No More Backdoors: Know Who Has Access to What, Right Now
Jun 13
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Teleport Authentication with OneLogin

This guide will explain how to configure OneLogin to issue Teleport 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 connect to PostgreSQL databases.
  • Developers must never SSH into production servers.
  • ... and many others.

Prerequisites

  • A OneLogin 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.
  • To check that you can connect to your Teleport cluster, sign in with tsh login, then verify that you can run tctl commands using your current credentials. tctl is supported on macOS and Linux machines. For example:
    tsh login --proxy=teleport.example.com --user=[email protected]
    tctl status

    Cluster teleport.example.com

    Version 15.3.7

    CA pin sha256:abdc1245efgh5678abdc1245efgh5678abdc1245efgh5678abdc1245efgh5678

    If you can connect to the cluster and run the tctl status command, you can use your current credentials to run subsequent tctl commands from your workstation. If you host your own Teleport cluster, you can also run tctl commands on the computer that hosts the Teleport Auth Service for full permissions.

Step 1/3. Create Teleport application in OneLogin

In the OneLogin control panel's main menu navigate to Applications -> Add App. Using the search box, select "SAML Custom Connector (SP Shibboleth)":

Define the new application:

You can find Teleport icons to upload from the following links:

From the application's Configuration page, set the following values:

Tip

Set teleport.example.com:443 here with your Teleport Proxy Service address and port, or Teleport Enterprise Cloud tenant (e.g. company.teleport.sh:443) to fill out the values below.

  • Login URL:
    • https://teleport.example.com:443/web/login
  • ACS (Consumer) URL, SAML Recipient, ACS (Consumer) URL Validator, & Audience:
    • https://teleport.example.com:443/v1/webapi/saml/acs/onelogin

Teleport needs to assign groups to users. From the Parameters page, configure the application with some parameters exposed as SAML attribute statements:

Important

Make sure to check Include in SAML assertion checkbox.

Add users to the application:

Download SAML XML metadata

Once the application is set up, download SAML Metadata from the More Actions menu:

Step 2/3. Create a SAML connector

Create a SAML connector using tctl. Update ./onelogin_metadata_1234567.xml with the path to the XML metadata file downloaded in the previous step:

tctl sso configure saml --preset onelogin \--entity-descriptor ./onelogin_metadata_1234567.xml \--attributes-to-roles groups,admin,editor \--attributes-to-roles groups,dev,access > onelogin.yaml

This will create onelogin.yaml, describing the connector resource:

kind: saml
version: v2
metadata:
  name: OneLogin
spec:
  acs: https://teleport.example.com/v1/webapi/saml/acs/onelogin
  attributes_to_roles:
  - name: groups
    roles:
    - editor
    value: admin
  - name: groups
    roles:
    - access
    value: dev
  audience: https://teleport.example.com:443/v1/webapi/saml/acs/onelogin
  cert: ""
  display: OneLogin
  entity_descriptor: |
    <md:EntityDescriptor xmlns:md="urn:oasis:names:tc:SAML:2.0:metadata" entityID="http://www.example.com/00000000000000000000">
      <md:IDPSSODescriptor WantAuthnRequestsSigned="false"
  entity_descriptor_url: ""
  issuer: ""
  service_provider_issuer: https://teleport.example.com:443/v1/webapi/saml/acs/onelogin
  sso: ""
version: v2

Test the newly created configuration:

cat onelogin.yaml | tctl sso test

tctl sso test will open the browser and attempt to authenticate with OneLogin. If it succeeds the output will print what SAML attributes are received and mapped to Teleport roles. If the test fails, the output will help you troubleshoot your configuration.

Create the connector using tctl tool:

tctl create -f onelogin.yaml

Enable default SAML authentication

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

Follow the instructions for your Teleport edition:

Use tctl to edit the cluster_auth_preference value:

tctl edit cluster_auth_preference

Set the value of spec.type to saml:

kind: cluster_auth_preference
metadata:
  ...
  name: cluster-auth-preference
spec:
  ...
  type: saml
  ...
version: v2

After you save and exit the editor, tctl will update the resource:

cluster auth preference has been updated

Update /etc/teleport.yaml in the auth_service section and restart the teleport daemon.

auth_service:
  authentication:
    type: saml
Tip

If you need to log in again before configuring your SAML provider, use the flag --auth=local.

Step 3/3. 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 role described below, 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.

# dev.yaml
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 -f dev.yaml

Troubleshooting

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

  • 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.
  • For self-hosted Teleport Enterprise clusters, ensure that HTTP/TLS certificates are configured properly for both the Teleport Proxy Service and the SSO provider.

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. Under the Management area you can access it within the Activity tab in 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

Single sign-on fails with OIDC

When encountering the error message "Failed to verify JWT: oidc: unable to verify JWT signature: no matching keys", it typically indicates a discrepancy between the algorithm used to sign the JWT token and the algorithm(s) supported by the JSON Web Key Set (JWKS). Specifically, the token might be signed with one algorithm, e.g., HS256, while the JWKS only lists keys for a different algorithm. e.g., RS256. This issue predominantly arises when using identity providers that offer extremely low-level functionality.

Here are some things to check:

  • Verify the JWT header specifies the correct signing algorithm. This should match one of the algorithms listed in the keys section of the JWKS endpoint response.
  • Ensure the JWKS endpoint is returning all relevant public keys. Sometimes key rotation can cause valid keys to be omitted.

To resolve the issue, align the JWT algorithm header with a supported algorithm in the JWKS. Rotate keys if necessary. Verify the JWKS only publishes the active public keys. With proper configuration, the signature should validate successfully.

Next steps

In the Teleport role we illustrated in this guide, external traits are replaced with values from the single sign-on provider that the user used to authenticate to Teleport. For full details on how traits work in Teleport roles, see the Teleport Access Controls Reference.