DeDRM_tools/ineptpdf.pyw
2015-02-27 06:54:12 +00:00

1570 lines
48 KiB
Python

#! /usr/bin/python
# ineptpdf.pyw, version 2
# To run this program install Python 2.6 from http://www.python.org/download/
# and PyCrypto from http://www.voidspace.org.uk/python/modules.shtml#pycrypto
# (make sure to install the version for Python 2.6). Save this script file as
# ineptpdf.pyw and double-click on it to run it.
# Revision history:
# 1 - Initial release
# 2 - Improved determination of key-generation algorithm
"""
Decrypt Adobe ADEPT-encrypted PDF files.
"""
from __future__ import with_statement
__license__ = 'GPL v3'
import sys
import os
import re
import zlib
import struct
import hashlib
from itertools import chain
import xml.etree.ElementTree as etree
import Tkinter
import Tkconstants
import tkFileDialog
import tkMessageBox
try:
from Crypto.Cipher import ARC4
from Crypto.PublicKey import RSA
except ImportError:
ARC4 = None
RSA = None
class ADEPTError(Exception):
pass
###
### ASN.1 parsing code from tlslite
def bytesToNumber(bytes):
total = 0L
for byte in bytes:
total = (total << 8) + byte
return total
class ASN1Error(Exception):
pass
class ASN1Parser(object):
class Parser(object):
def __init__(self, bytes):
self.bytes = bytes
self.index = 0
def get(self, length):
if self.index + length > len(self.bytes):
raise ASN1Error("Error decoding ASN.1")
x = 0
for count in range(length):
x <<= 8
x |= self.bytes[self.index]
self.index += 1
return x
def getFixBytes(self, lengthBytes):
bytes = self.bytes[self.index : self.index+lengthBytes]
self.index += lengthBytes
return bytes
def getVarBytes(self, lengthLength):
lengthBytes = self.get(lengthLength)
return self.getFixBytes(lengthBytes)
def getFixList(self, length, lengthList):
l = [0] * lengthList
for x in range(lengthList):
l[x] = self.get(length)
return l
def getVarList(self, length, lengthLength):
lengthList = self.get(lengthLength)
if lengthList % length != 0:
raise ASN1Error("Error decoding ASN.1")
lengthList = int(lengthList/length)
l = [0] * lengthList
for x in range(lengthList):
l[x] = self.get(length)
return l
def startLengthCheck(self, lengthLength):
self.lengthCheck = self.get(lengthLength)
self.indexCheck = self.index
def setLengthCheck(self, length):
self.lengthCheck = length
self.indexCheck = self.index
def stopLengthCheck(self):
if (self.index - self.indexCheck) != self.lengthCheck:
raise ASN1Error("Error decoding ASN.1")
def atLengthCheck(self):
if (self.index - self.indexCheck) < self.lengthCheck:
return False
elif (self.index - self.indexCheck) == self.lengthCheck:
return True
else:
raise ASN1Error("Error decoding ASN.1")
def __init__(self, bytes):
p = self.Parser(bytes)
p.get(1)
self.length = self._getASN1Length(p)
self.value = p.getFixBytes(self.length)
def getChild(self, which):
p = self.Parser(self.value)
for x in range(which+1):
markIndex = p.index
p.get(1)
length = self._getASN1Length(p)
p.getFixBytes(length)
return ASN1Parser(p.bytes[markIndex:p.index])
def _getASN1Length(self, p):
firstLength = p.get(1)
if firstLength<=127:
return firstLength
else:
lengthLength = firstLength & 0x7F
return p.get(lengthLength)
###
### PDF parsing routines from pdfminer, with changes for EBX_HANDLER
## Utilities
##
def choplist(n, seq):
'''Groups every n elements of the list.'''
r = []
for x in seq:
r.append(x)
if len(r) == n:
yield tuple(r)
r = []
return
def nunpack(s, default=0):
'''Unpacks up to 4 bytes big endian.'''
l = len(s)
if not l:
return default
elif l == 1:
return ord(s)
elif l == 2:
return unpack('>H', s)[0]
elif l == 3:
return unpack('>L', '\x00'+s)[0]
elif l == 4:
return unpack('>L', s)[0]
else:
return TypeError('invalid length: %d' % l)
STRICT = 0
## PS Exceptions
##
class PSException(Exception): pass
class PSEOF(PSException): pass
class PSSyntaxError(PSException): pass
class PSTypeError(PSException): pass
class PSValueError(PSException): pass
## Basic PostScript Types
##
# PSLiteral
class PSObject(object): pass
class PSLiteral(PSObject):
'''
PS literals (e.g. "/Name").
Caution: Never create these objects directly.
Use PSLiteralTable.intern() instead.
'''
def __init__(self, name):
self.name = name
return
def __repr__(self):
name = []
for char in self.name:
if not char.isalnum():
char = '#%02x' % ord(char)
name.append(char)
return '/%s' % ''.join(name)
# PSKeyword
class PSKeyword(PSObject):
'''
PS keywords (e.g. "showpage").
Caution: Never create these objects directly.
Use PSKeywordTable.intern() instead.
'''
def __init__(self, name):
self.name = name
return
def __repr__(self):
return self.name
# PSSymbolTable
class PSSymbolTable(object):
'''
Symbol table that stores PSLiteral or PSKeyword.
'''
def __init__(self, classe):
self.dic = {}
self.classe = classe
return
def intern(self, name):
if name in self.dic:
lit = self.dic[name]
else:
lit = self.classe(name)
self.dic[name] = lit
return lit
PSLiteralTable = PSSymbolTable(PSLiteral)
PSKeywordTable = PSSymbolTable(PSKeyword)
LIT = PSLiteralTable.intern
KWD = PSKeywordTable.intern
KEYWORD_BRACE_BEGIN = KWD('{')
KEYWORD_BRACE_END = KWD('}')
KEYWORD_ARRAY_BEGIN = KWD('[')
KEYWORD_ARRAY_END = KWD(']')
KEYWORD_DICT_BEGIN = KWD('<<')
KEYWORD_DICT_END = KWD('>>')
def literal_name(x):
if not isinstance(x, PSLiteral):
if STRICT:
raise PSTypeError('Literal required: %r' % x)
else:
return str(x)
return x.name
def keyword_name(x):
if not isinstance(x, PSKeyword):
if STRICT:
raise PSTypeError('Keyword required: %r' % x)
else:
return str(x)
return x.name
## PSBaseParser
##
EOL = re.compile(r'[\r\n]')
SPC = re.compile(r'\s')
NONSPC = re.compile(r'\S')
HEX = re.compile(r'[0-9a-fA-F]')
END_LITERAL = re.compile(r'[#/%\[\]()<>{}\s]')
END_HEX_STRING = re.compile(r'[^\s0-9a-fA-F]')
HEX_PAIR = re.compile(r'[0-9a-fA-F]{2}|.')
END_NUMBER = re.compile(r'[^0-9]')
END_KEYWORD = re.compile(r'[#/%\[\]()<>{}\s]')
END_STRING = re.compile(r'[()\134]')
OCT_STRING = re.compile(r'[0-7]')
ESC_STRING = { 'b':8, 't':9, 'n':10, 'f':12, 'r':13, '(':40, ')':41, '\\':92 }
class PSBaseParser(object):
'''
Most basic PostScript parser that performs only basic tokenization.
'''
BUFSIZ = 4096
def __init__(self, fp):
self.fp = fp
self.seek(0)
return
def __repr__(self):
return '<PSBaseParser: %r, bufpos=%d>' % (self.fp, self.bufpos)
def flush(self):
return
def close(self):
self.flush()
return
def tell(self):
return self.bufpos+self.charpos
def poll(self, pos=None, n=80):
pos0 = self.fp.tell()
if not pos:
pos = self.bufpos+self.charpos
self.fp.seek(pos)
print >>sys.stderr, 'poll(%d): %r' % (pos, self.fp.read(n))
self.fp.seek(pos0)
return
def seek(self, pos):
'''
Seeks the parser to the given position.
'''
self.fp.seek(pos)
# reset the status for nextline()
self.bufpos = pos
self.buf = ''
self.charpos = 0
# reset the status for nexttoken()
self.parse1 = self.parse_main
self.tokens = []
return
def fillbuf(self):
if self.charpos < len(self.buf): return
# fetch next chunk.
self.bufpos = self.fp.tell()
self.buf = self.fp.read(self.BUFSIZ)
if not self.buf:
raise PSEOF('Unexpected EOF')
self.charpos = 0
return
def parse_main(self, s, i):
m = NONSPC.search(s, i)
if not m:
return (self.parse_main, len(s))
j = m.start(0)
c = s[j]
self.tokenstart = self.bufpos+j
if c == '%':
self.token = '%'
return (self.parse_comment, j+1)
if c == '/':
self.token = ''
return (self.parse_literal, j+1)
if c in '-+' or c.isdigit():
self.token = c
return (self.parse_number, j+1)
if c == '.':
self.token = c
return (self.parse_float, j+1)
if c.isalpha():
self.token = c
return (self.parse_keyword, j+1)
if c == '(':
self.token = ''
self.paren = 1
return (self.parse_string, j+1)
if c == '<':
self.token = ''
return (self.parse_wopen, j+1)
if c == '>':
self.token = ''
return (self.parse_wclose, j+1)
self.add_token(KWD(c))
return (self.parse_main, j+1)
def add_token(self, obj):
self.tokens.append((self.tokenstart, obj))
return
def parse_comment(self, s, i):
m = EOL.search(s, i)
if not m:
self.token += s[i:]
return (self.parse_comment, len(s))
j = m.start(0)
self.token += s[i:j]
# We ignore comments.
#self.tokens.append(self.token)
return (self.parse_main, j)
def parse_literal(self, s, i):
m = END_LITERAL.search(s, i)
if not m:
self.token += s[i:]
return (self.parse_literal, len(s))
j = m.start(0)
self.token += s[i:j]
c = s[j]
if c == '#':
self.hex = ''
return (self.parse_literal_hex, j+1)
self.add_token(LIT(self.token))
return (self.parse_main, j)
def parse_literal_hex(self, s, i):
c = s[i]
if HEX.match(c) and len(self.hex) < 2:
self.hex += c
return (self.parse_literal_hex, i+1)
if self.hex:
self.token += chr(int(self.hex, 16))
return (self.parse_literal, i)
def parse_number(self, s, i):
m = END_NUMBER.search(s, i)
if not m:
self.token += s[i:]
return (self.parse_number, len(s))
j = m.start(0)
self.token += s[i:j]
c = s[j]
if c == '.':
self.token += c
return (self.parse_float, j+1)
try:
self.add_token(int(self.token))
except ValueError:
pass
return (self.parse_main, j)
def parse_float(self, s, i):
m = END_NUMBER.search(s, i)
if not m:
self.token += s[i:]
return (self.parse_float, len(s))
j = m.start(0)
self.token += s[i:j]
self.add_token(float(self.token))
return (self.parse_main, j)
def parse_keyword(self, s, i):
m = END_KEYWORD.search(s, i)
if not m:
self.token += s[i:]
return (self.parse_keyword, len(s))
j = m.start(0)
self.token += s[i:j]
if self.token == 'true':
token = True
elif self.token == 'false':
token = False
else:
token = KWD(self.token)
self.add_token(token)
return (self.parse_main, j)
def parse_string(self, s, i):
m = END_STRING.search(s, i)
if not m:
self.token += s[i:]
return (self.parse_string, len(s))
j = m.start(0)
self.token += s[i:j]
c = s[j]
if c == '\\':
self.oct = ''
return (self.parse_string_1, j+1)
if c == '(':
self.paren += 1
self.token += c
return (self.parse_string, j+1)
if c == ')':
self.paren -= 1
if self.paren:
self.token += c
return (self.parse_string, j+1)
self.add_token(self.token)
return (self.parse_main, j+1)
def parse_string_1(self, s, i):
c = s[i]
if OCT_STRING.match(c) and len(self.oct) < 3:
self.oct += c
return (self.parse_string_1, i+1)
if self.oct:
self.token += chr(int(self.oct, 8))
return (self.parse_string, i)
if c in ESC_STRING:
self.token += chr(ESC_STRING[c])
return (self.parse_string, i+1)
def parse_wopen(self, s, i):
c = s[i]
if c.isspace() or HEX.match(c):
return (self.parse_hexstring, i)
if c == '<':
self.add_token(KEYWORD_DICT_BEGIN)
i += 1
return (self.parse_main, i)
def parse_wclose(self, s, i):
c = s[i]
if c == '>':
self.add_token(KEYWORD_DICT_END)
i += 1
return (self.parse_main, i)
def parse_hexstring(self, s, i):
m = END_HEX_STRING.search(s, i)
if not m:
self.token += s[i:]
return (self.parse_hexstring, len(s))
j = m.start(0)
self.token += s[i:j]
token = HEX_PAIR.sub(lambda m: chr(int(m.group(0), 16)),
SPC.sub('', self.token))
self.add_token(token)
return (self.parse_main, j)
def nexttoken(self):
while not self.tokens:
self.fillbuf()
(self.parse1, self.charpos) = self.parse1(self.buf, self.charpos)
token = self.tokens.pop(0)
return token
def nextline(self):
'''
Fetches a next line that ends either with \\r or \\n.
'''
linebuf = ''
linepos = self.bufpos + self.charpos
eol = False
while 1:
self.fillbuf()
if eol:
c = self.buf[self.charpos]
# handle '\r\n'
if c == '\n':
linebuf += c
self.charpos += 1
break
m = EOL.search(self.buf, self.charpos)
if m:
linebuf += self.buf[self.charpos:m.end(0)]
self.charpos = m.end(0)
if linebuf[-1] == '\r':
eol = True
else:
break
else:
linebuf += self.buf[self.charpos:]
self.charpos = len(self.buf)
return (linepos, linebuf)
def revreadlines(self):
'''
Fetches a next line backword. This is used to locate
the trailers at the end of a file.
'''
self.fp.seek(0, 2)
pos = self.fp.tell()
buf = ''
while 0 < pos:
pos = max(0, pos-self.BUFSIZ)
self.fp.seek(pos)
s = self.fp.read(self.BUFSIZ)
if not s: break
while 1:
n = max(s.rfind('\r'), s.rfind('\n'))
if n == -1:
buf = s + buf
break
yield buf+s[n:]
s = s[:n]
buf = ''
return
## PSStackParser
##
class PSStackParser(PSBaseParser):
def __init__(self, fp):
PSBaseParser.__init__(self, fp)
self.reset()
return
def reset(self):
self.context = []
self.curtype = None
self.curstack = []
self.results = []
return
def seek(self, pos):
PSBaseParser.seek(self, pos)
self.reset()
return
def push(self, *objs):
self.curstack.extend(objs)
return
def pop(self, n):
objs = self.curstack[-n:]
self.curstack[-n:] = []
return objs
def popall(self):
objs = self.curstack
self.curstack = []
return objs
def add_results(self, *objs):
self.results.extend(objs)
return
def start_type(self, pos, type):
self.context.append((pos, self.curtype, self.curstack))
(self.curtype, self.curstack) = (type, [])
return
def end_type(self, type):
if self.curtype != type:
raise PSTypeError('Type mismatch: %r != %r' % (self.curtype, type))
objs = [ obj for (_,obj) in self.curstack ]
(pos, self.curtype, self.curstack) = self.context.pop()
return (pos, objs)
def do_keyword(self, pos, token):
return
def nextobject(self):
'''
Yields a list of objects: keywords, literals, strings,
numbers, arrays and dictionaries. Arrays and dictionaries
are represented as Python sequence and dictionaries.
'''
while not self.results:
(pos, token) = self.nexttoken()
#print (pos,token), (self.curtype, self.curstack)
if (isinstance(token, int) or
isinstance(token, float) or
isinstance(token, bool) or
isinstance(token, str) or
isinstance(token, PSLiteral)):
# normal token
self.push((pos, token))
elif token == KEYWORD_ARRAY_BEGIN:
# begin array
self.start_type(pos, 'a')
elif token == KEYWORD_ARRAY_END:
# end array
try:
self.push(self.end_type('a'))
except PSTypeError:
if STRICT: raise
elif token == KEYWORD_DICT_BEGIN:
# begin dictionary
self.start_type(pos, 'd')
elif token == KEYWORD_DICT_END:
# end dictionary
try:
(pos, objs) = self.end_type('d')
if len(objs) % 2 != 0:
raise PSSyntaxError(
'Invalid dictionary construct: %r' % objs)
d = dict((literal_name(k), v) \
for (k,v) in choplist(2, objs))
self.push((pos, d))
except PSTypeError:
if STRICT: raise
else:
self.do_keyword(pos, token)
if self.context:
continue
else:
self.flush()
obj = self.results.pop(0)
return obj
## PDF Objects
##
class PDFObject(PSObject): pass
class PDFException(PSException): pass
class PDFTypeError(PDFException): pass
class PDFValueError(PDFException): pass
class PDFNotImplementedError(PSException): pass
## PDFObjRef
##
class PDFObjRef(PDFObject):
def __init__(self, doc, objid, _):
if objid == 0:
if STRICT:
raise PDFValueError('PDF object id cannot be 0.')
self.doc = doc
self.objid = objid
#self.genno = genno # Never used.
return
def __repr__(self):
return '<PDFObjRef:%d>' % (self.objid)
def resolve(self):
return self.doc.getobj(self.objid)
# resolve
def resolve1(x):
'''
Resolve an object. If this is an array or dictionary,
it may still contains some indirect objects inside.
'''
while isinstance(x, PDFObjRef):
x = x.resolve()
return x
def resolve_all(x):
'''
Recursively resolve X and all the internals.
Make sure there is no indirect reference within the nested object.
This procedure might be slow.
'''
while isinstance(x, PDFObjRef):
x = x.resolve()
if isinstance(x, list):
x = [ resolve_all(v) for v in x ]
elif isinstance(x, dict):
for (k,v) in x.iteritems():
x[k] = resolve_all(v)
return x
def decipher_all(decipher, objid, genno, x):
'''
Recursively decipher X.
'''
if isinstance(x, str):
return decipher(objid, genno, x)
if isinstance(x, list):
x = [ decipher_all(decipher, objid, genno, v) for v in x ]
elif isinstance(x, dict):
for (k,v) in x.iteritems():
x[k] = decipher_all(decipher, objid, genno, v)
return x
# Type cheking
def int_value(x):
x = resolve1(x)
if not isinstance(x, int):
if STRICT:
raise PDFTypeError('Integer required: %r' % x)
return 0
return x
def float_value(x):
x = resolve1(x)
if not isinstance(x, float):
if STRICT:
raise PDFTypeError('Float required: %r' % x)
return 0.0
return x
def num_value(x):
x = resolve1(x)
if not (isinstance(x, int) or isinstance(x, float)):
if STRICT:
raise PDFTypeError('Int or Float required: %r' % x)
return 0
return x
def str_value(x):
x = resolve1(x)
if not isinstance(x, str):
if STRICT:
raise PDFTypeError('String required: %r' % x)
return ''
return x
def list_value(x):
x = resolve1(x)
if not (isinstance(x, list) or isinstance(x, tuple)):
if STRICT:
raise PDFTypeError('List required: %r' % x)
return []
return x
def dict_value(x):
x = resolve1(x)
if not isinstance(x, dict):
if STRICT:
raise PDFTypeError('Dict required: %r' % x)
return {}
return x
def stream_value(x):
x = resolve1(x)
if not isinstance(x, PDFStream):
if STRICT:
raise PDFTypeError('PDFStream required: %r' % x)
return PDFStream({}, '')
return x
## PDFStream type
##
class PDFStream(PDFObject):
def __init__(self, dic, rawdata, decipher=None):
length = int_value(dic.get('Length', 0))
eol = rawdata[length:]
if eol in ('\r', '\n', '\r\n'):
rawdata = rawdata[:length]
if length != len(rawdata):
print >>sys.stderr, "[warning] data length mismatch"
self.dic = dic
self.rawdata = rawdata
self.decipher = decipher
self.data = None
self.objid = None
self.genno = None
return
def set_objid(self, objid, genno):
self.objid = objid
self.genno = genno
return
def __repr__(self):
return '<PDFStream(%r): raw=%d, %r>' % \
(self.objid, len(self.rawdata), self.dic)
def get_rawdata(self):
return self.rawdata
def get_decdata(self):
data = self.rawdata
if self.decipher:
# Handle encryption
data = self.decipher(self.objid, self.genno, data)
return data
## PDF Exceptions
##
class PDFSyntaxError(PDFException): pass
class PDFNoValidXRef(PDFSyntaxError): pass
class PDFEncryptionError(PDFException): pass
class PDFPasswordIncorrect(PDFEncryptionError): pass
# some predefined literals and keywords.
LITERAL_OBJSTM = PSLiteralTable.intern('ObjStm')
LITERAL_XREF = PSLiteralTable.intern('XRef')
LITERAL_PAGE = PSLiteralTable.intern('Page')
LITERAL_PAGES = PSLiteralTable.intern('Pages')
LITERAL_CATALOG = PSLiteralTable.intern('Catalog')
## XRefs
##
## PDFXRef
##
class PDFXRef(object):
def __init__(self):
self.offsets = None
return
def __repr__(self):
return '<PDFXRef: objs=%d>' % len(self.offsets)
def objids(self):
return self.offsets.iterkeys()
def load(self, parser):
self.offsets = {}
while 1:
try:
(pos, line) = parser.nextline()
except PSEOF:
raise PDFNoValidXRef('Unexpected EOF - file corrupted?')
if not line:
raise PDFNoValidXRef('Premature eof: %r' % parser)
if line.startswith('trailer'):
parser.seek(pos)
break
f = line.strip().split(' ')
if len(f) != 2:
raise PDFNoValidXRef('Trailer not found: %r: line=%r' % (parser, line))
try:
(start, nobjs) = map(long, f)
except ValueError:
raise PDFNoValidXRef('Invalid line: %r: line=%r' % (parser, line))
for objid in xrange(start, start+nobjs):
try:
(_, line) = parser.nextline()
except PSEOF:
raise PDFNoValidXRef('Unexpected EOF - file corrupted?')
f = line.strip().split(' ')
if len(f) != 3:
raise PDFNoValidXRef('Invalid XRef format: %r, line=%r' % (parser, line))
(pos, genno, use) = f
if use != 'n': continue
self.offsets[objid] = (int(genno), long(pos))
self.load_trailer(parser)
return
KEYWORD_TRAILER = PSKeywordTable.intern('trailer')
def load_trailer(self, parser):
try:
(_,kwd) = parser.nexttoken()
assert kwd is self.KEYWORD_TRAILER
(_,dic) = parser.nextobject()
except PSEOF:
x = parser.pop(1)
if not x:
raise PDFNoValidXRef('Unexpected EOF - file corrupted')
(_,dic) = x[0]
self.trailer = dict_value(dic)
return
def getpos(self, objid):
try:
(genno, pos) = self.offsets[objid]
except KeyError:
raise
return (None, pos)
## PDFDocument
##
## A PDFDocument object represents a PDF document.
## Since a PDF file is usually pretty big, normally it is not loaded
## at once. Rather it is parsed dynamically as processing goes.
## A PDF parser is associated with the document.
##
class PDFDocument(object):
def __init__(self):
self.xrefs = []
self.objs = {}
self.parsed_objs = {}
self.root = None
self.catalog = None
self.parser = None
self.encryption = None
self.decipher = None
self.ready = False
return
# set_parser(parser)
# Associates the document with an (already initialized) parser object.
def set_parser(self, parser):
if self.parser: return
self.parser = parser
# The document is set to be temporarily ready during collecting
# all the basic information about the document, e.g.
# the header, the encryption information, and the access rights
# for the document.
self.ready = True
# Retrieve the information of each header that was appended
# (maybe multiple times) at the end of the document.
self.xrefs = parser.read_xref()
for xref in self.xrefs:
trailer = xref.trailer
if not trailer: continue
# If there's an encryption info, remember it.
if 'Encrypt' in trailer:
#assert not self.encryption
self.encryption = (list_value(trailer['ID']),
dict_value(trailer['Encrypt']))
if 'Root' in trailer:
self.set_root(dict_value(trailer['Root']))
break
else:
raise PDFSyntaxError('No /Root object! - Is this really a PDF?')
# The document is set to be non-ready again, until all the
# proper initialization (asking the password key and
# verifying the access permission, so on) is finished.
self.ready = False
return
# set_root(root)
# Set the Root dictionary of the document.
# Each PDF file must have exactly one /Root dictionary.
def set_root(self, root):
self.root = root
self.catalog = dict_value(self.root)
if self.catalog.get('Type') is not LITERAL_CATALOG:
if STRICT:
raise PDFSyntaxError('Catalog not found!')
return
# initialize(password='')
# Perform the initialization with a given password.
# This step is mandatory even if there's no password associated
# with the document.
def initialize(self, password=''):
if not self.encryption:
self.is_printable = self.is_modifiable = self.is_extractable = True
self.ready = True
return
(docid, param) = self.encryption
type = literal_name(param['Filter'])
if type == 'Standard':
return self.initialize_standard(password, docid, param)
if type == 'EBX_HANDLER':
return self.initialize_ebx(password, docid, param)
raise PDFEncryptionError('Unknown filter: param=%r' % param)
def initialize_ebx(self, password, docid, param):
self.is_printable = self.is_modifiable = self.is_extractable = True
with open(password, 'rb') as f:
keyder = f.read()
key = ASN1Parser([ord(x) for x in keyder])
key = [bytesToNumber(key.getChild(x).value) for x in xrange(1, 4)]
rsa = RSA.construct(key)
length = int_value(param.get('Length')) / 8
rights = str_value(param.get('ADEPT_LICENSE')).decode('base64')
rights = zlib.decompress(rights, -15)
rights = etree.fromstring(rights)
expr = './/{http://ns.adobe.com/adept}encryptedKey'
bookkey = ''.join(rights.findtext(expr)).decode('base64')
bookkey = rsa.decrypt(bookkey)
if bookkey[0] != '\x02':
raise ADEPTError('error decrypting book session key')
index = bookkey.index('\0') + 1
bookkey = bookkey[index:]
V = 2
if (length and len(bookkey) == (length + 1)) or \
(not length and len(bookkey) & 1 == 1):
V = ord(bookkey[0])
bookkey = bookkey[1:]
if length and len(bookkey) != length:
raise ADEPTError('error decrypting book session key')
self.decrypt_key = bookkey
self.genkey = self.genkey_v3 if V == 3 else self.genkey_v2
self.decipher = self.decrypt_rc4
self.ready = True
return
PASSWORD_PADDING = '(\xbfN^Nu\x8aAd\x00NV\xff\xfa\x01\x08..' \
'\x00\xb6\xd0h>\x80/\x0c\xa9\xfedSiz'
def initialize_standard(self, password, docid, param):
V = int_value(param.get('V', 0))
if not (V == 1 or V == 2):
raise PDFEncryptionError('Unknown algorithm: param=%r' % param)
length = int_value(param.get('Length', 40)) # Key length (bits)
O = str_value(param['O'])
R = int_value(param['R']) # Revision
if 5 <= R:
raise PDFEncryptionError('Unknown revision: %r' % R)
U = str_value(param['U'])
P = int_value(param['P'])
self.is_printable = bool(P & 4)
self.is_modifiable = bool(P & 8)
self.is_extractable = bool(P & 16)
# Algorithm 3.2
password = (password+self.PASSWORD_PADDING)[:32] # 1
hash = hashlib.md5(password) # 2
hash.update(O) # 3
hash.update(struct.pack('<l', P)) # 4
hash.update(docid[0]) # 5
if 4 <= R:
# 6
raise PDFNotImplementedError(
'Revision 4 encryption is currently unsupported')
if 3 <= R:
# 8
for _ in xrange(50):
hash = hashlib.md5(hash.digest()[:length/8])
key = hash.digest()[:length/8]
if R == 2:
# Algorithm 3.4
u1 = ARC4.new(key).decrypt(password)
elif R == 3:
# Algorithm 3.5
hash = hashlib.md5(self.PASSWORD_PADDING) # 2
hash.update(docid[0]) # 3
x = ARC4.new(key).decrypt(hash.digest()[:16]) # 4
for i in xrange(1,19+1):
k = ''.join( chr(ord(c) ^ i) for c in key )
x = ARC4.new(k).decrypt(x)
u1 = x+x # 32bytes total
if R == 2:
is_authenticated = (u1 == U)
else:
is_authenticated = (u1[:16] == U[:16])
if not is_authenticated:
raise PDFPasswordIncorrect
self.decrypt_key = key
self.genkey = self.genkey_v2
self.decipher = self.decipher_rc4 # XXX may be AES
self.ready = True
return
def genkey_v2(self, objid, genno):
objid = struct.pack('<L', objid)[:3]
genno = struct.pack('<L', genno)[:2]
key = self.decrypt_key + objid + genno
hash = hashlib.md5(key)
key = hash.digest()[:min(len(self.decrypt_key) + 5, 16)]
return key
def genkey_v3(self, objid, genno):
objid = struct.pack('<L', objid ^ 0x3569ac)
genno = struct.pack('<L', genno ^ 0xca96)
key = self.decrypt_key
key += objid[0] + genno[0] + objid[1] + genno[1] + objid[2] + 'sAlT'
hash = hashlib.md5(key)
key = hash.digest()[:min(len(self.decrypt_key) + 5, 16)]
return key
def decrypt_rc4(self, objid, genno, data):
key = self.genkey(objid, genno)
return ARC4.new(key).decrypt(data)
KEYWORD_OBJ = PSKeywordTable.intern('obj')
def getobj(self, objid):
if not self.ready:
raise PDFException('PDFDocument not initialized')
#assert self.xrefs
if objid in self.objs:
genno = 0
obj = self.objs[objid]
else:
for xref in self.xrefs:
try:
(strmid, index) = xref.getpos(objid)
break
except KeyError:
pass
else:
if STRICT:
raise PDFSyntaxError('Cannot locate objid=%r' % objid)
return None
if strmid:
stream = stream_value(self.getobj(strmid))
if stream.dic.get('Type') is not LITERAL_OBJSTM:
if STRICT:
raise PDFSyntaxError('Not a stream object: %r' % stream)
try:
n = stream.dic['N']
except KeyError:
if STRICT:
raise PDFSyntaxError('N is not defined: %r' % stream)
n = 0
if strmid in self.parsed_objs:
objs = self.parsed_objs[strmid]
else:
parser = PDFObjStrmParser(self, stream.get_data())
objs = []
try:
while 1:
(_,obj) = parser.nextobject()
objs.append(obj)
except PSEOF:
pass
self.parsed_objs[strmid] = objs
genno = 0
i = n*2+index
try:
obj = objs[i]
except IndexError:
raise PDFSyntaxError(
'Invalid object number: objid=%r' % (objid))
if isinstance(obj, PDFStream):
obj.set_objid(objid, 0)
else:
self.parser.seek(index)
(_,objid1) = self.parser.nexttoken() # objid
(_,genno) = self.parser.nexttoken() # genno
#assert objid1 == objid, (objid, objid1)
(_,kwd) = self.parser.nexttoken()
if kwd is not self.KEYWORD_OBJ:
raise PDFSyntaxError(
'Invalid object spec: offset=%r' % index)
(_,obj) = self.parser.nextobject()
if isinstance(obj, PDFStream):
obj.set_objid(objid, genno)
self.objs[objid] = obj
if self.decipher:
obj = decipher_all(self.decipher, objid, genno, obj)
return obj
## PDFParser
##
class PDFParser(PSStackParser):
def __init__(self, doc, fp):
PSStackParser.__init__(self, fp)
self.doc = doc
self.doc.set_parser(self)
return
def __repr__(self):
return '<PDFParser>'
KEYWORD_R = PSKeywordTable.intern('R')
KEYWORD_ENDOBJ = PSKeywordTable.intern('endobj')
KEYWORD_STREAM = PSKeywordTable.intern('stream')
KEYWORD_XREF = PSKeywordTable.intern('xref')
KEYWORD_STARTXREF = PSKeywordTable.intern('startxref')
def do_keyword(self, pos, token):
if token in (self.KEYWORD_XREF, self.KEYWORD_STARTXREF):
self.add_results(*self.pop(1))
return
if token is self.KEYWORD_ENDOBJ:
self.add_results(*self.pop(4))
return
if token is self.KEYWORD_R:
# reference to indirect object
try:
((_,objid), (_,genno)) = self.pop(2)
(objid, genno) = (int(objid), int(genno))
obj = PDFObjRef(self.doc, objid, genno)
self.push((pos, obj))
except PSSyntaxError:
pass
return
if token is self.KEYWORD_STREAM:
# stream object
((_,dic),) = self.pop(1)
dic = dict_value(dic)
try:
objlen = int_value(dic['Length'])
except KeyError:
if STRICT:
raise PDFSyntaxError('/Length is undefined: %r' % dic)
objlen = 0
self.seek(pos)
try:
(_, line) = self.nextline() # 'stream'
except PSEOF:
if STRICT:
raise PDFSyntaxError('Unexpected EOF')
return
pos += len(line)
self.fp.seek(pos)
data = self.fp.read(objlen)
self.seek(pos+objlen)
while 1:
try:
(linepos, line) = self.nextline()
except PSEOF:
if STRICT:
raise PDFSyntaxError('Unexpected EOF')
break
if 'endstream' in line:
i = line.index('endstream')
objlen += i
data += line[:i]
break
objlen += len(line)
data += line
self.seek(pos+objlen)
obj = PDFStream(dic, data, self.doc.decipher)
self.push((pos, obj))
return
# others
self.push((pos, token))
return
def find_xref(self):
# search the last xref table by scanning the file backwards.
prev = None
for line in self.revreadlines():
line = line.strip()
if line == 'startxref': break
if line:
prev = line
else:
raise PDFNoValidXRef('Unexpected EOF')
return long(prev)
# read xref table
def read_xref_from(self, start, xrefs):
self.seek(start)
self.reset()
try:
(pos, token) = self.nexttoken()
except PSEOF:
raise PDFNoValidXRef('Unexpected EOF')
if token is not self.KEYWORD_XREF:
raise PDFNoValidXRef('xref not found: pos=%d, token=%r' %
(pos, token))
self.nextline()
xref = PDFXRef()
xref.load(self)
xrefs.append(xref)
trailer = xref.trailer
if 'Prev' in trailer:
# find previous xref
pos = int_value(trailer['Prev'])
self.read_xref_from(pos, xrefs)
return
# read xref tables and trailers
def read_xref(self):
xrefs = []
try:
pos = self.find_xref()
self.read_xref_from(pos, xrefs)
except PDFNoValidXRef:
# fallback
self.seek(0)
pat = re.compile(r'^(\d+)\s+(\d+)\s+obj\b')
offsets = {}
xref = PDFXRef()
while 1:
try:
(pos, line) = self.nextline()
except PSEOF:
break
if line.startswith('trailer'): break
m = pat.match(line)
if not m: continue
(objid, genno) = m.groups()
offsets[int(objid)] = (0, pos)
if not offsets: raise
xref.offsets = offsets
self.seek(pos)
xref.load_trailer(self)
xrefs.append(xref)
return xrefs
###
### My own code, for which there is none else to blame
class PDFSerializer(object):
def __init__(self, inf, keypath):
self.version = inf.read(8)
inf.seek(0)
self.doc = doc = PDFDocument()
parser = PDFParser(doc, inf)
doc.initialize(keypath)
self.objids = objids = set()
for xref in doc.xrefs:
trailer = xref.trailer
for objid in xref.objids():
objids.add(objid)
if 'Encrypt' in trailer:
objids.remove(trailer.pop('Encrypt').objid)
self.trailer = trailer
def dump(self, outf):
self.outf = outf
self.write(self.version)
self.write('\n%\xe2\xe3\xcf\xd3\n')
doc = self.doc
objids = self.objids
xrefs = {}
maxobj = max(objids)
for objid in objids:
xrefs[objid] = self.tell()
self.serialize_indirect(objid, doc.getobj(objid))
startxref = self.tell()
self.write('xref\n')
self.write('0 %d\n' % (maxobj + 1,))
for objid in xrange(0, maxobj + 1):
if objid in objids:
self.write("%010d %05d n \n" % (xrefs[objid], 0))
else:
self.write("%010d %05d f \n" % (0, 65535))
self.write('trailer\n')
self.serialize_object(self.trailer)
self.write('\nstartxref\n%d\n%%%%EOF' % startxref)
def write(self, *data):
for datum in data:
self.outf.write(datum)
self.last = data[-1][-1:]
def tell(self):
return self.outf.tell()
def escape_string(self, string):
string = string.replace('\\', '\\\\')
string = string.replace('\n', r'\n')
string = string.replace('(', r'\(')
string = string.replace(')', r'\)')
return string
def serialize_object(self, obj):
if isinstance(obj, dict):
self.write('<<')
for key, val in obj.items():
self.write('/%s' % key)
self.serialize_object(val)
self.write('>>')
elif isinstance(obj, list):
self.write('[')
for val in obj:
self.serialize_object(val)
self.write(']')
elif isinstance(obj, str):
self.write('(%s)' % self.escape_string(obj))
elif isinstance(obj, bool):
if self.last.isalnum():
self.write(' ')
self.write(str(obj).lower())
elif isinstance(obj, (int, long, float)):
if self.last.isalnum():
self.write(' ')
self.write(str(obj))
elif isinstance(obj, PDFObjRef):
if self.last.isalnum():
self.write(' ')
self.write('%d %d R' % (obj.objid, 0))
elif isinstance(obj, PDFStream):
data = obj.get_decdata()
self.serialize_object(obj.dic)
self.write('stream\n')
self.write(data)
self.write('\nendstream')
else:
data = str(obj)
if data[0].isalnum() and self.last.isalnum():
self.write(' ')
self.write(data)
def serialize_indirect(self, objid, obj):
self.write('%d 0 obj' % (objid,))
self.serialize_object(obj)
if self.last.isalnum():
self.write('\n')
self.write('endobj\n')
def cli_main(argv=sys.argv):
progname = os.path.basename(argv[0])
if RSA is None:
print "%s: This script requires PyCrypto, which must be installed " \
"separately. Read the top-of-script comment for details." % \
