DEVELOPMENT.md

Most of the code is easy to understand. A few comments will help understand how a particular objective is achieved.
I will give a brief explanation of important functions in this file.

Format

• What does the function do?
• The logic behind the function.
• Issues and possible improvements for the function.

main()

Let's start with the main function. As soon as you run the program, you will be asked to select an option from a list.
If you select anything else, other than the provided options, a message to select valid options will be displayed.

I used case statements to make this work. The basic template for that is:

echo "Available actions: "
  echo "[1] Option 1"
  echo "[2] Option 2"

  read -p "Select your option: " option
  echo
  case $option in
  1)
    # Code for option 1
    ;;
  2)
    # Code for option 2
    ;;
  *)
    # Invalid option. Select from 1, 2.
    main
    ;;
  esac

The option validation of this case statement is given below.

input_valid=false
while [ "$input_valid" = false ]; do
  if main; then
    input_valid=true
  fi
done

This input validation part was taken from bard, so I have no idea how that works. But without it, you won't see anything when the script runs!

list_partitions()

This function checks and installs the tool lsblk, and displays the connected storage devices.
The user can select the mount point of the device on which they wish to execute operations like sanitization, extraction, or verification.

ins_tool_name()

Each tool has a different installation process. But most tools can be downloaded using sudo apt install $app.
This $app variable is used in many places, including the chk_install() function.

chk_install()

This function checks and notifies the user if a required command line utility is installed.

The logic used here is a simple version check command. Most linux tools show the version if a -v flag is given. If there is no output, then the tool is not installed.
But this logic fails with few tools that doesn't use -v or if the installation package name and executable package name are different for a tool.

For example, we use a command nanddump, in this program. But it is present in the installation package named mtd-utils. So, I gave below code in ins_nanddump() function:

app = "mtd-utils"
chk_install($app)

But the issue here is, the chk_install() function will check using mtd-utils -v. But we have to run nanddump -v, because mtd-utils is not an executable function. It will just return "command not found" error.

chk_umount()

It is important to unmount a device before performing any operations. So, I wrote this function to check if the mount point selected by the user is unmounted or not.

The logic used here is to check for the mount point in /proc/mounts. Any mounted device will appear there along with all it's partitions.
So, for example if the user wants to sanitize a device mounted as /dev/sda, we will check if the device is unmounted beforehand.
I introduced a variable $partition for this purpose. After taking partition="/dev/sda", we will check if $partition is present in /proc/mounts by using:

if grep -qs "$partition" /proc/mounts; then

The issue with this logic is that if the user gives a value that is not really a mount point, for example something like /not/real, then the function will check for it in /proc/mounts. It will not find it there, so it will be considered as successful unmounting.

A better logic is needed for this function.

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Cryptographic Wipe starts here

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veracrypt_encrypt()

This function simply uses the veracrypt tool to provide the user with a manual/automatic encryption option.
The user have to set the password which will be taken as $strongp, even in the automatic option.

chk_encrypted()

This function checks if the user-selected partition is already encrypted. If it is, the encryption of that drive is skipped.

The logic is for the name veracrypt in lsblk. Because, if the partition is already encrypted, it will be shown as veracrypt in lsblk.

wipe_disk()

This function overwrites the encrypted drive with a pass of random and zeroes each. Then formats the drive to ntfs once the user provides $name.

sudo dd if=/dev/random of=$partition bs=1M status=progress # overwriting with random values using dd
sudo dd if=/dev/zero of=$partition bs=1M status=progress > /dev/null 2>&1 # To suppress stdout

read -p "Set device name: " name
sudo mkfs.ntfs -L $name $partition # Format to ntfs filesystem

The mkfs.ntfs function only formats into ntfs filesystem. Improvements should be made here to format in other filesystems as per user requirement.

mount_disk()

This function simply creates a folder with the name the user provides for the sanitized drive, and mounts it at that location.
sudo mount $partition /media/$name

crypt_wipe()

This function just combines all the above individual steps of the cryptographic wipe process into a single function.
This will be used in the main function to make it less cluttered.

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Cryptographic Wipe ends here

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Secure Erase processes start here

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TODO: These processes should be updated here in the same way cryptographic wipe was added
Work in Progress...

chk_compat_hdparm()

This function checks if the selected storage device is compatible with hdparm commands.

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Secure Erase processes end here

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