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picosnitch.py
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picosnitch.py
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#!/usr/bin/env python3
# picosnitch
# Copyright (C) 2020-2023 Eric Lesiuta
# 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
# (at your option) any later version.
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# 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 <https://www.gnu.org/licenses/>.
# https://github.com/elesiuta/picosnitch
import atexit
import collections
import ctypes
import ctypes.util
import curses
import datetime
import fcntl
import functools
import hashlib
import importlib
import importlib.util
import ipaddress
import json
import math
import multiprocessing
import os
import pickle
import pwd
import queue
import resource
import shlex
import shutil
import signal
import site
import socket
import sqlite3
import struct
import subprocess
import sys
import termios
import textwrap
import threading
import time
import typing
# add site dirs for system and user installed packages (to import bcc with picosnitch installed via pipx/venv, or dependencies installed via user)
site.addsitedir("/usr/lib/python3/dist-packages")
site.addsitedir(os.path.expandvars("$PYTHON_USER_SITE"))
import psutil
# picosnitch version and supported platform
VERSION: typing.Final[str] = "1.0.3"
assert sys.version_info >= (3, 8), "Python version >= 3.8 is required"
assert sys.platform.startswith("linux"), "Did not detect a supported operating system"
# warning about -O (optimize) flag since asserts are disabled and some are critical
if sys.flags.optimize > 0:
print("Warning: picosnitch does not function properly with the -O (optimize) flag", file=sys.stderr)
# set constants and RLIMIT_NOFILE if configured
try:
if os.getuid() == 0:
if os.getenv("SUDO_UID"):
home_user = pwd.getpwuid(int(os.getenv("SUDO_UID"))).pw_name
elif os.getenv("SUDO_USER"):
home_user = os.getenv("SUDO_USER")
elif os.getenv("DOAS_USER"):
home_user = os.getenv("DOAS_USER")
else:
for home_user in os.listdir("/home"):
try:
if pwd.getpwnam(home_user).pw_uid >= 1000:
break
except Exception:
pass
home_dir = pwd.getpwnam(home_user).pw_dir
if not os.getenv("SUDO_UID"):
os.environ["SUDO_UID"] = str(pwd.getpwnam(home_user).pw_uid)
if not os.getenv("DBUS_SESSION_BUS_ADDRESS"):
os.environ["DBUS_SESSION_BUS_ADDRESS"] = f"unix:path=/run/user/{pwd.getpwnam(home_user).pw_uid}/bus"
else:
home_dir = os.path.expanduser("~")
if sys.executable.startswith("/snap/"):
home_dir = home_dir.split("/snap/picosnitch")[0]
except Exception:
# fallback if there are no regular users on the system, this will likely be /root
home_dir = os.path.expanduser("~")
BASE_PATH: typing.Final[str] = os.path.join(home_dir, ".config", "picosnitch")
try:
file_path = os.path.join(BASE_PATH, "config.json")
with open(file_path, "r", encoding="utf-8", errors="surrogateescape") as json_file:
nofile = json.load(json_file)["Set RLIMIT_NOFILE"]
if type(nofile) == int:
try:
new_limit = (nofile, resource.getrlimit(resource.RLIMIT_NOFILE)[1])
resource.setrlimit(resource.RLIMIT_NOFILE, new_limit)
time.sleep(0.5)
except Exception as e:
print(type(e).__name__ + str(e.args), file=sys.stderr)
print("Error: Set RLIMIT_NOFILE was found in config.json but it could not be set", file=sys.stderr)
except Exception:
pass
FD_CACHE: typing.Final[int] = resource.getrlimit(resource.RLIMIT_NOFILE)[0] - 128
PID_CACHE: typing.Final[int] = max(8192, 2*FD_CACHE)
st_dev_mask = 0xffffffff
try:
for part in psutil.disk_partitions():
if part.fstype == "btrfs":
st_dev_mask = 0
if not os.path.exists(os.path.join(BASE_PATH, "config.json")):
# only warn users about btrfs on first run (by checking for config.json)
print("Warning: running picosnitch on systems with btrfs is not fully supported due to dev number strangeness and non-unique inodes (this is still fine for most use cases)", file=sys.stderr)
break
file_path = os.path.join(BASE_PATH, "config.json")
with open(file_path, "r", encoding="utf-8", errors="surrogateescape") as json_file:
set_mask = json.load(json_file)["Set st_dev mask"]
if type(set_mask) == int:
st_dev_mask = set_mask
except Exception:
pass
ST_DEV_MASK: typing.Final[int] = st_dev_mask
### classes
class Daemon:
"""A generic daemon class based on http://www.jejik.com/files/examples/daemon3x.py"""
def __init__(self, pidfile):
self.pidfile = pidfile
def daemonize(self):
"""Daemonize class. UNIX double fork mechanism."""
try:
pid = os.fork()
if pid > 0:
# exit first parent
sys.exit(0)
except OSError as err:
sys.stderr.write('fork #1 failed: {0}\n'.format(err))
sys.exit(1)
# decouple from parent environment
os.chdir('/')
os.setsid()
os.umask(0)
# do second fork
try:
pid = os.fork()
if pid > 0:
# exit from second parent
sys.exit(0)
except OSError as err:
sys.stderr.write('fork #2 failed: {0}\n'.format(err))
sys.exit(1)
# redirect standard file descriptors
sys.stdout.flush()
sys.stderr.flush()
si = open(os.devnull, 'r')
so = open(os.devnull, 'a+')
se = open(os.devnull, 'a+')
os.dup2(si.fileno(), sys.stdin.fileno())
os.dup2(so.fileno(), sys.stdout.fileno())
os.dup2(se.fileno(), sys.stderr.fileno())
# write pidfile
atexit.register(self.delpid)
pid = str(os.getpid())
with open(self.pidfile,'w+') as f:
f.write(pid + '\n')
def delpid(self):
os.remove(self.pidfile)
def getpid(self):
"""Get the pid from the pidfile"""
try:
with open(self.pidfile, "r") as f:
pid = int(f.read().strip())
except IOError:
pid = None
return pid
def start(self):
"""Start the daemon."""
