## 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
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