USB detection and blocker script for Linux Systems

usb_detect_blocker.sh

#!/bin/bash

# ==============================================================================
# Revert Ubuntu USB Security Policy
# ==============================================================================
#
# DESCRIPTION:
# This script reverts the changes made by the "Ubuntu USB Security Policy Script".
# It re-enables all USB devices and the Bluetooth service.
#
# FEATURES:
# 1. UDEV Rule Removal: Deletes the custom udev rule file.
# 2. Re-authorization: Explicitly re-authorizes all currently connected USB
#    devices, allowing them to work immediately.
# 3. Bluetooth Re-enable: Unmasks, enables, and starts the system Bluetooth
#    service.
#
# USAGE:
# 1. Stop the original security script if it is running (Ctrl+C).
# 2. Run this revert script with root privileges:
#    chmod +x revert_usb_security.sh
#    sudo ./revert_usb_security.sh
#
# ==============================================================================

# --- Configuration ---
UDEV_RULE_FILE="/etc/udev/rules.d/80-usb-security.rules"

# --- Main Revert Logic ---

# Ensure the script is run as root
if [ "$(id -u)" -ne 0 ]; then
    echo "This script must be run as root. Please use sudo."
    exit 1
fi

echo "--- Reverting USB Security Policy ---"

# 1. Re-enable Bluetooth Service
echo "[*] Re-enabling Bluetooth service..."
systemctl unmask bluetooth.service >/dev/null 2>&1
systemctl enable bluetooth.service >/dev/null 2>&1
systemctl start bluetooth.service >/dev/null 2>&1
echo "[+] Bluetooth service has been enabled and started."

# 2. Remove the UDEV rule file
if [ -f "$UDEV_RULE_FILE" ]; then
    echo "[*] Removing udev security rule file..."
    rm -f "$UDEV_RULE_FILE"
    echo "[+] Udev rule file deleted."
else
    echo "[!] Udev rule file not found. Skipping."
fi

# 3. Reload udev rules to remove the policy from memory
echo "[*] Reloading udev rules..."
udevadm control --reload-rules
echo "[+] Udev rules reloaded."

# 4. Re-authorize all currently connected USB devices
echo "[*] Re-authorizing all connected USB devices..."
for dir in /sys/bus/usb/devices/*; do
    if [ -f "$dir/authorized" ]; then
        # Writing 1 to 'authorized' re-enables the device
        echo 1 > "$dir/authorized"
    fi
done
echo "[+] All USB devices have been re-authorized."

# 5. Trigger udev to re-probe devices if necessary
udevadm trigger

echo -e "\n--- System Security Policy Reverted ---"
echo "Policy: All USB devices are now allowed."
echo "Bluetooth: Enabled and running."
echo "The system is back to its default USB device handling."
echo "----------------------------------------------------"