# Check for a pidfile to see if the daemon already runs
pid = self.getpid()
if pid:
message = "pidfile {0} already exist. " + \
"picosnitch already running?\n"
sys.stderr.write(message.format(self.pidfile))
sys.exit(1)
# Start the daemon
self.daemonize()
self.run()
def stop(self):
"""Stop the daemon."""
pid = self.getpid()
if not pid:
message = "pidfile {0} does not exist. " + \
"picosnitch not running?\n"
sys.stderr.write(message.format(self.pidfile))
return # not an error in a restart
# Try killing the daemon process
try:
while 1:
os.kill(pid, signal.SIGTERM)
time.sleep(0.1)
except OSError as err:
e = str(err.args)
if e.find("No such process") > 0:
if os.path.exists(self.pidfile):
os.remove(self.pidfile)
else:
print (str(err.args))
sys.exit(1)
def restart(self):
"""Restart the daemon."""
self.stop()
self.start()
def status(self):
"""Get daemon status."""
pid = self.getpid()
if pid:
try:
with open(f"/proc/{pid}/cmdline", "r") as f:
cmdline = f.read()
except Exception:
cmdline = ""
if "picosnitch" in cmdline:
print(f"picosnitch is currently running with pid {pid}.")
else:
print("pidfile exists however picosnitch was not detected.")
else:
print("picosnitch does not appear to be running.")
def run(self):
"""Subclass Daemon and override this method"""
class ProcessManager:
"""A class for managing a subprocess"""
def __init__(self, name: str, target: typing.Callable, init_args: tuple = ()) -> None:
self.name, self.target, self.init_args = name, target, init_args
self.q_in, self.q_out = multiprocessing.Queue(), multiprocessing.Queue()
self.start()
def start(self) -> None:
self.p = multiprocessing.Process(name=self.name, target=self.target, daemon=True,
args=(*self.init_args, self.q_in, self.q_out)
)
self.p.start()
self.pp = psutil.Process(self.p.pid)
def terminate(self) -> None:
if self.p.is_alive():
self.p.terminate()
self.p.join(timeout=5)
if self.p.is_alive():
self.p.kill()
self.p.join(timeout=5)
self.p.close()
def is_alive(self) -> bool:
return self.p.is_alive()
def is_zombie(self) -> bool:
return self.pp.is_running() and self.pp.status() == psutil.STATUS_ZOMBIE
def memory(self) -> int:
return self.pp.memory_info().rss
class NotificationManager:
"""A singleton for creating system tray notifications, holds notifications in queue if fails, prints if disabled"""
__instance = None
dbus_notifications = False
notifications_ready = False
notification_queue = []
last_notification = ""
def __new__(cls, *args, **kwargs):
if not cls.__instance:
cls.__instance = super(NotificationManager, cls).__new__(cls, *args, **kwargs)
return cls.__instance
def enable_notifications(self):
self.dbus_notifications = True
try:
import dbus
os.seteuid(int(os.getenv("SUDO_UID")))
dbus_session_obj = dbus.SessionBus().get_object("org.freedesktop.Notifications", "/org/freedesktop/Notifications")
interface = dbus.Interface(dbus_session_obj, "org.freedesktop.Notifications")
self.system_notification = lambda msg: interface.Notify("picosnitch", 0, "", "picosnitch", msg, [], [], 2000)
self.notifications_ready = True
except Exception:
pass
finally:
os.seteuid(os.getuid())
def toast(self, msg: str, file=sys.stdout) -> None:
try:
if self.notifications_ready:
if self.last_notification != msg:
self.last_notification = msg
self.system_notification(msg)
else:
print(msg, file=file)
self.notification_queue.append(msg)
if self.dbus_notifications:
self.enable_notifications()
if self.notifications_ready:
for msg in self.notification_queue:
try:
if self.last_notification != msg:
self.last_notification = msg
self.system_notification(msg)
except Exception:
pass
self.notification_queue = []
except Exception:
self.notification_queue.append(msg)
self.notifications_ready = False
class BpfEvent(typing.TypedDict):
"""Process and connection data for each event captured by the BPF program, and sent to the main & secondary processes"""
pid: int
name: str
fd: int
dev: int
ino: int
exe: str
cmdline: str
ppid: int
pname: str
pfd: int
pdev: int
pino: int
pexe: str
pcmdline: str
uid: int
send: int
recv: int
lport: int
rport: int
laddr: str
raddr: str
___domain: str
class FanotifyEventMetadata(ctypes.Structure):
"""https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/include/uapi/linux/fanotify.h"""
