openELEC.sh

#!/bin/bash
#
# author: Tim "xGhOsTkiLLeRx" Brust
# license: CC BY-NC-SA 4.0
# version: 0.2
# date: 07/10/2014
# description: replace (root) password of squashfs from openELEC
# usage: ./openELEC [password] [device] [hash] [user]
# dependencies: mkpassword (whois), squashfs-tools
#
#
# THIS SCRIPT COMES WITH ZERO WARRANTY!
# I'M NOT RESPONSIBLE FOR ANY POTENTIAL DATA LOSS!
# ALWAYS CREATE BACKUPS!

# Configure colors, if available.
if [ -x /usr/bin/tput ] && tput setaf 1 >& /dev/null
  then
    reset="$(/usr/bin/tput sgr 0)"
    green="$(/usr/bin/tput bold)$(/usr/bin/tput setaf 2)"
    red="$(/usr/bin/tput bold)$(/usr/bin/tput setaf 1)"
    yellow="$(/usr/bin/tput bold)$(/usr/bin/tput setaf 3)"
else
    reset=
    green=
    red=
    yellow=
fi

# Functions
function cleanUp() {
  rm -rf /openelec
}

function message() {
  echo -e $2"$1"$reset
}

function unmount() {
  umount /openelec/original
  umount /openelec/flash
}

# root check
if [ $EUID -ne 0 ]
  then
    message "Please run this script as root" $red
    exit 1
fi

# whois (makepasswd) check
if ! type "mkpasswd" > /dev/null 2>&1
  then
    message "Please install the package $yellow'whois'$red to use mkpasswd" $red
    exit 1
fi

# mksquashfs check
if ! type "mksquashfs" > /dev/null 2>&1
  then
    message "Please install the package $yellow'squashfs-tools'$red to use mksquashfs" $red
    exit 1
fi

# Ask if we are using BerryBoot
read -p $red"Are you using BerryBoot? (y/N) $reset" berryboot
case "$berryboot" in
  No|no|N|n|"")
      berryboot=false
      ;;
      *)
      berryboot=true
      ;;
esac

# Check for password
if [ -z "$1" ]
  then
    message "No arguments given, please feed me input!\n" $yellow
    read -p "Please enter the password you want to use: " passwd
  else
    passwd=$1
fi

# Check for device
if [ -z "$2" ]
  then
    read -p "Please specify the openELEC device (e.g. sdb1): " device
    if [ "$berryboot" = false ]
      then
        filename=SYSTEM
    fi
  else
    device=$2
fi

# Check for hash
if [ ! -z "$3" ]
  then
    hash=$3
  else
    hash="sha-512"
fi
# Check for user
if [ ! -z "$4" ]
  then
    user=$4
  else
    user="root"
fi

# Warning, better safe than sorry
message "This script comes with zero warranty! Always backup your files! I'm not responsible for any data loss or damage!" $red

# Summary
message "Will use the following password: $passwd" $yellow
message "Will use the following device: $device \n" $yellow

# Check for permission
read -p "Are these information correct? (y/N) " continue
case "$continue" in
  No|no|N|n|"")
      message "Aborting!" $red
      exit 1
      ;;
      *)
      message "Let's rock!\n" $green
      ;;
esac

# Ask if we should remove old folders
read -p "Should a backup file be created in /openelec_backup ? (Y/n) " backup
case "$backup" in
  Yes|y|Y|yes|"")
      message "Will make a backup of the current image!" $yellow
      backup=true
      ;;
      *)
      message "Backup of current image will be skipped" $green
      remove=false
      ;;
esac

if [ ! -d /openelec_backup ]
  then
    mkdir /openelec_backup
fi

# Ask if we should remove old folders
read -p "Should the /openelec folders be removed after updating the password? (y/N) " remove
case "$remove" in
  No|no|N|n|"")
      message "Old folders won't be removed!" $yellow
      remove=false
      ;;
      *)
      message "Old folders will be removed" $green
      remove=true
      ;;
esac

# Remove folder
cd /
if [ -d /openelec ]
  then
    message "Found existing openelec folder" $yellow
    if [ "$remove" = true ]
      then
        message "Removing..." $yellow
        cleanUp
        message "Done\n" $green
      else
        message "You specified that old folder should not be removed." $yellow
        message "Please do this yourself now. Aborting..." $yellow
        exit 1
      fi
fi

# Setup
message "Making folders..." $yellow
mkdir /openelec
cd /openelec
mkdir flash original updated newsquashfs
message "Done\n" $green

# mount and copy suqashfs
message "Mounting openELEC squashfs system..." $yellow
mount /dev/$device /openelec/flash
if [ "$berryboot" = true ]
  then
    message "Listing the available files:"
    ls /openelec/flash/images/
    read -p "Please specify the openELEC file: " filename
    # See if file exists
    if [ ! -f /openelec/flash/images/$filename ]
      then
        message "Whoops, your $filename file is not there! Please check" $red
        message "Leaving $device mounted!" $red
        exit 1
    fi
    # Make a backup
    if [ "$backup" = true ]
      then
        # Unique pseudo timestamp
        date=$(date +"%Y%m%d-%T")
        if [ "$berryboot" ]
          then
            cp /openelec/flash/images/$filename /openelec_backup/$date-$filename
          else
            cp /openelec/flash/$filename /openelec_backup/$date-$filename
          fi
    fi
    # Loop already existing image
    mount -o loop /openelec/flash/images/$filename /openelec/original
  else
    # See if SYSTEM exists
    if [ ! -f /openelec/flash/$filename ]
      then
        message "Whoops, your SYSTEM file is not there! Please check" $red
        message "Leaving $device mounted!" $red
        exit 1
    fi

    # Mount loop to SYSTEM
    mount -o loop /openelec/flash/$filename /openelec/original
fi
message "Done\n" $green

# Copy files to temp folder
message "Copying files, this might take a moment..." $yellow
cp -a /openelec/original/* /openelec/updated
message "Done\n" $green

# Create new password
message "Generating a new password ($hash, random salt)..." $yellow
salt=$(cat /dev/urandom | tr -dc 'a-zA-Z0-9' | fold -w 16 | head -n 1)
shadow_password=$(mkpasswd $passwd --salt=$salt --method=$hash)
message "Done\n" $green

# Backup
message "Making backup from /etc/shadow and replace password..." $yellow
cd /openelec/updated/etc
mv shadow shadow.bak

# Replace second string for given user (default is root)
awk -v pw=$shadow_password -F: 'BEGIN{OFS=":"}/'$user'/{gsub(/.*/,pw,$2)}1' shadow.bak > shadow
message "Done\n" $green
# sed way
#sed -i.bak "/^$user:/ s/:[^:]*/:$shadow_password"

# Make new squashfs and unmount
message "Making new squashfs, this might take a bit..." $yellow
mksquashfs /openelec/updated/ /openelec/newsquashfs/$filename
message "Done\n" $green

# Copy updated squashfs back
message "Copying updated file back..." $yellow
if [ "$berryboot" = true ]
  then
    cp /openelec/newsquashfs/$filename /openelec/flash/images/$filename
  else
    cp /openelec/newsquashfs/$filename /openelec/flash/$filename
fi
message "Done\n" $green

# Clean
message "Unmounting openelec flash and original again..." $yellow
unmount
if [ "$remove" = true ]
  then
    message "Removing openelec folder again..." $yellow
    cleanUp
    message "Done\n\n" $green
fi

message "Your password was successfully updated. Please (unmount) and remove your device" $green

exit 0