The Security plugin supports user authentication through SAML single sign-on. The Security plugin implements the web browser SSO profile of the SAML 2.0 protocol.
This profile is meant for use with web browsers. It is not a general-purpose way of authenticating users against the Security plugin, so its primary use case is to support OpenSearch Dashboards single sign-on.
1. Visit the [saml-demo branch](https://github.com/opensearch-project/demos/tree/saml-demo) of the demos repository and download it to a folder of your choice. If you're not familiar with how to use GitHub, see the [OpenSearch onboarding guide](https://github.com/opensearch-project/demos/blob/main/ONBOARDING.md) for instructions.
1. Navigate to the `demo` folder:
```zsh
$ cd <path-to-demos-folder>/demo
```
1. Review the following files, as needed:
*`.env`:
* Defines the OpenSearch and OpenSearch Dashboards version to use. The default is the latest version ({{site.opensearch_major_minor_version}}).
* Defines the `OPENSEARCH_INITIAL_ADMIN_PASSWORD` variable required by versions 2.12 and later.
*`./custom-config/opensearch_dashboards.yml`: Includes the SAML settings for the default `opensearch_dashboards.yml` file.
*`./custom-config/config.yml`: Configures SAML for authentication.
*`docker-compose.yml`: Defines an OpenSearch server node, an OpenSearch Dashboards server node, and a SAML server node.
*`./saml/config/authsources.php`: Contains the list of users that can be authenticated by this SAML domain.
1. From the command line, run:
```zsh
$ docker-compose up.
```
1. Access OpenSearch Dashboards at [http://localhost:5601](http://localhost:5601){:target='\_blank'}.
1. Select `Log in with single sign-on`. This redirects you to the SAML login page.
1. Log in to OpenSearch Dashboards with a user defined in `./saml/config/authsources.php` (such as `user1` with password `user1pass`).
1. After logging in, note that the user ID shown in the upper-right corner of the screen is the same as the `NameID` attribute for the user defined in `./saml/config/authsources.php` of the SAML server (that is, `saml-test` for `user1`).
1. If you want to examine the SAML server, run `docker ps` to find its container ID and then `docker exec -it <container-id> /bin/bash`.
In particular, you might find it helpful to review the contents of the `/var/www/simplesamlphp/config/` and `/var/www/simplesamlphp/metadata/` directories.
To use SAML for authentication, you need to configure a respective authentication domain in the `authc` section of `config/opensearch-security/config.yml`. Because SAML works solely on the HTTP layer, you do not need any `authentication_backend` and can set it to `noop`. Place all SAML-specific configuration options in this chapter in the `config` section of the SAML HTTP authenticator:
After you have configured SAML in `config.yml`, you must also [activate it in OpenSearch Dashboards](#opensearch-dashboards-configuration).
## Running multiple authentication domains
We recommend adding at least one other authentication domain, such as LDAP or the internal user database, to support API access to OpenSearch without SAML. For OpenSearch Dashboards and the internal OpenSearch Dashboards server user, you also must add another authentication domain that supports basic authentication. This authentication domain should be placed first in the chain, and the `challenge` flag must be set to `false`:
A SAML identity provider (IdP) provides a SAML 2.0 metadata file describing the IdP's capabilities and configuration. The Security plugin can read IdP metadata either from a URL or a file. The choice that you make depends on your IdP and your preferences. The SAML 2.0 metadata file is required.
`idp.metadata_file` | The path to the SAML 2.0 metadata file of your IdP. Place the metadata file in the `config` directory of OpenSearch. The path has to be specified relative to the `config` directory. Required if `idp.metadata_url` is not set.
`idp.metadata_url` | The SAML 2.0 metadata URL of your IdP. Required if `idp.metadata_file` is not set.
## IdP and service provider entity ID
An entity ID is a globally unique name for a SAML entity, either an IdP or a service provider (SP). The IdP entity ID is usually provided by your IdP. The SP entity ID is the name of the configured application or client in your IdP. We recommend adding a new application for OpenSearch Dashboards and using the URL of your OpenSearch Dashboards installation as the SP entity ID.
Name | Description
:--- | :---
`idp.entity_id` | The entity ID of your IdP. Required.
`sp.entity_id` | The entity ID of the service provider. Required.
Occasionally you may find that the clock times between the authentication server and the OpenSearch node are not perfectly synchronized. When this is the case, even by a few seconds, the system that either issues or receives a JSON Web Token (JWT) may try to validate `nbf` (not before) and `exp` (expiration) claims and fail to authenticate the user due to the time disparity.
By default, OpenSearch Security allows for a window of 30 seconds to compensate for possible misalignment between server clock times. To set a custom value for this feature and override the default, you can add the `jwt_clock_skew_tolerance_seconds` setting to the `config.yml`.
The web browser SSO profile exchanges information through HTTP GET or POST. For example, after you log in to your IdP, it sends an HTTP POST back to OpenSearch Dashboards containing the SAML response. You must configure the base URL of your OpenSearch Dashboards installation where the HTTP requests are being sent to.
Name | Description
:--- | :---
`kibana_url` | The OpenSearch Dashboards base URL. Required.
## Username and Role attributes
Subjects (for example, user names) are usually stored in the `NameID` element of a SAML response:
```
<saml2:Subject>
<saml2:NameID>admin</saml2:NameID>
...
