This PR hardens the terminal tool's hardcoded security rules for
destructive commands like `rm -rf /`, and adds path normalization to
prevent traversal-based bypasses.
## Path normalization
Adds `normalize_path` which resolves `..`, `.`, and redundant path
separators, and `decide_permission_for_path` which checks permissions
against both raw and normalized paths (taking the most restrictive
result). This prevents attacks like `rm -rf /tmp/../../` which
previously bypassed the `rm -rf /` rule.
## rm command expansion
Adds `expand_rm_to_single_path_commands` which splits multi-argument rm
commands into individual single-path commands for checking. This catches
cases like `rm -rf /tmp /` where the dangerous path is the second
argument.
## Regex hardening
- **FLAGS**: Now accepts digits, underscores, and uppercase in long
flags (e.g. `--no-preserve-root`)
- **`--flag=value`**: Correctly matched as a single flag token
- **Trailing flags**: Handles GNU rm's acceptance of flags after path
operands (e.g. `rm / -rf`)
- **`--` marker**: Detects end-of-options bypass attempts (e.g. `rm -rf
-- /`)
- **Whitespace**: Handles tabs and other whitespace, not just spaces
## `$HOME`/`${HOME}` handling
Normalizes the suffix after `$HOME`/`${HOME}` variable references so
that traversal attacks like `rm -rf $HOME/./` or `rm -rf ${HOME}/foo/..`
are correctly detected.
Release Notes:
- Strengthened terminal security rules to detect path traversal attacks
in destructive commands like `rm -rf`.
Richard Feldman
7fa4cfcfed