2309 lines
75 KiB
Python
2309 lines
75 KiB
Python
#!/usr/bin/env python3
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# -*- coding: utf-8 -*-
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# ineptpdf.py
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# Copyright © 2009-2020 by i♥cabbages, Apprentice Harper et al.
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# Copyright © 2021-2022 by noDRM et al.
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# Released under the terms of the GNU General Public Licence, version 3
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# <http://www.gnu.org/licenses/>
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"""
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Decrypts Adobe ADEPT-encrypted PDF files.
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"""
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from decrypt.params import KEYPATH
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__license__ = 'GPL v3'
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__version__ = "10.0.4"
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import codecs
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import hashlib
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import sys
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import os
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import re
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import zlib
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import struct
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import binascii
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import base64
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from io import BytesIO
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from decimal import Decimal
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import itertools
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import xml.etree.ElementTree as etree
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import traceback
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from uuid import UUID
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try:
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from Cryptodome.Cipher import AES, ARC4, PKCS1_v1_5
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from Cryptodome.PublicKey import RSA
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except ImportError:
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from Crypto.Cipher import AES, ARC4, PKCS1_v1_5
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from Crypto.PublicKey import RSA
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def unpad(data, padding=16):
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if sys.version_info[0] == 2:
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pad_len = ord(data[-1])
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else:
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pad_len = data[-1]
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return data[:-pad_len]
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iswindows = sys.platform.startswith('win')
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isosx = sys.platform.startswith('darwin')
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class ADEPTError(Exception):
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pass
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class ADEPTInvalidPasswordError(Exception):
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pass
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class ADEPTNewVersionError(Exception):
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pass
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def SHA256(message):
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return hashlib.sha256(message).digest()
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# Do we generate cross reference streams on output?
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# 0 = never
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# 1 = only if present in input
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# 2 = always
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GEN_XREF_STM = 1
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# This is the value for the current document
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gen_xref_stm = False # will be set in PDFSerializer
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# PDF parsing routines from pdfminer, with changes for EBX_HANDLER
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# Utilities
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def choplist(n, seq):
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'''Groups every n elements of the list.'''
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r = []
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for x in seq:
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r.append(x)
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if len(r) == n:
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yield tuple(r)
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r = []
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return
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def nunpack(s, default=0):
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'''Unpacks up to 4 bytes big endian.'''
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l = len(s)
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if not l:
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return default
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elif l == 1:
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return ord(s)
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elif l == 2:
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return struct.unpack('>H', s)[0]
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elif l == 3:
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if sys.version_info[0] == 2:
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return struct.unpack('>L', '\x00'+s)[0]
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else:
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return struct.unpack('>L', bytes([0]) + s)[0]
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elif l == 4:
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return struct.unpack('>L', s)[0]
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else:
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return TypeError('invalid length: %d' % l)
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STRICT = 0
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# PS Exceptions
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class PSException(Exception): pass
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class PSEOF(PSException): pass
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class PSSyntaxError(PSException): pass
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class PSTypeError(PSException): pass
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class PSValueError(PSException): pass
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# Basic PostScript Types
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# PSLiteral
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class PSObject(object): pass
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class PSLiteral(PSObject):
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'''
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PS literals (e.g. "/Name").
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Caution: Never create these objects directly.
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Use PSLiteralTable.intern() instead.
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'''
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def __init__(self, name):
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self.name = name.decode('utf-8')
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return
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def __repr__(self):
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name = []
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for char in self.name:
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if not char.isalnum():
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char = '#%02x' % ord(char)
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name.append(char)
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return '/%s' % ''.join(name)
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# PSKeyword
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class PSKeyword(PSObject):
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'''
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PS keywords (e.g. "showpage").
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Caution: Never create these objects directly.
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Use PSKeywordTable.intern() instead.
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'''
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def __init__(self, name):
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self.name = name.decode('utf-8')
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return
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def __repr__(self):
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return self.name
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# PSSymbolTable
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class PSSymbolTable(object):
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'''
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Symbol table that stores PSLiteral or PSKeyword.
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'''
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def __init__(self, classe):
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self.dic = {}
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self.classe = classe
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return
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def intern(self, name):
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if name in self.dic:
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lit = self.dic[name]
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else:
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lit = self.classe(name)
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self.dic[name] = lit
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return lit
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PSLiteralTable = PSSymbolTable(PSLiteral)
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PSKeywordTable = PSSymbolTable(PSKeyword)
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LIT = PSLiteralTable.intern
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KWD = PSKeywordTable.intern
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KEYWORD_BRACE_BEGIN = KWD(b'{')
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KEYWORD_BRACE_END = KWD(b'}')
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KEYWORD_ARRAY_BEGIN = KWD(b'[')
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KEYWORD_ARRAY_END = KWD(b']')
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KEYWORD_DICT_BEGIN = KWD(b'<<')
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KEYWORD_DICT_END = KWD(b'>>')
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def literal_name(x):
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if not isinstance(x, PSLiteral):
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if STRICT:
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raise PSTypeError('Literal required: %r' % x)
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else:
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return str(x)
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return x.name
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def keyword_name(x):
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if not isinstance(x, PSKeyword):
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if STRICT:
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raise PSTypeError('Keyword required: %r' % x)
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else:
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return str(x)
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return x.name
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## PSBaseParser
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##
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EOL = re.compile(br'[\r\n]')
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SPC = re.compile(br'\s')
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NONSPC = re.compile(br'\S')
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HEX = re.compile(br'[0-9a-fA-F]')
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END_LITERAL = re.compile(br'[#/%\[\]()<>{}\s]')
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END_HEX_STRING = re.compile(br'[^\s0-9a-fA-F]')
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HEX_PAIR = re.compile(br'[0-9a-fA-F]{2}|.')
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END_NUMBER = re.compile(br'[^0-9]')
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END_KEYWORD = re.compile(br'[#/%\[\]()<>{}\s]')
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END_STRING = re.compile(br'[()\\]')
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OCT_STRING = re.compile(br'[0-7]')
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ESC_STRING = { b'b':8, b't':9, b'n':10, b'f':12, b'r':13, b'(':40, b')':41, b'\\':92 }
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class EmptyArrayValue(object):
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def __str__(self):
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return "<>"
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class PSBaseParser(object):
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'''
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Most basic PostScript parser that performs only basic tokenization.
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'''
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BUFSIZ = 4096
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def __init__(self, fp):
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self.fp = fp
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self.seek(0)
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return
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def __repr__(self):
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return '<PSBaseParser: %r, bufpos=%d>' % (self.fp, self.bufpos)
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def flush(self):
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return
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def close(self):
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self.flush()
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return
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def tell(self):
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return self.bufpos+self.charpos
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def poll(self, pos=None, n=80):
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pos0 = self.fp.tell()
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if not pos:
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pos = self.bufpos+self.charpos
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self.fp.seek(pos)
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self.fp.seek(pos0)
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return
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def seek(self, pos):
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'''
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Seeks the parser to the given position.
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'''
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self.fp.seek(pos)
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# reset the status for nextline()
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self.bufpos = pos
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self.buf = b''
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self.charpos = 0
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# reset the status for nexttoken()
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self.parse1 = self.parse_main
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self.tokens = []
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return
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def fillbuf(self):
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if self.charpos < len(self.buf): return
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# fetch next chunk.
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self.bufpos = self.fp.tell()
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self.buf = self.fp.read(self.BUFSIZ)
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if not self.buf:
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raise PSEOF('Unexpected EOF')
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self.charpos = 0
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return
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def parse_main(self, s, i):
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m = NONSPC.search(s, i)
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if not m:
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return (self.parse_main, len(s))
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j = m.start(0)
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if isinstance(s[j], str):
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# Python 2
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c = s[j]
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else:
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# Python 3
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c = bytes([s[j]])
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self.tokenstart = self.bufpos+j
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if c == b'%':
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self.token = c
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return (self.parse_comment, j+1)
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if c == b'/':
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self.token = b''
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return (self.parse_literal, j+1)
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if c in b'-+' or c.isdigit():
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self.token = c
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return (self.parse_number, j+1)
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if c == b'.':
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self.token = c
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return (self.parse_decimal, j+1)
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if c.isalpha():
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self.token = c
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return (self.parse_keyword, j+1)
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if c == b'(':
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self.token = b''
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self.paren = 1
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return (self.parse_string, j+1)
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if c == b'<':
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self.token = b''
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return (self.parse_wopen, j+1)
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if c == b'>':
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self.token = b''
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return (self.parse_wclose, j+1)
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self.add_token(KWD(c))
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return (self.parse_main, j+1)
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def add_token(self, obj):
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self.tokens.append((self.tokenstart, obj))
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return
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def parse_comment(self, s, i):
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m = EOL.search(s, i)
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if not m:
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self.token += s[i:]
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return (self.parse_comment, len(s))
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j = m.start(0)
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self.token += s[i:j]
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# We ignore comments.
