fix(sync): S-02 — platform-independent path construction avoids path traversal

tests/sync_test.rs

@@ -397,11 +397,7 @@ fn test_s01_pull_delete_preserves_local_excluded_and_leak_files() {
         b"Album Art or Explorer Cache",
     )
     .unwrap();
-    fs::write(
-        restore_dir.join("local_notes.pdf"),
-        b"Private Local Notes",
-    )
-    .unwrap();
+    fs::write(restore_dir.join("local_notes.pdf"), b"Private Local Notes").unwrap();
 
     let (db, dek) = create_test_container(&container_path);
 
@@ -462,3 +458,107 @@ fn test_s01_pull_delete_preserves_local_excluded_and_leak_files() {
     let _ = fs::remove_dir_all(&temp_root);
 }
 
+#[test]
+fn test_s02_platform_independent_path_construction_and_traversal_rejection() {
+    let temp_root =
+        std::env::temp_dir().join(format!("sanctum_s02_test_{}", rand::random::<u64>()));
+    let container_path = temp_root.join("test.sanctum");
+    let source_dir = temp_root.join("source");
+    let target_dir = temp_root.join("restored");
+
+    fs::create_dir_all(&source_dir).unwrap();
+    let deep_dir = source_dir.join("level1").join("level2").join("level3");
+    fs::create_dir_all(&deep_dir).unwrap();
+    fs::write(deep_dir.join("deep_doc.txt"), b"Deeply nested content").unwrap();
+
+    let (db, dek) = create_test_container(&container_path);
+
+    // 1. Push: Übertrage mehrstufige Verzeichnisstruktur in den Tresor
+    let mut push_opts = SyncOptions::default();
+    push_opts.direction = SyncDirection::Push;
+    push_opts.quiet = true;
+
+    run_sync(
+        &db,
+        0,
+        &dek,
+        FORMAT_VERSION,
+        source_dir.to_str().unwrap(),
+        "/MultiLevel",
+        &push_opts,
+    )
+    .expect("Sync push multi-level");
+
+    // 2. Pull: Prüfe, dass mehrstufige Pfade plattformunabhängig rekonstruiert werden
+    let mut pull_opts = SyncOptions::default();
+    pull_opts.direction = SyncDirection::Pull;
+    pull_opts.quiet = true;
+
+    run_sync(
+        &db,
+        0,
+        &dek,
+        FORMAT_VERSION,
+        "/MultiLevel",
+        target_dir.to_str().unwrap(),
+        &pull_opts,
+    )
+    .expect("Sync pull multi-level");
+
+    let restored_file = target_dir
+        .join("level1")
+        .join("level2")
+        .join("level3")
+        .join("deep_doc.txt");
+    assert!(
+        restored_file.exists(),
+        "Mehrstufige Datei muss korrekt auf dem Host angelegt worden sein"
+    );
+    assert_eq!(fs::read(restored_file).unwrap(), b"Deeply nested content");
+
+    // 3. Traversal-Abwehr: Bösartiger Knoten mit relativem Ausbruchsversuch
+    // Simuliere manipulierten Knoten im Tresor
+    {
+        let conn = rusqlite::Connection::open(&container_path).unwrap();
+        // Erstelle Knoten mit manipuliertem Namen '../evil.txt'
+        conn.execute(
+            "INSERT INTO nodes (id, parent_id, name, is_dir, size, created_at, modified_at, is_carrier)
+             VALUES (9999, 1, '../evil.txt', 0, 10, 100, 100, 0)",
+            [],
+        )
+        .unwrap();
+    }
+
+    let malicious_target = temp_root.join("malicious_target");
+    fs::create_dir_all(&malicious_target).unwrap();
+
+    let pull_res = run_sync(
+        &db,
+        0,
+        &dek,
+        FORMAT_VERSION,
+        "/",
+        malicious_target.to_str().unwrap(),
+        &pull_opts,
+    );
+
+    assert!(
+        pull_res.is_err(),
+        "Sync Pull muss bei manipuliertem Traversal-Pfad abbrechen"
+    );
+    let err_msg = pull_res.unwrap_err().to_string();
+    assert!(
+        err_msg.contains("Path traversal")
+            || err_msg.contains("Ungültiger Dateiname")
+            || err_msg.contains("unzulässige Trennzeichen"),
+        "Fehlermeldung muss Traversal-Erkennung ausweisen: {}",
+        err_msg
+    );
+    assert!(
+        !temp_root.join("evil.txt").exists(),
+        "Es darf niemals eine Datei außerhalb des Zielverzeichnisses erzeugt werden"
+    );
+
+    // Aufräumen
+    let _ = fs::remove_dir_all(&temp_root);
+}