## Configure AWS Credentials for GitHub Actions Configure your AWS credentials and region environment variables for use in other GitHub Actions. This action implements the AWS JavaScript SDK credential resolution chain and exports session environment variables for your other Actions to use. Environment variable exports are detected by both the AWS SDKs and the AWS CLI for AWS API calls. ## Overview API calls to AWS need to be signed with credential information, so when you use one of the AWS SDKs or an AWS tool, you must provide it with AWS credentials and and AWS region. One way to do that in GitHub Actions is to use a repository secret with IAM credentials, but this doesn't follow [AWS security guidelines](https://docs.aws.amazon.com/IAM/latest/UserGuide/security-creds.html) on using long term credentials. Instead, we recommend that you use a long term credential or JWT to fetch a temporary credential, and use that with your tools instead. This GitHub Action facilitates just that. AWS SDKs and Tools look for your credentials in standardized environment variables. In essence, this Action runs through the standard [credential resolution flow](https://docs.aws.amazon.com/sdkref/latest/guide/standardized-credentials.html), and at the end, exports environment variables for you to use later. We support five methods for fetching credentials from AWS, but we recommend that you use GitHub's OIDC provider in conjunction with a configured AWS IAM Identity Provider endpoint. For more information on how to do that, read on. ### Note about GHES Some of this documentation may be inaccurate if you are using GHES (GitHub Enterprise Server), please take note to review the GitHub documentation when relevant. For example, the URL that the OIDC JWT is issued from is different than the usual `token.actions.githubusercontent.com`, and will be unique to your enterprise server. As a result, you will need to configure this differently when you create the Identity Provider. We do not presently have a GHES testing environment to validate this action. If you are running in GHES and encounter problems, please [let us know](https://github.com/aws-actions/configure-aws-credentials/issues/new/choose). ## Security recommendations We recommend following [Amazon IAM best practices](https://docs.aws.amazon.com/IAM/latest/UserGuide/best-practices.html) for the AWS credentials used in GitHub Actions workflows, including: * Do not store credentials in your repository's code. * [Grant least privilege](https://docs.aws.amazon.com/IAM/latest/UserGuide/best-practices.html#grant-least-privilege) to the credentials used in GitHub Actions workflows. Grant only the permissions required to perform the actions in your GitHub Actions workflows. Do not assume overly permissive roles, even for testing. * [Monitor the activity](https://docs.aws.amazon.com/IAM/latest/UserGuide/best-practices.html#keep-a-log) of the credentials used in GitHub Actions workflows. * Use temporary credentials when possible. * Periodically rotate any long-term credentials you use. ## Using this action There are five different supported ways to retrieve credentials: - Using GitHub's OIDC provider (`AssumeRoleWithWebIdentity`) - Proceeding as an IAM user (No STS call is made) - Using access keys as action input (`AssumeRole`) - Using a WebIdentity Token File (`AssumeRoleWithWebIdentity`) - Using existing credentials in your runner (`AssumeRole`) Because we use the AWS JavaScript SDK, we always will use the [credential resolution flow for Node.js](https://docs.aws.amazon.com/sdk-for-javascript/v3/developer-guide/setting-credentials-node.html). Depending on your inputs, the action might override parts of this flow. We recommend using the first option above: [GitHub's OIDC provider](https://docs.github.com/en/actions/deployment/security-hardening-your-deployments/configuring-openid-connect-in-amazon-web-services). This method uses OIDC to get short-lived credentials needed for your actions. See [OIDC](#OIDC) for more information on how to setup your AWS account to assume a role with OIDC. The following table describes which method we'll use to get your credentials based on which values are supplied to the Action: | **Identity Used** | `aws-access-key-id` | `role-to-assume` | `web-identity-token-file` | `role-chaining` | `id-token` permission | --------------------------------------------------------------- | ------------------- | ---------------- | ------------------------- | - | - | | [✅ Recommended] Assume Role directly using GitHub OIDC provider | | ✔ | | | ✔ | | IAM User | ✔ | | | | | | Assume Role using IAM User credentials | ✔ | ✔ | | | | | Assume Role using WebIdentity Token File credentials | | ✔ | ✔ | | | | Assume Role using existing credentials | | ✔ | | ✔ | | *Note: `role-chaining` is not always necessary to use existing credentials. If you're getting a "Credentials loaded by the SDK do not match" error, try enabling this option.