## 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.
## Why
The proxy checks the requested host before opening the upstream
connection, but DNS can resolve an allowed hostname to a loopback,
private, or other non-public address after that first decision. Without
a final check on the actual socket target, a request that looks
acceptable at the hostname layer can still connect to a local service
once resolution completes.
## What changed
- add a shared TCP connector check for direct proxy egress
- use that path for HTTP, `CONNECT`, SOCKS5, and MITM upstream
connections
- keep configured upstream proxy hops on the existing proxy path
- add direct-connector coverage for allowed and rejected local targets
## Security impact
Direct proxy egress now rechecks the resolved socket address before
connecting, closing the gap between hostname policy evaluation and the
final network target.
## Verification
- `cargo test -p codex-network-proxy`
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Co-authored-by: Codex <noreply@openai.com>
evawong-oai