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* feat(mcp): add delegate_auth_to_upstream flag for PKCE passthrough Adds an opt-in per-server flag that lets clients (e.g. VS Code) complete PKCE directly with an upstream OAuth2 MCP server, instead of LiteLLM double-gating with its own API-key/SSO check. Only honored when auth_type=oauth2 and the operator explicitly sets the flag; mixed-target or non-oauth2 requests fail closed. - Adds the field to Pydantic models, Prisma schema, and a migration - New MCPRequestHandler._target_servers_delegate_auth_to_upstream gate that runs only when no x-litellm-api-key is present, so authenticated users still get user_id resolution + stored-credential lookup - Anonymous callers now see delegate servers in get_allowed_mcp_servers (scoped to delegate servers only; the upstream still enforces auth) - mcp_management_endpoints: allow anonymous /authorize and /token for delegate servers so VS Code can complete PKCE without a LiteLLM session - UI toggle (shown only for oauth2) + payload/view wiring - Tests covering: oauth2 on/off, non-oauth2 with flag, mixed targets, no resolvable target, explicit key precedence, and 401 emission Co-authored-by: Cursor <cursoragent@cursor.com> * Enforce oauth2 for delegated MCP auth bypass Co-authored-by: Yassin Kortam <yassin@berri.ai> * fix(mcp): close secondary Authorization bypass for delegate servers The delegate-auth bypass gated only on the primary `x-litellm-api-key` header, so a LiteLLM key sent via `Authorization: Bearer sk-...` (the secondary header) was silently dropped — skipping spend tracking and rate limiting. Gate on the resolved litellm_api_key (which considers both headers) so the bypass fires only when neither is present. Also update the existing "Authorization header present" test to reflect that an upstream OAuth token now flows through the existing oauth2 fallback (LiteLLM auth attempt → fail → anonymous), not via the delegate branch. Co-authored-by: Cursor <cursoragent@cursor.com> * Avoid duplicate MCP OAuth credential lookup Co-authored-by: Yassin Kortam <yassin@berri.ai> * fix(mcp): block delegate bypass for M2M and internal-only servers Two security issues flagged in code review: 1. High – client_credentials (M2M) servers must not be delegatable: LiteLLM auto-fetches the upstream token using stored credentials, so allowing anonymous bypass would let any external caller invoke tools authenticated as LiteLLM's service account. Fix: check `server.has_client_credentials` in `_target_servers_delegate_auth_to_upstream`, the anonymous allow-list in `get_allowed_mcp_servers`, and `_mcp_oauth_user_api_key_auth`. 2. Medium – internal-only servers exposed to public internet: The anonymous delegate allow-list was not filtering by `available_on_public_internet`, so external callers with an upstream OAuth token could invoke tools on servers marked internal-only. Fix: add `available_on_public_internet` guard to the anonymous delegate server list in `get_allowed_mcp_servers`. Tests added for both cases. Co-authored-by: Cursor <cursoragent@cursor.com> * Require public MCP delegate auth servers Co-authored-by: Yassin Kortam <yassin@berri.ai> * fix(mcp): align delegate auth path parsing with downstream routing `_extract_target_server_names_from_path` used a naive segments-based split while `server.py::_get_mcp_servers_in_path` uses a regex that allows server names with one embedded slash and comma-separated lists. With the old parser, a request to `/mcp/<delegated>/<garbage>` was parsed as targeting `<delegated>` by the auth gate (bypassing LiteLLM auth) while the routing layer parsed it as `<delegated>/<garbage>` — when that name did not resolve, the request fell back to the anonymous allow-list, which can include `allow_all_keys` servers that normally require a LiteLLM key. Replace the parser with the same regex logic as `_get_mcp_servers_in_path` so auth gating sees the exact target name(s) downstream routing sees. Add regression tests covering parser parity and the specific extra-path-segment bypass attempt. https://claude.ai/code/session_01SjyPmwfmrq8fveFgw9iHW9 * fix(mcp): close header/path TOCTOU in MCP delegate auth gate `_target_servers_delegate_auth_to_upstream` and `_target_servers_use_oauth2` trusted the `x-mcp-servers` header when present, but `server.py::extract_mcp_auth_context` overrides that header with the path-derived list for `/mcp/...` routes. An attacker could set `x-mcp-servers: <delegated>` while pointing the URL path at a non-delegate server, flipping the auth gate without changing the target downstream routing actually uses. Extract a shared `_resolve_target_server_names` helper that mirrors the downstream override (path-derived names for `/mcp/...` routes, header value otherwise). Add regression tests covering the TOCTOU attempt and the helper's path-vs-header precedence. https://claude.ai/code/session_01SjyPmwfmrq8fveFgw9iHW9 * Fix delegated MCP OAuth test mock Co-authored-by: Yassin Kortam <yassin@berri.ai> * fix(mcp): drop unreachable /{server}/mcp branch in auth path parser `_extract_target_server_names_from_path` also matched the ``/{server_name}/mcp`` form, but the downstream parser ``_get_mcp_servers_in_path`` only handles ``/mcp/...