(progname,)
return 1
if len(argv) != 4:
print "usage: %s KEYFILE INBOOK OUTBOOK" % (progname,)
return 1
keypath, inpath, outpath = argv[1:]
with open(inpath, 'rb') as inf:
serializer = PDFSerializer(inf, keypath)
with open(outpath, 'wb') as outf:
serializer.dump(outf)
return 0
class DecryptionDialog(Tkinter.Frame):
def __init__(self, root):
Tkinter.Frame.__init__(self, root, border=5)
self.status = Tkinter.Label(self, text='Select files for decryption')
self.status.pack(fill=Tkconstants.X, expand=1)
body = Tkinter.Frame(self)
body.pack(fill=Tkconstants.X, expand=1)
sticky = Tkconstants.E + Tkconstants.W
body.grid_columnconfigure(1, weight=2)
Tkinter.Label(body, text='Key file').grid(row=0)
self.keypath = Tkinter.Entry(body, width=30)
self.keypath.grid(row=0, column=1, sticky=sticky)
if os.path.exists('adeptkey.der'):
self.keypath.insert(0, 'adeptkey.der')
button = Tkinter.Button(body, text="...", command=self.get_keypath)
button.grid(row=0, column=2)
Tkinter.Label(body, text='Input file').grid(row=1)
self.inpath = Tkinter.Entry(body, width=30)
self.inpath.grid(row=1, column=1, sticky=sticky)
button = Tkinter.Button(body, text="...", command=self.get_inpath)
button.grid(row=1, column=2)
Tkinter.Label(body, text='Output file').grid(row=2)
self.outpath = Tkinter.Entry(body, width=30)
self.outpath.grid(row=2, column=1, sticky=sticky)
button = Tkinter.Button(body, text="...", command=self.get_outpath)
button.grid(row=2, column=2)
buttons = Tkinter.Frame(self)
buttons.pack()
botton = Tkinter.Button(
buttons, text="Decrypt", width=10, command=self.decrypt)
botton.pack(side=Tkconstants.LEFT)
Tkinter.Frame(buttons, width=10).pack(side=Tkconstants.LEFT)
button = Tkinter.Button(
buttons, text="Quit", width=10, command=self.quit)
button.pack(side=Tkconstants.RIGHT)
def get_keypath(self):
keypath = tkFileDialog.askopenfilename(
parent=None, title='Select ADEPT key file',
defaultextension='.der', filetypes=[('DER-encoded files', '.der'),
('All Files', '.*')])
if keypath:
keypath = os.path.normpath(keypath)
self.keypath.delete(0, Tkconstants.END)
self.keypath.insert(0, keypath)
return
def get_inpath(self):
inpath = tkFileDialog.askopenfilename(
parent=None, title='Select ADEPT-encrypted PDF file to decrypt',
defaultextension='.epub', filetypes=[('PDF files', '.pdf'),
('All files', '.*')])
if inpath:
inpath = os.path.normpath(inpath)
self.inpath.delete(0, Tkconstants.END)
self.inpath.insert(0, inpath)
return
def get_outpath(self):
outpath = tkFileDialog.asksaveasfilename(
parent=None, title='Select unencrypted PDF file to produce',
defaultextension='.epub', filetypes=[('PDF files', '.pdf'),
('All files', '.*')])
if outpath:
outpath = os.path.normpath(outpath)
self.outpath.delete(0, Tkconstants.END)
self.outpath.insert(0, outpath)
return
def decrypt(self):
keypath = self.keypath.get()
inpath = self.inpath.get()
outpath = self.outpath.get()
if not keypath or not os.path.exists(keypath):
self.status['text'] = 'Specified key file does not exist'
return
if not inpath or not os.path.exists(inpath):
self.status['text'] = 'Specified input file does not exist'
return
if not outpath:
self.status['text'] = 'Output file not specified'
return
if inpath == outpath:
self.status['text'] = 'Must have different input and output files'
return
argv = [sys.argv[0], keypath, inpath, outpath]
self.status['text'] = 'Decrypting...'
try:
cli_main(argv)
except Exception, e:
self.status['text'] = 'Error: ' + str(e)
return
self.status['text'] = 'File successfully decrypted'
def gui_main():
root = Tkinter.Tk()
if RSA is None:
root.withdraw()
tkMessageBox.showerror(
"INEPT PDF Decrypter",
"This script requires PyCrypto, which must be installed "
"separately. Read the top-of-script comment for details.")
return 1
root.title('INEPT PDF Decrypter')
root.resizable(True, False)
root.minsize(300, 0)
DecryptionDialog(root).pack(fill=Tkconstants.X, expand=1)
root.mainloop()
return 0
if __name__ == '__main__':
# sys.exit(cli_main())
sys.exit(gui_main())