提出 #862542: nearai IronClaw 0.29.1 Authentication Bypass Using an Alternate Path or Channel (CWE-288)

# Technical Details
A Shell Approval Bypass via Newline-Chained Commands exists in the `classify_command_risk()` method in `src/tools/builtin/shell.rs` of IronClaw.

The application fails to split command chains on newline characters before classifying risk. The risk classifier splits on `|`, `&`, and `;` but not on `\n`, while the execution sink passes the original payload to `sh -c`, which treats newline as a command separator. When `shell` is set to `always_allow`, a payload like `echo control\nrm -rf ...` is classified from the benign `echo` prefix and auto-approved, while the equivalent semicolon-delimited destructive command is correctly classified as high risk and blocked.

# Vulnerable Code
File: src/tools/builtin/shell.rs
Method: classify_command_risk() — splits on ['|', '&', ';'] but not '\n'; matches_command_pattern() uses the first token only
Why: The classifier's segment split set does not include newline, so the second destructive command on a new line is invisible to risk analysis, yet the shell executor runs both lines through `sh -c`.

# Reproduction
1. Deploy IronClaw with `shell=always_allow` in the session permission state.
2. Send a shell command with a newline-chained destructive payload: `echo control\nrm -rf newline_canary_dir/*`.
3. Observe the gate decision is `allow`, the command executes, and the canary directory is deleted.
4. Confirm the semicolon equivalent `echo control; rm -rf ...` is correctly blocked with `gate_decision=pause`.

# Impact
- Approval bypass allowing destructive shell commands to execute without explicit per-invocation confirmation.
- Can lead to unauthorized file deletion, file modification, and follow-on command execution within the host or container context.
- Smuggles destructive behavior past the safety gate through invisible command boundaries.

• ソース: ⚠️ https://github.com/nearai/ironclaw/issues/4861
• ユーザー: Erichen-apple (UID 99087)
• 送信: 2026年06月18日 08:37 (2 月 ago)
• モデレーション: 2026年08月05日 18:45 (2 months later)
• ステータス: 承諾済み
• VulDBエントリ: 386265 [nearai ironclaw 迄 0.29.1 shell.rs classify_command_risk 特権昇格]
• ポイント: 20