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#self.tokens.append(self.token)
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return (self.parse_main, j)
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def parse_literal(self, s, i):
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m = END_LITERAL.search(s, i)
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if not m:
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self.token += s[i:]
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return (self.parse_literal, len(s))
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j = m.start(0)
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self.token += s[i:j]
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if isinstance(s[j], str):
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c = s[j]
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else:
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c = bytes([s[j]])
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if c == b'#':
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self.hex = b''
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return (self.parse_literal_hex, j+1)
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self.add_token(LIT(self.token))
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return (self.parse_main, j)
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def parse_literal_hex(self, s, i):
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if isinstance(s[i], str):
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c = s[i]
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else:
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c = bytes([s[i]])
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if HEX.match(c) and len(self.hex) < 2:
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self.hex += c
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return (self.parse_literal_hex, i+1)
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if self.hex:
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if sys.version_info[0] == 2:
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self.token += chr(int(self.hex, 16))
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else:
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self.token += bytes([int(self.hex, 16)])
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return (self.parse_literal, i)
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def parse_number(self, s, i):
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m = END_NUMBER.search(s, i)
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if not m:
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self.token += s[i:]
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return (self.parse_number, len(s))
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j = m.start(0)
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self.token += s[i:j]
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if isinstance(s[j], str):
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c = s[j]
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else:
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c = bytes([s[j]])
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if c == b'.':
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self.token += c
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return (self.parse_decimal, j+1)
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try:
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self.add_token(int(self.token))
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except ValueError:
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pass
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return (self.parse_main, j)
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def parse_decimal(self, s, i):
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m = END_NUMBER.search(s, i)
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if not m:
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self.token += s[i:]
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return (self.parse_decimal, len(s))
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j = m.start(0)
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self.token += s[i:j]
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self.add_token(Decimal(self.token.decode('utf-8')))
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return (self.parse_main, j)
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def parse_keyword(self, s, i):
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m = END_KEYWORD.search(s, i)
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if not m:
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self.token += s[i:]
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return (self.parse_keyword, len(s))
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j = m.start(0)
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self.token += s[i:j]
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if self.token == 'true':
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token = True
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elif self.token == 'false':
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token = False
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else:
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token = KWD(self.token)
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self.add_token(token)
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return (self.parse_main, j)
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def parse_string(self, s, i):
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m = END_STRING.search(s, i)
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if not m:
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self.token += s[i:]
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return (self.parse_string, len(s))
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j = m.start(0)
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self.token += s[i:j]
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if isinstance(s[j], str):
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c = s[j]
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else:
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c = bytes([s[j]])
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if c == b'\\':
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self.oct = ''
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return (self.parse_string_1, j+1)
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if c == b'(':
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self.paren += 1
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self.token += c
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return (self.parse_string, j+1)
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if c == b')':
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self.paren -= 1
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if self.paren:
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self.token += c
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return (self.parse_string, j+1)
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self.add_token(self.token)
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return (self.parse_main, j+1)
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def parse_string_1(self, s, i):
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if isinstance(s[i], str):
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c = s[i]
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else:
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c = bytes([s[i]])
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if OCT_STRING.match(c) and len(self.oct) < 3:
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self.oct += c
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return (self.parse_string_1, i+1)
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if self.oct:
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if sys.version_info[0] == 2:
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self.token += chr(int(self.oct, 8))
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else:
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self.token += bytes([int(self.oct, 8)])
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return (self.parse_string, i)
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if c in ESC_STRING:
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if sys.version_info[0] == 2:
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self.token += chr(ESC_STRING[c])
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else:
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self.token += bytes([ESC_STRING[c]])
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return (self.parse_string, i+1)
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def parse_wopen(self, s, i):
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if isinstance(s[i], str):
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c = s[i]
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else:
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c = bytes([s[i]])
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if c.isspace() or HEX.match(c):
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return (self.parse_hexstring, i)
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if c == b'<':
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self.add_token(KEYWORD_DICT_BEGIN)
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i += 1
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if c == b'>':
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# Empty array without any contents. Why though?
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# We need to add some dummy python object that will serialize to
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# nothing, otherwise the code removes the whole array.
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self.add_token(EmptyArrayValue())
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i += 1
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return (self.parse_main, i)
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def parse_wclose(self, s, i):
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if isinstance(s[i], str):
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c = s[i]
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else:
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c = bytes([s[i]])
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if c == b'>':
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self.add_token(KEYWORD_DICT_END)
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i += 1
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return (self.parse_main, i)
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def parse_hexstring(self, s, i):
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m = END_HEX_STRING.search(s, i)
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if not m:
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self.token += s[i:]
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return (self.parse_hexstring, len(s))
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j = m.start(0)
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self.token += s[i:j]
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|
if sys.version_info[0] == 2:
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token = HEX_PAIR.sub(lambda m: chr(int(m.group(0), 16)),
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SPC.sub('', self.token))
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else:
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token = HEX_PAIR.sub(lambda m: bytes([int(m.group(0), 16)]),
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SPC.sub(b'', self.token))
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self.add_token(token)
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return (self.parse_main, j)
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|
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def nexttoken(self):
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while not self.tokens:
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self.fillbuf()
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(self.parse1, self.charpos) = self.parse1(self.buf, self.charpos)
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token = self.tokens.pop(0)
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return token
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|
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def nextline(self):
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'''
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|
Fetches a next line that ends either with \\r or \\n.
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|
'''
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|
linebuf = b''
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linepos = self.bufpos + self.charpos
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eol = False
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while 1:
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self.fillbuf()
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if eol:
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|
if sys.version_info[0] == 2:
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c = self.buf[self.charpos]
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else:
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c = bytes([self.buf[self.charpos]])
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|
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# handle '\r\n'
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if c == b'\n':
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linebuf += c
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self.charpos += 1
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break
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m = EOL.search(self.buf, self.charpos)
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if m:
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linebuf += self.buf[self.charpos:m.end(0)]
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self.charpos = m.end(0)
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|
if sys.version_info[0] == 2:
|
|
if linebuf[-1] == b'\r':
|
|
eol = True
|
|
else:
|
|
break
|
|
else:
|
|
if bytes([linebuf[-1]]) == b'\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 = b''
|
|
while 0 < pos:
|
|
prevpos = pos
|
|
pos = max(0, pos-self.BUFSIZ)
|
|
self.fp.seek(pos)
|
|
s = self.fp.read(prevpos-pos)
|
|
if not s: break
|
|
while 1:
|
|
n = max(s.rfind(b'\r'), s.rfind(b'\n'))
|
|
if n == -1:
|
|
buf = s + buf
|
|
break
|
|
yield s[n:]+buf
|
|
s = s[:n]
|
|
buf = b''
|
|
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, direct=False):
|
|
'''
|
|
Yields a list of objects: keywords, literals, strings (byte arrays),
|
|
numbers, arrays and dictionaries. Arrays and dictionaries
|
|
are represented as Python sequence and dictionaries.
|
|
'''
|
|
while not self.results:
|
|
(pos, token) = self.nexttoken()
|
|
if (isinstance(token, int) or
|
|
isinstance(token, Decimal) or
|
|
isinstance(token, bool) or
|
|
isinstance(token, bytearray) or
|
|
isinstance(token, bytes) 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:
|
|
print("Incomplete dictionary construct")
|
|
objs.append("") # this isn't necessary.
|
|
# temporary fix. is this due to rental books?
|
|
# 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:
|
|
if direct:
|
|
return self.pop(1)[0]
|
|
self.flush()
|
|
obj = self.results.pop(0)
|
|
return obj
|
|
|
|
|
|
LITERAL_CRYPT = LIT(b'Crypt')
|
|
LITERALS_FLATE_DECODE = (LIT(b'FlateDecode'), LIT(b'Fl'))
|
|
LITERALS_LZW_DECODE = (LIT(b'LZWDecode'), LIT(b'LZW'))
|
|
LITERALS_ASCII85_DECODE = (LIT(b'ASCII85Decode'), LIT(b'A85'))
|
|
|
|
|
|
## 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, genno):
|
|
if objid == 0:
|
|
if STRICT:
|
|
raise PDFValueError('PDF object id cannot be 0.')
|
|
self.doc = doc
|
|
self.objid = objid
|
|
self.genno = genno
|
|
return
|
|
|
|
def __repr__(self):
|
|
return '<PDFObjRef:%d %d>' % (self.objid, self.genno)
|
|
|
|
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 iter(x.items()):
|
|
x[k] = resolve_all(v)
|
|
return x
|
|
|
|
def decipher_all(decipher, objid, genno, x):
|
|
'''
|
|
Recursively decipher X.
|
|
'''
|
|
if isinstance(x, bytearray) or isinstance(x,bytes) or isinstance(x,str):
|
|
return decipher(objid, genno, x)
|
|
decf = lambda v: decipher_all(decipher, objid, genno, v)
|
|
if isinstance(x, list):
|
|
x = [decf(v) for v in x]
|
|
elif isinstance(x, dict):
|
|
x = dict((k, decf(v)) for (k, v) in iter(x.items()))
|
|
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 decimal_value(x):
|
|
x = resolve1(x)
|
|
if not isinstance(x, Decimal):
|
|
if STRICT:
|
|
raise PDFTypeError('Decimal required: %r' % x)
|
|
return 0.0
|
|
return x
|
|
|
|
def num_value(x):
|
|
x = resolve1(x)
|
|
if not (isinstance(x, int) or isinstance(x, Decimal)):
|
|
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, bytearray) or isinstance(x, bytes) or 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
|
|
|
|
# ascii85decode(data)
|
|
def ascii85decode(data):
|
|
n = b = 0
|
|
out = b''
|
|
for c in data:
|
|
if b'!' <= c and c <= b'u':
|
|
n += 1
|
|
b = b*85+(c-33)
|
|
if n == 5:
|
|
out += struct.pack('>L',b)
|
|
n = b = 0
|
|
elif c == b'z':
|
|
assert n == 0
|
|
out += b'\0\0\0\0'
|
|
elif c == b'~':
|
|
if n:
|
|
for _ in range(5-n):
|
|
b = b*85+84
|
|
out += struct.pack('>L',b)[:n-1]
|
|
break
|
|
return out
|
|
|
|
|
|
## PDFStream type
|
|
class PDFStream(PDFObject):
|
|
def __init__(self, dic, rawdata, decipher=None):
|
|
length = int_value(dic.get('Length', 0))
|
|
eol = rawdata[length:]
|
|
# quick and dirty fix for false length attribute,
|
|
# might not work if the pdf stream parser has a problem
|
|
if decipher != None and decipher.__name__ == 'decrypt_aes':
|
|
if (len(rawdata) % 16) != 0:
|
|
cutdiv = len(rawdata) // 16
|
|
rawdata = rawdata[:16*cutdiv]
|
|
else:
|
|
if eol in (b'\r', b'\n', b'\r\n'):
|
|
rawdata = rawdata[:length]
|
|
|
|
self.dic = dic
|
|
self.rawdata = rawdata
|
|
self.decipher = decipher
|
|
self.data = None
|
|
self.decdata = None
|
|
self.objid = None
|
|
self.genno = None
|
|
return
|
|
|
|
def set_objid(self, objid, genno):
|
|
self.objid = objid
|
|
self.genno = genno
|
|
return
|
|
|
|
def __repr__(self):
|
|
if self.rawdata:
|
|
return '<PDFStream(%r): raw=%d, %r>' % \
|
|
(self.objid, len(self.rawdata), self.dic)
|
|
else:
|
|
return '<PDFStream(%r): data=%d, %r>' % \
|
|
(self.objid, len(self.data), self.dic)
|
|
|
|
def decode(self):
|
|
assert self.data is None and self.rawdata is not None
|
|
data = self.rawdata
|
|
if self.decipher:
|
|
# Handle encryption
|
|
data = self.decipher(self.objid, self.genno, data)
|
|
if gen_xref_stm:
|
|
self.decdata = data # keep decrypted data
|
|
if 'Filter' not in self.dic:
|
|
self.data = data
|
|
self.rawdata = None
|
|
return
|
|
filters = self.dic['Filter']
|
|
if not isinstance(filters, list):
|
|
filters = [ filters ]
|
|
for f in filters:
|
|
if f in LITERALS_FLATE_DECODE:
|
|
# will get errors if the document is encrypted.
|
|
data = zlib.decompress(data)
|
|
# elif f in LITERALS_LZW_DECODE:
|
|
# data = b''.join(LZWDecoder(BytesIO(data)).run())
|
|
elif f in LITERALS_ASCII85_DECODE:
|
|
data = ascii85decode(data)
|
|
elif f == LITERAL_CRYPT:
|
|
raise PDFNotImplementedError('/Crypt filter is unsupported')
|
|
else:
|
|
raise PDFNotImplementedError('Unsupported filter: %r' % f)
|
|
# apply predictors
|
|
if 'DP' in self.dic:
|
|
params = self.dic['DP']
|
|
else:
|
|
params = self.dic.get('DecodeParms', {})
|
|
if 'Predictor' in params:
|
|
pred = int_value(params['Predictor'])
|
|
if pred:
|
|
if pred != 12:
|
|
raise PDFNotImplementedError(
|
|
'Unsupported predictor: %r' % pred)
|
|
if 'Columns' not in params:
|
|
raise PDFValueError(
|
|
'Columns undefined for predictor=12')
|
|
columns = int_value(params['Columns'])
|
|
buf = b''
|
|
ent0 = b'\x00' * columns
|
|
for i in range(0, len(data), columns+1):
|
|
pred = data[i]
|
|
ent1 = data[i+1:i+1+columns]
|
|
if sys.version_info[0] == 2:
|
|
if pred == '\x02':
|
|
ent1 = ''.join(chr((ord(a)+ord(b)) & 255) \
|
|
for (a,b) in zip(ent0,ent1))
|
|
else:
|
|
if pred == 2:
|
|
ent1 = b''.join(bytes([(a+b) & 255]) \
|
|
for (a,b) in zip(ent0,ent1))
|
|
buf += ent1
|
|
ent0 = ent1
|
|
data = buf
|
|
self.data = data
|
|
self.rawdata = None
|
|
return
|
|
|
|
def get_data(self):
|
|
if self.data is None:
|
|
self.decode()
|
|
return self.data
|
|
|
|
def get_rawdata(self):
|
|
return self.rawdata
|
|
|
|
def get_decdata(self):
|
|
if self.decdata is not None:
|
|
return self.decdata
|
|
data = self.rawdata
|
|
if self.decipher and data:
|
|
# 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 = LIT(b'ObjStm')
|
|
LITERAL_XREF = LIT(b'XRef')
|
|
LITERAL_PAGE = LIT(b'Page')
|
|
LITERAL_PAGES = LIT(b'Pages')
|
|
LITERAL_CATALOG = LIT(b'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 iter(self.offsets.keys())
|
|
|
|
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(b'trailer'):
|
|
parser.seek(pos)
|
|
break
|
|
f = line.strip().split(b' ')
|
|
if len(f) != 2:
|
|
raise PDFNoValidXRef('Trailer not found: %r: line=%r' % (parser, line))
|
|
try:
|
|
(start, nobjs) = map(int, f)
|
|
except ValueError:
|
|
raise PDFNoValidXRef('Invalid line: %r: line=%r' % (parser, line))
|
|
for objid in range(start, start+nobjs):
|
|
try:
|
|
(_, line) = parser.nextline()
|
|
except PSEOF:
|
|
raise PDFNoValidXRef('Unexpected EOF - file corrupted?')
|
|
f = line.strip().split(b' ')
|
|
if len(f) != 3:
|
|
raise PDFNoValidXRef('Invalid XRef format: %r, line=%r' % (parser, line))
|
|
(pos, genno, use) = f
|
|
if use != b'n':
|
|
continue
|
|
self.offsets[objid] = (int(genno.decode('utf-8')), int(pos.decode('utf-8')))
|
|
self.load_trailer(parser)
|
|
return
|
|
|
|
KEYWORD_TRAILER = KWD(b'trailer')
|
|
def load_trailer(self, parser):
|
|
try:
|
|
(_,kwd) = parser.nexttoken()
|
|
assert kwd is self.KEYWORD_TRAILER
|
|
(_,dic) = parser.nextobject(direct=True)
|
|
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)
|
|
|
|
|
|
## PDFXRefStream
|
|
##
|
|
class PDFXRefStream(object):
|
|
|
|
def __init__(self):
|
|
self.index = None
|
|
self.data = None
|
|
self.entlen = None
|
|
self.fl1 = self.fl2 = self.fl3 = None
|
|
return
|
|
|
|
def __repr__(self):
|
|
return '<PDFXRef: objids=%s>' % self.index
|
|
|
|
def objids(self):
|
|
for first, size in self.index:
|
|
for objid in range(first, first + size):
|
|
yield objid
|
|
|
|
def load(self, parser, debug=0):
|
|
(_,objid) = parser.nexttoken() # ignored
|
|
(_,genno) = parser.nexttoken() # ignored
|
|
(_,kwd) = parser.nexttoken()
|
|
(_,stream) = parser.nextobject()
|
|
if not isinstance(stream, PDFStream) or \
|
|
stream.dic['Type'] is not LITERAL_XREF:
|
|
raise PDFNoValidXRef('Invalid PDF stream spec.')
|
|
size = stream.dic['Size']
|
|
index = stream.dic.get('Index', (0,size))
|
|
self.index = list(zip(itertools.islice(index, 0, None, 2),
|
|
itertools.islice(index, 1, None, 2)))
|
|
(self.fl1, self.fl2, self.fl3) = stream.dic['W']
|
|
self.data = stream.get_data()
|
|
self.entlen = self.fl1+self.fl2+self.fl3
|
|
self.trailer = stream.dic
|
|
return
|
|
|
|
def getpos(self, objid):
|
|
offset = 0
|
|
for first, size in self.index:
|
|
if first <= objid and objid < (first + size):
|
|
break
|
|
offset += size
|
|
else:
|
|
raise KeyError(objid)
|
|
i = self.entlen * ((objid - first) + offset)
|
|
ent = self.data[i:i+self.entlen]
|
|
f1 = nunpack(ent[:self.fl1], 1)
|
|
if f1 == 1:
|
|
pos = nunpack(ent[self.fl1:self.fl1+self.fl2])
|
|
genno = nunpack(ent[self.fl1+self.fl2:])
|
|
return (None, pos)
|
|
elif f1 == 2:
|
|
objid = nunpack(ent[self.fl1:self.fl1+self.fl2])
|
|
index = nunpack(ent[self.fl1+self.fl2:])
|
|
return (objid, index)
|
|
# this is a free object
|
|
raise KeyError(objid)
|
|
|
|
|
|
## 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
|
|
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
|
|
try:
|
|
self.encryption = (list_value(trailer['ID']),
|
|
dict_value(trailer['Encrypt']))
|
|
# fix for bad files
|
|
except:
|
|
self.encryption = (b'ffffffffffffffffffffffffffffffffffff',
|
|
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=b'', inept=True):
|
|
if not self.encryption:
|
|
self.is_printable = self.is_modifiable = self.is_extractable = True
|
|
self.ready = True
|
|
raise PDFEncryptionError('Document is not encrypted.')
|
|
return
|
|
(docid, param) = self.encryption
|
|
type = literal_name(param['Filter'])
|
|
if type == 'Adobe.APS':
|
|
return self.initialize_adobe_ps(password, docid, param)
|
|
if type == 'Standard':
|
|
return self.initialize_standard(password, docid, param)
|
|
if type == 'EBX_HANDLER' and inept is True:
|
|
return self.initialize_ebx_inept(password, docid, param)
|
|
if type == 'EBX_HANDLER' and inept is False:
|
|
return self.initialize_ebx_ignoble(password, docid, param)
|
|
|
|
raise PDFEncryptionError('Unknown filter: param=%r' % param)
|
|
|
|
def initialize_and_return_filter(self):
|
|
if not self.encryption:
|
|
self.is_printable = self.is_modifiable = self.is_extractable = True
|
|
self.ready = True
|
|
return None
|
|
|
|
(docid, param) = self.encryption
|
|
type = literal_name(param['Filter'])
|
|
return type
|
|
|
|
def initialize_adobe_ps(self, password, docid, param):
|
|
global KEYFILEPATH
|
|
self.decrypt_key = self.genkey_adobe_ps(param)
|
|
self.genkey = self.genkey_v4
|
|
self.decipher = self.decrypt_aes
|
|
self.ready = True
|
|
return
|
|
|
|
def genkey_adobe_ps(self, param):
|
|
# nice little offline principal keys dictionary
|
|
# global static principal key for German Onleihe / Bibliothek Digital
|
|
principalkeys = { b'bibliothek-digital.de': codecs.decode(b'rRwGv2tbpKov1krvv7PO0ws9S436/lArPlfipz5Pqhw=','base64')}
|
|
self.is_printable = self.is_modifiable = self.is_extractable = True
|
|
length = int_value(param.get('Length', 0)) // 8
|
|
edcdata = str_value(param.get('EDCData')).decode('base64')
|
|
pdrllic = str_value(param.get('PDRLLic')).decode('base64')
|
|
pdrlpol = str_value(param.get('PDRLPol')).decode('base64')
|
|
edclist = []
|
|
for pair in edcdata.split(b'\n'):
|
|
edclist.append(pair)
|
|
# principal key request
|
|
for key in principalkeys:
|
|
if key in pdrllic:
|
|
principalkey = principalkeys[key]
|
|
else:
|
|
raise ADEPTError('Cannot find principal key for this pdf')
|
|
shakey = SHA256(principalkey)
|
|
ivector = bytes(16) # 16 zero bytes
|
|
plaintext = AES.new(shakey,AES.MODE_CBC,ivector).decrypt(edclist[9].decode('base64'))
|
|
if plaintext[-16:] != bytearray(b'\0x10')*16:
|
|
raise ADEPTError('Offlinekey cannot be decrypted, aborting ...')
|
|
pdrlpol = AES.new(plaintext[16:32],AES.MODE_CBC,edclist[2].decode('base64')).decrypt(pdrlpol)
|
|
if pdrlpol[-1] < 1 or pdrlpol[-1] > 16:
|
|
raise ADEPTError('Could not decrypt PDRLPol, aborting ...')
|
|
else:
|
|
cutter = -1 * pdrlpol[-1]
|
|
pdrlpol = pdrlpol[:cutter]
|
|
return plaintext[:16]
|
|
|
|
PASSWORD_PADDING = b'(\xbfN^Nu\x8aAd\x00NV\xff\xfa\x01\x08..' \
|
|
b'\x00\xb6\xd0h>\x80/\x0c\xa9\xfedSiz'
|
|
# experimental aes pw support
|
|
|
|
def check_user_password(self, password, docid, param):
|
|
V = int_value(param.get('V', 0))
|
|
if V < 5:
|
|
return self.check_user_password_V4(password, docid, param)
|
|
else:
|
|
return self.check_user_password_V5(password, param)
|
|
|
|
def check_owner_password(self, password, docid, param):
|
|
V = int_value(param.get('V', 0))
|
|
if V < 5:
|
|
return self.check_owner_password_V4(password, docid, param)
|
|
else:
|
|
return self.check_owner_password_V5(password, param)
|
|
|
|
def check_user_password_V5(self, password, param):
|
|
U = str_value(param['U'])
|
|
userdata = U[:32]
|
|
salt = U[32:32+8]
|
|
# Truncate password:
|
|
password = password[:min(127, len(password))]
|
|
if self.hash_V5(password, salt, b"", param) == userdata:
|
|
return True
|
|
return None
|
|
|
|
def check_owner_password_V5(self, password, param):
|
|
U = str_value(param['U'])
|
|
O = str_value(param['O'])
|
|
userdata = U[:48]
|
|
ownerdata = O[:32]
|
|
salt = O[32:32+8]
|
|
# Truncate password:
|
|
password = password[:min(127, len(password))]
|
|
if self.hash_V5(password, salt, userdata, param) == ownerdata:
|
|
return True
|
|
return None
|
|
|
|
def recover_encryption_key_with_password(self, password, docid, param):
|
|
# Truncate password:
|
|
key_password = password[:min(127, len(password))]
|
|
|
|
if self.check_owner_password_V5(key_password, param):
|
|
O = str_value(param['O'])
|
|
U = str_value(param['U'])
|
|
OE = str_value(param['OE'])
|
|
key_salt = O[40:40+8]
|
|
user_data = U[:48]
|
|
encrypted_file_key = OE[:32]
|
|
elif self.check_user_password_V5(key_password, param):
|
|
U = str_value(param['U'])
|
|
UE = str_value(param['UE'])
|
|
key_salt = U[40:40+8]
|
|
user_data = b""
|
|
encrypted_file_key = UE[:32]
|
|
else:
|
|
raise Exception("Trying to recover key, but neither user nor owner pass is correct.")
|
|
|
|
intermediate_key = self.hash_V5(key_password, key_salt, user_data, param)
|
|
|
|
file_key = self.process_with_aes(intermediate_key, False, encrypted_file_key)
|
|
|
|
return file_key
|
|
|
|
|
|
def process_with_aes(self, key, encrypt, data, repetitions = 1, iv = None):
|
|
if iv is None:
|
|
keylen = len(key)
|
|
iv = bytes([0x00]*keylen)
|
|
|
|
if not encrypt:
|
|
plaintext = AES.new(key,AES.MODE_CBC,iv, True).decrypt(data)
|
|
return plaintext
|
|
else:
|
|
aes = AES.new(key, AES.MODE_CBC, iv, False)
|
|
new_data = bytes(data * repetitions)
|
|
crypt = aes.encrypt(new_data)
|
|
return crypt
|
|
|
|
|
|
def hash_V5(self, password, salt, userdata, param):
|
|
R = int_value(param['R'])
|
|
K = SHA256(password + salt + userdata)
|
|
if R < 6:
|
|
return K
|
|
elif R == 6:
|
|
round_number = 0
|
|
done = False
|
|
while (not done):
|
|
round_number = round_number + 1
|
|
K1 = password + K + userdata
|
|
if len(K1) < 32:
|
|
raise Exception("K1 < 32 ...")
|
|
#def process_with_aes(self, key: bytes, encrypt: bool, data: bytes, repetitions: int = 1, iv: bytes = None):
|
|
E = self.process_with_aes(K[:16], True, K1, 64, K[16:32])
|
|
K = (hashlib.sha256, hashlib.sha384, hashlib.sha512)[sum(E) % 3](E).digest()
|
|
|
|
if round_number >= 64:
|
|
ch = int.from_bytes(E[-1:], "big", signed=False)
|
|
if ch <= round_number - 32:
|
|
done = True
|
|
|
|
result = K[0:32]
|
|
return result
|
|
else:
|
|
raise NotImplementedError("Revision > 6 not supported.")
|
|
|
|
|
|
def check_owner_password_V4(self, password, docid, param):
|
|
|
|
# compute_O_rc4_key:
|
|
V = int_value(param.get('V', 0))
|
|
if V >= 5:
|
|
raise Exception("compute_O_rc4_key not possible with V>= 5")
|
|
|
|
R = int_value(param.get('R', 0))
|
|
|
|
length = int_value(param.get('Length', 40)) # Key length (bits)
|
|
password = (password+self.PASSWORD_PADDING)[:32]
|
|
hash = hashlib.md5(password)
|
|
if R >= 3:
|
|
for _ in range(50):
|
|
hash = hashlib.md5(hash.digest()[:length//8])
|
|
hash = hash.digest()[:length//8]
|
|
|
|
# "hash" is the return value of compute_O_rc4_key
|
|
|
|
Odata = str_value(param.get('O'))
|
|
# now call iterate_rc4 ...
|
|
x = ARC4.new(hash).decrypt(Odata) # 4
|
|
if R >= 3:
|
|
for i in range(1,19+1):
|
|
if sys.version_info[0] == 2:
|
|
k = b''.join(chr(ord(c) ^ i) for c in hash )
|
|
else:
|
|
k = b''.join(bytes([c ^ i]) for c in hash )
|
|
x = ARC4.new(k).decrypt(x)
|
|
|
|
|
|
# "x" is now the padded user password.
|
|
|
|
# If we wanted to recover / extract the user password,
|
|
# we'd need to trim off the padding string from the end.
|
|
# As we just want to get access to the encryption key,
|
|
# we can just hand the password into the check_user_password
|
|
# as it is, as that function would be adding padding anyways.
|
|
# This trick only works with V4 and lower.
|
|
|
|
enc_key = self.check_user_password(x, docid, param)
|
|
if enc_key is not None:
|
|
return enc_key
|
|
|
|
return False
|
|
|
|
|
|
|
|
|
|
def check_user_password_V4(self, password, docid, param):
|
|
|
|
V = int_value(param.get('V', 0))
|
|
length = int_value(param.get('Length', 40)) # Key length (bits)
|
|
O = str_value(param['O'])
|
|
R = int_value(param['R']) # Revision
|
|
U = str_value(param['U'])
|
|
P = int_value(param['P'])
|
|
|
|
# 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
|
|
# aes special handling if metadata isn't encrypted
|
|
try:
|
|
EncMetadata = str_value(param['EncryptMetadata'])
|
|
except:
|
|
EncMetadata = b'True'
|
|
if (EncMetadata == ('False' or 'false') or V < 4) and R >= 4:
|
|
hash.update(codecs.decode(b'ffffffff','hex'))
|
|
if R >= 3:
|
|
# 8
|
|
for _ in range(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 range(1,19+1):
|
|
if sys.version_info[0] == 2:
|
|
k = b''.join(chr(ord(c) ^ i) for c in key )
|
|
else:
|
|
k = b''.join(bytes([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 is_authenticated:
|
|
return key
|
|
|
|
return None
|
|
|
|
def initialize_standard(self, password, docid, param):
|
|
|
|
self.decrypt_key = None
|
|
|
|
|
|
# copy from a global variable
|
|
V = int_value(param.get('V', 0))
|
|
if (V <=0 or V > 5):
|
|
raise PDFEncryptionError('Unknown algorithm: %r' % V)
|
|
R = int_value(param['R']) # Revision
|
|
if R >= 7:
|
|
raise PDFEncryptionError('Unknown revision: %r' % R)
|
|
|
|
# check owner pass:
|
|
retval = self.check_owner_password(password, docid, param)
|
|
if retval is True or (retval is not False and retval is not None):
|
|
#print("Owner pass is valid")
|
|
if retval is True:
|
|
self.decrypt_key = self.recover_encryption_key_with_password(password, docid, param)
|
|
else:
|
|
self.decrypt_key = retval
|
|
|
|
if self.decrypt_key is None or self.decrypt_key is True or self.decrypt_key is False:
|
|
# That's not the owner password. Check if it's the user password.
|
|
retval = self.check_user_password(password, docid, param)
|
|
if retval is True or (retval is not False and retval is not None):
|
|
#print("User pass is valid")
|
|
if retval is True:
|
|
self.decrypt_key = self.recover_encryption_key_with_password(password, docid, param)
|
|
else:
|
|
self.decrypt_key = retval
|
|
|
|
if self.decrypt_key is None or self.decrypt_key is True or self.decrypt_key is False:
|
|
raise ADEPTInvalidPasswordError("Password invalid.")
|
|
|
|
|
|
P = int_value(param['P'])
|
|
|
|
self.is_printable = bool(P & 4)
|
|
self.is_modifiable = bool(P & 8)
|
|
self.is_extractable = bool(P & 16)
|
|
self.is_annotationable = bool(P & 32)
|
|
self.is_formsenabled = bool(P & 256)
|
|
self.is_textextractable = bool(P & 512)
|
|
self.is_assemblable = bool(P & 1024)
|
|
self.is_formprintable = bool(P & 2048)
|
|
|
|
|
|
# genkey method
|
|
if V == 1 or V == 2 or V == 4:
|
|
self.genkey = self.genkey_v2
|
|
elif V == 3:
|
|
self.genkey = self.genkey_v3
|
|
elif V >= 5:
|
|
self.genkey = self.genkey_v5
|
|
|
|
set_decipher = False
|
|
|
|
if V >= 4:
|
|
# Check if we need new genkey_v4 - only if we're using AES.
|
|
try:
|
|
for key in param['CF']:
|
|
algo = str(param["CF"][key]["CFM"])
|
|
if algo == "/AESV2":
|
|
if V == 4:
|
|
self.genkey = self.genkey_v4
|
|
set_decipher = True
|
|
self.decipher = self.decrypt_aes
|
|
elif algo == "/AESV3":
|
|
if V == 4:
|
|
self.genkey = self.genkey_v4
|
|
set_decipher = True
|
|
self.decipher = self.decrypt_aes
|
|
elif algo == "/V2":
|
|
set_decipher = True
|
|
self.decipher = self.decrypt_rc4
|
|
except:
|
|
pass
|
|
|
|
# rc4
|
|
if V < 4:
|
|
self.decipher = self.decrypt_rc4 # XXX may be AES
|
|
# aes
|
|
if not set_decipher:
|
|
# This should usually already be set by now.
|
|
# If it's not, assume that V4 and newer are using AES
|
|
if V >= 4:
|
|
self.decipher = self.decrypt_aes
|
|
self.ready = True
|
|
return
|
|
|
|
|
|
def initialize_ebx_ignoble(self, keyb64, docid, param):
|
|
self.is_printable = self.is_modifiable = self.is_extractable = True
|
|
|
|
try:
|
|
key = keyb64.decode('base64')[:16]
|
|
# This will probably always error, but I'm not 100% sure, so lets leave the old code in.
|
|
except AttributeError:
|
|
key = codecs.decode(keyb64.encode("ascii"), 'base64')[:16]
|
|
|
|
|
|
length = int_value(param.get('Length', 0)) / 8
|
|
rights = codecs.decode(str_value(param.get('ADEPT_LICENSE')), "base64")
|
|
rights = zlib.decompress(rights, -15)
|
|
rights = etree.fromstring(rights)
|
|
expr = './/{http://ns.adobe.com/adept}encryptedKey'
|
|
bookkey = ''.join(rights.findtext(expr))
|
|
bookkey = base64.b64decode(bookkey)
|
|
bookkey = AES.new(key, AES.MODE_CBC, b'\x00'*16).decrypt(bookkey)
|
|
bookkey = unpad(bookkey, 16) # PKCS#7
|
|
if len(bookkey) > 16:
|
|
bookkey = bookkey[-16:]
|
|
ebx_V = int_value(param.get('V', 4))
|
|
ebx_type = int_value(param.get('EBX_ENCRYPTIONTYPE', 6))
|
|
# added because of improper booktype / decryption book session key errors
|
|
if length > 0:
|
|
if len(bookkey) == length:
|
|
if ebx_V == 3:
|
|
V = 3
|
|
else:
|
|
V = 2
|
|
elif len(bookkey) == length + 1:
|
|
V = bookkey[0]
|
|
bookkey = bookkey[1:]
|
|
else:
|
|
print("ebx_V is %d and ebx_type is %d" % (ebx_V, ebx_type))
|
|
print("length is %d and len(bookkey) is %d" % (length, len(bookkey)))
|
|
if len(bookkey) > 0:
|
|
print("bookkey[0] is %d" % bookkey[0])
|
|
raise ADEPTError('error decrypting book session key - mismatched length')
|
|
else:
|
|
# proper length unknown try with whatever you have
|
|
print("ebx_V is %d and ebx_type is %d" % (ebx_V, ebx_type))
|
|
print("length is %d and len(bookkey) is %d" % (length, len(bookkey)))
|
|
if len(bookkey) > 0:
|
|
print("bookkey[0] is %d" % ord(bookkey[0]))
|
|
if ebx_V == 3:
|
|
V = 3
|
|
else:
|
|
V = 2
|
|
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
|
|
|
|
@staticmethod
|
|
def removeHardening(rights, keytype, keydata):
|
|
adept = lambda tag: '{%s}%s' % ('http://ns.adobe.com/adept', tag)
|
|
textGetter = lambda name: ''.join(rights.findtext('.//%s' % (adept(name),)))
|
|
|
|
# Gather what we need, and generate the IV
|
|
resourceuuid = UUID(textGetter("resource"))
|
|
deviceuuid = UUID(textGetter("device"))
|
|
fullfillmentuuid = UUID(textGetter("fulfillment")[:36])
|
|
kekiv = UUID(int=resourceuuid.int ^ deviceuuid.int ^ fullfillmentuuid.int).bytes
|
|
|
|
# Derive kek from just "keytype"
|
|
rem = int(keytype, 10) % 16
|
|
H = SHA256(keytype.encode("ascii"))
|
|
kek = H[2*rem : 16 + rem] + H[rem : 2*rem]
|
|
|
|
return unpad(AES.new(kek, AES.MODE_CBC, kekiv).decrypt(keydata), 16)
|
|
|
|
def initialize_ebx_inept(self, password, docid, param):
|
|
self.is_printable = self.is_modifiable = self.is_extractable = True
|
|
rsakey = RSA.importKey(password) # parses the ASN1 structure
|
|
length = int_value(param.get('Length', 0)) // 8
|
|
rights = codecs.decode(param.get('ADEPT_LICENSE'), 'base64')
|
|
rights = zlib.decompress(rights, -15)
|
|
rights = etree.fromstring(rights)
|
|
expr = './/{http://ns.adobe.com/adept}encryptedKey'
|
|
bookkeyelem = rights.find(expr)
|
|
bookkey = codecs.decode(bookkeyelem.text.encode('utf-8'),'base64')
|
|
keytype = bookkeyelem.attrib.get('keyType', '0')
|
|
|
|
if int(keytype, 10) > 2:
|
|
bookkey = PDFDocument.removeHardening(rights, keytype, bookkey)
|
|
try:
|
|
bookkey = PKCS1_v1_5.new(rsakey).decrypt(bookkey, None) # automatically unpads
|
|
except ValueError:
|
|
bookkey = None
|
|
|
|
if bookkey is None:
|
|
raise ADEPTError('error decrypting book session key')
|
|
|
|
ebx_V = int_value(param.get('V', 4))
|
|
ebx_type = int_value(param.get('EBX_ENCRYPTIONTYPE', 6))
|
|
# added because of improper booktype / decryption book session key errors
|
|
if length > 0:
|
|
if len(bookkey) == length:
|
|
if ebx_V == 3:
|
|
V = 3
|
|
else:
|
|
V = 2
|
|
elif len(bookkey) == length + 1:
|
|
V = bookkey[0]
|
|
bookkey = bookkey[1:]
|
|
else:
|
|
print("ebx_V is %d and ebx_type is %d" % (ebx_V, ebx_type))
|
|
print("length is %d and len(bookkey) is %d" % (length, len(bookkey)))
|
|
if len(bookkey) > 0:
|
|
print("bookkey[0] is %d" % bookkey[0])
|
|
raise ADEPTError('error decrypting book session key - mismatched length')
|
|
else:
|
|
# proper length unknown try with whatever you have
|
|
print("ebx_V is %d and ebx_type is %d" % (ebx_V, ebx_type))
|
|
print("length is %d and len(bookkey) is %d" % (length, len(bookkey)))
|
|
if len(bookkey) > 0:
|
|
print("bookkey[0] is %d" % bookkey[0])
|
|
if ebx_V == 3:
|
|
V = 3
|
|
else:
|
|
V = 2
|
|
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
|
|
|
|
# genkey functions
|
|
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 += bytes([objid[0], genno[0], objid[1], genno[1], objid[2]]) + b'sAlT'
|
|
hash = hashlib.md5(key)
|
|
key = hash.digest()[:min(len(self.decrypt_key) + 5, 16)]
|
|
return key
|
|
|
|
# aes v2 and v4 algorithm
|
|
def genkey_v4(self, objid, genno):
|
|
objid = struct.pack('<L', objid)[:3]
|
|
genno = struct.pack('<L', genno)[:2]
|
|
key = self.decrypt_key + objid + genno + b'sAlT'
|
|
hash = hashlib.md5(key)
|
|
key = hash.digest()[:min(len(self.decrypt_key) + 5, 16)]
|
|
return key
|
|
|
|
def genkey_v5(self, objid, genno):
