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various cleanups #62

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various cleanups #62

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3ed4e01
trim trailing whitespace
vapier May 30, 2015
692e6f3
unify settings paths into the one constant
vapier May 30, 2015
5067fe3
make usbkill directly executable
vapier May 30, 2015
b44e0e6
add a proper main() function
vapier May 30, 2015
b8ad368
switch to argparse for command line processing
vapier May 30, 2015
1387b67
use standard python commands for copying settings file
vapier May 30, 2015
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138 changes: 69 additions & 69 deletions usbkill.py
100644 → 100755
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Original file line number Diff line number Diff line change
@@ -1,4 +1,5 @@
# _ _ _ _ _
#!/usr/bin/python
# _ _ _ _ _
# | | | | (_) | |
# _ _ ___| |__ | | _ _| | |
# | | | |/___) _ \| |_/ ) | | |
Expand All @@ -24,7 +25,9 @@

__version__ = "1.0-rc.2"

import argparse
import re
import shutil
import subprocess
import platform
import os, sys, signal
Expand All @@ -43,23 +46,26 @@

# Set the settings filename here
SETTINGS_FILE = '/etc/usbkill/settings.ini'
SETTINGS_DIR = os.path.dirname(SETTINGS_FILE)

help_message = """
__doc__ = """
usbkill is a simple program with one goal: quickly shutdown the computer when a USB is inserted or removed.
Events are logged in /var/log/usbkill/kills.log
You can configure a whitelist of USB ids that are acceptable to insert and the remove.
The USB id can be found by running the command 'lsusb'.
Settings can be changed in /etc/usbkill/settings
Settings can be changed in %(settings)s
In order to be able to shutdown the computer, this program needs to run as root.
"""
""" % {
'settings': SETTINGS_FILE,
}

def log(settings, msg):
log_file = settings['log_file']

contents = '\n{0} {1}\nCurrent state:\n'.format(str(datetime.now()), msg)
with open(log_file, 'a+') as log:
log.write(contents)

# Log current USB state
if CURRENT_PLATFORM.startswith("DARWIN"):
os.system("system_profiler SPUSBDataType >> " + log_file)
Expand All @@ -68,7 +74,7 @@ def log(settings, msg):

def shred(settings):
shredder = settings['remove_file_command']

# List logs and settings to be removed
if settings['melt_usbkill']:
settings['folders_to_remove'].append(os.path.dirname(settings['log_file']))
Expand All @@ -79,32 +85,32 @@ def shred(settings):
else:
settings['files_to_remove'].append(os.path.realpath(__file__))
settings['files_to_remove'].append(usbkill_folder + "/settings.ini")

# Remove files and folders
for _file in settings['files_to_remove'] + settings['folders_to_remove']:
os.system(shredder + _file)

def kill_computer(settings):
# Log what is happening:
if not settings['melt_usbkill']: # No need to spend time on logging if logs will be removed
log(settings, "Detected a USB change. Dumping the list of connected devices and killing the computer...")

# Shred as specified in settings
shred(settings)

if settings['do_sync']:
# Sync the filesystem to save recent changes
os.system("sync")

# Execute kill commands in order.
for command in settings['kill_commands']:
os.system(command)

else:
# If syncing is risky because it might take too long, then sleep for 5ms.
# This will still allow for syncing in most cases.
sleep(0.05)

if settings['shut_down']: # Use argument --no-shut-down to prevent a shutdown.
# Finally poweroff computer immediately
if CURRENT_PLATFORM.startswith("DARWIN"):
Expand All @@ -116,7 +122,7 @@ def kill_computer(settings):
else:
# Linux-based systems - Will shutdown
os.system("poweroff -f")

# Exit the process to prevent executing twice (or more) all commands
sys.exit(0)

Expand All @@ -136,29 +142,29 @@ def check_inside(result, devices):
try:
result["Built-in_Device"]
except KeyError:

# Check if vendor_id/product_id is available for this one
try:
assert "vendor_id" in result and "product_id" in result
# Append to the list of devices
devices.append(DEVICE_RE[1].findall(result["vendor_id"])[0] + ':' + DEVICE_RE[1].findall(result["product_id"])[0])
except AssertionError: {}

# Check if there is items inside
try:
# Looks like, do the while again
for result_deep in result["_items"]:
# Check what's inside the _items array
check_inside(result_deep, devices)

except KeyError: {}

# Run the loop
devices = []
for result in df[0]["_items"]:
check_inside(result, devices)
return devices

def lsusb():
# A Python version of the command 'lsusb' that returns a list of connected usbids
if CURRENT_PLATFORM.startswith("DARWIN"):
Expand All @@ -171,9 +177,9 @@ def lsusb():
def program_present(program):
if sys.version_info[0] == 3:
# Python3
from shutil import which
from shutil import which
return which(program) != None

else:
"""
Test if an executable exist in Python2
Expand All @@ -192,7 +198,7 @@ def is_exe(fpath):
if is_exe(exe_file):
return True
return False

def load_settings(filename):
# Libraries that are only needed in this function:
from json import loads as jsonloads
Expand Down Expand Up @@ -228,7 +234,7 @@ def get_setting(name, gtype=''):

# Read all lines of settings file
config.read(filename)

# Build settings
settings = dict({
'sleep_time' : get_setting('sleep', 'FLOAT'),
Expand All @@ -244,14 +250,14 @@ def get_setting(name, gtype=''):
})

return settings

def loop(settings):
# Main loop that checks every 'sleep_time' seconds if computer should be killed.
# Allows only whitelisted usb devices to connect!
# Does not allow usb device that was present during program start to disconnect!
start_devices = lsusb()
acceptable_devices = set(start_devices + settings['whitelist'])

