#!/usr/bin/env python3 # -*- coding: utf-8 -*- # mobidedrm.py # Copyright © 2008 The Dark Reverser # Portions © 2008–2020 Apprentice Harper et al. from __future__ import print_function __license__ = 'GPL v3' __version__ = "1.1" # This is a python script. You need a Python interpreter to run it. # For example, ActiveState Python, which exists for windows. # # 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 confusion 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. # 0.15 - Now outputs 'heartbeat', and is also quicker for long files. # 0.16 - And reverts to 'done' not 'done.' at the end for unswindle compatibility. # 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 # 0.18 - It seems that multibyte entries aren't encrypted in a v7 file... # Removed the disabled Calibre plug-in code # Permit use of 8-digit PIDs # 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. # 0.21 - 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 # 0.24 - add support for type 1 encryption and 'TEXtREAd' books as well # 0.25 - Fixed support for 'BOOKMOBI' type 1 encryption # 0.26 - Now enables Text-To-Speech flag and sets clipping limit to 100% # 0.27 - Correct pid metadata token generation to match that used by skindle (Thank You Bart!) # 0.28 - slight additional changes to metadata token generation (None -> '') # 0.29 - It seems that the ideas about when multibyte trailing characters were # included in the encryption were wrong. They are for DOC compressed # files, but they are not for HUFF/CDIC compress files! # 0.30 - Modified interface slightly to work better with new calibre plugin style # 0.31 - The multibyte encrytion info is true for version 7 files too. # 0.32 - Added support for "Print Replica" Kindle ebooks # 0.33 - Performance improvements for large files (concatenation) # 0.34 - Performance improvements in decryption (libalfcrypto) # 0.35 - add interface to get mobi_version # 0.36 - fixed problem with TEXtREAd and getBookTitle interface # 0.37 - Fixed double announcement for stand-alone operation # 0.38 - Unicode used wherever possible, cope with absent alfcrypto # 0.39 - Fixed problem with TEXtREAd and getBookType interface # 0.40 - moved unicode_argv call inside main for Windows DeDRM compatibility # 0.41 - Fixed potential unicode problem in command line calls # 0.42 - Added GPL v3 licence. updated/removed some print statements # 1.0 - Python 3 compatibility for calibre 5.0 # 1.1 - Speed Python PC1 implementation up a little bit import sys import os import struct import binascii #@@CALIBRE_COMPAT_CODE@@ from .alfcrypto import Pukall_Cipher from .utilities import SafeUnbuffered from .argv_utils import unicode_argv class DrmException(Exception): pass # # MobiBook Utility Routines # # Implementation of Pukall Cipher 1 def PC1(key, src, decryption=True): # if we can get it from alfcrypto, use that try: return Pukall_Cipher().PC1(key,src,decryption) except: raise letters = b'ABCDEFGHIJKLMNPQRSTUVWXYZ123456789' def crc32(s): return (~binascii.crc32(s,-1))&0xFFFFFFFF def checksumPid(s): s = s.encode() crc = crc32(s) crc = crc ^ (crc >> 16) res = s l = len(letters) for i in (0,1): b = crc & 0xff pos = (b // l) ^ (b % l) res += bytes(bytearray([letters[pos%l]])) crc >>= 8 return res.decode() # expects bytearray def getSizeOfTrailingDataEntries(ptr, size, flags): def getSizeOfTrailingDataEntry(ptr, size): bitpos, result = 0, 0 if size <= 0: return result while True: if sys.version_info[0] == 2: v = ord(ptr[size-1]) else: v = 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 # Check the low bit to see if there's multibyte data present. # if multibyte data is included in the encryped data, we'll # have already cleared this flag. if flags & 1: if sys.version_info[0] == 2: num += (ord(ptr[size - num - 1]) & 0x3) + 1 else: num += (ptr[size - num - 1] & 0x3) + 1 return num class MobiBook: 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 cleanup(self): # to match function in Topaz book pass def __init__(self, infile): print("MobiDeDrm v{0:s}.