mirror of
https://github.com/Grasscutters/mitmproxy.git
synced 2024-11-24 00:23:53 +00:00
104 lines
3.2 KiB
Python
104 lines
3.2 KiB
Python
#
|
|
# Unpacker for Dean Edward's p.a.c.k.e.r, a part of javascript beautifier
|
|
# by Einar Lielmanis <einar@jsbeautifier.org>
|
|
#
|
|
# written by Stefano Sanfilippo <a.little.coder@gmail.com>
|
|
#
|
|
# usage:
|
|
#
|
|
# if detect(some_string):
|
|
# unpacked = unpack(some_string)
|
|
#
|
|
|
|
"""Unpacker for Dean Edward's p.a.c.k.e.r"""
|
|
|
|
import re
|
|
from . import UnpackingError
|
|
|
|
PRIORITY = 1
|
|
|
|
def detect(source):
|
|
"""Detects whether `source` is P.A.C.K.E.R. coded."""
|
|
return source.replace(' ', '').startswith('eval(function(p,a,c,k,e,r')
|
|
|
|
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."""
|
|
argsregex = (r"}\('(.*)', *(\d+), *(\d+), *'(.*)'\."
|
|
r"split\('\|'\), *(\d+), *(.*)\)\)")
|
|
args = re.search(argsregex, source, re.DOTALL).groups()
|
|
|
|
try:
|
|
return args[0], args[3].split('|'), int(args[1]), int(args[2])
|
|
except ValueError:
|
|
raise UnpackingError('Corrupted p.a.c.k.e.r. data.')
|
|
|
|
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:
|
|
# 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
|