Firefox Extension that enables Slack Huddles on Linux

Slack blocks the use of huddles on Firefox for Linux. This extension
enables the use of huddles by spoofing a Windows user-agent.

This extension currently only works on Linux x86_64.

.gitignore

@@ -0,0 +1 @@
+*.xpi

Makefile

@@ -0,0 +1,13 @@
+release: clean prod
+ zip -r -FS slack.xpi *.json *.js
+
+debug:
+ sed -i 's;\.slack\.com;.browserleaks.com;g' *.json *.js
+
+prod production:
+ sed -i 's;\.browserleaks\.com;.slack.com;g' *.json *.js
+
+clean:
+ rm -f slack.xpi
+
+.PHONY: release debug prod production clean

http.js

@@ -0,0 +1,23 @@
+"use strict";
+
+/**
+ * Rewrite the User-Agent header to be Windows.
+ */
+function rewriteUserAgentHeader(e) {
+ for (let header of e.requestHeaders) {
+ if (header.name.toLowerCase() === "user-agent") {
+ header.value = header.value.replace("X11; Linux x86_64;", "Windows NT 10.0; Win64; x64;");
+ }
+ }
+ return {requestHeaders: e.requestHeaders};
+}
+
+/**
+ * Add rewriteUserAgentHeader as a listener to onBeforeSendHeaders,
+ * only for the target page.
+ *
+ * Make it "blocking" so we can modify the headers.
+ */
+browser.webRequest.onBeforeSendHeaders.addListener(rewriteUserAgentHeader,
+ {urls: ["*://*.slack.com/*"]},
+ ["blocking", "requestHeaders"]);

inject.js

@@ -0,0 +1,17 @@
+function main() {
+ if (navigator.platform === "Linux x86_64") {
+ Object.defineProperties(navigator, {
+ 'appVersion': {
+ value: "5.0 (Windows)"
+ },
+ 'oscpu': {
+ value: "Windows NT 10.0; Win64; x64"
+ },
+ 'platform': {
+ value: "Win32"
+ }
+ });
+ }
+}
+
+main();

manifest.json

@@ -0,0 +1,34 @@
+{
+ "manifest_version": 2,
+ "name": "Slack Huddles for Linux",
+ "version": "0.4",
+ "description": "Enables Slack Huddles on Linux via User-Agent spoofing.",
+
+ "browser_specific_settings": {
+ "gecko": {
+ "id": "slack@chaotic-neutral.org"
+ }
+ },
+
+ "permissions": [
+ "webRequest",
+ "webRequestBlocking",
+ "*://*.slack.com/*"
+ ],
+
+ "web_accessible_resources": [
+ "inject.js"
+ ],
+
+ "background": {
+ "scripts": ["http.js"]
+ },
+
+ "content_scripts": [
+ {
+ "matches": ["*://*.slack.com/*"],
+ "js": ["navigator.js"],
+ "run_at": "document_start"
+ }
+ ]
+}

navigator.js

@@ -0,0 +1,7 @@
+function main() {
+ const script = document.createElement('script');
+ script.src = chrome.runtime.getURL('inject.js');
+ document.documentElement.appendChild(script);
+}
+
+main();