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# Shibboleth OmniAuth Provider
This documentation is for enabling shibboleth with omnibus-gitlab package.
In order to enable Shibboleth support in gitlab we need to use Apache instead of Nginx (It may be possible to use Nginx, however this is difficult to configure using the bundled Nginx provided in the omnibus-gitlab package). Apache uses mod_shib2 module for shibboleth authentication and can pass attributes as headers to omniauth-shibboleth provider.
To enable the Shibboleth OmniAuth provider you must configure Apache shibboleth module.
Installation and configuration of module it self is out of scope of this document.
Check <https://wiki.shibboleth.net/> for more info.
You can find Apache config in gitlab-recipes (<https://gitlab.com/gitlab-org/gitlab-recipes/tree/master/web-server/apache>).
The following changes are needed to enable Shibboleth:
1. Protect omniauth-shibboleth callback URL:
```
<Location /users/auth/shibboleth/callback>
AuthType shibboleth
ShibRequestSetting requireSession 1
ShibUseHeaders On
require valid-user
</Location>
Alias /shibboleth-sp /usr/share/shibboleth
<Location /shibboleth-sp>
Satisfy any
</Location>
<Location /Shibboleth.sso>
SetHandler shib
</Location>
```
1. Exclude shibboleth URLs from rewriting. Add `RewriteCond %{REQUEST_URI} !/Shibboleth.sso` and `RewriteCond %{REQUEST_URI} !/shibboleth-sp`. Config should look like this:
```
# Apache equivalent of Nginx try files
RewriteEngine on
RewriteCond %{DOCUMENT_ROOT}/%{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_URI} !/Shibboleth.sso
RewriteCond %{REQUEST_URI} !/shibboleth-sp
RewriteRule .* http://127.0.0.1:8080%{REQUEST_URI} [P,QSA]
RequestHeader set X_FORWARDED_PROTO 'https'
```
1. Edit `/etc/gitlab/gitlab.rb` configuration file to enable OmniAuth and add
Shibboleth as an OmniAuth provider. User attributes will be sent from the
Apache reverse proxy to GitLab as headers with the names from the Shibboleth
attribute mapping. Therefore the values of the `args` hash
should be in the form of `"HTTP_ATTRIBUTE"`. The keys in the hash are arguments
to the [OmniAuth::Strategies::Shibboleth class](https://github.com/toyokazu/omniauth-shibboleth/blob/master/lib/omniauth/strategies/shibboleth.rb)
and are documented by the [omniauth-shibboleth gem](https://github.com/toyokazu/omniauth-shibboleth)
(take care to note the version of the gem packaged with GitLab). If some of
your users appear to be authenticated by Shibboleth and Apache, but GitLab
rejects their account with a URI that contains "e-mail is invalid" then your
Shibboleth Identity Provider or Attribute Authority may be asserting multiple
e-mail addresses. In this instance, you might consider setting the
`multi_values` argument to `first`.
The file should look like this:
```
external_url 'https://gitlab.example.com'
gitlab_rails['internal_api_url'] = 'https://gitlab.example.com'
# disable Nginx
nginx['enable'] = false
gitlab_rails['omniauth_allow_single_sign_on'] = true
gitlab_rails['omniauth_block_auto_created_users'] = false
gitlab_rails['omniauth_enabled'] = true
gitlab_rails['omniauth_providers'] = [
{
"name" => "'shibboleth"',
"label" => "Text for Login Button",
"args" => {
"shib_session_id_field" => "HTTP_SHIB_SESSION_ID",
"shib_application_id_field" => "HTTP_SHIB_APPLICATION_ID",
"uid_field" => 'HTTP_EPPN',
"name_field" => 'HTTP_CN',
"info_fields" => { "email" => 'HTTP_MAIL'}
}
}
]
```
1. [Reconfigure](../administration/restart_gitlab.md#omnibus-gitlab-reconfigure) or [restart](../administration/restart_gitlab.md#installations-from-source) GitLab for the changes to take effect if you
installed GitLab via Omnibus or from source respectively.
On the sign in page, there should now be a "Sign in with: Shibboleth" icon below the regular sign in form. Click the icon to begin the authentication process. You will be redirected to IdP server (depends on your Shibboleth module configuration). If everything goes well the user will be returned to GitLab and will be signed in.
## Apache 2.4 / GitLab 8.6 update
The order of the first 2 Location directives is important. If they are reversed,
you will not get a shibboleth session!
```
<Location />
Require all granted
ProxyPassReverse http://127.0.0.1:8181
ProxyPassReverse http://YOUR_SERVER_FQDN/
</Location>
<Location /users/auth/shibboleth/callback>
AuthType shibboleth
ShibRequestSetting requireSession 1
ShibUseHeaders On
Require shib-session
</Location>
Alias /shibboleth-sp /usr/share/shibboleth
<Location /shibboleth-sp>
Require all granted
</Location>
<Location /Shibboleth.sso>
SetHandler shib
</Location>
RewriteEngine on
#Don't escape encoded characters in api requests
RewriteCond %{REQUEST_URI} ^/api/v4/.*
RewriteCond %{REQUEST_URI} !/Shibboleth.sso
RewriteCond %{REQUEST_URI} !/shibboleth-sp
RewriteRule .* http://127.0.0.1:8181%{REQUEST_URI} [P,QSA,NE]
#Forward all requests to gitlab-workhorse except existing files
RewriteCond %{DOCUMENT_ROOT}/%{REQUEST_FILENAME} !-f [OR]
RewriteCond %{REQUEST_URI} ^/uploads/.*
RewriteCond %{REQUEST_URI} !/Shibboleth.sso
RewriteCond %{REQUEST_URI} !/shibboleth-sp
RewriteRule .* http://127.0.0.1:8181%{REQUEST_URI} [P,QSA]
RequestHeader set X_FORWARDED_PROTO 'https'
RequestHeader set X-Forwarded-Ssl on
```
|