_fields_ = [
("event_len", ctypes.c_uint32),
("vers", ctypes.c_uint8),
("reserved", ctypes.c_uint8),
("metadata_len", ctypes.c_uint16),
("mask", ctypes.c_uint64),
("fd", ctypes.c_int32),
("pid", ctypes.c_int32)
]
### functions
def read_snitch() -> dict:
"""read data for the snitch dictionary from config.json and record.json or init new files if not found"""
template = {
"Config": {
"DB retention (days)": 30,
"DB sql log": True,
"DB sql server": {},
"DB text log": False,
"DB write limit (seconds)": 10,
"Dash scroll zoom": True,
"Dash theme": "",
"Desktop notifications": True,
"Every exe (not just conns)": False,
"GeoIP lookup": True,
"Log addresses": True,
"Log commands": True,
"Log ignore": [],
"Log ports": True,
"Perf ring buffer (pages)": 256,
"Set RLIMIT_NOFILE": None,
"Set st_dev mask": None,
"VT API key": "",
"VT file upload": False,
"VT request limit (seconds)": 15
},
"Error Log": [],
"Exe Log": [],
"Executables": {},
"Names": {},
"Parent Executables": {},
"Parent Names": {},
"SHA256": {}
}
data = {k: v for k, v in template.items()}
data["Config"] = {k: v for k, v in template["Config"].items()}
write_config = False
config_path = os.path.join(BASE_PATH, "config.json")
record_path = os.path.join(BASE_PATH, "record.json")
if os.path.exists(config_path):
with open(config_path, "r", encoding="utf-8", errors="surrogateescape") as json_file:
data["Config"] = json.load(json_file)
for key in template["Config"]:
if key not in data["Config"]:
data["Config"][key] = template["Config"][key]
write_config = True
else:
write_config = True
if os.path.exists(record_path):
with open(record_path, "r", encoding="utf-8", errors="surrogateescape") as json_file:
snitch_record = json.load(json_file)
for key in ["Executables", "Names", "Parent Executables", "Parent Names", "SHA256"]:
if key in snitch_record:
data[key] = snitch_record[key]
assert all(type(data[key]) == type(template[key]) for key in template), "Invalid json files"
assert all(key in ["Set RLIMIT_NOFILE", "Set st_dev mask"] or type(data["Config"][key]) == type(template["Config"][key]) for key in template["Config"]), "Invalid config"
if write_config:
write_snitch(data, write_config=True)
return data
def write_snitch(snitch: dict, write_config: bool = False, write_record: bool = True) -> None:
"""write the snitch dictionary to config.json, record.json, exe.log, and error.log"""
config_path = os.path.join(BASE_PATH, "config.json")
record_path = os.path.join(BASE_PATH, "record.json")
exe_log_path = os.path.join(BASE_PATH, "exe.log")
error_log_path = os.path.join(BASE_PATH, "error.log")
assert os.getuid() == 0, "Requires root privileges to write config and log files"
if not os.path.isdir(BASE_PATH):
os.makedirs(BASE_PATH)
if os.stat(BASE_PATH).st_uid == 0 and os.getenv("SUDO_UID"):
os.chown(BASE_PATH, int(os.getenv("SUDO_UID")), int(os.getenv("SUDO_UID")))
snitch_config = snitch["Config"]
try:
if write_config:
with open(config_path, "w", encoding="utf-8", errors="surrogateescape") as json_file:
json.dump(snitch_config, json_file, indent=2, separators=(',', ': '), sort_keys=True, ensure_ascii=False)
del snitch["Config"]
if snitch["Error Log"]:
with open(error_log_path, "a", encoding="utf-8", errors="surrogateescape") as text_file:
text_file.write("\n".join(snitch["Error Log"]) + "\n")
del snitch["Error Log"]
if snitch["Exe Log"]:
with open(exe_log_path, "a", encoding="utf-8", errors="surrogateescape") as text_file:
text_file.write("\n".join(snitch["Exe Log"]) + "\n")
del snitch["Exe Log"]
if write_record:
with open(record_path, "w", encoding="utf-8", errors="surrogateescape") as json_file:
json.dump(snitch, json_file, indent=2, separators=(',', ': '), sort_keys=True, ensure_ascii=False)
except Exception:
NotificationManager().toast("picosnitch write error", file=sys.stderr)
snitch["Config"] = snitch_config
snitch["Error Log"] = []
snitch["Exe Log"] = []
@functools.lru_cache(maxsize=None)
def reverse_dns_lookup(ip: str) -> str:
"""do a reverse dns lookup, return original ip if fails"""
try:
host = socket.getnameinfo((ip, 0), 0)[0]
try:
_ = ipaddress.ip_address(host)
return ip
except ValueError:
return ".".join(reversed(host.split(".")))
