sftpgo/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",
      "custom_fields": []
    }
...

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.

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"
  },
...