DeDRM_tools/Calibre_Plugins/ignobleepub_plugin/__init__.py
Apprentice Alf b661a6cdc5 tools v5.4.1
2015-03-07 13:28:34 +00:00

342 lines
14 KiB
Python

#!/usr/bin/env python
# vim:fileencoding=UTF-8:ts=4:sw=4:sta:et:sts=4:ai
# -*- coding: utf-8 -*-
from __future__ import with_statement
__license__ = 'GPL v3'
__docformat__ = 'restructuredtext en'
# Released under the terms of the GNU General Public Licence, version 3 or
# later. <http://www.gnu.org/licenses/>
#
# Requires Calibre version 0.7.55 or higher.
#
# All credit given to I ♥ Cabbages for the original standalone scripts.
# I had the much easier job of converting them to Calibre a plugin.
#
# This plugin is meant to decrypt Barnes & Noble Epubs that are protected
# with a version of Adobe's Adept encryption. It is meant to function without having to
# install any dependencies... other than having Calibre installed, of course. It will still
# work if you have Python and PyCrypto already installed, but they aren't necessary.
#
# Configuration:
# Check out the plugin's configuration settings by clicking the "Customize plugin"
# button when you have the "BnN ePub DeDRM" plugin highlighted (under Preferences->
# Plugins->File type plugins). Once you have the configuration dialog open, you'll
# see a Help link on the top right-hand side.
#
# Revision history:
# 0.1.0 - Initial release
# 0.1.1 - Allow Windows users to make use of openssl if they have it installed.
# - Incorporated SomeUpdates zipfix routine.
# 0.1.2 - bug fix for non-ascii file names in encryption.xml
# 0.1.3 - Try PyCrypto on Windows first
# 0.1.4 - update zipfix to deal with mimetype not in correct place
# 0.1.5 - update zipfix to deal with completely missing mimetype files
# 0.1.6 - update for the new calibre plugin interface
# 0.1.7 - Fix for potential problem with PyCrypto
# 0.1.8 - an updated/modified zipfix.py and included zipfilerugged.py
# 0.2.0 - Completely overhauled plugin configuration dialog and key management/storage
# 0.2.1 - an updated/modified zipfix.py and included zipfilerugged.py
# 0.2.2 - added in potential fixes from 0.1.7 that had been missed.
# 0.2.3 - fixed possible output/unicode problem
# 0.2.4 - ditched nearly hopeless caselessStrCmp method in favor of uStrCmp.
# - added ability to rename existing keys.
"""
Decrypt Barnes & Noble ADEPT encrypted EPUB books.
"""
PLUGIN_NAME = 'Ignoble Epub DeDRM'
PLUGIN_VERSION_TUPLE = (0, 2, 4)
PLUGIN_VERSION = '.'.join([str(x) for x in PLUGIN_VERSION_TUPLE])
# Include an html helpfile in the plugin's zipfile with the following name.
RESOURCE_NAME = PLUGIN_NAME + '_Help.htm'
import sys, os, zlib, re
from zipfile import ZipFile, ZIP_STORED, ZIP_DEFLATED
from zipfile import ZipInfo as _ZipInfo
#from lxml import etree
try:
import xml.etree.cElementTree as etree
except ImportError:
import xml.etree.ElementTree as etree
from contextlib import closing
global AES
META_NAMES = ('mimetype', 'META-INF/rights.xml', 'META-INF/encryption.xml')
NSMAP = {'adept': 'http://ns.adobe.com/adept',
'enc': 'http://www.w3.org/2001/04/xmlenc#'}
class IGNOBLEError(Exception):
pass
def _load_crypto_libcrypto():
from ctypes import CDLL, POINTER, c_void_p, c_char_p, c_int, c_long, \
Structure, c_ulong, create_string_buffer, cast
from ctypes.util import find_library
if sys.platform.startswith('win'):
libcrypto = find_library('libeay32')
else:
libcrypto = find_library('crypto')
if libcrypto is None:
raise IGNOBLEError('%s Plugin v%s: libcrypto not found' % (PLUGIN_NAME, PLUGIN_VERSION))
libcrypto = CDLL(libcrypto)
AES_MAXNR = 14
c_char_pp = POINTER(c_char_p)
c_int_p = POINTER(c_int)
class AES_KEY(Structure):
_fields_ = [('rd_key', c_long * (4 * (AES_MAXNR + 1))),
('rounds', c_int)]
AES_KEY_p = POINTER(AES_KEY)
def F(restype, name, argtypes):
func = getattr(libcrypto, name)
func.restype = restype
func.argtypes = argtypes
return func
AES_set_decrypt_key = F(c_int, 'AES_set_decrypt_key',
[c_char_p, c_int, AES_KEY_p])