* ### Options See [action.yml](./action.yml) for more detail. | Option | Description | Required | |---------------------------|---------------------------------------------------------------------------------------------------|----------| | aws-region | Which AWS region to use | Yes | | role-to-assume | Role for which to fetch credentials. Only required for some authentication types. | No | | aws-access-key-id | AWS access key to use. Only required for some authentication types. | No | | aws-secret-access-key | AWS secret key to use. Only required for some authentication types. | No | | aws-session-token | AWS session token to use. Used in uncommon authentication scenarios. | No | | role-chaining | Use existing credentials from the environment to assume a new role. | No | | audience | The JWT audience when using OIDC. Used in non-default AWS partitions, like China regions. | No | | http-proxy | An HTTP proxy to use for API calls. | No | | mask-aws-account-id | AWS account IDs are not considered secret. Setting this will hide account IDs from output anyway. | No | | role-duration-seconds | The assumed role duration in seconds, if assuming a role. Defaults to 1 hour (3600 seconds). Acceptable values range from 15 minutes (900 seconds) to 12 hours (43200 seconds). | No | | role-external-id | The external ID of the role to assume. Only needed if your role requires it. | No | | role-session-name | Defaults to "GitHubActions", but may be changed if required. | No | | role-skip-session-tagging | Skips session tagging if set. | No | | inline-session-policy | You may further restrict the assumed role policy by defining an inline policy here. | No | | managed-session-policies | You may further restrict the assumed role policy by specifying a managed policy here. | No | | output-credentials | When set, outputs fetched credentials as action step output. (Outputs access-key-id, secret-access-key, session-token, and expiration). Defaults to false. | No | | output-env-credentials | When set, outputs fetched credentials as environment variables (AWS_REGION, AWS_DEFAULT_REGION, AWS_ACCESS_KEY_ID, AWS_SECRET_ACCESS_KEY, AWS_SESSION_TOKEN). Defaults to true. Set to false if you need to avoid setting/changing env variables. You'd probably want to use output-credentials if you disable this. (NOTE: Setting to false will prevent the aws-account-id from being exported as a step output). | No | | unset-current-credentials | When set, attempts to unset any existing credentials in your action runner. | No | | disable-retry | Disabled retry/backoff logic for assume role calls. By default, retries are enabled. | No | | retry-max-attempts | Limits the number of retry attempts before giving up. Defaults to 12. | No | | special-characters-workaround | Uncommonly, some environments cannot tolerate special characters in a secret key. This option will retry fetching credentials until the secret access key does not contain special characters. This option overrides disable-retry and retry-max-attempts. | No | | use-existing-credentials | When set, the action will check if existing credentials are valid and exit if they are. Defaults to false. | No | #### Credential Lifetime The default session duration is **1 hour**. If you would like to adjust this you can pass a duration to `role-duration-seconds`, but the duration cannot exceed the maximum that was defined when the IAM Role was created. #### External ID If your role requires an external ID to assume, you can provide the external ID with the `role-external-id` input #### Session tagging and name The default session name is "GitHubActions", and you can modify it by specifying the desired name in `role-session-name`. _Note: you might find it helpful to set the `role-session-name` to `${{ github.run_id }}` so as to clarify in audit logs which AWS actions were performed by which workflow run._ The session will be tagged with the following tags: (Refer to [GitHub's documentation for `GITHUB_` environment variable