| import os | |
| import re | |
| import json | |
| import codecs | |
| import random | |
| import base64 | |
| import struct | |
| import shutil | |
| import requests | |
| import tempfile | |
| from Crypto.Cipher import AES | |
| from Crypto.Util import Counter | |
| 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] | |
| json_resp = json.loads(requests.post('{0}://g.api.{1}/cs'.format('https', 'mega.co.nz'), params=params, data=json.dumps(data), timeout=160).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 | |
| 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]]) | |
| for _, chunk_size in get_chunks(file_size): | |
| chunk = aes.decrypt(input_file.read(chunk_size)) | |
| temp_output_file.write(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 | |
| 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) | |
| 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 | |
| return mega_download_file(path[0], path[1], dest_path) |