fix(gateway): fail-close Telegram auth when TELEGRAM_ALLOWED_USERS is empty; warn on ALLOW_ALL

[wesleysimplicio]

Problem

When TELEGRAM_ALLOWED_USERS is not set, TelegramAdapter._is_authorized_user() returns True — any Telegram account that discovers the bot gets full agent access (filesystem, terminal, GitHub credentials).

Additionally, there is no warning emitted when GATEWAY_ALLOW_ALL_USERS=true is active — the most dangerous open state passes silently.

Root cause

gateway/platforms/telegram.py:501:

allowed_csv = os.getenv("TELEGRAM_ALLOWED_USERS", "").strip()
if not allowed_csv:
    return True    # ← fails OPEN when env var is absent

gateway/run.py:3360: the startup warning only fires when not _any_allowlist and not _allow_all, so _allow_all=True produces no log output.

Fix

gateway/platforms/telegram.py — fail closed when no allowlist:

if not allowed_csv:
    _global_open = os.getenv("GATEWAY_ALLOW_ALL_USERS", "").lower() in ("true", "1", "yes")
    _tg_open = os.getenv("TELEGRAM_ALLOW_ALL_USERS", "").lower() in ("true", "1", "yes")
    return _global_open or _tg_open   # False unless operator explicitly opts in

gateway/run.py — loud warning when allow-all is active:

elif _allow_all:
    logger.warning(
        "SECURITY WARNING: Gateway is open to ALL users (*_ALLOW_ALL_USERS=true). ..."
    )

Tests

tests/gateway/test_telegram_auth_fail_closed.py (new, 6 tests):

Test	Assertion
test_no_allowlist_no_allow_all_denies	empty env → False
test_gateway_allow_all_permits	GATEWAY_ALLOW_ALL_USERS=true → True
test_telegram_allow_all_permits	TELEGRAM_ALLOW_ALL_USERS=1 → True
test_allowlist_match_permits	matching ID in CSV → True
test_allowlist_mismatch_denies	non-matching ID → False
test_wildcard_in_allowlist_permits_all	* in CSV → True

All 6 pass.

Visual

flowchart TD
    A[_is_authorized_user called] --> B{TELEGRAM_ALLOWED_USERS set?}
    B -- yes --> C{user_id in allowlist or *?}
    C -- yes --> D[return True]
    C -- no --> E[return False]
    B -- no --> F{GATEWAY_ALLOW_ALL_USERS or TELEGRAM_ALLOW_ALL_USERS?}
    F -- yes --> D
    F -- no --> E

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Closes #24457

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[alt-glitch]

Duplicate of #24468 (earliest open fix implementing fail-closed Telegram auth with GATEWAY_ALLOW_ALL_USERS check). Also competes with #24602 and #21356. All fix #24457.

[wesleysimplicio]

Closing in favor of #24468 (earliest open) per @alt-glitch's note — same fail-closed Telegram auth fix for #24457.