mac-robber.py

#!/usr/bin/env python
#
# Author:  Jim Clausing
# Date:    2021-06-11
# Version: 1.4
#
# Desc: rewrite of the sleithkit mac-robber in Python
# Unlinke the TSK version, this one can actually includes the MD5 & inode number
# though I still return a 0 in the MD5 column for non-regular files, but calculating
# hashes likely will modify atime, so it is turned off by default
#
# Note: in Python 2.7.x, st_ino, st_dev, st_nlink, st_uid, and st_gid are dummy variables
# on Windows systems. This is apparently fixed in current Python 3 versions.
# On *ALL* systems, os.stat does not return btime, so we put 0 there. :-(
#
# A useful way to use this on a live Linux system is with read-only --bind mounts
#
#   # mount --bind / /mnt
#   # mount -o ro,remount,bind /mnt
#   # ./mac-robber.py -5 -x /mnt/tmp -r /mnt -m system-foo:/ /mnt
#
# This gets us hashes, but because the bind mount is read-only doesn't update atimes
#
# Copyright (c) 2017-2021 AT&T Open Source. All rights reserved.
#

from __future__ import print_function
import os
import sys
import argparse
import hashlib
from stat import *

__version_info__ = (1, 4, 0)
__version__ = ".".join(map(str, __version_info__))


def mode_to_string(mode):
    lookup = ["---", "--x", "-w-", "-wx", "r--", "r-x", "rw-", "rwx"]
    if S_ISDIR(mode):
        mode_str = "d"
    elif S_ISCHR(mode):
        mode_str = "c"
    elif S_ISBLK(mode):
        mode_str = "b"
    elif S_ISREG(mode):
        mode_str = "-"
    elif S_ISFIFO(mode):
        mode_str = "p"
    elif S_ISLNK(mode):
        mode_str = "l"
    elif S_ISSOCK:
        mode_str = "s"
    own_mode = lookup[(mode & 0o700) >> 6]
    if mode & 0o4000:
        if mode & 0o100:
            own_mode = own_mode.replace("x", "s")
        else:
            own_mode = own_mode[:1] + "S"
    mode_str = mode_str + own_mode
    grp_mode = lookup[(mode & 0o70) >> 3]
    if mode & 0o2000:
        if mode & 0o10:
            grp_mode = grp_mode.replace("x", "s")
        else:
            grp_mode = grp_mode[:1] + "S"
    mode_str = mode_str + own_mode
    oth_mode = lookup[(mode & 0o7)]
    if mode & 0o1000:
        if mode & 0o1:
            oth_mode = oth_mode.replace("x", "t")
        else:
            oth_mode = oth_mode[:1] + "T"
    mode_str = mode_str + oth_mode
    return mode_str


def process_item(dirpath, item):
    md5 = hashlib.md5()
    fname = os.path.join(dirpath, item)
    if args.exclude and (fname in args.exclude or dirpath in args.exclude):
        return
    try:
        if os.path.islink(fname):
            status = os.lstat(fname)
        else:
            status = os.stat(fname)
    except IOError:
        return
    except OSError:
        return
    if args.hashes and S_ISREG(status.st_mode):
        try:
            if not (fname.find("/proc/") != -1 and fname.endswith("/kcore")) and status.st_size > 0:
                with open(fname, "rb") as f:
                    if args.size is not None and (status.st_size > args.size):
                        md5str = "0"
                    else:
                        for block in iter(lambda: f.read(65536), b""):
                            md5.update(block)
                        md5str = md5.hexdigest()
            elif status.st_size == 0:
                md5str = "d41d8cd98f00b204e9800998ecf8427e"
            else:
                md5str = "0"
        except IOError:
            md5str = "0"
    else:
        md5str = "0"
    mode = mode_to_string(status.st_mode)
    if os.path.islink(fname) and status.st_size > 0:
        mode = mode + " -> " + os.readlink(fname)
    if sys.version_info < (2, 7, 0):
        mtime = "%14.3f" % (status.st_mtime)
        atime = "%14.3f" % (status.st_atime)
        ctime = "%14.3f" % (status.st_mtime)
    else:
        mtime = "{:14.3f}".format(status.st_mtime)
        atime = "{:14.3f}".format(status.st_atime)
        ctime = "{:14.3f}".format(status.st_mtime)
    btime = 0
    size = status.st_size
    uid = status.st_uid
    gid = status.st_gid
    inode = status.st_ino
    if args.rmprefix:
        if fname.startswith(args.rmprefix):
            fname = fname[len(args.rmprefix) :]
    if args.prefix:
        if fname.find("/") == 0:
            fname = args.prefix + fname
        else:
            fname = args.prefix + "/" + fname
    return (
        md5str
        + "|"
        + fname
        + "|"
        + str(inode)
        + "|"
        + mode
        + "|"
        + str(uid)
        + "|"
        + str(gid)
        + "|"
        + str(size)
        + "|"
        + atime
        + "|"
        + mtime
        + "|"
        + ctime
        + "|"
        + str(btime)
    )


if sys.version_info < (2, 6, 0):
    sys.stderr.write("Not tested on versions earlier than 2.6\n")
    exit(1)

parser = argparse.ArgumentParser(description="collect data on files")
parser.add_argument("directories", metavar="DIR", nargs="+", help="directories to traverse")
parser.add_argument("-m", "--prefix", metavar="PREFIX", help="prefix string")
parser.add_argument(
    "-s", "--size", metavar="SIZE", type=int, help="max size of file to hash, MACB times collected regardless of size"
)
parser.add_argument(
    "-5", "--hashes", action="store_true", help="do MD5 calculation (disabled by default)", default=False
)
parser.add_argument(
    "-x",
    "--exclude",
    metavar="EXCLUDE",
    action="append",
    help="directory trees or files to exclude, does not handle file extensions or regex",
    default=[],
)
parser.add_argument(
    "-r",
    "--rmprefix",
    metavar="RMPREFIX",
    help="prefix to remove, useful when using read-only --bind mount to prevent atime updates",
)
parser.add_argument(
    "-V",
    "--version",
    action="version",
    help="print version number",
    version="%(prog)s v{version}".format(version=__version__),
)

args = parser.parse_args()
if args.size is not None:
    print(args.size)

for directory in args.directories:
    for dirpath, dirs, files in os.walk(directory):
        dirs[:] = [d for d in dirs if d not in args.exclude]
        for directory in dirs:
            outstr = process_item(dirpath, directory)
            if outstr is not None:
                print(outstr)
                sys.stdout.flush()
        for filename in files:
            if filename in args.exclude:
                continue
            outstr = process_item(dirpath, filename)
            if outstr is not None:
                print(outstr)
                sys.stdout.flush()