Files
LEDMatrix/test/test_backup_manager.py
T
ChuckBuildsandClaude Opus 5 cbe6240665 fix(backup): restore must not depend on owning the file it replaces
Follow-up from testing the previous commit on real hardware, where the
secrets fix turned out to be both too narrow and slightly wrong.

Too narrow: config.json, wifi_config.json and ytm_auth.json are installed
root-owned and group-readable exactly like the secrets file, so all four
were unrestorable by the web service, not just one. `shutil.copy2` opens
the destination for writing, which needs permission on the *existing
file*; the web user could create files in that directory all day and
still not replace them.

Slightly wrong: the previous commit loosened the secrets file to
group-writable. That was treating the symptom. The real error was
deciding ownership from `ledmatrix.service` -- the display service, which
runs as root and only ever *reads* secrets -- when the account that
*writes* them is the web interface, which deliberately does not run as
root. Ownership now follows the web service's user and the mode stays
640.

`_copy_file` writes a temporary file alongside the target and renames
over it. That needs only directory permission, so a restore no longer
cares who owns the destination, and it is atomic: a crash mid-restore can
no longer leave a half-written config. The destination's mode is carried
across so restoring secrets does not widen them to the umask, and its
owner is carried across too when the OS allows it -- only root can hand a
file to another user, so a restore run by the web service keeps its own
ownership rather than pretending to preserve root's.

Verified on a device with all four config files set root-owned 640 and
unwritable by the web user: before, every one failed with EACCES; after,
the restore reports success with no errors and all four sections
restored, mode still 640, root still able to read them and the web
service still able to write them.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Udr6MfaFLUPhX5Fgo67Jf5
2026-08-06 13:43:11 -04:00

