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# apt install libapache2-mod-auth-openidc
# cat /etc/apache2/sites-available/default-ssl.conf
...
OIDCProviderMetadataURL https://gitlab.bmstu.ru/.well-known/openid-configuration
OIDCClientID 802..........................................................4c8
OIDCClientSecret 991..........................................................5e7
OIDCRedirectURI https://val.bmstu.ru/auth-test
OIDCCryptoPassphrase h...any.....string.....j
<Directory /home/val/auth-test>
Options ExecCGI Indexes FollowSymLinks
AddHandler cgi-script .cgi
DirectoryIndex env.cgi
AuthType openid-connect
Require valid-user
</Directory>
Alias /auth-test "/home/val/auth-test"
...
https://val.bmstu.ru/auth-test/