Files
hermes-agent/tests/tools/test_osv_check.py
Teknium 4494fba140 feat: OSV malware check for MCP extension packages (#5305)
Before launching an MCP server via npx/uvx, queries the OSV (Open Source
Vulnerabilities) API to check if the package has known malware advisories
(MAL-* IDs). Regular CVEs are ignored — only confirmed malware is blocked.

- Free, public API (Google-maintained), ~300ms per query
- Runs once per MCP server launch, inside _run_stdio() before subprocess spawn
- Parallel with other MCP servers (asyncio.gather already in place)
- Fail-open: network errors, timeouts, unrecognized commands → allow
- Parses npm (scoped @scope/pkg@version) and PyPI (name[extras]==version)

Inspired by Block/goose extension malware check.
2026-04-05 12:46:07 -07:00

171 lines
6.1 KiB
Python

"""Tests for OSV malware check on MCP extension packages."""
import json
import pytest
from unittest.mock import patch, MagicMock
from tools.osv_check import (
check_package_for_malware,
_infer_ecosystem,
_parse_package_from_args,
_parse_npm_package,
_parse_pypi_package,
_query_osv,
)
class TestInferEcosystem:
def test_npx(self):
assert _infer_ecosystem("npx") == "npm"
assert _infer_ecosystem("/usr/bin/npx") == "npm"
def test_uvx(self):
assert _infer_ecosystem("uvx") == "PyPI"
assert _infer_ecosystem("/home/user/.local/bin/uvx") == "PyPI"
def test_pipx(self):
assert _infer_ecosystem("pipx") == "PyPI"
def test_unknown(self):
assert _infer_ecosystem("node") is None
assert _infer_ecosystem("python") is None
assert _infer_ecosystem("/bin/bash") is None
class TestParseNpmPackage:
def test_simple(self):
assert _parse_npm_package("react") == ("react", None)
def test_with_version(self):
assert _parse_npm_package("react@18.3.1") == ("react", "18.3.1")
def test_scoped(self):
assert _parse_npm_package("@modelcontextprotocol/server-filesystem") == (
"@modelcontextprotocol/server-filesystem", None
)
def test_scoped_with_version(self):
assert _parse_npm_package("@scope/pkg@1.2.3") == ("@scope/pkg", "1.2.3")
def test_latest_ignored(self):
assert _parse_npm_package("react@latest") == ("react", None)
class TestParsePypiPackage:
def test_simple(self):
assert _parse_pypi_package("requests") == ("requests", None)
def test_with_version(self):
assert _parse_pypi_package("requests==2.32.3") == ("requests", "2.32.3")
def test_with_extras(self):
assert _parse_pypi_package("mcp[cli]==1.2.3") == ("mcp", "1.2.3")
def test_extras_no_version(self):
assert _parse_pypi_package("mcp[cli]") == ("mcp", None)
class TestParsePackageFromArgs:
def test_npm_skips_flags(self):
name, ver = _parse_package_from_args(["-y", "@scope/pkg@1.0"], "npm")
assert name == "@scope/pkg"
assert ver == "1.0"
def test_pypi_skips_flags(self):
name, ver = _parse_package_from_args(["--from", "mcp[cli]"], "PyPI")
# --from is a flag, mcp[cli] is the package
# Actually --from is a flag so it gets skipped, mcp[cli] is found
assert name == "mcp"
def test_empty_args(self):
assert _parse_package_from_args([], "npm") == (None, None)
def test_only_flags(self):
assert _parse_package_from_args(["-y", "--yes"], "npm") == (None, None)
class TestCheckPackageForMalware:
def test_clean_package(self):
"""Clean package returns None (allow)."""
mock_response = MagicMock()
mock_response.read.return_value = json.dumps({"vulns": []}).encode()
mock_response.__enter__ = lambda s: s
mock_response.__exit__ = MagicMock(return_value=False)
with patch("tools.osv_check.urllib.request.urlopen", return_value=mock_response):
result = check_package_for_malware("npx", ["-y", "@modelcontextprotocol/server-filesystem"])
assert result is None
def test_malware_blocked(self):
"""Known malware package returns error string."""
mock_response = MagicMock()
mock_response.read.return_value = json.dumps({
"vulns": [
{"id": "MAL-2023-7938", "summary": "Malicious code in evil-pkg"},
{"id": "CVE-2023-1234", "summary": "Regular vulnerability"}, # should be filtered
]
}).encode()
mock_response.__enter__ = lambda s: s
mock_response.__exit__ = MagicMock(return_value=False)
with patch("tools.osv_check.urllib.request.urlopen", return_value=mock_response):
result = check_package_for_malware("npx", ["evil-pkg"])
assert result is not None
assert "BLOCKED" in result
assert "MAL-2023-7938" in result
assert "CVE-2023-1234" not in result # regular CVEs filtered
def test_network_error_fails_open(self):
"""Network errors allow the package (fail-open)."""
with patch("tools.osv_check.urllib.request.urlopen", side_effect=ConnectionError("timeout")):
result = check_package_for_malware("npx", ["some-package"])
assert result is None
def test_non_npx_skipped(self):
"""Non-npx/uvx commands are skipped entirely."""
result = check_package_for_malware("node", ["server.js"])
assert result is None
def test_uvx_pypi(self):
"""uvx commands check PyPI ecosystem."""
mock_response = MagicMock()
mock_response.read.return_value = json.dumps({"vulns": []}).encode()
mock_response.__enter__ = lambda s: s
mock_response.__exit__ = MagicMock(return_value=False)
with patch("tools.osv_check.urllib.request.urlopen", return_value=mock_response) as mock_url:
check_package_for_malware("uvx", ["mcp-server-fetch"])
# Verify PyPI ecosystem was sent
call_data = json.loads(mock_url.call_args[0][0].data)
assert call_data["package"]["ecosystem"] == "PyPI"
assert call_data["package"]["name"] == "mcp-server-fetch"
class TestLiveOsvQuery:
"""Live integration test against the real OSV API. Skipped if offline."""
@pytest.mark.skipif(
not pytest.importorskip("urllib.request", reason="no network"),
reason="network required",
)
def test_known_malware_package(self):
"""node-hide-console-windows has a real MAL- advisory."""
try:
result = _query_osv("node-hide-console-windows", "npm")
assert len(result) >= 1
assert result[0]["id"].startswith("MAL-")
except Exception:
pytest.skip("OSV API unreachable")
@pytest.mark.skipif(
not pytest.importorskip("urllib.request", reason="no network"),
reason="network required",
)
def test_clean_package(self):
"""react should have zero MAL- advisories."""
try:
result = _query_osv("react", "npm")
assert len(result) == 0
except Exception:
pytest.skip("OSV API unreachable")