freezmo/app/api/grade/route.ts
Martin Dvorak 8822baf4b7 Security: model budget + concurrency caps, SSRF guards, spoof-proof limits
Audit pass with the threats that actually apply to a self-hosted, account-less
app: getting the Ollama key throttled or banned, and someone grinding the app
down. Per-route windows already existed; these are the missing layers.

- lib/model-guard.ts: every route that spends a model call now takes a slot —
  60 calls per window across all clients (RATE_LIMIT_MODEL_TOTAL), 3 in flight
  per IP, 6 in total — and the slot is released when the call finishes, on
  errors and on client disconnects. Over the concurrency cap answers 429
  kind=busy, not a punishment. Slots are taken after every cheap rejection so
  a malformed request cannot hold one (found by the new suite: early 400s
  were leaking slots).
- Images must be base64 data URLs (dataUrlSchema in lib/schemas): a plain URL
  in an images field made Ollama fetch an arbitrary address on our behalf.
- Push endpoints must be a real push service (PUSH_ALLOWED_HOSTS, defaulting
  to FCM/Mozilla/Apple/WNS): the server POSTs to whatever is stored.
- The rate-limit identity is the LAST x-forwarded-for hop. Reading the first
  let a client spoof its own IP and dodge every per-IP limit.
- Disk guards: reports.jsonl stops at REPORTS_MAX_BYTES (8 MB), reminder
  devices cap at PUSH_MAX_SUBSCRIPTIONS (50).
- Security headers: frame-ancestors 'none' + X-Frame-Options DENY, nosniff, a
  referrer policy and a Permissions-Policy without camera/mic/geo/payment.

New tests/security-test.mjs (13 checks, registered in run-all) proves each
guard against a slow stub Ollama with deliberately tiny limits. README:
security notes + rate-limit tables updated. Version 0.1.3, SW -> v51.
2026-10-12 20:40:57 +00:00

81 lines
2.8 KiB
TypeScript

import { z } from "zod";
import { gradeShortAnswer } from "@/lib/ai";
import { authErrorMessage, authErrorKind, getServerConfig, resolveAuth } from "@/lib/config";
import { friendlyErrorMessage, OllamaError } from "@/lib/ollama";
import { rejectCrossOrigin, rejectOversizedBody, requestLocale } from "@/lib/http-guard";
import { clientKey, rateLimit, rateLimitResponse } from "@/lib/rate-limit";
import { acquireModelGate } from "@/lib/model-guard";
import { translate } from "@/lib/i18n-dict";
export const runtime = "nodejs";
export const dynamic = "force-dynamic";
const requestSchema = z.object({
question: z.string().min(1).max(1000),
referenceAnswer: z.string().min(1).max(2000),
keyPoints: z.array(z.string().max(300)).max(8).default([]),
userAnswer: z.string().min(1).max(2000),
/** Language of the deck so feedback comes back in the same language. */
language: z.string().max(60).optional(),
});
/** Generous but finite: ~16 compressed images plus JSON overhead. */
const MAX_BODY_BYTES = 65536;
export async function POST(request: Request) {
const locale = requestLocale(request);
const crossOrigin = rejectCrossOrigin(request);
if (crossOrigin) return crossOrigin;
const oversized = rejectOversizedBody(request, MAX_BODY_BYTES);
if (oversized) return oversized;
const config = getServerConfig();
const limit = rateLimit(`grade:${clientKey(request)}`, config.rateLimits.grade, config.rateLimits.windowMs);
if (!limit.allowed) return rateLimitResponse(limit, locale);
const auth = resolveAuth(config, request);
if ("error" in auth) {
return Response.json(
{ error: authErrorMessage(locale, auth.error), kind: authErrorKind(auth.error) },
{ status: 401 },
);
}
let payload: unknown;
try {
payload = await request.json();
} catch {
return Response.json({ error: translate(locale, "server.bodyNotJson") }, { status: 400 });
}
const parsed = requestSchema.safeParse(payload);
if (!parsed.success) {
return Response.json({ error: translate(locale, "server.invalidGrade") }, { status: 400 });
}
const gate = acquireModelGate(request, config, locale);
if ("response" in gate) return gate.response;
try {
const result = await gradeShortAnswer({
model: config.textModel,
auth: auth.auth,
...parsed.data,
// Grading is quick; don't let a hung request block the feed for minutes.
signal: AbortSignal.timeout(Math.min(config.timeoutMs, 120_000)),
});
return Response.json(result);
} catch (error) {
console.error("[api/grade]", error instanceof OllamaError ? `${error.kind}: ${error.message}` : error);
return Response.json(
{
error: friendlyErrorMessage(error, auth.auth.baseUrl, locale),
kind: error instanceof OllamaError ? error.kind : "unknown",
},
{ status: 502 },
);
} finally {
gate.gate.release();
}
}