OpenID Connect Access Management

Table of Contents

Authentication and Authorization Flow
Identifying the JWT Claim Value
Creating Policies to Match Claims

MinIO supports using an OpenID Connect (OIDC) compatible IDentity Provider (IDP) such as Okta, KeyCloak, Dex, Google, or Facebook for external management of user identities.

For identities managed by the external OpenID Connect (OIDC) compatible provider, MinIO uses the JSON Web Token claim returned as part of the OIDC authentication flow to identify the policies to assign to the authenticated user.

MinIO by default denies access to all actions or resources not explicitly allowed by a user’s assigned or inherited policies. Users managed by an OIDC provider must specify the necessary policies as part of the JWT claim. If the user JWT claim has no matching MinIO policies, that user has no permissions to access any action or resource on the MinIO deployment.

The specific claim which MinIO looks for is configured as part of deploying the cluster with OIDC identity management. This page focuses on creating MinIO policies to match the configured OIDC claims.

Authentication and Authorization Flow

The login flow for an application using OIDC credentials is as follows:

Authenticate to the configured OIDC provider and retrieve a JSON Web Token (JWT).

MinIO only supports the OpenID Authorization Code Flow. Authentication using Implicit Flow is not supported.
Specify the JWT to the MinIO Security Token Service (STS) AssumeRoleWithWebIdentity API endpoint.

MinIO verifies the JWT against the configured OIDC provider.

If the JWT is valid, MinIO checks for a claim specifying a list of one or more policies to assign to the authenticated user. MinIO defaults to checking the policy claim.
MinIO returns temporary credentials in the STS API response in the form of an access key, secret key, and session token. The credentials have permissions matching those policies specified in the JWT claim.
Applications use the temporary credentials returned by the STS endpoint to perform authenticated S3 operations on MinIO.

MinIO provides an example Go application web-identity.go that handles the full login flow.

OIDC users can alternatively create service accounts associated to their AD/LDAP user. Service accounts are long-lived credentials which inherit their privileges from the parent user. The parent user can further restrict those privileges while creating the service account. To create a new service account, log into the MinIO Console using the OIDC-managed user credentials. From the Identity section of the left navigation, select Service Accounts followed by the Create service account + button.

Identifying the JWT Claim Value

MinIO uses the JWT token returned as part of the OIDC authentication flow to identify the specific policies to assign to the authenticated user.

You can use a JWT Debugging tool to decode the returned JWT token and validate that the user attributes include the required claims.

See RFC 7519: JWT Claim for more information on JWT claims.

Defer to the documentation for your preferred OIDC provider for instructions on configuring user claims.

Creating Policies to Match Claims

Use either the MinIO Console or the mc admin policy command to create policies that match one or more claim values: