fix: enforce API request limits

Add a single platform-owned request-body policy (hono/body-limit) with
small, named limits for Better Auth and Core's grant-mutation endpoint, and
a new required maxBodyBytes field on the executable module route contract so
every module route makes a conscious no-body-or-bounded-body choice, capped
at a platform ceiling. Every oversized request gets one sanitized 413
contract and never reaches business logic, authorization, or a handler.
Also configure finite Node header/request/keep-alive timeouts, including the
non-obvious connectionsCheckingInterval needed for them to take effect
promptly, so a slow-header or slow-body connection cannot hold a socket
indefinitely.

Co-Authored-By: Claude Sonnet 5 <[email protected]>

apps/api/tests/grants-routes.test.ts

@@ -15,6 +15,7 @@ import {
 import type { EkklesiaIdentityRuntime } from "@ekklesia/core/identity";
 import { Hono } from "hono";
 import { describe, expect, it, vi } from "vitest";
+import { CORE_MUTATION_MAX_BODY_BYTES } from "../src/body-limits.js";
 import { createGrantsRoutes } from "../src/grants-routes.js";
 
 const trustedOrigin = "https://dashboard.example.test";
@@ -378,3 +379,136 @@ describe("POST /api/v1/grants/:grantId/revoke", () => {
     expect(await response.json()).toEqual({ code: "AUTHORIZATION_GRANT_REVOKE_FAILED" });
   });
 });
+
+describe("Core grant mutation request body limit", () => {
+  it("accepts a comfortably-under-limit grant-creation body and rejects one byte over the exact limit", async () => {
+    const store = fakeStore();
+    const { app } = buildApp({ store });
+
+    const overSizedBody = "a".repeat(CORE_MUTATION_MAX_BODY_BYTES + 1);
+    const overResponse = await app.request("/api/v1/grants", {
+      body: overSizedBody,
+      headers: {
+        "content-length": String(overSizedBody.length),
+        "content-type": "application/json",
+        origin: trustedOrigin,
+      },
+      method: "POST",
+    });
+    expect(overResponse.status).toBe(413);
+    expect(await overResponse.json()).toEqual({ code: "REQUEST_BODY_TOO_LARGE" });
+    expect(store.createGrant).not.toHaveBeenCalled();
+
+    // A well-formed, comfortably-under-limit payload still succeeds through the same route.
+    const underResponse = await app.request("/api/v1/grants", {
+      body: JSON.stringify({ permission: registeredPermission, subjectUserId }),
+      headers: { "content-type": "application/json", origin: trustedOrigin },
+      method: "POST",
+    });
+    expect(underResponse.status).not.toBe(413);
+  });
+
+  it("rejects an oversized declared Content-Length on grant creation without invoking permission evaluation", async () => {
+    const evaluatorAuthorize = vi.fn().mockResolvedValue({ allowed: true });
+    const evaluator: AuthorizationEvaluator = { authorize: evaluatorAuthorize };
+    const store = fakeStore();
+    const app = new Hono();
+    app.route(
+      "/",
+      createGrantsRoutes({
+        evaluator,
+        registry: CORE_PERMISSION_REGISTRY,
+        runtime: fakeRuntime(),
+        store,
+        trustedOrigins: new Set([trustedOrigin]),
+      }),
+    );
+
+    const response = await app.request("/api/v1/grants", {
+      body: "a",
+      headers: {
+        "content-length": String(CORE_MUTATION_MAX_BODY_BYTES * 10),
+        "content-type": "application/json",
+        origin: trustedOrigin,
+      },
+      method: "POST",
+    });
+
+    expect(response.status).toBe(413);
+    expect(evaluatorAuthorize).not.toHaveBeenCalled();
+    expect(store.createGrant).not.toHaveBeenCalled();
+  });
+
+  it("rejects an oversized streamed grant-creation body with no declared Content-Length", async () => {
+    const store = fakeStore();
+    const { app } = buildApp({ store });
+    const chunk = new Uint8Array(1024).fill(97);
+    let enqueued = 0;
+    const stream = new ReadableStream<Uint8Array>({
+      pull(controller) {
+        if (enqueued > CORE_MUTATION_MAX_BODY_BYTES) {
+          controller.close();
+          return;
+        }
+        enqueued += chunk.length;
+        controller.enqueue(chunk);
+      },
+    });
+
+    const response = await app.request("/api/v1/grants", {
+      body: stream,
+      duplex: "half",
+      headers: { "content-type": "application/json", origin: trustedOrigin },
+      method: "POST",
+    } as RequestInit);
+
+    expect(response.status).toBe(413);
+    expect(await response.json()).toEqual({ code: "REQUEST_BODY_TOO_LARGE" });
+    expect(store.createGrant).not.toHaveBeenCalled();
+  });
+
+  it("does not read an oversized body from an untrusted Origin: the trusted-origin rejection wins first", async () => {
+    const store = fakeStore();
+    const { app } = buildApp({ store });
+    const chunk = new Uint8Array(1024).fill(97);
+    let pullCount = 0;
+    const stream = new ReadableStream<Uint8Array>({
+      pull(controller) {
+        pullCount += 1;
+        if (pullCount > 3) {
+          controller.close();
+          return;
+        }
+        controller.enqueue(chunk);
+      },
+    });
+
+    const response = await app.request("/api/v1/grants", {
+      body: stream,
+      duplex: "half",
+      headers: { "content-type": "application/json", origin: untrustedOrigin },
+      method: "POST",
+    } as RequestInit);
+
+    expect(response.status).toBe(403);
+    expect(await response.json()).toEqual({ code: "UNTRUSTED_ORIGIN" });
+    expect(store.createGrant).not.toHaveBeenCalled();
+  });
+
+  it("also bounds the revoke mutation body", async () => {
+    const store = fakeStore();
+    const { app } = buildApp({ store });
+
+    const response = await app.request(`/api/v1/grants/${grantId}/revoke`, {
+      body: "a".repeat(CORE_MUTATION_MAX_BODY_BYTES + 1),
+      headers: {
+        "content-length": String(CORE_MUTATION_MAX_BODY_BYTES + 1),
+        origin: trustedOrigin,
+      },
+      method: "POST",
+    });
+
+    expect(response.status).toBe(413);
+    expect(store.revokeGrant).not.toHaveBeenCalled();
+  });
+});