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This page describes SAML for Groups. For instance-wide SAML on self-managed GitLab instances, see [SAML OmniAuth Provider](../../../integration/saml.md).
SAML on GitLab.com allows users to sign in through their SAML identity provider. If the user is not already a member, the sign-in process automatically adds the user to the appropriate group.
If you follow our guidance to automate user provisioning using [SCIM](scim_setup.md) or [group-managed accounts](group_managed_accounts.md), you do not need to create such accounts manually.
1. Configure your SAML server using the **Assertion consumer service URL**, **Identifier**, and **GitLab single sign-on URL**. Alternatively GitLab provides [metadata XML configuration](#metadata-configuration). See [specific identity provider documentation](#providers) for more details.
GitLab.com uses the SAML NameID to identify users. The NameID element:
- Is a required field in the SAML response.
- Must be unique to each user.
- Must be a persistent value that will never change, such as a randomly generated unique user ID.
- Is case sensitive. The NameID must match exactly on subsequent login attempts, so should not rely on user input that could change between upper and lower case.
- Should not be an email address or username. We strongly recommend against these as it is hard to guarantee they will never change, for example when a person's name changes. Email addresses are also case-insensitive, which can result in users being unable to sign in.
Once users have signed into GitLab using the SSO SAML setup, changing the `NameID` will break the configuration and potentially lock users out of the GitLab group.
#### NameID Format
We recommend setting the NameID format to `Persistent` unless using a field (such as email) that requires a different format.
Please note that the certificate [fingerprint algorithm](#additional-providers-and-setup-options) must be in SHA1. When configuring the identity provider, use a secure signature algorithm.
With this option enabled, users must go through your group's GitLab single sign-on URL. They may also be added via SCIM, if configured. Users cannot be added manually, and may only access project/group resources via the UI by signing in through the SSO URL.
However, users will not be prompted to sign in through SSO on each visit. GitLab will check whether a user has authenticated through SSO, and will only prompt the user to sign in via SSO if the session has expired.
When [configuring your identify provider](#configuring-your-identity-provider), please consider the notes below for specific providers to help avoid common issues and as a guide for terminology used.
The SAML standard means that a wide range of identity providers will work with GitLab. Unfortunately we have not verified connections with all SAML providers.
For more information, see our [discussion on providers](#providers).
| SAML Profile | Web browser SSO profile | GitLab uses SAML to sign users in via their browser. We don't make requests direct to the Identity Provider. |
| SAML Request Binding | HTTP Redirect | GitLab (the service provider) redirects users to your Identity Provider with a base64 encoded `SAMLRequest` HTTP parameter. |
| SAML Response Binding | HTTP POST | Your Identity Provider responds to users with an HTTP form including the `SAMLResponse`, which a user's browser submits back to GitLab. |
| Sign SAML Response | Yes | We require this to prevent tampering. |
| Fingerprint Algorithm | SHA-1 | We need a SHA-1 hash of the certificate used to sign the SAML Response. |
| Signature Algorithm | SHA-1/SHA-256/SHA-384/SHA-512 | Also known as the Digest Method, this can be specified in the SAML response. It determines how a response is signed. |
| Encrypt SAML Assertion | No | TLS is used between your Identity Provider, the user's browser, and GitLab. |
| Sign SAML Assertion | Optional | We don't require Assertions to be signed. We validate their integrity by requiring the whole response to be signed. |
| Check SAML Request Signature | No | GitLab does not sign SAML requests, but does check the signature on the SAML response. |
| Default RelayState | Optional | The URL users should end up on after signing in via a button on your Identity Provider. |
| NameID Format | `Persistent` | See [details above](#nameid-format). |
| Additional URLs | | You may need to use the `Identifier` or `Assertion consumer service URL` in other fields on some providers. |
If the information you need isn't listed above you may wish to check our [troubleshooting docs below](#i-need-additional-information-to-configure-my-identity-provider).
Once Group SSO is configured and enabled, users can access the GitLab.com group through the identity provider's dashboard. If [SCIM](scim_setup.md) is configured, please see the [user access and linking setup section on the SCIM page](scim_setup.md#user-access-and-linking-setup).
When a user tries to sign in with Group SSO, they will need an account that's configured with one of the following:
1. Locate and visit the **GitLab single sign-on URL** for the group you are signing in to. A group Admin can find this on the group's **Settings > SAML SSO** page. If the sign-in URL is configured, users can connect to the GitLab app from the Identity Provider.
On subsequent visits, you should be able to go [sign in to GitLab.com with SAML](#signing-in-to-gitlabcom-with-saml) or by visiting links directly. If the **enforce SSO** option is turned on, you will be redirected to sign in through the identity provider.
Starting from [GitLab 13.3](https://gitlab.com/gitlab-org/gitlab/-/issues/214523), group owners can set a 'Default membership role' other than 'Guest'. To do so, [configure the SAML SSO for the group](#configuring-gitlab). That role becomes the starting access level of all users added to the group.
