Two live failures on the same guard (cron/lifecycle_guard.py), both of
which blocked legitimate diagnostics from inside the gateway:
1. Crash class: the referenced-script walk read compiled binaries as if
they were shell scripts. Reading/inspecting a referenced file is now
best-effort by construction: executable magic numbers (ELF, PE,
Mach-O fat/thin) short-circuit before any full read via a 4KB sniff,
NUL-bearing heads are skipped as non-scripts, and unreadable paths of
every kind (NUL bytes in the token, ENAMETOOLONG, missing files)
degrade to "nothing to scan" instead of raising. A second fail-safe
layer wraps the pure-string fallback so the boundary function stays
total even if the tokenizer itself fails.
2. False-positive class: the lifecycle regex matched its command shapes
inside DATA arguments — SQL string literals passed to sqlite3/psql
and grep/rg/journalctl patterns hunting for the lifecycle string in
logs. Added a fail-closed second-pass exemption: on a raw regex hit,
re-scan with data-sink executables' arguments masked; only a match
that survives (i.e. sits in command position) blocks. Masking is
skipped for pipes into shells/xargs, command/process substitution,
sqlite3 dot-commands and psql backslash escapes, so it can only ever
allow, never miss.
Behavioral tests: exact live false-positive shapes as negatives, the
smuggling shapes as positives, the kill-primitive positive catalog
unchanged, and an adversarial never-raises suite (NUL bytes, non-UTF-8,
/dev/*, directories, missing files, magic-prefix binaries).
3-reviewer simplify pass (reuse/quality/efficiency) findings:
- cron/scheduler.py _run_job_script: the ORIGINAL that
lifecycle_guard._resolve_script_path documents mirroring had the exact
same unguarded expanduser() — a NUL-bearing script value survives
creation (the guard treats it as nothing-to-scan) and crashed the
scheduler at fire time with ValueError instead of a clean job failure.
Same ingestion contract applied; regression test added.
- lifecycle_guard._resolve_script_path: get_hermes_home() -> Path.home()
raises RuntimeError when neither HERMES_HOME nor HOME resolves
(arbitrary-UID containers); the cron entry point called it bare.
Caught -> None; totality test added.
- terminal_tool: stale 'cat ...' docstring updated to the bounded
head -c form.
- lifecycle_guard: dead 'script_text and' condition dropped (guarded by
'if not script_text: continue' directly above).
Efficiency reviewer: no material findings (measured — encode/expand
costs negligible vs walk I/O, no timing regression vs base).
- _sanitize_remote_script_text: compare re-encoded BYTES against the cap,
not characters — a >1MiB multibyte file truncated at the head -c byte
bound decodes to fewer chars than bytes and would have scanned the
truncated text instead of failing closed (the exact local/remote
divergence this PR closes).
- terminal_tool: replace the three hardcoded 1MiB literals with
lifecycle_guard._MAX_REFERENCED_SCRIPT_BYTES so the budget cannot
drift; use the redirect-safe 'head -c N < path' form from
tools/image_source.py so leading-dash paths stay out of argv.
- Public guard wrapper: drop the duplicate depth-0 direct scan — the
walk already runs it; the except-path now falls back to the pure
string scans, preserving the direct verdict when the walk crashes.
The guard feeds untrusted byte streams (tokenized binaries, remote cat
output) into OS-path and shell-text operations; every incident so far
(#76762, #77703, #77780, #78256, #77729) was hot-fixed with an except at
whichever frame crashed that week. tilllt's regression suite on #79454
showed 4 members of the class still open on merged main. Close the class
at three boundaries instead:
- _expand_candidate_path(): single ingestion chokepoint for path
candidates — reject NUL/empty tokens before any Path OS call and
tolerate ValueError/RuntimeError/OSError from expanduser (T1/T2, plus
the HOME-unset launchd crash). Both _resolve_terminal_script_path and
_resolve_script_path now go through it.
- _sanitize_remote_script_text(): apply the local-read contract (NUL =
binary = nothing to scan; >1MiB = fail closed) to whatever any
read_remote_script callback returns, at the recursion boundary — the
guard stops trusting its callbacks (T3/T4).
- contains_gateway_lifecycle_command_or_referenced_script() is now total
by construction: direct regex scans (pure string ops) run first; the
best-effort filesystem walk is wrapped so an unexpected failure logs a
warning and falls back to the direct-scan verdict instead of killing
every terminal command until gateway restart.
terminal_tool's remote fallback also bounds the read at the source
(head -c 1MiB+1 instead of cat), so a 166MB ELF never crosses the wire —
the superlinear-shlex 30-minute stall from #79838's field report drops
to a 0.02s fail-closed verdict.
Regression tests: tilllt's T1-T4 adopted verbatim, plus an adversarial
never-raises sweep (NUL paths, unset HOME, over-long paths) and a
walk-crash fallback test.
The gateway terminal guard crashed with 'ValueError: embedded null byte'
(command never ran, exit_code -1) when a command invoked an ELF binary by
full path. _read_referenced_script correctly rejects the binary locally
(NUL in first chunk), but the read_remote_script fallback
(_read_script_in_env) then re-read the SAME file's bytes without a NUL
guard, decoded them, and fed machine code back into the scanner, which
re-tokenized it into a bogus NUL-bearing path and crashed at os.open.
- _read_script_in_env: skip content containing a NUL byte on both the
local-read and remote-cat branches (mirrors _read_referenced_script:
a binary is nothing to scan), so binary never re-enters the guard.
- _read_referenced_script: tolerate ValueError from os.open on a
NUL-in-path, alongside the existing OSError guard, so the guard can
never crash the terminal tool regardless of input.
Extends the #76762 NUL-safety fix (local path only) to the gateway's
remote-read fallback path.
