fix(media): bound input media payload sizes

src/media/input-files.fetch-guard.test.ts

@@ -0,0 +1,93 @@
+import { describe, expect, it, vi } from "vitest";
+
+const fetchWithSsrFGuardMock = vi.fn();
+
+vi.mock("../infra/net/fetch-guard.js", () => ({
+  fetchWithSsrFGuard: (...args: unknown[]) => fetchWithSsrFGuardMock(...args),
+}));
+
+describe("fetchWithGuard", () => {
+  it("rejects oversized streamed payloads and cancels the stream", async () => {
+    let canceled = false;
+    let pulls = 0;
+    const stream = new ReadableStream<Uint8Array>({
+      start(controller) {
+        controller.enqueue(new Uint8Array([1, 2, 3, 4]));
+      },
+      pull(controller) {
+        pulls += 1;
+        if (pulls === 1) {
+          controller.enqueue(new Uint8Array([5, 6, 7, 8]));
+        }
+        // keep stream open; cancel() should stop it once maxBytes exceeded
+      },
+      cancel() {
+        canceled = true;
+      },
+    });
+
+    const release = vi.fn(async () => {});
+    fetchWithSsrFGuardMock.mockResolvedValueOnce({
+      response: new Response(stream, {
+        status: 200,
+        headers: { "content-type": "application/octet-stream" },
+      }),
+      release,
+      finalUrl: "https://example.com/file.bin",
+    });
+
+    const { fetchWithGuard } = await import("./input-files.js");
+    await expect(
+      fetchWithGuard({
+        url: "https://example.com/file.bin",
+        maxBytes: 6,
+        timeoutMs: 1000,
+        maxRedirects: 0,
+      }),
+    ).rejects.toThrow("Content too large");
+
+    // Allow cancel() microtask to run.
+    await new Promise((resolve) => setTimeout(resolve, 0));
+
+    expect(canceled).toBe(true);
+    expect(release).toHaveBeenCalledTimes(1);
+  });
+});
+
+describe("base64 size guards", () => {
+  it("rejects oversized base64 images before decoding", async () => {
+    const data = Buffer.alloc(7).toString("base64");
+    const { extractImageContentFromSource } = await import("./input-files.js");
+    await expect(
+      extractImageContentFromSource(
+        { type: "base64", data, mediaType: "image/png" },
+        {
+          allowUrl: false,
+          allowedMimes: new Set(["image/png"]),
+          maxBytes: 6,
+          maxRedirects: 0,
+          timeoutMs: 1,
+        },
+      ),
+    ).rejects.toThrow("Image too large");
+  });
+
+  it("rejects oversized base64 files before decoding", async () => {
+    const data = Buffer.alloc(7).toString("base64");
+    const { extractFileContentFromSource } = await import("./input-files.js");
+    await expect(
+      extractFileContentFromSource({
+        source: { type: "base64", data, mediaType: "text/plain", filename: "x.txt" },
+        limits: {
+          allowUrl: false,
+          allowedMimes: new Set(["text/plain"]),
+          maxBytes: 6,
+          maxChars: 100,
+          maxRedirects: 0,
+          timeoutMs: 1,
+          pdf: { maxPages: 1, maxPixels: 1, minTextChars: 1 },
+        },
+      }),
+    ).rejects.toThrow("File too large");
+  });
+});