#!/bin/python3
# Dict of file paths with their sha256 checksums
# make sure to run with `--auto-update` flag if you're running first time on this machine
# to automatically update all stored checksums to new values
files = {
'/etc/pam.d/system-auth': '89d62406b2d623a76d53c33aca98ce8ee124ed4a450ff6c8a44cfccca78baa2f',
'/etc/pam.d/su': '7d8962b4a2cd10cf4bc13da8949a4a6151b572d39e87b7125be55f882b16c4da',
'/etc/pam.d/sudo': 'd1738818070684a5d2c9b26224906aad69a4fea77aabd960fc2675aee2df1fa2',
'/etc/passwd': '28d6bec52ac5b4957a2c30dfcd15008dc1a39665c27abce97408489f3dbf02c9',
'/etc/shadow': 'a24f72cba4cbc6b0a8433da2f4b011f31345068e3e5d6bebed6fb6a35769bd59',
'/etc/ssh/sshd_config': '515db2484625122b4254472f7e673649e3d89b57577eaa29395017676735907b',
'/bin/sudo': '0ffaf9e93a080ca1698837729641c283d24500d6cdd2cb4eb8e42427566a230e',
'/bin/su': '3101438405d98e71e9eb68fbc5a33536f1ad0dad5a1c8aacd6da6c95ef082194',
'/usr/bin/passwd': 'd4df1659159737bb4c08a430d493d257d75cdd93e18427946265ae5862a714c7',
'/usr/bin/chsh': '6bc0ae69620dde18f7942e2573afb4a6200b10269612151f48f54ef8423a64fe',
'/usr/bin/chfn': '63178af1347a62f58874640d38d605d3cb1bebe8092533787965ba317e8b553b',
'/home/itsdrike/.ssh/authorized_keys': '674806197893dbf67d3c9ba3abf049d30e571de0c4b450fc9819d3e8b0f854cc',
}
# default state of VERBOSE variable, this is controlled by flag
# `--verbose`, and should probably be kept as false by default
VERBOSE = False
# default state of ENABLE_UPDATE variable, this should be kept to false
# to make sure this script can run as cronjob, not just manually by user
# this variable will get set to True if the script is ran with `--update`
ENABLE_UPDATE = False
# default state of AUTO_UPDATE variable, this has no effect if above is
# False, if not and this variable is True, user input is skipped entirely
# and the checksums are updated automatically, otherwise user confirmation
# is needed, controlled with `--no-confirm`, or `--auto-update`
AUTO_UPDATE = False
# default state of TO_ADD variable, this controls new files, checksums of
# which should be added to the `files` dictionary, this is controlled
# by flag `--add=/path/to/file`
TO_ADD = []
# -----------------------------------------------------------------------------------------------
# - CODE PART, DON'T EDIT UNLESS YOU KNOW WHAT YOU'RE DOING -
# -----------------------------------------------------------------------------------------------
import subprocess
import sys
import os
import re
import colorama
colorama.init(autoreset=True)
def _print_help(prepend_newline=False):
if prepend_newline:
print()
print(
'Accepted flags:\n'
' `-u`/`--update`: If invalid checksum is found, ask user if it should be updated (y/n)\n'
' `-a=path`/`--add=path`: Add a new file to the list of check entries\n'
' `--no-confirm`: Used in combination with `--update`, automatically assumes `y` for all questions\n'
' `--auto-update`: Combines `--update` and `--no-confirm`\n'
' `-e`/`--edit`: Edit this file using your $EDITOR (falls back to vi)\n'
' `-v`/`--verbose`: Verbose mode, show checksums on failures and some more info\n'
' `-h`/`--help`: Show this help'
)
def _yes_no(text, add_yn=True):
if add_yn:
text += ' (y/n): '
while True:
user_inp = input(text).lower()
if user_inp in ('y', 'yes'):
return True
elif user_inp in ('n', 'no'):
return False
def _add_file(file_path, checksum):
this = os.path.abspath(__file__)
pattern = re.compile(r"files = \{\n(\s+)(['\"])(.+\n)+\}")
if file_path in files:
print(
f"{colorama.Fore.RED}Path {colorama.Fore.RESET}"
f"'{colorama.Fore.BLUE}{file_path}{colorama.Fore.RESET}' {colorama.Fore.RED}"
"is already in the 'files' dictionary perhaps you wanted `--update`?"
