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fix: pass conformance auth scenarios, add RFC 8707 resource validation (#2010)

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This commit is contained in:
Felix Weinberger
2026-02-09 11:41:03 +00:00
committed by GitHub
parent 7c7c13b648
commit 239d682b6f
4 changed files with 187 additions and 8 deletions
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.github/actions/conformance/client.py
+22 -1
View File
@@ -275,6 +275,27 @@ async def run_client_credentials_basic(server_url: str) -> None:
async def run_auth_code_client(server_url: str) -> None:
"""Authorization code flow (default for auth/* scenarios)."""
callback_handler = ConformanceOAuthCallbackHandler()
storage = InMemoryTokenStorage()
# Check for pre-registered client credentials from context
context_json = os.environ.get("MCP_CONFORMANCE_CONTEXT")
if context_json:
try:
context = json.loads(context_json)
client_id = context.get("client_id")
client_secret = context.get("client_secret")
if client_id:
await storage.set_client_info(
OAuthClientInformationFull(
client_id=client_id,
client_secret=client_secret,
redirect_uris=[AnyUrl("http://localhost:3000/callback")],
token_endpoint_auth_method="client_secret_basic" if client_secret else "none",
)
)
logger.debug(f"Pre-loaded client credentials: client_id={client_id}")
except json.JSONDecodeError:
logger.exception("Failed to parse MCP_CONFORMANCE_CONTEXT")
oauth_auth = OAuthClientProvider(
server_url=server_url,
@@ -284,7 +305,7 @@ async def run_auth_code_client(server_url: str) -> None:
grant_types=["authorization_code", "refresh_token"],
response_types=["code"],
),
storage=InMemoryTokenStorage(),
storage=storage,
redirect_handler=callback_handler.handle_redirect,
callback_handler=callback_handler.handle_callback,
client_metadata_url="https://conformance-test.local/client-metadata.json",
.github/workflows/conformance.yml
+4 -5
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@@ -1,10 +1,9 @@
name: Conformance Tests
on:
# Disabled: conformance tests are currently broken in CI
# push:
# branches: [main]
# pull_request:
push:
branches: [main]
pull_request:
workflow_dispatch:
concurrency:
@@ -43,4 +42,4 @@ jobs:
with:
node-version: 24
- run: uv sync --frozen --all-extras --package mcp
- run: npx @modelcontextprotocol/conformance@0.1.10 client --command 'uv run --frozen python .github/actions/conformance/client.py' --suite all
- run: npx @modelcontextprotocol/conformance@0.1.13 client --command 'uv run --frozen python .github/actions/conformance/client.py' --suite all
src/mcp/client/auth/oauth2.py
+28
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@@ -229,6 +229,7 @@ class OAuthClientProvider(httpx.Auth):
callback_handler: Callable[[], Awaitable[tuple[str, str | None]]] | None = None,
timeout: float = 300.0,
client_metadata_url: str | None = None,
validate_resource_url: Callable[[str, str | None], Awaitable[None]] | None = None,
):
"""Initialize OAuth2 authentication.
@@ -243,6 +244,10 @@ class OAuthClientProvider(httpx.Auth):
advertises client_id_metadata_document_supported=true, this URL will be
used as the client_id instead of performing dynamic client registration.
Must be a valid HTTPS URL with a non-root pathname.
validate_resource_url: Optional callback to override resource URL validation.
Called with (server_url, prm_resource) where prm_resource is the resource
from Protected Resource Metadata (or None if not present). If not provided,
default validation rejects mismatched resources per RFC 8707.