\nCopyright © 2008-2022 The Dark Reverser, Apprentice Harper et al.".format(__version__)) # initial sanity check on file self.data_file = open(infile, 'rb').read() self.mobi_data = '' self.header = self.data_file[0:78] if self.header[0x3C:0x3C+8] != b'BOOKMOBI' and self.header[0x3C:0x3C+8] != b'TEXtREAd': raise DrmException("Invalid file format") self.magic = self.header[0x3C:0x3C+8] self.crypto_type = -1 # build up section offset and flag info self.num_sections, = struct.unpack('>H', self.header[76:78]) self.sections = [] for i in range(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.compression, = struct.unpack('>H', self.sect[0x0:0x0+2]) # det default values before PalmDoc test self.print_replica = False self.extra_data_flags = 0 self.meta_array = {} self.mobi_length = 0 self.mobi_codepage = 1252 self.mobi_version = -1 if self.magic == b'TEXtREAd': print("PalmDoc format book detected.") return self.mobi_length, = struct.unpack('>L',self.sect[0x14:0x18]) self.mobi_codepage, = struct.unpack('>L',self.sect[0x1c:0x20]) self.mobi_version, = struct.unpack('>L',self.sect[0x68:0x6C]) #print "MOBI header version {0:d}, header length {1:d}".format(self.mobi_version, self.mobi_length) 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: {0:d}".format(self.extra_data_flags) if (self.compression != 17480): # multibyte utf8 data is included in the encryption for PalmDoc compression # 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 try: exth_flag, = struct.unpack('>L', self.sect[0x80:0x84]) exth = b'' if exth_flag & 0x40: exth = self.sect[16 + self.mobi_length:] if (len(exth) >= 12) and (exth[:4] == b'EXTH'): nitems, = struct.unpack('>I', exth[8:12]) pos = 12 for i in range(nitems): type, size = struct.unpack('>II', exth[pos: pos + 8]) content = exth[pos + 8: pos + size] self.meta_array[type] = content # reset the text to speech flag and clipping limit, if present if type == 401 and size == 9: # set clipping limit to 100% self.patchSection(0, b'\144', 16 + self.mobi_length + pos + 8) elif type == 404 and size == 9: # make sure text to speech is enabled self.patchSection(0, b'\0', 16 + self.mobi_length + pos + 8) elif type == 405 and size == 9: # remove rented book flag self.patchSection(0, b'\0', 16 + self.mobi_length + pos + 8) elif type == 406 and size == 16: # remove rental due date self.patchSection(0, b'\0'*8, 16 + self.mobi_length + pos + 8) elif type == 208: # remove watermark (atv:kin: stuff) self.patchSection(0, b'\0'*(size-8), 16 + self.mobi_length + pos + 8) # print type, size, content, content.encode('hex') pos += size except Exception as e: print("Cannot set meta_array: Error: {:s}".format(e.args[0])) #returns unicode def getBookTitle(self): codec_map = { 1252 : 'windows-1252', 65001 : 'utf-8', } title = b'' codec = 'windows-1252' if self.magic == b'BOOKMOBI': 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 self.mobi_codepage in codec_map.keys(): codec = codec_map[self.mobi_codepage] if title == b'': title = self.header[:32] title = title.split(b'\0')[0] return title.decode(codec) def getPIDMetaInfo(self): rec209 = b'' token = b'' if 209 in self.meta_array: rec209 = self.meta_array[209] data = rec209 # The 209 data comes in five byte groups. Interpret the last four bytes # of each group as a big endian unsigned integer to get a key value # if that key exists in the meta_array, append its contents to the token for i in range(0,len(data),5): val, = struct.unpack('>I',data[i+1:i+5]) sval = self.meta_array.get(val,b'') token += sval return rec209, token # new must be byte array def patch(self, off, new): self.data_file = self.data_file[:off] + new + self.data_file[off+len(new):] # new must be byte array 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) # pids in pidlist must be unicode, returned key is byte array, pid is unicode def parseDRM(self, data, count, pidlist): found_key = None keyvec1 = b'\x72\x38\x33\xB0\xB4\xF2\xE3\xCA\xDF\x09\x01\xD6\xE2\xE0\x3F\x96' for pid in pidlist: bigpid = pid.encode('utf-8').ljust(16,b'\0') temp_key = PC1(keyvec1, bigpid, False) if sys.version_info[0] == 2: temp_key_sum = sum(map(ord,temp_key)) & 0xff else: temp_key_sum = sum(temp_key) & 0xff found_key = None for i in range(count): verification, size, type, cksum, cookie = struct.unpack('>LLLBxxx32s', data[i*0x30:i*0x30+0x30]) if cksum == temp_key_sum: cookie = PC1(temp_key, cookie) ver,flags,finalkey,expiry,expiry2 = struct.unpack('>LL16sLL', cookie) if verification == ver and (flags & 0x1F) == 1: found_key = finalkey break if found_key != None: break if not found_key: # Then try the default encoding that doesn't require a PID pid = '00000000' temp_key = keyvec1 if sys.version_info[0] == 2: temp_key_sum = sum(map(ord,temp_key)) & 0xff else: temp_key_sum = sum(temp_key) & 0xff for i in range(count): verification, size, type, cksum, cookie = struct.unpack('>LLLBxxx32s', data[i*0x30:i*0x30+0x30]) if cksum == temp_key_sum: cookie = PC1(temp_key, cookie) ver,flags,finalkey,expiry,expiry2 = struct.unpack('>LL16sLL', cookie) if verification == ver: found_key = finalkey break return [found_key,pid] def getFile(self, outpath): open(outpath,'wb').write(self.mobi_data) def