Add optional URL protection to createRegisterHandler (#148)

* validateAllowSaleorUrls impl

* Implement in handler and add test

* update codeowners

* Apply suggestions from code review

Co-authored-by: Krzysztof Wolski <krzysztof.k.wolski@gmail.com>

* Rename param

Co-authored-by: Krzysztof Wolski <krzysztof.k.wolski@gmail.com>

CODEOWNERS

@@ -1 +1 @@
-* @saleor/devtools
+* @saleor/marketplace

src/handlers/next/create-app-register-handler.test.ts

@@ -4,8 +4,6 @@ import { describe, expect, it, vi } from "vitest";
 import { APL } from "../../APL";
 import { createAppRegisterHandler } from "./create-app-register-handler";
 
-describe("create-app-register-handler", () => {
-  it("Sets auth data for correct request", async () => {
 vi.mock("../../get-app-id", () => ({
   getAppId: vi.fn().mockResolvedValue("42"),
 }));
@@ -27,6 +25,8 @@ describe("create-app-register-handler", () => {
   })),
 };
 
+describe("create-app-register-handler", () => {
+  it("Sets auth data for correct request", async () => {
     const { res, req } = createMocks({
       /**
        * Use body, instead of params, otherwise - for some reason - param is not accessible in mock request
@@ -61,4 +61,33 @@ describe("create-app-register-handler", () => {
       jwks: "{}",
     });
   });
+
+  it("Returns 403 if configured to work only for specific saleor URL and try to install on prohibited one", async () => {
+    const { res, req } = createMocks({
+      /**
+       * Use body, instead of params, otherwise - for some reason - param is not accessible in mock request
+       * Maybe this is a bug https://github.com/howardabrams/node-mocks-http/blob/master/lib/mockRequest.js
+       */
+      body: {
+        auth_token: "mock-auth-token",
+      },
+      headers: {
+        host: "some-saleor-host.cloud",
+        "x-forwarded-proto": "https",
+        "saleor-api-url": "https://wrong-saleor-domain.saleor.cloud/graphql/",
+        "saleor-domain": "https://wrong-saleor-domain.saleor.cloud/",
+      },
+      method: "POST",
+    });
+
+    const handler = createAppRegisterHandler({
+      apl: mockApl,
+      allowedSaleorUrls: [(url: string) => url === "https://mock-saleor-domain.saleor.cloud"],
+    });
+
+    await handler(req, res);
+
+    expect(res._getStatusCode()).toBe(403);
+    expect(res._getData().success).toBe(false);
+  });
 });

src/handlers/next/create-app-register-handler.ts

@@ -9,23 +9,48 @@ import { fetchRemoteJwks } from "../../fetch-remote-jwks";
 import { getAppId } from "../../get-app-id";
 import { withAuthTokenRequired, withSaleorDomainPresent } from "../../middleware";
 import { HasAPL } from "../../saleor-app";
+import { validateAllowSaleorUrls } from "./validate-allow-saleor-urls";
 
 const debug = createDebug("createAppRegisterHandler");
 
-export type CreateAppRegisterHandlerOptions = HasAPL;
+export type CreateAppRegisterHandlerOptions = HasAPL & {
+  /**
+   * Protect app from being registered in Saleor other than specific.
+   * By default, allow everything.
+   *
+   * Provide array of  either a full Saleor API URL (eg. my-shop.saleor.cloud/graphql/)
+   * or a function that receives a full Saleor API URL ad returns true/false.
+   */
+  allowedSaleorUrls?: Array<string | ((saleorApiUrl: string) => boolean)>;
+};
 