Raises:
ValueError: If client_metadata_url is provided but not a valid HTTPS URL
@@ -263,6 +268,7 @@ class OAuthClientProvider(httpx.Auth):
timeout=timeout,
client_metadata_url=client_metadata_url,
)
self._validate_resource_url_callback = validate_resource_url
self._initialized = False
async def _handle_protected_resource_response(self, response: httpx.Response) -> bool:
@@ -476,6 +482,26 @@ class OAuthClientProvider(httpx.Auth):
metadata = OAuthMetadata.model_validate_json(content)
self.context.oauth_metadata = metadata
async def _validate_resource_match(self, prm: ProtectedResourceMetadata) -> None:
"""Validate that PRM resource matches the server URL per RFC 8707."""
prm_resource = str(prm.resource) if prm.resource else None
if self._validate_resource_url_callback is not None:
await self._validate_resource_url_callback(self.context.server_url, prm_resource)
return
if not prm_resource:
return # pragma: no cover
default_resource = resource_url_from_server_url(self.context.server_url)
# Normalize: Pydantic AnyHttpUrl adds trailing slash to root URLs
# (e.g. "https://example.com/") while resource_url_from_server_url may not.
if not default_resource.endswith("/"):
default_resource += "/"
if not prm_resource.endswith("/"):
prm_resource += "/"
if not check_resource_allowed(requested_resource=default_resource, configured_resource=prm_resource):
raise OAuthFlowError(f"Protected resource {prm_resource} does not match expected {default_resource}")
async def async_auth_flow(self, request: httpx.Request) -> AsyncGenerator[httpx.Request, httpx.Response]:
"""HTTPX auth flow integration."""
async with self.context.lock:
@@ -517,6 +543,8 @@ class OAuthClientProvider(httpx.Auth):
prm = await handle_protected_resource_response(discovery_response)
if prm:
# Validate PRM resource matches server URL (RFC 8707)
await self._validate_resource_match(prm)
self.context.protected_resource_metadata = prm
# todo: try all authorization_servers to find the OASM
tests/client/test_auth.py
+133 -2
View File
@@ -11,6 +11,7 @@ from inline_snapshot import Is, snapshot
from pydantic import AnyHttpUrl, AnyUrl
from mcp.client.auth import OAuthClientProvider, PKCEParameters
from mcp.client.auth.exceptions import OAuthFlowError
from mcp.client.auth.utils import (
build_oauth_authorization_server_metadata_discovery_urls,
build_protected_resource_metadata_discovery_urls,
@@ -818,6 +819,136 @@ class TestProtectedResourceMetadata:
assert "resource=" in content
@pytest.mark.anyio
async def test_validate_resource_rejects_mismatched_resource(
client_metadata: OAuthClientMetadata, mock_storage: MockTokenStorage
) -> None:
"""Client must reject PRM resource that doesn't match server URL."""
provider = OAuthClientProvider(
server_url="https://api.example.com/v1/mcp",
client_metadata=client_metadata,
storage=mock_storage,
)
provider._initialized = True
prm = ProtectedResourceMetadata(
resource=AnyHttpUrl("https://evil.example.com/mcp"),
authorization_servers=[AnyHttpUrl("https://auth.example.com")],
)
with pytest.raises(OAuthFlowError, match="does not match expected"):
await provider._validate_resource_match(prm)
@pytest.mark.anyio
async def test_validate_resource_accepts_matching_resource(
client_metadata: OAuthClientMetadata, mock_storage: MockTokenStorage
) -> None:
"""Client must accept PRM resource that matches server URL."""
provider = OAuthClientProvider(
server_url="https://api.example.com/v1/mcp",
client_metadata=client_metadata,
storage=mock_storage,
)
provider._initialized = True
prm = ProtectedResourceMetadata(
resource=AnyHttpUrl("https://api.example.com/v1/mcp"),
authorization_servers=[AnyHttpUrl("https://auth.example.com")],
)
# Should not raise
await provider._validate_resource_match(prm)
@pytest.mark.anyio
async def test_validate_resource_custom_callback(
client_metadata: OAuthClientMetadata, mock_storage: MockTokenStorage
) -> None:
"""Custom callback overrides default validation."""