Existing members with appropriate privileges can promote or demote users, as needed.
| Service Provider | SAML considers GitLab to be a service provider. |
| Assertion | A piece of information about a user's identity, such as their name or role. Also know as claims or attributes. |
| SSO | Single Sign On. |
| Assertion consumer service URL | The callback on GitLab where users will be redirected after successfully authenticating with the identity provider. |
| Issuer | How GitLab identifies itself to the identity provider. Also known as a "Relying party trust identifier". |
| Certificate fingerprint | Used to confirm that communications over SAML are secure by checking that the server is signing communications with the correct certificate. Also known as a certificate thumbprint. |
## Passwords for users created via SAML SSO for Groups
The [Generated passwords for users created through integrated authentication](../../../security/passwords_for_integrated_authentication_methods.md) guide provides an overview of how GitLab generates and sets passwords for users created via SAML SSO for Groups.
- The [NameID](#nameid), which we use to identify which user is signing in. If the user has previously signed in, this [must match the value we have stored](#verifying-nameid).
- The presence of a `X509Certificate`, which we require to verify the response signature.
- The `SubjectConfirmation` and `Conditions`, which can cause errors if misconfigured.
For convenience, we've included some [example resources](../../../administration/troubleshooting/group_saml_scim.md) used by our Support Team. While they may help you verify the SAML app configuration, they are not guaranteed to reflect the current state of third-party products.
In troubleshooting the Group SAML setup, any authenticated user can use the API to verify the NameID GitLab already has linked to the user by visiting [https://gitlab.com/api/v4/user](https://gitlab.com/api/v4/user) and checking the `extern_uid` under identities.
Similarly, group members of a role with the appropriate permissions can make use of the [members API](../../../api/members.md) to view group SAML identity information for members of the group.
This can then be compared to the [NameID](#nameid) being sent by the Identity Provider by decoding the message with a [SAML debugging tool](#saml-debugging-tools). We require that these match in order to identify users.
If a user is trying to sign in for the first time and the GitLab single sign-on URL has not [been configured](#configuring-your-identity-provider), they may see a 404.
As outlined in the [user access section](#linking-saml-to-your-existing-gitlabcom-account), a group Owner will need to provide the URL to users.
### Message: "SAML authentication failed: Extern uid has already been taken"
This error suggests you are signed in as a GitLab user but have already linked your SAML identity to a different GitLab user. Sign out and then try to sign in again using the SSO SAML link, which should log you into GitLab with the linked user account.
If you do not wish to use that GitLab user with the SAML login, you can [unlink the GitLab account from the group's SAML](#unlinking-accounts).
### Message: "SAML authentication failed: User has already been taken"
| You've tried to link multiple SAML identities to the same user, for a given Identity Provider. | Change the identity that you sign in with. To do so, [unlink the previous SAML identity](#unlinking-accounts) from this GitLab account before attempting to sign in again. |
| When a user account with the email address already exists in GitLab, but the user does not have the SAML identity tied to their account. | The user will need to [link their account](#user-access-and-management). |
Getting both of these errors at the same time suggests the NameID capitalization provided by the Identity Provider didn't exactly match the previous value for that user.
This can be prevented by configuring the [NameID](#nameid) to return a consistent value. Fixing this for an individual user involves [unlinking SAML in the GitLab account](#unlinking-accounts), although this will cause group membership and to-dos to be lost.
### Message: "Request to link SAML account must be authorized"
Ensure that the user who is trying to link their GitLab account has been added as a user within the identity provider's SAML app.
### Stuck in a login "loop"
Ensure that the **GitLab single sign-on URL** has been configured as "Login URL" (or similarly named field) in the identity provider's SAML app.
Alternatively, when users need to [link SAML to their existing GitLab.com account](#linking-saml-to-your-existing-gitlabcom-account), provide the **GitLab single sign-on URL** and instruct users not to use the SAML app on first sign in.
| As mentioned in the [NameID](#nameid) section, if the NameID changes for any user, the user can be locked out. This is a common problem when an email address is used as the identifier. | Follow the steps outlined in the ["SAML authentication failed: User has already been taken"](#message-saml-authentication-failed-user-has-already-been-taken) section. |
### I need additional information to configure my identity provider
Many SAML terms can vary between providers. It is possible that the information you are looking for is listed under another name.
For more information, start with your Identity Provider's documentation. Look for their options and examples to see how they configure SAML. This can provide hints on what you'll need to configure GitLab to work with these providers.
It can also help to look at our [more detailed docs for self-managed GitLab](../../../integration/saml.md).
SAML configuration for GitLab.com is mostly the same as for self-managed instances.
However, self-managed GitLab instances use a configuration file that supports more options as described in the external [OmniAuth SAML documentation](https://github.com/omniauth/omniauth-saml/).
Internally that uses the [`ruby-saml` library](https://github.com/onelogin/ruby-saml), so we sometimes check there to verify low level details of less commonly used options.
It can also help to compare the XML response from your provider with our [example XML used for internal testing](https://gitlab.com/gitlab-org/gitlab/blob/master/ee/spec/fixtures/saml/response.xml).
