sftpgo-mirror/docs/oidc.md

OpenID Connect

OpenID Connect integration allows you to map your identity provider users to SFTPGo admins/users and so you can login to SFTPGo Web Client and Web Admin user interfaces using your identity provider.

SFTPGo allows to configure per-binding OpenID Connect configurations. The supported configuration parameters are documented within the oidc section here.

Let's see a basic integration with the Keycloak identify provider. Other OpenID connect compatible providers should work by configuring them in a similar way.

We'll not go through the complete process of creating a realm/clients/users in Keycloak. You can look this up here.

Here is just an outline:

• create a realm named sftpgo
• in "Realm Settings" -> "Login" adjust the "Require SSL" setting as per your requirements
• create a client named sftpgo-client
• for the sftpgo-client set the Access Type to confidential and a valid redirect URI, for example if your SFTPGo instance is running on http://192.168.1.50:8080 a valid redirect URI is http://192.168.1.50:8080/*
• for the sftpgo-client, in the Mappers settings, make sure that the username and the sftpgo role are added to the ID token. For example you can add the user attribute sftpgo_role as JSON string to the ID token and the username as preferred_username JSON string to the ID token
• for your users who need to be mapped as SFTPGo administrators add a custom attribute specifying sftpgo_role as key and admin as value

The resulting JSON configuration for the sftpgo-client that you can obtain from the "Installation" tab is something like this:

{
  "realm": "sftpgo",
  "auth-server-url": "http://192.168.1.12:8086/auth/",
  "ssl-required": "none",
  "resource": "sftpgo-client",
  "credentials": {
    "secret": "jRsmE0SWnuZjP7djBqNq0mrf8QN77j2c"
  },
  "confidential-port": 0
}

Add the following configuration parameters to the SFTPGo configuration file (or use env vars to set them):

...
    "oidc": {
      "client_id": "sftpgo-client",
      "client_secret": "jRsmE0SWnuZjP7djBqNq0mrf8QN77j2c",
      "config_url": "http://192.168.1.12:8086/auth/realms/sftpgo",
      "redirect_base_url": "http://192.168.1.50:8080",
      "username_field": "preferred_username",
      "role_field": "sftpgo_role",
      "implicit_roles": false,
      "custom_fields": []
    }
...

SFTPGo will automatically add the /.well-known/openid-configuration suffix to the provided config_url and uses OpenID Connect Discovery specifications to obtain information needed to interact with it, including its OAuth 2.0 endpoint locations.

From SFTPGo login page click Login with OpenID button, you will be redirected to the Keycloak login page, after a successful authentication Keyclock will redirect back to SFTPGo Web Admin or SFTPGo Web Client.

Please note that the ID token returned from Keycloak must contain the username_field specified in the SFTPGo configuration and optionally the role_field. The mapped usernames must exist in SFTPGo. If you don't want to explicitly define SFTPGo roles in your identity provider, you can set implicit_roles to true. With this configuration, the SFTPGo role is assumed based on the login link used.

Here is an example ID token which allows the SFTPGo admin root to access to the Web Admin UI.

{
    "exp": 1644758026,
    "iat": 1644757726,
    "auth_time": 1644757647,
    "jti": "c6cf172d-08d6-41cf-8e5d-20b7ac0b8011",
    "iss": "http://192.168.1.12:8086/auth/realms/sftpgo",
    "aud": "sftpgo-client",
    "sub": "48b0de4b-3090-4315-bbcb-be63c48be1d2",
    "typ": "ID",
    "azp": "sftpgo-client",
    "nonce": "XLxfYDhMmWwiYctgLTCZjC",
    "session_state": "e20ab97c-d3a9-4e53-872d-09d104cbd286",
    "at_hash": "UwubF1W8H0XItHU_DIpjfQ",
    "acr": "0",
    "sid": "e20ab97c-d3a9-4e53-872d-09d104cbd286",
    "email_verified": false,
    "preferred_username": "root",
    "sftpgo_role": "admin"
}

And the following is an example ID token which allows the SFTPGo user user1 to access to the Web Client UI.

{
    "exp": 1644758183,
    "iat": 1644757883,
    "auth_time": 1644757647,
    "jti": "939de932-f941-4b04-90fc-7071b7cc6b10",
    "iss": "http://192.168.1.12:8086/auth/realms/sftpgo",
    "aud": "sftpgo-client",
    "sub": "48b0de4b-3090-4315-bbcb-be63c48be1d2",
    "typ": "ID",
    "azp": "sftpgo-client",
    "nonce": "wxcWPPi3H7ktembUdeToqQ",
    "session_state": "e20ab97c-d3a9-4e53-872d-09d104cbd286",
    "at_hash": "RSDpwzVG_6G2haaNF0jsJQ",
    "acr": "0",
    "sid": "e20ab97c-d3a9-4e53-872d-09d104cbd286",
    "email_verified": false,
    "preferred_username": "user1"
}

SFTPGo users (not admins) can be created/updated after successful OpenID authentication by defining a pre-login hook. You can use the custom_fields configuration parameter to define the token claims field names to pass to the pre-login hook, these fields are useful for implementing custom logic when creating/updating the SFTPGo user within the hook. For example you can set the field sftpgo_home_dir in your identity provider and add it to the custom_fields in the SFTPGo configuration like this:

...
    "oidc": {
      "client_id": "sftpgo-client",
      "client_secret": "jRsmE0SWnuZjP7djBqNq0mrf8QN77j2c",
      "config_url": "http://192.168.1.12:8086/auth/realms/sftpgo",
      "redirect_base_url": "http://192.168.1.50:8080",
      "username_field": "preferred_username",
      "role_field": "sftpgo_role",
      "custom_fields": ["sftpgo_home_dir"]
    }
...

The pre-login hook will receive a JSON serialized user with the following field:

...
  "oidc_custom_fields": {
    "sftpgo_home_dir": "configured value"
  },
...