AES_cbc_encrypt = F(None, 'AES_cbc_encrypt',
[c_char_p, c_char_p, c_ulong, AES_KEY_p, c_char_p,
c_int])
class AES(object):
def __init__(self, userkey):
self._blocksize = len(userkey)
if (self._blocksize != 16) and (self._blocksize != 24) and (self._blocksize != 32) :
raise IGNOBLEError('%s Plugin v%s: AES improper key used' % (PLUGIN_NAME, PLUGIN_VERSION))
return
key = self._key = AES_KEY()
rv = AES_set_decrypt_key(userkey, len(userkey) * 8, key)
if rv < 0:
raise IGNOBLEError('%s Plugin v%s: Failed to initialize AES key' % (PLUGIN_NAME, PLUGIN_VERSION))
def decrypt(self, data):
out = create_string_buffer(len(data))
iv = ("\x00" * self._blocksize)
rv = AES_cbc_encrypt(data, out, len(data), self._key, iv, 0)
if rv == 0:
raise IGNOBLEError('%s Plugin v%s: AES decryption failed' % (PLUGIN_NAME, PLUGIN_VERSION))
return out.raw
print '%s Plugin v%s: Using libcrypto.' %(PLUGIN_NAME, PLUGIN_VERSION)
return AES
def _load_crypto_pycrypto():
from Crypto.Cipher import AES as _AES
class AES(object):
def __init__(self, key):
self._aes = _AES.new(key, _AES.MODE_CBC, '\x00'*16)
def decrypt(self, data):
return self._aes.decrypt(data)
print '%s Plugin v%s: Using PyCrypto.' %(PLUGIN_NAME, PLUGIN_VERSION)
return AES
def _load_crypto():
_aes = None
cryptolist = (_load_crypto_libcrypto, _load_crypto_pycrypto)
if sys.platform.startswith('win'):
cryptolist = (_load_crypto_pycrypto, _load_crypto_libcrypto)
for loader in cryptolist:
try:
_aes = loader()
break
except (ImportError, IGNOBLEError):
pass
return _aes
class ZipInfo(_ZipInfo):
def __init__(self, *args, **kwargs):
if 'compress_type' in kwargs:
compress_type = kwargs.pop('compress_type')
super(ZipInfo, self).__init__(*args, **kwargs)
self.compress_type = compress_type
class Decryptor(object):
def __init__(self, bookkey, encryption):
enc = lambda tag: '{%s}%s' % (NSMAP['enc'], tag)
self._aes = AES(bookkey)
encryption = etree.fromstring(encryption)
self._encrypted = encrypted = set()
expr = './%s/%s/%s' % (enc('EncryptedData'), enc('CipherData'),
enc('CipherReference'))
for elem in encryption.findall(expr):
path = elem.get('URI', None)
path = path.encode('utf-8')
if path is not None:
encrypted.add(path)
def decompress(self, bytes):
dc = zlib.decompressobj(-15)
bytes = dc.decompress(bytes)
ex = dc.decompress('Z') + dc.flush()
if ex:
bytes = bytes + ex
return bytes
def decrypt(self, path, data):
if path in self._encrypted:
data = self._aes.decrypt(data)[16:]
data = data[:-ord(data[-1])]
data = self.decompress(data)
return data
def plugin_main(userkey, inpath, outpath):
key = userkey.decode('base64')[:16]
aes = AES(key)
with closing(ZipFile(open(inpath, 'rb'))) as inf:
namelist = set(inf.namelist())
if 'META-INF/rights.xml' not in namelist or 'META-INF/encryption.xml' not in namelist:
print '%s Plugin: Not Encrypted.' % PLUGIN_NAME
return 1
for name in META_NAMES:
namelist.remove(name)
try: # If the generated keyfile doesn't match the bookkey, this is where it's likely to blow up.
rights = etree.fromstring(inf.read('META-INF/rights.xml'))
adept = lambda tag: '{%s}%s' % (NSMAP['adept'], tag)
expr = './/%s' % (adept('encryptedKey'),)
bookkey = ''.join(rights.findtext(expr))
bookkey = aes.decrypt(bookkey.decode('base64'))
bookkey = bookkey[:-ord(bookkey[-1])]
encryption = inf.read('META-INF/encryption.xml')
decryptor = Decryptor(bookkey[-16:], encryption)
kwds = dict(compression=ZIP_DEFLATED, allowZip64=False)
with closing(ZipFile(open(outpath, 'wb'), 'w', **kwds)) as outf:
zi = ZipInfo('mimetype', compress_type=ZIP_STORED)
outf.writestr(zi, inf.read('mimetype'))
for path in namelist:
data = inf.read(path)
outf.writestr(path, decryptor.decrypt(path, data))
except:
return 2
return 0
from calibre.customize import FileTypePlugin
from calibre.gui2 import is_ok_to_use_qt
class IgnobleDeDRM(FileTypePlugin):
name = PLUGIN_NAME
description = 'Removes DRM from secure Barnes & Noble epub files. Credit given to I ♥ Cabbages for the original stand-alone scripts.'
