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MobiDeDRM 0.23

This commit is contained in:
Apprentice Alf 2011-01-05 06:53:31 +00:00
parent a7856f5c32
commit 694dfafd39
1 changed files with 150 additions and 97 deletions
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247
KindleBooks_Tools/MobiDeDRM.py
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@ -41,12 +41,12 @@
# 0.19 - It seems that multibyte entries aren't encrypted in a v6 file either. # 0.19 - It seems that multibyte entries aren't encrypted in a v6 file either.
# 0.20 - Correction: It seems that multibyte entries are encrypted in a v6 file. # 0.20 - Correction: It seems that multibyte entries are encrypted in a v6 file.
# 0.21 - Added support for multiple pids # 0.21 - Added support for multiple pids
# 0.22 - revised structure to hold MobiBook as a class to allow an extended interface
# 0.23 - fixed problem with older files with no EXTH section
__version__ = '0.21' __version__ = '0.23'
import sys import sys
import struct
import binascii
class Unbuffered: class Unbuffered:
def __init__(self, stream): def __init__(self, stream):
@ -56,10 +56,19 @@ class Unbuffered:
self.stream.flush() self.stream.flush()
def __getattr__(self, attr): def __getattr__(self, attr):
return getattr(self.stream, attr) return getattr(self.stream, attr)
sys.stdout=Unbuffered(sys.stdout)
import struct
import binascii
class DrmException(Exception): class DrmException(Exception):
pass pass
#
# MobiBook Utility Routines
#
# Implementation of Pukall Cipher 1 # Implementation of Pukall Cipher 1
def PC1(key, src, decryption=True): def PC1(key, src, decryption=True):
sum1 = 0; sum1 = 0;
@ -71,7 +80,6 @@ def PC1(key, src, decryption=True):
wkey = [] wkey = []
for i in xrange(8): for i in xrange(8):
wkey.append(ord(key[i*2])<<8 | ord(key[i*2+1])) wkey.append(ord(key[i*2])<<8 | ord(key[i*2+1]))
dst = "" dst = ""
for i in xrange(len(src)): for i in xrange(len(src)):
temp1 = 0; temp1 = 0;
@ -132,7 +140,9 @@ def getSizeOfTrailingDataEntries(ptr, size, flags):
num += (ord(ptr[size - num - 1]) & 0x3) + 1 num += (ord(ptr[size - num - 1]) & 0x3) + 1
return num return num
class DrmStripper:
class MobiBook:
def loadSection(self, section): def loadSection(self, section):
if (section + 1 == self.num_sections): if (section + 1 == self.num_sections):
endoff = len(self.data_file) endoff = len(self.data_file)
@ -141,6 +151,83 @@ class DrmStripper:
off = self.sections[section][0] off = self.sections[section][0]
return self.data_file[off:endoff] return self.data_file[off:endoff]
def __init__(self, infile):
# initial sanity check on file
self.data_file = file(infile, 'rb').read()
self.header = self.data_file[0:78]
if self.header[0x3C:0x3C+8] != 'BOOKMOBI':
raise DrmException("invalid file format")
# build up section offset and flag info
self.num_sections, = struct.unpack('>H', self.header[76:78])
self.sections = []
for i in xrange(self.num_sections):
offset, a1,a2,a3,a4 = struct.unpack('>LBBBB', self.data_file[78+i*8:78+i*8+8])
flags, val = a1, a2<<16|a3<<8|a4
self.sections.append( (offset, flags, val) )
# parse information from section 0
self.sect = self.loadSection(0)
self.records, = struct.unpack('>H', self.sect[0x8:0x8+2])
self.mobi_length, = struct.unpack('>L',self.sect[0x14:0x18])
self.mobi_version, = struct.unpack('>L',self.sect[0x68:0x6C])
print "MOBI header version = %d, length = %d" %(self.mobi_version, self.mobi_length)
self.extra_data_flags = 0
if (self.mobi_length >= 0xE4) and (self.mobi_version >= 5):
self.extra_data_flags, = struct.unpack('>H', self.sect[0xF2:0xF4])
print "Extra Data Flags = %d" % self.extra_data_flags
if self.mobi_version < 7:
# multibyte utf8 data is included in the encryption for mobi_version 6 and below
# so clear that byte so that we leave it to be decrypted.
self.extra_data_flags &= 0xFFFE
# if exth region exists parse it for metadata array
self.meta_array = {}
try:
exth_flag, = struct.unpack('>L', self.sect[0x80:0x84])
exth = 'NONE'
if exth_flag & 0x40:
exth = self.sect[16 + self.mobi_length:]
if (len(exth) >= 4) and (exth[:4] == 'EXTH'):
nitems, = struct.unpack('>I', exth[8:12])
pos = 12
for i in xrange(nitems):
type, size = struct.unpack('>II', exth[pos: pos + 8])
content = exth[pos + 8: pos + size]
self.meta_array[type] = content
pos += size
except:
self.meta_array = {}
pass
def getBookTitle(self):
title = ''
if 503 in self.meta_array:
title = self.meta_array[503]
else :
toff, tlen = struct.unpack('>II', self.sect[0x54:0x5c])
tend = toff + tlen
title = self.sect[toff:tend]
if title == '':
title = self.header[:32]
title = title.split("\0")[0]
return title
def getPIDMetaInfo(self):
rec209 = None
token = None
if 209 in self.meta_array:
rec209 = self.meta_array[209]
data = rec209
# Parse the 209 data to find the the exth record with the token data.
# The last character of the 209 data points to the record with the token.
# Always 208 from my experience, but I'll leave the logic in case that changes.
for i in xrange(len(data)):
if ord(data[i]) != 0:
if self.meta_array[ord(data[i])] != None:
token = self.meta_array[ord(data[i])]
return rec209, token
def patch(self, off, new): def patch(self, off, new):
self.data_file = self.data_file[:off] + new + self.data_file[off+len(new):] self.data_file = self.data_file[:off] + new + self.data_file[off+len(new):]
@ -154,6 +241,7 @@ class DrmStripper:
self.patch(off + in_off, new) self.patch(off + in_off, new)
def parseDRM(self, data, count, pidlist): def parseDRM(self, data, count, pidlist):
found_key = None
keyvec1 = "\x72\x38\x33\xB0\xB4\xF2\xE3\xCA\xDF\x09\x01\xD6\xE2\xE0\x3F\x96" keyvec1 = "\x72\x38\x33\xB0\xB4\xF2\xE3\xCA\xDF\x09\x01\xD6\xE2\xE0\x3F\x96"
for pid in pidlist: for pid in pidlist:
bigpid = pid.ljust(16,'\0') bigpid = pid.ljust(16,'\0')
@ -185,111 +273,76 @@ class DrmStripper:
break break
return [found_key,pid] return [found_key,pid]
def __init__(self, data_file, pidlist): def processBook(self, pidlist):
# initial sanity check on file crypto_type, = struct.unpack('>H', self.sect[0xC:0xC+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
print "MOBI header version = %d, length = %d" %(mobi_version, mobi_length)
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
if mobi_version < 7:
# multibyte utf8 data is included in the encryption for mobi_version 6 and below
# so clear that byte so that we leave it to be decrypted.
extra_data_flags &= 0xFFFE
crypto_type, = struct.unpack('>H', sect[0xC:0xC+2])
if crypto_type == 0: if crypto_type == 0:
print "This book is not encrypted." print "This book is not encrypted."
else: return self.data_file
if crypto_type == 1: if crypto_type == 1:
raise DrmException("Cannot decode Mobipocket encryption type 1") raise DrmException("Cannot decode Mobipocket encryption type 1")
if crypto_type != 2: if crypto_type != 2:
raise DrmException("Cannot decode unknown Mobipocket encryption type %d" % crypto_type) raise DrmException("Cannot decode unknown Mobipocket encryption type %d" % crypto_type)
goodpids = [] goodpids = []
for pid in pidlist: for pid in pidlist:
if len(pid)==10: if len(pid)==10:
if checksumPid(pid[0:-2]) != pid: if checksumPid(pid[0:-2]) != pid:
print "PID " + pid + " has incorrect checksum, should have been "+checksumPid(pid[0:-2]) print "Warning: PID " + pid + " has incorrect checksum, should have been "+checksumPid(pid[0:-2])
else: goodpids.append(pid[0:-2])
goodpids.append(pid[0:-2]) elif len(pid)==8:
elif len(pid)==8: goodpids.append(pid)
print "PID without checksum given. With checksum PID is "+checksumPid(pid)
goodpids.append(pid)
if len(goodpids) == 0: # calculate the keys
raise DrmException("No valid PIDs supplied.") drm_ptr, drm_count, drm_size, drm_flags = struct.unpack('>LLLL', self.sect[0xA8:0xA8+16])
if drm_count == 0:
# calculate the keys raise DrmException("Not yet initialised with PID. Must be opened with Mobipocket Reader first.")
drm_ptr, drm_count, drm_size, drm_flags = struct.unpack('>LLLL', sect[0xA8:0xA8+16]) found_key, pid = self.parseDRM(self.sect[drm_ptr:drm_ptr+drm_size], drm_count, goodpids)
if drm_count == 0: if not found_key:
raise DrmException("Not yet initialised with PID. Must be opened with Mobipocket Reader first.") raise DrmException("No key found. Most likely the correct PID has not been given.")
