diff --git a/litellm/proxy/_experimental/mcp_server/discoverable_endpoints.py b/litellm/proxy/_experimental/mcp_server/discoverable_endpoints.py index 6ede1c553e8..928373d93d8 100644 --- a/litellm/proxy/_experimental/mcp_server/discoverable_endpoints.py +++ b/litellm/proxy/_experimental/mcp_server/discoverable_endpoints.py @@ -3,7 +3,7 @@ import html as _html import json import secrets import time -from collections.abc import Mapping +from collections.abc import Callable, Mapping from datetime import datetime, timezone from typing import TYPE_CHECKING, Any, Final, Literal, Optional from urllib.parse import parse_qsl, urlencode, urlparse, urlunparse @@ -663,15 +663,18 @@ def _endpoint_not_configured_detail( ) -async def _server_with_oauth_endpoints(mcp_server: MCPServer) -> MCPServer: - """Join deferred OAuth discovery only when this server still has no authorize URL. +async def _server_with_oauth_endpoints( + mcp_server: MCPServer, + needed_endpoint: Callable[[MCPServer], str | None], +) -> MCPServer: + """Join deferred OAuth discovery only when the endpoint this caller needs is still missing. Admin-entered endpoints live on ``configured_*`` after an anchored issuer empties the - resolved fields. Those already let authorize/token run, so discovery is not awaited - and cannot 503 over a leftover pin. A server with nothing configured still joins the - deferred task; no slot is a no-op and the caller 400s. + resolved fields. A caller whose needed endpoint already resolves never awaits discovery + and cannot 503 over a leftover pin. A server still missing it joins the deferred task; + no slot is a no-op and the caller 400s. """ - if mcp_server.effective_authorization_url is not None: + if needed_endpoint(mcp_server) is not None: return mcp_server from litellm.proxy._experimental.mcp_server.mcp_server_manager import ( # noqa: PLC0415 # circular import with mcp_server_manager at module load global_mcp_server_manager, @@ -829,7 +832,7 @@ async def authorize_with_server( ephemeral_dcr_client: "EphemeralDcrClient | None" = None, ): _raise_if_not_oauth2(mcp_server) - resolved_server: Final = await _server_with_oauth_endpoints(mcp_server) + resolved_server: Final = await _server_with_oauth_endpoints(mcp_server, lambda s: s.effective_authorization_url) if resolved_server.effective_authorization_url is None: raise HTTPException( status_code=400, @@ -841,7 +844,7 @@ async def authorize_with_server( ), ) - if mcp_server.is_dcr_bridge: + if resolved_server.is_dcr_bridge: # Enforce S256 PKCE on both bridge arms. The relay arm forwards the validated, # now-non-optional pair to the upstream authorize; the short-circuit arm keeps # calling this for its enforcement side effect, then falls through to the gateway @@ -850,9 +853,9 @@ async def authorize_with_server( # A gateway-minted ephemeral client is registered against {base}/callback, so its # flow must run the short-circuit arm; the relay arm is only for clients that # registered themselves through the front door and hold their own redirect binding. - if _dcr_bridge_relays_client_registration(mcp_server) and ephemeral_dcr_client is None: + if _dcr_bridge_relays_client_registration(resolved_server) and ephemeral_dcr_client is None: return _redirect_to_upstream_authorize( - mcp_server=mcp_server, + mcp_server=resolved_server, client_id=client_id, redirect_uri=redirect_uri, state=state, @@ -878,7 +881,7 @@ async def authorize_with_server( # litellm key, so the browser session is the only identity source; without one there is nothing to # bind, so send the user through login first. Every other oauth2 server keeps the identity-less state. litellm_user_id: str | None = None - if mcp_server.is_dcr_bridge and mcp_server.is_oauth_delegate: + if resolved_server.is_dcr_bridge and resolved_server.is_oauth_delegate: from litellm.proxy._experimental.mcp_server.byok_oauth_endpoints import ( # noqa: PLC0415 # inline import avoids a module-load circular import _user_id_from_session_cookie, ) @@ -888,7 +891,7 @@ async def authorize_with_server( return _redirect_to_litellm_login(request) denial: Final = await _bridge_authorize_access_denial( litellm_user_id=litellm_user_id, - mcp_server=mcp_server, + mcp_server=resolved_server, redirect_uri=redirect_uri, state=state, ) @@ -902,7 +905,7 @@ async def authorize_with_server( code_challenge_method=code_challenge_method, client_redirect_uri=redirect_uri, litellm_user_id=litellm_user_id, - mcp_server_id=mcp_server.server_id if (litellm_user_id or ephemeral_dcr_client) else None, + mcp_server_id=resolved_server.server_id if (litellm_user_id or ephemeral_dcr_client) else None, dcr_client_id=ephemeral_dcr_client.client_id if ephemeral_dcr_client else None, dcr_client_secret=ephemeral_dcr_client.client_secret if ephemeral_dcr_client else None, dcr_token_endpoint_auth_method=ephemeral_dcr_client.token_endpoint_auth_method @@ -912,22 +915,22 @@ async def authorize_with_server( relay_state: Final = secrets.token_urlsafe(_OAUTH_STATE_HANDLE_BYTES) params: Final = { - "client_id": mcp_server.client_id if mcp_server.client_id else client_id, + "client_id": resolved_server.client_id if resolved_server.client_id else client_id, "redirect_uri": f"{request_base_url}/callback", "state": relay_state, "response_type": response_type or "code", } if scope: params["scope"] = scope - elif mcp_server.scopes: - params["scope"] = " ".join(mcp_server.scopes) + elif resolved_server.scopes: + params["scope"] = " ".join(resolved_server.scopes) if code_challenge: params["code_challenge"] = code_challenge if code_challenge_method: params["code_challenge_method"] = code_challenge_method - upstream_resource: Final = resolve_upstream_resource(mcp_server) + upstream_resource: Final = resolve_upstream_resource(resolved_server) if upstream_resource: params["resource"] = upstream_resource @@ -964,7 +967,7 @@ async def exchange_token_with_server( if grant_type not in ("authorization_code", "refresh_token"): raise HTTPException(status_code=400, detail="Unsupported grant_type") - resolved_server: Final = await _server_with_oauth_endpoints(mcp_server) + resolved_server: Final = await _server_with_oauth_endpoints(mcp_server, lambda s: s.effective_token_url) token_url: Final = resolved_server.effective_token_url if token_url is None: raise HTTPException( @@ -985,16 +988,16 @@ async def exchange_token_with_server( # recovered from a sealed code) must authenticate the way its own registration was granted, # not the way the server row is configured; callers that carry no method keep the row's method # as before. - resolved_client_id: Final = mcp_server.client_id if mcp_server.client_id else client_id - resolved_client_secret: Final = mcp_server.client_secret if mcp_server.client_id else client_secret + resolved_client_id: Final = resolved_server.client_id if resolved_server.client_id else client_id + resolved_client_secret: Final = resolved_server.client_secret if resolved_server.client_id else client_secret resolved_auth_method: Final = ( - mcp_server.token_endpoint_auth_method - if mcp_server.client_id - else (client_token_endpoint_auth_method or mcp_server.token_endpoint_auth_method) + resolved_server.token_endpoint_auth_method + if resolved_server.client_id + else (client_token_endpoint_auth_method or resolved_server.token_endpoint_auth_method) ) try: token_request: Final = build_upstream_oauth2_token_request( - mcp_server, + resolved_server, auth_method=resolved_auth_method, client_id=resolved_client_id, client_secret=resolved_client_secret, @@ -1007,14 +1010,14 @@ async def exchange_token_with_server( bridge_upstream_refresh: SecretStr | None = None bridge_upstream_scope: str | None = None refresh_request_scope: str | None = None - is_bridge: Final = mcp_server.is_oauth_delegate and mcp_server.is_dcr_bridge + is_bridge: Final = resolved_server.is_oauth_delegate and resolved_server.is_dcr_bridge if grant_type == "refresh_token": # Phase 1 for a bridge refresh: open the client's refresh envelope, re-validate the sealed # identity, and unwrap the real upstream refresh token BEFORE building token_data, so the exchange # sends the upstream token and never the envelope. A failure returns without touching the upstream. if is_bridge: - prepared_refresh: Final = await _prepare_bridge_refresh(mcp_server, refresh_token) + prepared_refresh: Final = await _prepare_bridge_refresh(resolved_server, refresh_token) if not isinstance(prepared_refresh, _BridgeRefreshReady): return _bridge_mint_error_response(prepared_refresh) bridge_mint_ready = prepared_refresh.ready @@ -1051,13 +1054,13 @@ async def exchange_token_with_server( # A raw upstream code (scripted path) opens to None and the code is used as-is. bridge_identity = open_bridge_authorization_code(code) if bridge_identity is not None: - if bridge_identity.mcp_server_id != mcp_server.server_id: + if bridge_identity.mcp_server_id != resolved_server.server_id: raise HTTPException( status_code=400, detail="Authorization code was issued for a different MCP server", ) code = bridge_identity.upstream_code - bridge_token_relay: Final = _dcr_bridge_relays_client_registration(mcp_server) + bridge_token_relay: Final = _dcr_bridge_relays_client_registration(resolved_server) if bridge_token_relay and not redirect_uri: raise HTTPException( status_code=400, @@ -1079,7 +1082,7 @@ async def exchange_token_with_server( # Phase 1 for a bridge authorization_code mint: resolve identity (the SSO user recovered above, or # the presented litellm key) and the envelope keys BEFORE the exchange consumes the single-use code. if is_bridge: - prepared: Final = await _prepare_bridge_mint(request, mcp_server, bridge_identity) + prepared: Final = await _prepare_bridge_mint(request, resolved_server, bridge_identity) if not isinstance(prepared, _BridgeMintReady): return _bridge_mint_error_response(prepared) bridge_mint_ready = prepared @@ -1096,8 +1099,8 @@ async def exchange_token_with_server( except httpx.HTTPStatusError as exc: fault: Final = classify_upstream_token_rejection( exc.response, - credential_source=_token_credential_source(mcp_server), - log_context=mcp_server.server_id, + credential_source=_token_credential_source(resolved_server), + log_context=resolved_server.server_id, ) upstream_rejected_bridge_refresh: Final = ( is_bridge @@ -1110,7 +1113,7 @@ async def exchange_token_with_server( "bridge refresh: the upstream rejected the sealed refresh token for server=%s with " "invalid_grant (revoked or expired at the IdP); returning invalid_grant so the client " "re-runs authorization_code rather than an opaque upstream error", - mcp_server.server_id, + resolved_server.server_id, ) return _bridge_mint_error_response("invalid_refresh") return render_token_fault(fault) @@ -1123,22 +1126,22 @@ async def exchange_token_with_server( # Validate token response against server-configured rules before any storage. # This rejects tokens from wrong Slack workspaces, Atlassian orgs, etc. - if mcp_server.token_validation and isinstance(mcp_server.token_validation, dict): + if resolved_server.token_validation and isinstance(resolved_server.token_validation, dict): _validate_token_response( token_response=token_response, - validation_rules=mcp_server.token_validation, - server_id=mcp_server.server_id, + validation_rules=resolved_server.token_validation, + server_id=resolved_server.server_id, ) # Store server-side when the server is configured for per-user OAuth and # the calling client has provided a valid LiteLLM identity. # Errors are non-fatal: the token is still returned to the client. - if mcp_server.needs_user_oauth_token: + if resolved_server.needs_user_oauth_token: user_id: Final = await _extract_user_id_from_request(request) if user_id: try: await _store_per_user_token_server_side( - server=mcp_server, + server=resolved_server, user_id=user_id, token_response=token_response, ) @@ -1146,7 +1149,7 @@ async def exchange_token_with_server( verbose_logger.warning( "exchange_token_with_server: server-side storage failed for user=%s server=%s: %s", user_id, - mcp_server.server_id, + resolved_server.server_id, exc, ) else: @@ -1156,7 +1159,7 @@ async def exchange_token_with_server( "requires the stored token, so the client will be challenged with 401 on reconnect. " "Ensure the request carries a valid LiteLLM key (x-litellm-api-key or Authorization), " "or store it via POST /mcp/server/{id}/oauth-user-credential.", - mcp_server.server_id, + resolved_server.server_id, ) # A DCR-bridge oauth_delegate server hands the client a gateway-bound envelope (identity plus the @@ -1167,7 +1170,9 @@ async def exchange_token_with_server( token_response = {**token_response, "scope": refresh_request_scope} # Phase 3: seal the upstream grant into the client-held envelope; failures map through the same # OAuth-shaped response as the phase-1 preconditions. - minted: Final = _finish_bridge_mint(bridge_mint_ready, mcp_server, token_response, datetime.now(timezone.utc)) + minted: Final = _finish_bridge_mint( + bridge_mint_ready, resolved_server, token_response, datetime.now(timezone.utc) + ) return minted if isinstance(minted, JSONResponse) else _bridge_mint_error_response(minted) raw_access_token: Final = token_response.get("access_token") if isinstance(token_response, dict) else None @@ -1682,7 +1687,7 @@ async def register_client_with_server( ): return dummy_return - resolved_server: Final = await _server_with_oauth_endpoints(mcp_server) + resolved_server: Final = await _server_with_oauth_endpoints(mcp_server, lambda s: s.effective_authorization_url) if resolved_server.effective_authorization_url is None: raise HTTPException( status_code=400, @@ -1715,13 +1720,15 @@ async def register_client_with_server( response: Final = await _post_dcr_registration( registration_url=registration_url, register_data=register_data, - server_id=mcp_server.server_id, + server_id=resolved_server.server_id, ) token_response = response.json() if persist_credentials and not bridge_relay: - persistence_result = await _persist_dcr_client_registration(mcp_server, token_response, current_redirect_uri) + persistence_result = await _persist_dcr_client_registration( + resolved_server, token_response, current_redirect_uri + ) if persistence_result == "reused": return dummy_return diff --git a/tests/test_litellm/proxy/_experimental/mcp_server/test_discoverable_endpoints.py b/tests/test_litellm/proxy/_experimental/mcp_server/test_discoverable_endpoints.py index 790b5c7ad22..46c9c21e80d 100644 --- a/tests/test_litellm/proxy/_experimental/mcp_server/test_discoverable_endpoints.py +++ b/tests/test_litellm/proxy/_experimental/mcp_server/test_discoverable_endpoints.py @@ -8855,7 +8855,7 @@ async def test_authorize_wall_names_the_issuer_for_anchored_servers(): @pytest.mark.asyncio -async def test_authorize_uses_admin_entered_github_oauth_urls_after_issuer_yield(): +async def test_authorize_uses_admin_entered_github_oauth_urls_after_issuer_yield(monkeypatch): """GitHub MCP servers store Authorization URL and Token URL on the row. 1.99 can empty the resolved authorization_url when a leftover issuer is treated as a pin (RFC 8414 yield). The UI authorize must still redirect to the admin-entered GitHub authorize URL @@ -8887,15 +8887,14 @@ async def test_authorize_uses_admin_entered_github_oauth_urls_after_issuer_yield mock_request.base_url = "https://litellm.example.com/" mock_request.headers = {} - with patch("litellm.proxy._experimental.mcp_server.discoverable_endpoints.encrypt_value_helper") as mock_encrypt: - mock_encrypt.return_value = "mocked_encrypted_state" - response = await authorize_with_server( - request=mock_request, - mcp_server=server, - client_id="github-app-client", - redirect_uri="http://127.0.0.1:60108/callback", - state="state123", - ) + monkeypatch.setenv("LITELLM_SALT_KEY", "sk-test-salt-for-lit-6255") + response = await authorize_with_server( + request=mock_request, + mcp_server=server, + client_id="github-app-client", + redirect_uri="http://127.0.0.1:60108/callback", + state="state123", + ) assert response.status_code == 307 assert "https://github.com/login/oauth/authorize" in response.headers["location"] @@ -8926,6 +8925,137 @@ def test_oauth_endpoints_count_admin_entered_urls_as_resolved(): assert _oauth_endpoints_unresolved(server) is False +@pytest.mark.asyncio +async def test_token_exchange_with_configured_token_url_never_joins_discovery(monkeypatch): + """A server can hold an admin-entered Token URL while its Authorization URL is absent. The + token exchange must post to that stored endpoint without awaiting deferred discovery, which + can 503 against an unreachable issuer even though nothing it resolves is needed here.""" + from litellm.proxy._experimental.mcp_server import ( + discoverable_endpoints, + mcp_server_manager, + ) + from litellm.proxy._experimental.mcp_server.discoverable_endpoints import ( + exchange_token_with_server, + ) + from litellm.types.mcp import MCPAuth, MCPTransport + from litellm.types.mcp_server.mcp_server_manager import MCPServer + + server = MCPServer( + server_id="token-url-only", + name="token_url_only", + server_name="token_url_only", + alias="token_url_only", + url="https://mcp.example.com/mcp/", + transport=MCPTransport.http, + auth_type=MCPAuth.oauth2, + client_id="cid", + client_secret="cs", + authorization_url=None, + token_url=None, + issuer="https://idp.example.com", + issuer_is_anchored=True, + configured_token_url="https://idp.example.com/oauth/token", + ) + + async def fail_discovery(_srv): + raise AssertionError("the exchange joined deferred discovery despite a stored token url") + + monkeypatch.setattr( + mcp_server_manager.global_mcp_server_manager, + "ensure_oauth_metadata_discovered", + fail_discovery, + ) + fake_http_response = MagicMock() + fake_http_response.json.return_value = {"access_token": "tok", "token_type": "Bearer"} + fake_http_response.raise_for_status = MagicMock() + fake_http_client = MagicMock() + fake_http_client.post = AsyncMock(return_value=fake_http_response) + monkeypatch.setattr( + discoverable_endpoints, + "get_async_httpx_client", + lambda llm_provider: fake_http_client, + ) + mock_request = MagicMock() + mock_request.base_url = "https://litellm.example.com/" + mock_request.headers = {} + + response = await exchange_token_with_server( + request=mock_request, + mcp_server=server, + grant_type="authorization_code", + code="upstream-code", + redirect_uri="http://127.0.0.1:3000/cb", + client_id="cid", + client_secret=None, + code_verifier=None, + ) + + assert response.status_code == 200 + assert fake_http_client.post.await_args.args[0] == "https://idp.example.com/oauth/token" + + +@pytest.mark.asyncio +async def test_bridge_authorize_relays_with_registration_url_resolved_by_deferred_discovery(monkeypatch): + """When deferred discovery resolves a DCR-bridge server during the authorize request, the + relay-vs-short-circuit call must read the resolved server: a client that registered itself + through the front door keeps its own redirect binding instead of being routed through the + gateway callback the upstream never granted it.""" + from litellm.proxy._experimental.mcp_server import mcp_server_manager + from litellm.proxy._experimental.mcp_server.discoverable_endpoints import ( + authorize_with_server, + ) + from litellm.types.mcp import MCPAuth, MCPTransport + from litellm.types.mcp_server.mcp_server_manager import MCPServer + + server = MCPServer( + server_id="bridge-deferred", + name="bridge_deferred", + server_name="bridge_deferred", + alias="bridge_deferred", + url="https://mcp.example.com/mcp/", + transport=MCPTransport.http, + auth_type=MCPAuth.true_passthrough, + dcr_bridge=True, + authorization_url=None, + token_url=None, + registration_url=None, + ) + resolved = server.model_copy( + update={ + "authorization_url": "https://idp.example.com/oauth/authorize", + "token_url": "https://idp.example.com/oauth/token", + "registration_url": "https://idp.example.com/oauth/register", + } + ) + + async def resolve_discovery(_srv): + return resolved + + monkeypatch.setattr( + mcp_server_manager.global_mcp_server_manager, + "ensure_oauth_metadata_discovered", + resolve_discovery, + ) + mock_request = MagicMock() + mock_request.base_url = "https://litellm.example.com/" + mock_request.headers = {} + + response = await authorize_with_server( + request=mock_request, + mcp_server=server, + client_id="front-door-client", + redirect_uri="http://127.0.0.1:60110/client-callback", + state="state456", + code_challenge="E9Melhoa2OwvFrEMTJguCHaoeK1t8URWbuGJSstw-cM", + code_challenge_method="S256", + ) + + assert response.status_code == 307 + location = response.headers["location"] + assert location.startswith("https://idp.example.com/oauth/authorize") + assert "redirect_uri=http%3A%2F%2F127.0.0.1%3A60110%2Fclient-callback" in location + + def test_passthrough_authorization_code_round_trips_and_rejects_hostile_input(): """The passthrough gateway code seals and recovers the ephemeral DCR client and upstream code, and is total over hostile input: a raw upstream code opens to None, and a tampered or