)
return False
with open(this, 'r') as f:
contents = f.read()
try:
match = list(pattern.finditer(contents))[0]
except IndexError:
raise RuntimeError("Unable to detect files dict with regex, changed dict structure?")
new_line = f"{match[1]}{match[2]}{file_path}{match[2]}: {match[2]}{checksum}{match[2]},\n"
add_position = match.end() - 1 # before bracket symbol
if not match[3].endswith(',\n'):
add_position -= 1 # before newline character on non-comma line
contents = contents[:add_position] + ',' + contents[add_position:]
add_position += 2
new_contents = contents[:add_position] + new_line + contents[add_position:]
try:
with open(this, 'w') as f:
f.write(new_contents)
except PermissionError:
print(
f'{colorama.Fore.RED}PermissionError: {colorama.Fore.RESET}'
'To add a new rule, you must have write access to: '
f"'{colorama.Fore.BLUE}{this}{colorama.Fore.RESET}' (forgot sudo?)"
)
exit(2)
return True
def _update_file(file_path, new_checksum, stored_checksum):
this = os.path.abspath(__file__)
pattern = re.compile(rf"(\s+)(['\"]){file_path}['\"]:(\s+)['\"]{stored_checksum}['\"],?")
with open(this, 'r') as f:
contents = f.read()
new_contents = re.sub(
pattern,
rf'\1\2{file_path}\2:\3\g<2>{new_checksum}\2,',
contents
)
if contents == new_contents: # Line wasn't find, perhaps it's a new file?
return False
try:
with open(this, 'w') as f:
f.write(new_contents)
except PermissionError as e:
print(
f'{colorama.Fore.RED}PermissionError: {colorama.Fore.RESET}'
'To update a rule, you must have write access to: '
f"'{colorama.Fore.BLUE}{this}{colorama.Fore.RESET}' (forgot sudo?)"
)
exit(2)
return True
def _get_checksum(file):
proc = subprocess.run(['sha256sum', file], stdout=subprocess.PIPE, stderr=subprocess.STDOUT)
proc_stdout = proc.stdout.decode('utf-8')
if "No such file or directory" in proc_stdout:
print(
f'{colorama.Fore.RED}File {colorama.Fore.RESET}'
f"'{colorama.Fore.BLUE}{file}{colorama.Fore.RESET}'{colorama.Fore.RED} not found, "
"can't produce sha256 checksum, check the 'files' dictionary on the top of the "
'program and remove this entry.'
)
exit(2)
elif "Permission denied" in proc_stdout:
raise PermissionError(f"PermissionError: Unable to read file '{file}'")
return proc_stdout.replace(f' {file}\n', '')
def _command_exists(command):
proc = subprocess.run(f'which {command}', stdout=subprocess.PIPE, stderr=subprocess.STDOUT, shell=True)
return proc.returncode == 0
def ask_update(file_path):
new_checksum = _get_checksum(file_path)
stored_checksum = files[file_path]
file_line = f"'{colorama.Fore.BLUE}{file_path}{colorama.Fore.RESET}'"
if AUTO_UPDATE or _yes_no(' - ' + file_line + ' update checksum?'):
if AUTO_UPDATE:
print(' - updating checksum for ' + file_line) # path won't get printed by _yes_no(), so print here
result = _update_file(file_path, new_checksum, stored_checksum)
print(f'{colorama.Fore.GREEN} -> Updated')
return result
print(f'{colorama.Fore.RED} -> Staying mismatched')
return False
def run_editor():
try:
editor = os.environ['EDITOR']
except KeyError:
for candidate in ('nvim', 'vim', 'vi', 'emacs', 'nano', 'ne', 'tilde'):
if _command_exists(candidate):
editor = candidate
break
else:
print(f'{colorama.Fore.RED}Unable to find editor software, set {colorama.Fore.YELLOW}$EDITOR')
exit(2)
this = os.path.abspath(__file__)
cmd = f'{editor} {this}'
if not os.access(this, os.W_OK):
if _command_exists('sudo'):
cmd = 'sudo ' + cmd