except Exception:
return ip
@functools.lru_cache(maxsize=PID_CACHE)
def get_sha256_fd(path: str, st_dev: int, st_ino: int, _mod_cnt: int) -> str:
"""get sha256 of process executable from /proc/monitor_pid/fd/proc_exe_fd"""
try:
sha256 = hashlib.sha256()
with open(path, "rb") as f:
if not st_ino:
return "!!! FD Stat Error"
if (st_dev, st_ino) != get_fstat(f.fileno()):
return "!!! FD Cache Error"
while data := f.read(1048576):
sha256.update(data)
return sha256.hexdigest()
except Exception:
return "!!! FD Read Error"
@functools.lru_cache(maxsize=PID_CACHE)
def get_sha256_pid(pid: int, st_dev: int, st_ino: int) -> str:
"""get sha256 of process executable from /proc/pid/exe"""
try:
sha256 = hashlib.sha256()
with open(f"/proc/{pid}/exe", "rb") as f:
if (st_dev, st_ino) != get_fstat(f.fileno()):
return "!!! PID Recycled Error"
while data := f.read(1048576):
sha256.update(data)
return sha256.hexdigest()
except Exception:
return "!!! PID Read Error"
@functools.lru_cache(maxsize=PID_CACHE)
def get_sha256_fuse(q_in: multiprocessing.Queue, q_out: multiprocessing.Queue, path: str, pid: int, st_dev: int, st_ino: int, _mod_cnt: int) -> str:
"""get sha256 of process executable from a fuse mount"""
q_in.put(pickle.dumps((path, pid, st_dev, st_ino)))
try:
return q_out.get()
except Exception:
return "!!! FUSE Subprocess Error"
def get_fstat(fd: int) -> typing.Tuple[int, int]:
"""get (st_dev, st_ino) or (0, 0) if fails"""
try:
stat = os.fstat(fd)
return stat.st_dev & ST_DEV_MASK, stat.st_ino
except Exception:
return 0, 0
def get_fanotify_events(fan_fd: int, fan_mod_cnt: dict, q_error: multiprocessing.Queue) -> None:
"""check if any watched executables were modified and increase count to trigger rehash"""
sizeof_event = ctypes.sizeof(FanotifyEventMetadata)
bytes_avail = ctypes.c_int()
fcntl.ioctl(fan_fd, termios.FIONREAD, bytes_avail)
for i in range(0, bytes_avail.value, sizeof_event):
try:
fanotify_event_metadata = FanotifyEventMetadata()
buf = os.read(fan_fd, sizeof_event)
ctypes.memmove(ctypes.addressof(fanotify_event_metadata), buf, sizeof_event)
st_dev, st_ino = get_fstat(fanotify_event_metadata.fd)
fan_mod_cnt[f"{st_dev} {st_ino}"] += 1
os.close(fanotify_event_metadata.fd)
except Exception as e:
q_error.put("Fanotify Event %s%s on line %s" % (type(e).__name__, str(e.args), sys.exc_info()[2].tb_lineno))
def get_vt_results(snitch: dict, q_vt: multiprocessing.Queue, q_out: multiprocessing.Queue, check_pending: bool = False) -> None:
"""get virustotal results from subprocess and update snitch, q_vt = q_in if check_pending else q_out"""
if check_pending:
for exe in snitch["SHA256"]:
for sha256 in snitch["SHA256"][exe]:
if snitch["SHA256"][exe][sha256] in ["VT Pending", "File not analyzed (no api key)", "", None]:
if exe in snitch["Executables"] and snitch["Executables"][exe]:
name = snitch["Executables"][exe][0]
elif exe in snitch["Parent Executables"] and snitch["Parent Executables"][exe]:
name = snitch["Parent Executables"][exe][0]
else:
name = exe
proc = {"exe": exe, "name": name}
q_vt.put(pickle.dumps((proc, sha256)))
else:
while not q_vt.empty():
proc, sha256, result, suspicious = pickle.loads(q_vt.get())
q_out.put(pickle.dumps({"type": "vt_result", "name": proc["name"], "exe": proc["exe"], "sha256": sha256, "result": result, "suspicious": suspicious}))
def monitor_subprocess_initial_poll() -> list:
"""poll initial processes and connections using psutil"""
initial_processes = []
for pid in psutil.pids():
try:
proc = psutil.Process(pid).as_dict(attrs=["name", "exe", "pid", "ppid", "uids"], ad_value="")
proc["uid"] = proc["uids"][0]
proc["pname"] = psutil.Process(proc["ppid"]).name()
proc["raddr"] = ""
proc["rport"] = -1
proc["laddr"] = ""
proc["lport"] = -1
initial_processes.append(proc)
except Exception:
pass
for conn in psutil.net_connections(kind="all"):
try:
proc = psutil.Process(conn.pid).as_dict(attrs=["name", "exe", "pid", "ppid", "uids"], ad_value="")
proc["uid"] = proc["uids"][0]
proc["pname"] = psutil.Process(proc["ppid"]).name()
proc["raddr"] = conn.raddr.ip
proc["rport"] = conn.raddr.port
proc["laddr"] = conn.laddr.ip
proc["lport"] = conn.laddr.port
initial_processes.append(proc)
except Exception:
pass
return initial_processes
def secondary_subprocess_sha_wrapper(snitch: dict, fan_mod_cnt: dict, proc: dict, p_rfuse: ProcessManager, q_vt: multiprocessing.Queue, q_out: multiprocessing.Queue, q_error: multiprocessing.Queue) -> str:
"""get sha256 of executable and submit to primary_subprocess or virustotal_subprocess if necessary"""
sha_fd_error = ""
sha_pid_error = ""
