P0 — must-fix
- iron_proxy: emit default upstream_deny_cidrs (loopback, IMDS
169.254.0.0/16, RFC1918) when caller passes None. Honours the docs
promise that cloud-metadata IPs are refused regardless of allowlist.
- iron_proxy: bind 127.0.0.1 (+ docker0 bridge IP on Linux) instead of
INADDR_ANY (':9090'). LAN peers with a leaked sandbox token could
otherwise spend the operator's API quota against any allowlisted
upstream.
- ensure_ca_cert: write the CA private key via os.open(..., 0o600)
instead of shutil.copy2+os.chmod — closes the TOCTOU window where
the key existed under the default umask.
- discover_uncovered_providers + proxy.fail_on_uncovered_providers
config: refuse to start (when strict) if env vars for non-bearer
providers (Anthropic native x-api-key, AWS SigV4, Azure OpenAI,
etc.) are present. Surfaces a wizard warning in non-strict mode.
P1 — should-fix
- start_proxy: build a minimal subprocess env (PATH/HOME/locale +
only the env names referenced by mappings) instead of os.environ
.copy(). Strips proxy-recursion vars (HTTPS_PROXY etc.). Stops
the proxy's /proc/<pid>/environ from leaking every host secret
to same-uid local processes.
- start_proxy: optional Bitwarden refresh path
(refresh_secrets_from_bitwarden=True, bitwarden_config=...).
When credential_source=bitwarden, cmd_start wires it in — that's
what delivers the rotation guarantee the docs make.
- build_proxy_config: wire audit_log into the rendered yaml
(log.audit_path). Parameter was accepted but never used.
- ensure_audit_log: pre-create the audit log with 0o600 perms so
iron-proxy inherits tight permissions instead of relying on umask.
- Rename 'hermes proxy ...' → 'hermes egress ...' in user-facing
strings (docstring, RuntimeError messages, post-setup banner).
- start_proxy: open log file with 0o600 perms and close the parent
fd immediately after Popen — fixes the per-restart fd leak.
- DockerEnvironment: detect collisions between docker_env and the
egress-controlling env vars (HTTPS_PROXY, SSL_CERT_FILE, etc.).
When enforce_on_docker=true, fail loud rather than silently
inverting the isolation; when false, warn and let docker_env win.
- proxy_cli: merge_mappings preserves existing tokens on re-setup;
--rotate-tokens flag re-mints all of them. Stops re-running
`hermes egress setup` from invalidating tokens baked into
already-running sandboxes.
- proxy_cli: --from-bitwarden fail-loud on disabled BW config,
missing access token, or empty vault. Previously fell through to
the env path while still writing credential_source: bitwarden.
- docker.py: narrow `except Exception` → `except ImportError`;
iron_proxy._read_tunnel_port_from_config: same. Bare excepts
were masking real config-load bugs.
- start_proxy: write pidfile via os.open with O_NOFOLLOW + 0o600
+ st_uid check. Refuses to follow a pre-existing symlink at the
pidfile path.
- mint_proxy_token docstring: document the 128-bit suffix entropy
explicitly (sha256 truncated to 32 hex chars).
P2 — follow-up
- start_proxy: poll-with-timeout (100ms cadence on _port_listening)
instead of an unconditional 5s sleep. Saves several seconds per
Docker container create when enforce_on_docker=true.
- docker.py: apply enforce_on_docker semantics when CA file vanishes
between status.configured check and CA mount. Previously returned
empty args silently.
- docker.py: refuse to mount when mappings.json is empty/corrupt
(was indistinguishable from upstream outage from inside the
sandbox).
- install_iron_proxy: tarfile.extract(..., filter='data') to silence
the PEP 706 deprecation and opt into the 3.14+ default.
- _proxy_state_dir: chmod 0o700 unconditionally; add
_proxy_state_dir_ro() so read-only callers don't create the dir.
- stop_proxy: re-verify pid before SIGKILL via /proc/<pid>/stat
starttime AND _pid_alive. Prevents SIGKILL'ing a recycled pid.
- _pid_alive: tightened cmdline check — basename match on argv[0]
plus an in-process nonce env var ('iron-proxy' in cmdline matched
'tail iron-proxy.log' and editors with the log open).
- docker.py: NODE_OPTIONS=--use-openssl-ca so Node.js routes through
the OpenSSL CA store SSL_CERT_FILE controls, narrowing the
Python/curl-replace vs Node-add asymmetry waefrebeorn flagged.
P3 — polish
- proxy_cli: dest='egress_command' (was 'proxy_command' which
collided lexically with the inbound OAuth subparser).
- iron_proxy_version: cache by binary path — get_status is called
per Docker container create, version is constant per binary.
- Drop unused `import sys` from iron_proxy.
- proxy_cli: `is not None` check on --tunnel-port (was treating 0
as falsy and silently substituting the default).
- proxy_cli cmd_disable: use get_status().pid instead of reaching
into ip._read_pid() (stale pidfile from a crashed run would have
fired a spurious "still running" warning).
- Tests: replace hardcoded /tmp/ca.* paths with tmp_path-derived
fixtures so tests are hermetic across hosts.
CI
- Windows footguns scanner: os.kill(pid, 0) is now gated behind
platform.system() != 'Windows' with a windows-footgun: ok marker;
signal.SIGKILL falls back to SIGTERM on Windows via
getattr(signal, 'SIGKILL', signal.SIGTERM).
- docs MDX compilation: replace bare `<https://…>` URLs with
`[text](url)` syntax (MDX-jsx parser rejects the angle-bracket
form).
Tests
- 32 new tests covering default deny CIDRs, bind policy, audit log
wiring, subprocess env minimization, CA TOCTOU 0o600, state dir
0o700, empty-mappings refusal, CA-vanished refusal, docker_env
collision detection, token preservation/rotate, uncovered provider
detection, and the proxy_cli command handlers + argparse wiring.
- All 156 tests in test_iron_proxy + test_iron_proxy_cli +
test_docker_environment + test_config pass locally.
Acknowledged but not addressed in this revision
- E2E test for HTTPS CONNECT + TLS-MITM path: existing E2E exercises
plain HTTP; full MITM coverage needs separate CI infra (real iron-
proxy binary + curl with custom CA). Tracked as follow-up.
- Cosign-style supply-chain verification for the binary checksum:
upstream iron-proxy doesn't sign releases yet. Accepted pattern
(same as Bitwarden integration); tracked as follow-up.
- CA rotation CLI (`hermes egress rotate-ca`): scope-cut to a
follow-up.
Reviewers: @annguyenNous @waefrebeorn @GodsBoy @erhnysr
teknium1
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