callback_called_with: list[tuple[str, str | None]] = []
async def custom_validate(server_url: str, prm_resource: str | None) -> None:
callback_called_with.append((server_url, prm_resource))
provider = OAuthClientProvider(
server_url="https://api.example.com/v1/mcp",
client_metadata=client_metadata,
storage=mock_storage,
validate_resource_url=custom_validate,
)
provider._initialized = True
# This would normally fail default validation (different origin),
# but custom callback accepts it
prm = ProtectedResourceMetadata(
resource=AnyHttpUrl("https://evil.example.com/mcp"),
authorization_servers=[AnyHttpUrl("https://auth.example.com")],
)
await provider._validate_resource_match(prm)
assert callback_called_with == snapshot([("https://api.example.com/v1/mcp", "https://evil.example.com/mcp")])
@pytest.mark.anyio
async def test_validate_resource_accepts_root_url_with_trailing_slash(
client_metadata: OAuthClientMetadata, mock_storage: MockTokenStorage
) -> None:
"""Root URLs with trailing slash normalization should match."""
provider = OAuthClientProvider(
server_url="https://api.example.com",
client_metadata=client_metadata,
storage=mock_storage,
)
provider._initialized = True
prm = ProtectedResourceMetadata(
resource=AnyHttpUrl("https://api.example.com/"),
authorization_servers=[AnyHttpUrl("https://auth.example.com")],
)
# Should not raise despite trailing slash difference
await provider._validate_resource_match(prm)
@pytest.mark.anyio
async def test_validate_resource_accepts_server_url_with_trailing_slash(
client_metadata: OAuthClientMetadata, mock_storage: MockTokenStorage
) -> None:
"""Server URL with trailing slash should match PRM resource."""
provider = OAuthClientProvider(
server_url="https://api.example.com/v1/mcp/",
client_metadata=client_metadata,
storage=mock_storage,
)
provider._initialized = True
prm = ProtectedResourceMetadata(
resource=AnyHttpUrl("https://api.example.com/v1/mcp"),
authorization_servers=[AnyHttpUrl("https://auth.example.com")],
)
# Should not raise - both normalize to the same URL with trailing slash
await provider._validate_resource_match(prm)
@pytest.mark.anyio
async def test_get_resource_url_uses_canonical_when_prm_mismatches(
client_metadata: OAuthClientMetadata, mock_storage: MockTokenStorage
) -> None:
"""get_resource_url falls back to canonical URL when PRM resource doesn't match."""
provider = OAuthClientProvider(
server_url="https://api.example.com/v1/mcp",
client_metadata=client_metadata,
storage=mock_storage,
)
provider._initialized = True
# Set PRM with a resource that is NOT a parent of the server URL
provider.context.protected_resource_metadata = ProtectedResourceMetadata(
resource=AnyHttpUrl("https://other.example.com/mcp"),
authorization_servers=[AnyHttpUrl("https://auth.example.com")],
)
# get_resource_url should return the canonical server URL, not the PRM resource
assert provider.context.get_resource_url() == snapshot("https://api.example.com/v1/mcp")
class TestRegistrationResponse:
"""Test client registration response handling."""
@@ -963,7 +1094,7 @@ class TestAuthFlow:
# Send a successful discovery response with minimal protected resource metadata
discovery_response = httpx.Response(
200,
content=b'{"resource": "https://api.example.com/mcp", "authorization_servers": ["https://auth.example.com"]}',
content=b'{"resource": "https://api.example.com/v1/mcp", "authorization_servers": ["https://auth.example.com"]}',
request=discovery_request,
)
@@ -1116,7 +1247,7 @@ class TestAuthFlow:
# Send a successful discovery response with minimal protected resource metadata
discovery_response = httpx.Response(
200,
content=b'{"resource": "https://api.example.com/mcp", "authorization_servers": ["https://auth.example.com"]}',
content=b'{"resource": "https://api.example.com/v1/mcp", "authorization_servers": ["https://auth.example.com"]}',
request=discovery_request,
)