File size: 1,567 Bytes
06cfa3d | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 | """Prove that a listening TCP socket belongs to the attested candidate process."""
from __future__ import annotations
import os
from pathlib import Path
import sys
def owns_tcp_listener(pid: int, port: int, parent_pid: int) -> bool:
process = Path('/proc') / str(pid)
try:
state = (process / 'stat').read_text().rsplit(')', 1)[1].split()
if state[0] == 'Z' or int(state[1]) != parent_pid:
return False
sockets = set()
for entry in (process / 'fd').iterdir():
try:
target = os.readlink(entry)
except FileNotFoundError:
continue
if target.startswith('socket:[') and target.endswith(']'):
sockets.add(target[8:-1])
if not sockets:
return False
for table in ('tcp', 'tcp6'):
try:
rows = (process / 'net' / table).read_text().splitlines()[1:]
except FileNotFoundError:
continue
for row in rows:
fields = row.split()
if (len(fields) > 9 and fields[3] == '0A'
and int(fields[1].rsplit(':', 1)[1], 16) == port
and fields[9] in sockets):
return True
return False
except FileNotFoundError:
return False
if __name__ == '__main__':
try:
matched = owns_tcp_listener(*(int(value) for value in sys.argv[1:]))
except (OSError, ValueError):
raise SystemExit(2)
raise SystemExit(0 if matched else 1)
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