How to add new Linux user restricted to ssh tunneling with password?

Question

I wanted to create a new user on my linux server so that he can access my postgres database through an ssh tunnel. However, I want him to restrict his access only to the ssh tunnel.

I followed these steps:

1. login on server as root
2. Create a new user with useradd new_user -M -s /bin/true
3. Set a password with passwd new_user
4. make sure that PasswordAuthentication yes is set and uncomment in /etc/ssh/sshd_config
5. Restart ssh with sudo systemctl reload sshd
6. Logout from server and login to server with new user with ssh -p 7822 new_user@my_address.com -N 5433:localhost:5432 (I am using a2hosting as a provider, where I need to use port 7822 for ssh)

However, when I try to login I get the error

Permission denied, please try again.

When I do everything like above but change step 2 into

useradd new_user -m -d /home/new_user

I can successfully login with the new user, however, I then have the possibility to actually access command line, which I try to avoid. What am I doing wrong here?

Answer 1

Match user foo
    ForceCommand echo 'Only TCP port forwarding to PostgreSQL enabled!'
    PermitOpen 127.0.0.1:5432
    PermitUserRC no
    PermitTTY no