333 lines
13 KiB
Python

"""Tests for src.backup_manager."""
from __future__ import annotations
import json
import stat
import zipfile
from pathlib import Path
import pytest
from src import backup_manager
from src.backup_manager import (
BUNDLED_FONTS,
SCHEMA_VERSION,
RestoreOptions,
create_backup,
list_installed_plugins,
preview_backup_contents,
restore_backup,
validate_backup,
)
# ---------------------------------------------------------------------------
# Fixtures
# ---------------------------------------------------------------------------
def _make_project(root: Path) -> Path:
"""Build a minimal fake project tree under ``root``."""
(root / "config").mkdir(parents=True)
(root / "config" / "config.json").write_text(
json.dumps({"web_ui": {"port": 8080}, "my-plugin": {"enabled": True, "favorites": ["A", "B"]}}),
encoding="utf-8",
)
(root / "config" / "config_secrets.json").write_text(
json.dumps({"ledmatrix-weather": {"api_key": "SECRET"}}),
encoding="utf-8",
)
(root / "config" / "wifi_config.json").write_text(
json.dumps({"ap_mode": {"ssid": "LEDMatrix"}}),
encoding="utf-8",
)
# Device-local auth that lives in config/ like the three above. It was
# omitted from backups, so a restore silently signed the user out of
# YouTube Music and they had to re-authenticate by hand.
(root / "config" / "ytm_auth.json").write_text(
json.dumps({"token": "YTM-TOKEN"}),
encoding="utf-8",
)
fonts = root / "assets" / "fonts"
fonts.mkdir(parents=True)
# One bundled font (should be excluded) and one user-uploaded font.
(fonts / "5x7.bdf").write_text("BUNDLED", encoding="utf-8")
(fonts / "my-custom-font.ttf").write_bytes(b"\x00\x01USER")
uploads = root / "assets" / "plugins" / "static-image" / "uploads"
uploads.mkdir(parents=True)
(uploads / "image_1.png").write_bytes(b"\x89PNG\r\n\x1a\nfake")
(uploads / ".metadata.json").write_text(json.dumps({"a": 1}), encoding="utf-8")
# plugin-repos for installed-plugin enumeration.
plugin_dir = root / "plugin-repos" / "my-plugin"
plugin_dir.mkdir(parents=True)
(plugin_dir / "manifest.json").write_text(
json.dumps({"id": "my-plugin", "version": "1.2.3"}),
encoding="utf-8",
)
# plugin_state.json
(root / "data").mkdir()
(root / "data" / "plugin_state.json").write_text(
json.dumps(
{
"version": 1,
"states": {
"my-plugin": {"version": "1.2.3", "enabled": True},
"other-plugin": {"version": "0.1.0", "enabled": False},
},
}
),
encoding="utf-8",
)
return root
@pytest.fixture
def project(tmp_path: Path) -> Path:
return _make_project(tmp_path / "src_project")
@pytest.fixture
def empty_project(tmp_path: Path) -> Path:
root = tmp_path / "dst_project"
root.mkdir()
# Pre-seed only the bundled font to simulate a fresh install.
(root / "assets" / "fonts").mkdir(parents=True)
(root / "assets" / "fonts" / "5x7.bdf").write_text("BUNDLED", encoding="utf-8")
return root
# ---------------------------------------------------------------------------
# BUNDLED_FONTS sanity
# ---------------------------------------------------------------------------
def test_bundled_fonts_matches_repo() -> None:
"""Every entry in BUNDLED_FONTS must exist on disk in assets/fonts/.
The reverse direction is intentionally not checked: real installations
have user-uploaded fonts in the same directory, and they should be
treated as user data (not bundled).
"""
repo_fonts = Path(__file__).resolve().parent.parent / "assets" / "fonts"
if not repo_fonts.exists():
pytest.skip("assets/fonts not present in test env")
on_disk = {p.name for p in repo_fonts.iterdir() if p.is_file()}
missing = set(BUNDLED_FONTS) - on_disk
assert not missing, f"BUNDLED_FONTS references files not in assets/fonts/: {missing}"
# ---------------------------------------------------------------------------
# Preview / enumeration
# ---------------------------------------------------------------------------
def test_list_installed_plugins(project: Path) -> None:
plugins = list_installed_plugins(project)
ids = [p["plugin_id"] for p in plugins]
assert "my-plugin" in ids
assert "other-plugin" in ids
my = next(p for p in plugins if p["plugin_id"] == "my-plugin")
assert my["version"] == "1.2.3"
def test_preview_backup_contents(project: Path) -> None:
preview = preview_backup_contents(project)
assert preview["has_config"] is True
assert preview["has_secrets"] is True
assert preview["has_wifi"] is True
assert preview["user_fonts"] == ["my-custom-font.ttf"]
assert preview["plugin_uploads"] >= 2
assert any(p["plugin_id"] == "my-plugin" for p in preview["plugins"])
# ---------------------------------------------------------------------------
# Export
# ---------------------------------------------------------------------------
def test_create_backup_contents(project: Path, tmp_path: Path) -> None:
out_dir = tmp_path / "exports"
zip_path = create_backup(project, output_dir=out_dir)
assert zip_path.exists()
assert zip_path.parent == out_dir
with zipfile.ZipFile(zip_path) as zf:
names = set(zf.namelist())
assert "manifest.json" in names
assert "config/config.json" in names
assert "config/config_secrets.json" in names
assert "config/wifi_config.json" in names
assert "assets/fonts/my-custom-font.ttf" in names
# Bundled font must NOT be included.
assert "assets/fonts/5x7.bdf" not in names
assert "assets/plugins/static-image/uploads/image_1.png" in names
assert "plugins.json" in names
def test_create_backup_manifest(project: Path, tmp_path: Path) -> None:
zip_path = create_backup(project, output_dir=tmp_path / "exports")
with zipfile.ZipFile(zip_path) as zf:
manifest = json.loads(zf.read("manifest.json"))
assert manifest["schema_version"] == backup_manager.SCHEMA_VERSION
assert "created_at" in manifest
assert set(manifest["contents"]) >= {"config", "secrets", "wifi", "fonts", "plugin_uploads", "plugins"}
# ---------------------------------------------------------------------------
# Validate
# ---------------------------------------------------------------------------
def test_validate_backup_ok(project: Path, tmp_path: Path) -> None:
zip_path = create_backup(project, output_dir=tmp_path / "exports")
ok, err, manifest = validate_backup(zip_path)
assert ok, err
assert err == ""
assert "config" in manifest["detected_contents"]
assert "secrets" in manifest["detected_contents"]
assert any(p["plugin_id"] == "my-plugin" for p in manifest["plugins"])
def test_validate_backup_missing_manifest(tmp_path: Path) -> None:
zip_path = tmp_path / "bad.zip"
with zipfile.ZipFile(zip_path, "w") as zf:
zf.writestr("config/config.json", "{}")
ok, err, _ = validate_backup(zip_path)
assert not ok
assert "manifest" in err.lower()
def test_validate_backup_bad_schema_version(tmp_path: Path) -> None:
zip_path = tmp_path / "bad.zip"
with zipfile.ZipFile(zip_path, "w") as zf:
zf.writestr("manifest.json", json.dumps({"schema_version": 999}))
ok, err, _ = validate_backup(zip_path)
assert not ok
assert "schema" in err.lower()
def test_validate_backup_rejects_zip_traversal(tmp_path: Path) -> None:
zip_path = tmp_path / "malicious.zip"
with zipfile.ZipFile(zip_path, "w") as zf:
zf.writestr("manifest.json", json.dumps({"schema_version": SCHEMA_VERSION, "contents": []}))
zf.writestr("../../etc/passwd", "x")
ok, err, _ = validate_backup(zip_path)
assert not ok
assert "unsafe" in err.lower()
def test_validate_backup_not_a_zip(tmp_path: Path) -> None:
p = tmp_path / "nope.zip"
p.write_text("hello", encoding="utf-8")
ok, _err, _ = validate_backup(p)
assert not ok
# ---------------------------------------------------------------------------
# Restore
# ---------------------------------------------------------------------------
def test_restore_roundtrip(project: Path, empty_project: Path, tmp_path: Path) -> None:
zip_path = create_backup(project, output_dir=tmp_path / "exports")
result = restore_backup(zip_path, empty_project, RestoreOptions())
assert result.success, result.errors
assert "config" in result.restored
assert "secrets" in result.restored
assert "wifi" in result.restored
# Files exist with correct contents.
restored_config = json.loads((empty_project / "config" / "config.json").read_text())
assert restored_config["my-plugin"]["favorites"] == ["A", "B"]
restored_secrets = json.loads((empty_project / "config" / "config_secrets.json").read_text())
assert restored_secrets["ledmatrix-weather"]["api_key"] == "SECRET"
assert "ytm_auth" in result.restored
restored_ytm = json.loads((empty_project / "config" / "ytm_auth.json").read_text())
assert restored_ytm["token"] == "YTM-TOKEN"
# User font restored, bundled font untouched.
assert (empty_project / "assets" / "fonts" / "my-custom-font.ttf").read_bytes() == b"\x00\x01USER"
assert (empty_project / "assets" / "fonts" / "5x7.bdf").read_text() == "BUNDLED"
# Plugin uploads restored.
assert (empty_project / "assets" / "plugins" / "static-image" / "uploads" / "image_1.png").exists()
# Plugins to install surfaced for the caller.
plugin_ids = {p["plugin_id"] for p in result.plugins_to_install}
assert "my-plugin" in plugin_ids
def test_restore_honors_options(project: Path, empty_project: Path, tmp_path: Path) -> None:
zip_path = create_backup(project, output_dir=tmp_path / "exports")
opts = RestoreOptions(
restore_config=True,
restore_secrets=False,
restore_wifi=False,
restore_fonts=False,
restore_plugin_uploads=False,
reinstall_plugins=False,
)
result = restore_backup(zip_path, empty_project, opts)
assert result.success, result.errors
assert (empty_project / "config" / "config.json").exists()
assert not (empty_project / "config" / "config_secrets.json").exists()
assert not (empty_project / "config" / "wifi_config.json").exists()
assert not (empty_project / "assets" / "fonts" / "my-custom-font.ttf").exists()
assert result.plugins_to_install == []
assert "secrets" in result.skipped
assert "wifi" in result.skipped
def test_restore_rejects_malicious_zip(empty_project: Path, tmp_path: Path) -> None:
zip_path = tmp_path / "bad.zip"
with zipfile.ZipFile(zip_path, "w") as zf:
zf.writestr("manifest.json", json.dumps({"schema_version": SCHEMA_VERSION, "contents": []}))
zf.writestr("../escape.txt", "x")
result = restore_backup(zip_path, empty_project, RestoreOptions())
# validate_backup catches it before extraction.
assert not result.success
assert any("unsafe" in e.lower() for e in result.errors)
def test_restore_over_a_file_the_user_cannot_write(
project: Path, empty_project: Path, tmp_path: Path
) -> None:
"""Restore must not need write permission on the destination *file*.
Reproduces what a fresh install leaves behind: config files owned by root
and only group-readable, while the web interface that performs the restore
runs as a non-root user. shutil.copy2 opens the destination for writing and
failed with EACCES; writing alongside and renaming needs only directory
permission, which that account has.
Simulated here by making the destination read-only — the owner cannot
open it for writing either, but can still replace it within its directory.
"""
zip_path = create_backup(project, output_dir=tmp_path / "exports")
# Pre-existing, read-only destinations.
(empty_project / "config").mkdir(parents=True, exist_ok=True)
for name in ("config.json", "config_secrets.json", "wifi_config.json", "ytm_auth.json"):
target = empty_project / "config" / name
target.write_text("{}", encoding="utf-8")
target.chmod(0o444)
result = restore_backup(zip_path, empty_project, RestoreOptions())
assert result.success, result.errors
for section in ("config", "secrets", "wifi", "ytm_auth"):
assert section in result.restored, f"{section} not restored: {result.errors}"
restored = json.loads((empty_project / "config" / "config.json").read_text())
assert restored["my-plugin"]["favorites"] == ["A", "B"]
# The destination's mode is preserved rather than widened to the umask.
assert stat.S_IMODE((empty_project / "config" / "config_secrets.json").stat().st_mode) == 0o444