sha256 = get_sha256_fd(proc["fd"], proc["dev"], proc["ino"], fan_mod_cnt["%d %d" % (proc["dev"], proc["ino"])])
if sha256.startswith("!"):
# fallback on trying to read directly (if still alive) if fd_cache fails, probable causes include:
# system suspends in the middle of hashing (since cache is reset)
# process too short lived to open fd or stat in time (then fallback will fail too)
# too many executables on system (see Set RLIMIT_NOFILE)
sha_fd_error = sha256
sha256 = get_sha256_pid(proc["pid"], proc["dev"], proc["ino"])
if sha256.startswith("!"):
# fallback to trying to read from fuse mount
# this is meant for appimages that are run as the same user as the one running picosnitch, since they are not readable as root
sha_pid_error = sha256
sha256 = get_sha256_fuse(p_rfuse.q_in, p_rfuse.q_out, proc["fd"], proc["pid"], proc["dev"], proc["ino"], fan_mod_cnt["%d %d" % (proc["dev"], proc["ino"])])
if sha256.startswith("!"):
# notify user with what went wrong (may be cause for suspicion)
sha256_error = sha_fd_error[4:] + " and " + sha_pid_error[4:] + " and " + sha256[4:]
sha256 = sha_fd_error + " " + sha_pid_error + " " + sha256
q_error.put(sha256_error + " for " + str(proc))
elif proc["exe"] not in snitch["SHA256"] or sha256 not in snitch["SHA256"][proc["exe"]]:
q_error.put("Fallback to FUSE hash successful on " + sha_fd_error[4:] + " and " + sha_pid_error[4:] + " for " + str(proc))
elif proc["exe"] not in snitch["SHA256"] or sha256 not in snitch["SHA256"][proc["exe"]]:
q_error.put("Fallback to PID hash successful on " + sha_fd_error[4:] + " for " + str(proc))
if proc["exe"] in snitch["SHA256"]:
if sha256 not in snitch["SHA256"][proc["exe"]]:
snitch["SHA256"][proc["exe"]][sha256] = "SUBMITTED"
q_vt.put(pickle.dumps((proc, sha256)))
q_out.put(pickle.dumps({"type": "sha256", "name": proc["name"], "exe": proc["exe"], "sha256": sha256}))
elif snitch["SHA256"][proc["exe"]][sha256] == "Failed to read process for upload":
snitch["SHA256"][proc["exe"]][sha256] = "RETRY"
q_vt.put(pickle.dumps((proc, sha256)))
else:
snitch["SHA256"][proc["exe"]] = {sha256: "SUBMITTED"}
q_vt.put(pickle.dumps((proc, sha256)))
q_out.put(pickle.dumps({"type": "sha256", "name": proc["name"], "exe": proc["exe"], "sha256": sha256}))
return sha256
def secondary_subprocess_helper(snitch: dict, fan_mod_cnt: dict, new_processes: typing.List[bytes], p_rfuse: ProcessManager, q_vt: multiprocessing.Queue, q_out: multiprocessing.Queue, q_error: multiprocessing.Queue) -> typing.List[tuple]:
"""iterate over the list of process/connection data to generate a list of entries for the sql database"""
datetime_now = time.strftime("%Y-%m-%d %H:%M:%S")
traffic_counter = collections.defaultdict(int)
transaction = set()
for proc_pickle in new_processes:
proc: BpfEvent = pickle.loads(proc_pickle)
if type(proc) != dict:
q_error.put("sync error between secondary and primary, received '%s' in middle of transfer" % str(proc))
continue
# get the sha256 of the process executable and its parent
sha256 = secondary_subprocess_sha_wrapper(snitch, fan_mod_cnt, proc, p_rfuse, q_vt, q_out, q_error)
pproc = {"pid": proc["ppid"], "name": proc["pname"], "exe": proc["pexe"], "fd": proc["pfd"], "dev": proc["pdev"], "ino": proc["pino"]}
psha256 = secondary_subprocess_sha_wrapper(snitch, fan_mod_cnt, pproc, p_rfuse, q_vt, q_out, q_error)
# join or omit commands from logs
if snitch["Config"]["Log commands"]:
proc["cmdline"] = shlex.join(proc["cmdline"].encode("utf-8", "ignore").decode("utf-8", "ignore").strip("\0\t\n ").split("\0"))
proc["pcmdline"] = shlex.join(proc["pcmdline"].encode("utf-8", "ignore").decode("utf-8", "ignore").strip("\0\t\n ").split("\0"))
else:
proc["cmdline"] = ""
proc["pcmdline"] = ""
# reverse dns lookup or omit with IP from logs
if snitch["Config"]["Log addresses"]:
if not proc["___domain"]:
proc["___domain"] = reverse_dns_lookup(proc["raddr"])
else:
proc["___domain"], proc["raddr"] = "", ""
if not snitch["Config"]["Log ports"]:
proc["lport"] = min(0, proc["lport"])
proc["rport"] = min(0, proc["rport"])
# omit entry from logs
ignored = False
for ignore in snitch["Config"]["Log ignore"]:
if ((proc["rport"] == ignore) or
(proc["lport"] == ignore) or
(sha256 == ignore) or
(type(ignore) == str and proc["___domain"].startswith(ignore))
):
ignored = True
break
if ignored:
continue
if snitch["Config"]["Log ignore IP"] and proc["raddr"]:
raddr = ipaddress.ip_address(proc["raddr"])
if (any(raddr in network for network in snitch["Config"]["Log ignore IP"])):
continue
laddr = ipaddress.ip_address(proc["laddr"])
if (any(laddr in network for network in snitch["Config"]["Log ignore IP"])):
