Ubuntu – How to create new user with Public key authentication

addusersshuser-managementuseraddusers

I have Ubuntu Server 14.04 LTS. I have Public key authentication enabled by default.

I used the following command to create new user:

sudo useradd -m -c "John T." john -s /bin/bash

The command apparently created user, user's home folder… but obviously user cannot log in, because user does not have a key. What's next? How to create key and attach it to the user?

-c -- User's full name
-m -- Creates user's home directory
-s -- Specify user's login shell

Best Answer

You need to store his public key in ~john/.ssh/authorized_keys as described in manual page for sshd (good place to start). Also you need to make sure the ~john/.ssh/ directory is owned by john and has 0700 permissions and ~john/.ssh/authorized_keys also with permissions 0600.

Then the user should be able to log in.

Related Solutions

Ubuntu – Ubuntu 14.04: New user created from command line has missing features

First notice that it's better to use adduser and not useradd.

Now back to your command:

You should run the command in the following manner:

sudo useradd -m -c "Samwise the Brave" sam  -s /bin/bash

man useradd

  -s, --shell SHELL
           The name of the user's login shell. The default is to leave this
           field blank, which causes the system to select the default login
           shell specified by the SHELL variable in /etc/default/useradd, or
           an empty string by default.

 -m, --create-home
           Create the user's home directory if it does not exist. The files
           and directories contained in the skeleton directory (which can be
           defined with the -k option) will be copied to the home directory.

           By default, if this option is not specified and CREATE_HOME is not
           enabled, no home directories are created.

So you miss to use -s to add your login shell and the -m to create your home.

If you want to add multiple users in the same time, it's better to use the command `newusers`. It'll simplify your task.

man newusers

DESCRIPTION

   The newusers command reads a file of user name and clear-text password
   pairs and uses this information to update a group of existing users or
   to create new users. Each line is in the same format as the standard
   password file (see passwd(5)) with the exceptions explained below:

   pw_name:pw_passwd:pw_uid:pw_gid:pw_gecos:pw_dir:pw_shell

Here some tutorial about newusers command:

Ubuntu – Public key authentication Permission denied (publickey)

When I tried ssh -i ~/.ssh/key_name user@domain there was a response from the server that said Agent admitted failure to sign using the key.. This is apparently due to gnome-keyring interference issue and the fix is discussed in this link.

A temporary fix is to try SSH_AUTH_SOCK=0 ssh user@domain and if with this you can ssh into your server then follow with the fix in the above link.

Best Answer

Related Solutions

Ubuntu – Ubuntu 14.04: New user created from command line has missing features

If you want to add multiple users in the same time, it's better to use the command newusers. It'll simplify your task.

Ubuntu – Public key authentication Permission denied (publickey)

Related Question

If you want to add multiple users in the same time, it's better to use the command `newusers`. It'll simplify your task.