Merge branch 'branch-name-escape' into 'security'

Fix XSS in branches dropdown

See merge request !2093

app/assets/javascripts/gl_dropdown.js

@@ -610,7 +610,7 @@ GitLabDropdown = (function() {
       var link = document.createElement('a');
       link.href = url;
-      link.innerHTML = text;
+      link.textContent = text;
       if (selected) {
         link.className = 'is-active';

changelogs/unreleased/branch-name-escape.yml

+---
+title: Fixed branches dropdown rendering branch names as HTML
+merge_request:
+author:

spec/javascripts/gl_dropdown_spec.js

@@ -52,12 +52,8 @@ require('~/lib/utils/url_utility');
         search: {
           fields: ['name']
         },
-        text: (project) => {
-          (project.name_with_namespace || project.name);
-        },
-        id: (project) => {
-          project.id;
-        }
+        text: project => (project.name_with_namespace || project.name),
+        id: project => project.id
       });
     }
@@ -80,6 +76,18 @@ require('~/lib/utils/url_utility');
       expect(this.dropdownContainerElement).toHaveClass('open');
     });
+    it('escapes HTML as text', () => {
+      this.projectsData[0].name_with_namespace = '<script>alert("testing");</script>';
+
+      initDropDown.call(this, false);
+
+      this.dropdownButtonElement.click();
+
+      expect(
+        $('.dropdown-content li:first-child').text(),
+      ).toBe('<script>alert("testing");</script>');
+    });
+
     describe('that is open', () => {
       beforeEach(() => {
         initDropDown.call(this, false, false);