Files
LEDMatrix/test/web_interface/test_systemctl_sudoers_alignment.py
Ron Pierce 122e6d6863 fix(web): use fully-qualified .service unit names for privileged systemctl (#360)
The web interface runs headless, so every privileged systemctl call must be
covered by a NOPASSWD rule in /etc/sudoers.d/ledmatrix_web. The sudo command
matches the command line exactly, but the code called 'systemctl start
ledmatrix' while configure_web_sudo.sh grants 'systemctl start
ledmatrix.service'. The rule never matched, so start/stop/enable/disable/
restart fell back to a password prompt and failed with 'a terminal is
required to read the password'.

Align all privileged systemctl calls on the fully-qualified unit names the
sudoers grants use. Add a regression test that cross-checks api_v3.py calls
against the grants in configure_web_sudo.sh.

Co-authored-by: Claude Opus 4.8 <noreply@anthropic.com>
2026-06-04 15:17:00 -04:00

77 lines
3.1 KiB
Python

"""Guards that every privileged systemctl call the web interface makes is
covered by a passwordless-sudo grant in configure_web_sudo.sh.
The web interface runs headless (no TTY), so any `sudo` call that is not
matched by a NOPASSWD rule in /etc/sudoers.d/ledmatrix_web falls back to a
password prompt and fails with:
sudo: a terminal is required to read the password
sudo matches the command line by exact string, so `systemctl start ledmatrix`
and `systemctl start ledmatrix.service` are NOT interchangeable. This test
parses both the production blueprint and the sudoers-generator script and
asserts the (verb, unit) pairs line up, catching the suffix-mismatch class of
bug before it ships.
"""
import ast
import re
from pathlib import Path
PROJECT_ROOT = Path(__file__).resolve().parents[2]
API_V3 = PROJECT_ROOT / "web_interface" / "blueprints" / "api_v3.py"
SUDOERS_SCRIPT = PROJECT_ROOT / "scripts" / "install" / "configure_web_sudo.sh"
def _sudo_systemctl_calls(source: str) -> set[tuple[str, str]]:
"""Return (verb, unit) for every list literal beginning with
['sudo', 'systemctl', ...] passed to a subprocess call in the source."""
calls: set[tuple[str, str]] = set()
for node in ast.walk(ast.parse(source)):
if not isinstance(node, ast.List):
continue
elts = node.elts
if len(elts) < 4:
continue
if not all(isinstance(e, ast.Constant) and isinstance(e.value, str) for e in elts[:4]):
continue
if elts[0].value == "sudo" and elts[1].value == "systemctl":
calls.add((elts[2].value, elts[3].value))
return calls
def _granted_systemctl_rules(script: str) -> set[tuple[str, str]]:
"""Return (verb, unit) for each `$SYSTEMCTL_PATH <verb> <unit>` NOPASSWD
grant emitted by the sudoers-generator script."""
rules: set[tuple[str, str]] = set()
for match in re.finditer(r"\$SYSTEMCTL_PATH\s+(\S+)\s+(\S+)", script):
verb, unit = match.group(1), match.group(2).rstrip('"')
rules.add((verb, unit))
return rules
def test_every_sudo_systemctl_call_is_granted() -> None:
calls = _sudo_systemctl_calls(API_V3.read_text())
rules = _granted_systemctl_rules(SUDOERS_SCRIPT.read_text())
assert calls, "expected to find sudo systemctl calls in api_v3.py"
uncovered = {c for c in calls if c not in rules}
assert not uncovered, (
"These sudo systemctl calls have no matching NOPASSWD grant in "
"configure_web_sudo.sh; they will fail headless with "
"'sudo: a terminal is required to read the password': "
+ ", ".join(f"systemctl {v} {u}" for v, u in sorted(uncovered))
)
def test_units_are_fully_qualified() -> None:
"""Privileged systemctl calls must name the unit as <name>.service so they
match the sudoers grants, which use the fully-qualified unit name."""
calls = _sudo_systemctl_calls(API_V3.read_text())
unqualified = {(v, u) for v, u in calls if not u.endswith(".service")}
assert not unqualified, (
"sudo systemctl calls must use fully-qualified .service unit names: "
+ ", ".join(f"systemctl {v} {u}" for v, u in sorted(unqualified))
)