Add Group Permission to Run chmod Command on Group Owned Files

Question

I've been searching for about an hour now and all google ever returns are hits for how to use chmod.

I want to be able to grant users that are part of a unix group permission to run chmod on files that are owned by that same group. Is this possible? Currently I get permission denied.

If I have the following file:

-rw-rwxr--  1 root tunegroup 5100 Nov  5 23:36 index.html

And as a user that's a member of tunegroup I run:

chmod g-x index.html

I get this as the output:

chmod: changing permissions of ‘index.html’: Operation not permitted

Users won't be able to use sudo since they aren't super users, I just want them to have chmod permission on files that they are group owners of and this seems like a logical ability, but I can't find how to add this permission anywhere...

Answer 1

For what I know, only the owner of the file (and root) are allowed to change the permissions bit of a file.

So for doing what you want probably you should resort to write a little program that change the permissions as you want, and use the sudoers mechanism to give access to it to all the users of the group.

The script could be a simple one that checks if the files is of the "tunegroup" one, and if yes, execute the command as root. (It is important to check for all kind of errors here to avoid abuse). Then you can enable normal users (or users of the aforementioned group) to run this script as root.