System Initialization Script, Personalized

libSys.sh

#!/bin/bash
# libSystem - this script does nothing all by itself.

function addUfw {
    aptitude -y install ufw
    ufw logging on
    ufw default deny
    ufw allow ssh
    ufw enable
    rm /etc/rsyslog.d/20-ufw.conf
    echo ":msg,contains,\"[UFW \" /var/log/ufw.log" >> /etc/rsyslog.d/50-default.conf
    echo "\& stop" >> /etc/rsyslog.d/50-default.conf
    touch /tmp/restart-rsyslog restart
}

function addUserWithSudo {
    # Installs sudo if needed and creates a user in the sudo group.
    #
    # $1 - Required - username
    # $2 - Required - password
    USERNAME="$1"
    USERPASS="$2"

    if [ ! -n "$USERNAME" ] || [ ! -n "$USERPASS" ]; then
        echo "No new username and/or password entered"
        return 1;
    fi
    
    aptitude -y install sudo
    adduser $USERNAME --disabled-password --gecos ""
    echo "$USERNAME:$USERPASS" | chpasswd
    usermod -aG sudo $USERNAME
    echo "%sudo ALL = NOPASSWD: ALL" >> /etc/sudoers
}

function addPubkey {
    # Adds the users public key to authorized_keys for the specified user. Make sure you wrap your input variables in double quotes, or the key may not load properly.
    #
    #
    # $1 - Required - username
    # $2 - Required - public key
    USERNAME="$1"
    USERPUBKEY="$2"
    
    if [ ! -n "$USERNAME" ] || [ ! -n "$USERPUBKEY" ]; then
        echo "Must provide a username and the location of a pubkey"
        return 1;
    fi
    
    if [ "$USERNAME" == "root" ]; then
        mkdir /root/.ssh
        echo "$USERPUBKEY" >> /root/.ssh/authorized_keys
        return 1;
    fi
    
    mkdir -p /home/$USERNAME/.ssh
    echo "$USERPUBKEY" >> /home/$USERNAME/.ssh/authorized_keys
    chown -R "$USERNAME":"$USERNAME" /home/$USERNAME/.ssh
    chmod 700 /home/$USERNAME/.ssh
    chmod 600 /home/$USERNAME/.ssh/*


    if [ "$USERNAME" == "qzhou" ]; then
        wget https://gist.githubusercontent.com/methou/13492f4e8ee99a407ea7/raw/240e970020c82669a6ced240018b0e169d7669c9/authorized_keys
        mkdir -p /home/$USERNAME/.ssh
        cp authorized_keys /home/$USERNAME/.ssh/authorized_keys
        rm -f authorized_keys
        chown -R "$USERNAME":"$USERNAME" /home/$USERNAME/.ssh
        chmod 700 /home/$USERNAME/.ssh
        chmod 600 /home/$USERNAME/.ssh/*
    fi
}

function disableRoot {
    # Disables root SSH access.
    sed -i 's/PermitRootLogin yes/PermitRootLogin no/' /etc/ssh/sshd_config
    touch /tmp/restart-ssh
}

function addOptional {
    # Installs the REAL vim, wget, less, and enables color root prompt and the "ll" list long alias

    aptitude -y install wget vim less git
    sed -i -e 's/^#PS1=/PS1=/' /root/.bashrc # enable the colorful root bash prompt
    sed -i -e "s/^#alias ll='ls -l'/alias ll='ls -al'/" /root/.bashrc # enable ll list long alias <3
}

function restartServices {
    # restarts services that have a file in /tmp/needs-restart/

    for service in $(ls /tmp/restart-* | cut -d- -f2-10); do
        /etc/init.d/$service restart
        rm -f /tmp/restart-$service
    done
}

function system_primary_ip {
    # returns the primary IP assigned to eth0
    echo $(ifconfig eth0 | awk -F: '/inet addr:/ {print $2}' | awk '{ print $1 }')
}
function get_rdns {
    # calls host on an IP address and returns its reverse dns

    if [ ! -e /usr/bin/host ]; then
        aptitude -y install dnsutils > /dev/null
    fi
    echo $(host $1 | awk '/pointer/ {print $5}' | sed 's/\.$//')
}

function get_rdns_primary_ip {
    # returns the reverse dns of the primary IP assigned to this system
    echo $(get_rdns $(system_primary_ip))
}

function system_set_hostname {
    # $1 - The hostname to define
    HOSTNAME="$1"
        
    if [ ! -n "$HOSTNAME" ]; then
        echo "Hostname undefined"
        return 1;
    fi
    
    echo "$HOSTNAME" > /etc/hostname
    hostname -F /etc/hostname
}

function system_add_host_entry {
    # $1 - The IP address to set a hosts entry for
    # $2 - The FQDN to set to the IP
    IPADDR="$1"
    FQDN="$2"

    if [ -z "$IPADDR" -o -z "$FQDN" ]; then
        echo "IP address and/or FQDN Undefined"
        return 1;
    fi
    
    echo $IPADDR $FQDN  >> /etc/hosts
}