Remove xss attack; closes #1443 at least partially

browser/lib/markdown-it-sanitize-html.js

@@ -0,0 +1,23 @@
+'use strict'
+
+import sanitizeHtml from 'sanitize-html'
+
+module.exports = function sanitizePlugin (md, options) {
+  options = options || {}
+
+  md.core.ruler.after('linkify', 'sanitize_inline', state => {
+    for (let tokenIdx = 0; tokenIdx < state.tokens.length; tokenIdx++) {
+      if (state.tokens[tokenIdx].type === 'html_block') {
+        state.tokens[tokenIdx].content = sanitizeHtml(state.tokens[tokenIdx].content, options)
+      }
+      if (state.tokens[tokenIdx].type === 'inline') {
+        const inlineTokens = state.tokens[tokenIdx].children
+        for (let childIdx = 0; childIdx < inlineTokens.length; childIdx++) {
+          if (inlineTokens[childIdx].type === 'html_inline') {
+            inlineTokens[childIdx].content = sanitizeHtml(inlineTokens[childIdx].content, options)
+          }
+        }
+      }
+    }
+  })
+}

browser/lib/markdown.js

@@ -1,4 +1,5 @@
 import markdownit from 'markdown-it'
+import sanitize from './markdown-it-sanitize-html'
 import emoji from 'markdown-it-emoji'
 import math from '@rokt33r/markdown-it-math'
 import _ from 'lodash'
@@ -46,6 +47,16 @@ var md = markdownit({
       '</code></pre>'
   }
 })
+// Sanitize use rinput before other plugins
+md.use(sanitize, {
+  allowedTags: ['img', 'iframe'],
+  allowedAttributes: {
+    '*': ['alt', 'style'],
+    'img': ['src', 'height', 'width'],
+    'iframe': ['src']
+  },
+  allowedIframeHostnames: ['www.youtube.com']
+})
 md.use(emoji, {
   shortcuts: {}
 })