## Stack
1. Parent PR: #18868 adds MITM hook config and model only.
2. This PR wires runtime enforcement.
3. User facing config follow up: #18240 moves MITM policy into the
PermissionProfile network tree.
## Why
1. After the hook model exists, the proxy needs a separate behavior
change that can be tested at the request path.
2. This PR makes hooked HTTPS hosts require MITM, evaluates inner
requests after CONNECT, mutates headers for matching hooks, and blocks
hooked hosts when no hook matches.
3. It also fixes the activation path so a permission profile with MITM
hook policy starts the managed proxy.
4. Keeping this separate from #18868 lets reviewers focus on runtime
effects, telemetry, and request mutation.
## Summary
1. Store compiled MITM hooks in network proxy state.
2. Require MITM for hooked hosts even when network mode is full.
3. Evaluate inner HTTPS requests against host specific hooks.
4. Apply hook actions by replacing request headers before forwarding.
5. Block hooked hosts when no hook matches and record block telemetry.
6. Treat profile MITM hook policy as managed proxy policy so the proxy
starts when needed.
7. Keep the duplicate authorization header replacement and query
preserving request rebuild in this runtime PR.
8. Add runtime tests and README guidance for hook enforcement.
## Validation
1. Ran the network proxy MITM policy tests.
2. Ran the hooked host CONNECT test.
3. Ran the authorization header replacement test.
4. Ran the core permission profile proxy activation test for MITM hooks.
5. Ran the scoped Clippy fixer for the network proxy crate.
6. Ran the scoped Clippy fixer for the core crate.
**PR Summary**
This PR adds embedded-only OTEL policy audit logging for
`codex-network-proxy` and threads audit metadata from `codex-core` into
managed proxy startup.
### What changed
- Added structured audit event emission in `network_policy.rs` with
target `codex_otel.network_proxy`.
- Emitted:
- `codex.network_proxy.domain_policy_decision` once per domain-policy
evaluation.
- `codex.network_proxy.block_decision` for non-domain denies.
- Added required policy/network fields, RFC3339 UTC millisecond
`event.timestamp`, and fallback defaults (`http.request.method="none"`,
`client.address="unknown"`).
- Added non-domain deny audit emission in HTTP/SOCKS handlers for
mode-guard and proxy-state denies, including unix-socket deny paths.
- Added `REASON_UNIX_SOCKET_UNSUPPORTED` and used it for unsupported
unix-socket auditing.
- Added `NetworkProxyAuditMetadata` to runtime/state, re-exported from
`lib.rs` and `state.rs`.
- Added `start_proxy_with_audit_metadata(...)` in core config, with
`start_proxy()` delegating to default metadata.
- Wired metadata construction in `codex.rs` from session/auth context,
including originator sanitization for OTEL-safe tagging.
- Updated `network-proxy/README.md` with embedded-mode audit schema and
behavior notes.
- Refactored HTTP block-audit emission to a small local helper to reduce
duplication.
- Preserved existing unix-socket proxy-disabled host/path behavior for
responses and blocked history while using an audit-only endpoint
override (`server.address="unix-socket"`, `server.port=0`).
### Explicit exclusions
- No standalone proxy OTEL startup work.
- No `main.rs` binary wiring.
- No `standalone_otel.rs`.
- No standalone docs/tests.
### Tests
- Extended `network_policy.rs` tests for event mapping, metadata
propagation, fallbacks, timestamp format, and target prefix.
- Extended HTTP tests to assert unix-socket deny block audit events.
- Extended SOCKS tests to cover deny emission from handler deny
branches.
- Added/updated core tests to verify audit metadata threading into
managed proxy state.
### Validation run
- `just fmt`
- `cargo test -p codex-network-proxy` ✅
- `cargo test -p codex-core` ran with one unrelated flaky timeout
(`shell_snapshot::tests::snapshot_shell_does_not_inherit_stdin`), and
the test passed when rerun directly ✅
---------
Co-authored-by: viyatb-oai <viyatb@openai.com>
This add a new crate, `codex-network-proxy`, a local network proxy
service used by Codex to enforce fine-grained network policy (domain
allow/deny) and to surface blocked network events for interactive
approvals.
- New crate: `codex-rs/network-proxy/` (`codex-network-proxy` binary +
library)
- Core capabilities:
- HTTP proxy support (including CONNECT tunneling)
- SOCKS5 proxy support (in the later PR)
- policy evaluation (allowed/denied domain lists; denylist wins;
wildcard support)
- small admin API for polling/reload/mode changes
- optional MITM support for HTTPS CONNECT to enforce “limited mode”
method restrictions (later PR)
Will follow up integration with codex in subsequent PRs.
## Testing
- `cd codex-rs && cargo build -p codex-network-proxy`
- `cd codex-rs && cargo run -p codex-network-proxy -- proxy`
evawong-oai