DeDRM_tools/dedrm_src/kfxdedrm.py

116 lines
3.6 KiB
Python

#!/usr/bin/env python
# -*- coding: utf-8 -*-
from __future__ import with_statement
# Engine to remove drm from Kindle KFX ebooks
import os
import shutil
import zipfile
try:
from cStringIO import StringIO
except ImportError:
from StringIO import StringIO
try:
from calibre_plugins.dedrm import ion
except ImportError:
import ion
__license__ = 'GPL v3'
__version__ = '1.0'
class KFXZipBook:
def __init__(self, infile):
self.infile = infile
self.voucher = None
self.decrypted = {}
def getPIDMetaInfo(self):
return (None, None)
def processBook(self, totalpids):
with zipfile.ZipFile(self.infile, 'r') as zf:
for filename in zf.namelist():
with zf.open(filename) as fh:
data = fh.read(8)
if data != '\xeaDRMION\xee':
continue
data += fh.read()
if self.voucher is None:
self.decrypt_voucher(totalpids)
print u'Decrypting KFX DRMION: {0}'.format(filename)
outfile = StringIO()
ion.DrmIon(StringIO(data[8:-8]), lambda name: self.voucher).parse(outfile)
self.decrypted[filename] = outfile.getvalue()
if not self.decrypted:
print(u'The .kfx-zip archive does not contain an encrypted DRMION file')
def decrypt_voucher(self, totalpids):
with zipfile.ZipFile(self.infile, 'r') as zf:
for info in zf.infolist():
with zf.open(info.filename) as fh:
data = fh.read(4)
if data != '\xe0\x01\x00\xea':
continue
data += fh.read()
if 'ProtectedData' in data:
break # found DRM voucher
else:
raise Exception(u'The .kfx-zip archive contains an encrypted DRMION file without a DRM voucher')
print u'Decrypting KFX DRM voucher: {0}'.format(info.filename)
for pid in [''] + totalpids:
for dsn_len,secret_len in [(0,0), (16,0), (16,40), (32,40), (40,40)]:
if len(pid) == dsn_len + secret_len:
break # split pid into DSN and account secret
else:
continue
try:
voucher = ion.DrmIonVoucher(StringIO(data), pid[:dsn_len], pid[dsn_len:])
voucher.parse()
voucher.decryptvoucher()
break
except:
pass
else:
raise Exception(u'Failed to decrypt KFX DRM voucher with any key')
print u'KFX DRM voucher successfully decrypted'
license_type = voucher.getlicensetype()
if license_type != "Purchase":
raise Exception((u'This book is licensed as {0}. '
'These tools are intended for use on purchased books.').format(license_type))
self.voucher = voucher
def getBookTitle(self):
return os.path.splitext(os.path.split(self.infile)[1])[0]
def getBookExtension(self):
return '.kfx-zip'
def getBookType(self):
return 'KFX-ZIP'
def cleanup(self):
pass
def getFile(self, outpath):
if not self.decrypted:
shutil.copyfile(self.infile, outpath)
else:
with zipfile.ZipFile(self.infile, 'r') as zif:
with zipfile.ZipFile(outpath, 'w') as zof:
for info in zif.infolist():
zof.writestr(info, self.decrypted.get(info.filename, zif.read(info.filename)))