To me it seems like media upload always use access permission for group "@ALL". It seems like auth_quickaclcheck() fails to identify the user correctly because $_SERVER['REMOTE_USER'] is empty in the media upload window.
This was verified by adding "echo $_SERVER['REMOTE_USER'];" in the auth_aclcheck() function in auth.php. This will correctly print the logged in user name at the top on other pages, but not the media upload window.
This was with the 2006-11-06 dokuwiki version and using plain authentication together with Mozilla Firefox 18.104.22.168.
I can not reproduce this. $_SERVER['REMOTE_USER'] is set correctly in the media windows and ACLs are checked correctly.
Ok, I tested it again on my dokuwiki server and the problem still existed. So I started to fiddle around with a copy of the wiki that I planned to to upload for you to test.
However, while doing this the problem mysteriously disappeared. I even restored a backup of the wiki and the problem was still gone.
The only thing I can think of is that I changed my httpd-configuration while creating the test-case. I use an alias which I may have changed and corrected in the process:
Alias /dokuwiki /var/www/html/wiki/
However, there is still a problem with my renamed install folder. It looks like when uploading media it will always use the "dokuwiki" folder and not my "wiki" folder in the URL. Like "https://a.b.c/wiki/lib/exe/mediamanager.php?ns=cube". Therefore I think it may have been something wrong with my alias of the dokuwiki to the wiki folder However, I cannot reproduce the problem :(
So in short. I cannot reproduce the original problem. But to me it seems like the media upload window will always use "dokuwiki" in the path regardless of my custom install folder. Autodetection does not work. (I've also tried to configure dokuwiki to use "/wiki/" as path but that failed. The same goes for .htaccess rewrite path.)
And now that problem went away as well. After editing "html.php" to try to pinpoint the problem it simply started to work and things started to link using "wiki" instead "dokuwiki" correctly. And I cannot get back the old behavior.
I think I'm going mad...
You can close this issue and ignore my ramblings. Sorry for the inconvenience...