Redirect_uri changes between authorize and token

How to Use GitLab
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redirect_uri changes between authorize and token

I have an issue while trying to use gitlab oauth to mattermost (installed with the omnibus package):

  • I created the application by folllowing this link: GitLab Single Sign-On — Mattermost documentation. I use mattermost and gitlab from the omnibus package. I setup mattermost['gitlab_id'] and mattermost['gitlab_secret'] correctly, mattermost['gitlab_auth_endpoint'], mattermost['gitlab_token_endpoint'] and mattermost['gitlab_user_api_endpoint'] too. Each time I try to connect with gitlab oauth, mattermost return a html page with: “Erreur \n Erreur lors de la récupération du jeton” (Error \n Error when retrieving the token in english)
  • when checking production.log , I saw:
Started GET "/oauth/authorize?response_type=code&client_id=<client_id>&redirect_uri=https%3A%2F%2F<my_domain_name>%2Fsignup%2Fgitlab%2Fcomplete&state=<state>" for <my_ipv4> at <datetime>
Processing by 0auth::AuthorizationsController#new as HTML
 Parameters: {"response_type" => "code", "client_id" => "<client_id>", "redirect_uri" => "https://<my_domain_name>/signup/gitlab/complete", "state" => "<state>"}
Completed 200 OK in 60 ms (Views: 9.2ms | ActiveRecord: 10.5ms | Elasticsearch: 0.0ms | Allocations: 16159)
Started POST "/oauth/token" for <my_ipv6> at <datetime>
Processing by 0auth::TokensController#create as JSON
  Parameters: {"client_id" => "<client_id>", "client_secret" => "[FILTERED]", "code" => "[FILTERED]", "grant_type" => "authorization_code", "redirect_uri" => "http://<my_domain_name>/signup/gitlab/complete"}
Completed 400 Bad Request in 88ms (Views: 0.2ms | ActiveRecord: 0.0ms | Elasticsearch: 0.0ms | Allocations: 16531)
  • We can see that the https request became an http one for some reason I don’t understand.
  • Version: gitlab-ce 15.3.2 (self-hosted)
  • I use apache so I checked this, and added the header. I checked my gitlab.rb, production.log and mattermost.log

To be sure, here my apache configuration for gitlab:

<VirtualHost *:80>
	ServerName <my_domain_name_for_gitlab>
	ServerAdmin <my_email>

	RewriteEngine On
	RewriteCond %{HTTPS} !=on
	RewriteRule .* https://%{SERVER_NAME}%{REQUEST_URI} [NE,R,L]

	ErrorLog ${APACHE_LOG_DIR}/<my_domain_name_for_gitlab>_error.log
	CustomLog ${APACHE_LOG_DIR}/<my_domain_name_for_gitlab>.log combined
</VirtualHost>

<VirtualHost *:443>
	ServerName <my_domain_name_for_gitlab>
	ServerAdmin <my_email>

	ProxyPreserveHost On

	AllowEncodedSlashes NoDecode

	<Location />
		Require all granted

		ProxyPassReverse http://127.0.0.1:8181
		ProxyPassReverse http://<my_domain_name_for_gitlab>
	</Location>

	DocumentRoot /opt/gitlab/embedded/service/gitlab-rails/public

	RewriteEngine on
	RewriteCond %{REQUEST_URI} ^/api/v\d+/.* [OR]
	RewriteCond %{REQUEST_URI} .*-/branches/.* [OR]
	RewriteCond %{REQUEST_URI} .*-/refs/.*/logs_tree/.* [OR]
	RewriteCond %{REQUEST_URI} .*-/tree/.*

	RewriteRule .* http://127.0.0.1:8181%{REQUEST_URI} [P,QSA,NE]

	RewriteCond %{DOCUMENT_ROOT}/%{REQUEST_FILENAME} !-f [OR]
	RewriteCond %{REQUEST_URI} ^/uploads/.*
	RewriteRule .* http://127.0.0.1:8181%{REQUEST_URI} [P,QSA]
	
	RequestHeader set X_FORWARDED_PROTO 'https'
	RequestHeader set X-Forwarded-Ssl on