|
|
# Looks like they stopped this useless obfuscation.
|
|
return self.decrypt_key
|
|
|
|
def decrypt_aes(self, objid, genno, data):
|
|
key = self.genkey(objid, genno)
|
|
ivector = data[:16]
|
|
data = data[16:]
|
|
plaintext = AES.new(key,AES.MODE_CBC,ivector).decrypt(data)
|
|
# remove pkcs#5 aes padding
|
|
if sys.version_info[0] == 2:
|
|
cutter = -1 * ord(plaintext[-1])
|
|
else:
|
|
cutter = -1 * plaintext[-1]
|
|
|
|
plaintext = plaintext[:cutter]
|
|
return plaintext
|
|
|
|
def decrypt_rc4(self, objid, genno, data):
|
|
key = self.genkey(objid, genno)
|
|
return ARC4.new(key).decrypt(data)
|
|
|
|
|
|
KEYWORD_OBJ = KWD(b'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:
|
|
(stmid, index) = xref.getpos(objid)
|
|
break
|
|
except KeyError:
|
|
pass
|
|
else:
|
|
#if STRICT:
|
|
# raise PDFSyntaxError('Cannot locate objid=%r' % objid)
|
|
return None
|
|
if stmid:
|
|
if gen_xref_stm:
|
|
return PDFObjStmRef(objid, stmid, index)
|
|
# Stuff from pdfminer: extract objects from object stream
|
|
stream = stream_value(self.getobj(stmid))
|
|
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 stmid in self.parsed_objs:
|
|
objs = self.parsed_objs[stmid]
|
|
else:
|
|
parser = PDFObjStrmParser(stream.get_data(), self)
|
|
objs = []
|
|
try:
|
|
while 1:
|
|
(_,obj) = parser.nextobject()
|
|
objs.append(obj)
|
|
except PSEOF:
|
|
pass
|
|
self.parsed_objs[stmid] = objs
|
|
genno = 0
|
|
i = n*2+index
|
|
try:
|
|
obj = objs[i]
|
|
except IndexError:
|
|
# This IndexError used to just raise an exception.
|
|
# Unfortunately that seems to break some PDFs, see this issue:
|
|
# https://github.com/noDRM/DeDRM_tools/issues/233
|
|
# I'm not sure why this is the case, but lets try only raising that exception
|
|
# when in STRICT mode, and make it a warning otherwise.
|
|
if STRICT:
|
|
raise PDFSyntaxError('Invalid object number: objid=%r' % (objid))
|
|
|
|
print('Invalid object number: objid=%r' % (objid))
|
|
print("Continuing anyways?")
|
|
print("If the resulting PDF is corrupted, please open a bug report.")
|
|
return None
|
|
|
|
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()
|
|
# #### hack around malformed pdf files
|
|
# assert objid1 == objid, (objid, objid1)
|
|
## if objid1 != objid:
|
|
## x = []
|
|
## while kwd is not self.KEYWORD_OBJ:
|
|
## (_,kwd) = self.parser.nexttoken()
|
|
## x.append(kwd)
|
|
## if x:
|
|
## objid1 = x[-2]
|
|
## genno = x[-1]
|
|
##
|
|
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)
|
|
if self.decipher:
|
|
obj = decipher_all(self.decipher, objid, genno, obj)
|
|
self.objs[objid] = obj
|
|
return obj
|
|
|
|
|
|
class PDFObjStmRef(object):
|
|
maxindex = 0
|
|
def __init__(self, objid, stmid, index):
|
|
self.objid = objid
|
|
self.stmid = stmid
|
|
self.index = index
|
|
if index > PDFObjStmRef.maxindex:
|
|
PDFObjStmRef.maxindex = index
|
|
|
|
|
|
## 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 = KWD(b'R')
|
|
KEYWORD_ENDOBJ = KWD(b'endobj')
|
|
KEYWORD_STREAM = KWD(b'stream')
|
|
KEYWORD_XREF = KWD(b'xref')
|
|
KEYWORD_STARTXREF = KWD(b'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 b'endstream' in line:
|
|
i = line.index(b'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 == b'startxref': break
|
|
if line:
|
|
prev = line
|
|
else:
|
|
raise PDFNoValidXRef('Unexpected EOF')
|
|
return int(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 isinstance(token, int):
|
|
# XRefStream: PDF-1.5
|
|
if GEN_XREF_STM == 1:
|
|
global gen_xref_stm
|
|
gen_xref_stm = True
|
|
self.seek(pos)
|
|
self.reset()
|
|
xref = PDFXRefStream()
|
|
xref.load(self)
|
|
else:
|
|
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 'XRefStm' in trailer:
|
|
pos = int_value(trailer['XRefStm'])
|
|
self.read_xref_from(pos, xrefs)
|
|
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 = []
|
|
trailerpos = None
|
|
try:
|
|
pos = self.find_xref()
|
|
self.read_xref_from(pos, xrefs)
|
|
except PDFNoValidXRef:
|
|
# fallback
|
|
self.seek(0)
|
|
pat = re.compile(b'^(\\d+)\\s+(\\d+)\\s+obj\\b')
|
|
offsets = {}
|
|
xref = PDFXRef()
|
|
while 1:
|
|
try:
|
|
(pos, line) = self.nextline()
|
|
except PSEOF:
|
|
break
|
|
if line.startswith(b'trailer'):
|
|
trailerpos = pos # remember last trailer
|
|
m = pat.match(line)
|
|
if not m: continue
|
|
(objid, genno) = m.groups()
|
|
offsets[int(objid)] = (0, pos)
|
|
if not offsets: raise
|
|
xref.offsets = offsets
|
|
if trailerpos:
|
|
self.seek(trailerpos)
|
|
xref.load_trailer(self)
|
|
xrefs.append(xref)
|
|
return xrefs
|
|
|
|
## PDFObjStrmParser
|
|
##
|
|
class PDFObjStrmParser(PDFParser):
|
|
|
|
def __init__(self, data, doc):
|
|
PSStackParser.__init__(self, BytesIO(data))
|
|
self.doc = doc
|
|
return
|
|
|
|
def flush(self):
|
|
self.add_results(*self.popall())
|
|
return
|
|
|
|
KEYWORD_R = KWD(b'R')
|
|
def do_keyword(self, pos, token):
|
|
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
|
|
# others
|
|
self.push((pos, token))
|
|
return
|
|
|
|
|
|
# Takes a PDF file name as input, and if this is an ADE-protected PDF,
|
|
# returns the UUID of the user that's licensed to open this file.
|
|
def adeptGetUserUUID(inf):
|
|
try:
|
|
doc = PDFDocument()
|
|
inf = open(inf, 'rb')
|
|
pars = PDFParser(doc, inf)
|
|
|
|
(docid, param) = doc.encryption
|
|
type = literal_name(param['Filter'])
|
|
if type != 'EBX_HANDLER':
|
|
# No EBX_HANDLER, no idea which user key can decrypt this.
|
|
inf.close()
|
|
return None
|
|
|
|
rights = codecs.decode(param.get('ADEPT_LICENSE'), 'base64')
|
|
inf.close()
|
|
|
|
rights = zlib.decompress(rights, -15)
|
|
rights = etree.fromstring(rights)
|
|
expr = './/{http://ns.adobe.com/adept}user'
|
|
user_uuid = ''.join(rights.findtext(expr))
|
|
if user_uuid[:9] != "urn:uuid:":
|
|
return None
|
|
return user_uuid[9:]
|
|
|
|
except:
|
|
return None
|
|
|
|
###
|
|
### My own code, for which there is none else to blame
|
|
|
|
class PDFSerializer(object):
|
|
def __init__(self, inf, userkey, inept=True):
|
|
global GEN_XREF_STM, gen_xref_stm
|
|
gen_xref_stm = GEN_XREF_STM > 1
|
|
self.version = inf.read(8)
|
|
inf.seek(0)
|
|
self.doc = doc = PDFDocument()
|
|
parser = PDFParser(doc, inf)
|
|
doc.initialize(userkey, inept)
|
|
self.objids = objids = set()
|
|
for xref in reversed(doc.xrefs):
|
|
trailer = xref.trailer
|
|
for objid in xref.objids():
|
|
objids.add(objid)
|
|
trailer = dict(trailer)
|
|
trailer.pop('Prev', None)
|
|
trailer.pop('XRefStm', None)
|
|
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(b'\n%\xe2\xe3\xcf\xd3\n')
|
|
doc = self.doc
|
|
objids = self.objids
|
|
xrefs = {}
|
|
maxobj = max(objids)
|
|
trailer = dict(self.trailer)
|
|
trailer['Size'] = maxobj + 1
|
|
for objid in objids:
|
|
obj = doc.getobj(objid)
|
|
if isinstance(obj, PDFObjStmRef):
|
|
xrefs[objid] = obj
|
|
continue
|
|
if obj is not None:
|
|
try:
|
|
genno = obj.genno
|
|
except AttributeError:
|
|
genno = 0
|
|
xrefs[objid] = (self.tell(), genno)
|
|
self.serialize_indirect(objid, obj)
|
|
startxref = self.tell()
|
|
|
|
if not gen_xref_stm:
|
|
self.write(b'xref\n')
|
|
self.write(b'0 %d\n' % (maxobj + 1,))
|
|
for objid in range(0, maxobj + 1):
|
|
if objid in xrefs:
|
|
# force the genno to be 0
|
|
self.write(b"%010d 00000 n \n" % xrefs[objid][0])
|
|
else:
|
|
self.write(b"%010d %05d f \n" % (0, 65535))
|
|
|
|
self.write(b'trailer\n')
|
|
self.serialize_object(trailer)
|
|
self.write(b'\nstartxref\n%d\n%%%%EOF' % startxref)
|
|
|
|
else: # Generate crossref stream.