On Linux, /usr/bin/python3 is >1MB, so the size check fired before
the NUL check could run — the binary was returned as unsafe=True
(blocked) instead of (None, False) (skip). Reorder: read the bounded
chunk first, check for NUL bytes (binary → skip), then check size
(oversized text → fail closed).
The gateway lifecycle guard (cron/lifecycle_guard.py) applied shell-style
tokenization and script-reference resolution to non-shell content, with two
regressions:
#77131 - every .py cron script using pathlib division was hard-blocked:
Path.home() / ".hermes" / ".env" tokenizes the bare "/" operator as an
executable path, which resolves to the filesystem root; the regular-file
check then fails closed as unsafe. Since Python runs under the
interpreter, never through a POSIX shell, the shell-script reference walk
is a false-positive generator on Python sources. check_gateway_lifecycle
now skips the walk for *.py scripts (the direct command regex still scans
the full text), and _iter_referenced_shell_scripts skips pure-separator
tokens.
#76762 - terminal commands invoking a binary by absolute path (e.g.
/usr/bin/python3) crashed the guard with ValueError: embedded null byte:
the walk read the binary's bytes, decoded them as text, and re-tokenized
machine code; the recursion then hit Path.resolve() on a NUL-bearing
path while only OSError was caught. _read_referenced_script now skips
NUL-containing files (binaries are not referenced shell scripts) and
resolve() tolerates ValueError.
Shell scripts (.sh/.bash/.zsh) keep the full deep scan; literal lifecycle
commands in .py scripts are still blocked by the direct regex. New tests
cover all four behaviors.
Extends the shared _GATEWAY_LIFECYCLE_PATTERN (used by BOTH the cron
creation-time guard in cron/lifecycle_guard.py and the terminal
execution-time hard-block in tools/terminal_tool.py) so Branch B covers
launchctl submit and bootstrap alongside kickstart/unload/load/stop/
restart, and normalizes POSIX shell line continuations before matching
so the exact multi-line reported shape in #62891 cannot slip past.
Also extends the execution-aware, label-independent detector
(contains_launchctl_submit_command, cherry-picked from #63272) to cover
launchctl bootstrap, since a neutral label like ai.hermes.svc-reload-tmp
defeats any label-anchored regex — the second production reproduction.
Regression tests cover both sites, including
`launchctl submit -l com.foo -- /path/gateway` and the bootstrap
variant, plus outside-gateway pass-through.
Branch B regex extension and continuation normalization drawn from
PR #62896; bootstrap coverage and test shapes drawn from PR #51003.
Co-authored-by: JackJin <1037461232@qq.com>
Co-authored-by: joelbrilliant <joelbrilliant1@gmail.com>
- Resolve guard cwd against get_session_cwd(session_key); fall back to env.cwd
when no session record exists yet, matching current main's per-session cwd
architecture.
- Make referenced-script reads backend-aware: local read first; if missing,
fall back to env.execute('cat ...') for SSH/Modal/Daytona backends.
- Reuse the recursive scanner in check_gateway_lifecycle so nested cron
wrapper scripts are caught, and resolve relative refs inside a script
against that script's directory.
- Add regression tests for remote-backend reads, two-session cwd, and nested
cron wrappers.
Verification: 80 passed tests/hermes_cli/test_gateway_restart_loop.py;
694 passed tests/cron; ruff + git diff --check clean.
Completes the #30719 restart-loop defenses. Defenses 1-2 (the
_HERMES_GATEWAY guard on `hermes gateway stop|restart` + terminal_tool,
and the cron-creation lifecycle filter) already landed on main, but two
gaps remained:
- The agent's `cronjob` model tool calls cron.jobs.create_job directly,
bypassing the hermes_cli.cron.cron_create CLI filter, so lifecycle
commands scheduled via the model tool were only blocked at execution
time (terminal_tool), not at creation. Moved the filter to a shared
cron/lifecycle_guard.py enforced at create_job — the single chokepoint
every job-creation path hits (CLI + model tool). Re-exported
_contains_gateway_lifecycle_command from hermes_cli.cron so
terminal_tool's import keeps working.
- No breaker for the auto-resume loop itself. Defenses 1-2 cover the
cron/CLI/terminal paths, but any other SIGTERM source (e.g. a raw
terminal("launchctl kickstart ai.hermes.gateway")) still triggers the
boot->auto-resume->re-run cycle. Added gateway/restart_loop_guard.py:
counts restart-interrupted boots in a rolling window (config
gateway.restart_loop_guard, default 3 boots / 60s) and skips
auto-resume for that boot once tripped. The gateway still comes up and
serves real inbound messages; it just stops replaying the session that
keeps killing it, putting a human back in the loop.
Also tightened the lifecycle regex over main's version: dropped
`hermes gateway start` (benign), required the gateway identifier on the
launchctl/systemctl branches (so `launchctl unload
ai.hermes.update-checker.plist` and `systemctl restart
hermes-meta.service` no longer false-positive), added the inverse
pkill token order, and fixed the binary-script bypass (decode with
errors='replace' instead of swallowing UnicodeDecodeError). The
create_job guard resolves relative script paths under HERMES_HOME/scripts
the same way the scheduler does, so a bare script name is scanned as the
file that actually runs.
Design and much of defense-2 originate from PR #33395 (@kshitijk4poor),
which itself salvaged #30728 (@SimoKiihamaki). Rebuilt against current
main since defenses 1-2 had already landed under different names.
Closes#30719.
Co-authored-by: SimoKiihamaki <simo.kiihamaki@gmail.com>
Co-authored-by: kshitijk4poor <82637225+kshitijk4poor@users.noreply.github.com>
Teknium
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