fix(core): serialise attachment file mutations, atomic writes, reject svg

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

packages/core/test/attachments.test.ts

@@ -105,4 +105,69 @@ forEachDialect("attachments", (getDb) => {
     expect(await filesUnder(join(dataDir, "attachments"))).toHaveLength(0);
     expect(await db.k.selectFrom("attachments").selectAll().execute()).toHaveLength(0);
   });
+
+  test("rejects svg and normalizes mime", async () => {
+    const db = getDb();
+    const u = await addUser(db, "u1");
+    const link = { entity: "work", entityId: "w1" } as const;
+    for (const mime of ["image/svg+xml", "IMAGE/SVG+XML; charset=utf-8"]) {
+      await expect(storeAttachment(db, dataDir, u, { ...png("x"), mime }, link)).rejects.toBeInstanceOf(
+        ValidationError,
+      );
+    }
+    const a = await storeAttachment(db, dataDir, u, { ...png("x"), mime: "Image/PNG; foo=bar" }, link);
+    expect(a.mime).toBe("image/png");
+    expect((await listAttachments(db, u, "work", "w1"))[0]?.mime).toBe("image/png");
+  });
+
+  test("shared bytes across users survive the other's unlink", async () => {
+    const db = getDb();
+    const ua = await addUser(db, "a");
+    const ub = await addUser(db, "b");
+    const a = await storeAttachment(db, dataDir, ua, png("same"), { entity: "work", entityId: "w1" });
+    const b = await storeAttachment(db, dataDir, ub, png("same"), { entity: "work", entityId: "w1" });
+    await unlinkAttachment(db, dataDir, ua, a.id, "work", "w1");
+    expect(await filesUnder(join(dataDir, "attachments"))).toHaveLength(1);
+    const r = await readAttachment(db, dataDir, ub, b.id);
+    expect(await r?.file.text()).toBe("same");
+  });
+
+  test("another user's unlink is a no-op", async () => {
+    const db = getDb();
+    const ua = await addUser(db, "a");
+    const ub = await addUser(db, "b");
+    const a = await storeAttachment(db, dataDir, ua, png("mine"), { entity: "work", entityId: "w1" });
+    await unlinkAttachment(db, dataDir, ub, a.id, "work", "w1");
+    expect(await listAttachments(db, ua, "work", "w1")).toHaveLength(1);
+    expect(await filesUnder(join(dataDir, "attachments"))).toHaveLength(1);
+  });
+
+  test("listAttachments is scoped to the user", async () => {
+    const db = getDb();
+    const ua = await addUser(db, "a");
+    const ub = await addUser(db, "b");
+    await storeAttachment(db, dataDir, ua, png("one"), { entity: "work", entityId: "w1" });
+    expect(await listAttachments(db, ub, "work", "w1")).toHaveLength(0);
+    expect(await listAttachments(db, ua, "work", "w1")).toHaveLength(1);
+  });
+
+  test("concurrent store and unlink never leave a row without its file", async () => {
+    const db = getDb();
+    const u = await addUser(db, "u1");
+    const first = await storeAttachment(db, dataDir, u, png("race"), { entity: "work", entityId: "w1" });
+    const [, second] = await Promise.all([
+      unlinkAttachment(db, dataDir, u, first.id, "work", "w1"),
+      storeAttachment(db, dataDir, u, png("race"), { entity: "work", entityId: "w2" }),
+    ]);
+    const r = await readAttachment(db, dataDir, u, second.id);
+    expect(await r?.file.text()).toBe("race");
+  });
+
+  test("leaves no temp files behind", async () => {
+    const db = getDb();
+    const u = await addUser(db, "u1");
+    await storeAttachment(db, dataDir, u, png("clean"), { entity: "work", entityId: "w1" });
+    const files = await filesUnder(join(dataDir, "attachments"));
+    expect(files.some((f) => f.includes(".tmp-"))).toBe(false);
+  });
 });

packages/core/test/crypto.test.ts

@@ -23,4 +23,17 @@ describe("crypto", () => {
     await expect(decryptJson("k", "garbage")).rejects.toBeInstanceOf(CryptoError);
     await expect(decryptJson("k", "v2.AA==.AA==")).rejects.toBeInstanceOf(CryptoError);
   });
+
+  test("IV decodes to 12 bytes", async () => {
+    const blob = await encryptJson("k", { a: 1 });
+    expect(Buffer.from(blob.split(".")[1]!, "base64")).toHaveLength(12);
+  });
+
+  test("flipping a ciphertext byte throws CryptoError", async () => {
+    const [v, iv, ct] = (await encryptJson("k", { a: 1 })).split(".");
+    const bytes = Buffer.from(ct!, "base64");
+    bytes[0] = bytes[0]! ^ 0xff;
+    const tampered = `${v}.${iv}.${bytes.toString("base64")}`;
+    await expect(decryptJson("k", tampered)).rejects.toBeInstanceOf(CryptoError);
+  });
 });