Files
hermes-agent/tools
rrevenanttt a81b519d41 fix(security): close hardline rm bypass via quoted paths and ${HOME}
## What does this PR do?

Closes a critical hole in the hardline command floor. HARDLINE_PATTERNS is
the unconditional last line of defense: detect_hardline_command runs BEFORE
every yolo / approvals.mode=off / cron approve-mode bypass, so it is the only
gate standing between the agent (or a prompt-injected instruction) and an
irrecoverable disk wipe. The three rm rules anchored on a bare path token,
and _normalize_command_for_detection never strips shell quotes — so the
ordinary, recommended shell idioms slipped straight through:

  rm -rf "/"        rm -rf '/'        rm -rf "/etc"
  rm -rf "$HOME"    rm -rf ${HOME}    rm -rf "${HOME}"

All of these returned NO hardline match. A leading quote pushes the path out
of reach of the flag group, a trailing quote breaks the `(\s|$)` terminator,
and the `${HOME}` brace form was never listed at all. Under --yolo,
approvals.mode=off, or cron approve-mode the dangerous-command layer is also
skipped, so these commands reached execution with zero gate — exactly the
unrecoverable data loss the floor is documented to make impossible. Because
quoting paths and `${HOME}` are normal shell usage, not exotic obfuscation,
this is a high-severity, easily-triggered bypass.

The fix makes the rm path matcher quote- and brace-tolerant while staying
conservative: a path is matched when it is either fully wrapped in its own
matching quote pair (`"/"`) or bare with a whitespace/end terminator. The
matching-quote requirement is deliberate so the change adds no new false
positives — a dangerous-looking string that is merely an argument to another
command (e.g. `git commit -m "rm -rf /"`) has a closing quote but no opening
quote of its own around the path, so neither branch fires.

## Related Issue

N/A

## Type of Change

- [x] 🔒 Security fix

## Changes Made

- `tools/approval.py`: added `_hardline_rm_path()` (matches a destructive
  path either fully quoted or bare-with-terminator), factored the protected
  system-dir list into `_HARDLINE_SYSTEM_DIRS` and the rm flag prefix into
  `_RM_FLAG_PREFIX`, and rebuilt the three rm `HARDLINE_PATTERNS` on top of
  them, adding the `${HOME}` brace form. Kept as plain concatenation so regex
  backslashes never land inside an f-string field (Python 3.11 floor).
- `tests/tools/test_hardline_blocklist.py`: added quoted (`"/"`, `'/'`,
  `"/etc"`, `"$HOME"`, ...) and brace (`${HOME}`, `"${HOME}"`) cases to the
  must-block set, a dedicated `_QUOTED_BRACE_BYPASS` regression parametrization,
  no-false-positive guards (`git commit -m "rm -rf /"`), and extended the
  yolo-cannot-bypass integration test to cover the quoted/brace forms.

## How to Test

1. Reproduce the bypass on `main`: `detect_hardline_command('rm -rf "/"')`
   returns `(False, None)` — the floor lets it through.
2. With this change it returns `(True, "recursive delete of root filesystem")`;
   the same holds for `'/'`, `"/etc"`, `"$HOME"`, `${HOME}`, `"${HOME}"`.
3. Run the suite: `scripts/run_tests.sh tests/tools/test_hardline_blocklist.py`
   — 125 passed, including the new bypass and no-false-positive cases.

## Checklist

### Code

- [x] I've read the Contributing Guide
- [x] My commit messages follow Conventional Commits (`fix(scope):`, etc.)
- [x] I searched for existing PRs to make sure this isn't a duplicate
- [x] My PR contains **only** changes related to this fix (no unrelated commits)
- [x] I've run the relevant tests and they pass
- [x] I've added tests for my changes (required for bug fixes)
- [x] I've tested on my platform: macOS 15 (Darwin 25.5)

### Documentation & Housekeeping

- [x] I've updated relevant documentation (README, `docs/`, docstrings) — or N/A
- [x] I've updated `cli-config.yaml.example` if I added/changed config keys — or N/A
- [x] I've updated `CONTRIBUTING.md` or `AGENTS.md` if I changed architecture or workflows — or N/A
- [x] I've considered cross-platform impact (Windows, macOS) — pattern-only change, ruff + footgun gate pass
- [x] I've updated tool descriptions/schemas if I changed tool behavior — or N/A
2026-07-01 01:25:24 -07:00
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2026-06-25 12:38:33 -07:00