# Write to logs that loop is starting:
msg = "[INFO] Started patrolling the USB ports every " + str(settings['sleep_time']) + " seconds..."
log(settings, msg)
Expand All @@ -261,7 +267,7 @@ def loop(settings):
while True:
# List the current usb devices
current_devices = lsusb()

# Check that no usbids are connected twice.
# Two devices with same usbid implies a usbid copy attack
if settings['double_usbid_detection'] and not len(current_devices) == len(set(current_devices)):
Expand All @@ -276,10 +282,10 @@ def loop(settings):
for device in start_devices:
if device not in current_devices:
kill_computer(settings)

sleep(settings['sleep_time'])

def startup_checks():
def startup_checks(args):
# Splash
print(" _ _ _ _ _ \n" +
" | | | | (_) | | \n" +
Expand All @@ -288,27 +294,16 @@ def startup_checks():
" | |_| |___ | |_) ) _ (| | | | \n" +
" |____/(___/|____/|_| \_)_|\_)_)\n")

# Check arguments
args = sys.argv[1:]

# Check for help
if '-h' in args or '--help' in args:
sys.exit(help_message)

copy_settings = False
if '--cs' in args:
args.remove('--cs')
copy_settings = True

shut_down = True
if '--no-shut-down' in args:
parser = argparse.ArgumentParser(description=__doc__,
formatter_class=argparse.RawDescriptionHelpFormatter)
parser.add_argument('--cs', dest='copy_settings', default=False, action='store_true',
help='Copy settings to the ini file')
parser.add_argument('--no-shut-down', dest='shut_down', default=True, action='store_false',
help='Run all commands, but do not shut down')
opts = parser.parse_args(args)

if not opts.shut_down:
print("[NOTICE] Ready to execute all the (potentially destructive) commands, but NOT shut down the computer.")
args.remove('--no-shut-down')
shut_down = False

# Check all other args
if len(args) > 0:
sys.exit("\n[ERROR] Argument not understood. Can only understand -h\n")

# Check if program is run as root, else exit.
# Root is needed to power off the computer.
Expand All @@ -323,57 +318,62 @@ def startup_checks():
except subprocess.CalledProcessError:
print("[NOTICE] FileVault is disabled. Sensitive data SHOULD be encrypted.")

if not os.path.isdir("/etc/usbkill/"):
os.mkdir("/etc/usbkill/")
if not os.path.isdir(SETTINGS_DIR):
os.mkdir(SETTINGS_DIR)

# On first time use copy settings.ini to /etc/usebkill/settings.ini
# If dev-mode, always copy and don't remove old settings
if not os.path.isfile(SETTINGS_FILE) or copy_settings:
sources_path = os.path.dirname(os.path.realpath(__file__)) + '/'
if not os.path.isfile(sources_path + "settings.ini"):
sys.exit("\n[ERROR] You have lost your settings file. Get a new copy of the settings.ini and place it in /etc/usbkill/ or in " + sources_path + "/\n")
if not os.path.isfile(SETTINGS_FILE) or opts.copy_settings:
sources_path = os.path.join(os.path.dirname(os.path.realpath(__file__)), 'settings.ini')
if not os.path.isfile(sources_path):
sys.exit("\n[ERROR] You have lost your settings file. "
"Get a new copy of the settings.ini and place it in "
+ SETTINGS_DIR + " or in " + os.path.join(sources_path) + "/\n")
print("[NOTICE] Copying setting.ini to " + SETTINGS_FILE )
os.system("cp " + sources_path + "settings.ini " + SETTINGS_FILE)
if not copy_settings:
os.remove(sources_path + "settings.ini")
shutil.copyfile(sources_path, SETTINGS_FILE)
if not opts.copy_settings:
os.remove(sources_path)

# Load settings
settings = load_settings(SETTINGS_FILE)
settings['shut_down'] = shut_down
settings['shut_down'] = opts.shut_down

# Make sure no spaces a present in paths to be wiped.
for name in settings['folders_to_remove'] + settings['files_to_remove']:
if ' ' in name:
msg += "[ERROR][WARNING] '" + name + "'as specified in your settings.ini contains a space.\n"
sys.exit(msg)

# Make sure srm is present if it will be used.
if settings['melt_usbkill'] or len(settings['folders_to_remove'] + settings['files_to_remove']) > 0:
if not program_present('srm'):
sys.exit("[ERROR] usbkill configured to destroy data, but srm not installed.\n")
if not settings['remove_file_command'].startswith('srm'):
sys.exit("[ERROR] remove_file_command should start with `srm'. srm should be used for automated data overwrite.\n")

# Make sure there is a logging folder
log_folder = os.path.dirname(settings['log_file'])
if not os.path.isdir(log_folder):
os.mkdir(log_folder)

return settings

if __name__=="__main__":
def main(args):
# Run startup checks and load settings
settings = startup_checks()
settings = startup_checks(args)

# Define exit handler now that settings are loaded...
def exit_handler(signum, frame):
print("\n[INFO] Exiting because exit signal was received\n")
log(settings, "[INFO] Exiting because exit signal was received")
sys.exit(0)

# Register handlers for clean exit of program
for sig in [signal.SIGINT, signal.SIGTERM, signal.SIGQUIT, ]:
signal.signal(sig, exit_handler)

# Start main loop
loop(settings)

if __name__=="__main__":
main(sys.argv[1:])