Replace SvelteKit CSRF with custom multi-origin check

SvelteKit's built-in CSRF only allows one origin, breaking access via
NetBird/Yggdrasil/Tor IPs. Now:
- Disabled checkOrigin in svelte.config.js
- Custom CSRF in hooks.server.ts checks Origin against ALLOWED_ORIGINS
- ALLOWED_ORIGINS env var: comma-separated list of trusted origins
- Caddy no longer needs to rewrite Host/Origin headers
- Each access method (public domain, NetBird IP, Yggdrasil, Tor onion)
  just needs its URL added to ALLOWED_ORIGINS

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

.env.example

@@ -1,4 +1,6 @@
 DATABASE_URL=postgresql://bflr:bflr_dev@localhost:5432/buildfor_life_repair
 UPLOAD_DIR=static/uploads
 BASE_URL=http://localhost:5173
+ORIGIN=https://collection.newedge.house
+ALLOWED_ORIGINS=https://collection.newedge.house,http://100.81.174.129
 BODY_SIZE_LIMIT=52428800

docs/caddy-reverse-proxy.md

@@ -19,7 +19,7 @@ Tor      ──► .onion ──► tor ──► :8880 ──┤
                                         └─────────────────────────────────┘
 ```
 
-All routes inject `Host: collection.newedge.house` so SvelteKit CSRF passes.
+CSRF is handled by the app via `ALLOWED_ORIGINS` env var — no header rewriting needed.
 
 ## 1. Install Caddy and Tor
 
@@ -75,8 +75,6 @@ Edit `/etc/caddy/Caddyfile`:
 
 (proxy) {
 	reverse_proxy 127.0.0.1:3000 {
-		header_up Host collection.newedge.house
-		header_up Origin https://collection.newedge.house
 		header_up X-Real-IP {remote_host}
 		header_up X-Forwarded-For {remote_host}
 		header_up X-Forwarded-Proto https
@@ -164,6 +162,7 @@ HOST=127.0.0.1
 PORT=3000
 ORIGIN=https://collection.newedge.house
 BASE_URL=https://collection.newedge.house
+ALLOWED_ORIGINS=https://collection.newedge.house,http://100.x.x.x,http://[200:xxxx:...],http://your-onion.onion
 ```
 
 systemd service:

src/hooks.server.ts

@@ -1,21 +1,47 @@
 import type { Handle, HandleServerError } from '@sveltejs/kit';
 import { validateSession, setSessionCookie, deleteSessionCookie } from '$lib/server/auth/index.js';
+import { env } from '$env/dynamic/private';
+import { error } from '@sveltejs/kit';
 
-export const handleError: HandleServerError = async ({ error }) => {
-	const message = error instanceof Error ? error.message : 'Unknown error';
+export const handleError: HandleServerError = async ({ error: err }) => {
+	const message = err instanceof Error ? err.message : 'Unknown error';
 
-	// Body size limit exceeded
 	if (message.includes('exceeds limit')) {
 		return {
 			message: 'File too large. Maximum upload size is 50MB.'
 		};
 	}
 
-	console.error('Unhandled error:', error);
+	console.error('Unhandled error:', err);
 	return { message: 'An unexpected error occurred.' };
 };
 
+// Trusted origins for CSRF — set ALLOWED_ORIGINS in .env as comma-separated list
+// e.g. ALLOWED_ORIGINS=https://collection.newedge.house,http://100.81.174.129
+function getAllowedOrigins(): Set<string> {
+	const origins = new Set<string>();
+
+	if (env.ORIGIN) origins.add(env.ORIGIN);
+	if (env.BASE_URL) origins.add(env.BASE_URL);
+
+	const extra = env.ALLOWED_ORIGINS?.split(',').map((o) => o.trim()).filter(Boolean);
+	if (extra) for (const o of extra) origins.add(o);
+
+	return origins;
+}
+
 export const handle: Handle = async ({ event, resolve }) => {
+	// CSRF check for non-GET requests
+	if (event.request.method !== 'GET' && event.request.method !== 'HEAD') {
+		const origin = event.request.headers.get('origin');
+		if (origin) {
+			const allowed = getAllowedOrigins();
+			if (allowed.size > 0 && !allowed.has(origin)) {
+				error(403, 'Cross-site request blocked');
+			}
+		}
+	}
+
 	const token = event.cookies.get('session');
 
 	if (token) {
@@ -25,7 +51,6 @@ export const handle: Handle = async ({ event, resolve }) => {
 			event.locals.user = user;
 			event.locals.session = session;
 
-			// Refresh cookie if session was extended
 			if (session.fresh) {
 				setSessionCookie(event, token, session.expiresAt);
 			}

svelte.config.js

@@ -15,7 +15,10 @@ const config = {
 		adapter: adapter({
 			out: 'build',
 			precompress: true
-		})
+		}),
+		csrf: {
+			checkOrigin: false
+		}
 	}
 };