File size: 4,424 Bytes
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import os
import re
import sys
import json
import tqdm
import codecs
import random
import base64
import struct
import shutil
import requests
import tempfile
from Crypto.Cipher import AES
from Crypto.Util import Counter
sys.path.append(os.getcwd())
from main.app.variables import translations
def makebyte(x):
return codecs.latin_1_encode(x)[0]
def a32_to_str(a):
return struct.pack('>%dI' % len(a), *a)
def get_chunks(size):
p, s = 0, 0x20000
while p + s < size:
yield(p, s)
p += s
if s < 0x100000: s += 0x20000
yield(p, size - p)
def aes_cbc_decrypt(data, key):
aes_cipher = AES.new(key, AES.MODE_CBC, makebyte('\0' * 16))
return aes_cipher.decrypt(data)
def decrypt_attr(attr, key):
attr = codecs.latin_1_decode(aes_cbc_decrypt(attr, a32_to_str(key)))[0].rstrip('\0')
return json.loads(attr[4:]) if attr[:6] == 'MEGA{"' else False
def _api_request(data):
sequence_num = random.randint(0, 0xFFFFFFFF)
params = {'id': sequence_num}
sequence_num += 1
if not isinstance(data, list): data = [data]
response = requests.post(
'{0}://g.api.{1}/cs'.format('https', 'mega.co.nz'),
params=params,
data=json.dumps(data),
timeout=160
)
json_resp = json.loads(response.text)
if isinstance(json_resp, int): raise Exception(json_resp)
return json_resp[0]
def base64_url_decode(data):
data += '=='[(2 - len(data) * 3) % 4:]
for search, replace in (('-', '+'), ('_', '/'), (',', '')):
data = data.replace(search, replace)
return base64.b64decode(data)
def str_to_a32(b):
if isinstance(b, str): b = makebyte(b)
if len(b) % 4: b += b'\0' * (4 - len(b) % 4)
return struct.unpack('>%dI' % (len(b) / 4), b)
def base64_to_a32(s):
return str_to_a32(
base64_url_decode(s)
)
def mega_download_file(file_handle, file_key, dest_path=None):
file_key = base64_to_a32(file_key)
file_data = _api_request({'a': 'g', 'g': 1, 'p': file_handle})
k = (
file_key[0] ^ file_key[4],
file_key[1] ^ file_key[5],
file_key[2] ^ file_key[6],
file_key[3] ^ file_key[7]
)
iv = file_key[4:6] + (0, 0)
if 'g' not in file_data: raise Exception(translations["file_not_access"])
file_size = file_data['s']
attribs = decrypt_attr(base64_url_decode(file_data['at']), k)
input_file = requests.get(file_data['g'], stream=True).raw
temp_output_file = tempfile.NamedTemporaryFile(mode='w+b', prefix='megapy_', delete=False)
k_str = a32_to_str(k)
aes = AES.new(
k_str,
AES.MODE_CTR,
counter=Counter.new(
128,
initial_value=(
(iv[0] << 32) + iv[1]
) << 64
)
)
mac_str = b'\0' * 16
mac_encryptor = AES.new(k_str, AES.MODE_CBC, mac_str)
iv_str = a32_to_str([iv[0], iv[1], iv[0], iv[1]])
with tqdm.tqdm(total=file_size, ncols=100, unit="byte") as pbar:
for _, chunk_size in get_chunks(file_size):
chunk = aes.decrypt(input_file.read(chunk_size))
temp_output_file.write(chunk)
pbar.update(len(chunk))
encryptor = AES.new(k_str, AES.MODE_CBC, iv_str)
for i in range(0, len(chunk) - 16, 16):
block = chunk[i:i + 16]
encryptor.encrypt(block)
i = (i + 16) if file_size > 16 else 0
block = chunk[i:i + 16]
if len(block) % 16: block += b'\0' * (16 - (len(block) % 16))
mac_str = mac_encryptor.encrypt(encryptor.encrypt(block))
file_mac = str_to_a32(mac_str)
temp_output_file.close()
if (file_mac[0] ^ file_mac[1], file_mac[2] ^ file_mac[3]) != file_key[6:8]: raise ValueError(translations["mac_not_match"])
file_path = os.path.join(dest_path, attribs['n'])
if os.path.exists(file_path): os.remove(file_path)
shutil.move(temp_output_file.name, file_path)
return file_path
def mega_download_url(url, dest_path=None):
if '/file/' in url:
url = url.replace(' ', '')
file_id = re.findall(r'\W\w\w\w\w\w\w\w\w\W', url)[0][1:-1]
path = f'{file_id}!{url[re.search(file_id, url).end() + 1:]}'.split('!')
elif '!' in url: path = re.findall(r'/#!(.*)', url)[0].split('!')
else: raise Exception(translations["missing_url"])
return mega_download_file(path[0], path[1], dest_path) |