ntfauth-cmdi_REDACTED.py

#!/usr/bin/env python
import RPi.GPIO as GPIO
import mfrc522
import subprocess
import time
import RGB1602

# Secrets!
DEFAULT_KEY = [0xFF,0xFF,0xFF,0xFF,0xFF,0xFF]
KEY = "REDACTED"
ADMIN_GROUP = "REDACTED"

# Display function on the screen.
lcd=RGB1602.RGB1602(16,2)
def disp(line1,line2,r,g,b):
    lcd.setCursor(0, 0)
    lcd.printout(line1)
    lcd.setCursor(0, 1)
    lcd.printout(line2)
    lcd.setRGB(r,g,b);

# Print flag on the display with a sliding effect.
def disp_file(file):
    with open(file) as f:
        lines = f.readlines()

    # Print the first 16 caracters for 2 seconds.
    disp("Auth. Success  ",lines[0][0:16],144,249,15)
    time.sleep(2)

    # Slide to next chars of the first line..
    for i in range(1,len(lines[0])-16):
        disp("Auth. Success  ",lines[0][i:i+16],144,249,15)
        time.sleep(0.4)

    # Keep display for an additional few seconds.
    time.sleep(5)

def format_uid(uid):
    s = ""
    for i in range(0, len(uid)):
        s += "%x" % uid[i]
    return s.upper()

# Initiate NFC reader.
RFID = mfrc522.MFRC522()

# Get tag size if available.
(Status, TagSize) = RFID.MFRC522_Request(RFID.PICC_REQIDL)

# Privileges information are in sector 1.
Sector = 1

while True:

    # Display main message.
    print("Waiting for Tag...\n")
    disp("Waiting tags...  ","                ",255,255,255)

    while True:

        # Try to get NFC data.
        (Status, TagSize) = RFID.MFRC522_Request(RFID.PICC_REQIDL)
        if Status != RFID.MI_OK:
            continue

        if TagSize < 1:
            print("Can't read tag properly!")
            disp("Error!          ","Can't read tag! ",255,0,0)
            time.sleep(1)
            break

        if Sector < 1 or Sector > (TagSize - 1):
            print("Sector out of range (1 - %s)\n" % (TagSize - 1))
            disp("Error!          ","Sector range!",255,0,0)
            time.sleep(1)
            break

        # Selecting blocks.
        BaseBlockLength = 4
        if Sector < 32:
            BlockLength = BaseBlockLength
            StartAddr = Sector * BlockLength
        else:
            BlockLength = 16
            StartAddr = 32 * BaseBlockLength + (Sector - 32) * BlockLength

        BlockAddrs = []
        for i in range(0, (BlockLength - 1)):
            BlockAddrs.append((StartAddr + i))
        TrailerBlockAddr = (StartAddr + (BlockLength - 1))

        # Initializing tag.
        (Status, UID) = RFID.MFRC522_Anticoll()
        if Status != RFID.MI_OK:
            break

        # Reading sector and parsing retrieved data.
        RFID.MFRC522_SelectTag(UID)
        Status = RFID.MFRC522_Auth(RFID.PICC_AUTHENT1A, TrailerBlockAddr, KEY, UID)
        data = []
        text_read = ""
        if Status == RFID.MI_OK:
            for block_num in BlockAddrs:
                block = RFID.MFRC522_Read(block_num)
                if block:
                    data += block
            if data:
                text_read = "".join(chr(i) for i in data)
            print("UID:  ", format_uid(UID))
            print("Data: ", text_read,"\n")

            # Extract username
            if text_read.count("user=") > 0:
                user=text_read.split("=",1)[1]
                print(user)

                # Retrieve associated group.
                output,retcode = subprocess.Popen("groups {}".format(user), shell=True, stdout=subprocess.PIPE).communicate()
                groups=output.decode('utf-8')

                # Check user privileges.
                if groups.count(ADMIN_GROUP) > 0:
                    print("[+] Success!")
                    disp_file('flag.txt')
                else:
                    print("[-] Error, user do not have the proper group ...")
                    disp("Wrong group...   ",groups[0:15],255,0,0)
                    time.sleep(5)
            else:
                print("[-] Error, no user entry !")
                disp("Error!          ","No user entry...",255,0,0)
                time.sleep(1)
        else:
            print("[-] Can't access sector", Sector, "!\n")
            disp("Error!          ","Sector access...",255,0,0)
            time.sleep(1)
        RFID.MFRC522_StopCrypto1()
        break

RFID.AntennaOff()
GPIO.cleanup()