definitions](https://help.github.com/en/actions/automating-your-workflow-with-github-actions/using-environment-variables#default-environment-variables)) | Key | Value | | ---------- | ----------------- | | GitHub | "Actions" | | Repository | GITHUB_REPOSITORY | | Workflow | GITHUB_WORKFLOW | | Action | GITHUB_ACTION | | Actor | GITHUB_ACTOR | | Branch | GITHUB_REF | | Commit | GITHUB_SHA | _Note: all tag values must conform to [the tag requirements](https://docs.aws.amazon.com/STS/latest/APIReference/API_Tag.html). Particularly, `GITHUB_WORKFLOW` will be truncated if it's too long. If `GITHUB_ACTOR` or `GITHUB_WORKFLOW` contain invalid characters, the characters will be replaced with an '*'._ The action will use session tagging by default during role assumption, unless you follow our recommendation and are assuming a role with a WebIdentity. For WebIdentity role assumption, the session tags have to be included in the encoded WebIdentity token. This means that tags can only be supplied by the OIDC provider, and they cannot set during the AssumeRoleWithWebIdentity API call within the Action. See [#419](https://github.com/aws-actions/configure-aws-credentials/issues/419) for more information. You can skip this session tagging by providing `role-skip-session-tagging` as true in the action's inputs: ```yaml uses: aws-actions/configure-aws-credentials@v4 with: role-skip-session-tagging: true ``` ### Session policies Session policies are not required, but they allow you to limit the scope of the fetched credentials without making changes to IAM roles. You can specify inline session policies right in your workflow file, or refer to an existing managed session policy by its ARN. #### Inline session policies An IAM policy in stringified JSON format that you want to use as an inline session policy. Depending on preferences, the JSON could be written on a single line like this: ```yaml uses: aws-actions/configure-aws-credentials@v4 with: inline-session-policy: '{"Version":"2012-10-17","Statement":[{"Sid":"Stmt1","Effect":"Allow","Action":"s3:List*","Resource":"*"}]}' ``` Or we can have a nicely formatted JSON as well: ```yaml uses: aws-actions/configure-aws-credentials@v4.1.0 with: inline-session-policy: >- { "Version": "2012-10-17", "Statement": [ { "Sid":"Stmt1", "Effect":"Allow", "Action":"s3:List*", "Resource":"*" } ] } ``` #### Managed session policies The Amazon Resource Names (ARNs) of the IAM managed policies that you want to use as managed session policies. The policies must exist in the same account as the role. You can pass a single managed policy like this: ```yaml uses: aws-actions/configure-aws-credentials@v4.1.0 with: managed-session-policies: arn:aws:iam::aws:policy/AmazonS3ReadOnlyAccess ``` And we can pass multiple managed policies likes this: ```yaml uses: aws-actions/configure-aws-credentials@v4.1.0 with: managed-session-policies: | arn:aws:iam::aws:policy/AmazonS3ReadOnlyAccess arn:aws:iam::aws:policy/AmazonS3OutpostsReadOnlyAccess ``` ### Misc #### Adjust the retry mechanism You can now configure retry settings for when the STS call fails. By default, we retry with exponential backoff `12` times. You can disable this behavior altogether by setting the `disable-retry` input to `true`, or you can configure the number of times it retries with the `retry-max-attempts` input. #### Mask account ID Your account ID is not masked by default in workflow logs since it's not considered sensitive information. However, you can set the `mask-aws-account-id` input to `true` to mask your account ID in workflow logs if desired. #### Unset current credentials Sometimes, existing credentials in your runner can get in the way of the intended outcome. You can set the `unset-current-credentials` input to `true` to work around this issue. #### Special characters in AWS_SECRET_ACCESS_KEY Some edge cases are unable to properly parse an `AWS_SECRET_ACCESS_KEY` if it contains special characters. For more information, please see the [AWS CLI documentation](https://docs.aws.amazon.com/cli/latest/userguide/cli-chap-troubleshooting.html#tshoot-signature-does-not-match). If you set the `special-characters-workaround` option, this action will continually retry fetching credentials until we get one that does not have special characters. This option overrides the `disable-retry` and `retry-max-attempts` options. We recommend that you do not enable this option unless required, because retrying APIs infinitely until they succeed is not best practice. ## OIDC We recommend using [GitHub's OIDC provider](https://docs.github.com/en/actions/deployment/security-hardening-your-deployments/configuring-openid-connect-in-amazon-web-services) to get short-lived AWS credentials needed for your actions. When using OIDC, you configure IAM to accept JWTs from GitHub's OIDC endpoint. This action will then create a JWT unique to the workflow run using the OIDC endpoint, and it will use the JWT to assume the specified role with short-term credentials. To get this to work 1. Configure your workflow to use the `id-token: write` permission. 