Fix cross-origin API access, bcrypt login break, and weak secret key

The frontend only worked from localhost:3000 — the browser made absolute
cross-origin calls to localhost:8000, which (a) points at the visitor's own
machine when accessed via the LAN IP or Cloudflare tunnel, and (b) was blocked
by CORS (backend only allowed localhost:3000). Now all API calls are
same-origin and proxied to the backend:

- api.ts: default API base to same-origin ("") instead of localhost:8000
- docker-compose: NEXT_PUBLIC_API_URL="" (client uses relative /api)
- next.config.ts: server-side rewrite uses API_INTERNAL_URL (http://backend:8000
  inside Docker) so :3000 direct access proxies correctly
- main.py: broaden CORS via allow_origin_regex (localhost + private LAN) and an
  optional CORS_ORIGINS env var, as defense-in-depth for direct :8000 access

Login was returning 500: passlib 1.7.4 is incompatible with the bcrypt 5.0.0
actually installed in the image (requirements pin 4.1.2, but the image drifted).
- security.py: call bcrypt directly, truncating to 72 bytes; existing $2b$
  hashes verify unchanged, and it works under both bcrypt 4.x and 5.x

Security: SECRET_KEY was a known placeholder string while the app is exposed on
the LAN and via Cloudflare tunnel — anyone could forge admin JWTs. Regenerated
to a strong random value in backend/.env (gitignored; not committed).

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

backend/app/core/config.py

@@ -13,6 +13,7 @@ class Settings(BaseSettings):
 
     SECRET_KEY: str = "dev-secret-key-change-in-production"
     ALGORITHM: str = "HS256"
+    CORS_ORIGINS: Optional[str] = None  # comma-separated extra allowed origins
     ACCESS_TOKEN_EXPIRE_MINUTES: int = 480
 
     AI_PROVIDER: str = "openai"

backend/app/core/security.py

@@ -1,21 +1,34 @@
 from datetime import datetime, timedelta
 from typing import Optional, Any
+import bcrypt
 from jose import JWTError, jwt
-from passlib.context import CryptContext
 from fastapi import HTTPException, status, Depends
 from fastapi.security import OAuth2PasswordBearer
 from app.core.config import settings
 
-pwd_context = CryptContext(schemes=["bcrypt"], deprecated="auto")
 oauth2_scheme = OAuth2PasswordBearer(tokenUrl=f"{settings.API_V1_STR}/auth/login")
 
+# We call bcrypt directly rather than through passlib: passlib 1.7.x is
+# incompatible with bcrypt >= 4.1 (its version shim raises on the modern
+# library). bcrypt only uses the first 72 bytes of a password, so we truncate
+# to that to avoid the ValueError bcrypt 5.x raises on longer inputs. Existing
+# $2b$ hashes (created via passlib's bcrypt backend) verify unchanged.
+_BCRYPT_MAX_BYTES = 72
+
+
+def _to_bytes(password: str) -> bytes:
+    return password.encode("utf-8")[:_BCRYPT_MAX_BYTES]
+
 
 def verify_password(plain: str, hashed: str) -> bool:
-    return pwd_context.verify(plain, hashed)
+    try:
+        return bcrypt.checkpw(_to_bytes(plain), hashed.encode("utf-8"))
+    except (ValueError, TypeError):
+        return False
 
 
 def hash_password(password: str) -> str:
-    return pwd_context.hash(password)
+    return bcrypt.hashpw(_to_bytes(password), bcrypt.gensalt()).decode("utf-8")
 
 
 def create_access_token(data: dict, expires_delta: Optional[timedelta] = None) -> str:

backend/app/main.py

@@ -22,9 +22,16 @@ app = FastAPI(
     lifespan=lifespan,
 )
 
+# The app is normally served same-origin (nginx proxies /api to the backend),
+# so CORS is not exercised in the primary flow. This allowlist exists for direct
+# browser access to :8000 during development and for any explicitly configured
+# origins. Extra origins can be added via the CORS_ORIGINS env var (comma-separated).
+_extra_origins = [o.strip() for o in (settings.CORS_ORIGINS or "").split(",") if o.strip()]
 app.add_middleware(
     CORSMiddleware,
-    allow_origins=["http://localhost:3000", "http://frontend:3000"],
+    allow_origins=["http://localhost:3000", "http://frontend:3000", *_extra_origins],
+    # Also allow localhost and private-network hosts on any port (dev convenience).
+    allow_origin_regex=r"^https?://(localhost|127\.0\.0\.1|10\.\d+\.\d+\.\d+|192\.168\.\d+\.\d+|172\.(1[6-9]|2\d|3[01])\.\d+\.\d+)(:\d+)?$",
     allow_credentials=True,
     allow_methods=["*"],
     allow_headers=["*"],

frontend/next.config.ts

@@ -5,7 +5,11 @@ const nextConfig: NextConfig = {
     return [
       {
         source: "/api/:path*",
-        destination: `${process.env.NEXT_PUBLIC_API_URL || "http://localhost:8000"}/api/:path*`,
+        // Server-side proxy for direct :3000 access. Uses the internal service
+        // hostname inside Docker (API_INTERNAL_URL=http://backend:8000); falls
+        // back to localhost for non-container dev. Not used when served via
+        // nginx, which proxies /api itself.
+        destination: `${process.env.API_INTERNAL_URL || "http://localhost:8000"}/api/:path*`,
       },
     ];
   },

frontend/src/lib/api.ts

@@ -1,4 +1,8 @@
-const BASE = process.env.NEXT_PUBLIC_API_URL || "http://localhost:8000";
+// Empty string = same-origin. API calls go to /api/... on whatever host served
+// the page, and are proxied to the backend by nginx (port 80) or the Next.js
+// rewrite in next.config.ts (port 3000). This keeps everything same-origin so
+// it works via localhost, the LAN IP, and the Cloudflare tunnel with no CORS.
+const BASE = process.env.NEXT_PUBLIC_API_URL ?? "";
 
 let authToken: string | null = null;
 

infra/docker-compose.yml

@@ -43,7 +43,10 @@ services:
       dockerfile: ../infra/Dockerfile.frontend
     container_name: trustos_frontend
     environment:
-      NEXT_PUBLIC_API_URL: http://localhost:8000
+      # Empty = same-origin API calls (proxied to backend by nginx / Next rewrite).
+      # Works via localhost, LAN IP, and Cloudflare tunnel without CORS.
+      NEXT_PUBLIC_API_URL: ""
+      API_INTERNAL_URL: "http://backend:8000"
     ports:
       - "3000:3000"
     volumes: