_boundary	ARN of the permissions boundary to be used by the IAM role.	string	""	no
iam_role_policy_arns	List of IAM policy ARNs to attach to the IAM role.	list(string)	[]	no
max_session_duration	Maximum session duration in seconds.	number	3600	no
tags	Map of tags to be applied to all resources.	map(string)	{}	no

Outputs

Name	Description
iam_role_arn	ARN of the IAM role.
iam_role_name	Name of the IAM role.
oidc_provider_arn	ARN of the OIDC provider.

References

• Configuring OpenID Connect in Amazon Web Services
• Creating OpenID Connect (OIDC) identity providers
• Obtaining the thumbprint for an OpenID Connect Identity Provider
• GitHub Actions – Update on OIDC integration with AWS

License

© 2021 Daniel Morris
Made available under the terms of the Apache License 2.0.