1 Commits

• client: extend custom CA handling across HTTPS and websocket clients (#14239)

  ## Stacked PRs
  
  This work is now effectively split across two steps:
  
  - #14178: add custom CA support for browser and device-code login flows,
  docs, and hermetic subprocess tests
  - #14239: extend that shared custom CA handling across Codex HTTPS
  clients and secure websocket TLS
  
  Note: #14240 was merged into this branch while it was stacked on top of
  this PR. This PR now subsumes that websocket follow-up and should be
  treated as the combined change.
  
  Builds on top of #14178.
  
  ## Problem
  
  Custom CA support landed first in the login path, but the real
  requirement is broader. Codex constructs outbound TLS clients in
  multiple places, and both HTTPS and secure websocket paths can fail
  behind enterprise TLS interception if they do not honor
  `CODEX_CA_CERTIFICATE` or `SSL_CERT_FILE` consistently.
  
  This PR broadens the shared custom-CA logic beyond login and applies the
  same policy to websocket TLS, so the enterprise-proxy story is no longer
  split between “HTTPS works” and “websockets still fail”.
  
  ## What This Delivers
  
  Custom CA support is no longer limited to login. Codex outbound HTTPS
  clients and secure websocket connections can now honor the same
  `CODEX_CA_CERTIFICATE` / `SSL_CERT_FILE` configuration, so enterprise
  proxy/intercept setups work more consistently end-to-end.
  
  For users and operators, nothing new needs to be configured beyond the
  same CA env vars introduced in #14178. The change is that more of Codex
  now respects them, including websocket-backed flows that were previously
  still using default trust roots.
  
  I also manually validated the proxy path locally with mitmproxy using:
  `CODEX_CA_CERTIFICATE=~/.mitmproxy/mitmproxy-ca-cert.pem
  HTTPS_PROXY=http://127.0.0.1:8080 just codex`
  with mitmproxy installed via `brew install mitmproxy` and configured as
  the macOS system proxy.
  
  ## Mental model
  
  `codex-client` is now the owner of shared custom-CA policy for outbound
  TLS client construction. Reqwest callers start from the builder
  configuration they already need, then pass that builder through
  `build_reqwest_client_with_custom_ca(...)`. Websocket callers ask the
  same module for a rustls client config when a custom CA bundle is
  configured.
  
  The env precedence is the same everywhere:
  - `CODEX_CA_CERTIFICATE` wins
  - otherwise fall back to `SSL_CERT_FILE`
  - otherwise use system roots
  
  The helper is intentionally narrow. It loads every usable certificate
  from the configured PEM bundle into the appropriate root store and
  returns either a configured transport or a typed error that explains
  what went wrong.
  
  ## Non-goals
  
  This does not add handshake-level integration tests against a live TLS
  endpoint. It does not validate that the configured bundle forms a
  meaningful certificate chain. It also does not try to force every
  transport in the repo through one abstraction; it extends the shared CA
  policy across the reqwest and websocket paths that actually needed it.
  
  ## Tradeoffs
  
  The main tradeoff is centralizing CA behavior in `codex-client` while
  still leaving adoption up to call sites. That keeps the implementation
  additive and reviewable, but it means the rule "outbound Codex TLS that
  should honor enterprise roots must use the shared helper" is still
  partly enforced socially rather than by types.
  
  For websockets, the shared helper only builds an explicit rustls config
  when a custom CA bundle is configured. When no override env var is set,
  websocket callers still use their ordinary default connector path.
  
  ## Architecture
  
  `codex-client::custom_ca` now owns CA bundle selection, PEM
  normalization, mixed-section parsing, certificate extraction, typed
  CA-loading errors, and optional rustls client-config construction for
  websocket TLS.
  
  The affected consumers now call into that shared helper directly rather
  than carrying login-local CA behavior:
  - backend-client
  - cloud-tasks
  - RMCP client paths that use `reqwest`
  - TUI voice HTTP paths
  - `codex-core` default reqwest client construction
  - `codex-api` websocket clients for both responses and realtime
  websocket connections
  
  The subprocess CA probe, env-sensitive integration tests, and shared PEM
  fixtures also live in `codex-client`, which is now the actual owner of
  the behavior they exercise.
  
  ## Observability
  
  The shared CA path logs:
  - which environment variable selected the bundle
  - which path was loaded
  - how many certificates were accepted
  - when `TRUSTED CERTIFICATE` labels were normalized
  - when CRLs were ignored
  - where client construction failed
  
  Returned errors remain user-facing and include the relevant env var,
  path, and remediation hint. That same error model now applies whether
  the failure surfaced while building a reqwest client or websocket TLS
  configuration.
  
  ## Tests
  
  Pure unit tests in `codex-client` cover env precedence and PEM
  normalization behavior. Real client construction remains in subprocess
  tests so the suite can control process env and avoid the macOS seatbelt
  panic path that motivated the hermetic test split.
  
  The subprocess coverage verifies:
  - `CODEX_CA_CERTIFICATE` precedence over `SSL_CERT_FILE`
  - fallback to `SSL_CERT_FILE`
  - single-cert and multi-cert bundles
  - malformed and empty-file errors
  - OpenSSL `TRUSTED CERTIFICATE` handling
  - CRL tolerance for well-formed CRL sections
  
  The websocket side is covered by the existing `codex-api` / `codex-core`
  websocket test suites plus the manual mitmproxy validation above.
  
  ---------
  
  Co-authored-by: Ivan Zakharchanka <3axap4eHko@gmail.com>
  Co-authored-by: Codex <noreply@openai.com>

  Josh McKinney · 2026-03-13 00:59:26 +00:00
  6912da84a8