docs/content/admin/authentication/authenticating-users-for-your-github-enterprise-server-instance/using-saml.md

title, redirect_from, intro, versions, type, topics

title	redirect_from	intro	versions	type	topics
Using SAML	/enterprise/admin/articles/configuring-saml-authentication/ /enterprise/admin/articles/about-saml-authentication/ /enterprise/admin/user-management/using-saml /enterprise/admin/authentication/using-saml /admin/authentication/using-saml	SAML is an XML-based standard for authentication and authorization. {% data variables.product.prodname_ghe_server %} can act as a service provider (SP) with your internal SAML identity provider (IdP).	ghes *	how_to	Accounts Authentication Enterprise Identity SSO

{% data reusables.enterprise_user_management.built-in-authentication %}

Supported SAML services

{% data reusables.saml.saml-supported-idps %}

{% data reusables.saml.saml-single-logout-not-supported %}

Username considerations with SAML

Each {% data variables.product.prodname_ghe_server %} username is determined by one of the following assertions in the SAML response, ordered by priority:

• The custom username attribute, if defined and present
• An http://schemas.xmlsoap.org/ws/2005/05/identity/claims/name assertion, if present
• An http://schemas.xmlsoap.org/ws/2005/05/identity/claims/emailaddress assertion, if present
• The NameID element

The NameID element is required even if other attributes are present.

A mapping is created between the NameID and the {% data variables.product.prodname_ghe_server %} username, so the NameID should be persistent, unique, and not subject to change for the lifecycle of the user.

{% note %}

Note: If the NameID for a user does change on the IdP, the user will see an error message when they try to sign in to your {% data variables.product.prodname_ghe_server %} instance. {% ifversion ghes %}To restore the user's access, you'll need to update the user account's NameID mapping. For more information, see "Updating a user's SAML NameID."{% else %} For more information, see "Error: 'Another user already owns the account'."{% endif %}

{% endnote %}

{% data reusables.enterprise_management_console.username_normalization %}

{% data reusables.enterprise_management_console.username_normalization_sample %}

{% data reusables.enterprise_user_management.two_factor_auth_header %} {% data reusables.enterprise_user_management.external_auth_disables_2fa %}

SAML metadata

Your {% data variables.product.prodname_ghe_server %} instance's service provider metadata is available at http(s)://[hostname]/saml/metadata.

To configure your identity provider manually, the Assertion Consumer Service (ACS) URL is http(s)://[hostname]/saml/consume. It uses the urn:oasis:names:tc:SAML:2.0:bindings:HTTP-POST binding.

SAML attributes

These attributes are available. You can change the attribute names in the [management console](/enterprise/{{ currentVersion }}/admin/guides/installation/accessing-the-management-console/), with the exception of the administrator attribute.

Default attribute name	Type	Description
NameID	Required	A persistent user identifier. Any persistent name identifier format may be used. The NameID element will be used for a {% data variables.product.prodname_ghe_server %} username unless one of the alternative assertions is provided.
administrator	Optional	When the value is 'true', the user will automatically be promoted as an administrator. Any other value or a non-existent value will demote the user to a normal user account.
username	Optional	The {% data variables.product.prodname_ghe_server %} username.
full_name	Optional	The name of the user displayed on their profile page. Users may change their names after provisioning.
emails	Optional	The email addresses for the user. More than one can be specified.
public_keys	Optional	The public SSH keys for the user. More than one can be specified.
gpg_keys	Optional	The GPG keys for the user. More than one can be specified.

Configuring SAML settings

{% data reusables.enterprise_site_admin_settings.access-settings %} {% data reusables.enterprise_site_admin_settings.management-console %} {% data reusables.enterprise_management_console.authentication %} 3. Select SAML. 4. {% data reusables.enterprise_user_management.built-in-authentication-option %} 5. Optionally, to enable unsolicited response SSO, select IdP initiated SSO. By default, {% data variables.product.prodname_ghe_server %} will reply to an unsolicited Identity Provider (IdP) initiated request with an AuthnRequest back to the IdP.

{% tip %}

Note: We recommend keeping this value unselected. You should enable this feature only in the rare instance that your SAML implementation does not support service provider initiated SSO, and when advised by {% data variables.contact.enterprise_support %}.

{% endtip %}

5. Select Disable administrator demotion/promotion if you do not want your SAML provider to determine administrator rights for users on {% data variables.product.product_location %}.
6. In the Single sign-on URL field, type the HTTP or HTTPS endpoint on your IdP for single sign-on requests. This value is provided by your IdP configuration. If the host is only available from your internal network, you may need to [configure {% data variables.product.product_location %} to use internal nameservers](/enterprise/{{ currentVersion }}/admin/guides/installation/configuring-dns-nameservers/).
7. Optionally, in the Issuer field, type your SAML issuer's name. This verifies the authenticity of messages sent to {% data variables.product.product_location %}.
8. In the Signature Method and Digest Method drop-down menus, choose the hashing algorithm used by your SAML issuer to verify the integrity of the requests from {% data variables.product.product_location %}. Specify the format with the Name Identifier Format drop-down menu.
9. Under Verification certificate, click Choose File and choose a certificate to validate SAML responses from the IdP.
10. Modify the SAML attribute names to match your IdP if needed, or accept the default names.

