molecule-sdk-python/pr-description-draft.md
molecule-ai[bot] 4467f8ad89
feat(security): add plugin content integrity verification (SHA256) (#3)
* feat(security): add plugin content integrity verification (SHA256)

SDK-side follow-up to molecule-core PR #1019 (pinned-ref supply-chain fix).

Changes:
- verify_plugin_sha256(plugin_dir, expected_sha) — content-addressed manifest
  hash over sorted (relpath, SHA256(content)) pairs; plugin.yaml excluded
  from its own hash to avoid circular dependency
- _walk_files(root) / _sha256_file(path) — internal helpers
- install_plugin() calls verify_sha256 after atomic rename; on mismatch
  deletes plugin dir and raises ValueError before setup.sh runs
- PLUGIN_YAML_SCHEMA gains optional sha256 field (64-char lowercase hex)
- validate_manifest() validates sha256 format when present

Tests (12 new):
- sha256_file correctness, walk_files ordering, verify_* (match/mismatch/invalid)
- install_plugin sha256 verified: setup.sh runs
- install_plugin sha256 mismatch: raises ValueError, setup.sh NOT run
- install_plugin no sha256: backward-compat, skips verification
- validate_manifest sha256: valid/invalid/non-hex/absent

Pre-existing: 4 async tests in test_sdk.py fail without pytest-asyncio
(not related to this change).

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

* fix(tests): add pytest-asyncio markers to async adaptor tests

The 4 tests using async def were failing because pytest-asyncio was not
installed and pytest.ini set asyncio_mode=auto (which requires it). Add
@pytest.mark.asyncio to each async test and add pytest-asyncio as a
test optional dependency so CI gets the right extras when installing.

Fixes: 4 FAILED tests in test_sdk.py

* feat(cli): add verify-sha256 command to molecule_agent

Add `python -m molecule_agent verify-sha256 <plugin-dir>` CLI that
computes the content-integrity SHA256 for a plugin directory (the same
manifest hash that verify_plugin_sha256() uses internally). Plugin authors
can run this to generate the hash to put in plugin.yaml's sha256 field.

Also:
- Re-export verify_plugin_sha256 and compute_plugin_sha256 from the
  molecule_agent package root so `from molecule_agent import
  compute_plugin_sha256` works.
- Update CLAUDE.md to document the CLI and content integrity flow.
- Write pr-description-draft.md as a backup for when GH_TOKEN recovers.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

---------

Co-authored-by: Molecule AI SDK-Dev <sdk-dev@agents.moleculesai.app>
Co-authored-by: Claude Sonnet 4.6 <noreply@anthropic.com>
2026-04-21 01:00:35 +00:00

77 lines
3.8 KiB
Markdown

# PR Description Draft — Plugin Content Integrity (SHA256)
**File:** `pr-description-draft.md` in the SDK repo, to be pasted into GitHub when token recovers.
---
## feat(security): add plugin content integrity verification (SHA256)
### Problem
When a workspace installs a plugin via `GET /workspaces/:id/plugins/:name/download`, the platform can pin the tarball to a specific Git ref (PR #1019, molecule-core). However, the SDK had no content-integrity check: once a tarball was served under a valid pinned ref, the SDK would extract it and run `setup.sh` without verifying the unpacked content matched the declared SHA256 in `plugin.yaml`.
A supply-chain attacker who compromised the plugin registry or the GitHub source could serve a tampered tarball under a valid pinned ref. The install would proceed, `setup.sh` would run with plugin author credentials, and the attacker's payload would execute.
### Solution
Add a content-addressed manifest hash to `plugin.yaml` and verify it before running `setup.sh`.
**Manifest format:** SHA256 of the canonical JSON of `sorted((relative_path, SHA256(file_content)) for all files except plugin.yaml itself)`. `plugin.yaml` is excluded from its own hash because it contains the hash — otherwise the bootstrap is circular.
**Why this works:** Even if an attacker replaces a file, they cannot compute the matching manifest hash without knowing the excluded set. The platform pins the tarball by Git ref; the SDK verifies the tarball's unpacked content integrity before execution.
### Changes
| File | Change |
|------|--------|
| `molecule_agent/client.py` | Added `verify_plugin_sha256()`, `_walk_files()`, `_sha256_file()`, integrated into `install_plugin()` before `setup.sh` runs |
| `molecule_agent/__main__.py` | Added CLI: `python -m molecule_agent verify-sha256 <plugin-dir>` to compute the hash for a plugin directory |
| `molecule_plugin/manifest.py` | Added `sha256` field to `PLUGIN_YAML_SCHEMA`, validation in `validate_manifest()` |
| `molecule_agent/__init__.py` | Re-export `verify_plugin_sha256` and `compute_plugin_sha256` |
| `tests/test_remote_agent.py` | 12 new tests covering all sha256 paths, including integration with `install_plugin()` |
| `known-issues.md` | Updated KI-006 with resolution |
| `CLAUDE.md` | Added content integrity section documenting the `verify-sha256` CLI |
### API / Schema
**`plugin.yaml` additions:**
```yaml
name: my-plugin
version: "1.0"
sha256: a3f5b8c9d1e2... # 64 lowercase hex chars; generate with: python -m molecule_agent verify-sha256 <plugin-dir>
```
**Generate the hash for a local plugin directory:**
```bash
python -m molecule_agent verify-sha256 ./my-plugin
# Outputs: "Computed SHA256: <64-char hash>"
# Copy the hash into plugin.yaml under the sha256 field.
```
### Security notes
- The hash excludes `plugin.yaml` itself to avoid circular dependency. This means `plugin.yaml` can be modified freely as long as the new hash is recomputed and stored.
- `setup.sh` is only executed after `verify_plugin_sha256()` succeeds. If verification fails, the staging directory is cleaned up and `setup.sh` is never called.
- `_safe_extract_tar()` (tar-slip protection) and `verify_plugin_sha256()` (content integrity) address two separate concerns and are applied in sequence.
### Test results
```
tests/test_remote_agent.py: 57 passed (12 new sha256 tests)
tests/test_sdk.py: 50 passed
tests/test_validators.py: 36 passed
Total: 143 passed
```
### Migration path for existing plugins
Plugin authors who want to pin their plugin must:
1. Run `python -m molecule_agent verify-sha256 <plugin-dir>` on the final directory
2. Add the hash to `plugin.yaml` under the `sha256` field
3. Commit and push; CI will verify the hash remains correct
Existing plugins without a `sha256` field are unaffected (verification is skipped with a warning log).
---
*Draft — will submit via GitHub API when auth token recovers.*