File server permission

Question

I am trying to give 2 users rwx access to a new shared directory i have created that will hold some shared documents. The directory is /srv/shared The 2 users are Mason and Bill that will be accessing the files. I would like both users to be able to rwx any newly created files/directories by each other.

I have added Bill to the group Mason with sudo usermod -a -G mason bill I then changed the /srv/shared ownership to Mason and group Mason with sudo chown mason:mason /srv/shared

I then tried creating a directory in /srv/shared logged in as bill with mkdir /srv/shared/test but got access denied. I tried giving the directory chmod 755 permissions but that still gave Bill access denied when creating files. When i gave chmod permissions 777 Bill could then create directories and files without an issue.

Just trying to work out what I have done wrong for this to only work with 777 permissions which is not really what i want to allow?

Answer 1

Add the users mason and bill to a new group, lets call them mbshare. Then change the permissions and group on the share point to match the new group. Finally add the users to the group.

// create a new group
sudo groupadd mbshare
// change the permissions on the sharepoint
sudo chgrp -R mbshare /path/to/share
sudo chmod -R 2775 /path/to/share
// make the users part of the share group
sudo usermod -aG mbshare mason
sudo usermod -aG mbshare bill

Now mason and bill can create and edit files in /path/to/share.

The 2 in the 2775 permission flag means: (setGID bit) new files will have the same group as the directory and subdirectories inherit the same as parent.

If you only want mason and bill to see the files within the share, use 2770 instead of 2775.

The advantages of creating a custom group are significant.

• It is easy to add or remove a new user to the group.
• You can quickly see who has access to the group.
• You can remove any user without the need to change any permissions.
• Keeps things very neat and tidy :]

Edit: Corrected a few "from memory" errors.

Answer 2

It should be 775. Since both of them belong to same group. The group should have rwx right. The first 7 for the owner and second 7 for the group.