`` — and ``dynamic_mcp_route`` in ``proxy_server`` rewrites ``/{name}/mcp`` to ``/mcp/{name}`` on the scope before the MCP handler runs. Parsing the un-rewritten form on the auth side was therefore unreachable in production, and contradicted the docstring's claim of mirroring the downstream parser — exactly the kind of mismatch that risks a future header/path TOCTOU if any new entry point skips the rewrite. Drop the branch; the canonical ``/mcp/...`` path matches both parsers. Update the regression test to assert the new behavior. https://claude.ai/code/session_01SjyPmwfmrq8fveFgw9iHW9 * Fix MCP path auth target resolution Co-authored-by: Yassin Kortam <yassin@berri.ai> * fix(mcp): require auth for refresh_token grants on delegate-auth servers `_mcp_oauth_user_api_key_auth` gates the unauthenticated PKCE flow for ``delegate_auth_to_upstream`` servers, but the bypass applied to BOTH ``/authorize`` and ``/token`` regardless of grant type. ``mcp_token`` accepts ``grant_type=refresh_token`` as well as ``authorization_code``, and ``exchange_token_with_server`` attaches the server's stored ``client_secret`` to whatever is forwarded upstream. An unauthenticated caller holding a refresh token issued to that OAuth client could mint fresh upstream access tokens through LiteLLM. Limit the anonymous bypass on ``/token`` to ``grant_type=authorization_code`` (the only grant PKCE actually protects via ``code_verifier``); fall through to normal LiteLLM auth for ``refresh_token`` and any other grant. ``/authorize`` continues to allow anonymous PKCE redirects. https://claude.ai/code/session_01SjyPmwfmrq8fveFgw9iHW9 * fix(ui): clear delegate_auth_to_upstream when switching off oauth2 The ``delegate_auth_to_upstream`` form field is rendered inside an ``isOAuth2 && (...)`` conditional, so the Form.Item unmounts when the user changes ``auth_type`` away from ``oauth2``. The follow-up ``form.setFieldValue("delegate_auth_to_upstream", false)`` runs after the field has already deregistered, so ``onFinish`` receives ``undefined`` and the fallback ``?? mcpServer.delegate_auth_to_upstream`` preserved the old ``true``. The flag then persisted in the database for a non-oauth2 server and silently re-activated if ``auth_type`` was later switched back to ``oauth2``. In the edit payload, force the flag to ``false`` whenever ``auth_type !== oauth2``; only trust the form value (and the existing DB fallback) when the server is actually oauth2. Backend defense-in-depth already ignores the flag for non-oauth2 servers, but the DB state should stay clean too. https://claude.ai/code/session_01SjyPmwfmrq8fveFgw9iHW9 * Fix MCP delegate auth reset on edit Co-authored-by: Yassin Kortam <yassin@berri.ai> --------- Co-authored-by: Cursor <cursoragent@cursor.com> Co-authored-by: Yassin Kortam <yassin@berri.ai> Co-authored-by: Claude <claude@anthropic.com> |
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|---|---|---|
| .. | ||
| _experimental/mcp_server | ||
| agent_endpoints | ||
| anthropic_endpoints | ||
| auth | ||
| client | ||
| common_utils | ||
| db | ||
| discovery_endpoints | ||
| experimental/mcp_server | ||
| google_endpoints | ||
| guardrails | ||
| health_endpoints | ||
| hooks | ||
| image_endpoints | ||
| management_endpoints | ||
| management_helpers | ||
| memory | ||
| middleware | ||
| openai_files_endpoint | ||
| pass_through_endpoints | ||
| policy_engine | ||
| prompts | ||
| public_endpoints | ||
| rag_endpoints | ||
| realtime_endpoints | ||
| response_api_endpoints | ||
| spend_tracking | ||
| test_configs | ||
| ui_crud_endpoints | ||
| vector_store_endpoints | ||
| __init__.py | ||
| conftest.py | ||
| test_aiohttp_cleanup_closed.py | ||
| test_aiohttp_session_recovery.py | ||
| test_api_key_masking_in_errors.py | ||
| test_audio_speech_prometheus_hooks.py | ||
| test_batch_expiry.py | ||
| test_batch_metadata_none_fix.py | ||
| test_batch_retrieve_bedrock.py | ||
| test_budget_reservation.py | ||
| test_caching_routes.py | ||
| test_chat_completion_metadata.py | ||
| test_common_request_processing.py | ||
| test_cors_config.py | ||
| test_custom_proxy.py | ||
| test_empty_model_list.py | ||
| test_enforce_user_param.py | ||
| test_fallback_management_endpoints.py | ||
| test_fastapi_offline_routes.py | ||
| test_filter_models_by_team_access_group.py | ||
| test_health_check_functions.py | ||
| test_health_check_max_tokens.py | ||
| test_langfuse_passthrough_security.py | ||
| test_lazy_openapi_snapshot.py | ||
| test_litellm_pre_call_utils.py | ||
| test_max_budget_env_var.py | ||
| test_mcp_asgi_response.py | ||
| test_model_dump_with_preserved_fields.py | ||
| test_model_id_header_propagation.py | ||
| test_model_info_default_limits.py | ||
| test_model_level_guardrails.py | ||
| test_openapi_schema_validation.py | ||
| test_pricing_field_strip.py | ||
| test_prometheus_cleanup.py | ||
| test_provider_url_destination_guard.py | ||
| test_proxy_cli.py | ||
| test_proxy_server.py | ||
| test_proxy_types.py | ||
| test_proxy_utils.py | ||
| test_pyroscope.py | ||
| test_redis_auth_cache_flag.py | ||
| test_response_model_sanitization.py | ||
| test_route_a2a_models.py | ||
| test_route_llm_request.py | ||
| test_sensitive_route_auth.py | ||
| test_shared_health_check.py | ||
| test_spend_log_cleanup.py | ||
| test_swagger_chat_completions.py | ||
| test_team_member_update.py | ||
| test_team_org_move.py | ||
| test_tools_allowlist_enforcement.py | ||
| test_update_llm_router_resilience.py | ||
| test_utils.py | ||