69 lines
2.2 KiB
Python
69 lines
2.2 KiB
Python
|
from construct import RepeatUntil
|
||
|
|
from construct.core import Struct, Union
|
||
|
|
from construct.macros import *
|
||
|
|
from crypto.aes import AESdecryptCBC
|
||
|
|
from crypto.aeswrap import AESUnwrap
|
||
|
|
from zipfile import crc32
|
||
|
|
import struct
|
||
|
|
|
||
|
|
Dkey = 0x446B6579
|
||
|
|
EMF = 0x454D4621
|
||
|
|
BAG1 = 0x42414731
|
||
|
|
DONE = 0x444f4e45 #locker sentinel
|
||
|
|
#**** = 0x2A2A2A2A #wildcard for erase
|
||
|
|
|
||
|
|
#MAGIC (kL) | LEN (2bytes) | TAG (4) | DATA (LEN)
|
||
|
|
Locker = Struct("Locker",
|
||
|
|
String("magic",2),
|
||
|
|
ULInt16("length"),
|
||
|
|
Union("tag",
|
||
|
|
ULInt32("int"),
|
||
|
|
String("tag",4))
|
||
|
|
,
|
||
|
|
String("data", lambda ctx: ctx["length"])
|
||
|
|
)
|
||
|
|
|
||
|
|
Lockers = RepeatUntil(lambda obj, ctx: obj.tag.int == DONE, Locker)
|
||
|
|
|
||
|
|
def xor_strings(s, key):
|
||
|
|
res = ""
|
||
|
|
for i in xrange(len(s)):
|
||
|
|
res += chr(ord(s[i]) ^ ord(key[i%len(key)]))
|
||
|
|
return res
|
||
|
|
|
||
|
|
def check_effaceable_header(plog):
|
||
|
|
z = xor_strings(plog[:16], plog[16:32])
|
||
|
|
if z[:4] != "ecaF":
|
||
|
|
return False
|
||
|
|
plog_generation = struct.unpack("<L", plog[0x38:0x3C])[0]
|
||
|
|
print "Effaceable generation" , plog_generation
|
||
|
|
plog_crc = crc32(plog[0x40:0x40 + 960], crc32(plog[0x20:0x3C], crc32(z))) & 0xffffffff
|
||
|
|
assert plog_crc == struct.unpack("<L", plog[0x3C:0x40])[0] , "Effaceable CRC"
|
||
|
|
print "Effaceable CRC OK"
|
||
|
|
return True
|
||
|
|
|
||
|
|
class EffaceableLockers(object):
|
||
|
|
def __init__(self, data):
|
||
|
|
self.lockers = {}
|
||
|
|
for l in Lockers.parse(data):
|
||
|
|
tag = l.tag.int & ~0x80000000
|
||
|
|
tag = struct.pack("<L", tag)[::-1]
|
||
|
|
self.lockers[tag] = l.data
|
||
|
|
|
||
|
|
def display(self):
|
||
|
|
print "Lockers : " + ", ".join(sorted(self.lockers.keys()))
|
||
|
|
|
||
|
|
def get(self, tag):
|
||
|
|
return self.lockers.get(tag)
|
||
|
|
|
||
|
|
def get_DKey(self, k835):
|
||
|
|
if self.lockers.has_key("Dkey"):
|
||
|
|
return AESUnwrap(k835, self.lockers["Dkey"])
|
||
|
|
|
||
|
|
def get_EMF(self, k89b):
|
||
|
|
if self.lockers.has_key("LwVM"):
|
||
|
|
lwvm = AESdecryptCBC(self.lockers["LwVM"], k89b)
|
||
|
|
return lwvm[-32:]
|
||
|
|
elif self.lockers.has_key("EMF!"):
|
||
|
|
return AESdecryptCBC(self.lockers["EMF!"][4:], k89b)
|
||
|
|
|