2. Configure your audience, if required. 3. In your AWS account, configure IAM to trust GitHub's OIDC identity provider. 4. Configure an IAM role with appropriate claim limits and permission scope. *Note*: Naming your role "GitHubActions" has been reported to not work. See [#953](https://github.com/aws-actions/configure-aws-credentials/issues/953). 5. Specify that role's ARN when setting up this action. First, in order for this action to create the JWT, your workflow file must have the `id-token: write` permission: ```yaml permissions: id-token: write contents: read ``` ### OIDC Audience When the JWT is created, an audience needs to be specified. Normally, you would use `sts.amazonaws.com`, and this action uses this by default if you don't specify one. This will work for most cases. Changing the default audience may be necessary when using non-default AWS partitions, such as China regions. You can specify the audience through the `audience` input: ```yaml - name: Configure AWS Credentials for China region audience uses: aws-actions/configure-aws-credentials@v4.1.0 with: audience: sts.amazonaws.com.cn aws-region: cn-northwest-1 role-to-assume: arn:aws-cn:iam::123456789100:role/my-github-actions-role ``` ### Configuring IAM to trust GitHub To use GitHub's OIDC provider, you must first set up federation with the provider as an IAM IdP. The GitHub OIDC provider only needs to be created once per account (i.e. multiple IAM Roles that can be assumed by the GitHub's OIDC can share a single OIDC Provider). Here is a sample CloudFormation template that will configure this trust for you. Note that the thumbprint below has been set to all F's because the thumbprint is not used when authenticating `token.actions.githubusercontent.com`. This is a special case used *only when GitHub's OIDC is authenticating to IAM*. IAM uses its library of trusted CAs to authenticate. The value is still the API, so it must be specified. You can copy the template below, or load it from here: https://d38mtn6aq9zhn6.cloudfront.net/configure-aws-credentials-latest.yml ```yaml Parameters: GitHubOrg: Description: Name of GitHub organization/user (case sensitive) Type: String RepositoryName: Description: Name of GitHub repository (case sensitive) Type: String OIDCProviderArn: Description: Arn for the GitHub OIDC Provider. Default: "" Type: String OIDCAudience: Description: Audience supplied to configure-aws-credentials. Default: "sts.amazonaws.com" Type: String Conditions: CreateOIDCProvider: !Equals - !Ref OIDCProviderArn - "" Resources: Role: Type: AWS::IAM::Role Properties: AssumeRolePolicyDocument: Statement: - Effect: Allow Action: sts:AssumeRoleWithWebIdentity Principal: Federated: !If - CreateOIDCProvider - !Ref GithubOidc - !Ref OIDCProviderArn Condition: StringEquals: token.actions.githubusercontent.com:aud: !Ref OIDCAudience StringLike: token.actions.githubusercontent.com:sub: !Sub repo:${GitHubOrg}/${RepositoryName}:* GithubOidc: Type: AWS::IAM::OIDCProvider Condition: CreateOIDCProvider Properties: Url: https://token.actions.githubusercontent.com ClientIdList: - sts.amazonaws.com ThumbprintList: - ffffffffffffffffffffffffffffffffffffffff Outputs: Role: Value: !GetAtt Role.Arn ``` ### Claims and scoping permissions To align with the Amazon IAM best practice of [granting least privilege](https://docs.aws.amazon.com/IAM/latest/UserGuide/best-practices.html#grant-least-privilege), the assume role policy document should contain a [`Condition`](https://docs.aws.amazon.com/IAM/latest/UserGuide/reference_policies_elements_condition.html) that specifies a subject (`sub`) allowed to assume the role. [GitHub also recommends](https://docs.github.com/en/actions/deployment/security-hardening-your-deployments/about-security-hardening-with-openid-connect#defining-trust-conditions-on-cloud-roles-using-oidc-claims) filtering for the correct