diff --git a/lib/channel/customization.js b/lib/channel/customization.js
index 627c9ae3..1ed7df8c 100644
--- a/lib/channel/customization.js
+++ b/lib/channel/customization.js
@@ -36,9 +36,11 @@ CustomizationModule.prototype.load = function (data) {
if ("motd" in data) {
this.motd = {
- motd: data.motd.motd || "",
- html: data.motd.html || ""
+ motd: data.motd.motd || ""
};
+
+ this.motd.motd = XSS.sanitizeHTML(this.motd.motd);
+ this.motd.html = this.motd.motd.replace(/\n/g, "
");
}
};
diff --git a/lib/xss.js b/lib/xss.js
index 9b02ce2b..c6c0de2e 100644
--- a/lib/xss.js
+++ b/lib/xss.js
@@ -1,260 +1,62 @@
-/*
- WARNING
+var sanitizeHTML = require("sanitize-html");
- This file contains an XSS prevention module I wrote myself. It has not
- been verified by any external agency, and due to the nature of XSS I cannot
- guarantee that it will filter correctly. Feel free to send me bug reports
- and I will do my best to fix them, but use at your own risk.
+const ALLOWED_TAGS = [
+ "button",
+ "center",
+ "details",
+ "font",
+ "h1",
+ "h2",
+ "img",
+ "marquee", // It pains me to do this, but a lot of people use it...
+ "section",
+ "span",
+ "summary"
+];
-*/
-
-/* Prototype for a basic XML tag parser */
-function TagParser(text) {
- this.text = text;
- this.i = 0;
- this.tag = this.parse();
-}
-
-/* Moves the position marker past any whitespace characters */
-TagParser.prototype.skipWhitespace = function () {
- while (this.i < this.text.length && this.text[this.i].match(/\s/)) {
- this.i++;
- }
-};
-
-/* Reads a literal value matching the given regexp. Defaults
- to /[^\s>]/; i.e. any string not containing whitespace or
- the end of tag character '>'
-*/
-TagParser.prototype.readLiteral = function (regexp) {
- if (regexp === void 0) {
- regexp = /[^\s>]/;
- }
- var str = "";
- while (this.i < this.text.length && this.text[this.i].match(regexp)) {
- str += this.text[this.i];
- this.i++;
- }
-
- str = str.replace(/&#([0-9]{2,7});?/g, function (m, p1) {
- return String.fromCharCode(parseInt(p1));
- });
-
- str = str.replace(/&#x([0-9a-fA-F]{2,7});?/g, function (m, p1) {
- return String.fromCharCode(parseInt(p1, 16));
- });
-
- str = str.replace(/[\x00-\x1f]/g, "");
- return str;
-};
-
-/* If the character at the current position is a quote, read
- a string. Otherwise, read a literal
-*/
-TagParser.prototype.readLiteralOrString = function (regexp) {
- if (this.text[this.i].match(/["'`]/)) {
- return this.readString();
- }
- return this.readLiteral(regexp);
-};
-
-/* Read a string delimited by the character at the current
- position. For XML tags this means strings enclosed in
- " or '. Treats \" as a literal '"' symbol and not a
- delimiter.
-*/
-TagParser.prototype.readString = function () {
- var delim = this.text[this.i++];
-
- var str = "";
- while (this.i < this.text.length && this.text[this.i] !== delim) {
- if (this.text[this.i] === "\\" && this.text[this.i+1] === delim) {
- str += this.text[this.i+1];
- this.i++;
- } else {
- str += this.text[this.i];
- }
- this.i++;
- }
- this.i++;
-
- str = str.replace(/&#([0-9]{2,7});?/g, function (m, p1) {
- return String.fromCharCode(parseInt(p1));
- });
-
- str = str.replace(/&#x([0-9a-fA-F]{2,7});?/g, function (m, p1) {
- return String.fromCharCode(parseInt(p1, 16));
- });
-
- str = str.replace(/[\x00-\x1f]/g, "");
- return str;
-};
-
-/* Attempts to parse a tagname and attributes from an
- XML tag.