	SSLEngine on
	SSLProtocol all -SSLv2
	SSLHonorCipherOrder on
	SSLCipherSuite "ECDH+AESGM:DH+AESGCM:ECDH+AES256:DH+AES256:ECDH+AES128:DH+AES:ECDH+3DES:DH+3DES:RSA+AESGCM:RSA+AES:RSA:3DES:!aNULL:!MD5:!DSS"
	Header add Strict-Transport-Security: "max-age=15768000; IncludeSubdomains"
	SSLCompression Off

	SSLCertificateFile /etc/letsencrypt/live/<my_domain_name_for_gitlab>/fullchain.pem
	SSLCertificateKeyFile /etc/letsencrypt/live/<my_domain_name_for_gitlab>/privkey.pem
	SSLCACertificateFile /etc/letsencrypt/live/<my_domain_name_for_gitlab>/fullchain.pem

	ErrorDocument 404 /404.html
	ErrorDocument 422 /422.html
	ErrorDocument 500 /500.html
	ErrorDocument 502 /502.html
	ErrorDocument 503 /503.html

	ErrorLog ${APACHE_LOG_DIR}/<my_domain_name_for_gitlab>_error.log
	CustomLog ${APACHE_LOG_DIR}/<my_domain_name_for_gitlab>.log combined
</VirtualHost>

and my configuration for mattermost:

<VirtualHost *:80>
	ServerName <my_domain_name>
	ServerAdmin <my_email>
	ServerSignature Off

	RewriteEngine On
	RewriteCond %{HTTPS} !=on
	RewriteRule .* https://%{SERVER_NAME}%{REQUEST_URI} [NE,R,L]

	ErrorLog ${APACHE_LOG_DIR}/<my_domain_name>_error.log
	CustomLog ${APACHE_LOG_DIR}/<my_domain_name>.log combined
</VirtualHost>

<VirtualHost *:443>
	ServerName <my_domain_name>
	ServerAdmin <my_email>

	DocumentRoot /var/opt/gitlab/mattermost
	ProxyPreserveHost On

	<Proxy *>
		Order allow,deny
		Allow from all
	</Proxy>

	RewriteEngine On
	RewriteCond %{REQUEST_URI} ^/api/v4/users/websocket [NC,OR]
	RewriteCond %{HTTP:UPGRADE} ^WebSocket$ [NC,OR]
	RewriteCond %{HTTP:CONNECTION} ^Upgrade$ [NC]
	RewriteRule .* ws://127.0.0.1:8065%{REQUEST_URI} [P,QSA,L]
	RewriteCond %{DOCUMENT_ROOT}/%{REQUEST_FILENAME} !-f
	RewriteRule .* http://127.0.0.1:8065%{REQUEST_URI} [P,QSA,L]

	<Location /api/v4/users/websocket>
		Require all granted
		ProxyPass ws://127.0.0.1:8065/api/v4/users/websocket
		ProxyPassReverse ws://127.0.0.1:8065/api/v4/users/websocket
		ProxyPassReverseCookieDomain 127.0.0.1 <my_domain_name>
	</Location>

	<Location />
		Require all granted
		ProxyPass http://127.0.0.1:8065/
		ProxyPassReverse http://127.0.0.1:8065/
		ProxyPassReverseCookieDomain 127.0.0.1 <my_domain_name>
	</Location>
	
	RequestHeader set X_FORWARDED_PROTO 'https'
	RequestHeader set X-Forwarded-Ssl on

	SSLEngine on
	SSLProtocol all -SSLv2
	SSLHonorCipherOrder on
	SSLCipherSuite "ECDH+AESGM:DH+AESGCM:ECDH+AES256:DH+AES256:ECDH+AES128:DH+AES:ECDH+3DES:DH+3DES:RSA+AESGCM:RSA+AES:RSA:3DES:!aNULL:!MD5:!DSS"
	Header add Strict-Transport-Security: "max-age=15768000; IncludeSubdomains"
	SSLCompression Off

	SSLCertificateFile /etc/letsencrypt/live/<my_domain_name>/fullchain.pem
	SSLCertificateKeyFile /etc/letsencrypt/live/<my_domain_name>/privkey.pem
	SSLCACertificateFile /etc/letsencrypt/live/<my_domain_name>/fullchain.pem

	ErrorLog ${APACHE_LOG_DIR}/<my_domain_name>_error.log
	CustomLog ${APACHE_LOG_DIR}/<my_domain_name>.log combined
</VirtualHost>

It’s my first issue so I’m sorry if I forgot something, don’t hesitate to ask me, thank you.