patch(fix #85): better XSS fix (#87)

* patch(fix #85): fixes xss vulnerability

* patch(fix #85): better XSS fix

package.json

@@ -1,6 +1,6 @@
 {
   "name": "mergely",
-  "version": "4.0.3",
+  "version": "4.0.5",
   "description": "A javascript UI for diff/merge",
   "directories": {
     "doc": "doc",

src/mergely.js

@@ -659,6 +659,13 @@ jQuery.extend(Mgly.CodeMirrorDiffView.prototype, {
 	bind: function(el) {
 		this.element.hide();
 		this.id = jQuery(el).attr('id');
+		try {
+			// ensure the id is valid for jQuery
+			jQuery(`#${this.id}`);
+		} catch (ex) {
+			console.error(`jQuery failed to find mergely: #${this.id}`);
+			return;
+		}
 		this.changed_timeout = null;
 		this.chfns = {};
 		this.chfns[this.id + '-lhs'] = [];
@@ -686,17 +693,32 @@ jQuery.extend(Mgly.CodeMirrorDiffView.prototype, {
 		// create the textarea and canvas elements
 		var height = '10px';
 		var width = '10px';
-		this.element.append(jQuery('<div id="mergely-splash">'));
-		this.element.append(jQuery('<div class="mergely-margin" style="height: ' + height + '"><canvas id="' + this.id + '-lhs-margin" width="8px" height="' + height + '"></canvas></div>'));
-		this.element.append(jQuery('<div style="position:relative;width:' + width + '; height:' + height + '" id="' + this.id + '-editor-lhs" class="mergely-column"><textarea style="" id="' + this.id + '-lhs"></textarea></div>'));
-		this.element.append(jQuery('<div class="mergely-canvas" style="height: ' + height + '"><canvas id="' + this.id + '-lhs-' + this.id + '-rhs-canvas" style="width:28px" width="28px" height="' + height + '"></canvas></div>'));
-		var rmargin = jQuery('<div class="mergely-margin" style="height: ' + height + '"><canvas id="' + this.id + '-rhs-margin" width="8px" height="' + height + '"></canvas></div>');
+
+		var splash = jQuery('<div id="mergely-splash">');
+		var canvasLhs = jQuery(`<div class="mergely-margin" style="height: '${height}'"><canvas id="lhs-margin" width="8px" height="'${height}'"></canvas></div>`);
+		canvasLhs.find('#lhs-margin').attr('id', `${this.id}-lhs-margin`);
+		var editorLhs = jQuery(`<div style="position:relative;width:'${width}'; height:'${height}'" id="editor-lhs" class="mergely-column"><textarea id="text-lhs"></textarea></div>`);
+		editorLhs.eq(0).attr('id', `${this.id}-editor-lhs`);
+		editorLhs.find('#text-lhs').attr('id', `${this.id}-lhs`);
+		var canvasMid = jQuery(`<div class="mergely-canvas" style="height: '${height}'"><canvas id="lhs-rhs-canvas" style="width:28px" width="28px" height="'${height}'"></canvas></div>`);
+		canvasMid.find('#mergely-canvas').attr('id', `${this.id}-mergely-canvas`);
+		canvasMid.find('#lhs-rhs-canvas').attr('id', `${this.id}-lhs-${this.id}-rhs-canvas`);
+
+		this.element.append(splash);
+		this.element.append(canvasLhs);
+		this.element.append(editorLhs);
+		this.element.append(canvasMid);
+		var canvasRhs = jQuery(`<div class="mergely-margin" style="height: '${height}'"><canvas id="rhs-margin" width="8px" height="'${height}'"></canvas></div>`);
+		canvasRhs.find('#rhs-margin').attr('id', `${this.id}-rhs-margin`);
 		if (this.settings.rhs_margin == 'left') {
-			this.element.append(rmargin);
+			this.element.append(canvasRhs);
 		}
-		this.element.append(jQuery('<div style="width:' + width + '; height:' + height + '" id="' + this.id + '-editor-rhs" class="mergely-column"><textarea style="" id="' + this.id + '-rhs"></textarea></div>'));
+		var editorRhs = jQuery(`<div style="width:'${width}'; height:'${height}'" id="editor-rhs" class="mergely-column"><textarea id="text-rhs"></textarea></div>`);
+		editorRhs.eq(0).attr('id', `${this.id}-editor-rhs`);
+		editorRhs.find('#text-rhs').attr('id', `${this.id}-rhs`);
+		this.element.append(editorRhs);
 		if (this.settings.rhs_margin != 'left') {
-			this.element.append(rmargin);
+			this.element.append(canvasRhs);
 		}
 		if (!this.settings.sidebar) {
 			this.element.find('.mergely-margin').css({display: 'none'});
@@ -734,32 +756,42 @@ jQuery.extend(Mgly.CodeMirrorDiffView.prototype, {
 			});
 		}
 