audience (`aud`). See [AWS IAM documentation](https://docs.aws.amazon.com/IAM/latest/UserGuide/reference_policies_iam-condition-keys.html#condition-keys-wif) on which claims you can filter for in your trust policies. Without a subject (`sub`) condition, any GitHub user or repository could potentially assume the role. The subject can be scoped to a GitHub organization and repository as shown in the CloudFormation template. However, scoping it down to your org and repo may cause the role assumption to fail in some cases. See [Example subject claims](https://docs.github.com/en/actions/deployment/security-hardening-your-deployments/about-security-hardening-with-openid-connect#example-subject-claims) for specific details on what the subject value will be depending on your workflow. You can also [customize your subject claim](https://docs.github.com/en/actions/deployment/security-hardening-your-deployments/about-security-hardening-with-openid-connect#customizing-the-token-claims) if you want full control over the information you can filter for in your trust policy. If you aren't sure what your subject (`sub`) key is, you can add the [`actions-oidc-debugger`](https://github.com/github/actions-oidc-debugger) action to your workflow to see the value of the subject (`sub`) key, as well as other claims. Additional claim conditions can be added for higher specificity as explained in the [GitHub documentation](https://docs.github.com/en/actions/deployment/security-hardening-your-deployments/about-security-hardening-with-openid-connect). Due to implementation details, not every OIDC claim is presently supported by IAM. ### Further information about OIDC For further information on OIDC and GitHub Actions, please see: * [AWS docs: Creating OpenID Connect (OIDC) identity providers](https://docs.aws.amazon.com/IAM/latest/UserGuide/id_roles_providers_create_oidc.html) * [AWS docs: IAM JSON policy elements: Condition](https://docs.aws.amazon.com/IAM/latest/UserGuide/reference_policies_elements_condition.html) * [GitHub docs: About security hardening with OpenID Connect](https://docs.github.com/en/actions/deployment/security-hardening-your-deployments/about-security-hardening-with-openid-connect) * [GitHub docs: Configuring OpenID Connect in Amazon Web Services](https://docs.github.com/en/actions/deployment/security-hardening-your-deployments/configuring-openid-connect-in-amazon-web-services) * [GitHub changelog: GitHub Actions: Secure cloud deployments with OpenID Connect](https://github.blog/changelog/2021-10-27-github-actions-secure-cloud-deployments-with-openid-connect/) ## Self-Hosted Runners If you run your GitHub Actions in a [self-hosted runner](https://help.github.com/en/actions/hosting-your-own-runners/about-self-hosted-runners) that already has access to AWS credentials, such as an EC2 instance, then you do not need to provide IAM user access key credentials to this action. We will use the standard AWS JavaScript SDK credential resolution methods to find your credentials, so if the AWS JS SDK can authenticate on your runner, this Action will as well. If no access key credentials are given in the action inputs, this action will use credentials from the runner environment using the [default methods for the AWS SDK for Javascript](https://docs.aws.amazon.com/sdk-for-javascript/v3/developer-guide/setting-credentials-node.html). You can use this action to simply configure the region and account ID in the environment, and then use the runner's credentials for all AWS API calls made by your Actions workflow: ```yaml uses: aws-actions/configure-aws-credentials@v4.1.0 with: aws-region: us-east-2 ``` In this case, your runner's credentials must have permissions to call any AWS APIs called by your Actions workflow. Or, you can use this action to assume a role, and then use the role credentials for all AWS API calls made by your Actions workflow: ```yaml uses: aws-actions/configure-aws-credentials@v4.1.0 with: aws-region: us-east-2 role-to-assume: my-github-actions-role ``` In this case, your runner's credentials must have permissions to assume the role. You can also assume a role using a web identity token file, such as if using [Amazon EKS IRSA](https://docs.aws.amazon.com/eks/latest/userguide/iam-roles-for-service-accounts-technical-overview.html). Pods running in EKS worker nodes that do not run as root can use this file to assume a role with a web identity. ### Proxy Configuration If need use a HTTP proxy