The security plugin can integrate with identify providers that use the OpenID Connect standard. This feature enables the following:
* Automatic configuration
Point the security plugin to the metadata of your identity provider (IdP), and the security plugin uses that data for configuration.
* Automatic key fetching
The security plugin automatically retrieves the public key for validating the JSON web tokens (JWTs) from the JSON web key set (JWKS) endpoint of your IdP. You don't have to configure keys or shared secrets in `config.yml`.
* Key rollover
You can change the keys used for signing the JWTs directly in your IdP. If the security plugin detects an unknown key, it tries to retrieve it from the IdP. This rollover is transparent to the user.
* OpenSearch Dashboards single sign-on
## Configure OpenID Connect integration
To integrate with an OpenID IdP, set up an authentication domain and choose `openid` as the HTTP authentication type. JSON web tokens already contain all required information to verify the request, so set `challenge` to `false` and `authentication_backend` to `noop`.
The following table shows the configuration parameters.
Name | Description
:--- | :---
`openid_connect_url` | The URL of your IdP where the security plugin can find the OpenID Connect metadata/configuration settings. This URL differs between IdPs. Required.
`jwt_header` | The HTTP header that stores the token. Typically the `Authorization` header with the `Bearer` schema: `Authorization: Bearer <token>`. Optional. Default is `Authorization`.
`jwt_url_parameter` | If the token is not transmitted in the HTTP header, but as an URL parameter, define the name of the parameter here. Optional.
`subject_key` | The key in the JSON payload that stores the user's name. If not defined, the [subject](https://tools.ietf.org/html/rfc7519#section-4.1.2) registered claim is used. Most IdP providers use the `preferred_username` claim. Optional.
`roles_key` | The key in the JSON payload that stores the user's roles. The value of this key must be a comma-separated list of roles. Required only if you want to use roles in the JWT.
## OpenID Connect URL
OpenID Connect specifies various endpoints for integration purposes. The most important endpoint is `well-known`, which lists endpoints and other configuration options for the security plugin.
The URL differs between IdPs, but usually ends in `/.well-known/openid-configuration`.
The main information that the security plugin needs is `jwks_uri`. This URI specifies where the IdP's public keys in JWKS format can be found. For example:
As per the [OpenID Connect specification](https://openid.net/specs/openid-connect-messages-1_0-20.html), the `kid` (key ID) is mandatory. Token verification does not work if an IdP fails to add the `kid` field to the JWT.
If the security plugin receives a JWT with an unknown `kid`, it visits the IdP's `jwks_uri` and retrieves all available, valid keys. These keys are used and cached until a refresh is triggered by retrieving another unknown key ID.
## Key rollover and multiple public keys
The security plugin can maintain multiple valid public keys at once. The OpenID specification does not allow for a validity period of public keys, so a key is valid until it has been removed from the list of valid keys in your IdP and the list of valid keys has been refreshed.
If you want to roll over a key in your IdP, follow these best practices:
- Create a new key pair in your IdP, and give the new key a higher priority than the currently used key.
Your IdP uses this new key over the old key.
- Upon first appearance of the new `kid` in a JWT, the security plugin refreshes the key list.
At this point, both the old key and the new key are valid. Tokens signed with the old key are also still valid.
- The old key can be removed from your IdP when the last JWT signed with this key has timed out.
If you have to immediately change your public key, you can also delete the old key first and then create a new one. In this case, all JWTs signed with the old key become invalid immediately.
## TLS settings
To prevent man-in-the-middle attacks, you should secure the connection between the security plugin and your IdP with TLS.
### Enabling TLS
Use the following parameters to enable TLS for connecting to your IdP:
`pemtrustedcas_filepath` | Absolute path to the PEM file containing the root CAs of your IdP.
`pemtrustedcas_content` | The root CA content of your IdP. Cannot be used if `pemtrustedcas_filepath` is set.
### TLS client authentication
To use TLS client authentication, configure the PEM certificate and private key the security plugin should send for TLS client authentication (or its content):
`enable_ssl_client_auth` | Whether to send the client certificate to the IdP server. Default is false.
`pemcert_filepath` | Absolute path to the client certificate.
`pemcert_content` | The content of the client certificate. Cannot be used when `pemcert_filepath` is set.
`pemkey_filepath` | Absolute path to the file containing the private key of the client certificate.
`pemkey_content` | The content of the private key of your client certificate. Cannot be used when `pemkey_filepath` is set.
`pemkey_password` | The password of your private key, if any.
### Enabled ciphers and protocols
You can limit the allowed ciphers and TLS protocols by using the following keys.
Name | Description
:--- | :---
`enabled_ssl_ciphers` | Array. Enabled TLS cipher suites. Only Java format is supported.
`enabled_ssl_protocols` | Array. Enabled TLS protocols. Only Java format is supported.
## (Advanced) DoS protection
To help protect against denial-of-service (DoS) attacks, the security plugin only allows a maximum number of new key IDs in a certain span of time. If the number of new key IDs exceeds this threshold, the security plugin returns HTTP status code 503 (Service Unavailable) and refuses to query the IdP. By default, the security plugin does not allow for more than 10 unknown key IDs within 10 seconds. The following table shows how to modify these settings.
Name | Description
:--- | :---
`refresh_rate_limit_count` | The maximum number of unknown key IDs in the time frame. Default is 10.
`refresh_rate_limit_time_window_ms` | The time frame to use when checking the maximum number of unknown key IDs, in milliseconds. Default is 10000 (10 seconds).
## OpenSearch Dashboards single sign-on
Activate OpenID Connect by adding the following to `opensearch_dashboards.yml`:
OpenID Connect providers usually publish their configuration in JSON format under the *metadata url*. Therefore, most settings can be pulled in automatically, so the OpenSearch Dashboards configuration becomes minimal. The most important settings are the following:
- [Connect URL](#openid-connect-url)
- Client ID
Every IdP can host multiple clients (sometimes called applications) with different settings and authentication protocols. When enabling OpenID Connect, you should create a new client for OpenSearch Dashboards in your IdP. The client ID uniquely identifies OpenSearch Dashboards.
- Client secret
Beyond the ID, each client also has a client secret assigned. The client secret is usually generated when the client is created. Applications can obtain an identity token only when they provide a client secret. You can find this secret in the settings of the client on your IdP.
`opensearch_security.openid.connect_url` | The URL where the IdP publishes the OpenID metadata. Required.
`opensearch_security.openid.client_id` | The ID of the OpenID Connect client configured in your IdP. Required.
`opensearch_security.openid.client_secret` | The client secret of the OpenID Connect client configured in your IdP. Required.
`opensearch_security.openid.scope` | The [scope of the identity token](https://auth0.com/docs/scopes/current) issued by the IdP. Optional. Default is `openid profile email address phone`.
`opensearch_security.openid.header` | HTTP header name of the JWT token. Optional. Default is `Authorization`.
`opensearch_security.openid.logout_url` | The logout URL of your IdP. Optional. Only necessary if your IdP does not publish the logout URL in its metadata.
`opensearch_security.openid.base_redirect_url` | The base of the redirect URL that will be sent to your IdP. Optional. Only necessary when OpenSearch Dashboards is behind a reverse proxy, in which case it should be different than `server.host` and `server.port` in `opensearch_dashboards.yml`.
Because OpenSearch Dashboards requires that the internal OpenSearch Dashboards server user can authenticate through HTTP basic authentication, you must configure two authentication domains. For OpenID Connect, the HTTP basic domain has to be placed first in the chain. Make sure you set the challenge flag to `false`.
Modify and apply the following example settings in `config.yml`:
