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Add function crypto.interleave_xor_8.

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This commit is contained in:
Ethan Dalool 2020-03-23 20:40:30 -07:00
parent ae3bcbc9e4
commit a394f9829f
2 changed files with 8 additions and 15 deletions
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3
src/mega/crypto.py
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@ -137,6 +137,9 @@ def modular_inverse(a, m):
else: else:
return x % m return x % m
def interleave_xor_8(b):
return (b[0] ^ b[4], b[1] ^ b[5], b[2] ^ b[6], b[3] ^ b[7])
def base64_url_decode(data): def base64_url_decode(data):
data += '==' [(2 - len(data) * 3) % 4:] data += '==' [(2 - len(data) * 3) % 4:]
for search, replace in (('-', '+'), ('_', '/'), (',', '')): for search, replace in (('-', '+'), ('_', '/'), (',', '')):

20
src/mega/mega.py
View file

@ -23,7 +23,7 @@ from .crypto import (
a32_to_base64, encrypt_key, base64_url_encode, encrypt_attr, base64_to_a32, a32_to_base64, encrypt_key, base64_url_encode, encrypt_attr, base64_to_a32,
base64_url_decode, decrypt_attr, a32_to_str, get_chunks, str_to_a32, base64_url_decode, decrypt_attr, a32_to_str, get_chunks, str_to_a32,
decrypt_key, mpi_to_int, stringhash, prepare_key, make_id, makebyte, decrypt_key, mpi_to_int, stringhash, prepare_key, make_id, makebyte,
modular_inverse modular_inverse, interleave_xor_8
) )
logger = logging.getLogger(__name__) logger = logging.getLogger(__name__)
@ -274,10 +274,7 @@ class Mega:
file['shared_folder_key'] = shared_key file['shared_folder_key'] = shared_key
if key is not None: if key is not None:
if file['t'] == NODE_TYPE_FILE: if file['t'] == NODE_TYPE_FILE:
k = ( k = interleave_xor_8(key)
key[0] ^ key[4], key[1] ^ key[5], key[2] ^ key[6],
key[3] ^ key[7]
)
file['iv'] = key[4:6] + (0, 0) file['iv'] = key[4:6] + (0, 0)
file['meta_mac'] = key[6:8] file['meta_mac'] = key[6:8]
else: else:
@ -736,10 +733,7 @@ class Mega:
} }
file_data = self._api_request(request) file_data = self._api_request(request)
k = ( k = interleave_xor_8(file_key)
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) iv = file_key[4:6] + (0, 0)
meta_mac = file_key[6:8] meta_mac = file_key[6:8]
else: else:
@ -1190,9 +1184,7 @@ class Mega:
raise ValueError("Unexpected result", data) raise ValueError("Unexpected result", data)
key = base64_to_a32(file_key) key = base64_to_a32(file_key)
k = ( k = interleave_xor_8(key)
key[0] ^ key[4], key[1] ^ key[5], key[2] ^ key[6], key[3] ^ key[7]
)
size = data['s'] size = data['s']
unencrypted_attrs = decrypt_attr(base64_url_decode(data['at']), k) unencrypted_attrs = decrypt_attr(base64_url_decode(data['at']), k)
@ -1217,9 +1209,7 @@ class Mega:
dest_name = pl_info['name'] dest_name = pl_info['name']
key = base64_to_a32(file_key) key = base64_to_a32(file_key)
k = ( k = interleave_xor_8(key)
key[0] ^ key[4], key[1] ^ key[5], key[2] ^ key[6], key[3] ^ key[7]
)
encrypted_key = a32_to_base64(encrypt_key(key, self.master_key)) encrypted_key = a32_to_base64(encrypt_key(key, self.master_key))
encrypted_name = base64_url_encode(encrypt_attr({'n': dest_name}, k)) encrypted_name = base64_url_encode(encrypt_attr({'n': dest_name}, k))