found_key, pid = self.parseDRM(sect[drm_ptr:drm_ptr+drm_size], drm_count, goodpids)
if not found_key:
raise DrmException("No key found. Most likely the correct PID has not been given.")
if pid=="00000000": if pid=="00000000":
print "File has default encryption, no specific PID." print "File has default encryption, no specific PID."
else: else:
print "File is encoded with PID "+checksumPid(pid)+"." print "File is encoded with PID "+checksumPid(pid)+"."
# kill the drm keys # kill the drm keys
self.patchSection(0, "\0" * drm_size, drm_ptr) self.patchSection(0, "\0" * drm_size, drm_ptr)
# kill the drm pointers # kill the drm pointers
self.patchSection(0, "\xff" * 4 + "\0" * 12, 0xA8) self.patchSection(0, "\xff" * 4 + "\0" * 12, 0xA8)
# clear the crypto type # clear the crypto type
self.patchSection(0, "\0" * 2, 0xC) self.patchSection(0, "\0" * 2, 0xC)
# decrypt sections # decrypt sections
print "Decrypting. Please wait . . .", print "Decrypting. Please wait . . .",
new_data = self.data_file[:self.sections[1][0]] new_data = self.data_file[:self.sections[1][0]]
for i in xrange(1, records+1): for i in xrange(1, self.records+1):
data = self.loadSection(i) data = self.loadSection(i)
extra_size = getSizeOfTrailingDataEntries(data, len(data), extra_data_flags) extra_size = getSizeOfTrailingDataEntries(data, len(data), self.extra_data_flags)
if i%100 == 0: if i%100 == 0:
print ".", print ".",
# print "record %d, extra_size %d" %(i,extra_size) # print "record %d, extra_size %d" %(i,extra_size)
new_data += PC1(found_key, data[0:len(data) - extra_size]) new_data += PC1(found_key, data[0:len(data) - extra_size])
if extra_size > 0: if extra_size > 0:
new_data += data[-extra_size:] new_data += data[-extra_size:]
if self.num_sections > records+1: if self.num_sections > self.records+1:
new_data += self.data_file[self.sections[records+1][0]:] new_data += self.data_file[self.sections[self.records+1][0]:]
self.data_file = new_data self.data_file = new_data
print "done" print "done"
def getResult(self):
return self.data_file return self.data_file
def getUnencryptedBook(infile,pid): def getUnencryptedBook(infile,pid):
sys.stdout=Unbuffered(sys.stdout) if not os.path.isfile(infile):
data_file = file(infile, 'rb').read() raise DrmException('Input File Not Found')
strippedFile = DrmStripper(data_file, [pid]) book = MobiBook(infile)
return strippedFile.getResult() return book.processBook([pid])
def getUnencryptedBookWithList(infile,pidlist): def getUnencryptedBookWithList(infile,pidlist):
sys.stdout=Unbuffered(sys.stdout) if not os.path.isfile(infile):
data_file = file(infile, 'rb').read() raise DrmException('Input File Not Found')
strippedFile = DrmStripper(data_file, pidlist) book = MobiBook(infile)
return strippedFile.getResult() return book.processBook(pidlist)
def main(argv=sys.argv): def main(argv=sys.argv):
sys.stdout=Unbuffered(sys.stdout)
print ('MobiDeDrm v%(__version__)s. ' print ('MobiDeDrm v%(__version__)s. '
'Copyright 2008-2010 The Dark Reverser.' % globals()) 'Copyright 2008-2010 The Dark Reverser.' % globals())
if len(argv)<4: if len(argv)<4:
@ -302,7 +355,7 @@ def main(argv=sys.argv):
outfile = argv[2] outfile = argv[2]
pidlist = argv[3].split(',') pidlist = argv[3].split(',')
try: try:
stripped_file = getUnencryptedBook(infile, pidlist) stripped_file = getUnencryptedBookWithList(infile, pidlist)
file(outfile, 'wb').write(stripped_file) file(outfile, 'wb').write(stripped_file)
except DrmException, e: except DrmException, e:
print "Error: %s" % e print "Error: %s" % e