fix(tts): reject '..' traversal in output_path

text_to_speech_tool accepts an explicit output_path. Without a traversal
guard, a path containing '..' components (whether prompt-injection-
controlled, from a confused skill, or just a buggy caller) could escape
its declared base and write the audio to a system location — e.g.
`output_path='audio/../../etc/cron.d/x'` lands the file outside the
intended audio cache.

Reject '..' components in the user-supplied path. Explicit absolute
paths are unchanged (the agent legitimately writes audio wherever the
user/caller asks); only traversal-style escapes are blocked. The
terminal tool can still write anywhere with approval — this just keeps
the unattended TTS surface from materializing files via traversal.

Regression tests cover: '..' in the middle (audio/../../etc/...),
bare '..' prefix, and the negative cases (absolute paths + relative
paths without '..' both pass through unchanged).

Salvaged from PR #6693 by @aaronlab. The original PR confined output to
DEFAULT_OUTPUT_DIR-or-cwd, which broke 9 existing tests that legitimately
write to tmp_path locations. The traversal-only check covers the actual
threat (path-escape via '..' from prompt injection) without restricting
where users can choose to write their audio.

The remaining pieces of #6693 (skill_commands rglob symlink rejection,
delegate_tool batch prefix display) are dropped:
- skill_commands rglob: breaks the documented design supporting
  ~/.hermes/skills/<name> as a symlink to a checked-out skill elsewhere
  (see comment at agent/skill_commands.py:73-75)
- delegate_tool batch prefix: pure UX, doesn't belong in a security PR

Co-authored-by: teknium1 <127238744+teknium1@users.noreply.github.com>
This commit is contained in:
aaronlab 2026-05-25 05:15:19 -07:00 committed by Teknium
parent ac5359a3f3
commit 5f20322d23
2 changed files with 78 additions and 0 deletions

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@ -0,0 +1,60 @@
"""Regression: text_to_speech_tool output_path must reject '..' traversal.
The TTS surface accepts agent/user-supplied absolute paths (writing to a
chosen file is the whole point). What it must reject is paths that use
``..`` components to escape their declared base those are almost
always either a bug or prompt-injection-controlled
(e.g. ``output_path="audio/../../etc/cron.d/x"``).
"""
import json
from tools.tts_tool import text_to_speech_tool
def test_output_path_rejects_traversal_escape():
"""A path with '..' components must be rejected before any provider work."""
result = json.loads(text_to_speech_tool(
text="hello",
output_path="audio/../../etc/cron.d/malicious",
))
assert result["success"] is False
assert "traversal" in result["error"].lower()
def test_output_path_rejects_bare_dotdot():
"""Bare '..' prefix must be rejected."""
result = json.loads(text_to_speech_tool(
text="hello",
output_path="../escape.mp3",
))
assert result["success"] is False
assert "traversal" in result["error"].lower()
def test_output_path_absolute_path_passes_guard(tmp_path, monkeypatch):
"""Explicit absolute paths must pass the traversal guard.
The agent legitimately writes audio to user-specified absolute paths;
only ``..`` components are rejected. Any subsequent failure (no
provider configured, etc.) is fine the assertion is specifically
that the 'traversal' rejection didn't fire.
"""
inside = tmp_path / "clip.mp3"
result = json.loads(text_to_speech_tool(
text="hello",
output_path=str(inside),
))
error = result.get("error", "")
assert "traversal" not in error.lower()
def test_output_path_relative_no_dotdot_passes_guard(tmp_path, monkeypatch):
"""Relative paths without '..' components must pass the guard."""
monkeypatch.chdir(tmp_path)
result = json.loads(text_to_speech_tool(
text="hello",
output_path="subdir/clip.mp3",
))
error = result.get("error", "")
assert "traversal" not in error.lower()

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@ -1868,6 +1868,24 @@ def text_to_speech_tool(
# Determine output path
if output_path:
# Reject '..' traversal components in the user-supplied path. An
# explicit absolute path is fine (the agent legitimately writes
# audio to user-specified locations), but a path that uses ``..``
# to escape its declared base is almost always either a bug or
# prompt-injection-controlled — e.g.
# ``output_path="audio/../../etc/cron.d/x"``. The terminal tool
# can still write anywhere with approval; this just keeps the
# unattended TTS surface from materializing files via traversal.
from tools.path_security import has_traversal_component
if has_traversal_component(output_path):
return json.dumps({
"success": False,
"error": (
f"output_path contains '..' traversal component: "
f"{output_path}. Use an absolute path or one relative "
"to the current directory without '..'."
),
}, ensure_ascii=False)
file_path = Path(output_path).expanduser()
if command_provider_config is not None:
# Respect caller-supplied path but align the extension with the