fix(pages): reject devtools:// URLs in navigate_page and new_page (#2935) (#3128)

Reject navigations to `devtools:` URLs. The rejection is unconditional:
no flag or option enables `devtools:` navigations.

The check is in `validateUrl` in `src/utils/url.ts`. These tools call
`validateUrl` and reject `devtools:` URLs:

- `navigate_page` (`src/tools/pages.ts`)
- `new_page` (`src/tools/pages.ts`)
- the slim `navigate` tool (`src/tools/slim/tools.ts`)

The error message is `Navigating to devtools: URLs is not allowed.`

Closes #2935

---------

Co-authored-by: Alex Rudenko <alexrudenko@chromium.org>

src/utils/url.ts

@@ -264,6 +264,10 @@ export function validateUrl(url: string, options: ValidateUrlOptions): URL {
     );
   }
 
+  if (parsed.protocol === 'devtools:') {
+    throw new Error(`Navigating to devtools: URLs is not allowed.`);
+  }
+
   if (!isAllowedUrl(url, {categoryExtensions})) {
     if (parsed.protocol === 'chrome-extension:') {
       throw new Error(

tests/utils/url.test.ts

@@ -318,6 +318,17 @@ describe('validateUrl', () => {
     );
   });
 
+  it('should reject devtools: URLs', () => {
+    assert.throws(
+      () =>
+        validateUrl(
+          'devtools://devtools/bundled/devtools_app.html',
+          defaultOptions,
+        ),
+      /Navigating to devtools: URLs is not allowed\./,
+    );
+  });
+
   it('should allow file URLs when fileNavigations is true or omitted', () => {
     assert.strictEqual(
       validateUrl('file:///tmp/example.txt', defaultOptions).protocol,