SSH Authentication with OneLogin

This guide will explain how to configure OneLogin to issue SSH credentials to specific groups of users. When used in combination with role based access control (RBAC) it allows SSH administrators to define policies like:

• Only members of "DBA" group can SSH into machines running PostgreSQL.
• Developers must never SSH into production servers.
• ... and many others.

Prerequisites

• One Login account with admin access and users assigned to at least two groups.
• Teleport role with access to maintaining saml resources. This is available in the default editor role.

tsh login --proxy=teleport.example.com [email protected]
tctl status
Cluster  teleport.example.com
Version  12.1.1
CA pin   sha256:abdc1245efgh5678abdc1245efgh5678abdc1245efgh5678abdc1245efgh5678

tsh login --proxy=myinstance.teleport.sh [email protected]
tctl status
Cluster  myinstance.teleport.sh
Version  12.1.1
CA pin   sha256:sha-hash-here

Enable default SAML authentication

Configure Teleport to use SAML authentication as the default instead of the local user database.

You can either edit your Teleport configuration file or create a dynamic resource.

auth_service:
  authentication:
    type: saml

Configure Application

Using OneLogin control panel, create a SAML 2.0 Web App in SAML configuration section:

Download Icons

• Square Icon
• Rectangular Icon

Set Audience, Recipient and ACS (Consumer) URL Validator to the same value:

https://teleport.example.com:3080/v1/webapi/saml/acs where teleport.example.com is the public name of the teleport web proxy service:

Teleport needs to assign groups to users. Configure the application with some parameters exposed as SAML attribute statements:

Add users to the application:

Download SAML XML Metadata

Once the application is set up, download SAML Metadata.

Create a SAML Connector

Now, create a SAML connector resource. Write down this template as onelogin-connector.yaml:

kind: saml
version: v2
metadata:
  name: OneLogin
spec:
  acs: https://<cluster-url>/v1/webapi/saml/acs
  # Controls whether IdP-initiated SSO is allowed. If false, all such requests will be rejected with an error.
  allow_idp_initiated: false
  attributes_to_roles:
    - {name: "groups", value: "admin", roles: ["editor"]}
    - {name: "groups", value: "dev", roles: ["access"]}
  display: OneLogin
  entity_descriptor: |
    # Paste in downloaded content from OneLogin Dashboard.
    <md:EntityDescriptor xmlns:md="urn:oasis:names:tc:SAML:2.0:metadata" entityID="http://www.example.com/00000000000000000000">
      <md:IDPSSODescriptor WantAuthnRequestsSigned="false"

Update the acs value with your public cluster URL and paste the SAML metadata that you previously downloaded in entity_descriptor.

Create the connector using tctl tool:

tctl create onelogin-connector.yaml

Create a new Teleport Role

We are going to create a new that'll use external username data from OneLogin to map to a host linux login.

In the below role, Devs are only allowed to login to nodes labelled with access: relaxed Teleport label. Developers can log in as either ubuntu to a username that arrives in their assertions. Developers also do not have any rules needed to obtain admin access to Teleport.

kind: role
version: v5
metadata:
  name: dev
spec:
  options:
    max_session_ttl: "24h"
  allow:
    logins: [ "{{external.username}}", ubuntu ]
    node_labels:
      access: relaxed

Notice: Replace ubuntu with linux login available on your servers!

tctl create dev.yaml

Testing

The Web UI will now contain a new button: "Login with OneLogin". The CLI is the same as before:

tsh --proxy=proxy.example.com login

This command will print the SSO login URL (and will try to open it automatically in a browser).

Troubleshooting

Troubleshooting SSO configuration can be challenging. Usually a Teleport administrator must be able to:

• Ensure that HTTP/TLS certificates are configured properly for both Teleport proxy and the SSO provider.

• Be able to see what SAML/OIDC claims and values are getting exported and passed by the SSO provider to Teleport.
• Be able to see how Teleport maps the received claims to role mappings as defined in the connector.

If something is not working, we recommend to:

• Double-check the host names, tokens and TCP ports in a connector definition.

Using the Web UI

If you get "access denied" or other login errors, the number one place to check is the Audit Log. You can access it in the Activity tab of the Teleport Web UI.

Example of a user being denied because the role clusteradmin wasn't set up:

{
  "code": "T1001W",
  "error": "role clusteradmin is not found",
  "event": "user.login",
  "method": "oidc",
  "success": false,
  "time": "2019-06-15T19:38:07Z",
  "uid": "cd9e45d0-b68c-43c3-87cf-73c4e0ec37e9"
}

Teleport does not show the expected Nodes

When Teleport's Auth Service receives a request to list Teleport Nodes (e.g., to display Nodes in the Web UI or via tsh ls), it only returns the Nodes that the current user is authorized to view.

For each Node in the user's Teleport cluster, the Auth Service applies the following checks in order and, if one check fails, hides the Node from the user:

• None of the user's roles contain a deny rule that matches the Node's labels.
• At least one of the user's roles contains an allow rule that matches the Node's labels.

If you are not seeing Nodes when expected, make sure that your user's roles include the appropriate allow and deny rules as documented in the Teleport Access Controls Reference.

When configuring SSO, ensure that the identity provider is populating each user's traits correctly. For a user to see a Node in Teleport, the result of populating a template variable in a role's allow.logins must match at least one of a user's traits.logins.

In this example a user will have usernames ubuntu, debian and usernames from the SSO trait logins for Nodes that have a env: dev label. If the SSO trait username is bob then the usernames would include ubuntu, debian, and bob.

kind: role
metadata:
  name: example-role
spec:
  allow:
    logins: ['{{external.logins}}', ubuntu, debian]
    node_labels:
      'env': 'dev'
version: v5