hermes-agent/tests/tools/test_skill_view_traversal.py
Teknium 56f833efa4
fix(skills): block path traversal via skill_view name argument (#40566)
Closes #38643.

Salvaged from #40521; cleaned up, re-verified against main, tests added.

Co-authored-by: xy200303 <xy200303@users.noreply.github.com>
2026-06-06 18:29:52 -07:00

120 lines
5 KiB
Python

"""Tests for path traversal prevention in skill_view.
Regression tests for issue #220: skill_view file_path parameter allowed
reading arbitrary files (e.g., ~/.hermes/.env) via path traversal.
"""
import json
import pytest
from unittest.mock import patch
from tools.skills_tool import skill_view
@pytest.fixture()
def fake_skills(tmp_path):
"""Create a fake skills directory with one skill and a sensitive file outside."""
skills_dir = tmp_path / "skills"
skill_dir = skills_dir / "test-skill"
skill_dir.mkdir(parents=True)
# Create SKILL.md
(skill_dir / "SKILL.md").write_text("# Test Skill\nA test skill.")
# Create a legitimate file inside the skill
refs = skill_dir / "references"
refs.mkdir()
(refs / "api.md").write_text("API docs here")
# Create a sensitive file outside skills dir (simulating .env)
(tmp_path / ".env").write_text("SECRET_API_KEY=sk-do-not-leak")
with patch("tools.skills_tool.SKILLS_DIR", skills_dir):
yield {"skills_dir": skills_dir, "skill_dir": skill_dir, "tmp_path": tmp_path}
class TestPathTraversalBlocked:
def test_dotdot_in_skill_name_blocked(self, fake_skills):
"""A traversal skill name must not escape the skills search root.
Regression: `name` was joined onto each search dir to build the lookup
path with no `..`/absolute guard (while file_path WAS validated), so
name="../outside-skill" could select a sibling dir outside SKILLS_DIR.
"""
tmp_path = fake_skills["tmp_path"]
outside_skill = tmp_path / "outside-skill"
outside_skill.mkdir()
(outside_skill / "SKILL.md").write_text("# Outside Skill\n")
(outside_skill / ".env").write_text("ESCAPED_SECRET=do-not-leak")
result = json.loads(skill_view("../outside-skill", file_path=".env"))
assert result["success"] is False
assert "traversal" in result["error"].lower()
assert "do-not-leak" not in json.dumps(result)
def test_absolute_skill_name_blocked(self, fake_skills):
"""An absolute skill name must not bypass the trusted search root."""
tmp_path = fake_skills["tmp_path"]
outside_skill = tmp_path / "outside-absolute"
outside_skill.mkdir()
(outside_skill / "SKILL.md").write_text("# Outside Absolute\n")
(outside_skill / ".env").write_text("ABSOLUTE_SECRET=do-not-leak")
result = json.loads(skill_view(str(outside_skill), file_path=".env"))
assert result["success"] is False
assert "relative path" in result["error"].lower()
assert "do-not-leak" not in json.dumps(result)
def test_legit_skill_name_still_works(self, fake_skills):
"""A normal skill name must still resolve after the name guard."""
result = json.loads(skill_view("test-skill"))
assert result["success"] is True
def test_dotdot_in_file_path(self, fake_skills):
"""Direct .. traversal should be rejected."""
result = json.loads(skill_view("test-skill", file_path="../../.env"))
assert result["success"] is False
assert "traversal" in result["error"].lower()
def test_dotdot_nested(self, fake_skills):
"""Nested .. traversal should also be rejected."""
result = json.loads(skill_view("test-skill", file_path="references/../../../.env"))
assert result["success"] is False
assert "traversal" in result["error"].lower()
def test_legitimate_file_still_works(self, fake_skills):
"""Valid paths within the skill directory should work normally."""
result = json.loads(skill_view("test-skill", file_path="references/api.md"))
assert result["success"] is True
assert "API docs here" in result["content"]
def test_no_file_path_shows_skill(self, fake_skills):
"""Calling skill_view without file_path should return the SKILL.md."""
result = json.loads(skill_view("test-skill"))
assert result["success"] is True
def test_symlink_escape_blocked(self, fake_skills):
"""Symlinks pointing outside the skill directory should be blocked."""
skill_dir = fake_skills["skill_dir"]
secret = fake_skills["tmp_path"] / "secret.txt"
secret.write_text("TOP SECRET DATA")
symlink = skill_dir / "evil-link"
try:
symlink.symlink_to(secret)
except OSError:
pytest.skip("Symlinks not supported")
result = json.loads(skill_view("test-skill", file_path="evil-link"))
# The resolve() check should catch the symlink escaping
assert result["success"] is False
assert "escapes" in result["error"].lower() or "boundary" in result["error"].lower()
def test_sensitive_file_not_leaked(self, fake_skills):
"""Even if traversal somehow passes, sensitive content must not leak."""
result = json.loads(skill_view("test-skill", file_path="../../.env"))
assert result["success"] is False
assert "sk-do-not-leak" not in result.get("content", "")
assert "sk-do-not-leak" not in json.dumps(result)