DeDRM_tools/Calibre_Plugins/k4mobidedrm_plugin/mobidedrm.py

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#!/usr/bin/python
#
# This is a python script. You need a Python interpreter to run it.
# For example, ActiveState Python, which exists for windows.
#
# It can run standalone to convert files, or it can be installed as a
# plugin for Calibre (http://calibre-ebook.com/about) so that
# importing files with DRM 'Just Works'.
#
# To create a Calibre plugin, rename this file so that the filename
# ends in '_plugin.py', put it into a ZIP file and import that Calibre
# using its plugin configuration GUI.
#
# Changelog
# 0.01 - Initial version
# 0.02 - Huffdic compressed books were not properly decrypted
# 0.03 - Wasn't checking MOBI header length
# 0.04 - Wasn't sanity checking size of data record
# 0.05 - It seems that the extra data flags take two bytes not four
# 0.06 - And that low bit does mean something after all :-)
# 0.07 - The extra data flags aren't present in MOBI header < 0xE8 in size
# 0.08 - ...and also not in Mobi header version < 6
# 0.09 - ...but they are there with Mobi header version 6, header size 0xE4!
# 0.10 - Outputs unencrypted files as-is, so that when run as a Calibre
# import filter it works when importing unencrypted files.
# Also now handles encrypted files that don't need a specific PID.
# 0.11 - use autoflushed stdout and proper return values
# 0.12 - Fix for problems with metadata import as Calibre plugin, report errors
# 0.13 - Formatting fixes: retabbed file, removed trailing whitespace
# and extra blank lines, converted CR/LF pairs at ends of each line,
# and other cosmetic fixes.
# 0.14 - Working out when the extra data flags are present has been problematic
# Versions 7 through 9 have tried to tweak the conditions, but have been
# only partially successful. Closer examination of lots of sample
# files reveals that a confusin has arisen because trailing data entries
# are not encrypted, but it turns out that the multibyte entries
# in utf8 file are encrypted. (Although neither kind gets compressed.)
# This knowledge leads to a simplification of the test for the
# trailing data byte flags - version 5 and higher AND header size >= 0xE4.
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# 0.15 - Now outputs 'hearbeat', and is also quicker for long files.
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# 0.16 - And reverts to 'done' not 'done.' at the end for unswindle compatibility.
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# 0.17 - added modifications to support its use as an imported python module
# both inside calibre and also in other places (ie K4DeDRM tools)
# 0.17a - disabled the standalone plugin feature since a plugin can not import
# a plugin
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__version__ = '0.17'
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import sys
import struct
import binascii
class Unbuffered:
def __init__(self, stream):
self.stream = stream
def write(self, data):
self.stream.write(data)
self.stream.flush()
def __getattr__(self, attr):
return getattr(self.stream, attr)
class DrmException(Exception):
pass
# Implementation of Pukall Cipher 1
def PC1(key, src, decryption=True):
sum1 = 0;
sum2 = 0;
keyXorVal = 0;
if len(key)!=16:
print "Bad key length!"
return None
wkey = []
for i in xrange(8):
wkey.append(ord(key[i*2])<<8 | ord(key[i*2+1]))
dst = ""
for i in xrange(len(src)):
temp1 = 0;
byteXorVal = 0;
for j in xrange(8):
temp1 ^= wkey[j]
sum2 = (sum2+j)*20021 + sum1
sum1 = (temp1*346)&0xFFFF
sum2 = (sum2+sum1)&0xFFFF
temp1 = (temp1*20021+1)&0xFFFF
byteXorVal ^= temp1 ^ sum2
curByte = ord(src[i])
if not decryption:
keyXorVal = curByte * 257;
curByte = ((curByte ^ (byteXorVal >> 8)) ^ byteXorVal) & 0xFF
if decryption:
keyXorVal = curByte * 257;
for j in xrange(8):
wkey[j] ^= keyXorVal;
dst+=chr(curByte)
return dst
def checksumPid(s):
letters = "ABCDEFGHIJKLMNPQRSTUVWXYZ123456789"
crc = (~binascii.crc32(s,-1))&0xFFFFFFFF
crc = crc ^ (crc >> 16)
res = s
l = len(letters)
for i in (0,1):
b = crc & 0xff
pos = (b // l) ^ (b % l)
res += letters[pos%l]
crc >>= 8
return res
def getSizeOfTrailingDataEntries(ptr, size, flags):
def getSizeOfTrailingDataEntry(ptr, size):
bitpos, result = 0, 0
if size <= 0:
return result
while True:
v = ord(ptr[size-1])
result |= (v & 0x7F) << bitpos
bitpos += 7
size -= 1
if (v & 0x80) != 0 or (bitpos >= 28) or (size == 0):
return result
num = 0
testflags = flags >> 1
while testflags:
if testflags & 1:
num += getSizeOfTrailingDataEntry(ptr, size - num)
