Chris CoutinhoandClaude Opus 4.7
2d340a5a6b
Six findings from the latest claude-bot review on PR #758: - JWKS cache had no kid-miss refresh path (Medium): on IdP key rotation every login failed for up to _OIDC_CACHE_TTL. Evict and refetch once before raising, per OIDC core §10.1.1. - _should_use_secure_cookies fell back to nextcloud_host scheme, but the cookie is issued by the MCP server. Switch to settings.nextcloud_mcp_server_url so split-scheme deployments get the right Secure flag. - _origin_matches_self compared raw netloc strings, which include the port. Browsers omit default ports per RFC 6454 §6.2; an mcp_server_url like :443 falsely 403'd every legitimate logout. Normalise (scheme, host, port) tuples with default ports stripped. - delete_oauth_session exists in storage.py — drop the stale "we don't have this method" comment and call it eagerly so replays can't be processed and the table doesn't accumulate completed-but-not-yet-expired browser-login rows. - extract_user_id_from_token's unused ctx param renamed to _ctx to signal "intentionally unused" at the signature level. - provisioning_decorator instantiated RefreshTokenStorage per call. Switch to get_shared_storage() for the lock-protected process-wide singleton. Plus pre-push self-review catch: lazy-logging on the unchanged except arm in session_backend.py. Adds 5 regression tests: - JWKS rotation: success on refetch - JWKS rotation: still-missing-kid surfaces original error - JWKS rotation: network error during refresh wrapped as IdTokenVerificationError - default-port CSRF: explicit :443 in config + portless Origin - default-port CSRF: portless config + explicit :443 in Origin - scheme-mismatch CSRF: same host, different scheme rejected Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
99 lines
3.4 KiB
Python
99 lines
3.4 KiB
Python
"""Session-based authentication backend for Starlette routes.
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Provides browser-based authentication for admin UI routes, separate from
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MCP's OAuth authentication flow.
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"""
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import logging
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import os
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from starlette.authentication import (
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AuthCredentials,
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AuthenticationBackend,
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SimpleUser,
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)
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from starlette.requests import HTTPConnection
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logger = logging.getLogger(__name__)
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class SessionAuthBackend(AuthenticationBackend):
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"""Authentication backend using signed session cookies.
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For BasicAuth mode: Always authenticates as the configured user.
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For OAuth mode: Checks for valid session cookie with stored refresh token.
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"""
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def __init__(self, oauth_enabled: bool = False):
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"""Initialize session authentication backend.
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Args:
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oauth_enabled: Whether OAuth mode is enabled
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"""
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self.oauth_enabled = oauth_enabled
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async def authenticate(
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self, conn: HTTPConnection
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) -> tuple[AuthCredentials, SimpleUser] | None:
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"""Authenticate the request based on session cookie or BasicAuth mode.
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This backend is only applied to browser routes (/user/*) via a separate
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Starlette app mount. FastMCP routes use their own OAuth Bearer token
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authentication.
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Args:
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conn: HTTP connection
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Returns:
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Tuple of (credentials, user) if authenticated, None otherwise
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"""
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# BasicAuth mode: Always authenticated as the configured user
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if not self.oauth_enabled:
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username = os.getenv("NEXTCLOUD_USERNAME", "admin")
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return AuthCredentials(["authenticated", "admin"]), SimpleUser(username)
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# OAuth mode: opaque random session_id cookie -> user_id mapping.
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# Replaces the prior `mcp_session=<user_id>` cookie pattern (issue
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# #626 finding 2). The cookie value is no longer the user identity;
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# we look it up server-side and reject unknown / expired sessions.
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session_id = conn.cookies.get("mcp_session")
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if not session_id:
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logger.info("No session cookie found - redirecting to login")
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return None
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oauth_context = getattr(conn.app.state, "oauth_context", None)
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if not oauth_context:
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logger.warning("OAuth context not available in app state")
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return None
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storage = oauth_context.get("storage")
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if not storage:
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logger.warning("OAuth storage not available")
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return None
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try:
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user_id = await storage.get_browser_session_user(session_id)
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if not user_id:
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logger.info(
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"Browser session not found or expired (sid=%s…)", session_id[:8]
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)
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return None
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# Defense-in-depth: only authenticate sessions for users that
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# actually have a refresh token persisted. Logout deletes both,
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# so an expired/revoked user state will fail closed here.
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token_data = await storage.get_refresh_token(user_id)
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if not token_data:
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logger.warning(
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"Session %s… has no refresh token for user %s; rejecting",
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session_id[:8],
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user_id,
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)
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return None
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return AuthCredentials(["authenticated"]), SimpleUser(user_id)
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except Exception as e:
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logger.warning("Session validation error: %s", e)
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return None
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