|
|
|
|
# Calculate size of entries
|
|
maxoffset = max(startxref, maxobj)
|
|
maxindex = PDFObjStmRef.maxindex
|
|
fl2 = 2
|
|
power = 65536
|
|
while maxoffset >= power:
|
|
fl2 += 1
|
|
power *= 256
|
|
fl3 = 1
|
|
power = 256
|
|
while maxindex >= power:
|
|
fl3 += 1
|
|
power *= 256
|
|
|
|
index = []
|
|
first = None
|
|
prev = None
|
|
data = []
|
|
# Put the xrefstream's reference in itself
|
|
startxref = self.tell()
|
|
maxobj += 1
|
|
xrefs[maxobj] = (startxref, 0)
|
|
for objid in sorted(xrefs):
|
|
if first is None:
|
|
first = objid
|
|
elif objid != prev + 1:
|
|
index.extend((first, prev - first + 1))
|
|
first = objid
|
|
prev = objid
|
|
objref = xrefs[objid]
|
|
if isinstance(objref, PDFObjStmRef):
|
|
f1 = 2
|
|
f2 = objref.stmid
|
|
f3 = objref.index
|
|
else:
|
|
f1 = 1
|
|
f2 = objref[0]
|
|
# we force all generation numbers to be 0
|
|
# f3 = objref[1]
|
|
f3 = 0
|
|
|
|
data.append(struct.pack('>B', f1))
|
|
data.append(struct.pack('>L', f2)[-fl2:])
|
|
data.append(struct.pack('>L', f3)[-fl3:])
|
|
index.extend((first, prev - first + 1))
|
|
data = zlib.compress(b''.join(data))
|
|
dic = {'Type': LITERAL_XREF, 'Size': prev + 1, 'Index': index,
|
|
'W': [1, fl2, fl3], 'Length': len(data),
|
|
'Filter': LITERALS_FLATE_DECODE[0],
|
|
'Root': trailer['Root'],}
|
|
if 'Info' in trailer:
|
|
dic['Info'] = trailer['Info']
|
|
xrefstm = PDFStream(dic, data)
|
|
self.serialize_indirect(maxobj, xrefstm)
|
|
self.write(b'startxref\n%d\n%%%%EOF' % startxref)
|
|
def write(self, data):
|
|
self.outf.write(data)
|
|
self.last = data[-1:]
|
|
|
|
def tell(self):
|
|
return self.outf.tell()
|
|
|
|
def escape_string(self, string):
|
|
string = string.replace(b'\\', b'\\\\')
|
|
string = string.replace(b'\n', b'\\n')
|
|
string = string.replace(b'(', b'\\(')
|
|
string = string.replace(b')', b'\\)')
|
|
return string
|
|
|
|
def serialize_object(self, obj):
|
|
if isinstance(obj, dict):
|
|
# Correct malformed Mac OS resource forks for Stanza
|
|
if 'ResFork' in obj and 'Type' in obj and 'Subtype' not in obj \
|
|
and isinstance(obj['Type'], int):
|
|
obj['Subtype'] = obj['Type']
|
|
del obj['Type']
|
|
# end - hope this doesn't have bad effects
|
|
self.write(b'<<')
|
|
for key, val in obj.items():
|
|
self.write(str(LIT(key.encode('utf-8'))).encode('utf-8'))
|
|
self.serialize_object(val)
|
|
self.write(b'>>')
|
|
elif isinstance(obj, list):
|
|
self.write(b'[')
|
|
for val in obj:
|
|
self.serialize_object(val)
|
|
self.write(b']')
|
|
elif isinstance(obj, bytearray):
|
|
self.write(b'(%s)' % self.escape_string(obj))
|
|
elif isinstance(obj, bytes):
|
|
self.write(b'<%s>' % binascii.hexlify(obj).upper())
|
|
elif isinstance(obj, str):
|
|
self.write(b'(%s)' % self.escape_string(obj.encode('utf-8')))
|
|
elif isinstance(obj, bool):
|
|
if self.last.isalnum():
|
|
self.write(b' ')
|
|
self.write(str(obj).lower().encode('utf-8'))
|
|
elif isinstance(obj, int):
|
|
if self.last.isalnum():
|
|
self.write(b' ')
|
|
self.write(str(obj).encode('utf-8'))
|
|
elif isinstance(obj, Decimal):
|
|
if self.last.isalnum():
|
|
self.write(b' ')
|
|
self.write(str(obj).encode('utf-8'))
|
|
elif isinstance(obj, PDFObjRef):
|
|
if self.last.isalnum():
|
|
self.write(b' ')
|
|
self.write(b'%d %d R' % (obj.objid, 0))
|
|
elif isinstance(obj, PDFStream):
|
|
### If we don't generate cross ref streams the object streams
|
|
### are no longer useful, as we have extracted all objects from
|
|
### them. Therefore leave them out from the output.
|
|
if obj.dic.get('Type') == LITERAL_OBJSTM and not gen_xref_stm:
|
|
self.write(b'(deleted)')
|
|
else:
|
|
data = obj.get_decdata()
|
|
|
|
# Fix length:
|
|
# We've decompressed and then recompressed the PDF stream.
|
|
# Depending on the algorithm, the implementation, and the compression level,
|
|
# the resulting recompressed stream is unlikely to have the same length as the original.
|
|
# So we need to update the PDF object to contain the new proper length.
|
|
|
|
# Without this change, all PDFs exported by this plugin are slightly corrupted -
|
|
# even though most if not all PDF readers can correct that on-the-fly.
|
|
|
|
if 'Length' in obj.dic:
|
|
obj.dic['Length'] = len(data)
|
|
|
|
|
|
self.serialize_object(obj.dic)
|
|
self.write(b'stream\n')
|
|
self.write(data)
|
|
self.write(b'\nendstream')
|
|
else:
|
|
data = str(obj).encode('utf-8')
|
|
if bytes([data[0]]).isalnum() and self.last.isalnum():
|
|
self.write(b' ')
|
|
self.write(data)
|
|
|
|
def serialize_indirect(self, objid, obj):
|
|
self.write(b'%d 0 obj' % (objid,))
|
|
self.serialize_object(obj)
|
|
if self.last.isalnum():
|
|
self.write(b'\n')
|
|
self.write(b'endobj\n')
|
|
|
|
|
|
|
|
|
|
def decryptBook(userkey, inpath, outpath, inept=True):
|
|
with open(inpath, 'rb') as inf:
|
|
serializer = PDFSerializer(inf, userkey, inept)
|
|
with open(outpath, 'wb') as outf:
|
|
# help construct to make sure the method runs to the end
|
|
try:
|
|
serializer.dump(outf)
|
|
except Exception as e:
|
|
print("error writing pdf: {0}".format(e))
|
|
traceback.print_exc()
|
|
return 2
|
|
return 0
|
|
|
|
|
|
def getPDFencryptionType(inpath):
|
|
with open(inpath, 'rb') as inf:
|
|
doc = doc = PDFDocument()
|
|
parser = PDFParser(doc, inf)
|
|
filter = doc.initialize_and_return_filter()
|
|
return filter
|
|
|
|
|
|
def decryptPDF(inpath):
|
|
keypath = KEYPATH
|
|
outpath = os.path.basename(inpath).removesuffix(".pdf") + "_decrypted.pdf"
|
|
userkey = open(keypath,'rb').read()
|
|
result = decryptBook(userkey, inpath, outpath)
|
|
if result == 0:
|
|
print("Successfully decrypted")
|
|
return outpath
|
|
else:
|
|
print("Decryption failed")
|
|
return None
|
|
|
|
|