 /**
  * Creates API handler for Next.js. Creates handler called by Saleor that registers app.
  * Hides implementation details if possible
  * In the future this will be extracted to separate sdk/next package
  */
-export const createAppRegisterHandler = ({ apl }: CreateAppRegisterHandlerOptions) => {
+export const createAppRegisterHandler = ({
+  apl,
+  allowedSaleorUrls,
+}: CreateAppRegisterHandlerOptions) => {
   const baseHandler: Handler = async (request) => {
     debug("Request received");
     const authToken = request.params.auth_token;
     const saleorDomain = request.headers[SALEOR_DOMAIN_HEADER] as string;
     const saleorApiUrl = request.headers[SALEOR_API_URL_HEADER] as string;
 
+    if (!validateAllowSaleorUrls(saleorApiUrl, allowedSaleorUrls)) {
+      debug("Validation of URL %s against allowSaleorUrls param resolves to false, throwing");
+
+      return Response.Forbidden({
+        success: false,
+        error: {
+          code: "SALEOR_URL_PROHIBITED",
+          message: "This app expects to be installed only in allowed saleor instances",
+        },
+      });
+    }
+
     const { configured: aplConfigured } = await apl.isConfigured();
 
     if (!aplConfigured) {

src/handlers/next/validate-allow-saleor-urls.test.ts

@@ -0,0 +1,42 @@
+import { describe, expect, it } from "vitest";
+
+import { validateAllowSaleorUrls } from "./validate-allow-saleor-urls";
+
+const saleorCloudUrlMock = "https://my-shop.saleor.cloud/graphql/";
+const onPremiseSaleorUrlMock = "https://my-shop-123.aws-services.com/graphql/";
+
+const saleorCloudRegexValidator = (url: string) => /https:\/\/.*.saleor.cloud\/graphql\//.test(url);
+
+describe("validateAllowSaleorUrls", () => {
+  it("Passes any URL if allow list is empty", () => {
+    expect(validateAllowSaleorUrls(saleorCloudUrlMock, [])).toBe(true);
+    expect(validateAllowSaleorUrls(onPremiseSaleorUrlMock, [])).toBe(true);
+  });
+
+  it("Passes only for URL that was exactly matched in provided allow list array", () => {
+    expect(validateAllowSaleorUrls(saleorCloudUrlMock, [saleorCloudUrlMock])).toBe(true);
+    expect(validateAllowSaleorUrls(onPremiseSaleorUrlMock, [saleorCloudUrlMock])).toBe(false);
+  });
+
+  it("Validates against custom function provided to allow list", () => {
+    expect(validateAllowSaleorUrls(saleorCloudUrlMock, [saleorCloudRegexValidator])).toBe(true);
+    expect(validateAllowSaleorUrls(onPremiseSaleorUrlMock, [saleorCloudRegexValidator])).toBe(
+      false
+    );
+  });
+
+  it("Validates against more than one argument in allow list", () => {
+    expect(
+      validateAllowSaleorUrls(saleorCloudUrlMock, [
+        saleorCloudRegexValidator,
+        onPremiseSaleorUrlMock,
+      ])
+    ).toBe(true);
+    expect(
+      validateAllowSaleorUrls(onPremiseSaleorUrlMock, [
+        saleorCloudRegexValidator,
+        onPremiseSaleorUrlMock,
+      ])
+    ).toBe(true);
+  });
+});

src/handlers/next/validate-allow-saleor-urls.ts

@@ -0,0 +1,22 @@
+import { CreateAppRegisterHandlerOptions } from "./create-app-register-handler";
+
+export const validateAllowSaleorUrls = (
+  saleorApiUrl: string,
+  allowedUrls: CreateAppRegisterHandlerOptions["allowedSaleorUrls"]
+) => {
+  if (!allowedUrls || allowedUrls.length === 0) {
+    return true;
+  }
+
+  for (const urlOrFn of allowedUrls) {
+    if (typeof urlOrFn === "string" && urlOrFn === saleorApiUrl) {
+      return true;
+    }
+
+    if (typeof urlOrFn === "function" && urlOrFn(saleorApiUrl)) {
+      return true;
+    }
+  }
+
+  return false;
+};