How to give to some user permissions only to subfolder

Question

I have root permissions on my server and I want to give permissions to particular groups and users of it. There is a one case, there is directory tree:

  dir1
    ├── subdir1
    ├── subdir2
    ├── subdir3

I have three users (user1, user2, user3) - i want each of them to have permissions only to one directory (user1 - subdir1, user2 - subdir2, user3 - subdir3). User1 should not be able to see whats int subdir2 or subdir3, but he cant see that they exist, same with other users and their dirs.

I give persmissions using getfacl and setfacl commands.

What permissions should these users have to dir1 and subdirs?

Solution

To allow all users see list of files in dir1 set permissions 0755 to this folder

$ chmod dir1 0755

To separate access to subfolders assign owner to each folder:

$ cd dir1

$ chown user1:user1 -R subdir1
$ chown user2:user2 -R subdir2
$ chown user3:user3 -R subdir3

Now make subfolders readable only for theirs owners:

$ chmod user* 0700

Now all users see that folders user* exist, but they can enter only in own folder

Update Sorry, can't format text in comments.

When I have more users than these three, and I want only these three to be able to enter dir1 - what then?

Then you have to assign them one special group and allow this group to read content of dir1.

Create group specialusers

$ groupadd specialusers

Add users in this group

$ usermod -aG specialusers user1
$ usermod -aG specialusers user2
$ usermod -aG specialusers user3

Allow specialusers to read folder

$ chown root:specialusers dir1
$ chmod dir1 0750

Now only users from in group specialusers can see a list of folders under dir1