supported_platforms = ['linux', 'osx', 'windows']
author = 'DiapDealer'
version = PLUGIN_VERSION_TUPLE
minimum_calibre_version = (0, 7, 55) # Compiled python libraries cannot be imported in earlier versions.
file_types = set(['epub'])
on_import = True
def run(self, path_to_ebook):
from calibre_plugins.ignoble_epub import outputfix
if sys.stdout.encoding == None:
sys.stdout = outputfix.getwriter('utf-8')(sys.stdout)
else:
sys.stdout = outputfix.getwriter(sys.stdout.encoding)(sys.stdout)
if sys.stderr.encoding == None:
sys.stderr = outputfix.getwriter('utf-8')(sys.stderr)
else:
sys.stderr = outputfix.getwriter(sys.stderr.encoding)(sys.stderr)
global AES
print '\n\nRunning {0} v{1} on "{2}"'.format(PLUGIN_NAME, PLUGIN_VERSION, os.path.basename(path_to_ebook))
AES = _load_crypto()
if AES == None:
# Failed to load libcrypto or PyCrypto... Adobe Epubs can't be decrypted.'
raise Exception('%s Plugin v%s: Failed to load crypto libs.' % (PLUGIN_NAME, PLUGIN_VERSION))
# First time use or first time after upgrade to new key-handling/storage method
# or no keys configured. Give a visual prompt to configure.
import calibre_plugins.ignoble_epub.config as cfg
if not cfg.prefs['configured']:
titlemsg = '%s v%s' % (PLUGIN_NAME, PLUGIN_VERSION)
errmsg = titlemsg + ' not (properly) configured!\n' + \
'\nThis may be the first time you\'ve used this plugin' + \
' (or the first time since upgrading this plugin).' + \
' You\'ll need to open the customization dialog (Preferences->Plugins->File type plugins)' + \
' and follow the instructions there.\n' + \
'\nIf you don\'t use the ' + PLUGIN_NAME + ' plugin, you should disable or uninstall it.'
if is_ok_to_use_qt():
from PyQt4.Qt import QMessageBox
d = QMessageBox(QMessageBox.Warning, titlemsg, errmsg )
d.show()
d.raise_()
d.exec_()
raise Exception('%s Plugin v%s: Plugin not configured.' % (PLUGIN_NAME, PLUGIN_VERSION))
# Check original epub archive for zip errors.
from calibre_plugins.ignoble_epub import zipfix
inf = self.temporary_file('.epub')
try:
print '%s Plugin: Verifying zip archive integrity.' % PLUGIN_NAME
fr = zipfix.fixZip(path_to_ebook, inf.name)
fr.fix()
except Exception, e:
print '%s Plugin: unforeseen zip archive issue.' % PLUGIN_NAME
raise Exception(e)
# Create a TemporaryPersistent file to work with.
of = self.temporary_file('.epub')
# Attempt to decrypt epub with each encryption key (generated or provided).
key_counter = 1
for keyname, userkey in cfg.prefs['keys'].items():
keyname_masked = keyname[:4] + ''.join('x' for x in keyname[4:])
# Give the user key, ebook and TemporaryPersistent file to the Stripper function.
result = plugin_main(userkey, inf.name, of.name)
# Ebook is not a B&N Adept epub... do nothing and pass it on.
# This allows a non-encrypted epub to be imported without error messages.
if result == 1:
print '%s Plugin: Not a B&N Epub - doing nothing.\n' % PLUGIN_NAME
of.close()
return path_to_ebook
break
# Decryption was successful return the modified PersistentTemporary
# file to Calibre's import process.
if result == 0:
print '{0} Plugin: Encryption key {1} ("{2}") correct!'.format(PLUGIN_NAME, key_counter, keyname_masked)
of.close()
return of.name
break
print '{0} Plugin: Encryption key {1} ("{2}") incorrect!'.format(PLUGIN_NAME, key_counter, keyname_masked)
key_counter += 1
# Something went wrong with decryption.
# Import the original unmolested epub.
of.close
raise Exception('%s Plugin v%s: Ultimately failed to decrypt.\n' % (PLUGIN_NAME, PLUGIN_VERSION))
def is_customizable(self):
# return true to allow customization via the Plugin->Preferences.
return True
def config_widget(self):
from calibre_plugins.ignoble_epub.config import ConfigWidget
# Extract the helpfile contents from in the plugin's zipfile.
# The helpfile must be named <plugin name variable> + '_Help.htm'
return ConfigWidget(self.load_resources(RESOURCE_NAME)[RESOURCE_NAME])
def load_resources(self, names):
ans = {}
with ZipFile(self.plugin_path, 'r') as zf:
for candidate in zf.namelist():
if candidate in names:
ans[candidate] = zf.read(candidate)
return ans
def save_settings(self, config_widget):
config_widget.save_settings()