if VERBOSE:
print(
f'{colorama.Fore.CYAN}'
f'Running editor in escalated mode ({colorama.Fore.YELLOW}sudo{colorama.Fore.CYAN})'
)
elif _command_exists('doas'):
cmd = 'doas ' + cmd
if VERBOSE:
print(
f'{colorama.Fore.CYAN}'
'Running editor in escalated mode ({colorama.Fore.YELLOW}doas{colorama.Fore.CYAN})'
)
else:
if VERBOSE:
print(
f'{colorama.Fore.RED}'
'Running editor non-escalated, sudo/doas unaviable '
f'({colorama.Fore.YELLOW}no write perms){colorama.Fore.RED}'
)
if VERBOSE:
print(f'Starting editor: {colorama.Fore.YELLOW}{cmd}')
return subprocess.run(cmd, shell=True)
def run_check():
not_matched = []
for file, checksum in files.items():
try:
sha256_sum = _get_checksum(file)
except PermissionError as e:
print(
f"Checksum of '{colorama.Fore.BLUE}{file}{colorama.Fore.RESET}': "
f'{colorama.Fore.YELLOW}SKIPPED [PermissionError - no read perms]')
continue
if sha256_sum != checksum:
not_matched.append(file)
print(
f"Checksum of '{colorama.Fore.BLUE}{file}{colorama.Fore.RESET}': "
f'{colorama.Fore.RED}FAIL [Checksum Mismatch]'
)
if VERBOSE:
print(f" -> detected: {colorama.Fore.CYAN}{sha256_sum}")
print(f" -> stored: {colorama.Fore.CYAN}{checksum}")
else:
print(f"Checksum of '{colorama.Fore.BLUE}{file}{colorama.Fore.RESET}': {colorama.Fore.GREEN}OK")
return not_matched
def analyze_args():
# Using globals isn't usually ideal solution,
# but it is the easiest way to handle this
global VERBOSE, ENABLE_UPDATE, AUTO_UPDATE, TO_ADD
try:
args = sys.argv[1:]
except IndexError:
return
for arg in args:
if arg in ('-u', '--update'):
ENABLE_UPDATE = True
elif arg == '--no-confirm':
AUTO_UPDATE = True
elif arg == '--auto-update':
ENABLE_UPDATE = True
AUTO_UPDATE = True
elif '--add=' in arg or '-a=' in arg:
path = arg.replace('--add=', '').replace('-a=', '')
if os.path.exists(path):
TO_ADD.append(path)
else:
print(
f'{colorama.Fore.RED}FileNotFoundError: {colorama.Fore.RESET}'
f"'{colorama.Fore.BLUE}{path}{colorama.Fore.RESET}' -> invalid path"
)
exit(2)
elif arg in ('-v', '--verbose'):
VERBOSE = True
elif arg in ('-e', '--edit'):
run_editor()
exit()
elif arg in ('-h', '--help'):
_print_help()
exit()
else:
print(f'{colorama.Fore.RED}Unrecognized flag: {colorama.Fore.YELLOW}{arg}')
_print_help(prepend_newline=True)
exit(2)
if __name__ == '__main__':
analyze_args()
# if file adding was requested, handle it
if len(TO_ADD) > 0:
for file in TO_ADD:
checksum = _get_checksum(file)
if _add_file(file, checksum):
print(
f"Added '{colorama.Fore.YELLOW}{file}{colorama.Fore.RESET}': "
f"'{colorama.Fore.CYAN}{checksum}{colorama.Fore.RESET}'"
)
exit(0) # when adding files, don't run the check too
# run the actual checksum verifier
not_matched = run_check()
if len(not_matched) > 0 and ENABLE_UPDATE is True:
print(f'\nFiles with mismatched checksums:')
unfixed = not_matched.copy()
for mismatched_file in not_matched:
if ask_update(mismatched_file) is True:
# User did not choose to update the checksum
unfixed.remove(mismatched_file)
if len(unfixed) > 0:
exit(1) # we still have some unfixed mismatched checksums, exit with 1
elif len(not_matched) > 0:
print(f'\nFiles with mismatched checksums:')
for mismatched_file in not_matched:
print(
f'{colorama.Fore.RED} - '
f"{colorama.Fore.RESET}'{colorama.Fore.BLUE}{mismatched_file}{colorama.Fore.RESET}'"
)
exit(1) # exit with error code in case we have changed checksums
else:
print(f'\n{colorama.Fore.GREEN}All checksums are correct')