This action enables workflows to obtain AWS Access Credentials for a desired IAM Role using AWS IAM SAML and a GitHub Actions Repository Token.

Benefits:

• No need to copy/paste AWS Access Tokens into GitHub Secrets
• No need to rotate AWS Access Tokens

This action uses SAML.to and an AWS IAM Identity Provider to exchange a GitHub Actions Token for AWS Access Credentials.

This action will set the following environment variables:

• AWS_ACCESS_KEY_ID
• AWS_SECRET_ACCESS_KEY
• AWS_SESSION_TOKEN
• AWS_DEFAULT_REGION

See action.yml

steps:
  - uses: saml-to/assume-aws-role-action@v1
    with:
      role: arn:aws:iam::123456789012:role/admin
    env:
      GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
  - run: aws sts get-caller-identity
  - run: aws ec2 describe-instances

See aws-assume-role-action-examples

1. Download Your Metadata from SAML.to

2. Create a new SAML Identity Provider in AWS IAM

   1. Provider Name: Repository Name (the name of the repository running the action)
   2. Metadata Document: Upload the Metadata Document from SAML.to
   3. Make note of the Provder ARN in the AWS console

3. Create or update the Trust Relationship on a new or existing IAM Role to contain the following:

   {
     "Version": "2012-10-17",
     "Statement": [
       {
         "Effect": "Allow",
         "Principal": {
           "Federated": "PROVIDER_ARN"
         },
         "Action": "sts:AssumeRoleWithSAML",
         "Condition": {
           "StringEquals": {
             "SAML:aud": "https://signin.aws.amazon.com/saml"
           }
         }
       }
     ]
   }
   

   • Replace PROVIDER_ARN with the newly created ARN of the provider, e.g. arn:aws:iam::123456789012:saml-provider/my-repository
   • Make note of the Role ARN for this Role

4. Add a new file named saml-to.yml to the repository that needs AWS Access Credentials during GitHub Actions:

   your-repository/saml-to.yml:

   ---
   version: "20220101"
   variables:
     awsProviderArn: "PROVIDER_ARN"
     awsRoleArn: "ROLE_ARN"
   providers:
     aws:
       entityId: https://signin.aws.amazon.com/saml
       acsUrl: https://signin.aws.amazon.com/saml
       attributes:
         https://aws.amazon.com/SAML/Attributes/RoleSessionName: "<#= repo.name #>"
         https://aws.amazon.com/SAML/Attributes/SessionDuration: "3600"
         https://aws.amazon.com/SAML/Attributes/Role: "<#= repo.selectedRole #>,<$= awsProviderArn $>"
   permissions:
     aws:
       roles:
         - name: <$= awsRoleArn $>
           self: true
   

   • Replace PROVIDER_ARN with the ARN of the provider created above (e.g. arn:aws:iam::123456689012:saml-provider/my-repository)
   • Replace ROLE_ARN with the ARN of the IAM Role modified above. (e.g. arn:aws:iam::123456689012:role/admin)

5. Modify the GitHub Action Workflow to obtain AWS Access Credentials

   your-repository/.github/workflows/action-name.yml:

      jobs:
        prerelease:
          runs-on: ubuntu-latest
          steps:
            - uses: actions/checkout@v2
            ...
            - uses: saml-to/assume-aws-role-action@v1
              env:
                GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
              with:
                role: "ROLE_ARN"
            ...
   

   • Replace ROLE_ARN with the ARN of the IAM Role modified above. (e.g. arn:aws:iam::123456689012:role/admin)

The ARN of the role to assume. This Role ARN must also be defined in the saml-to.yml configuration file under permissions.

The AWS Region to use. This will also be set as the AWS_DEFAULT_REGION environment variable and the region output.

Default: us-east-1

If there are multiple provider entries in the saml-to.yml configuration file, set a specific provider.

Note: If multiple providers are configured, and this is absent, the Action will fail.

Default: `` (Empty String)

Specify an alternative path to the saml-to.yml configuration file.

Store the credentials to the provided named profile in ~/.aws (instead of writing them to Environment Variables)

Default: `` (Empty String)

Default: saml-to.yml

The AWS Region authenitcated with (default: us-east-1)

Can be modified with the region input.

This will also be set in the AWS_DEFAULT_REGION environment variable.

The AWS Account ID authenticated with (e.g. 123456789012)

The ephemeral user ID (e.g. AROAYOAAAAAAAAAAAAAAA:my-repository)

The ARN of the Role.

It will be identical to the role input.

The effective ARN of the Assumed Role (e.g. arn:aws:sts::123456789012:assumed-role/admin/my-repository)

The generated AWS Access Key ID.

This is also be set in the AWS_ACCESS_KEY_ID environment variable.

The generated AWS Secret Access Key.

This is also be set in the AWS_SECRET_ACCESS_KEY environment variable.

The generated AWS Session Toke.

This is also be set in the AWS_SESSION_TOKEN environment variable.

See FAQs

• Scaffoldly
• cnuss

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• Discussions

Apache-2.0 License