+		// check initialization
+		var rhstx;
+		try {
+			rhstx = this.element.find(`#${this.id}-rhs`).get(0);
+		} catch (ex) {
+		}
+		if (!rhstx) {
+			console.error('rhs textarea not defined - Mergely not initialized properly');
+			return;
+		}
+		var lhstx;
+		try {
+			lhstx = this.element.find(`#${this.id}-lhs`).get(0);
+		} catch (ex) {
+		}
+		if (!lhstx) {
+			console.error('lhs textarea not defined - Mergely not initialized properly');
+			return;
+		}
+
 		// get current diff border color
 		var color = jQuery('<div style="display:none" class="mergely current start" />').appendTo('body').css('border-top-color');
 		this.current_diff_color = color;
 
 		// codemirror
-		var cmstyle = '#' + this.id + ' .CodeMirror-gutter-text { padding: 5px 0 0 0; }' +
-			'#' + this.id + ' .CodeMirror-lines pre, ' + '#' + this.id + ' .CodeMirror-gutter-text pre { line-height: 18px; }' +
-			'.CodeMirror-linewidget { overflow: hidden; };';
+		var cmstyle = `#${this.id} .CodeMirror-gutter-text { padding: 5px 0 0 0; }
+			'#${this.id} .CodeMirror-lines pre, #${this.id} .CodeMirror-gutter-text pre { line-height: 18px; }
+			'.CodeMirror-linewidget { overflow: hidden; };`;
 		if (this.settings.autoresize) {
-			cmstyle += this.id + ' .CodeMirror-scroll { height: 100%; overflow: auto; }';
+			cmstyle += `${this.id} .CodeMirror-scroll { height: 100%; overflow: auto; }`;
 		}
 		// adjust the margin line height
 		cmstyle += '\n.CodeMirror { line-height: 18px; }';
-		jQuery('<style type="text/css">' + cmstyle + '</style>').appendTo('head');
+		jQuery(`<style type="text/css">${cmstyle}</style>`).appendTo('head');
 
-		//bind
-		var rhstx = this.element.find('#' + this.id + '-rhs').get(0);
-		if (!rhstx) {
-			console.error('rhs textarea not defined - Mergely not initialized properly');
-			return;
-		}
-		var lhstx = this.element.find('#' + this.id + '-lhs').get(0);
-		if (!rhstx) {
-			console.error('lhs textarea not defined - Mergely not initialized properly');
-			return;
-		}
+		// bind
 		var self = this;
 		this.editor = [];
 		this.editor[this.id + '-lhs'] = CodeMirror.fromTextArea(lhstx, this.lhs_cmsettings);

tests/mergely.spec.js

@@ -20,9 +20,10 @@ describe('mergely', function () {
 	};
 
 	afterEach(() => {
-		$('#mergely').mergely('unbind');
-		$('#mergely').mergelyUnregister();
-		$('#mergely').remove();
+		const mergely = $('#mergely');
+		mergely.mergely('unbind');
+		mergely.mergelyUnregister();
+		mergely.remove();
 	});
 
 	describe('initialization', () => {
@@ -524,5 +525,30 @@ describe('mergely', function () {
 				done();
 			});
 		});
+
+		it('should not be vulnerable to XSS', function (done) {
+			function initXSS(options) {
+				$('body').get(0).innerHTML = "<!DOCTYPE html><html lang=\"en\"><body><div id='mergely<script id=\"injected\">alert(123)</script>'></div></body></html>";
+				const divs = document.getElementsByTagName('div');
+				editor = $(divs[0]);
+				editor.mergely(options);
+				return editor;
+			};
+
+			$(document).ready(() => {
+				const editor = initXSS({
+					height: 100,
+					viewport: true,
+					license: 'lgpl-separate-notice',
+					lhs: (setValue) => setValue(macbeth),
+					rhs: (setValue) => setValue(macbeth)
+				});
+				expect($('body').find('#injected')).to.have.length(0, 'expected no div with id injected');
+				const divs = document.getElementsByTagName('div');
+				expect(divs).to.have.length(1);
+				expect(divs[0].id).to.equal('mergely<script id="injected">alert(123)</script>');
+				done();
+			});
+		});
 	});
 });