- NOTE: Does not actually parse a DOM node, only parses
- the tag between '<' and '>' because that's all I need
- to do XSS filtering, I don't care what's between a tag
- and its end tag (if it's another tag I handle that
- separately)
-*/
-TagParser.prototype.parse = function () {
- this.i = this.text.indexOf("<");
- // Not a tag
- if (this.i === -1) {
- return null;
- }
-
- this.i++;
- this.skipWhitespace();
-
- // First non-whitespace string after the opening '<' is the tag name
- var tname = this.readLiteral();
-
- var attrs = {};
- // Continue parsing attributes until the end of string is reached or
- // the end of tag is reached
- while (this.i < this.text.length && this.text[this.i] !== ">") {
- // Read any string not containing equals, possibly delimited by
- // " or '
- var key = this.readLiteralOrString(/[^\s=>]/);
- this.skipWhitespace();
- // It's possible for tags to have attributes with no value, where
- // the equals sign is not necessary
- if (this.text[this.i] !== "=") {
- if (key.trim().length > 0) {
- attrs[key] = "";
- }
- continue;
- }
-
- this.i++;
- //this.skipWhitespace();
- var value = this.readLiteralOrString();
- if (key.trim().length > 0) {
- attrs[key] = value;
- }
- this.skipWhitespace();
- }
-
- // If end-of-string was not reached, consume the ending '>'
- if (this.i < this.text.length) {
- this.i++;
- }
-
- return {
- tagName: tname,
- attributes: attrs,
- text: this.text.substring(0, this.i) // Original text (for replacement)
- };
-};
-
-/* Some of these may not even be HTML tags, I borrowed them from the
- [now deprecated] XSS module of node-validator
-*/
-const badTags = new RegExp([
- "alert",
- "applet",
- "audio",
- "basefont",
- "base",
- "behavior",
- "bgsound",
- "blink",
- "body",
- "embed",
- "expression",
- "form",
- "frameset",
- "frame",
- "head",
- "html",
- "ilayer",
- "iframe",
- "input",
- "layer",
- "link",
- "meta",
- "object",
+const ALLOWED_ATTRIBUTES = [
+ "id",
+ "aria-hidden",
+ "border",
+ "class",
+ "color",
+ "data-dismiss",
+ "data-target",
+ "height",
+ "role",
"style",
- "script",
- "textarea",
"title",
- "video",
- "xml",
- "xss"
-].join("|"), "i");
+ "valign",
+ "width"
+];
-/* Nasty attributes. Anything starting with "on" is probably a javascript
- callback, and I hope you see why formaction is a bad idea.
-*/
-const badAttrs = new RegExp([
- "\\bon\\S*",
- "\\bformaction",
- "\\baction"
-].join("|"), "i");
-
-function sanitizeHTML(str) {
- var i = str.indexOf("<");
- if (i === -1) {
- // No HTML tags in the string
- return str;
- }
-
- // Loop across all tag delimiters '<' in string, parse each one,
- // and replace the results with sanitized tags
- while (i !== -1) {
- var t = new TagParser(str.substring(i)).tag;
- if (t.tagName.replace("/", "").match(badTags)) {
- // Note: Important that I replace the tag with a nonempty value,
- // otherwise ipt> would possibly defeat the filter.
- str = str.replace(t.text, "[tag removed]");
- i = str.indexOf("<", i+1);
- continue;
- }
- for (var k in t.attributes) {
- // Keys should not contain non-word characters.
- var k2 = k.replace(/[^\w]/g, "");
- if (k2 !== k) {
- t.attributes[k2] = t.attributes[k];
- delete t.attributes[k];
- k = k2;
- }
- // If it's an evil attribute, just nuke it entirely
- if (k.match(badAttrs)) {
- delete t.attributes[k];
- } else {
- if (t.attributes[k].replace(/\s/g, "").indexOf("javascript:") !== -1) {
- t.attributes[k] = "[removed]";
- }
-
- }
- }
- // Build the sanitized tag
- var fmt = "<" + t.tagName;
- for (var k in t.attributes) {
- if (k.trim().length > 0) {
- fmt += " " + k;
- if (t.attributes[k].trim().length > 0) {
- var delim = '"';
- if (t.attributes[k].match(/[^\\]"/)) {
- delim = "'";
- if (t.attributes[k].match(/[^\\]'/)) {
- delim = "`";
- }
- }
- fmt += "=" + delim + t.attributes[k] + delim;
- }
- }
- }
- str = str.replace(t.text, fmt + ">");
- i = str.indexOf("<", i + fmt.length + 1);
- }
-
- return str;
+var ATTRIBUTE_MAP = {
+ a: ["href", "name", "target"],
+ font: ["size"],
+ img: ["src"],
+ marquee: ["behavior", "behaviour", "direction", "scrollamount"],
+ table: ["cellpadding", "cellspacing"],
+ th: ["colspan", "rowspan"],
+ td: ["colspan", "rowspan"]
}
-/* WIP: Sanitize a string where HTML is prohibited */
+for (var key in ATTRIBUTE_MAP) {
+ ALLOWED_ATTRIBUTES.forEach(function (attr) {
+ ATTRIBUTE_MAP[key].push(attr);
+ });
+}
+
+sanitizeHTML.defaults.allowedTags.concat(ALLOWED_TAGS).forEach(function (tag) {
+ if (!(tag in ATTRIBUTE_MAP)) {
+ ATTRIBUTE_MAP[tag] = ALLOWED_ATTRIBUTES;
+ }
+});
+
+const SETTINGS = {
+ allowedTags: sanitizeHTML.defaults.allowedTags.concat(ALLOWED_TAGS),
+ allowedAttributes: ATTRIBUTE_MAP
+};
+
function sanitizeText(str) {
str = str.replace(/&/g, "&")
.replace(/