Commit e7b3aa9e authored by Evan Read's avatar Evan Read

Merge branch 'jej/document-group-saml-sso-troubleshooting' into 'master'

Add Group SAML troubleshooting documentation

See merge request gitlab-org/gitlab!17998
parents a85fe355 e9c26de9
......@@ -153,14 +153,41 @@ For example, to unlink the `MyOrg` account, the following **Disconnect** button
| 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. |
<!-- ## Troubleshooting
## Troubleshooting
Include any troubleshooting steps that you can foresee. If you know beforehand what issues
one might have when setting this up, or when something is changed, or on upgrading, it's
important to describe those, too. Think of things that may go wrong and include them here.
This is important to minimize requests for support, and to avoid doc comments with
questions that you know someone might ask.
### SAML debugging tools
Each scenario can be a third-level heading, e.g. `### Getting error message X`.
If you have none to add when creating a doc, leave this section in place
but commented out to help encourage others to add to it in the future. -->
SAML responses are base64 encoded, so we recommend the following browser plugins to decode them on the fly:
- [SAML tracer for Firefox](https://addons.mozilla.org/en-US/firefox/addon/saml-tracer/)
- [Chrome SAML Panel](https://chrome.google.com/webstore/detail/saml-chrome-panel/paijfdbeoenhembfhkhllainmocckace?hl=en)
Specific attention should be paid to:
- 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.
### Verifying NameID
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.
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.
### 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"
The user you are signed in with already has SAML linked to a different identity. This might mean you've attempted to link multiple SAML identities to the same user for a given Identity Provider. This could also be a symptom of the Identity Provider returning an inconsistent [NameID](#nameid).
To change which identity you sign in with, you can [unlink the previous SAML identity](#unlinking-accounts) from this GitLab account.
### Message: "SAML authentication failed: Extern uid has already been taken, User has already been taken"
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 Todos to be lost.
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