feat(v2): complete v2 reimplementation

tests/security/test_restore_paths.py

@@ -0,0 +1,74 @@
+from __future__ import annotations
+
+import importlib
+import stat
+from pathlib import Path
+
+import pytest
+from backup_tool.config import Settings
+
+snapshot = importlib.import_module("backup_tool.snapshot")
+
+
+def settings_for(tmp_path: Path) -> Settings:
+    key = tmp_path / "master.key"
+    key.write_bytes(b"m6-restore-path-test-master-key-material")
+    key.chmod(0o600)
+    repositories = tmp_path / "repositories"
+    sources = tmp_path / "sources"
+    restores = tmp_path / "restores"
+    for directory in (repositories, sources, restores):
+        directory.mkdir()
+    return Settings(
+        data_dir=tmp_path,
+        database_url=f"sqlite+aiosqlite:///{tmp_path / 'metadata.db'}",
+        repository_roots=(repositories,),
+        local_source_roots=(sources,),
+        restore_roots=(restores,),
+        master_key_file=key,
+        min_free_bytes=1,
+    )
+
+
+@pytest.mark.parametrize("name", ["existing", "outside", "root"])
+def test_restore_destination_rejects_existing_or_outside_paths(tmp_path: Path, name: str) -> None:
+    settings = settings_for(tmp_path)
+    root = settings.restore_roots[0]
+    outside = tmp_path / "outside"
+    outside.mkdir()
+    existing = root / "existing"
+    existing.mkdir()
+    destinations = {
+        "existing": existing,
+        "outside": outside / "restore",
+        "root": root,
+    }
+
+    with pytest.raises(snapshot.SnapshotError):
+        snapshot.validate_restore_destination(settings, str(destinations[name]))
+
+
+def test_restore_strips_special_permission_bits(tmp_path: Path) -> None:
+    target = tmp_path / "restored"
+    target.write_bytes(b"content")
+
+    snapshot._apply_metadata(
+        target,
+        {"metadata_support": ["mode"], "mode": 0o7777},
+    )
+
+    mode = stat.S_IMODE(target.stat().st_mode)
+    assert mode == 0o777
+    assert mode & (stat.S_ISUID | stat.S_ISGID | stat.S_ISVTX) == 0
+
+
+def test_restore_destination_rejects_a_symlinked_parent(tmp_path: Path) -> None:
+    settings = settings_for(tmp_path)
+    outside = tmp_path / "outside"
+    outside.mkdir()
+    (settings.restore_roots[0] / "linked").symlink_to(outside, target_is_directory=True)
+
+    with pytest.raises(snapshot.SnapshotError):
+        snapshot.validate_restore_destination(
+            settings, str(settings.restore_roots[0] / "linked" / "restore")
+        )