Browse Source

Refactoring.

production
Achim D. Brucker 5 years ago
parent
commit
e5d671c7c4
  1. 48
      ExtensionCrawler/crx.py
  2. 8
      crx-tool

48
ExtensionCrawler/crx.py

@ -1,7 +1,7 @@
#!/usr/bin/env python3
#
# Copyright (C) 2016,2017 The University of Sheffield, UK
#
#
# 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
@ -13,20 +13,20 @@
# 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/>.
# along with this program. If not, see <https://www.gnu.org/licenses/>.
#
"""Utility functions for working with Chrome extensionsx archives,
i.e., *.crx files."""
import io
import zipfile
import binascii
from Crypto.PublicKey import RSA
from Crypto.Hash import SHA
from Crypto.Signature import PKCS1_v1_5
import zipfile
import io
class CrxFile:
"""Record class for storing crx files."""
def __init__(self, filename, magic, version, pk_len, sig_len, pk, sig,
header_len, data):
self.file = filename
@ -41,11 +41,12 @@ class CrxFile:
def is_valid_magic(magic):
return (b'Cr24' == magic)
"""Check magic matches the magic bytes of the crx specificaton."""
return magic == b'Cr24'
def is_crxfile(filename):
"Check magic number: crx files should start with \"Cr24\"."
"""Check magic number: crx files should start with \"Cr24\"."""
file = open(filename, 'rb')
magic = file.read(4)
file.close()
@ -53,13 +54,14 @@ def is_crxfile(filename):
def check_signature(pk, sig, data):
"""Check validity of signature contained in the crx file."""
key = RSA.importKey(pk)
hash = SHA.new(data)
return PKCS1_v1_5.new(key).verify(hash, sig)
crxhash = SHA.new(data)
return PKCS1_v1_5.new(key).verify(crxhash, sig)
def read_crx(filename):
"Read header of an crx file (https://developer.chrome.com/extensions/crx)."
"""Read header of an crx file (https://developer.chrome.com/extensions/crx)."""
file = open(filename, 'rb')
magic = file.read(4)
version = int.from_bytes(file.read(4), byteorder='little')
@ -75,6 +77,7 @@ def read_crx(filename):
def print_crx_info(verbose, crx):
"""Print information extracted from a crx file."""
if is_valid_magic(crx.magic):
magic = "valid"
else:
@ -96,15 +99,16 @@ def print_crx_info(verbose, crx):
if verbose:
print("Signature [" + str(crx.sig_len) + "]: " + str(
binascii.hexlify(crx.sig)))
out = f = io.BytesIO(crx.data)
zf = zipfile.ZipFile(out, 'r')
out = io.BytesIO(crx.data)
ziparchive = zipfile.ZipFile(out, 'r')
print("Zip content:")
for info in zf.infolist():
for info in ziparchive.infolist():
print('{:8d} {:8d}'.format(info.file_size, info.compress_size),
info.filename)
def verify_crxfile(verbose, filename):
"""Verify integrity of a crx file."""
if is_crxfile(filename):
if verbose:
print("Found correct magic bytes.")
@ -117,17 +121,21 @@ def verify_crxfile(verbose, filename):
def extract_crxfile(verbose, force, filename, destdir):
"""Extract crxfile into specified destdir."""
crx = read_crx(filename)
if is_valid_magic(crx.magic) | force:
if ("" == destdir) | (destdir is None):
if (destdir == "") | (destdir is None):
destdir = "."
if filename.endswith(".crx"):
dirname = filename[0:len(filename) - 4]
else:
dirname = filename
out = f = io.BytesIO(crx.data)
zf = zipfile.ZipFile(out, 'r')
zf.extractall(destdir + "/" + dirname)
print("Content extracted into: " + destdir + "/" + dirname)
out = io.BytesIO(crx.data)
ziparchive = zipfile.ZipFile(out, 'r')
ziparchive.extractall(destdir + "/" + dirname)
if verbose:
print("Content extracted into: " + destdir + "/" + dirname)
return 0
else:
print("Input file not valid.")
return -1

8
crx-tool

@ -1,7 +1,7 @@
#!/usr/bin/env python3
#
# Copyright (C) 2016 The University of Sheffield, UK
#
#
# 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
@ -15,11 +15,15 @@
# You should have received a copy of the GNU General Public License
# along with this program. If not, see <http://www.gnu.org/licenses/>.
#
""" A tool for analyzing and extracting `*.crx` files
(i.e., Chrome extensions)."""
import argparse
from ExtensionCrawler.crx import *
from ExtensionCrawler.crx import extract_crxfile, verify_crxfile
def main():
"""Main function of the extension crawler."""
parser = argparse.ArgumentParser()
parser.add_argument("file", help="chrome extension archive (*.crx)")
parser.add_argument('targetdir', nargs='?', default="")

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