feat(core): add missing ARIA attributes to html sanitizer

Allow ARIA attributes from the WAI-ARIA 1.1 spec which were stripped by the htmlSanitizer.

Closes angular#26815

packages/core/src/sanitization/html_sanitizer.ts

@@ -73,6 +73,16 @@ const HTML_ATTRS = tagSet(
     'scope,scrolling,shape,size,sizes,span,srclang,start,summary,tabindex,target,title,translate,type,usemap,' +
     'valign,value,vspace,width');
 
+// Accessibility attributes as per WAI-ARIA 1.1 (W3C Working Draft 14 December 2018)
+const ARIA_ATTRS = tagSet(
+    'aria-activedescendant,aria-atomic,aria-autocomplete,aria-busy,aria-checked,aria-colcount,aria-colindex,' +
+    'aria-colspan,aria-controls,aria-current,aria-describedby,aria-details,aria-disabled,aria-dropeffect,' +
+    'aria-errormessage,aria-expanded,aria-flowto,aria-grabbed,aria-haspopup,aria-hidden,aria-invalid,' +
+    'aria-keyshortcuts,aria-label,aria-labelledby,aria-level,aria-live,aria-modal,aria-multiline,' +
+    'aria-multiselectable,aria-orientation,aria-owns,aria-placeholder,aria-posinset,aria-pressed,aria-readonly,' +
+    'aria-relevant,aria-required,aria-roledescription,aria-rowcount,aria-rowindex,aria-rowspan,aria-selected,' +
+    'aria-setsize,aria-sort,aria-valuemax,aria-valuemin,aria-valuenow,aria-valuetext');
+
 // NB: This currently consciously doesn't support SVG. SVG sanitization has had several security
 // issues in the past, so it seems safer to leave it out if possible. If support for binding SVG via
 // innerHTML is required, SVG attributes should be added here.
@@ -81,7 +91,7 @@ const HTML_ATTRS = tagSet(
 // can be sanitized, but they increase security surface area without a legitimate use case, so they
 // are left out here.
 
-export const VALID_ATTRS = merge(URI_ATTRS, SRCSET_ATTRS, HTML_ATTRS);
+export const VALID_ATTRS = merge(URI_ATTRS, SRCSET_ATTRS, HTML_ATTRS, ARIA_ATTRS);
 
 // Elements whose content should not be traversed/preserved, if the elements themselves are invalid.
 //

packages/core/test/sanitization/html_sanitizer_spec.ts

@@ -52,6 +52,15 @@ import {_sanitizeHtml} from '../../src/sanitization/html_sanitizer';
           .toEqual('<main><summary>Works</summary></main>');
     });
 
+    it('supports ARIA attributes', () => {
+      expect(_sanitizeHtml(defaultDoc, '<h1 role="presentation" aria-haspopup="true">Test</h1>'))
+          .toEqual('<h1 role="presentation" aria-haspopup="true">Test</h1>');
+      expect(_sanitizeHtml(defaultDoc, '<i aria-label="Info">Info</i>'))
+          .toEqual('<i aria-label="Info">Info</i>');
+      expect(_sanitizeHtml(defaultDoc, '<img src="pteranodon.jpg" aria-details="details">'))
+          .toEqual('<img src="pteranodon.jpg" aria-details="details">');
+    });
+
     it('sanitizes srcset attributes', () => {
       expect(_sanitizeHtml(defaultDoc, '<img srcset="/foo.png 400px, javascript:evil() 23px">'))
           .toEqual('<img srcset="/foo.png 400px, unsafe:javascript:evil() 23px">');