fix(app): directory traversal when deleting images

invokeai/app/services/image_files/image_files_disk.py

@@ -110,15 +110,26 @@ def delete(self, image_name: str) -> None:
  except Exception as e:
  raise ImageFileDeleteException from e
 
- # TODO: make this a bit more flexible for e.g. cloud storage
  def get_path(self, image_name: str, thumbnail: bool = False) -> Path:
- path = self.__output_folder / image_name
+ base_folder = self.__thumbnails_folder if thumbnail else self.__output_folder
+ filename = get_thumbnail_name(image_name) if thumbnail else image_name
 
- if thumbnail:
- thumbnail_name = get_thumbnail_name(image_name)
- path = self.__thumbnails_folder / thumbnail_name
+ # Strip any path information from the filename
+ basename = Path(filename).name
+
+ if basename != filename:
+ raise ValueError("Invalid image name, potential directory traversal detected")
+
+ image_path = base_folder / basename
+
+ # Ensure the image path is within the base folder to prevent directory traversal
+ resolved_base = base_folder.resolve()
+ resolved_image_path = image_path.resolve()
+
+ if not resolved_image_path.is_relative_to(resolved_base):
+ raise ValueError("Image path outside outputs folder, potential directory traversal detected")
 
- return path
+ return resolved_image_path
 
  def validate_path(self, path: Union[str, Path]) -> bool:
  """Validates the path given for an image or thumbnail."""

tests/app/services/image_files/test_image_files_disk.py

@@ -0,0 +1,51 @@
+import platform
+from pathlib import Path
+
+import pytest
+
+from invokeai.app.services.image_files.image_files_disk import DiskImageFileStorage
+
+
+@pytest.fixture
+def image_names() -> list[str]:
+ # Determine the platform and return a path that matches its format
+ if platform.system() == "Windows":
+ return [
+ # Relative paths
+ "folder\\evil.txt",
+ "folder\\..\\evil.txt",
+ # Absolute paths
+ "\\folder\\evil.txt",
+ "C:\\folder\\..\\evil.txt",
+ ]
+ else:
+ return [
+ # Relative paths
+ "folder/evil.txt",
+ "folder/../evil.txt",
+ # Absolute paths
+ "/folder/evil.txt",
+ "/folder/../evil.txt",
+ ]
+
+
+def test_directory_traversal_protection(tmp_path: Path, image_names: list[str]):
+ """Test that the image file storage prevents directory traversal attacks.
+
+ There are two safeguards in the `DiskImageFileStorage.get_path` method:
+ 1. Check if the image name contains any directory traversal characters
+ 2. Check if the resulting path is relative to the base folder
+
+ This test checks the first safeguard. I'd like to check the second but I cannot figure out a test case that would
+ pass the first check but fail the second check.
+ """
+ image_files_disk = DiskImageFileStorage(tmp_path)
+ for name in image_names:
+ with pytest.raises(ValueError, match="Invalid image name, potential directory traversal detected"):
+ image_files_disk.get_path(name)
+
+
+def test_image_paths_relative_to_storage_dir(tmp_path: Path):
+ image_files_disk = DiskImageFileStorage(tmp_path)
+ path = image_files_disk.get_path("foo.png")
+ assert path.is_relative_to(tmp_path)