</saml2:Subject>
```
If your IdP is compliant with the SAML 2.0 specification, you do not need to set anything special. If your IdP uses a different element name, you can also specify its name explicitly.
Role attributes are optional. However, most IdPs can be configured to add roles in the SAML assertions as well. If present, you can use these roles in your [role mappings]({{site.url}}{{site.baseurl}}/security/access-control/index/#concepts):
`sp.signature_private_key` | The private key used to sign the requests or to decode encrypted assertions. Optional. Cannot be used when `private_key_filepath` is set.
`sp.signature_private_key_password` | The password of the private key, if any.
`sp.signature_private_key_filepath` | Path to the private key. The file must be placed under the OpenSearch `config` directory, and the path must be specified relative to that same directory.
`sp.signature_algorithm` | The algorithm used to sign the requests. See the next table for possible values.
Usually, IdPs provide information about their individual logout URL in their SAML 2.0 metadata. If this is the case, the Security plugin uses them to render the correct logout link in OpenSearch Dashboards. If your IdP does not support an explicit logout, you can force a re-login when the user visits OpenSearch Dashboards again.
SAML, unlike other protocols, is not meant to be used for exchanging user credentials with each request. The Security plugin trades the SAML response for a lightweight JWT that stores the validated user attributes. This token is signed by an exchange key of your choice. Note that when you change this key, all tokens signed with it become invalid immediately.
`exchange_key` | The key to sign the token. The algorithm is HMACSHA512, therefore we recommend to use 64 characters, for example `9a2h8ajasdfhsdiydfn7dtd6d5ashsd89a2h8ajasdHhsdiyLfn7dtd6d5ashsdI`. Ensure that you enter a value for `exchange_key`, otherwise an error is returned.
If you are loading the IdP metadata from a URL, we recommend that you use SSL/TLS. If you use an external IdP like Okta or Auth0 that uses a trusted certificate, you usually do not need to configure anything. If you host the IdP yourself and use your own root CA, you can customize the TLS settings as follows. These settings are used only for loading SAML metadata over HTTPS.
Name | Description
:--- | :---
`idp.enable_ssl` | Whether to enable the custom TLS configuration. Default is false (JDK settings are used).
`idp.verify_hostnames` | Whether to verify the hostnames of the server's TLS certificate.
Example:
```yml
authc:
saml_auth_domain:
http_enabled: true
transport_enabled: false
order: 1
http_authenticator:
type: saml
challenge: true
config:
idp:
enable_ssl: true
verify_hostnames: true
...
authentication_backend:
type: noop
```
### Certificate validation
Configure the root CA used for validating the IdP TLS certificate by setting **one** of the following configuration options:
`idp.pemtrustedcas_filepath` | Path to the PEM file containing the root CAs of your IdP. The files must be placed under the OpenSearch `config` directory, and you must specify the path relative to that same directory.
`idp.pemtrustedcas_content` | The root CA content of your IdP server. Cannot be used when `pemtrustedcas_filepath` is set.
The Security plugin can use TLS client authentication when fetching the IdP metadata. If enabled, the Security plugin sends a TLS client certificate to the IdP for each metadata request. Use the following keys to configure client authentication.
`idp.enable_ssl_client_auth` | Whether to send a client certificate to the IdP server. Default is false.
`idp.pemcert_filepath` | Path to the PEM file containing the client certificate. The file must be placed under the OpenSearch `config` directory, and the path must be specified relative to the `config` directory.
`idp.pemcert_content` | The content of the client certificate. Cannot be used when `pemcert_filepath` is set.
`idp.pemkey_filepath` | Path to the private key of the client certificate. The file must be placed under the OpenSearch `config` directory, and the path must be specified relative to the `config` directory.
`idp.pemkey_content` | The content of the private key of your certificate. Cannot be used when `pemkey_filepath` is set.
`idp.pemkey_password` | The password of your private key, if any.
### Enabled ciphers and protocols
You can limit the allowed ciphers and TLS protocols for the IdP connection. For example, you can only enable strong ciphers and limit the TLS versions to the most recent ones.
Name | Description
:--- | :---
`idp.enabled_ssl_ciphers` | Array of enabled TLS ciphers. Only the Java format is supported.
`idp.enabled_ssl_protocols` | Array of enabled TLS protocols. Only the Java format is supported.
## Minimal configuration example
The following example shows the minimal configuration:
Because most of the SAML-specific configuration is done in the Security plugin, just activate SAML in your `opensearch_dashboards.yml` by adding the following:
To include SAML with other authentication types in the Dashboards sign-in window, see [Configuring sign-in options]({{site.url}}{{site.baseurl}}/security/configuration/multi-auth/).
To improve session management---especially for users who have multiple roles assigned to them---Dashboards provides an option to split cookie payloads into multiple cookies and then recombine the payloads when receiving them. This can help prevent larger SAML assertions from exceeding size limits for each cookie. The two settings in the following example allow you to set a prefix name for additional cookies and specify the number of them. They are added to the `opensearch_dashboards.yml` file. The default number of additional cookies is three:
Note that reducing the number of additional cookies can cause some of the cookies that were in use before the change to stop working. We recommend establishing a fixed number of additional cookies and not changing the configuration after that.
If the ID token from the IdP is especially large, OpenSearch may throw a server log authentication error indicating that the HTTP header is too large. In this case, you can increase the value for the `http.max_header_size` setting in the `opensearch.yml` file.
