How to give user permissions on ubuntu server?

If /home is owned by root, which it probably is... you can always revoke read access for "others" on the /home directory itself.

sudo chmod o-r /home

If your concerned about that level of access, you might be better off using some kind of chroot or jail for users. There's pam_chroot and rssh that can be used to restrict users, and I'm sure some more jail options as well.