{% ifversion ghes %}

Updating a user's SAML NameID

{% data reusables.enterprise_site_admin_settings.access-settings %} 2. In the left sidebar, click All users. 3. In the list of users, click the username you'd like to update the NameID mapping for. {% data reusables.enterprise_site_admin_settings.security-tab %} 5. To the right of "Update SAML NameID", click Edit . 6. In the "NameID" field, type the new NameID for the user. 7. Click Update NameID.

{% endif %}

Revoking access to {% data variables.product.product_location %}

If you remove a user from your identity provider, you must also manually suspend them. Otherwise, they'll continue to be able to authenticate using access tokens or SSH keys. For more information, see "Suspending and unsuspending users".

Response message requirements

The response message must fulfill the following requirements:

• The <Destination> element must be provided on the root response document and match the ACS URL only when the root response document is signed. If the assertion is signed, it will be ignored.
• The <Audience> element must always be provided as part of the <AudienceRestriction> element. It must match the EntityId for {% data variables.product.prodname_ghe_server %}. This is the URL to the {% data variables.product.prodname_ghe_server %} instance, such as https://ghe.corp.example.com.
• Each assertion in the response must be protected by a digital signature. This can be accomplished by signing each individual <Assertion> element or by signing the <Response> element.
• A <NameID> element must be provided as part of the <Subject> element. Any persistent name identifier format may be used.
• The Recipient attribute must be present and set to the ACS URL. For example:

<samlp:Response ...>
  <saml:Assertion ...>
    <saml:Subject>
      <saml:NameID ...>...</saml:NameID>
      <saml:SubjectConfirmation ...>
        <saml:SubjectConfirmationData Recipient="https://ghe.corp.example.com/saml/consume" .../>
      </saml:SubjectConfirmation>
    </saml:Subject>
    <saml:AttributeStatement>
      <saml:Attribute FriendlyName="USERNAME-ATTRIBUTE" ...>
        <saml:AttributeValue>monalisa</saml:AttributeValue>
      </saml:Attribute>
    </saml:AttributeStatement>
  </saml:Assertion>
</samlp:Response>

Troubleshooting SAML authentication

{% data variables.product.prodname_ghe_server %} logs error messages for failed SAML authentication in the authentication log at /var/log/github/auth.log. For more information about SAML response requirements, see "Response message requirements."

Error: "Another user already owns the account"

When a user signs in to {% data variables.product.prodname_ghe_server %} for the first time with SAML authentication, {% data variables.product.prodname_ghe_server %} creates a user account on the instance and maps the SAML NameID to the account.

When the user signs in again, {% data variables.product.prodname_ghe_server %} compares the account's NameID mapping to the IdP's response. If the NameID in the IdP's response no longer matches the NameID that {% data variables.product.prodname_ghe_server %} expects for the user, the sign-in will fail. The user will see the following message.

Another user already owns the account. Please have your administrator check the authentication log.

The message typically indicates that the person's username or email address has changed on the IdP. {% ifversion ghes %}Ensure that the NameID mapping for the user account on {% data variables.product.prodname_ghe_server %} matches the user's NameID on your IdP. For more information, see "Updating a user's SAML NameID."{% else %}For help updating the NameID mapping, contact {% data variables.contact.contact_ent_support %}.{% endif %}

Error: Recipient in SAML response was blank or not valid

If the Recipient does not match the ACS URL for your {% data variables.product.prodname_ghe_server %} instance, one of the following two error messages will appear in the authentication log when a user attempts to authenticate.

Recipient in the SAML response must not be blank.

Recipient in the SAML response was not valid.

Ensure that you set the value for Recipient on your IdP to the full ACS URL for your {% data variables.product.prodname_ghe_server %} instance. For example, https://ghe.corp.example.com/saml/consume.

Error: "SAML Response is not signed or has been modified"

If your IdP does not sign the SAML response, or the signature does not match the contents, the following error message will appear in the authentication log.

SAML Response is not signed or has been modified.

Ensure that you configure signed assertions for the {% data variables.product.prodname_ghe_server %} application on your IdP.

Error: "Audience is invalid" or "No assertion found"

If the IdP's response has a missing or incorrect value for Audience, the following error message will appear in the authentication log.

Audience is invalid. Audience attribute does not match https://<em>YOUR-INSTANCE-URL</em>

Ensure that you set the value for Audience on your IdP to the EntityId for your {% data variables.product.prodname_ghe_server %} instance, which is the full URL to your {% data variables.product.prodname_ghe_server %} instance. For example, https://ghe.corp.example.com.