getBookType(self): if self.print_replica: return "Print Replica" if self.mobi_version >= 8: return "Kindle Format 8" if self.mobi_version >= 0: return "Mobipocket {0:d}".format(self.mobi_version) return "PalmDoc" def getBookExtension(self): if self.print_replica: return ".azw4" if self.mobi_version >= 8: return ".azw3" return ".mobi" # pids in pidlist may be unicode or bytearrays or bytes def processBook(self, pidlist): crypto_type, = struct.unpack('>H', self.sect[0xC:0xC+2]) print("Crypto Type is: {0:d}".format(crypto_type)) self.crypto_type = crypto_type if crypto_type == 0: print("This book is not encrypted.") # we must still check for Print Replica self.print_replica = (self.loadSection(1)[0:4] == b'%MOP') self.mobi_data = self.data_file return if crypto_type != 2 and crypto_type != 1: raise DrmException("Cannot decode unknown Mobipocket encryption type {0:d}".format(crypto_type)) if 406 in self.meta_array: data406 = self.meta_array[406] val406, = struct.unpack('>Q',data406) if val406 != 0: print("Warning: This is a library or rented ebook ({0}). Continuing ...".format(val406)) #raise DrmException("Cannot decode library or rented ebooks.") goodpids = [] # print("DEBUG ==== pidlist = ", pidlist) for pid in pidlist: if isinstance(pid,(bytearray,bytes)): pid = pid.decode('utf-8') if len(pid)==10: if checksumPid(pid[0:-2]) != pid: print("Warning: PID {0} has incorrect checksum, should have been {1}".format(pid,checksumPid(pid[0:-2]))) goodpids.append(pid[0:-2]) elif len(pid)==8: goodpids.append(pid) else: print("Warning: PID {0} has wrong number of digits".format(pid)) # print("======= DEBUG good pids = ", goodpids) if self.crypto_type == 1: t1_keyvec = b'QDCVEPMU675RUBSZ' if self.magic == b'TEXtREAd': bookkey_data = self.sect[0x0E:0x0E+16] elif self.mobi_version < 0: bookkey_data = self.sect[0x90:0x90+16] else: bookkey_data = self.sect[self.mobi_length+16:self.mobi_length+32] pid = '00000000' found_key = PC1(t1_keyvec, bookkey_data) else : # calculate the keys drm_ptr, drm_count, drm_size, drm_flags = struct.unpack('>LLLL', self.sect[0xA8:0xA8+16]) if drm_count == 0: raise DrmException("Encryption not initialised. Must be opened with Mobipocket Reader first.") found_key, pid = self.parseDRM(self.sect[drm_ptr:drm_ptr+drm_size], drm_count, goodpids) if not found_key: raise DrmException("No key found in {0:d} PIDs tried.".format(len(goodpids))) # kill the drm keys self.patchSection(0, b'\0' * drm_size, drm_ptr) # kill the drm pointers self.patchSection(0, b'\xff' * 4 + b'\0' * 12, 0xA8) if pid=='00000000': print("File has default encryption, no specific key needed.") else: print("File is encoded with PID {0}.".format(checksumPid(pid))) # clear the crypto type self.patchSection(0, b'\0' * 2, 0xC) # decrypt sections print("Decrypting. Please wait . . .", end=' ') mobidataList = [] mobidataList.append(self.data_file[:self.sections[1][0]]) for i in range(1, self.records+1): data = self.loadSection(i) extra_size = getSizeOfTrailingDataEntries(data, len(data), self.extra_data_flags) if i%100 == 0: print(".", end=' ') # print "record %d, extra_size %d" %(i,extra_size) decoded_data = PC1(found_key, data[0:len(data) - extra_size]) if i==1: self.print_replica = (decoded_data[0:4] == b'%MOP') mobidataList.append(decoded_data) if extra_size > 0: mobidataList.append(data[-extra_size:]) if self.num_sections > self.records+1: mobidataList.append(self.data_file[self.sections[self.records+1][0]:]) self.mobi_data = b''.join(mobidataList) print("done") return # pids in pidlist must be unicode def getUnencryptedBook(infile,pidlist): if not os.path.isfile(infile): raise DrmException("Input File Not Found.") book = MobiBook(infile) book.processBook(pidlist) return book.mobi_data def cli_main(): argv=unicode_argv("mobidedrm.py") progname = os.path.basename(argv[0]) if len(argv)<3 or len(argv)>4: print("MobiDeDrm v{0:s}.\nCopyright © 2008-2020 The Dark Reverser, Apprentice Harper et al.".format(__version__)) print("Removes protection from Kindle/Mobipocket, Kindle/KF8 and Kindle/Print Replica ebooks") print("Usage:") print(" {0} []".format(progname)) return 1 else: infile = argv[1] outfile = argv[2] if len(argv) == 4: pidlist = argv[3].split(',') else: pidlist = [] try: stripped_file = getUnencryptedBook(infile, pidlist) open(outfile, 'wb').write(stripped_file) except DrmException as e: print("MobiDeDRM v{0} Error: {1:s}".format(__version__,e.args[0])) return 1 return 0 if __name__ == '__main__': sys.stdout=SafeUnbuffered(sys.stdout) sys.stderr=SafeUnbuffered(sys.stderr) sys.exit(cli_main())