you can set it in the action manually. Additionally this action will always consider the `HTTP_PROXY` environment variable. Manually configured proxy: ```yaml uses: aws-actions/configure-aws-credentials@v4.1.0 with: aws-region: us-east-2 role-to-assume: my-github-actions-role http-proxy: "http://companydomain.com:3128" ``` Proxy configured in the environment variable: ```bash # Your environment configuration HTTP_PROXY="http://companydomain.com:3128" ``` ### Use with the AWS CLI This workflow does _not_ install the [AWS CLI](https://aws.amazon.com/cli/) into your environment. Self-hosted runners that intend to run this action prior to executing `aws` commands need to have the AWS CLI [installed](https://docs.aws.amazon.com/cli/latest/userguide/cli-chap-install.html) if it's not already present. Most [GitHub hosted runner environments](https://github.com/actions/virtual-environments) should include the AWS CLI by default. ## Examples ### AssumeRoleWithWebIdentity (recommended) ```yaml - name: Configure AWS Credentials uses: aws-actions/configure-aws-credentials@v4.1.0 with: aws-region: us-east-2 role-to-assume: arn:aws:iam::123456789100:role/my-github-actions-role role-session-name: MySessionName ``` In this example, the Action will load the OIDC token from the GitHub-provided environment variable and use it to assume the role `arn:aws:iam::123456789100:role/my-github-actions-role` with the session name `MySessionName`. ### AssumeRole with role previously assumed by action in same workflow ```yaml - name: Configure AWS Credentials uses: aws-actions/configure-aws-credentials@v4.1.0 with: aws-region: us-east-2 role-to-assume: arn:aws:iam::123456789100:role/my-github-actions-role role-session-name: MySessionName - name: Configure other AWS Credentials uses: aws-actions/configure-aws-credentials@v4.1.0 with: aws-region: us-east-2 role-to-assume: arn:aws:iam::987654321000:role/my-second-role role-session-name: MySessionName role-chaining: true ``` In this two-step example, the first step will use OIDC to assume the role `arn:aws:iam::123456789100:role/my-github-actions-role` just as in the prior example. Following that, a second step will use this role to assume a different role, `arn:aws:iam::987654321000:role/my-second-role`. ### AssumeRole with static IAM credentials in repository secrets ```yaml - name: Configure AWS Credentials uses: aws-actions/configure-aws-credentials@v4.1.0 with: aws-access-key-id: ${{ secrets.AWS_ACCESS_KEY_ID }} aws-secret-access-key: ${{ secrets.AWS_SECRET_ACCESS_KEY }} aws-region: us-east-2 role-to-assume: ${{ secrets.AWS_ROLE_TO_ASSUME }} role-external-id: ${{ secrets.AWS_ROLE_EXTERNAL_ID }} role-duration-seconds: 1200 role-session-name: MySessionName ``` In this example, the secret `AWS_ROLE_TO_ASSUME` contains a string like `arn:aws:iam::123456789100:role/my-github-actions-role`. To assume a role in the same account as the static credentials, you can simply specify the role name, like `role-to-assume: my-github-actions-role`. ### Retrieving credentials from step output, AssumeRole with temporary credentials ```yaml - name: Configure AWS Credentials 1 id: creds uses: aws-actions/configure-aws-credentials@v4.1.0 with: aws-region: us-east-2 role-to-assume: arn:aws:iam::123456789100:role/my-github-actions-role output-credentials: true - name: get caller identity 1 run: | aws sts get-caller-identity - name: Configure AWS Credentials 2 uses: aws-actions/configure-aws-credentials@v4.1.0 with: aws-region: us-east-2 aws-access-key-id: ${{ steps.creds.outputs.aws-access-key-id }} aws-secret-access-key: ${{ steps.creds.outputs.aws-secret-access-key }} aws-session-token: ${{ steps.creds.outputs.aws-session-token }} role-to-assume: arn:aws:iam::123456789100:role/my-other-github-actions-role - name: get caller identity2 run: | aws sts get-caller-identity ``` This example shows that you can reference the fetched credentials as outputs if `output-credentials` is set to true. This example also shows that you can use the `aws-session-token` input in a situation where session tokens are fetched and passed to this action. ## License Summary This code is made available under the MIT license. ## Security Disclosures If you would like to report a potential security issue in this project, please do not create a GitHub issue. Instead, please follow the instructions [here](https://aws.amazon.com/security/vulnerability-reporting/) or [email AWS security directly](mailto:aws-security@amazon.com).