continue
# create sql entry
event = (proc["exe"], proc["name"], proc["cmdline"], sha256, proc["pexe"], proc["pname"], proc["pcmdline"], psha256, proc["uid"], proc["lport"], proc["rport"], proc["laddr"], proc["raddr"], proc["___domain"])
traffic_counter["send " + str(event)] += proc["send"]
traffic_counter["recv " + str(event)] += proc["recv"]
transaction.add(event)
return [(datetime_now, traffic_counter["send " + str(event)], traffic_counter["recv " + str(event)], *event) for event in transaction]
def primary_subprocess_helper(snitch: dict, new_processes: typing.List[bytes]) -> None:
"""iterate over the list of process/connection data to update the snitch dictionary and create notifications on new entries"""
datetime_now = time.strftime("%Y-%m-%d %H:%M:%S")
for proc_pickle in new_processes:
proc: BpfEvent = pickle.loads(proc_pickle)
proc_name, proc_exe, snitch_names, snitch_executables, parent = proc["name"], proc["exe"], snitch["Names"], snitch["Executables"], ""
for i in range(2):
notification = []
if proc_name in snitch_names:
if proc_exe not in snitch_names[proc_name]:
snitch_names[proc_name].append(proc_exe)
else:
snitch_names[proc_name] = [proc_exe]
notification.append("name")
if proc_exe in snitch_executables:
if proc_name not in snitch_executables[proc_exe]:
snitch_executables[proc_exe].append(proc_name)
else:
snitch_executables[proc_exe] = [proc_name]
notification.append("exe")
if proc_exe not in snitch["SHA256"]:
snitch["SHA256"][proc_exe] = {}
if notification:
snitch["Exe Log"].append(f"{datetime_now} {proc_name:<16.16} {proc_exe} (new {', '.join(notification)}){parent}")
NotificationManager().toast(f"picosnitch: {proc_name} {proc_exe}")
proc_name, proc_exe, snitch_names, snitch_executables, parent = proc["pname"], proc["pexe"], snitch["Parent Names"], snitch["Parent Executables"], " (parent)"
### processes
def primary_subprocess(snitch, snitch_pipes, secondary_pipe, q_error, q_in, _q_out):
"""first to receive connection data from monitor, more responsive than secondary, creates notifications and writes exe.log, error.log, and record.json"""
try:
os.nice(-20)
except Exception:
pass
# init variables for loop
parent_process = multiprocessing.parent_process()
snitch_record = pickle.dumps([snitch["Executables"], snitch["Names"], snitch["Parent Executables"], snitch["Parent Names"], snitch["SHA256"]])
last_write = 0
write_record = False
processes_to_send = []
# init notifications
if snitch["Config"]["Desktop notifications"]:
NotificationManager().enable_notifications()
# init signal handlers
def write_snitch_and_exit(snitch: dict, q_error: multiprocessing.Queue, snitch_pipes):
while not q_error.empty():
error = q_error.get()
snitch["Error Log"].append(time.strftime("%Y-%m-%d %H:%M:%S") + " " + error)
# shorten some common error messages before displaying them and after writing them to error.log
error = error.replace("FD Read Error and PID Read Error and FUSE Read Error for", "Read Error for")
if len(error) > 50:
error = error[:47] + "..."
NotificationManager().toast(error, file=sys.stderr)
write_snitch(snitch)
for snitch_pipe in snitch_pipes:
snitch_pipe.close()
sys.exit(0)
signal.signal(signal.SIGTERM, lambda *args: write_snitch_and_exit(snitch, q_error, snitch_pipes))
signal.signal(signal.SIGINT, lambda *args: write_snitch_and_exit(snitch, q_error, snitch_pipes))
# init thread to receive new connection data over pipe
def snitch_pipe_thread(snitch_pipes, pipe_data: list, listen: threading.Event, ready: threading.Event):
while True:
listen.wait()
new_processes = pipe_data[0]
while listen.is_set():
for i in range(5):
if any(snitch_pipe.poll() for snitch_pipe in snitch_pipes):
break
time.sleep(1)
for snitch_pipe in snitch_pipes:
while snitch_pipe.poll():
new_processes.append(snitch_pipe.recv_bytes())
ready.set()
listen, ready = threading.Event(), threading.Event()
pipe_data = [[]]
thread = threading.Thread(target=snitch_pipe_thread, args=(snitch_pipes, pipe_data, listen, ready,), daemon=True)
thread.start()
listen.set()
# main loop
while True:
if not parent_process.is_alive():
q_error.put("picosnitch has stopped")
write_snitch_and_exit(snitch, q_error, snitch_pipes)
try:
# check for errors
while not q_error.empty():
error = q_error.get()
snitch["Error Log"].append(time.strftime("%Y-%m-%d %H:%M:%S") + " " + error)
# shorten some common error messages before displaying them and after writing them to error.log
error = error.replace("FD Read Error and PID Read Error and FUSE Read Error for", "Read Error for")
if len(error) > 50:
error = error[:47] + "..."
