Harden portal: shared-secret auth for key injector + token-authenticated webhook URL

app/main.py

@@ -17,6 +17,7 @@ import os
 import json
 import logging
 import sqlite3
+import secrets
 
 import httpx
 from fastapi import FastAPI, Request, Response, HTTPException
@@ -34,6 +35,16 @@ LITELLM_BASE = os.environ.get("LITELLM_BASE", "https://gateway.inference.coop")
 LITELLM_MASTER_KEY = os.environ.get("LITELLM_MASTER_KEY", "")
 OPENCOLLECTIVE_SECRET = os.environ.get("OPENCOLLECTIVE_WEBHOOK_SECRET", "")
 
+# Shared secret that LibreChat sends as a header on every request, so the
+# portal can verify the request genuinely came through LibreChat (which is
+# behind Cloudron SSO) rather than a direct, spoofed request.
+PORTAL_SECRET = os.environ.get("PORTAL_SECRET", "")
+
+# Secret token required in the Open Collective webhook URL path. Open
+# Collective's generic webhooks are not HMAC-signed, so a secret in the URL
+# is the standard way to authenticate them.
+WEBHOOK_TOKEN = os.environ.get("WEBHOOK_TOKEN", "")
+
 # Monthly credit budget (in USD of tokens) for all members.
 # Single sliding-scale tier: everyone gets the same $15/month in credits,
 # regardless of their $10/15/20 contribution. Governance decision (Loomio).
@@ -48,6 +59,16 @@ MEMBERS_GROUP_ID = os.environ.get("MEMBERS_GROUP_ID", "")
 DB_PATH = os.environ.get("DB_PATH", "/app/data/members.db")
 
 
+def _verify_portal_secret(request: Request) -> None:
+    """Reject requests that didn't come through LibreChat (shared secret)."""
+    if not PORTAL_SECRET:
+        # If no secret is configured, refuse to inject keys (fail closed).
+        raise HTTPException(503, "Portal secret not configured")
+    provided = request.headers.get("x-portal-secret", "")
+    if not secrets.compare_digest(provided, PORTAL_SECRET):
+        raise HTTPException(401, "Invalid portal secret")
+
+
 def get_db() -> sqlite3.Connection:
     conn = sqlite3.connect(DB_PATH)
     conn.execute(
@@ -192,17 +213,18 @@ async def litellm_disable_key(key_token: str) -> None:
 
 # --- A. Open Collective webhook ---
 
-@app.post("/webhook/opencollective")
+@app.post("/webhook/opencollective/{token}")
-async def opencollective_webhook(request: Request):
+async def opencollective_webhook(request: Request, token: str):
-    """Handle Open Collective membership events."""
+    """Handle Open Collective membership events.
-    payload = await request.json()
 
-    # Verify webhook secret if configured
+    Authenticated by a secret token in the URL path (Open Collective's
-    if OPENCOLLECTIVE_SECRET:
+    generic webhooks are not HMAC-signed, so a secret URL is the standard
-        sig = request.headers.get("x-oc-signature", "")
+    way to authenticate them).
-        # TODO: verify HMAC signature
+    """
-        if not sig:
+    if not WEBHOOK_TOKEN or not secrets.compare_digest(token, WEBHOOK_TOKEN):
-            raise HTTPException(401, "Missing signature")
+        raise HTTPException(401, "Invalid webhook token")
+
+    payload = await request.json()
 
     event_type = payload.get("type", "")
     data = payload.get("data", {})
@@ -259,6 +281,10 @@ async def list_models():
 @app.api_route("/v1/{path:path}", methods=["GET", "POST", "PUT", "DELETE", "PATCH"])
 async def inject_key(request: Request, path: str):
     """Read the member's email from a header, inject their key, forward to LiteLLM."""
+    # Verify the request came through LibreChat (shared secret), so a direct
+    # caller can't spoof the X-User-Email header and use another member's key.
+    _verify_portal_secret(request)
+
     email = request.headers.get("x-user-email", "")
     if not email:
         raise HTTPException(401, "No member identity (x-user-email header)")