Files
addon/lib/jsunpack.py
2019-04-23 14:32:53 +02:00

110 lines
4.4 KiB
Python

# -*- coding: utf-8 -*-
"""
urlresolver XBMC Addon
Copyright (C) 2013 Bstrdsmkr
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
Adapted for use in xbmc from:
https://github.com/einars/js-beautify/blob/master/python/jsbeautifier/unpackers/packer.py
usage:
if detect(some_string):
unpacked = unpack(some_string)
Unpacker for Dean Edward's p.a.c.k.e.r
"""
import re
def detect(source):
"""Detects whether `source` is P.A.C.K.E.R. coded."""
source = source.replace(' ', '')
if re.search('eval\(function\(p,a,c,k,e,(?:r|d)', source):
return True
else:
return False
def unpack(source):
"""Unpacks P.A.C.K.E.R. packed js code."""
payload, symtab, radix, count = _filterargs(source)
if count != len(symtab):
raise UnpackingError('Malformed p.a.c.k.e.r. symtab.')
try:
unbase = Unbaser(radix)
except TypeError:
raise UnpackingError('Unknown p.a.c.k.e.r. encoding.')
def lookup(match):
"""Look up symbols in the synthetic symtab."""
word = match.group(0)
return symtab[unbase(word)] or word
source = re.sub(r'\b\w+\b', lookup, payload)
return _replacestrings(source)
def _filterargs(source):
"""Juice from a source file the four args needed by decoder."""
juicers = [(r"}\('(.*)', *(\d+), *(\d+), *'(.*)'\.split\('\|'\), *(\d+), *(.*)\)\)"),
(r"}\('(.*)', *(\d+), *(\d+), *'(.*)'\.split\('\|'\)"),
]
for juicer in juicers:
args = re.search(juicer, source, re.DOTALL)
if args:
a = args.groups()
try:
return a[0], a[3].split('|'), int(a[1]), int(a[2])
except ValueError:
raise UnpackingError('Corrupted p.a.c.k.e.r. data.')
# could not find a satisfying regex
raise UnpackingError('Could not make sense of p.a.c.k.e.r data (unexpected code structure)')
def _replacestrings(source):
"""Strip string lookup table (list) and replace values in source."""
match = re.search(r'var *(_\w+)\=\["(.*?)"\];', source, re.DOTALL)
if match:
varname, strings = match.groups()
startpoint = len(match.group(0))
lookup = strings.split('","')
variable = '%s[%%d]' % varname
for index, value in enumerate(lookup):
source = source.replace(variable % index, '"%s"' % value)
return source[startpoint:]
return source
class Unbaser(object):
"""Functor for a given base. Will efficiently convert
strings to natural numbers."""
ALPHABET = {
62: '0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ',
95: (' !"#$%&\'()*+,-./0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ'
'[\]^_`abcdefghijklmnopqrstuvwxyz{|}~')
}
def __init__(self, base):
self.base = base
# If base can be handled by int() builtin, let it do it for us
if 2 <= base <= 36:
self.unbase = lambda string: int(string, base)
else:
if base < 62:
self.ALPHABET[base] = self.ALPHABET[62][0:base]
elif 62 < base < 95:
self.ALPHABET[base] = self.ALPHABET[95][0:base]
# Build conversion dictionary cache
try:
self.dictionary = dict((cipher, index) for index, cipher in enumerate(self.ALPHABET[base]))
except KeyError:
raise TypeError('Unsupported base encoding.')
self.unbase = self._dictunbaser
def __call__(self, string):
return self.unbase(string)
def _dictunbaser(self, string):
"""Decodes a value to an integer."""
ret = 0
for index, cipher in enumerate(string[::-1]):
ret += (self.base ** index) * self.dictionary[cipher]
return ret
class UnpackingError(Exception):
"""Badly packed source or general error. Argument is a
meaningful description."""
pass