# don't need to toast fallback success messages
if error.startswith("Fallback to FUSE hash successful on ") or error.startswith("Fallback to PID hash successful on "):
continue
NotificationManager().toast(error, file=sys.stderr)
# get list of new processes and connections since last update
listen.clear()
if not ready.wait(timeout=300):
q_error.put("thread timeout error for primary subprocess")
write_snitch_and_exit(snitch, q_error, snitch_pipes)
new_processes = pipe_data[0]
pipe_data[0] = []
ready.clear()
listen.set()
# process the list and update snitch, send new process/connection data to secondary subprocess if ready
primary_subprocess_helper(snitch, new_processes)
processes_to_send += new_processes
while not q_in.empty():
msg: dict = pickle.loads(q_in.get())
if msg["type"] == "ready":
secondary_pipe.send_bytes(pickle.dumps(len(processes_to_send)))
for proc_pickle in processes_to_send:
secondary_pipe.send_bytes(proc_pickle)
secondary_pipe.send_bytes(pickle.dumps("done"))
processes_to_send = []
break
elif msg["type"] == "sha256":
if msg["exe"] in snitch["SHA256"]:
if msg["sha256"] not in snitch["SHA256"][msg["exe"]]:
snitch["SHA256"][msg["exe"]][msg["sha256"]] = "VT Pending"
snitch["Exe Log"].append(f"{time.strftime('%Y-%m-%d %H:%M:%S')} {msg['sha256']:<16.16} {msg['exe']} (new hash)")
NotificationManager().toast(f"New sha256: {msg['exe']}")
else:
snitch["SHA256"][msg["exe"]] = {msg["sha256"]: "VT Pending"}
elif msg["type"] == "vt_result":
if msg["exe"] in snitch["SHA256"]:
if msg["sha256"] not in snitch["SHA256"][msg["exe"]]:
snitch["Exe Log"].append(f"{time.strftime('%Y-%m-%d %H:%M:%S')} {msg['sha256']:<16.16} {msg['exe']} (new hash)")
NotificationManager().toast(f"New sha256: {msg['exe']}")
snitch["SHA256"][msg["exe"]][msg["sha256"]] = msg["result"]
else:
snitch["SHA256"][msg["exe"]] = {msg["sha256"]: msg["result"]}
if msg["suspicious"]:
snitch["Exe Log"].append(f"{time.strftime('%Y-%m-%d %H:%M:%S')} {msg['sha256']:<16.16} {msg['exe']} (suspicious)")
NotificationManager().toast(f"Suspicious VT results: {msg['exe']}")
else:
snitch["Exe Log"].append(f"{time.strftime('%Y-%m-%d %H:%M:%S')} {msg['sha256']:<16.16} {msg['exe']} (clean)")
# write the snitch dictionary to record.json, error.log, and exe.log (limit writes to reduce disk wear)
if snitch["Error Log"] or snitch["Exe Log"] or time.time() - last_write > 30:
new_record = pickle.dumps([snitch["Executables"], snitch["Names"], snitch["Parent Executables"], snitch["Parent Names"], snitch["SHA256"]])
if new_record != snitch_record:
snitch_record = new_record
write_record = True
write_snitch(snitch, write_record=write_record)
last_write = time.time()
write_record = False
except Exception as e:
q_error.put("primary subprocess %s%s on line %s" % (type(e).__name__, str(e.args), sys.exc_info()[2].tb_lineno))
def secondary_subprocess(snitch, fan_fd, p_rfuse: ProcessManager, p_virustotal: ProcessManager, secondary_pipe, q_primary_in, q_error, _q_in, _q_out):
"""second to receive connection data from monitor, less responsive than primary, coordinates connection data with virustotal subprocess and checks fanotify, updates connection logs and reports sha256/vt_results back to primary_subprocess if needed"""
parent_process = multiprocessing.parent_process()
# maintain a separate copy of the snitch dictionary here and coordinate with the primary_subprocess (sha256 and vt_results)
get_vt_results(snitch, p_virustotal.q_in, q_primary_in, True)
# init sql
# (contime text, send integer, recv integer, exe text, name text, cmdline text, sha256 text, pexe text, pname text, pcmdline text, psha256 text, uid integer, lport integer, rport integer, laddr text, raddr text, ___domain text)
# (datetime_now, traffic_counter["send " + str(event)], traffic_counter["recv " + str(event)], *(proc["exe"], proc["name"], proc["cmdline"], sha256, proc["pexe"], proc["pname"], proc["pcmdline"], psha256, proc["uid"], proc["lport"], proc["rport"], proc["laddr"], proc["raddr"], proc["___domain"]))
sqlite_query = ''' INSERT INTO connections VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?) '''
file_path = os.path.join(BASE_PATH, "snitch.db")
text_path = os.path.join(BASE_PATH, "conn.log")
if snitch["Config"]["DB sql log"]:
con = sqlite3.connect(file_path)
cur = con.cursor()
cur.execute(''' PRAGMA user_version ''')
assert cur.fetchone()[0] == 3, f"Incorrect database version of snitch.db for picosnitch v{VERSION}"
cur.execute(''' DELETE FROM connections WHERE contime < datetime("now", "localtime", "-%d days") ''' % int(snitch["Config"]["DB retention (days)"]))
con.commit()
con.close()
if sql_kwargs := snitch["Config"]["DB sql server"]:
sql_client = sql_kwargs.pop("client", "no client error")
table_name = sql_kwargs.pop("table_name", "connections")
sql = importlib.import_module(sql_client)
sql_query = sqlite_query.replace("?", "%s").replace("connections", table_name)
log_destinations = int(bool(snitch["Config"]["DB sql log"])) + int(bool(sql_kwargs)) + int(bool(snitch["Config"]["DB text log"]))