testflags >>= 1
# Multibyte data, if present, is included in the encryption, so
# we do not need to check the low bit.
# if flags & 1:
# num += (ord(ptr[size - num - 1]) & 0x3) + 1
return num
class DrmStripper:
def loadSection(self, section):
if (section + 1 == self.num_sections):
endoff = len(self.data_file)
else:
endoff = self.sections[section + 1][0]
off = self.sections[section][0]
return self.data_file[off:endoff]
def patch(self, off, new):
self.data_file = self.data_file[:off] + new + self.data_file[off+len(new):]
def patchSection(self, section, new, in_off = 0):
if (section + 1 == self.num_sections):
endoff = len(self.data_file)
else:
endoff = self.sections[section + 1][0]
off = self.sections[section][0]
assert off + in_off + len(new) <= endoff
self.patch(off + in_off, new)
def parseDRM(self, data, count, pid):
pid = pid.ljust(16,'\0')
keyvec1 = "\x72\x38\x33\xB0\xB4\xF2\xE3\xCA\xDF\x09\x01\xD6\xE2\xE0\x3F\x96"
temp_key = PC1(keyvec1, pid, False)
temp_key_sum = sum(map(ord,temp_key)) & 0xff
found_key = None
for i in xrange(count):
verification, size, type, cksum, cookie = struct.unpack('>LLLBxxx32s', data[i*0x30:i*0x30+0x30])
cookie = PC1(temp_key, cookie)
ver,flags,finalkey,expiry,expiry2 = struct.unpack('>LL16sLL', cookie)
if verification == ver and cksum == temp_key_sum and (flags & 0x1F) == 1:
found_key = finalkey
break
if not found_key:
# Then try the default encoding that doesn't require a PID
temp_key = keyvec1
temp_key_sum = sum(map(ord,temp_key)) & 0xff
for i in xrange(count):
verification, size, type, cksum, cookie = struct.unpack('>LLLBxxx32s', data[i*0x30:i*0x30+0x30])
cookie = PC1(temp_key, cookie)
ver,flags,finalkey,expiry,expiry2 = struct.unpack('>LL16sLL', cookie)
if verification == ver and cksum == temp_key_sum:
found_key = finalkey
break
return found_key
def __init__(self, data_file, pid):
if checksumPid(pid[0:-2]) != pid:
raise DrmException("invalid PID checksum")
pid = pid[0:-2]
self.data_file = data_file
header = data_file[0:72]
if header[0x3C:0x3C+8] != 'BOOKMOBI':
raise DrmException("invalid file format")
self.num_sections, = struct.unpack('>H', data_file[76:78])
self.sections = []
for i in xrange(self.num_sections):
offset, a1,a2,a3,a4 = struct.unpack('>LBBBB', data_file[78+i*8:78+i*8+8])
flags, val = a1, a2<<16|a3<<8|a4
self.sections.append( (offset, flags, val) )
sect = self.loadSection(0)
records, = struct.unpack('>H', sect[0x8:0x8+2])
mobi_length, = struct.unpack('>L',sect[0x14:0x18])
mobi_version, = struct.unpack('>L',sect[0x68:0x6C])
extra_data_flags = 0
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print "MOBI header version = %d, length = %d" %(mobi_version, mobi_length)
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if (mobi_length >= 0xE4) and (mobi_version >= 5):
extra_data_flags, = struct.unpack('>H', sect[0xF2:0xF4])
print "Extra Data Flags = %d" %extra_data_flags
crypto_type, = struct.unpack('>H', sect[0xC:0xC+2])
if crypto_type == 0:
print "This book is not encrypted."
