Addresses all 9 findings from the review on PR #758:
Blocking:
- _revoke_refresh_token_at_idp now reads config from oauth_ctx["config"]
(the production-shaped nested dict). Previously read flat keys, causing
IdP revocation to silently no-op in production. Test fixtures rebuilt
to the realistic nested shape so the bug can't regress unnoticed.
- HTML error responses in oauth_login_callback now wrap IdP-controlled
error_body, str(e), and the attacker-controlled error/error_description
query params in html_escape. New test_browser_oauth_xss.py pins this.
Important:
- New _safe_next_url helper validates the ?next= query param at write
time (oauth_login), in oauth_logout, and on read from the session row
in oauth_login_callback. Blocks https://, // (protocol-relative), and
CRLF/whitespace injection.
- verify_id_token now caches discovery + JWKS (5-min TTL) using the
same pattern as oauth_routes._get_cached_discovery. New caching
regression test pins to one fetch per URL across multiple calls.
- /oauth/logout is now POST-only at the route layer (defeats passive
CSRF via <img src>). oauth_logout also validates Origin/Referer
against the configured mcp_server_url. Logout UI in user_info.html
converted from <a href> to <form method="post">.
- New storage.cleanup_expired_browser_sessions() called from the hourly
cleanup loop in app.py — previously these rows accumulated for users
who never explicitly logged out.
Nits:
- Demoted INFO logs that leaked oauth_config.keys() / client_id /
token-storage state to DEBUG. Operator-relevant outcome lines
(login successful, refresh token stored, logged out) stay INFO.
- verify_id_token algorithms widened to RS256, PS256, ES256 — covers
Azure AD (PS256) and Cognito/some Keycloak realms (ES256). Symmetric
and "none" remain off the allowlist.
- Migrated all Optional[X] usages in auth/storage.py to X | None per
CLAUDE.md.
Breaking change: GET /oauth/logout now returns 405. The in-tree logout
UI was migrated to a POST form; any external bookmark or curl-based
caller that relied on GET will need to switch.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
