fix(connectors): allowlist provider authorization endpoints

server/src/services/paperclip-cloud-connector.test.ts

@@ -115,11 +115,35 @@ describe("Paperclip Cloud connector", () => {
     });
   });
 
+  it("accepts the fixed Google authorization endpoint for Google profiles", async () => {
+    const keys = config();
+    const connector = createPaperclipCloudConnector({
+      config: keys.config,
+      request: vi.fn(async () => Response.json({
+        confirmationUrl: "https://my.example.test/connections/confirm?session=broker-state",
+        authorizationUrl: "https://accounts.google.com/o/oauth2/v2/auth?client_id=client&state=broker-state",
+        expiresAt: "2099-08-21T20:00:00.000Z",
+      })) as typeof fetch,
+    });
+
+    await expect(connector.startAuthorization({
+      subject,
+      companyId,
+      profile: "gmail.draft",
+      returnUri: "https://paperclip.example.test/api/tools/oauth/cloud-connector/callback",
+      returnState: "state-direct-google",
+    })).resolves.toMatchObject({
+      authorizationUrl: "https://accounts.google.com/o/oauth2/v2/auth?client_id=client&state=broker-state",
+    });
+  });
+
   it.each([
     ["non-string", { href: "https://github.com/login/oauth/authorize" }],
     ["plaintext HTTP", "http://github.com/login/oauth/authorize"],
     ["embedded credentials", "https://user:password@github.com/login/oauth/authorize"],
     ["fragment", "https://github.com/login/oauth/authorize#unexpected"],
+    ["unapproved HTTPS origin", "https://attacker.example.test/login/oauth/authorize"],
+    ["unapproved provider path", "https://github.com/session/authorize"],
     ["not a URL", "not-a-url"],
   ])("rejects a malformed direct provider URL: %s", async (_label, authorizationUrl) => {
     const keys = config();

server/src/services/paperclip-cloud-connector.ts

@@ -380,6 +380,7 @@ export function createPaperclipCloudConnector(input: {
           || authorizationUrl.username
           || authorizationUrl.password
           || authorizationUrl.hash
+          || !isExpectedProviderAuthorizationUrl(profile, authorizationUrl)
         ) {
           throw new PaperclipCloudConnectorError("Paperclip Cloud connector returned an invalid provider URL", "CONNECTOR_BAD_RESPONSE");
         }
@@ -678,6 +679,16 @@ function connectorProfileDefinition(profile: PaperclipCloudConnectorProfileId):
   return { provider: "google", scopes: GOOGLE_WORKSPACE_CONNECTOR_PROFILES[profile].scopes };
 }
 
+function isExpectedProviderAuthorizationUrl(
+  profile: PaperclipCloudConnectorProfileId,
+  url: URL,
+): boolean {
+  if (isGitHubConnectorProfileId(profile)) {
+    return url.origin === "https://github.com" && url.pathname === "/login/oauth/authorize";
+  }
+  return url.origin === "https://accounts.google.com" && url.pathname === "/o/oauth2/v2/auth";
+}
+
 function isPaperclipCloudConnectorProfileId(value: string): value is PaperclipCloudConnectorProfileId {
   return isGoogleWorkspaceConnectorProfileId(value) || isGitHubConnectorProfileId(value);
 }