* fix: prevent pickle deserialization of untrusted HITL input
Add strip_pickle_markers() to sanitize HTTP input before it reaches
pickle.loads() via the checkpoint decoding path. Applied as a 3-layer
defence-in-depth:
1. _app.py: sanitize req.get_json() at the HTTP boundary
2. _workflow.py: sanitize in _deserialize_hitl_response() before decode
3. _serialization.py: sanitize in reconstruct_to_type() as final guard
Any dict containing __pickled__ or __type__ markers from untrusted
sources is replaced with None, blocking arbitrary code execution via
crafted payloads to POST /workflow/respond/{instanceId}/{requestId}.
Includes 12 new unit tests covering the sanitizer and end-to-end
attack prevention.
* refactor: address review concerns for pickle fix
1. Remove deserialize_value() fallback in _deserialize_hitl_response
untrusted HITL data now returns as-is when no type hint is available,
never flowing into pickle.loads().
2. Move strip_pickle_markers() out of reconstruct_to_type() the function
is general-purpose again; untrusted-data callers are responsible for
sanitizing first (documented with NOTE comment).
3. Define _PICKLE_MARKER/_TYPE_MARKER as local constants with import-time
assertions against core's values decouples from private names while
failing loudly if core ever changes them.
4. Update tests to reflect new responsibility boundaries.
* fix: simplify warning message and fix ruff RUF001 lint
* fix: suppress pyright reportPrivateUsage on core marker imports
* Lower marker-strip log from warning to debug to avoid log flooding
* Replace assert with RuntimeError for marker sync checks (ruff S101)
* Fix pyright and ruff CI errors in security fix
- Use cast() for dict/list comprehensions in strip_pickle_markers (pyright)
- type: ignore for narrowed dict return in _workflow.py (pyright)
- Simplify marker imports: use core constants directly, remove local copies
- Remove duplicate pyright ignore comment
* Remove duplicate end-to-end test in TestStripPickleMarkers
* Suppress mypy redundant-cast on list cast needed by pyright
Tao ChenandGitHub
Ahmed MuhsinandGitHub