else:
if crypto_type == 1:
raise DrmException("cannot decode Mobipocket encryption type 1")
if crypto_type != 2:
raise DrmException("unknown encryption type: %d" % crypto_type)
# calculate the keys
drm_ptr, drm_count, drm_size, drm_flags = struct.unpack('>LLLL', sect[0xA8:0xA8+16])
if drm_count == 0:
raise DrmException("no PIDs found in this file")
found_key = self.parseDRM(sect[drm_ptr:drm_ptr+drm_size], drm_count, pid)
if not found_key:
raise DrmException("no key found. maybe the PID is incorrect")
# kill the drm keys
self.patchSection(0, "\0" * drm_size, drm_ptr)
# kill the drm pointers
self.patchSection(0, "\xff" * 4 + "\0" * 12, 0xA8)
# clear the crypto type
self.patchSection(0, "\0" * 2, 0xC)
# decrypt sections
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print "Decrypting. Please wait . . .",
new_data = self.data_file[:self.sections[1][0]]
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for i in xrange(1, records+1):
data = self.loadSection(i)
extra_size = getSizeOfTrailingDataEntries(data, len(data), extra_data_flags)
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if i%100 == 0:
print ".",
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# print "record %d, extra_size %d" %(i,extra_size)
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new_data += PC1(found_key, data[0:len(data) - extra_size])
if extra_size > 0:
new_data += data[-extra_size:]
#self.patchSection(i, PC1(found_key, data[0:len(data) - extra_size]))
if self.num_sections > records+1:
new_data += self.data_file[self.sections[records+1][0]:]
self.data_file = new_data
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print "done"
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def getResult(self):
return self.data_file
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def getUnencryptedBook(infile,pid):
sys.stdout=Unbuffered(sys.stdout)
data_file = file(infile, 'rb').read()
strippedFile = DrmStripper(data_file, pid)
return strippedFile.getResult()
def main(argv=sys.argv):
sys.stdout=Unbuffered(sys.stdout)
print ('MobiDeDrm v%(__version__)s. '
'Copyright 2008-2010 The Dark Reverser.' % globals())
if len(argv)<4:
print "Removes protection from Mobipocket books"
print "Usage:"
print " %s <infile> <outfile> <PID>" % sys.argv[0]
return 1
else:
infile = argv[1]
outfile = argv[2]
pid = argv[3]
try:
stripped_file = getUnencryptedBook(infile, pid)
file(outfile, 'wb').write(stripped_file)
except DrmException, e:
print "Error: %s" % e
return 1
return 0
if __name__ == "__main__":
sys.exit(main())
#if not __name__ == "__main__":
if False:
# note a calibre plugin can not import code with another calibre plugin
# in it as it ends up registering two different plugins
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from calibre.customize import FileTypePlugin
class MobiDeDRM(FileTypePlugin):
name = 'MobiDeDRM' # Name of the plugin
description = 'Removes DRM from secure Mobi files'
supported_platforms = ['linux', 'osx', 'windows'] # Platforms this plugin will run on
author = 'The Dark Reverser' # The author of this plugin
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version = (0, 1, 7) # The version number of this plugin
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file_types = set(['prc','mobi','azw']) # The file types that this plugin will be applied to
on_import = True # Run this plugin during the import
def run(self, path_to_ebook):
from calibre.gui2 import is_ok_to_use_qt
from PyQt4.Qt import QMessageBox
PID = self.site_customization
data_file = file(path_to_ebook, 'rb').read()
ar = PID.split(',')
for i in ar:
try:
unlocked_file = DrmStripper(data_file, i).getResult()
except DrmException:
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if is_ok_to_use_qt():
d = QMessageBox(QMessageBox.Warning, "MobiDeDRM Plugin", "Error decoding: %s\n" % path_to_ebook)
d.show()
d.raise_()
d.exec_()
raise Exception("MobiDeDRM Plugin: Error decoding ebook")
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else:
of = self.temporary_file('.mobi')
of.write(unlocked_file)
of.close()
return of.name
def customization_help(self, gui=False):
return 'Enter PID (separate multiple PIDs with comma)'