aws-cli-oidc

CLI tool for retrieving AWS temporary credentials using an OIDC provider.

This is a fork of https://github.com/openstandia/aws-cli-oidc, updated with:

• AWS SDK for Go v2
• GitHub Dependabot
• golangci-lint
• many other improvements

How does it work?

AWS Identity Providers and Federation supports IdPs that are compatible with OpenID Connect (OIDC) or SAML 2.0 (Security Assertion Markup Language 2.0). This tool works with both types of IdP if it supports OIDC because it works as OIDC client. If the federation between the AWS account and the IdP is established, and an OIDC client for this tool is registered in the IdP, you can get AWS temporary credentials via standard browser login. It means you don't need to pass your credential of the IdP to this tool.

Please refer the following diagrams how it works.

Federation type: OIDC

Federation type: SAML 2.0

Note: The OIDC provider must support OAuth 2.0 Token Exchange for exchanging access token/ID token and SAML2 assertion.

Prerequisite AWS and OIDC provider settings before using this tool

Before using this tool, the system administrator need to setup the following configuration.

• Identity Federation using SAML2/OIDC between AWS and the OIDC provider. See https://docs.aws.amazon.com/IAM/latest/UserGuide/id_roles_providers.html.
• Registration OIDC/OAuth2 client for this CLI tool in the OIDC provider. Note: The OIDC provider must allow any port to be specified at the time of the request for loopback IP redirect URIs because this tool follows RFC 8252 OAuth 2.0 for Native Apps 7.3 Loopback Interface Redirection.

Also depending on the federation type between AWS and the OIDC provider, requirements for the OIDC providers will change.

Federation type: OIDC

• The OIDC provider only needs to support OIDC. SAML2 and OAuth 2.0 Token Exchange are not necessary. Very simple.
• However, the JWKS endpoint of the OIDC provider needs to exported to the Internet for AWS to access the endpoint. This is required to obtain the public key and to verify the ID token which is issued by the IdP.

Federation type: SAML 2.0

• Of course, the OIDC provider must support not only OIDC but also SAML2 for federation between itself and AWS.
• The OIDC provider must support OAuth 2.0 Token Exchange for exchanging access token/ID token and SAML2 assertion. aws-cli-oidc gets access token/ID token from the OIDC provider first, then it needs to get SAML2 assertion from the provider which is required for getting AWS temporary credentials using AWS STS API.

Tested OIDC Provider

OIDC Provider	OIDC	SAML2
Google account	OK	-
Keycloak	OK	OK (Note 1)
Dex IdP	OK	Not tested

• Note 1: You need to use Keycloak 12 or higher that supports exchanging from access token to SAML2 assertion. Also, you need to enable Token Exchange feature.

Install

Download from Releases page.

Usage

CLI tool for retrieving AWS temporary credentials using OIDC provider

Usage:
  aws-cli-oidc [command]

Available Commands:
  clear-secret Clear OS secret store that saves AWS credentials
  completion   Generate the autocompletion script for the specified shell
  get-cred     Get AWS credentials and out to stdout
  help         Help about any command
  setup        Interactive setup of aws-cli-oidc

Flags:
  -h, --help      help for aws-cli-oidc
  -v, --version   version for aws-cli-oidc

Use "aws-cli-oidc [command] --help" for more information about a command.

Setup

Use aws-cli-oidc setup command and follow the guide.

Get AWS temporary credentials

Use aws-cli-oidc get-cred -p <your oidc provider name> command. It opens your browser. Now you can see the login page which the OIDC provider offers. Then do login. If successful, AWS temporary credentials will be shown as below.

aws-cli-oidc get-cred -p myop
Using config file: /home/wadahiro/.aws-cli-oidc/config.yaml
Login successful!
Selected role: arn:aws:iam::123456789012:role/developer
PrincipalARN: arn:aws:iam::123456789012:saml-provider/myop
RoleARN: arn:aws:iam::123456789012:role/developer

export AWS_ACCESS_KEY_ID=ASIAT......
export AWS_SECRET_ACCESS_KEY=9bkS0whPelMYQ.......
export AWS_SESSION_TOKEN=FQoGZXIvYXdzENz.......

Integrate aws-cli

Sourcing credentials with an external process describes how to integrate aws-cli with external tool. You can use aws-cli-oidc as the external process.

For example, if your IdP, myop, has been setup as an Identity Provider in the 123456789012 account, and the arn:aws:iam::123456789012:role/developer is configured to allow AssumeRoleWithWebIdentity from your IdP, you can authenticate with the myop provider, assuming the arn:aws:iam::123456789012:role/developer role for 12 hours, with an entry in your .aws/config file similar to:

[profile foo-developer]
credential_process=aws-cli-oidc get-cred -p myop -r arn:aws:iam::123456789012:role/developer -j -s -d 43200

Then, AWS CLI should work:

$ AWS_PROFILE=foo-developer aws sts get-caller-identity
{
    "UserId": "AROA1T2W4XNSWEI3BS69H:aws-cli-oidc",
    "Account": "123456789012",
    "Arn": "arn:aws:sts::123456789012:assumed-role/developer/aws-cli-oidc"
}

Using the -s option, the AWS temporary credentials will be saved into your OS secret store. The next call to aws-cli-oidc with -s will attempt to reuse these credentials.

Bugs?

Please report them via https://github.com/stensonb/aws-cli-oidc/issues

Building and Releasing

You must have goreleaser installed and in your executable path.

Building

make build

Releasing

1. update Makefile on main:
   1. update Makefile VERSION (honoring semver)
   2. submit PR
   3. commit to main
2. create tag and release binaries: make release

Licence

Licensed under the MIT license.

Authors

• Bryan Stenson
• Hiroyuki Wada - github.com/wadahiro/aws-cli-oidc