141 lines
3.9 KiB
JavaScript
141 lines
3.9 KiB
JavaScript
const {ejs, ElemJS} = require("../basic")
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const {HighlightedCode} = require("./components")
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const DOMPurify = require("dompurify")
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const {resolveMxc} = require("../functions")
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const {MatrixEvent} = require("./event")
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const purifier = DOMPurify()
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purifier.addHook("uponSanitizeAttribute", (node, hookevent, config) => {
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// If purifier already rejected an attribute there is no point in checking it
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if (hookevent.keepAttr === false) return;
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const allowedElementAttributes = {
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"FONT": ["data-mx-bg-color", "data-mx-color", "color"],
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"SPAN": ["data-mx-bg-color", "data-mx-color"],
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"A": ["name", "target", "href"],
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"IMG": ["width", "height", "alt", "title", "src", "data-mx-emoticon"],
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"OL": ["start"],
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"CODE": ["class"],
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}
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const allowedAttributes = allowedElementAttributes[node.tagName] || []
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hookevent.keepAttr = allowedAttributes.indexOf(hookevent.attrName) > -1
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})
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purifier.addHook("uponSanitizeElement", (node, hookevent, config) => {
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// Remove bad classes from our code element
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if (node.tagName === "CODE") {
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node.classList.forEach(c => {
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if (!c.startsWith("language-")) {
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node.classList.remove(c)
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}
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})
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}
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if (node.tagName === "A") {
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node.setAttribute("rel", "noopener") // prevent the opening page from accessing carbon
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node.setAttribute("target", "_blank") // open in a new tab instead of replacing carbon
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}
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return node
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})
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function cleanHTML(html) {
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const config = {
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ALLOWED_TAGS: [
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"font", "del", "h1", "h2", "h3", "h4", "h5", "h6", "blockquote", "p",
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"a", "ul", "ol", "sup", "sub", "li", "b", "i", "u", "strong", "em",
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"strike", "code", "hr", "br", "div", "table", "thead", "tbody", "tr",
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"th", "td", "caption", "pre", "span", "img",
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// matrix tags
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"mx-reply"
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],
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// In case we mess up in the uponSanitizeAttribute hook
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ALLOWED_ATTR: [
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"color", "name", "target", "href", "width", "height", "alt", "title",
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"src", "start", "class", "noreferrer", "noopener",
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// matrix attrs
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"data-mx-emoticon", "data-mx-bg-color", "data-mx-color"
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],
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// Return a DOM fragment instead of a string, avoids potential future mutation XSS
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// should also be faster than the browser parsing HTML twice
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// https://research.securitum.com/mutation-xss-via-mathml-mutation-dompurify-2-0-17-bypass/
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RETURN_DOM_FRAGMENT: true,
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RETURN_DOM_IMPORT: true
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}
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return purifier.sanitize(html, config)
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}
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// Here we put all the processing of the messages that isn't as likely to potentially lead to security issues
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function postProcessElements(rootNode) {
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const element = rootNode.element
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element.querySelectorAll("pre").forEach(n => {
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new HighlightedCode(n)
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})
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element.querySelectorAll("img").forEach(n => {
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let src = n.getAttribute("src")
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if (src) src = resolveMxc(src)
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n.setAttribute("src", src)
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})
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element.querySelectorAll("font, span").forEach(n => {
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const color = n.getAttribute("data-mx-color") || n.getAttribute("color")
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const bgColor = n.getAttribute("data-mx-bg-color")
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if (color) n.style.color = color
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if (bgColor) n.style.backgroundColor = bgColor
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})
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}
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class HTMLMessage extends MatrixEvent {
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render() {
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this.clearChildren()
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let html = this.data.content.formatted_body
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const content = ejs("div")
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const fragment = cleanHTML(html)
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content.element.appendChild(fragment)
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postProcessElements(content)
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this.child(content)
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super.render()
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}
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static canRender(event) {
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const content = event.content
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return (
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event.type === "m.room.message"
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&& (content.msgtype === "m.text" || content.msgtype === "m.notice")
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&& content.format === "org.matrix.custom.html"
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&& content.formatted_body
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)
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}
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canGroup() {
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return true
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}
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}
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class TextMessage extends MatrixEvent {
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render() {
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this.clearChildren()
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this.text(this.data.content.body)
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super.render()
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}
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static canRender(event) {
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return event.type === "m.room.message"
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}
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canGroup() {
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return true
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}
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}
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module.exports = [HTMLMessage, TextMessage]
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