Ubuntu – Setting Default Permissions

permissions

I've read a lot of solutions for something like this, but nothing seems to work quite right for me. I have a shared development box used for a few projects that require such a thing and I'd like to configure it so that files created by users in the /opt/dev directory:

  • Are owned by <username>:developers
  • Have permissions set to 774 (files)
  • Have permissions set to 775 (directories)

All developer users have their primary group set to developers so the first requirement has been pretty solid. What's a lot less solid is the actual permissions. They just aren't being set consistently the way we need them to get set and I haven't found the right solution.

I do have the sticky bit set (g+s) based on something else I read at some point, but that wouldn't seem to be particularly useful since all users are in the same primary group.

I also have the default umask set to 002 in /etc/login.defs. I thought that would kind of cover it, that doesn't seem to be the case.

I'd really appreciate any advice about how to get everything lined up properly. I feel like I'm constantly in there adjusting a file here and a directory there just so people can do their work.

Best Answer

Ok, for point 1, the solution is quite easy:

chgrp developers /opt/dev

For points 2 and 3, I suppose you'll need ACL. So, the first thing to do is to edit /etc/fstab to give the option acl to the mountpoint of /opt/dev. If /opt/dev is not on a separate partition you'll need to enable ACL for the whole root filesystem.

Then you'll have to follow this answer.

chmod g+s /opt/dev

should be equivalent to chgrp developers /opt/dev (and doesn't set the sticky bit, s sets the suid bit).

Then proceed with setfacl:

setfacl -d -m g::rwx /opt/dev  //set group to rwx default 
setfacl -d -m o::rx /opt/dev   //set other

to set advanced permission criteria for files and directories. To be honest, I couldn't find a way to set separate file and directory permissions, but I'm pretty sure it's doable. You can try this tutorial to have more information about the topic.

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