Active Directory / LDAP External Identity Management

Overview

MinIO supports using an Active Directory or LDAP (AD/LDAP) service for external management of user identities. Configuring an external IDentity Provider (IDP) enables Single-Sign On (SSO) workflows, where applications authenticate against the external IDP before accessing MinIO.

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 AD/LDAP provider must specify the necessary policies as part of the user profile data. See Access Control for AD/LDAP Managed Identities for more information.

See Configure MinIO for Authentication using Active Directory / LDAP for instructions on enabling external identity management using an AD/LDAP service.

MinIO Supports At Most One Configured IDentity Provider

Configuring an external IDP disables the MinIO internal IDP and prevents the configuration of any other external IDP.

The external IDP must have at least one configured user identity with the required policy claims. If no such user exists, the MinIO server is effectively inaccessible outside of using the root user.

Authentication and Authorization Flow

The login flow for an application using Active Directory / LDAP credentials is as follows:

  1. Specify the AD/LDAP credentials to the MinIO Security Token Service (STS) AssumeRoleWithLDAPIdentity API endpoint.

  2. MinIO verifies the provided credentials against the AD/LDAP server.

  3. MinIO checks for any policy whose name matches the user Distinguished Name (DN) and assigns that policy to the authenticated user.

    If configured to perform group queries, MinIO also queries for a list of AD/LDAP groups in which the user has membership. MinIO checks for any policy whose name matches a returned group DN and assigns that policy to the authenticated user.

  4. 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 whose name matches either the authenticated user DN or a group DN.

MinIO provides an example Go application ldap.go that handles the full login flow.

AD/LDAP users can alternatively create service accounts associated to their AD/LDAP user Distinguished Name. 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. Use either of the following methods to create a new service account

  • Log into the MinIO Console using the AD/LDAP-managed user credentials. From the Identity section of the left navigation, select Service Accounts followed by the Create service account + button.

  • Use the mc admin user svcacct add command to create the service account. Specify the user Distinguished Name as the username to which to associate the service account.

Querying the Active Directory / LDAP Service

MinIO queries the configured Active Directory / LDAP server to verify the credentials specified by the application and optionally return a list of groups in which the user has membership. MinIO supports two modes for performing these queries:

  • Lookup-Bind Mode - Use a special read-only account for querying the LDAP server.

  • Username-Bind Mode - Use the credentials specified by the application to login to the LDAP server.

MinIO recommends using Lookup-Bind mode as the preferred method for verifying AD/LDAP credentials. Username-Bind mode is a legacy method retained for backwards compatibility only.

Lookup-Bind Mode

In Lookup-Bind mode, MinIO uses a read-only AD/LDAP account with the minimum privileges required to authenticate to the AD/LDAP server and perform user and group lookups.

The following tabs provide a reference of the environment variables and configuration settings required for enabling Lookup-Bind mode.

See the identity_ldap reference documentation for more information on these settings. The Configure MinIO for Authentication using OpenID tutorial includes complete instructions on setting these variables.

Lookup-Bind is incompatible and mutually exclusive with Username-Bind Mode.

Username-Bind Mode

In Username-Bind mode, MinIO uses the AD/LDAP credentials provided by the client attempting authentication to login to the AD/LDAP server and perform and group lookups.

Username-Bind mode is preserved for compatibility only. MinIO recommends using Lookup-Bind Mode wherever possible.

The following tabs provide a reference of the environment variables and configuration settings required for enabling Username-Bind mode.

See the Active Directory / LDAP Identity Management reference documentation for more information on this variable.

See the identity_ldap reference documentation for more information on this setting.

Username-bind is incompatible and mutually exclusive with Lookup-Bind Mode.

Access Control for Externally Managed Identities

MinIO uses Policy Based Access Control (PBAC) to define the actions and resources to which an authenticated user has access. When using an Active Directory/LDAP server for identity management (authentication), MinIO maintains control over access (authorization) through PBAC.

When a user successfully authenticates to MinIO using their AD/LDAP credentials, MinIO searches for all policies which are explicitly associated to that user’s Distinguished Name (DN). Specifically, the policy must be assigned to a user with a matching DN using the mc admin policy set command.

For example, consider the following policy assignments:

mc admin policy set --consoleAdmin user='cn=sisko,cn=users,dc=example,dc=com'
mc admin policy set --readwrite,diagnostics user='cn=dax,cn=users,dc=example,dc=com'
  • MinIO would assign an authenticated user with DN matching cn=sisko,cn=users,dc=example,dc=com the consoleAdmin policy, granting complete access to the MinIO server.

  • MinIO would assign an authenticated user with DN matching cn=dax,cn=users,dc=example,dc=com both the readwrite and diagnostics policies, granting general read/write access to the MinIO server and access to diagnostic administrative operations.

  • MinIO would assign no policies to an authenticated user with DN matching cn=quark,cn=users,dc=example,dc=com and deny all access to API operations.

MinIO also supports querying for the user’s AD/LDAP group membership. MinIO attempts to match existing policies to the DN for each of the user’s groups. The authenticated users complete set of permissions consists of its explicitly assigned and group-inherited policies. See Group Lookup for more information.

MinIO uses deny-by-default behavior where a user with no explicitly assigned or group-inherited policies cannot access any resource on the MinIO deployment.

MinIO provides built-in policies for basic access control. You can create new policies using the mc admin policy command.

Group Lookup

MinIO supports querying the Active Directory / LDAP server for a list of groups in which the authenticated user has membership. MinIO attempts to match existing policies to each group DN and assigns each matching policy to the authenticated user.

For example, consider the following policy assignments:

mc admin policy set --consoleAdmin group='cn=ops,cn=groups,dc=example,dc=com'
mc admin policy set --diagnostics group='cn=engineering,cn=groups,dc=example,dc=com'
  • MinIO would assign any authenticating user with membership in the cn=ops,cn=groups,dc=example,dc=com AD/LDAP group the consoleAdmin policy, granting complete access to the MinIO server.

  • MinIO would assign any authenticating user with membership in the cn=engineering,cn=groups,dc=example,dc=com AD/LDAP group the diagnostics policy, granting access to diagnostic administrative operations.

The following tabs provide a reference of the environment variables and configuration settings required for enabling group lookups:

See the Active Directory / LDAP Identity Management reference documentation for more information on these variables. The Configure MinIO for Authentication using Active Directory / LDAP tutorial includes complete instructions on setting these values.

See the identity_ldap reference documentation for more information on these settings. The Configure MinIO for Authentication using Active Directory / LDAP tutorial includes complete instructions on setting these variables.