Hollow Knight PermaDeath changer

hk.py

#!/usr/bin/env python3
# -*- coding: utf-8 -*-

# Requires pycryptodome

import sys, os
if sys.version_info.major<3:
    sys.stderr.write("Python3 required\n")
    sys.exit(0)

import json, base64
from Crypto.Cipher import AES
from datetime import datetime


permadeathModes = {0:'Normal', 1:'Steel Soul', 2:'Steel Soul Broken 💀'}

header = bytes.fromhex('0001000000ffffffff01000000000000000601000000')
header_end = bytes([11])
key = b'UKu52ePUBwetZ9wNX88o54dnfKRu0T1l'
cipher = AES.new(key, AES.MODE_ECB)
modified = False

# https://msdn.microsoft.com/en-us/library/cc236844.aspx
def header_len(length):
    length = min(0x7fffffff, length); # maximum value

    x = []
    for i in range(4):
        if length >> 7 == 0:
            x.append(0x7f & length)
            length = length >> 7
            break
        else:
            x.append(0x7f & length | 0x80)
            length = length >> 7
    if length != 0:
        values.x(length)
    return bytes(x)


def decode(data):
    # Remove header
    data = data[len(header): len(data) - 1]

    for i in range(5):
        if ((data[i] & 0x80) == 0):
            break
    data = data[i+1:]

    data = base64.b64decode(data)
    data = cipher.decrypt(data)
    data = data[:-data[-1]] # Remove AES padding
    return data


def encode(data):
    # Add AES padding
    length = 16 - (len(data) % 16)
    data += bytes([length]) * length

    data = cipher.encrypt(data)
    data = base64.b64encode(data)

    # Add header
    data = header + header_len(len(data)) + data + header_end
    return data


# OPEN FILE
try:
	infile = open(sys.argv[1], mode="rb")
	data = infile.read()
	infile.close()
except:
	print("[-] Error opening file")
	exit()

# DECODE
data_decoded = decode(data)
y = json.loads(data_decoded)


# PRINT DATA
print('[VERSION] {0}'.format(y['playerData']['version']))
m,s = divmod(y['playerData']['playTime'], 60)
h,m = divmod(m, 60)
print('[playTime] {0:.0f} hours {1:.0f} minutes'.format(h,m))
print('[permadeathMode] {0}'.format(permadeathModes[y['playerData']['permadeathMode']]))
print('[💰] {0}'.format(y['playerData']['geo']))
print('[nailDamage] {0}'.format(y['playerData']['nailDamage']))
print('[completionPercentage] {0}%'.format(y['playerData']['completionPercentage']))


# Remove PermaDeath
if y['playerData']['permadeathMode'] == 2:
	print("💀💀 Reparing Steel Soul 💀💀")
	y['playerData']['permadeathMode'] = 1
	modified = True


if modified:

	data_encoded = encode(bytes(json.dumps(y), 'utf-8'))

	print('[+] Saving data backup')
	bakfile = open(sys.argv[1] + '_' + datetime.now().strftime('%Y%m%d%H%M%S') + '.bak', mode="wb")
	bakfile.write(data)
	infile.close()

	print('[+] Saving modified data')
	outfile = open(sys.argv[1], mode="wb")
	#outfile = open('output.txt', mode="wb")
	outfile.write(data_encoded)
	outfile.close()