Files
backup-tool/tests/security/test_recovery_bundle.py
T

161 lines
5.3 KiB
Python

from __future__ import annotations
import asyncio
import os
from pathlib import Path
import pytest
from alembic import command
from backup_tool.cli import build_alembic_config, build_parser
from backup_tool.cli import main as cli_main
from backup_tool.db.engine import create_engine
from backup_tool.db.models import Repository, RepositoryDataKeyEpoch
from backup_tool.repository import initialize
from backup_tool.security.recovery_bundle import (
RecoveryBundleError,
RecoveryBundlePathError,
decrypt_bundle,
encrypt_bundle,
write_bundle_exclusive,
)
from sqlalchemy.ext.asyncio import async_sessionmaker
from tests.conftest import make_settings
PASSPHRASE = b"correct horse battery staple"
def _passphrase_fd(value: bytes) -> int:
read_fd, write_fd = os.pipe()
os.write(write_fd, value + b"\n")
os.close(write_fd)
return read_fd
def test_recovery_bundle_rejects_wrong_passphrase_tampering_and_invalid_kdf() -> None:
bundle = encrypt_bundle({"catalog": {"version": 1}, "keys": []}, PASSPHRASE)
tampered = bundle[:-1] + bytes([bundle[-1] ^ 1])
unsupported_kdf = bundle[:6] + b"\x02" + bundle[7:]
for encoded, passphrase in (
(bundle, b"wrong passphrase"),
(tampered, PASSPHRASE),
(unsupported_kdf, PASSPHRASE),
):
with pytest.raises(RecoveryBundleError, match="^recovery bundle is invalid$"):
decrypt_bundle(encoded, passphrase)
def test_recovery_bundle_output_is_exclusive_and_does_not_follow_symlinks(
tmp_path: Path,
) -> None:
bundle = encrypt_bundle({"catalog": {"version": 1}, "keys": []}, PASSPHRASE)
existing = tmp_path / "existing.btrec"
existing.write_bytes(b"keep")
with pytest.raises(RecoveryBundlePathError, match="^recovery bundle output is unsafe$"):
write_bundle_exclusive(existing, bundle)
assert existing.read_bytes() == b"keep"
target = tmp_path / "target.btrec"
target.write_bytes(b"keep")
symlink = tmp_path / "link.btrec"
symlink.symlink_to(target)
with pytest.raises(RecoveryBundlePathError, match="^recovery bundle output is unsafe$"):
write_bundle_exclusive(symlink, bundle)
assert target.read_bytes() == b"keep"
def test_cli_recovery_export_validate_uses_fd_and_hides_plaintext_keys(
tmp_path: Path, capsys: pytest.CaptureFixture[str]
) -> None:
settings = make_settings(tmp_path)
command.upgrade(build_alembic_config(settings), "head")
initialized = initialize(settings, "encrypted", "none", "aes-256-gcm")
assert initialized.data_key_id is not None
assert initialized.data_key_path is not None
async def create_repository() -> None:
engine = create_engine(settings)
sessions = async_sessionmaker(engine, expire_on_commit=False)
try:
async with sessions() as db:
repository = Repository(
name="encrypted",
root=str(initialized.root),
format_version=initialized.format_version,
compression=initialized.compression,
encryption=initialized.encryption,
signing_key_id=initialized.signing_key_id,
signing_public_key=initialized.signing_public_key,
active_data_key_id=initialized.data_key_id,
)
db.add(repository)
await db.flush()
db.add(
RepositoryDataKeyEpoch(
repository_id=repository.id,
key_id=initialized.data_key_id,
state="active",
)
)
await db.commit()
finally:
await engine.dispose()
asyncio.run(create_repository())
output = tmp_path / "recovery.btrec"
export_fd = _passphrase_fd(PASSPHRASE)
try:
assert (
cli_main(
[
"admin",
"recovery",
"export",
"--output",
str(output),
"--passphrase-fd",
str(export_fd),
],
settings=settings,
)
== 0
)
finally:
os.close(export_fd)
export_output = capsys.readouterr().out
bundle = output.read_bytes()
assert bundle.startswith(b"BTREC\x01")
assert initialized.data_key_path.read_bytes() not in bundle
signing_key_path = (
settings.data_dir / "repository-keys" / f"{initialized.repository_id}.ed25519"
)
assert signing_key_path.read_bytes() not in bundle
assert "key" not in export_output.lower()
validate_fd = _passphrase_fd(PASSPHRASE)
try:
assert (
cli_main(
[
"admin",
"recovery",
"validate",
"--input",
str(output),
"--passphrase-fd",
str(validate_fd),
],
settings=settings,
)
== 0
)
finally:
os.close(validate_fd)
assert capsys.readouterr().out == '{"repositories": 1, "status": "valid"}\n'
parser = build_parser()
with pytest.raises(SystemExit):
parser.parse_args(["admin", "recovery", "export", "--passphrase", "not-allowed"])