# init fanotify mod counter = {"st_dev st_ino": modify_count}, and traffic counter = {"send|recv pid socket_ino": bytes}
fan_mod_cnt = collections.defaultdict(int)
# get network address and mask for ignored IP subnets
ignored_ips = []
for ip_subnet in reversed(snitch["Config"]["Log ignore"]):
try:
ignored_ips.append(ipaddress.ip_network(ip_subnet))
snitch["Config"]["Log ignore"].remove(ip_subnet)
except Exception as e:
pass
snitch["Config"]["Log ignore IP"] = ignored_ips
# main loop
transaction = []
new_processes = []
last_write = 0
while True:
if not parent_process.is_alive():
return 0
try:
# prep to receive new connections
if secondary_pipe.poll():
q_error.put("sync error between secondary and primary on ready (pipe not empty)")
else:
q_primary_in.put(pickle.dumps({"type": "ready"}))
secondary_pipe.poll(timeout=300)
if not secondary_pipe.poll():
q_error.put("sync error between secondary and primary on ready (secondary timed out waiting for first message)")
# receive first message, should be transfer size
transfer_size = 0
if secondary_pipe.poll():
first_pickle = secondary_pipe.recv_bytes()
if type(pickle.loads(first_pickle)) == int:
transfer_size = pickle.loads(first_pickle)
elif pickle.loads(first_pickle) == "done":
q_error.put("sync error between secondary and primary on ready (received done)")
else:
q_error.put("sync error between secondary and primary on ready (did not receive transfer size)")
new_processes.append(first_pickle)
# receive new connections until "done"
timeout_counter = 0
while True:
while secondary_pipe.poll(timeout=1):
new_processes.append(secondary_pipe.recv_bytes())
transfer_size -= 1
timeout_counter += 1
if pickle.loads(new_processes[-1]) == "done":
_ = new_processes.pop()
transfer_size += 1
break
elif timeout_counter > 30:
q_error.put("sync error between secondary and primary on receive (did not receive done)")
if transfer_size > 0:
q_error.put("sync error between secondary and primary on receive (did not receive all messages)")
elif transfer_size < 0:
q_error.put("sync error between secondary and primary on receive (received extra messages)")
# check for other pending data (vt, fanotify)
get_vt_results(snitch, p_virustotal.q_out, q_primary_in, False)
get_fanotify_events(fan_fd, fan_mod_cnt, q_error)
# process connection data
if time.time() - last_write > snitch["Config"]["DB write limit (seconds)"] and (transaction or new_processes):
current_write = time.time()
transaction += secondary_subprocess_helper(snitch, fan_mod_cnt, new_processes, p_rfuse, p_virustotal.q_in, q_primary_in, q_error)
new_processes = []
transaction_success = False
try:
if snitch["Config"]["DB sql log"]:
con = sqlite3.connect(file_path)
with con:
con.executemany(sqlite_query, transaction)
con.close()
transaction_success = True
except Exception as e:
q_error.put("SQLite execute %s%s on line %s, lost %s entries" % (type(e).__name__, str(e.args), sys.exc_info()[2].tb_lineno, len(transaction)))
try:
if sql_kwargs:
con = sql.connect(**sql_kwargs)
with con.cursor() as cur:
cur.executemany(sql_query, transaction)
con.commit()
con.close()
transaction_success = True
except Exception as e:
q_error.put("SQL server execute %s%s on line %s, lost %s entries" % (type(e).__name__, str(e.args), sys.exc_info()[2].tb_lineno, len(transaction)))
try:
if snitch["Config"]["DB text log"]:
with open(text_path, "a", encoding="utf-8", errors="surrogateescape") as text_file:
for entry in transaction:
clean_entry = [str(value).replace(",", "").replace("\n", "").replace("\0", "") for value in entry]
text_file.write(",".join(clean_entry) + "\n")
transaction_success = True
except Exception as e:
q_error.put("text log %s%s on line %s, lost %s entries" % (type(e).__name__, str(e.args), sys.exc_info()[2].tb_lineno, len(transaction)))
if transaction_success or log_destinations == 0:
transaction = []
else:
q_error.put("secondary subprocess all log desinations failed, will retry %s entries with next write" % (len(transaction)))
last_write = current_write
except Exception as e:
q_error.put("secondary subprocess %s%s on line %s" % (type(e).__name__, str(e.args), sys.exc_info()[2].tb_lineno))
def rfuse_subprocess(config: dict, q_error, q_in, q_out):
"""runs as user to read executables for FUSE/AppImage (since real, effective, and saved UID must match)"""
parent_process = multiprocessing.parent_process()
try:
os.setgid(int(os.getenv("SUDO_UID")))
os.setuid(int(os.getenv("SUDO_UID")))
except Exception:
pass
while True:
if not parent_process.is_alive():
return 0
try:
path, pid, st_dev, st_ino = pickle.loads(q_in.get(block=True, timeout=15))
sha256 = get_sha256_fd.__wrapped__(path, st_dev, st_ino, 0)
if sha256.startswith("!"):
sha256 = get_sha256_pid.__wrapped__(pid, st_dev, st_ino)
if sha256.startswith("!"):
sha256 = "!!! FUSE Read Error"
q_out.put(sha256)
except queue.Empty:
pass
except Exception as e:
q_error.put("rfuse subprocess %s%s on line %s" % (type(e).__name__, str(e.args), sys.exc_info()[2].tb_lineno))